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Creativity break: Why is algebra important to learn? | https://www.youtube.com/watch?v=H4g0GZsgq0I | vtt | https://www.youtube.com/api/timedtext?v=H4g0GZsgq0I&ei=uVWUZYyEHYrGp-oP7aSY-A8&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245289&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=2E47D2247AA61974C9A6EA75208C570460C1AFF9.099604D75281109056C267F734228DF5F7EDEADE&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:01.002 --> 00:00:04.002
(marker scratching)
00:00:05.292 --> 00:00:08.459
(gentle upbeat music)
00:00:09.870 --> 00:00:13.490
- Algebra is really the unifying thread
00:00:13.490 --> 00:00:16.100
of almost all of mathematics.
00:00:16.100 --> 00:00:18.250
You may think algebra is boring,
00:00:18.250 --> 00:00:22.490
but it is the one tool you can
use to not only understand,
00:00:22.490 --> 00:00:24.580
but unlock the universe.
00:00:24.580 --> 00:00:27.830
Creative algebra is used
in computer game design.
00:00:27.830 --> 00:00:31.810
It powers how artificial
intelligence works.
00:00:31.810 --> 00:00:34.880
Mastering algebra will
provide you with the ability
00:00:34.880 --> 00:00:38.287
to decode and understand
many complex systems.
00:00:38.287 --> 00:00:41.130
In my opinion, if you can master algebra,
00:00:41.130 --> 00:00:42.330
you can master anything.
|
Creativity break: What do you do to get into your creative zone? | https://www.youtube.com/watch?v=7WjlO5u3Vqo | vtt | https://www.youtube.com/api/timedtext?v=7WjlO5u3Vqo&ei=uVWUZcy4GfWQvdIPvaOrsAE&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245289&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=E1A7181765BACBB97A21231A1C1D365D1B3BB2E2.C1FB1F6C51050ABCE239D8BB6C07DE326AA6525F&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.323 --> 00:00:02.740
(soft music)
00:00:03.717 --> 00:00:06.210
(marker scratches)
00:00:06.210 --> 00:00:08.877
(keyboard taps)
00:00:10.300 --> 00:00:14.050
- Whenever I wanna come up
with a solution to a problem
00:00:14.050 --> 00:00:15.330
and I don't have it,
00:00:15.330 --> 00:00:20.100
my immediate reaction is to
go outside and go on a walk.
00:00:20.100 --> 00:00:22.173
I love walking in all kinds of weather.
00:00:25.348 --> 00:00:27.203
I feel like with the peace and calm,
00:00:27.203 --> 00:00:31.100
moving away from the problem
and stepping away from it,
00:00:31.100 --> 00:00:35.200
sometimes I get way better
ideas and it inspires me.
00:00:35.200 --> 00:00:36.570
But, I also think there's
something to be said
00:00:36.570 --> 00:00:38.930
about not being inspired.
00:00:38.930 --> 00:00:41.110
Like, not always as amazing.
00:00:41.110 --> 00:00:44.770
I feel like sometimes I
get struck with inspiration
00:00:44.770 --> 00:00:47.900
for how I want to explain
a Khan Academy video
00:00:47.900 --> 00:00:49.720
or how I wanna approach a piece of art
00:00:49.720 --> 00:00:52.830
or how I want to approach a math problem,
00:00:52.830 --> 00:00:54.540
but sometimes it doesn't come.
00:00:54.540 --> 00:00:56.830
And so I feel like what
the best solution is
00:00:56.830 --> 00:00:58.770
when you are trying to get
into that creative zone
00:00:58.770 --> 00:01:00.660
and you can't, is just do it
00:01:00.660 --> 00:01:03.470
and try to do something anyway.
00:01:03.470 --> 00:01:06.960
Like write something or
write your equations,
00:01:06.960 --> 00:01:08.380
try to figure it out.
00:01:08.380 --> 00:01:10.530
And if you make mistakes, that's okay,
00:01:10.530 --> 00:01:11.830
because it's something to jump off of
00:01:11.830 --> 00:01:16.020
and sometimes seeing what you
already know down on paper
00:01:16.020 --> 00:01:18.040
can help you come up with better ideas
00:01:18.040 --> 00:01:19.700
and can help you be more creative.
00:01:19.700 --> 00:01:22.010
- Forcing yourself to
just conjure a solution,
00:01:22.010 --> 00:01:23.360
simply does not work.
00:01:23.360 --> 00:01:25.130
Instead, take a break from the task.
00:01:25.130 --> 00:01:26.070
Pick something else up,
00:01:26.070 --> 00:01:29.000
like a physical sport or even video games.
00:01:29.000 --> 00:01:31.060
And then come back to
the original problem.
00:01:31.060 --> 00:01:32.838
That can do wonders.
00:01:32.838 --> 00:01:35.255
(soft music)
|
Creativity break: How does creativity play a role in your everyday life? | https://www.youtube.com/watch?v=eU8IfaoD-v8 | vtt | https://www.youtube.com/api/timedtext?v=eU8IfaoD-v8&ei=uVWUZcPDG7y7vdIPpquLuAg&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245289&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=64D52CA6B3320729DE507928DC3BD7E262E4FC3B.1A4D821456777BFB3377BAE22FAE57195769E9B9&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.000 --> 00:00:02.583
(upbeat music)
00:00:10.310 --> 00:00:11.830
- Creativity is really important for me
00:00:11.830 --> 00:00:14.610
as like a future job, as
a part of my future job
00:00:14.610 --> 00:00:18.370
I would want to do something that changes
00:00:18.370 --> 00:00:21.430
and then I can use problem
solving skills constantly.
00:00:21.430 --> 00:00:24.560
I feel like when I make
animations or when I figure
00:00:24.560 --> 00:00:26.010
out how to explain something,
00:00:28.080 --> 00:00:31.160
I love that because there's
so many different solutions,
00:00:31.160 --> 00:00:33.770
but knowing that you can
try to find and experiment
00:00:33.770 --> 00:00:36.630
with different ones and maybe
create something beautiful
00:00:36.630 --> 00:00:39.990
is really, I don't know, inspiring to me.
00:00:39.990 --> 00:00:42.750
- Mathematicals educational initiative
00:00:42.750 --> 00:00:45.360
that I co-founded with
a fellow mathematician,
00:00:45.360 --> 00:00:46.710
Jess Williams.
00:00:46.710 --> 00:00:50.400
And what we're trying to do is
make maths fun and accessible
00:00:50.400 --> 00:00:54.240
and encourage more girls
to pursue careers in maths.
00:00:54.240 --> 00:00:56.570
So creativity is essential here
00:00:56.570 --> 00:00:57.770
because we're trying to think
00:00:57.770 --> 00:01:01.540
of ways that people will enjoy maths
00:01:01.540 --> 00:01:03.960
and it will be fun and accessible to them.
00:01:03.960 --> 00:01:05.950
So different creative
techniques that we've been
00:01:05.950 --> 00:01:09.750
using are trying to present
mathematical problems
00:01:09.750 --> 00:01:14.500
in fun, short videos, and
that explain the problem
00:01:14.500 --> 00:01:16.850
in a way that everybody will understand
00:01:16.850 --> 00:01:18.900
and will make them want to learn more
00:01:18.900 --> 00:01:21.900
and discover more about the
topics that we're talking about.
00:01:21.900 --> 00:01:23.500
- I'm really lucky
00:01:23.500 --> 00:01:27.470
that I get to be creative
every day in my work
00:01:27.470 --> 00:01:30.840
and I have been since I got
into this field of data science.
00:01:30.840 --> 00:01:33.680
So in general, across the last decade,
00:01:33.680 --> 00:01:36.670
my work has really been about designing
00:01:36.670 --> 00:01:40.840
and testing innovative ways
to capture human behavior
00:01:40.840 --> 00:01:43.230
within game-based assessments.
00:01:43.230 --> 00:01:44.900
So my collaborators and I,
00:01:44.900 --> 00:01:47.930
from the time I was in
graduate school to now,
00:01:47.930 --> 00:01:50.220
use a variety of different
modeling techniques
00:01:50.220 --> 00:01:51.200
from various fields,
00:01:51.200 --> 00:01:55.550
we'll pull things from
engineering, aerospace,
00:01:55.550 --> 00:01:59.480
more basic mathematical models
to help us achieve this goal.
00:01:59.480 --> 00:02:01.100
We get to think outside the box.
00:02:01.100 --> 00:02:04.130
We get to think about how we
can pull in different types
00:02:04.130 --> 00:02:06.980
of thinking from different
fields to help us better
00:02:06.980 --> 00:02:11.980
understand human behavior,
human cognition, learning.
00:02:12.020 --> 00:02:14.600
So it's really exciting and really novel.
00:02:14.600 --> 00:02:17.370
And it's something that because
of the field that I'm in
00:02:17.370 --> 00:02:20.433
I've been able to do this
now for multiple years.
|
Creativity break: How can people get creative in algebra | https://www.youtube.com/watch?v=DXPz0-HCK80 | vtt | https://www.youtube.com/api/timedtext?v=DXPz0-HCK80&ei=uVWUZaLkCtedmLAPxoyyiAI&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245289&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=ACD53E23DFB695E001D8659457D6624EA2DC4161.703508D563A5741487B06AFB9CF0B52BCF7EE5EF&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.000 --> 00:00:02.583
(upbeat music)
00:00:10.280 --> 00:00:12.130
- In order to get more creative,
00:00:12.130 --> 00:00:13.730
I would encourage young people
00:00:13.730 --> 00:00:16.730
to be not afraid of making mistakes.
00:00:16.730 --> 00:00:21.510
It's okay to fail while
exploring a new trail of thought.
00:00:21.510 --> 00:00:23.980
Know that usually there
is more than one solution
00:00:23.980 --> 00:00:25.370
to the problem.
00:00:25.370 --> 00:00:30.370
Math is as much about posing
problems as problem solving.
00:00:30.890 --> 00:00:33.810
And at that point, creativity is noticing
00:00:33.810 --> 00:00:36.060
where there is something
worthwhile investigating.
00:00:36.060 --> 00:00:37.440
- As a student in math,
00:00:37.440 --> 00:00:39.100
I think it's important to remember
00:00:39.100 --> 00:00:44.100
that math isn't just like
random symbols on paper.
00:00:44.100 --> 00:00:46.260
Like math can mean something
00:00:46.260 --> 00:00:49.770
and it's pretty powerful
that you as a student
00:00:49.770 --> 00:00:51.730
can build something that uses math.
00:00:51.730 --> 00:00:53.840
Creativity in math isn't just about
00:00:53.840 --> 00:00:55.430
being able to pluck numbers from the air
00:00:55.430 --> 00:00:57.410
and like, oh yes, I know the solution.
00:00:57.410 --> 00:01:01.310
It's about being able to use problems
00:01:01.310 --> 00:01:02.993
that help with your daily life.
|
Creativity break: When did you first realize that you liked algebra | https://www.youtube.com/watch?v=4l1t-_Eb2MI | vtt | https://www.youtube.com/api/timedtext?v=4l1t-_Eb2MI&ei=uVWUZaPIB_u4vdIPus-juAI&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245289&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=280353DE6E5D80EF264A046ACB51F041D573170C.538D9C7766E85431CF6C892222E8E301609B8D22&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.366 --> 00:00:04.116
(whimsical electronic music)
00:00:06.294 --> 00:00:08.544
(clicking)
00:00:11.230 --> 00:00:14.020
- One day, my family
was building this fence
00:00:14.020 --> 00:00:17.260
around my chicken coop.
00:00:17.260 --> 00:00:19.400
'Cause there were problems with raccoons.
00:00:19.400 --> 00:00:22.400
And we wanted to make sure
that the perimeter of the fence
00:00:22.400 --> 00:00:26.950
was twice the the length of the width.
00:00:26.950 --> 00:00:27.787
And I remember thinking,
00:00:27.787 --> 00:00:30.457
"This is exactly like my algebra class.
00:00:30.457 --> 00:00:35.457
"I'm actually doing
things that are useful."
00:00:35.490 --> 00:00:39.040
Algebra wasn't just something
that you do on paper,
00:00:39.040 --> 00:00:42.110
it was actually protecting
the lives of my chickens.
00:00:42.110 --> 00:00:44.150
So I felt like that was a moment for me
00:00:44.150 --> 00:00:47.070
where math is useful to the world,
00:00:47.070 --> 00:00:49.580
and we're solving real problems with it,
00:00:49.580 --> 00:00:51.370
and it's really powerful.
00:00:51.370 --> 00:00:54.230
- So I realized that
I first liked algebra,
00:00:54.230 --> 00:00:57.090
and just math in general,
my first year in college,
00:00:57.090 --> 00:00:58.770
I was a little bit of a late bloomer
00:00:58.770 --> 00:01:00.730
in realizing the importance of math.
00:01:00.730 --> 00:01:02.940
I was taking an early statistics course
00:01:02.940 --> 00:01:04.700
for my psychology degree.
00:01:04.700 --> 00:01:06.690
And I really began to understand
00:01:06.690 --> 00:01:08.910
how the concepts that I were learning
00:01:10.370 --> 00:01:12.900
could help me understand
the world around me better
00:01:12.900 --> 00:01:16.630
in a more concrete, fluid, and rich way.
00:01:16.630 --> 00:01:18.450
And so being able to make that connection
00:01:18.450 --> 00:01:20.710
from these things that I'm
learning in the classroom
00:01:20.710 --> 00:01:21.660
out into the real world,
00:01:21.660 --> 00:01:23.470
so that I can under understand
different phenomenon,
00:01:23.470 --> 00:01:26.650
I can understand how various
things in our culture
00:01:26.650 --> 00:01:29.980
work and progress, really helped me
00:01:29.980 --> 00:01:32.220
and made me feel like I
had a deeper understanding
00:01:32.220 --> 00:01:35.560
for the importance of math and algebra.
00:01:35.560 --> 00:01:37.810
And from that point I've
really been in love.
|
Creativity break: How do you apply creativity in algebra | https://www.youtube.com/watch?v=2vAMs-KM7UA | vtt | https://www.youtube.com/api/timedtext?v=2vAMs-KM7UA&ei=uVWUZYncDJKvp-oP_66TEA&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245289&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=26E902F0BB2A7B1A3CFC8E6256AAF4C436312D47.6E6F8CD8FA2D692E13E2D582EDD4D297E594822A&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.176 --> 00:00:02.759
(gentle music)
00:00:10.610 --> 00:00:13.240
- So if you're trying to
communicate a complex topic,
00:00:13.240 --> 00:00:15.980
such as mathematics or
a mathematical problem
00:00:15.980 --> 00:00:17.410
to the general public,
00:00:17.410 --> 00:00:20.070
who might not be familiar
with the specifics
00:00:20.070 --> 00:00:21.194
behind that problem,
00:00:21.194 --> 00:00:22.950
there are many different ways
00:00:22.950 --> 00:00:25.418
to help you get that concept across.
00:00:25.418 --> 00:00:27.250
And one of the ways that we do this
00:00:27.250 --> 00:00:29.870
in mathematical is to use videos
00:00:29.870 --> 00:00:32.700
and things that are visually
appealing to people.
00:00:32.700 --> 00:00:34.980
So by using lots of visual aids,
00:00:34.980 --> 00:00:37.670
so bright colors and cartoons,
00:00:37.670 --> 00:00:40.610
and word prompts on your screen,
00:00:40.610 --> 00:00:44.620
you can engage and capture
the audience in different ways
00:00:44.620 --> 00:00:45.773
that you might not be able to do
00:00:45.773 --> 00:00:47.700
if you're just speaking
00:00:47.700 --> 00:00:49.830
in terms of equations and mathematics.
00:00:49.830 --> 00:00:51.160
- When we're more creative
00:00:51.160 --> 00:00:53.600
about how we present and
how we talk about math
00:00:53.600 --> 00:00:54.810
it makes it more relatable
00:00:54.810 --> 00:00:57.280
to people from a variety of backgrounds
00:00:57.280 --> 00:00:59.243
and cultures and experiences.
00:01:00.240 --> 00:01:01.710
When we are creative
00:01:01.710 --> 00:01:06.110
in how we explain or how we
relate mathematical concepts,
00:01:06.110 --> 00:01:08.490
we can use things from
sports, entertainment,
00:01:08.490 --> 00:01:11.140
or real world to help
really ground the principles
00:01:11.140 --> 00:01:12.320
that we're learning
00:01:12.320 --> 00:01:14.940
and the theories that we're
learning to something relatable.
00:01:14.940 --> 00:01:17.760
So the more creative we can
be in explaining how math
00:01:17.760 --> 00:01:19.330
is related to the world around us,
00:01:19.330 --> 00:01:22.180
how it's related to things
that we are invested in,
00:01:22.180 --> 00:01:25.010
the more likely it is to resonate
with the people around us.
00:01:25.010 --> 00:01:27.110
- As soon as a problem is posed
00:01:27.110 --> 00:01:30.660
our instinct is to find the solution.
00:01:30.660 --> 00:01:33.340
But remember, often there's
more than one solution
00:01:33.340 --> 00:01:35.401
and usually there's more
than one path to it.
00:01:35.401 --> 00:01:37.984
(gentle music)
|
Creativity break: Why is creativity important in STEM jobs? | https://www.youtube.com/watch?v=ynvn3jqxcX4 | vtt | https://www.youtube.com/api/timedtext?v=ynvn3jqxcX4&ei=uVWUZeXLDOKkvdIPp8CAmAU&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245289&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=16E0182E4FE9F9FFA86F3D926BB3617244CB3C6C.761C3F5FFB461A136A44C6E173903237BFA4733B&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.323 --> 00:00:03.323
(soft upbeat music)
00:00:10.480 --> 00:00:14.760
- I think my idea of how
creativity works in STEM jobs
00:00:14.760 --> 00:00:18.270
has changed since I've gone to college.
00:00:18.270 --> 00:00:20.240
I used to think that
all the mathematicians
00:00:20.240 --> 00:00:22.890
would be locked away in some office
00:00:22.890 --> 00:00:24.130
and typing on the computers
00:00:24.130 --> 00:00:26.410
or writing down equations by themselves
00:00:26.410 --> 00:00:28.890
and coming up with
incredibly beautiful ideas
00:00:28.890 --> 00:00:30.160
just by themselves.
00:00:30.160 --> 00:00:32.100
But I'm realizing now that I'm in college
00:00:32.100 --> 00:00:35.210
that mathematics and creativity,
00:00:35.210 --> 00:00:36.880
it's a lot about communication,
00:00:36.880 --> 00:00:37.713
and it's a lot about
00:00:37.713 --> 00:00:40.540
trying to build off of each other's ideas
00:00:40.540 --> 00:00:42.852
and bounce ideas off of each other
00:00:42.852 --> 00:00:47.200
and build upon ideas that
have already been made
00:00:47.200 --> 00:00:48.940
by people decades ago.
00:00:48.940 --> 00:00:52.490
And I think that the facts
that we all come with it,
00:00:52.490 --> 00:00:53.590
with our own perspectives,
00:00:53.590 --> 00:00:58.359
and different ideas and
different ways of being creative
00:00:58.359 --> 00:01:01.020
allows math to advance further,
00:01:01.020 --> 00:01:03.760
because we can all
combine our creative ideas
00:01:03.760 --> 00:01:04.960
into something bigger.
00:01:04.960 --> 00:01:07.700
- We collect data on everything, right?
00:01:07.700 --> 00:01:09.860
And so the ability to use that data
00:01:09.860 --> 00:01:13.510
in a smart, safe, and efficient way
00:01:13.510 --> 00:01:17.170
depends on new applications
of mathematical concepts
00:01:17.170 --> 00:01:19.833
to these new and innovative data sets.
00:01:20.850 --> 00:01:22.150
As we get to that point,
00:01:22.150 --> 00:01:24.438
we'll start to be thinking
outside the box a lot more,
00:01:24.438 --> 00:01:28.560
and we'll be a much more
innovative, digital society,
00:01:28.560 --> 00:01:31.260
but that can't happen unless
we start trying to be creative,
00:01:31.260 --> 00:01:33.839
and not just rely on tried and true.
00:01:33.839 --> 00:01:36.823
(soft upbeat music)
|
Creativity break: Why is creativity important in algebra? | https://www.youtube.com/watch?v=SjZfW07DbMo | vtt | https://www.youtube.com/api/timedtext?v=SjZfW07DbMo&ei=uVWUZcjdF6DoxN8P8vyxyAQ&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245289&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=E36EC59A24AC8DB3731375B7281605D47C502E08.0CFE3E5EE772F64826E0848A451433F17897F7E8&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.198 --> 00:00:02.781
(upbeat music)
00:00:11.080 --> 00:00:13.620
- It's all about solving problems.
00:00:13.620 --> 00:00:16.210
It's not about, like
maybe in previous years
00:00:16.210 --> 00:00:19.760
you've done multiplication
table memorization.
00:00:19.760 --> 00:00:22.350
It's not like memorizing
how to solve problems.
00:00:22.350 --> 00:00:24.880
It's learning the tools
of how to solve problems
00:00:24.880 --> 00:00:28.760
and then using them and building
them up in creative ways.
00:00:28.760 --> 00:00:31.330
So it really does remind me of art
00:00:31.330 --> 00:00:34.340
because if you are doing
a painting or something,
00:00:34.340 --> 00:00:37.280
you have specific tools
about maybe paint brushes
00:00:37.280 --> 00:00:39.700
or different techniques you can use
00:00:39.700 --> 00:00:41.600
to create something bigger.
00:00:41.600 --> 00:00:46.100
So I feel like algebra is really
all about combining things
00:00:46.100 --> 00:00:48.980
that you already know how
to do into something bigger.
00:00:48.980 --> 00:00:53.980
- So the word algebra comes
from the Arabic word algebra
00:00:54.120 --> 00:00:59.120
that literally translates
to reunion of broken parts.
00:00:59.720 --> 00:01:03.470
This is breaking apart of
mathematical representations
00:01:03.470 --> 00:01:05.200
and putting it back together
00:01:05.200 --> 00:01:07.630
in the form of balanced equations
00:01:07.630 --> 00:01:09.530
is the essence of algebra.
00:01:09.530 --> 00:01:12.650
And the beautiful thing
is that this balancing
00:01:12.650 --> 00:01:16.360
and solving of equations can
be done in many different ways
00:01:16.360 --> 00:01:18.423
which is where creativity comes in.
|
Creativity in algebra | https://www.youtube.com/watch?v=nOBZM5QYcBc | vtt | https://www.youtube.com/api/timedtext?v=nOBZM5QYcBc&ei=uVWUZebsGbuJp-oPrp6j8AY&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245289&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=0B81554C15D967B5D8AF6F96765D41977EE23A7E.F11295401CED4B0E013C431ADC2D39CCCE621101&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.976 --> 00:00:03.559
(upbeat music)
00:00:11.120 --> 00:00:13.270
- Hi folks, Sal Khan here.
00:00:13.270 --> 00:00:16.014
And all I have to say is
that algebra is perhaps
00:00:16.014 --> 00:00:20.840
the most pure way of
expressing human thought.
00:00:20.840 --> 00:00:22.650
And like everything
dealing with human thought,
00:00:22.650 --> 00:00:24.443
it's incredibly creative.
00:00:25.790 --> 00:00:28.160
But you don't have to take my word for it.
00:00:28.160 --> 00:00:31.800
We have some of my good friends
to better draw that link
00:00:31.800 --> 00:00:34.871
between algebra and creativity.
00:00:34.871 --> 00:00:37.454
(upbeat music)
00:00:39.930 --> 00:00:42.460
- It's all out solving problems.
00:00:42.460 --> 00:00:45.050
It's not about like,
maybe in previous years,
00:00:45.050 --> 00:00:48.580
you've done multiplication
table memorization.
00:00:48.580 --> 00:00:51.170
It's not like memorizing
how to solve problems.
00:00:51.170 --> 00:00:53.720
It's learning the tools
of how to solve problems
00:00:53.720 --> 00:00:57.600
and then using them, and building
them up in creative ways.
00:00:57.600 --> 00:01:00.170
So it's kind of like, it
really does remind me of art,
00:01:00.170 --> 00:01:03.160
because if you are doing
like a painting or something,
00:01:03.160 --> 00:01:06.120
you have like a specific tools
about maybe paint brushes
00:01:06.120 --> 00:01:07.985
or different techniques you can use
00:01:07.985 --> 00:01:10.440
to create something bigger.
00:01:10.440 --> 00:01:14.940
So I feel like algebra is really
all about combining things
00:01:14.940 --> 00:01:17.800
that you already know how
to do into something bigger.
00:01:17.800 --> 00:01:22.800
- So the word algebra comes
from the Arabic word al-jabr,
00:01:22.930 --> 00:01:27.930
that literally translates
to reunion of broken parts.
00:01:28.560 --> 00:01:32.320
This breaking apart of
mathematic representations
00:01:32.320 --> 00:01:34.030
and putting it back together
00:01:34.030 --> 00:01:36.470
in the form of balanced equations,
00:01:36.470 --> 00:01:38.390
is the essence of algebra.
00:01:38.390 --> 00:01:39.790
And the beautiful thing is that
00:01:39.790 --> 00:01:42.890
this balancing and solving of equations
00:01:42.890 --> 00:01:45.210
can be done in many different ways,
00:01:45.210 --> 00:01:47.805
which is where creativity comes in.
00:01:47.805 --> 00:01:50.388
(upbeat music)
00:01:52.320 --> 00:01:54.970
- So if you're trying to
communicate a complex topic,
00:01:54.970 --> 00:01:57.700
such as mathematics or
a mathematical problem
00:01:57.700 --> 00:02:00.740
to the general public
who might not be familiar
00:02:00.740 --> 00:02:03.340
with the specifics behind that problem,
00:02:03.340 --> 00:02:04.670
there are many different ways
00:02:04.670 --> 00:02:07.530
to help you get that concept across.
00:02:07.530 --> 00:02:10.070
And one of the ways that
we do this in mathematicals
00:02:10.070 --> 00:02:12.120
is to use videos and things
00:02:12.120 --> 00:02:14.420
that are visually appealing to people.
00:02:14.420 --> 00:02:16.700
So by using lots of visual aids,
00:02:16.700 --> 00:02:19.400
so bright colors and cartoons,
00:02:19.400 --> 00:02:22.330
and word prompts on your screen,
00:02:22.330 --> 00:02:25.520
you can engage and capture the audience
00:02:25.520 --> 00:02:27.950
in different ways that you
might not be able to do
00:02:27.950 --> 00:02:29.920
if you're just speaking in terms
00:02:29.920 --> 00:02:31.540
of equations and mathematics.
00:02:31.540 --> 00:02:34.030
- When we're more creative
about how we present,
00:02:34.030 --> 00:02:35.300
and how we talk about math,
00:02:35.300 --> 00:02:37.040
it makes it more relatable to people
00:02:37.040 --> 00:02:41.220
from a variety of backgrounds
and cultures and experiences.
00:02:41.220 --> 00:02:44.820
When we are creative in how we explain,
00:02:44.820 --> 00:02:47.840
or how we relate mathematical concepts,
00:02:47.840 --> 00:02:51.150
we can use things from sports,
entertainment, or real world
00:02:51.150 --> 00:02:53.827
to help really ground the
principles that we're learning,
00:02:53.827 --> 00:02:56.660
and the theories that we're
learning to something relatable.
00:02:56.660 --> 00:02:59.480
So the more creative we can
be in explaining how math
00:02:59.480 --> 00:03:01.050
is related to the world around us,
00:03:01.050 --> 00:03:03.910
how it's related to things
that we are invested in,
00:03:03.910 --> 00:03:06.820
the more likely it is to resonate
with the people around us.
00:03:06.820 --> 00:03:08.850
- As soon as a problem is posed,
00:03:08.850 --> 00:03:12.380
our instinct is to find the solution.
00:03:12.380 --> 00:03:15.050
But remember, often there's
more than one solution.
00:03:15.050 --> 00:03:17.972
And usually there's more
than one path to it.
00:03:17.972 --> 00:03:20.889
(keyboard tapping)
00:03:23.060 --> 00:03:25.860
- One day my family
was building this fence
00:03:25.860 --> 00:03:29.070
around my chicken coop
00:03:29.070 --> 00:03:31.530
'cause there were problems with raccoons.
00:03:31.530 --> 00:03:32.660
And we wanted to make sure that,
00:03:32.660 --> 00:03:34.847
like the the perimeter
of the fence was like,
00:03:34.847 --> 00:03:38.920
twice the the length of the width.
00:03:38.920 --> 00:03:39.753
And I remember thinking,
00:03:39.753 --> 00:03:41.940
this is exactly like my algebra class.
00:03:41.940 --> 00:03:46.270
Like, I'm actually doing
things that are useful.
00:03:46.270 --> 00:03:49.180
And actually, like algebra
wasn't just something
00:03:49.180 --> 00:03:50.013
that you do on paper,
00:03:50.013 --> 00:03:52.370
it's something that like, it
was actually like protecting
00:03:52.370 --> 00:03:53.920
the lives of my chickens.
00:03:53.920 --> 00:03:55.990
So I felt like that was a moment for me
00:03:55.990 --> 00:03:58.920
where like math is useful to the worlds,
00:03:58.920 --> 00:04:01.410
and we're solving real problems with it,
00:04:01.410 --> 00:04:03.180
and it's really powerful.
00:04:03.180 --> 00:04:06.050
- So I realized that I first liked algebra
00:04:06.050 --> 00:04:07.790
and just math in general.
00:04:07.790 --> 00:04:08.930
My first year in college,
00:04:08.930 --> 00:04:10.610
I was a little bit of a late bloomer
00:04:10.610 --> 00:04:12.570
in realizing the importance of math.
00:04:12.570 --> 00:04:14.770
I was taking an early statistics course
00:04:14.770 --> 00:04:16.550
for my psychology degree,
00:04:16.550 --> 00:04:19.660
and I really began to
understand how the concepts
00:04:19.660 --> 00:04:23.400
that I were learning
could help me understand
00:04:23.400 --> 00:04:26.532
the world around me
better in a more concrete,
00:04:26.532 --> 00:04:28.470
fluid and rich way.
00:04:28.470 --> 00:04:30.280
And so being able to make that connection
00:04:30.280 --> 00:04:32.550
from these things that I'm
learning in the classroom,
00:04:32.550 --> 00:04:33.490
out into the real world,
00:04:33.490 --> 00:04:35.300
so I can understand different phenomenon,
00:04:35.300 --> 00:04:37.770
I can understand how various things
00:04:37.770 --> 00:04:40.347
in our culture work and progress,
00:04:40.347 --> 00:04:42.550
really helped me and made me feel
00:04:42.550 --> 00:04:43.704
like I had a deeper understanding
00:04:43.704 --> 00:04:47.390
for the importance of math and algebra.
00:04:47.390 --> 00:04:49.724
And from that point,
I've really been in love.
00:04:49.724 --> 00:04:52.307
(upbeat music)
00:04:54.870 --> 00:04:56.720
- In order to get more creative,
00:04:56.720 --> 00:04:59.840
I would encourage young
people to be not afraid
00:04:59.840 --> 00:05:01.320
of making mistakes.
00:05:01.320 --> 00:05:06.130
It's okay to fail while
exploring a new trail of thought.
00:05:06.130 --> 00:05:08.580
Know that usually there
is more than one solution
00:05:08.580 --> 00:05:09.970
to the problem.
00:05:09.970 --> 00:05:14.970
Math is as much about posing
problems as problem solving.
00:05:15.470 --> 00:05:18.410
And at that point, creativity is noticing
00:05:18.410 --> 00:05:20.830
where there is something
worthwhile investigating.
00:05:20.830 --> 00:05:23.700
- As a student in math, I think
it's important to remember
00:05:23.700 --> 00:05:28.690
that math isn't just like
random symbols on paper.
00:05:28.690 --> 00:05:33.110
Like, math can mean something,
and it's pretty powerful
00:05:33.110 --> 00:05:36.320
that you as a student, can
build something that uses math.
00:05:36.320 --> 00:05:38.820
Creativity in math isn't
just about being able
00:05:38.820 --> 00:05:40.340
to pluck numbers from the air and like,
00:05:40.340 --> 00:05:42.020
oh yes, I know the solution.
00:05:42.020 --> 00:05:45.930
It's about being able to use problems
00:05:45.930 --> 00:05:47.603
that help with your daily life.
|
Creative algebra at work | https://www.youtube.com/watch?v=Ep7diUpHuhs | vtt | https://www.youtube.com/api/timedtext?v=Ep7diUpHuhs&ei=uVWUZfySHJ2nvdIPvr2v-Aw&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245289&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=6B9358FE28E17555D027A7442897CF12AFE369.A71AFC7A07447AC574301EF22A48459F2994060C&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.254 --> 00:00:02.754
(light music)
00:00:11.780 --> 00:00:13.760
- Hi, everyone, Sal Khan here.
00:00:13.760 --> 00:00:16.700
I've always been drawn to creative things.
00:00:16.700 --> 00:00:19.380
I like to see, change
new things in the world,
00:00:19.380 --> 00:00:20.450
and because of that,
00:00:20.450 --> 00:00:22.340
I've been drawn to careers
00:00:22.340 --> 00:00:25.130
where I can most apply my creativity,
00:00:25.130 --> 00:00:27.900
especially in an abstract sense.
00:00:27.900 --> 00:00:31.760
And algebra is perhaps the
purest expression of creativity,
00:00:31.760 --> 00:00:33.700
and that's why I've worked in everything
00:00:33.700 --> 00:00:37.730
from computer programming,
to product design,
00:00:37.730 --> 00:00:40.490
to a hedge fund analyst,
00:00:40.490 --> 00:00:42.130
where you're investing in stocks.
00:00:42.130 --> 00:00:43.040
And in all of them,
00:00:43.040 --> 00:00:47.670
it was incredibly creative
and used a lot of algebra.
00:00:47.670 --> 00:00:49.290
But don't take my word for it.
00:00:49.290 --> 00:00:50.880
You're going to meet some of my friends
00:00:50.880 --> 00:00:53.280
who can tell you a lot
more about the connection
00:00:53.280 --> 00:00:57.202
between algebra and work and creativity.
00:00:57.202 --> 00:00:58.626
(typewriter typing)
00:00:58.626 --> 00:01:01.800
(light music continues)
00:01:01.800 --> 00:01:04.830
- I think my idea of how creativity works
00:01:04.830 --> 00:01:09.420
in STEM jobs has changed
since I've gotten to college.
00:01:09.420 --> 00:01:11.560
I used to think that
all the mathematicians
00:01:11.560 --> 00:01:14.170
would be just locked away in some office
00:01:14.170 --> 00:01:17.060
and typing on their computers
or writing down equations
00:01:17.060 --> 00:01:20.210
by themselves and coming up
with incredibly beautiful ideas
00:01:20.210 --> 00:01:21.480
just by themselves.
00:01:21.480 --> 00:01:23.420
But I'm realizing now that I'm in college
00:01:23.420 --> 00:01:26.530
that mathematics and creativity,
00:01:26.530 --> 00:01:28.190
it's a lot about communication
00:01:28.190 --> 00:01:30.890
and it's a lot about trying to build off
00:01:30.890 --> 00:01:34.330
of each other's ideas and
bounce ideas off of each other
00:01:34.330 --> 00:01:38.510
and build upon ideas that
have already been made
00:01:38.510 --> 00:01:40.260
by people decades ago.
00:01:40.260 --> 00:01:43.820
And I think that the facts
that we all come with it,
00:01:43.820 --> 00:01:46.717
with our own perspectives
and different ideas
00:01:46.717 --> 00:01:49.990
and different ways of being creative,
00:01:49.990 --> 00:01:52.330
allows math to advance further.
00:01:52.330 --> 00:01:55.080
Because we can all
combine our creative ideas
00:01:55.080 --> 00:01:56.270
into something bigger.
00:01:56.270 --> 00:01:58.603
- We collect data on everything.
00:01:59.690 --> 00:02:03.810
The ability to use that
data in a smart, safe,
00:02:03.810 --> 00:02:07.120
and efficient way depends
on new applications
00:02:07.120 --> 00:02:08.490
of mathematical concepts
00:02:08.490 --> 00:02:11.143
to these new and innovative data sets.
00:02:12.180 --> 00:02:13.470
As we get to that point,
00:02:13.470 --> 00:02:16.400
we'll start to be thinking
outside the box a lot more
00:02:16.400 --> 00:02:19.870
and we'll be a much more
innovative digital society.
00:02:19.870 --> 00:02:22.610
But that can't happen unless
we start trying to be creative
00:02:22.610 --> 00:02:25.204
and not just rely on tried and true.
00:02:25.204 --> 00:02:26.552
(typewriter typing)
00:02:26.552 --> 00:02:29.580
(light music continues)
00:02:29.580 --> 00:02:31.440
- Creativity's really important for me
00:02:31.440 --> 00:02:33.840
as a future job, as a
part of my future job.
00:02:33.840 --> 00:02:37.610
I would want to do something that changes
00:02:37.610 --> 00:02:40.680
and then I can use
problem-solving skills constantly.
00:02:40.680 --> 00:02:42.620
I feel like when I make animations
00:02:42.620 --> 00:02:45.510
or when I figure out how
to explain something,
00:02:45.510 --> 00:02:48.040
I am really, I love that,
00:02:48.040 --> 00:02:50.420
because it's, there's so
many different solutions,
00:02:50.420 --> 00:02:53.010
but knowing that you can
try to find and experiment
00:02:53.010 --> 00:02:55.840
with different ones and maybe
create something beautiful
00:02:55.840 --> 00:02:59.220
is really, I don't know, inspiring to me.
00:02:59.220 --> 00:03:01.980
- Mathematigals is an
educational initiative
00:03:01.980 --> 00:03:03.110
that I co-founded
00:03:03.110 --> 00:03:05.960
with a fellow mathematician,
Jess Williams,
00:03:05.960 --> 00:03:08.530
and what we're trying
to do is make maths fun
00:03:08.530 --> 00:03:10.900
and accessible and encourage more girls
00:03:10.900 --> 00:03:13.870
to pursue careers in maths.
00:03:13.870 --> 00:03:15.810
Creativity is essential here
00:03:15.810 --> 00:03:17.670
because we're trying to think of ways
00:03:17.670 --> 00:03:20.620
that people will enjoy maths
00:03:20.620 --> 00:03:23.400
and it will be fun and accessible to them.
00:03:23.400 --> 00:03:25.780
Different creative techniques
that we've been using
00:03:25.780 --> 00:03:28.980
are trying to present
mathematical problems
00:03:28.980 --> 00:03:31.980
in fun, short videos
00:03:31.980 --> 00:03:34.280
and that explain the problem in a way
00:03:34.280 --> 00:03:36.100
that everybody will understand
00:03:36.100 --> 00:03:38.170
and will make them want to learn more
00:03:38.170 --> 00:03:41.140
and discover more about the
topics that we're talking about.
00:03:41.140 --> 00:03:46.140
- I'm really lucky that I
get to be creative every day
00:03:46.140 --> 00:03:49.300
in my work and I have been
since I got into this field
00:03:49.300 --> 00:03:50.460
of data science.
00:03:50.460 --> 00:03:54.340
In general, across the last
decade, my work has really been
00:03:54.340 --> 00:03:58.530
about designing and
testing innovative ways
00:03:58.530 --> 00:04:01.833
to capture human behavior
within game-based assessments.
00:04:02.860 --> 00:04:04.160
My collaborators and I,
00:04:04.160 --> 00:04:07.170
from the time I was in
graduate school to now,
00:04:07.170 --> 00:04:09.460
use a variety of different
modeling techniques
00:04:09.460 --> 00:04:10.440
from various fields.
00:04:10.440 --> 00:04:12.910
We'll pull things from engineering,
00:04:12.910 --> 00:04:16.880
aerospace, more basic mathematical models,
00:04:16.880 --> 00:04:18.710
to help us achieve this goal.
00:04:18.710 --> 00:04:20.330
We get to think outside the box.
00:04:20.330 --> 00:04:23.360
We get to think about how we
can pull in different types
00:04:23.360 --> 00:04:24.940
of thinking from different fields
00:04:24.940 --> 00:04:28.370
to help us better
understand human behavior,
00:04:28.370 --> 00:04:30.463
human cognition, learning.
00:04:31.800 --> 00:04:33.840
It's really exciting and really novel,
00:04:33.840 --> 00:04:35.090
and it's something that,
00:04:35.090 --> 00:04:36.610
because of the field that I'm in,
00:04:36.610 --> 00:04:39.556
I've been able to do this
now for multiple years.
00:04:39.556 --> 00:04:41.632
(typewriter typing)
00:04:41.632 --> 00:04:44.460
(light music continues)
00:04:44.460 --> 00:04:45.883
- Whenever I wanna have,
00:04:46.770 --> 00:04:49.500
come up with a solution to a
problem and I don't have it,
00:04:49.500 --> 00:04:54.270
my immediate reaction is to
go outside and go on a walk.
00:04:54.270 --> 00:04:56.420
I love walking in all kinds of weather.
00:04:56.420 --> 00:04:59.430
It's kind of, it's just,
00:04:59.430 --> 00:05:01.510
I feel like with the peace and calm,
00:05:01.510 --> 00:05:05.260
moving away from the problem
and stepping away from it,
00:05:05.260 --> 00:05:09.350
sometimes I get way better
ideas and it inspires me.
00:05:09.350 --> 00:05:10.720
But I also think there's
something to be said
00:05:10.720 --> 00:05:13.560
about not being inspired.
00:05:13.560 --> 00:05:15.260
Not always is amazing. (laughing)
00:05:15.260 --> 00:05:18.940
I feel like sometimes I
get struck with inspiration
00:05:18.940 --> 00:05:22.060
for how I want to explain
a Khan Academy video
00:05:22.060 --> 00:05:23.880
or how I wanna approach a piece of art
00:05:23.880 --> 00:05:27.000
or how I want to approach a math problem.
00:05:27.000 --> 00:05:28.820
But sometimes, it doesn't come.
00:05:28.820 --> 00:05:30.990
So I feel like what the best solution is
00:05:30.990 --> 00:05:32.920
when you are trying to get
into that creative zone
00:05:32.920 --> 00:05:34.820
and you can't is to just do it
00:05:34.820 --> 00:05:38.089
and try to do something anyway.
00:05:38.089 --> 00:05:41.120
Write something or write your equations.
00:05:41.120 --> 00:05:42.540
Try to figure it out.
00:05:42.540 --> 00:05:44.770
And if you make mistakes, that's okay.
00:05:44.770 --> 00:05:45.980
Because it's something to jump off of,
00:05:45.980 --> 00:05:49.370
and maybe, sometimes seeing
what you already know
00:05:49.370 --> 00:05:52.200
down on paper can help you
come up with better ideas
00:05:52.200 --> 00:05:53.860
and could help you be more creative.
00:05:53.860 --> 00:05:56.170
- Forcing yourself to
just conjure a solution
00:05:56.170 --> 00:05:57.520
simply does not work.
00:05:57.520 --> 00:05:59.310
Instead, take a break from a task.
00:05:59.310 --> 00:06:01.730
Pick something else up,
like a physical sport
00:06:01.730 --> 00:06:03.150
or even video games.
00:06:03.150 --> 00:06:05.210
And then come back to
the original problem.
00:06:05.210 --> 00:06:06.665
That can do wonders.
00:06:06.665 --> 00:06:08.490
(typewriter typing)
00:06:08.490 --> 00:06:11.823
(light music continues)
00:06:13.647 --> 00:06:17.100
- One of my biggest passions
is documentary filmmaking.
00:06:17.100 --> 00:06:19.390
I've been making videos
since I was in middle school.
00:06:19.390 --> 00:06:23.440
And I remember being, it
was always a challenge,
00:06:23.440 --> 00:06:25.070
because sometimes I wanted to do things,
00:06:25.070 --> 00:06:27.220
but I didn't have the equipment to do it.
00:06:27.220 --> 00:06:30.680
I really wanted to record
myself in a certain way,
00:06:30.680 --> 00:06:33.810
but there was no way for
anyone to hold the microphone,
00:06:33.810 --> 00:06:37.190
or I didn't have a dolly or
any expensive camera equipment.
00:06:37.190 --> 00:06:40.230
So, I remember,
00:06:40.230 --> 00:06:41.440
I think the most important thing to do
00:06:41.440 --> 00:06:43.200
is just use what you have.
00:06:43.200 --> 00:06:47.040
I would tape a cross-country
ski pole to my ceiling
00:06:47.040 --> 00:06:49.210
and hold the microphone that way.
00:06:49.210 --> 00:06:52.160
Or I would put a pillow in a box
00:06:52.160 --> 00:06:54.270
and then speak into the
microphone with that
00:06:54.270 --> 00:06:56.460
as my makeshift sound studio
00:06:56.460 --> 00:07:01.460
or make a tripod out of a pile of books.
00:07:01.460 --> 00:07:04.870
And I feel like it's
kinda the same with math.
00:07:04.870 --> 00:07:08.150
You are, sometimes, you
don't know how to solve
00:07:08.150 --> 00:07:10.100
a really big problem,
00:07:10.100 --> 00:07:12.730
and you only have all the
tools you've been taught
00:07:12.730 --> 00:07:13.880
up to that point.
00:07:13.880 --> 00:07:16.999
And maybe there is a
fancier way of getting
00:07:16.999 --> 00:07:19.180
to the solution, but a lotta the time,
00:07:19.180 --> 00:07:21.780
it's just about combining
things that you already have
00:07:21.780 --> 00:07:24.090
in your, that you've already learned,
00:07:24.090 --> 00:07:25.550
and coming up with a solution that way.
00:07:25.550 --> 00:07:29.250
And sometimes, that comes
up with some really creative
00:07:29.250 --> 00:07:32.332
and unexpected solutions to problems.
00:07:32.332 --> 00:07:33.610
(typewriter typing)
00:07:33.610 --> 00:07:36.210
(light music continues)
00:07:36.210 --> 00:07:39.830
- Algebra is really the unifying thread
00:07:39.830 --> 00:07:42.460
of almost all of mathematics.
00:07:42.460 --> 00:07:44.370
You may think algebra is boring,
00:07:44.370 --> 00:07:47.300
but it is the one tool you can use
00:07:47.300 --> 00:07:50.950
to not only understand
but unlock the universe.
00:07:50.950 --> 00:07:54.190
Creative algebra is used
in computer game design.
00:07:54.190 --> 00:07:58.170
It powers how artificial
intelligence works.
00:07:58.170 --> 00:08:00.340
Mastering algebra will provide you
00:08:00.340 --> 00:08:02.710
with the ability to decode and understand
00:08:02.710 --> 00:08:04.680
many complex systems.
00:08:04.680 --> 00:08:07.490
In my opinion, if you can master algebra,
00:08:07.490 --> 00:08:08.838
you can master anything.
00:08:08.838 --> 00:08:12.142
(light music continues)
|
The future of creativity in algebra | https://www.youtube.com/watch?v=Q-apRGBr3Xg | vtt | https://www.youtube.com/api/timedtext?v=Q-apRGBr3Xg&ei=uVWUZaWKEd6XhcIP-JSKoAQ&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245289&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=C2E243A0A31BEDF67C30C40D08F44B3C0FAA5F56.A71771D9CA5BE0779C641B90505EAF67EA586679&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.320 --> 00:00:02.903
(upbeat music)
00:00:11.990 --> 00:00:13.850
- Hi everyone, Sal Khan here.
00:00:13.850 --> 00:00:16.090
If you look at most of human history,
00:00:16.090 --> 00:00:20.400
the top artists, the top
musicians were also mathematicians
00:00:20.400 --> 00:00:23.600
and also scientists and also engineers.
00:00:23.600 --> 00:00:28.160
And this convergence between
creativity and mathematics
00:00:28.160 --> 00:00:31.820
and science and engineering
is only accelerating.
00:00:31.820 --> 00:00:35.370
In the careers of the future,
algebra and creativity
00:00:35.370 --> 00:00:37.720
are gonna be that much more empowering,
00:00:37.720 --> 00:00:39.070
but don't take my word for it.
00:00:39.070 --> 00:00:41.030
You're about to meet
some of my close friends
00:00:41.030 --> 00:00:42.870
who can better draw that link
00:00:42.870 --> 00:00:47.123
between algebra and creativity
and the work of the future.
00:00:47.123 --> 00:00:49.790
(upbeat music)
00:00:53.017 --> 00:00:55.240
- The math underpins
everything in our universe,
00:00:55.240 --> 00:00:58.800
so it impacts every corner of our society.
00:00:58.800 --> 00:01:00.990
But over the past decade in particular,
00:01:00.990 --> 00:01:03.450
the advances in computer technology
00:01:03.450 --> 00:01:05.640
and introduction of machine learning
00:01:05.640 --> 00:01:08.930
and artificial intelligence
has been massive
00:01:08.930 --> 00:01:10.730
and we're only learning more and more
00:01:10.730 --> 00:01:12.910
and building better and better systems,
00:01:12.910 --> 00:01:15.150
and math underpins all of that
00:01:15.150 --> 00:01:17.910
and it's fundamental to
all of those systems.
00:01:17.910 --> 00:01:21.840
And in fact, computer science
is inherently linear algebra,
00:01:21.840 --> 00:01:25.730
so it's really foundational
to those scientific advances.
00:01:25.730 --> 00:01:29.000
- One relatively recent
example that really inspired me
00:01:29.000 --> 00:01:31.330
was the first real photo that scientists
00:01:31.330 --> 00:01:34.100
were able to capture of a black hole,
00:01:34.100 --> 00:01:37.360
the mysterious remnants of giant stars
00:01:37.360 --> 00:01:40.140
that lurk all over the universe.
00:01:40.140 --> 00:01:42.410
And it's the way that
scientists used creativity
00:01:42.410 --> 00:01:45.690
and math to solve the problem
that was so fascinating.
00:01:45.690 --> 00:01:47.780
You see, these black holes are so distant
00:01:47.780 --> 00:01:49.870
that there is no single telescope
00:01:49.870 --> 00:01:52.680
that is large enough to be
able to actually see them.
00:01:52.680 --> 00:01:55.560
And the scientists came
up with this clever idea,
00:01:55.560 --> 00:01:58.290
creating a network of small telescopes
00:01:58.290 --> 00:02:01.000
distributed all across the
globe that were synchronized
00:02:01.000 --> 00:02:05.280
to capture and focus the
same object at the same time
00:02:05.280 --> 00:02:08.130
creating a giant virtual telescope.
00:02:08.130 --> 00:02:10.800
Now the aperture of this
giant virtual telescope
00:02:10.800 --> 00:02:15.150
is nearly the same size as
a diameter of the Earth.
00:02:15.150 --> 00:02:17.520
And with that in place, the
scientists and engineers
00:02:17.520 --> 00:02:20.230
were able to capture all
the bits and pieces of data
00:02:20.230 --> 00:02:22.690
and put it all together
into the first image
00:02:22.690 --> 00:02:25.810
of a black hole that is
53 million light years,
00:02:25.810 --> 00:02:30.060
which is 318 quintillion miles away.
00:02:30.060 --> 00:02:33.384
Now that's an impressive
use of creativity and math.
00:02:33.384 --> 00:02:36.051
(upbeat music)
00:02:38.880 --> 00:02:41.540
- In the future, in
order to add innovation,
00:02:41.540 --> 00:02:42.730
students are gonna need skills
00:02:42.730 --> 00:02:44.900
such as creative problem solving,
00:02:44.900 --> 00:02:48.370
so not looking at things
from the same perspective,
00:02:48.370 --> 00:02:51.060
being able to ideate, so
come up with new ideas
00:02:51.060 --> 00:02:52.610
and divergent thinking, right,
00:02:52.610 --> 00:02:54.290
the ability to come up with ideas
00:02:54.290 --> 00:02:57.350
that are drastically
different from each other.
00:02:57.350 --> 00:02:59.320
Beyond creative problem
solving, students will also
00:02:59.320 --> 00:03:01.600
need to show adaptability.
00:03:01.600 --> 00:03:03.730
So the ability to pivot as the world
00:03:03.730 --> 00:03:06.430
and constraints around us kind of pivot.
00:03:06.430 --> 00:03:08.890
The STEM field is constantly evolving
00:03:08.890 --> 00:03:10.790
and it's growing as we
gain more knowledge,
00:03:10.790 --> 00:03:13.100
so students' ability to
be creative and adapt
00:03:13.100 --> 00:03:16.470
as the field adapts will
be critical for success,
00:03:16.470 --> 00:03:18.780
and for the ability to
innovate as we move forward.
00:03:18.780 --> 00:03:20.410
- Communication skills are always
00:03:20.410 --> 00:03:23.570
going to be essential for
furthering innovation.
00:03:23.570 --> 00:03:25.490
And this is because if you want to make
00:03:25.490 --> 00:03:27.650
a scientific advancement, you have to have
00:03:27.650 --> 00:03:29.260
a lot of people on your side.
00:03:29.260 --> 00:03:31.370
So you have to have funding bodies,
00:03:31.370 --> 00:03:33.210
you have to have other scientists,
00:03:33.210 --> 00:03:36.190
you have to have people
interested in what you're doing.
00:03:36.190 --> 00:03:39.110
So this means you have to
have the communication tools
00:03:39.110 --> 00:03:43.730
to communicate with all of
those different areas of people.
00:03:43.730 --> 00:03:45.870
So different ways that you
can learn to communicate
00:03:45.870 --> 00:03:48.790
with them are through
things like presentations,
00:03:48.790 --> 00:03:51.840
through visual aids, through videos.
00:03:51.840 --> 00:03:54.550
When you're preparing for
communication tools of the future,
00:03:54.550 --> 00:03:57.600
it's quite difficult to
know what those will be.
00:03:57.600 --> 00:04:00.210
So if we think back to 10 years ago,
00:04:00.210 --> 00:04:02.460
we didn't have things like TikTok,
00:04:02.460 --> 00:04:04.100
which is now a huge avenue
00:04:04.100 --> 00:04:06.960
for communicating things to young people.
00:04:06.960 --> 00:04:09.310
So that is something that
we've had to adapt to
00:04:09.310 --> 00:04:12.300
and to learn and tailor our communication
00:04:12.300 --> 00:04:15.640
during this new area of media.
00:04:15.640 --> 00:04:18.900
So having versatility,
if students are able
00:04:18.900 --> 00:04:21.780
to take the skills that
they have and apply them
00:04:21.780 --> 00:04:24.890
to new areas of communication,
they'll be prepared
00:04:24.890 --> 00:04:27.058
for the communication tools of the future.
00:04:27.058 --> 00:04:29.725
(upbeat music)
00:04:33.357 --> 00:04:35.210
- There are so many
ways that you can expand
00:04:35.210 --> 00:04:37.280
your creative and math skills without even
00:04:37.280 --> 00:04:38.730
really realizing that you're doing it.
00:04:38.730 --> 00:04:42.510
Like for me, I'm a big board game fan,
00:04:42.510 --> 00:04:44.840
and I realized that there's so many games
00:04:44.840 --> 00:04:49.740
that involve math and learning
how to solve problems.
00:04:49.740 --> 00:04:54.150
And sometimes just when you're cooking.
00:04:54.150 --> 00:04:56.940
I love to bake, and so I
feel like I'm constantly
00:04:56.940 --> 00:05:01.040
using fractions and learning
how to do proportions,
00:05:01.040 --> 00:05:02.650
just because I'm doing things that I love.
00:05:02.650 --> 00:05:05.060
So I feel like the best way to expand
00:05:05.060 --> 00:05:07.410
your mathematical and creative skills
00:05:07.410 --> 00:05:09.220
are just doing what you love to do,
00:05:09.220 --> 00:05:12.503
because probably it has
some kind of math in it,
00:05:12.503 --> 00:05:14.680
and some kind of creativity.
00:05:14.680 --> 00:05:17.970
- Try to connect what you're
learning to your real life.
00:05:17.970 --> 00:05:20.560
It's really easy to be in the classroom
00:05:20.560 --> 00:05:23.280
and think that it's
siloed, and it's orthogonal
00:05:23.280 --> 00:05:25.300
from the world around you.
00:05:25.300 --> 00:05:27.870
The more we can connect
what we're learning
00:05:27.870 --> 00:05:29.790
in the classroom to our real life,
00:05:29.790 --> 00:05:32.410
whether it be sports or entertainment,
00:05:32.410 --> 00:05:36.070
politics, news, whatever,
the connection that you make
00:05:36.070 --> 00:05:38.220
between math and your real
life will really help you
00:05:38.220 --> 00:05:40.590
appreciate the skills and the methods
00:05:40.590 --> 00:05:42.530
and find ways to transfer them
00:05:42.530 --> 00:05:45.229
outside of just the classroom alone.
00:05:45.229 --> 00:05:47.896
(upbeat music)
00:05:51.300 --> 00:05:54.240
- One of the newest ways of
thinking about problem solving
00:05:54.240 --> 00:05:58.970
for me is something that my
math professor would tell me.
00:05:58.970 --> 00:06:02.450
He would say, "Don't
be afraid to be stuck."
00:06:02.450 --> 00:06:06.760
And I think that a lot of the
time when we are doing math
00:06:06.760 --> 00:06:10.200
and we get stuck, sometimes it can be,
00:06:10.200 --> 00:06:12.980
you can feel like, "Wow,
this is a reflection of me
00:06:12.980 --> 00:06:14.570
and my mathematical abilities.
00:06:14.570 --> 00:06:16.660
Wow, maybe I shouldn't be doing math."
00:06:16.660 --> 00:06:20.100
But really a lot of the
time, it's just an indication
00:06:20.100 --> 00:06:23.010
that you need to spend
more time doing the math
00:06:23.010 --> 00:06:25.150
or figuring out what
the problem is exactly.
00:06:25.150 --> 00:06:26.600
If you haven't gotten stuck yet,
00:06:26.600 --> 00:06:30.310
then you probably will
get stuck at some point.
00:06:30.310 --> 00:06:33.220
So being stuck is just a part of math
00:06:33.220 --> 00:06:36.970
and it's kind of learning what to do
00:06:36.970 --> 00:06:39.817
when you are stuck is a really big part
00:06:40.954 --> 00:06:42.320
of being creative in math,
00:06:42.320 --> 00:06:44.980
and being able to solve
problems in the future.
00:06:44.980 --> 00:06:49.690
- One example that I often use is I often
00:06:49.690 --> 00:06:54.690
try to solve problems both in
the traditional algebraic way
00:06:56.670 --> 00:07:01.670
but I also try to visualize
problems in 2D and 3D space
00:07:02.870 --> 00:07:04.210
to solve them more visually.
00:07:04.210 --> 00:07:07.440
And so I think the more ways that you can
00:07:07.440 --> 00:07:09.840
figure out how to solve a problem,
00:07:09.840 --> 00:07:12.380
the more ways that you
can eventually sort of
00:07:12.380 --> 00:07:15.100
save in your toolbox and use later on
00:07:15.100 --> 00:07:17.260
to solve other problems.
00:07:17.260 --> 00:07:19.950
- There's lots of different
tools and resources
00:07:19.950 --> 00:07:23.410
like apps and puzzle games
that are gonna help you
00:07:23.410 --> 00:07:25.350
think about problems in new ways
00:07:25.350 --> 00:07:27.850
and help develop that critical thinking
00:07:27.850 --> 00:07:30.470
that you need to be able
to apply your skills
00:07:30.470 --> 00:07:32.780
to a lot of different areas.
00:07:32.780 --> 00:07:35.150
And sometimes even starting at the answer
00:07:35.150 --> 00:07:37.450
and working backwards through the problem
00:07:37.450 --> 00:07:40.980
can help you see a different
way of getting to the answer.
00:07:40.980 --> 00:07:42.250
- Students can combine new ways
00:07:42.250 --> 00:07:43.670
of thinking about problem solving
00:07:43.670 --> 00:07:45.440
by trying to look at it
from different angles.
00:07:45.440 --> 00:07:47.200
Anytime you approach a problem,
00:07:47.200 --> 00:07:49.720
If you're just looking at
it from your perspective,
00:07:49.720 --> 00:07:52.940
you're not gonna get a holistic
view of the solution space.
00:07:52.940 --> 00:07:56.390
So try to have perspectives
and look at the problem
00:07:56.390 --> 00:07:58.760
from multiple angles to understand
00:07:58.760 --> 00:08:00.610
all the ways in which it could be viewed.
00:08:00.610 --> 00:08:02.810
The more holistically you view a problem,
00:08:02.810 --> 00:08:05.100
the more paths you look
at, the more efficient
00:08:05.100 --> 00:08:07.300
and effective you're
gonna be at solving it.
00:08:08.393 --> 00:08:11.060
(upbeat music)
00:08:13.600 --> 00:08:15.640
- One of these that is
most interesting to me
00:08:15.640 --> 00:08:18.840
is the field of robotics
and the different ways
00:08:18.840 --> 00:08:22.220
machine learning will impact our society.
00:08:22.220 --> 00:08:25.670
So robotics combines lots
of math, lots of science,
00:08:25.670 --> 00:08:29.340
lots of technology, but
also socioeconomic factors
00:08:29.340 --> 00:08:31.700
such as human and robot trust.
00:08:31.700 --> 00:08:35.700
So how humans feel about
robots, how they trust them,
00:08:35.700 --> 00:08:37.960
and human/robot teams in the workplace,
00:08:37.960 --> 00:08:42.800
so how humans and robots work
together to accomplish a task.
00:08:42.800 --> 00:08:45.550
And creativity will be
hugely important here,
00:08:45.550 --> 00:08:47.990
so creativity is not
only gonna be important
00:08:47.990 --> 00:08:49.450
in designing the robots,
00:08:49.450 --> 00:08:52.880
they're very intricate,
very complex systems,
00:08:52.880 --> 00:08:55.010
and it'll require creativity to know
00:08:55.010 --> 00:08:58.040
exactly how to design
them to do their jobs,
00:08:58.040 --> 00:09:01.060
but also how to integrate
them into our everyday lives
00:09:01.060 --> 00:09:04.560
which is a total different
facet of creativity.
00:09:04.560 --> 00:09:06.540
And it's actually a new way of thinking
00:09:06.540 --> 00:09:08.740
because it hasn't really been done yet.
00:09:08.740 --> 00:09:10.747
So even though there are robots around us
00:09:10.747 --> 00:09:13.070
and we've seen them, you've got the Roomba
00:09:13.070 --> 00:09:15.210
who hoovers your living room,
00:09:15.210 --> 00:09:18.420
really where we're heading is
for robots to be everywhere
00:09:18.420 --> 00:09:20.980
and to be a really integral
part of our society.
00:09:20.980 --> 00:09:24.340
So preparing for that
change and using creativity
00:09:24.340 --> 00:09:25.990
to figure out the best way to do that
00:09:25.990 --> 00:09:29.078
will be a really important step
in innovation in the future.
00:09:29.078 --> 00:09:31.745
(upbeat music)
|
Creativity in biology | https://www.youtube.com/watch?v=OX0zcM1Bwuw | vtt | https://www.youtube.com/api/timedtext?v=OX0zcM1Bwuw&ei=uVWUZdH9FuCJp-oP-ZCIuAE&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245289&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=8A0593EFA96D19A9A7573A99164FC250BCD1F57B.915C985FB13A32C51F3009A8A9BE4BD92F4BB94F&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
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Language: en
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(gentle rock music)
(marker scratches)
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- Hi, everyone, Sal Khan here.
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Biology is the study of living systems,
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and you can look all around you
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and even at yourself to
recognize that living systems
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and biology
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and nature is fundamentally creative.
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And for us to understand it,
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we have to be even more creative.
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But don't take my word for it.
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I'm gonna introduce you to some
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of my close friends
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who can even better draw
this link between biology
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and creativity.
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(keyboard keys clicking)
(marker scratching)
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- Creativity is super important in biology
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because it's hugely important
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(keyboard keys clicking)
in the process of evolution.
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Evolution often takes a winding path
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to get to what we see now,
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and if we wanna follow this path
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in an attempt to understand it,
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sometimes we've gotta be as resourceful
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and clever as evolution has been.
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That requires creativity
in how we solve problems,
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and even creativity in
the questions we ask.
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- Creativity is so important
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for anybody who is thinking
(keyboard keys clicking)
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about, who is studying biology.
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Because the question we're
trying to understand is not
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just, take in all the information
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that we know about biology.
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We want people to imagine what biology,
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what the natural world,
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what the physical world, you know,
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what our bodies can actually do,
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what our brains can do.
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And to be able to do that,
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you need to think out of
the box, you need to think
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about things that haven't
been thought about before,
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and that is why biology,
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that is why creativity is so critical
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for anybody studying biology.
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- Creativity isn't
exclusive just to the arts,
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but it also spans into science
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(keyboard keys clicking)
and technology
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and engineering
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and mathematics.
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Creativity
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and science comes down to,
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thinking about a problem or a situation,
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and how best to approach that problem
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or situation from multiple angles.
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So, when you approach a
problem in the real world,
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it won't be multiple choice,
like you may have in school.
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It actually would be
something that requires you
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to think about that particular situation,
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and apply other things you've learned
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about it to be creative,
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and to come up with answers
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that may not have been
familiar to you before.
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(keyboard keys clicking)
(marker scratching)
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- One question that people ask me is,
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how do I apply creativity
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to the presentations
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(keyboard keys clicking)
that I give?
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And my secret sauce is to come up
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with a visual image that anybody,
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I don't if you're the adult,
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whether you're a fifth
grader or second grader,
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that you can grasp that concept.
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And here's my favorite one.
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So every single time you move your body,
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there's whole bunches of neurochemicals
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that are released in your brain.
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And you've heard of these
neurochemicals: dopamine,
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noradrenaline, serotonin.
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And so, that's the fact,
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but the image that I give is
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that every single time you move your body,
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it's like giving your brain
a wonderful bubble bath
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of neurochemicals that enrich your brain,
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that change that neurochemical milieu,
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and that is the image
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that everybody that comes
to my talks leaves with,
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and inspires them a little bit
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(gentle electronic music)
to move their body more.
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So can you come up with that image,
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that playful, fun,
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but factually accurate image
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that conveys your message.
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That will be your secret sauce too.
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- Have you heard that the
bees aren't doing great?
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Well, I've been studying that,
(keyboard keys clicking)
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and trying to understand
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how their complex health issues connect
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to a curious little parasite
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that's in nearly every
honeybee colony worldwide.
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It's called Varroa Destructor, by the way.
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Now, before I started this study,
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we thought the that it was an open
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and shut case, that the
parasite was sucking
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out the bee's blood, sort
of like a tick on a puppy,
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but I thought something more
strange might be going on.
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The damage that it caused just didn't seem
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like the damage that would
be caused by blood removal.
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The feeding process is super
difficult to see though,
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so, I had this idea.
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I fed different color
glowing food to the bees
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in their pollen
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and their sugar water,
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to color their organs specific colors.
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Then, when the parasite fed on the bees,
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I could tell which organ it was eating,
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based on which color was
in its digestive system,
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and it turns out that they
were eating the bee's liver,
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by the way, which is pretty weird,
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but, this kind of work
is actually pretty fun.
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And it was definitely a place
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where creativity was rewarded in biology.
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(keyboard keys clicking)
(marker scratching)
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Some of the world's greatest
discoveries have been reached
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by applying creative thinking
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(keyboard keys clicking)
to scientific questions.
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Here's a good example.
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I have been super
inspired by the creativity
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of the Geiger-Marsden
gold foil experiments,
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since I was in high school.
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They have helped us understand
the structure of an atom,
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and atoms make up pretty much everything
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we can interact with,
biological or otherwise.
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Like, you can't see an atom,
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so, you've gotta get
creative to figure out
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how its pieces are all laid out.
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We used to think
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that its positive charge was
pretty evenly spread out,
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but this research team fired a beam
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of positively charged
particles at gold atoms,
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and found that a bunch
of them bounced off,
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while even more of them
passed straight through.
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And this suggested that
the positive charge
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in the atom was concentrated
in a small part,
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because some of the positive
particles were upheld,
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like the two positive poles
of like, two separate magnets,
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but much of the rest of the
atom must be empty space,
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because a bunch of the
particles passed right through.
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Because of this absolutely genius way
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of visualizing what we can't see,
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we now know the structure of the stuff
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that makes up the observable universe.
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(upbeat synthpop music)
And, because
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of this pioneering research,
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we've got everything from nuclear power
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to MRI machines, even the
life saving technology
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that's inside of the smoke
detectors in your home.
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(keyboard keys clicking)
(marker scratching)
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So, the first step discoveries
is always the same.
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(keyboard keys clicking)
Figure out your question.
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Maybe you wanna know where
fireflies go during the day,
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or how mosquitoes find people to bite.
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And then you should create a hypothesis.
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Maybe mosquitoes find people
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by following the smell of sweat
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and their breath, then
consider what must be true
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for your hypothesis to be true.
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You might not be able to test a mosquito's
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smell receptors directly, but
if your hypothesis is true,
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people who are exercising,
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and thus exhaling a lot,
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and producing more sweat,
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should attract more mosquitoes.
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Actually, I probably
shouldn't encourage you
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to experiment on humans.
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Why don't you maybe try the
firefly question instead?
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- Young people can get
creative in science,
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(keyboard keys clicking)
by using not just science
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but other things that they're learning
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from their life,
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and connecting it to science
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or connecting science to other things
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in their life such as art,
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and other things that are outside
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of the traditional STEM fields.
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For example, when you're looking at,
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or wondering about how something works,
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like an mRNA vaccine, or
how the organ systems work,
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you can use other aspects of your life,
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and learn to make, or draw analogies
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between different systems.
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That's a really important
aspect of being creative
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and using critical thinking,
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because a lot of systems are similar
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to other systems, even though
they use different names
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or look very different,
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and you can expand on your knowledge
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on something by being creative,
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or using other things outside of science
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to draw connections
between different fields
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and different things.
|
Creative biology at work | https://www.youtube.com/watch?v=XMXmY11vDDA | vtt | https://www.youtube.com/api/timedtext?v=XMXmY11vDDA&ei=uVWUZbuQKNvTxN8Pju-O-Ao&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245289&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=A89FE119AAE8F4B534730E451D3068EC3BA382B4.144F480E45BE6946A0FF301DE9BC83699CED90E9&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
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(upbeat music)
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- Hi everyone, Sal Khan here.
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From finding novel cures for
a seemingly incurable disease
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to diagnosing what's going on with someone
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if you're a physician or a nurse,
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you can imagine there is
incredible creativity in biology.
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And don't take my word for it.
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You're now going to
meet some of my friends
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who can tell you more
about that connection
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between biology and creativity.
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- All science careers involve creativity,
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think about it.
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We're asking and answering questions,
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and we're solving the world's problems.
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So the more creatively we can
solve the world's problems,
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the more new ideas and
concepts and approaches
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we can use to address
the world's problems,
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the better off we'll be.
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- Creativity is the guiding force
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on the path to good science.
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So there isn't a science job out there
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that doesn't benefit from creativity.
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Like you could be an engineer,
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building more efficient transistors
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for tinier and tinier phones.
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You could be a climate scientist
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figuring out how we can
reduce our carbon footprint
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and save the world from
climate catastrophe,
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or an agricultural researcher
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deducing efficient ways
to feed the planet,
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or maybe, an entomologist like me,
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understanding how relationships
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between organisms keep us all healthy.
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Creativity is important
in all of these careers.
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- One really cool job is
working for a science museum.
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And so the people who are
like the chief directors
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or bioscientists, or what
have you for science museums
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usually have a biology or a
science background of some kind,
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maybe have gone through even being a PhD
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or a post doctoral fellow.
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And their job is to design
exhibits for visitors to museums
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and come up with engaging ways
to share ideas in science.
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And so I just think
that's a really cool job
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that you might not immediately think of.
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(upbeat music)
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- As we move forward,
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as scientists, as biologists,
the old adage is true.
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A picture is worth a thousand words.
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So what is that image, that graph,
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that graphic, or even that imagery
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that really gets to the core of your idea?
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It almost gets to advertising.
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You want that image to stick
in your listener's minds.
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That both lets them understand
00:03:01.320 --> 00:03:05.400
the undeniably complex concept
that you're trying to convey,
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but also makes it memorable.
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And developing that skill
to come up with that picture
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that is truly worth a thousand words
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is going to be the skill
that we will all need
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going into the future.
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- Creativity plays a role in my life
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pretty much every single day,
00:03:25.890 --> 00:03:27.780
by reminding me not to stop
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just because I've reached a setback.
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Like hitting a wall as
you're moving towards a goal
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doesn't have to be the end for that goal.
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To me, it just means
that the path to success
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isn't gonna be quite as straightforward
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as I originally thought.
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Like, the way around
that wall may require me
00:03:43.920 --> 00:03:46.590
to climb over it, or tunnel under it,
00:03:46.590 --> 00:03:49.220
or maybe even dig straight through it.
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But if I'm creative enough,
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I can probably find a way
to get to the other side.
00:03:54.420 --> 00:03:56.490
And this plays out for me in the lab,
00:03:56.490 --> 00:03:58.740
literally every single day.
00:03:58.740 --> 00:04:01.520
It fuels tenacity that can see you
00:04:01.520 --> 00:04:02.930
through things like graduate school
00:04:02.930 --> 00:04:04.730
if you ever choose to go that route.
00:04:09.280 --> 00:04:11.220
- I allow my brain to do the work
00:04:11.220 --> 00:04:13.510
to get into my creative zone.
00:04:13.510 --> 00:04:15.810
When I have a problem to resolve,
00:04:15.810 --> 00:04:17.260
sometimes I just sleep on it
00:04:17.260 --> 00:04:20.880
and I let my subconscious mind work
00:04:20.880 --> 00:04:24.730
through resolving problems,
and solving problems.
00:04:24.730 --> 00:04:29.027
Our brains are always at
work like trying defragment
00:04:30.590 --> 00:04:33.620
and break apart the
things that we encounter.
00:04:33.620 --> 00:04:36.680
So I spend a little time thinking
00:04:36.680 --> 00:04:40.050
about how I can approach
things creatively.
00:04:40.050 --> 00:04:42.790
And then, I spend a
little time not thinking
00:04:42.790 --> 00:04:45.350
about those things and allowing my brain,
00:04:45.350 --> 00:04:48.480
and my subconscious mind
to have an opportunity
00:04:48.480 --> 00:04:50.010
to do the work for me.
00:04:50.010 --> 00:04:52.560
A lot of times when I
come back afterwards,
00:04:52.560 --> 00:04:53.870
I've got a great idea.
00:04:53.870 --> 00:04:57.460
I've got the answers, and
I have new ways to solve
00:04:57.460 --> 00:05:00.040
and resolve things that
I've been thinking about.
00:05:00.040 --> 00:05:02.020
- To get into my creative zone,
00:05:02.020 --> 00:05:03.910
I do something that I'd like to call
00:05:03.910 --> 00:05:06.110
productive procrastination.
00:05:06.110 --> 00:05:09.340
I start what I'm working
on way before it's due,
00:05:09.340 --> 00:05:11.230
and then in fits and starts,
00:05:11.230 --> 00:05:14.860
I work while giving my mind permission
00:05:14.860 --> 00:05:19.800
to wander to things that
absolutely are not on the agenda.
00:05:19.800 --> 00:05:24.200
It's encouraged some of my
most creative experiences,
00:05:24.200 --> 00:05:27.180
some of my best songwriting,
educational videos,
00:05:27.180 --> 00:05:29.580
and even scientific breakthroughs
while I was supposed
00:05:29.580 --> 00:05:32.300
to be working on something
totally unrelated.
00:05:32.300 --> 00:05:34.280
And this won't work for everyone,
00:05:34.280 --> 00:05:35.960
but my mind is most creative
00:05:35.960 --> 00:05:38.603
when it's free to go on
unplanned adventures.
00:05:39.490 --> 00:05:41.210
Good music also helps.
00:05:41.210 --> 00:05:44.980
A great playlist, to me, is
worth its weight and gold.
00:05:44.980 --> 00:05:46.610
My playlists are special
00:05:46.610 --> 00:05:49.638
because they only include
instrumental music
00:05:49.638 --> 00:05:53.300
and songs in languages that
I don't actually speak.
00:05:53.300 --> 00:05:54.840
So my thoughts don't get too pulled
00:05:54.840 --> 00:05:56.293
into the lyrics themselves.
00:06:03.620 --> 00:06:06.760
- I've used creative communication
to solve problems related
00:06:06.760 --> 00:06:10.150
to especially people
learning different science.
00:06:10.150 --> 00:06:13.720
For example, in chemistry,
people sometimes have a hard time
00:06:13.720 --> 00:06:18.480
understanding subatomic
particles and molecules and atoms
00:06:18.480 --> 00:06:22.210
and making those connections
between quantities and numbers.
00:06:22.210 --> 00:06:23.990
So instead of jumping right into that,
00:06:23.990 --> 00:06:25.710
which can be very difficult for people,
00:06:25.710 --> 00:06:28.010
I've learned to be
creative and use analogies
00:06:28.010 --> 00:06:30.040
or relating that to something
that is more accessible,
00:06:30.040 --> 00:06:34.240
such as cooking or money
or building something.
00:06:34.240 --> 00:06:36.080
And then when people
can make their relation
00:06:36.080 --> 00:06:38.540
between something large and familiar
00:06:38.540 --> 00:06:41.960
to something small or
subatomic and unfamiliar,
00:06:41.960 --> 00:06:44.860
it makes it easier for them
to make those connections
00:06:44.860 --> 00:06:46.520
and build upon that knowledge.
00:06:46.520 --> 00:06:49.070
- So, several years ago,
I started making videos
00:06:49.070 --> 00:06:52.690
of myself explaining biology
and entomology in language
00:06:52.690 --> 00:06:55.690
that was accessible and
familiar to people my age
00:06:55.690 --> 00:06:58.490
and people who don't fit
the stereotypical model
00:06:58.490 --> 00:06:59.850
of a scientist.
00:06:59.850 --> 00:07:02.560
It's a choice that I'm really
glad that I made actually.
00:07:02.560 --> 00:07:06.040
I've received so much
positive feedback about videos
00:07:06.040 --> 00:07:08.440
no more complicated than me holding a bug
00:07:08.440 --> 00:07:13.290
in front of a camera, and
actually, just like this.
00:07:13.290 --> 00:07:17.930
Me literally holding a
bug in front of a camera
00:07:17.930 --> 00:07:20.123
and explaining what makes it tick.
00:07:21.010 --> 00:07:23.840
Note to self, I should make a video
00:07:23.840 --> 00:07:26.420
about what makes ticks tick.
00:07:26.420 --> 00:07:27.253
That'd be pretty cool.
00:07:27.253 --> 00:07:28.960
Wait, sorry. That's
neither here nor there.
00:07:28.960 --> 00:07:32.120
The point of what I'm saying is the choice
00:07:32.120 --> 00:07:34.190
not to excise my personality,
00:07:34.190 --> 00:07:36.530
the choice to bring all of my quirkiness
00:07:36.530 --> 00:07:40.070
into how I communicate is what
seems to make the difference.
00:07:40.070 --> 00:07:41.640
A big part of being creative
00:07:41.640 --> 00:07:44.010
really can be just figuring out
00:07:44.010 --> 00:07:45.740
how to bring all of you
00:07:45.740 --> 00:07:47.740
to whatever it is that you choose to do.
00:07:52.130 --> 00:07:55.290
- I think biology is so critical
00:07:55.290 --> 00:07:58.010
for everybody to learn
00:07:58.010 --> 00:08:03.010
because it defines who we are
as human beings, as animals.
00:08:04.750 --> 00:08:07.670
It defines the whole animal kingdom.
00:08:07.670 --> 00:08:10.820
And then it goes on to define
the whole plant kingdom,
00:08:10.820 --> 00:08:12.770
the insect kingdom.
00:08:12.770 --> 00:08:17.770
Understanding those principles
of how living things
00:08:19.300 --> 00:08:24.300
are organized is not only a
beautiful thing to understand,
00:08:24.340 --> 00:08:28.810
but it gives deep insight
and deep appreciation
00:08:28.810 --> 00:08:31.150
for our own lives.
00:08:31.150 --> 00:08:36.150
And I think that is the core
of why I find it so important
00:08:36.970 --> 00:08:41.970
that everybody study this
beautiful area of academia.
00:08:43.200 --> 00:08:46.930
- Biology is super important
to learn for so many reasons.
00:08:46.930 --> 00:08:49.653
But the reason that stands
out most to me is, well,
00:08:51.750 --> 00:08:54.580
the rarity of life outside
of our little corner
00:08:54.580 --> 00:08:55.890
of the universe.
00:08:55.890 --> 00:08:59.900
You might not know what I mean,
but stick with me for a sec.
00:08:59.900 --> 00:09:04.080
So we are positively surrounded by biology
00:09:04.080 --> 00:09:05.810
every day here on Earth,
00:09:05.810 --> 00:09:07.490
but we haven't encountered life,
00:09:07.490 --> 00:09:10.910
or even evidence of life outside
of this little blue marvel,
00:09:10.910 --> 00:09:14.950
even though there is so much
cosmic real estate out there.
00:09:14.950 --> 00:09:17.340
Life is really complicated.
00:09:17.340 --> 00:09:20.650
And that goes for starting
and sustaining life.
00:09:20.650 --> 00:09:22.940
Somehow, ancient organisms
made it work here,
00:09:22.940 --> 00:09:24.760
but that doesn't mean that it's easy.
00:09:24.760 --> 00:09:28.260
All of us carry on this
legacy of life, finding a way.
00:09:28.260 --> 00:09:32.700
But one day, maybe life will
have to find a way through us.
00:09:32.700 --> 00:09:35.590
Maybe Earth becomes
inhospitable for some reason,
00:09:35.590 --> 00:09:38.840
and we have to figure out
how to live somewhere else.
00:09:38.840 --> 00:09:42.340
On that day, success
will depend on how well
00:09:42.340 --> 00:09:45.020
we understand the heaps of obstacles
00:09:45.020 --> 00:09:48.403
that the stubbornness of
life has already overcome.
|
The future of creativity in biology | https://www.youtube.com/watch?v=rBHbaYkn-rQ | vtt | https://www.youtube.com/api/timedtext?v=rBHbaYkn-rQ&ei=uVWUZYeJGbitp-oP0MWWoAc&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245289&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=0C6073CCDC938F3EB82F1CFD9AEBA360F7C8E164.03D6B7B3D6F347401A44E2795951FB3AA4AD2231&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.380 --> 00:00:03.047
(upbeat music)
00:00:11.900 --> 00:00:13.850
- Hi everyone, Sal Khan here.
00:00:13.850 --> 00:00:16.330
I think we're about to enter
what will be considered
00:00:16.330 --> 00:00:18.170
the golden age of biology,
00:00:18.170 --> 00:00:21.110
where not only do we understand
or are starting understand
00:00:21.110 --> 00:00:22.830
the genetic basis of things,
00:00:22.830 --> 00:00:25.310
but we also have the power to control it.
00:00:25.310 --> 00:00:26.640
And if you're controlling it
00:00:26.640 --> 00:00:29.480
then the creativity gets
to a whole other level.
00:00:29.480 --> 00:00:33.360
So in the decades to come,
creativity and biology,
00:00:33.360 --> 00:00:35.060
and also other areas of STEM,
00:00:35.060 --> 00:00:38.390
like mathematics and
computing are all going to
00:00:38.390 --> 00:00:42.540
converge to really transform
humanity as we know it.
00:00:42.540 --> 00:00:43.890
But don't take my word for it,
00:00:43.890 --> 00:00:46.670
I'm about to introduce
you to some close friends
00:00:46.670 --> 00:00:48.630
who can even better draw this link
00:00:48.630 --> 00:00:52.207
between the future of biology
and the future of creativity.
00:00:52.207 --> 00:00:54.874
(upbeat music)
00:00:58.610 --> 00:00:59.970
- I think it's really exciting
00:00:59.970 --> 00:01:03.560
how biology and creativity have combined,
00:01:03.560 --> 00:01:08.560
particularly in the area
of health and outcomes
00:01:08.650 --> 00:01:12.070
and how do we help people with blindness?
00:01:12.070 --> 00:01:15.380
How do we help people who are paraplegic
00:01:15.380 --> 00:01:19.130
where we can start to read
the electrical activity
00:01:19.130 --> 00:01:22.790
of their intended movement
and have a robot do that.
00:01:22.790 --> 00:01:27.790
So they can gain, you
know, that activity again
00:01:27.850 --> 00:01:31.210
and have that power in their lives again.
00:01:31.210 --> 00:01:35.300
I think that is a classic
and beautiful example
00:01:35.300 --> 00:01:39.630
of the combination of
biology and creativity
00:01:39.630 --> 00:01:42.710
making our lives better every single day
00:01:42.710 --> 00:01:45.790
- Butterflies use something
called structural color
00:01:45.790 --> 00:01:48.390
which involves bending
light to generate color
00:01:48.390 --> 00:01:50.530
instead of using a bunch of pigment.
00:01:50.530 --> 00:01:53.090
So it definitely saves the
butterflies a bunch of energy
00:01:53.090 --> 00:01:54.450
in making that pigment.
00:01:54.450 --> 00:01:56.720
But now, because of some observant
00:01:56.720 --> 00:01:59.930
and innovative scientists,
it's saving us energy too.
00:01:59.930 --> 00:02:02.770
It's being used in
screens around the world
00:02:02.770 --> 00:02:05.210
to make them more efficient
at projecting color,
00:02:05.210 --> 00:02:07.140
which reduces the carbon footprint
00:02:07.140 --> 00:02:09.720
as some of our most common electronics.
00:02:09.720 --> 00:02:12.770
And how about the
creativity of using mRNA,
00:02:12.770 --> 00:02:16.150
which is pretty much just
biological text messages
00:02:16.150 --> 00:02:18.500
to give our bodies a heads up
00:02:18.500 --> 00:02:20.940
that they need to recognize
dangerous viruses.
00:02:20.940 --> 00:02:23.040
It's the technology being used
00:02:23.040 --> 00:02:26.851
in some of our most
innovative vaccines right now.
00:02:26.851 --> 00:02:29.518
(upbeat music)
00:02:32.607 --> 00:02:35.430
- I think it's going to
be even more important
00:02:35.430 --> 00:02:40.430
to have the widest range of
skill sets that you could have.
00:02:40.890 --> 00:02:45.890
So less specialization,
more a jack of all trades,
00:02:48.840 --> 00:02:53.840
including design, design
thinking, design work,
00:02:54.690 --> 00:02:57.623
together with that programming experience.
00:02:59.330 --> 00:03:04.330
So that you can jump into the
new technological advances
00:03:04.330 --> 00:03:06.270
that are being made every day.
00:03:06.270 --> 00:03:10.290
We're gonna be so much
more in virtual reality,
00:03:10.290 --> 00:03:13.760
can you not just use it,
but can you program it?
00:03:13.760 --> 00:03:17.470
- I think the most important
ones will be curiosity
00:03:17.470 --> 00:03:20.230
and keen eyed to observational skills.
00:03:20.230 --> 00:03:23.300
See, curiosity fuels the question why
00:03:23.300 --> 00:03:26.150
which is an essential
part of every innovation,
00:03:26.150 --> 00:03:28.860
and keen observational skills allow us
00:03:28.860 --> 00:03:31.660
not to waste our efforts
reinventing the wheel.
00:03:31.660 --> 00:03:35.530
Life has already solved so
many of the toughest problems
00:03:35.530 --> 00:03:37.620
that the world can possibly throw at it.
00:03:37.620 --> 00:03:40.990
So why not figure out how
biology has overcome an obstacle
00:03:40.990 --> 00:03:42.543
and adapt or improve on that?
00:03:42.543 --> 00:03:45.210
(upbeat music)
00:03:48.800 --> 00:03:51.950
I'd encourage every single
one of you to spend some time
00:03:51.950 --> 00:03:53.660
immersed in a different culture
00:03:53.660 --> 00:03:56.350
or maybe even spend some time working
00:03:56.350 --> 00:03:58.160
in a totally different part of the world
00:03:58.160 --> 00:03:59.360
from where you grew up.
00:03:59.360 --> 00:04:03.320
Now, it doesn't have to
be quite that drastic.
00:04:03.320 --> 00:04:08.090
It could be as simple as
investing in relationships
00:04:08.090 --> 00:04:10.040
with people from other parts of the world.
00:04:10.040 --> 00:04:11.290
And while you're at it,
00:04:11.290 --> 00:04:13.570
I'd encourage you to learn
a different language.
00:04:13.570 --> 00:04:17.070
Both of those experiences, I think,
00:04:17.070 --> 00:04:18.770
will stretch your mind in ways
00:04:18.770 --> 00:04:22.180
that help you consider
other possibilities.
00:04:22.180 --> 00:04:24.520
- Students can expand their creative
00:04:24.520 --> 00:04:26.300
and scientific skill sets
00:04:26.300 --> 00:04:29.300
by thinking beyond the classroom
and beyond the textbook,
00:04:29.300 --> 00:04:32.250
using that information from
classroom and from the textbook
00:04:32.250 --> 00:04:34.790
and from other formal information sources
00:04:34.790 --> 00:04:38.400
and expanding that to learn
more about both today's world
00:04:38.400 --> 00:04:40.880
and the world that you
imagine for the future.
00:04:40.880 --> 00:04:43.660
That involves using those
skills such as communication
00:04:43.660 --> 00:04:46.040
and problem solving and critical thinking
00:04:46.040 --> 00:04:48.800
to wonder not just about
what is already known,
00:04:48.800 --> 00:04:51.090
but to wonder about what is not yet known,
00:04:51.090 --> 00:04:56.090
which involves using creativity
to think and to wonder.
00:04:56.800 --> 00:04:58.960
And that also means
communicating with other people
00:04:58.960 --> 00:05:01.289
to see how they wanna
shape the world as well.
00:05:01.289 --> 00:05:03.956
(upbeat music)
00:05:06.830 --> 00:05:09.290
- We have the opportunity to work together
00:05:09.290 --> 00:05:12.003
with a variety of different voices,
00:05:12.940 --> 00:05:14.910
colleagues from all over the world
00:05:14.910 --> 00:05:19.630
who have different
strengths that they bring,
00:05:19.630 --> 00:05:22.240
different perspectives
that they bring about life
00:05:22.240 --> 00:05:24.330
and about how the world operates.
00:05:24.330 --> 00:05:26.640
And only when we bring
those voices together,
00:05:26.640 --> 00:05:29.080
will we have a more complete picture
00:05:29.080 --> 00:05:31.520
about how the living world works.
00:05:31.520 --> 00:05:36.520
So in order to really solve
the problems of the future,
00:05:37.150 --> 00:05:40.120
we're going to need to work
together as a global community
00:05:40.120 --> 00:05:42.260
- Problems are not solved in isolation,
00:05:42.260 --> 00:05:45.380
they're solved in collaborative
groups with other people
00:05:45.380 --> 00:05:47.850
and they're solved to be realistic.
00:05:47.850 --> 00:05:50.300
So you have to consider not
just your own discipline
00:05:50.300 --> 00:05:54.240
or your own science, but also
some economics and ethics
00:05:54.240 --> 00:05:56.280
and other things that
relate to the real world,
00:05:56.280 --> 00:05:59.410
to help you reach a real
world, but sensible solution.
00:05:59.410 --> 00:06:00.740
So it requires combining
00:06:00.740 --> 00:06:02.660
all those different ways of thinking,
00:06:02.660 --> 00:06:05.110
being communicative and problem solving
00:06:05.110 --> 00:06:06.460
and working with other people
00:06:06.460 --> 00:06:08.140
so that you can reach solutions
00:06:08.140 --> 00:06:09.470
that actually benefit the world.
00:06:09.470 --> 00:06:12.560
Because some solutions are
gonna be great on paper,
00:06:12.560 --> 00:06:15.380
but in practice, they
aren't really practical.
00:06:15.380 --> 00:06:19.290
So that's why using new ways
of thinking to solve problems
00:06:19.290 --> 00:06:20.580
is really important.
00:06:20.580 --> 00:06:23.733
- As an example, for
me, in my PhD project,
00:06:25.320 --> 00:06:27.350
even though my background
has been in biology,
00:06:27.350 --> 00:06:32.140
the problem that really
captured my interests
00:06:32.140 --> 00:06:37.140
and that I wanted to pursue
involves mechanics and physics.
00:06:37.580 --> 00:06:42.160
And so it required learning
a lot of some deep theories
00:06:43.200 --> 00:06:46.200
and ideas in physics that I
wouldn't have thought of before.
00:06:46.200 --> 00:06:48.090
And now I kind approach,
00:06:48.090 --> 00:06:49.870
it sort of changed the way that I approach
00:06:49.870 --> 00:06:51.470
biological problems.
00:06:51.470 --> 00:06:54.710
Now I have this physics lens
that I didn't have before,
00:06:54.710 --> 00:06:59.700
and that expands the of
experiments I can think of
00:06:59.700 --> 00:07:02.308
or hypotheses that I could
have for how something works.
00:07:02.308 --> 00:07:04.975
(upbeat music)
00:07:08.990 --> 00:07:13.890
- What are those biological solutions
00:07:13.890 --> 00:07:16.710
that can be solved with creativity
00:07:16.710 --> 00:07:18.640
that would change the world?
00:07:18.640 --> 00:07:23.640
And I always go to those
health, biological changes.
00:07:25.670 --> 00:07:30.670
The cure for cancer,
the cure for blindness,
00:07:30.700 --> 00:07:35.700
the cure for name, Alzheimer's
disease, for example.
00:07:36.130 --> 00:07:40.950
The modulation of our crops
00:07:40.950 --> 00:07:44.720
that would allow us to
feed the world, everybody,
00:07:44.720 --> 00:07:46.500
so there's no starvation.
00:07:46.500 --> 00:07:51.410
That is the goal that
all of our creativity,
00:07:51.410 --> 00:07:55.410
kind of taken together, is headed towards.
00:07:55.410 --> 00:07:59.460
I think that's inspiring,
I think that is doable,
00:07:59.460 --> 00:08:02.730
and with all the tools that
we've been talking about,
00:08:02.730 --> 00:08:06.853
technology, storytelling, and inspiration,
00:08:08.690 --> 00:08:11.450
all of that together is
going to get us there.
00:08:11.450 --> 00:08:13.200
- A creative approach to biology
00:08:13.200 --> 00:08:16.440
can help solve the problems of the future.
00:08:16.440 --> 00:08:20.940
I mean, if you think
about natural systems,
00:08:20.940 --> 00:08:24.750
they don't have any waste,
they recycle everything.
00:08:24.750 --> 00:08:26.820
Everything that goes into a natural system
00:08:26.820 --> 00:08:28.740
is used completely.
00:08:28.740 --> 00:08:32.650
And there are a lot of areas
in which we can learn from that
00:08:32.650 --> 00:08:36.500
as people and the systems
that we create and design.
00:08:36.500 --> 00:08:40.710
So if we can design ways to
more efficiently use water,
00:08:40.710 --> 00:08:44.180
recycle and reduce the
amount of waste we produce,
00:08:44.180 --> 00:08:47.708
that's gonna be one of the
most important innovations
00:08:47.708 --> 00:08:49.080
of the future, right?
00:08:49.080 --> 00:08:52.570
Providing fresh and clean water
00:08:52.570 --> 00:08:55.040
to a growing population for this world.
00:08:55.040 --> 00:08:57.990
- New innovations that I
think will help us approach
00:08:57.990 --> 00:09:00.170
science creatively in the future,
00:09:00.170 --> 00:09:03.860
really involve data
such as machine learning
00:09:03.860 --> 00:09:05.440
and artificial intelligence,
00:09:05.440 --> 00:09:09.530
and using data to help humans
make decisions collaboratively
00:09:09.530 --> 00:09:10.590
with either other humans,
00:09:10.590 --> 00:09:13.080
but also with artificial intelligence.
00:09:13.080 --> 00:09:15.470
There's so much data
that exists in the world,
00:09:15.470 --> 00:09:18.520
collected from scientific
and engineering observations,
00:09:18.520 --> 00:09:21.146
that we can take this information
00:09:21.146 --> 00:09:23.910
to help us make better
decisions in the future.
00:09:23.910 --> 00:09:26.190
Because it's gonna be a
combination of people thinking
00:09:26.190 --> 00:09:28.010
but also machines thinking,
00:09:28.010 --> 00:09:30.923
and that can help us make
more powerful conclusions.
|
Creativity break: why is learning biology important? | https://www.youtube.com/watch?v=EHVC2ktR7ng | vtt | https://www.youtube.com/api/timedtext?v=EHVC2ktR7ng&ei=uVWUZdCHFdmIp-oPvvyy4Ag&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245289&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=BF295D8AD85419CDCF5A75E68409909FB29B60F8.5E2EED64970C94179AD30A98F43BDC23EA11817B&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
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(pencil scribbling)
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(gentle upbeat music)
00:00:09.900 --> 00:00:14.900
- I think biology is so
critical for everybody to learn
00:00:15.349 --> 00:00:20.349
because it defines who we are
as human beings, as animals.
00:00:22.550 --> 00:00:25.450
It defines the whole animal kingdom,
00:00:25.450 --> 00:00:28.271
and then it goes on to define
the whole plant kingdom,
00:00:28.271 --> 00:00:30.570
the insect kingdom.
00:00:30.570 --> 00:00:33.490
Understanding those principles
00:00:33.490 --> 00:00:38.490
of how living things are organized
00:00:38.590 --> 00:00:42.130
is not only a beautiful
thing to understand,
00:00:42.130 --> 00:00:45.845
but it gives deep insight
and deep appreciation
00:00:45.845 --> 00:00:48.950
for our own lives,
00:00:48.950 --> 00:00:53.950
and I think that is the core
of why I find it so important
00:00:54.780 --> 00:00:59.780
that everybody study this
beautiful area of academia.
00:01:01.000 --> 00:01:04.730
- Biology is super important
to learn for so many reasons.
00:01:04.730 --> 00:01:07.463
But the reason that stands
out most to me is, well,
00:01:08.805 --> 00:01:11.520
the rarity of life outside
00:01:11.520 --> 00:01:13.690
of our little corner of the universe.
00:01:13.690 --> 00:01:15.650
You might not know what I mean,
00:01:15.650 --> 00:01:17.315
but stick with me for a sec.
00:01:17.315 --> 00:01:20.690
So we are positively surrounded
00:01:20.690 --> 00:01:23.620
by biology every day here on Earth,
00:01:23.620 --> 00:01:26.300
but we haven't encountered
life or even evidence
00:01:26.300 --> 00:01:28.700
of life outside of this
little blue marvel,
00:01:28.700 --> 00:01:32.750
even though there is so much
cosmic real estate out there.
00:01:32.750 --> 00:01:35.140
Life is really complicated,
00:01:35.140 --> 00:01:38.440
and that goes for starting
and sustaining life.
00:01:38.440 --> 00:01:40.740
Somehow ancient organisms
made it work here,
00:01:40.740 --> 00:01:42.560
but that doesn't mean that it's easy.
00:01:42.560 --> 00:01:46.070
All of us carry on this
legacy of life finding a way,
00:01:46.070 --> 00:01:50.500
but one day maybe life will
have to find a way through us.
00:01:50.500 --> 00:01:53.490
Maybe Earth becomes
inhospitable for some reason
00:01:53.490 --> 00:01:56.630
and we have to figure out
how to live somewhere else.
00:01:56.630 --> 00:01:59.130
On that day, success will depend
00:01:59.130 --> 00:02:01.810
on how well we understand the heaps
00:02:01.810 --> 00:02:03.670
of obstacles that the stubbornness
00:02:03.670 --> 00:02:06.163
of life has already overcome.
|
Creativity break: why is creativity important in biology? | https://www.youtube.com/watch?v=RFezo2PlY3c | vtt | https://www.youtube.com/api/timedtext?v=RFezo2PlY3c&ei=uVWUZdyzA4iCp-oPgp6riAg&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245289&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=42ED32913677C4A4CC273FE6570DC34E7DD5E503.E75330E4CD6BD425A37794C4B3C87F882DC58367&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
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(upbeat music)
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(keyboard clicking)
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- Creativity is super important in biology
00:00:11.990 --> 00:00:14.980
because it's hugely important
in the process of evolution.
00:00:14.980 --> 00:00:17.550
Evolution often takes a winding path
00:00:17.550 --> 00:00:18.971
to get to what we see now,
00:00:18.971 --> 00:00:21.770
and we wanna follow this path
00:00:21.770 --> 00:00:23.850
in an attempt to understand it.
00:00:23.850 --> 00:00:26.590
Sometimes we've gotta be
as resourceful and clever
00:00:26.590 --> 00:00:27.960
as evolution has been.
00:00:27.960 --> 00:00:30.816
That requires creativity
in how we solve problems,
00:00:30.816 --> 00:00:34.400
and even creativity in
the questions we ask.
00:00:34.400 --> 00:00:37.834
- Creativity is so important for anybody
00:00:37.834 --> 00:00:41.380
who is thinking about,
who is studying biology,
00:00:41.380 --> 00:00:43.800
because the question
we're trying to understand
00:00:43.800 --> 00:00:46.330
is not just take in all the information
00:00:46.330 --> 00:00:48.610
that we know about biology.
00:00:48.610 --> 00:00:52.070
We want people to imagine what biology,
00:00:52.070 --> 00:00:55.110
what the natural world,
what the physical world,
00:00:55.110 --> 00:01:00.110
what our bodies can actually
do, what our brains can do.
00:01:00.600 --> 00:01:03.987
And to be able to do that, you
need to think out of the box.
00:01:03.987 --> 00:01:05.690
You need to think about things
00:01:05.690 --> 00:01:07.670
that haven't been thought about before.
00:01:07.670 --> 00:01:11.540
And that is why biology,
that is why creativity
00:01:11.540 --> 00:01:15.013
is so critical for
anybody studying biology.
|
Creativity break: how do you apply creativity to biology? | https://www.youtube.com/watch?v=VDRc0vkkLNU | vtt | https://www.youtube.com/api/timedtext?v=VDRc0vkkLNU&ei=uVWUZb_gGbitp-oP0MWWoAc&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245289&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=2EC62999622054E168184375F36C4B60784EAF6A.7F9277C96C6BF38E7C09CDC4C1ACC2B09A1AB53D&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
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(upbeat music)
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- One question that people ask me
00:00:12.160 --> 00:00:14.794
is how do I apply creativity
00:00:14.794 --> 00:00:18.090
to the presentations that I give?
00:00:18.090 --> 00:00:23.090
And my secret sauce is to
come up with a visual image
00:00:24.670 --> 00:00:26.930
that anybody, I don't
care if you're the adult,
00:00:26.930 --> 00:00:28.840
whether you're a fifth
grader or second grader,
00:00:28.840 --> 00:00:32.780
that you can grasp that concept,
and here's my favorite one.
00:00:32.780 --> 00:00:35.420
So every single time you move your body,
00:00:35.420 --> 00:00:37.510
there's whole bunches of neurochemicals
00:00:37.510 --> 00:00:40.150
that are released in your brain.
00:00:40.150 --> 00:00:41.970
And you've heard of these neurochemicals,
00:00:41.970 --> 00:00:44.960
dopamine, noradrenaline, serotonin.
00:00:44.960 --> 00:00:48.460
And so that's the fact,
but the image that I give
00:00:48.460 --> 00:00:50.980
is that every single
time you move your body,
00:00:50.980 --> 00:00:53.770
it's like giving your brain
a wonderful bubble bath
00:00:53.770 --> 00:00:56.540
of neurochemicals that enrich your brain
00:00:56.540 --> 00:01:00.140
that change that neurochemical milieu,
00:01:00.140 --> 00:01:01.960
and that is the image that everybody
00:01:01.960 --> 00:01:04.460
that comes to my talks leaves with
00:01:04.460 --> 00:01:07.410
and inspires them a little
bit to move their body more.
00:01:07.410 --> 00:01:09.610
So can you come up with that image,
00:01:09.610 --> 00:01:14.610
that playful fun, but
factually accurate image
00:01:15.280 --> 00:01:17.040
that conveys your message?
00:01:17.040 --> 00:01:19.290
That will be your secret sauce too.
00:01:19.290 --> 00:01:23.550
- Have you heard that the
bees aren't doing great?
00:01:23.550 --> 00:01:26.710
Well, I've been studying
that and trying to understand
00:01:26.710 --> 00:01:28.970
how their complex health issues
00:01:28.970 --> 00:01:31.140
connect to a curious little parasite
00:01:31.140 --> 00:01:34.940
that's in nearly every
honeybee colony worldwide.
00:01:34.940 --> 00:01:38.350
it's called Varroa destructor, by the way.
00:01:38.350 --> 00:01:41.950
Now, before I started
this study, we thought
00:01:41.950 --> 00:01:44.010
that it was an open and shut case
00:01:44.010 --> 00:01:46.570
that the parasite was
sucking out the bee's blood,
00:01:46.570 --> 00:01:49.280
sort of like a tick on a puppy,
00:01:49.280 --> 00:01:53.050
but I thought something more
strange might be going on.
00:01:53.050 --> 00:01:55.700
The damage that it caused
just didn't seem like
00:01:55.700 --> 00:01:58.450
the damage that would be
caused by blood removal.
00:01:58.450 --> 00:02:01.430
The feeding process is super
difficult to see though,
00:02:01.430 --> 00:02:04.860
so I had this idea.
00:02:04.860 --> 00:02:07.700
I fed different color glowing food
00:02:07.700 --> 00:02:10.180
to the bees in their pollen
and their sugar water
00:02:10.180 --> 00:02:13.200
to color their organs specific colors.
00:02:13.200 --> 00:02:16.830
Then when the parasite fed on the bees,
00:02:16.830 --> 00:02:18.960
I could tell which organ it was eating
00:02:18.960 --> 00:02:22.200
based on which color was
in its digestive system.
00:02:22.200 --> 00:02:25.890
And it turns out they were
eating the bees' liver,
00:02:25.890 --> 00:02:29.460
by the way, which is pretty weird.
00:02:29.460 --> 00:02:32.330
But this kind of work
is actually pretty fun,
00:02:32.330 --> 00:02:34.830
and it was definitely a
place where creativity
00:02:34.830 --> 00:02:36.900
was rewarded in biology.
00:02:36.900 --> 00:02:39.567
(upbeat music)
|
Creativity break: what types of science jobs involve creativity? | https://www.youtube.com/watch?v=N34Vowgievg | vtt | https://www.youtube.com/api/timedtext?v=N34Vowgievg&ei=uVWUZb61GM-5vdIPn_y-4A0&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245289&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=03F2597DED035658ED5F4BF6EAC5695461E40E3B.9875D81FD07F3AEC5BD1B2035BFD1414E556F37D&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
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(upbeat music)
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- All science careers involve creativity.
00:00:13.750 --> 00:00:14.620
Think about it.
00:00:14.620 --> 00:00:17.010
We're asking and answering questions,
00:00:17.010 --> 00:00:19.690
and we're solving the world's problems.
00:00:19.690 --> 00:00:24.040
So the more creatively we can
solve the world's problems,
00:00:24.040 --> 00:00:26.800
the more new ideas and concepts
00:00:26.800 --> 00:00:30.420
and approaches we can use to
address the world's problems,
00:00:30.420 --> 00:00:31.600
the better off we'll be.
00:00:31.600 --> 00:00:33.550
- Creativity is the guiding force
00:00:33.550 --> 00:00:35.110
on the path to good science.
00:00:35.110 --> 00:00:37.570
So there isn't a science job out there
00:00:37.570 --> 00:00:40.090
that doesn't benefit from creativity.
00:00:40.090 --> 00:00:42.780
Like you can be an engineer,
00:00:42.780 --> 00:00:45.340
building more efficient
transistors for tinier
00:00:45.340 --> 00:00:46.660
and tinier phones.
00:00:46.660 --> 00:00:48.060
You could be a climate scientist,
00:00:48.060 --> 00:00:50.950
figuring out how we can
reduce our carbon footprint
00:00:50.950 --> 00:00:53.210
and save the world from
climate catastrophe,
00:00:53.210 --> 00:00:55.370
or an agricultural researcher.
00:00:55.370 --> 00:00:58.010
Reducing efficient ways
to feed the planet.
00:00:58.010 --> 00:01:00.550
Or maybe an entomologist like me.
00:01:00.550 --> 00:01:04.200
Understanding how
relationships between organisms
00:01:04.200 --> 00:01:05.470
keep us all healthy.
00:01:05.470 --> 00:01:08.700
Creativity is important
in all of these careers.
00:01:08.700 --> 00:01:09.950
- One really cool job is,
00:01:11.210 --> 00:01:13.740
is working for a science museum.
00:01:13.740 --> 00:01:16.080
And so the people who are like the
00:01:16.080 --> 00:01:18.622
the chief directors or bioscientist,
00:01:18.622 --> 00:01:21.930
or what have you for science
museums usually have a biology
00:01:21.930 --> 00:01:25.160
or a science background of some kind,
00:01:25.160 --> 00:01:28.080
maybe you've have gone
through even being a PhD
00:01:28.080 --> 00:01:29.833
or postdoctoral fellow.
00:01:31.967 --> 00:01:35.300
And their job is to design exhibits for,
00:01:35.300 --> 00:01:37.770
for visitors to museums
00:01:37.770 --> 00:01:42.770
and come up with engaging ways
to share ideas in science.
00:01:42.800 --> 00:01:45.540
And so I see that's a really cool job
00:01:47.230 --> 00:01:49.230
that you might not immediately think of.
00:01:50.655 --> 00:01:52.427
(upbeat music)
|
Creativity break: how is creativity in biology changing the world? | https://www.youtube.com/watch?v=w8wR836X1q4 | vtt | https://www.youtube.com/api/timedtext?v=w8wR836X1q4&ei=uVWUZbjzGK3mxN8Ppv2xgAg&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245289&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=572CC0B8A6BF61D746F7ADE72FF0B0E7C59DA898.2279D32734A4F2238127BEDFAFD6F0032D049CB8&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
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00:00:00.142 --> 00:00:02.725
(upbeat music)
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(logos pop)
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(screen whooshes)
00:00:06.315 --> 00:00:09.148
(keyboard clicks)
00:00:11.460 --> 00:00:12.820
- I think it's really exciting
00:00:12.820 --> 00:00:16.400
how biology and creativity have combined,
00:00:16.400 --> 00:00:21.400
particularly in the area
of health and outcomes.
00:00:21.490 --> 00:00:24.910
And how do we help people with blindness?
00:00:24.910 --> 00:00:28.210
How do we help people who are paraplegic,
00:00:28.210 --> 00:00:31.970
where we can start to read
the electrical activity
00:00:31.970 --> 00:00:35.624
of their intended movement
and have a robot do that.
00:00:35.624 --> 00:00:38.310
So they can gain, you know,
00:00:38.310 --> 00:00:40.700
that activity again,
00:00:40.700 --> 00:00:44.060
and have that power in their lives again.
00:00:44.060 --> 00:00:46.020
I think that is a classic
00:00:46.020 --> 00:00:49.460
and beautiful example of the combination
00:00:49.460 --> 00:00:54.460
of biology and creativity
making our lives better
00:00:54.500 --> 00:00:55.550
every single day
00:00:55.550 --> 00:00:58.640
- Butterflies use something
called structural color
00:00:58.640 --> 00:01:01.850
which involves bending light
to generate color instead
00:01:01.850 --> 00:01:03.370
of using a bunch of pigment.
00:01:03.370 --> 00:01:05.120
So it definitely saves the butterflies
00:01:05.120 --> 00:01:07.280
a bunch of energy in making that pigment.
00:01:07.280 --> 00:01:10.980
But now because of some observant
and innovative scientists
00:01:10.980 --> 00:01:12.770
it's saving us energy too.
00:01:12.770 --> 00:01:14.520
It's being used in screens
00:01:14.520 --> 00:01:16.850
around the world to
make them more efficient
00:01:16.850 --> 00:01:19.970
at projecting color, which
reduces the carbon footprint
00:01:19.970 --> 00:01:22.570
as some of our most common electronics.
00:01:22.570 --> 00:01:25.620
And how about the creativity of using mRNA
00:01:25.620 --> 00:01:29.000
which is pretty much just
biological text messages
00:01:29.000 --> 00:01:31.350
to give our bodies a heads up
00:01:31.350 --> 00:01:33.790
that they need to recognize
dangerous viruses.
00:01:33.790 --> 00:01:36.540
It's the technology being used in some
00:01:36.540 --> 00:01:39.548
of our most innovative vaccines right now.
00:01:39.548 --> 00:01:40.748
(screen whooshes)
00:01:40.748 --> 00:01:43.232
(upbeat music)
|
Creativity break: what types of skills will help students innovate in biology? | https://www.youtube.com/watch?v=rF7yuIYELNU | vtt | https://www.youtube.com/api/timedtext?v=rF7yuIYELNU&ei=uVWUZY6EG7q4mLAPob-_oAU&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245289&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=3ADDB2BB8FB711AF6045FF379A44D657C1245F52.790E3BE97264EAD4874B10879EB4429C55742A41&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
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(upbeat music)
00:00:11.270 --> 00:00:13.940
- I think it's going to
be even more important
00:00:13.940 --> 00:00:18.940
to have the widest range of
skillsets that you could have,
00:00:19.410 --> 00:00:24.410
so less specialization,
more a jack-of-all-trades,
00:00:27.350 --> 00:00:32.350
including design, design
thinking, design work,
00:00:33.220 --> 00:00:36.133
together with that programming experience,
00:00:37.840 --> 00:00:42.840
so that you can jump into the
new technological advances
00:00:42.850 --> 00:00:44.790
that are being made every day.
00:00:44.790 --> 00:00:48.810
We're gonna be so much
more in virtual reality,
00:00:48.810 --> 00:00:52.280
can you not just use it,
but can you program it?
00:00:52.280 --> 00:00:55.990
- I think the most important
ones will be curiosity
00:00:55.990 --> 00:00:58.750
and keen-eyed observational skills.
00:00:58.750 --> 00:01:01.810
See, curiosity fuels the question why,
00:01:01.810 --> 00:01:04.660
which is an essential
part of every innovation,
00:01:04.660 --> 00:01:07.380
and keen observational skills allow us
00:01:07.380 --> 00:01:10.180
not to waste our effort
reinventing the wheel.
00:01:10.180 --> 00:01:14.070
Life has already solved so
many of the toughest problems
00:01:14.070 --> 00:01:16.140
that the world can possibly throw in it,
00:01:16.140 --> 00:01:19.500
so why not figure out how
biology has overcome an obstacle
00:01:19.500 --> 00:01:21.341
and adapt or improve on that?
00:01:21.341 --> 00:01:23.924
(upbeat music)
|
Creativity break: how can students expand their creativity in biology? | https://www.youtube.com/watch?v=B-up-XLGQIA | vtt | https://www.youtube.com/api/timedtext?v=B-up-XLGQIA&ei=uVWUZajSJeGJp-oP-P2AqAs&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245289&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=4A143F64AA54996DBECFC5576CF001CB324965AC.9690E1AD99592245A68BC430E9DD5C493414FE5F&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.311 --> 00:00:02.894
(bright music)
00:00:06.574 --> 00:00:09.657
(keyboard clacking)
00:00:11.310 --> 00:00:13.530
- I'd encourage every single one of you
00:00:13.530 --> 00:00:16.130
to spend some time immersed
in a different culture
00:00:16.130 --> 00:00:18.830
or maybe even spend some time working
00:00:18.830 --> 00:00:20.650
in a totally different part of the world
00:00:20.650 --> 00:00:22.271
from where you grew up.
00:00:22.271 --> 00:00:23.170
And...
00:00:23.170 --> 00:00:25.810
It doesn't have to be quite that drastic.
00:00:25.810 --> 00:00:30.590
It could be as simple as
investing in relationships
00:00:30.590 --> 00:00:32.520
with people from other parts of the world.
00:00:32.520 --> 00:00:33.780
And while you're at it,
00:00:33.780 --> 00:00:36.180
I'd encourage you to learn
a different language.
00:00:37.086 --> 00:00:39.550
Both of those experiences, I think,
00:00:39.550 --> 00:00:41.240
will stretch your mind in ways
00:00:41.240 --> 00:00:44.660
that help you consider
other possibilities.
00:00:44.660 --> 00:00:47.000
- Students can expand their creative
00:00:47.000 --> 00:00:48.780
and scientific skill sets
00:00:48.780 --> 00:00:51.780
by thinking beyond the classroom
and beyond the textbook,
00:00:51.780 --> 00:00:52.870
using that information
00:00:52.870 --> 00:00:54.730
from classroom and from the textbook
00:00:54.730 --> 00:00:57.260
and from other formal information sources,
00:00:57.260 --> 00:01:00.880
and expanding that to learn
more about both today's world
00:01:00.880 --> 00:01:03.360
and the world that you
imagine for the future.
00:01:03.360 --> 00:01:05.140
That involves using those skills
00:01:05.140 --> 00:01:07.000
such as communication,
and problem-solving,
00:01:07.000 --> 00:01:08.520
and critical thinking
00:01:08.520 --> 00:01:11.260
to wonder not just about
what is already known,
00:01:11.260 --> 00:01:13.560
but to wonder about what is not yet known,
00:01:13.560 --> 00:01:18.560
which involves using creativity
to think and to wonder.
00:01:19.270 --> 00:01:21.430
And that also means
communicating with other people
00:01:21.430 --> 00:01:23.637
to see how wanna shape the world as well.
00:01:23.637 --> 00:01:26.220
(bright music)
|
Creativity break: how does creativity play a role in your everyday life? | https://www.youtube.com/watch?v=urs0Pep2Wdc | vtt | https://www.youtube.com/api/timedtext?v=urs0Pep2Wdc&ei=uVWUZYysG6qWvdIPvZSk6As&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245289&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=C4D1F1DE688B818527EAD388544DEBE1A5AADE4E.BE262B59F215243A5654004989A8A5B19DF649F0&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.251 --> 00:00:02.751
(light music)
00:00:10.270 --> 00:00:13.946
- As we move forward, as
scientists, as biologists,
00:00:13.946 --> 00:00:17.067
the old adage is true:
00:00:17.067 --> 00:00:22.010
A picture is worth a thousand words.
00:00:22.010 --> 00:00:27.010
So what is that image,
that graph, that graphic,
00:00:27.510 --> 00:00:29.460
or even that imagery
00:00:30.454 --> 00:00:35.375
that really gets to the core of your idea.
00:00:35.375 --> 00:00:37.740
It almost gets to advertising.
00:00:37.740 --> 00:00:42.740
You want that image to stick
in your listeners' minds
00:00:42.925 --> 00:00:47.280
that both lets them understand
00:00:47.280 --> 00:00:51.360
the undeniably complex concept
that you're trying to convey
00:00:51.360 --> 00:00:53.654
but also makes it memorable
00:00:53.654 --> 00:00:58.430
and developing that skill
to come up with that picture
00:00:58.430 --> 00:01:01.293
that is truly worth a thousand words
00:01:01.293 --> 00:01:05.472
is going to be the skill
that we will all need
00:01:05.472 --> 00:01:07.030
going into the future.
00:01:07.030 --> 00:01:09.670
- Creativity plays a role in my life
00:01:09.670 --> 00:01:13.307
pretty much every single day
by reminding me not to stop
00:01:13.307 --> 00:01:15.350
just because I've reached a setback,
00:01:15.350 --> 00:01:18.720
like hitting a wall as
you're moving towards a goal
00:01:18.720 --> 00:01:20.926
doesn't have to be the end for that goal.
00:01:20.926 --> 00:01:23.609
To me it just means the path to success
00:01:23.609 --> 00:01:25.990
isn't gonna be quite as straightforward
00:01:25.990 --> 00:01:27.260
as I originally thought.
00:01:27.260 --> 00:01:29.180
Like the way around that wall
00:01:29.180 --> 00:01:32.550
may require me to climb
over it, or tunnel under it,
00:01:32.550 --> 00:01:35.180
or maybe even dig straight through it.
00:01:35.180 --> 00:01:36.732
But if I'm creative enough,
00:01:36.732 --> 00:01:39.959
I can probably find a way
to get to the other side.
00:01:39.959 --> 00:01:42.440
And this plays out for me in the lab
00:01:42.440 --> 00:01:44.710
literally every single day.
00:01:44.710 --> 00:01:47.737
It fuels a tenacity that
can see you through things
00:01:47.737 --> 00:01:50.637
like graduate school, if you
ever choose to go that route.
|
Creativity break: how do you get into your creative zone? | https://www.youtube.com/watch?v=SdzST7SD3ig | vtt | https://www.youtube.com/api/timedtext?v=SdzST7SD3ig&ei=uVWUZd-KGNfDmLAPiYWDsAk&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245289&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=ECB9A3770F28C327891BE63C7A406F158115BE10.48FC57D26BF112FC6E1C55CEBC9F702636F4DD31&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.060 --> 00:00:02.643
(upbeat music)
00:00:10.550 --> 00:00:12.510
- I allow my brain to do the work
00:00:12.510 --> 00:00:14.800
to get into my creative zone.
00:00:14.800 --> 00:00:16.964
When I have a problem to resolve,
00:00:16.964 --> 00:00:18.550
sometimes I just sleep on it
00:00:18.550 --> 00:00:22.160
and I let my subconscious mind work
00:00:22.160 --> 00:00:26.000
through resolving problems
and solving problems.
00:00:26.000 --> 00:00:28.310
Our brains are always at work
00:00:28.310 --> 00:00:32.950
like trying to defragment and break apart
00:00:32.950 --> 00:00:34.890
the things that we encounter.
00:00:34.890 --> 00:00:38.570
So I spend a little time thinking about
00:00:38.570 --> 00:00:41.340
how I can approach things creatively,
00:00:41.340 --> 00:00:43.270
and then I spend a little time
00:00:43.270 --> 00:00:45.070
not thinking about those things
00:00:45.070 --> 00:00:48.080
and allowing my brain
and my subconscious mind
00:00:48.080 --> 00:00:51.290
to have an opportunity
to do the work for me.
00:00:51.290 --> 00:00:53.820
A lot of times when I
come back afterwards,
00:00:53.820 --> 00:00:56.560
I've got a great idea,
I've got the answers,
00:00:56.560 --> 00:00:59.620
and I have new ways to
solve and resolve things
00:00:59.620 --> 00:01:01.320
that I've been thinking about.
00:01:01.320 --> 00:01:03.930
- To get into my creative
zone, I do something
00:01:03.930 --> 00:01:07.390
that I'd like to call
productive procrastination.
00:01:07.390 --> 00:01:10.630
I start what I'm working
on way before it's due,
00:01:10.630 --> 00:01:12.570
and then in fits and starts,
00:01:12.570 --> 00:01:17.520
I work while giving my mind
permission to wander to things
00:01:17.520 --> 00:01:21.070
that absolutely are not on the agenda.
00:01:21.070 --> 00:01:25.480
It's encouraged some of my
most creative experiences,
00:01:25.480 --> 00:01:28.470
some of my best songwriting,
educational videos,
00:01:28.470 --> 00:01:30.010
and even scientific breakthroughs
00:01:30.010 --> 00:01:31.460
while I was supposed to be working
00:01:31.460 --> 00:01:33.980
on something totally unrelated.
00:01:33.980 --> 00:01:35.570
This won't work for everyone,
00:01:35.570 --> 00:01:37.250
but my mind is most creative
00:01:37.250 --> 00:01:39.883
when it's free to go on
unplanned adventures.
00:01:40.770 --> 00:01:42.490
Good music also helps.
00:01:42.490 --> 00:01:46.260
A great playlist to me is
worth its weight in gold.
00:01:46.260 --> 00:01:47.890
My playlists are special,
00:01:47.890 --> 00:01:52.300
because they only include
instrumental music and songs
00:01:52.300 --> 00:01:54.600
in languages that I don't actually speak,
00:01:54.600 --> 00:01:56.120
so my thoughts don't get too pulled
00:01:56.120 --> 00:01:57.638
into the lyrics themselves.
00:01:57.638 --> 00:02:00.221
(upbeat music)
|
Creativity break: what are some new ways of thinking about problem solving? | https://www.youtube.com/watch?v=LOgjCaCn9_E | vtt | https://www.youtube.com/api/timedtext?v=LOgjCaCn9_E&ei=uVWUZe29GfvoxN8P4Oy1sAs&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245289&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=C6A066E25172ED62CE95F41E93B60E48472A0CF3.79745682B6E22B300115D633A6E4F65624320548&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.000 --> 00:00:02.583
(upbeat music)
00:00:11.350 --> 00:00:15.010
- We have the opportunity to
work together with a variety
00:00:15.010 --> 00:00:19.410
of different voices, colleagues
from all over the world
00:00:19.410 --> 00:00:24.140
who have different
strengths that they bring,
00:00:24.140 --> 00:00:25.940
different perspectives that they bring,
00:00:25.940 --> 00:00:28.870
about life, and about
how the world operates,
00:00:28.870 --> 00:00:31.160
and only when we bring
those voices together
00:00:31.160 --> 00:00:33.580
will we have a more complete picture
00:00:33.580 --> 00:00:36.040
about how the living world works.
00:00:36.040 --> 00:00:41.040
So in order to really solve
the problems of the future,
00:00:41.680 --> 00:00:43.030
we're going to need to work together
00:00:43.030 --> 00:00:44.630
as a global community.
00:00:44.630 --> 00:00:46.780
- Problems are not solved in isolation.
00:00:46.780 --> 00:00:49.900
They're solved in collaborative
groups with other people,
00:00:49.900 --> 00:00:52.360
and they're solved to be realistic.
00:00:52.360 --> 00:00:54.820
So you have to consider not
just your own discipline
00:00:54.820 --> 00:00:58.790
or your own science, but also
some economics, and ethics,
00:00:58.790 --> 00:01:00.800
and other things that
relate to the real world
00:01:00.800 --> 00:01:03.940
to help you reach a real
world, but sensible, solution.
00:01:03.940 --> 00:01:06.380
So it requires combining
all those different ways
00:01:06.380 --> 00:01:09.560
of thinking, being communicative
and problem solving
00:01:09.560 --> 00:01:10.990
and working with other people
00:01:10.990 --> 00:01:12.660
so that you can reach solutions
00:01:12.660 --> 00:01:13.990
that actually benefit the world,
00:01:13.990 --> 00:01:17.090
because some solutions are
gonna be great on paper,
00:01:17.090 --> 00:01:19.910
but in practice, they
aren't really practical.
00:01:19.910 --> 00:01:21.620
So that's why using new ways
00:01:21.620 --> 00:01:25.110
of thinking to solve
problems is really important.
00:01:25.110 --> 00:01:28.223
- As an example, for
me, in my PhD project,
00:01:29.860 --> 00:01:31.860
even though my background
has been in biology,
00:01:31.860 --> 00:01:36.670
the problem that really
captured my interest
00:01:36.670 --> 00:01:41.670
and that I wanted to pursue
involves mechanics and physics.
00:01:42.100 --> 00:01:44.420
And so it required learning a lot
00:01:44.420 --> 00:01:48.650
of some deep theories and ideas in physics
00:01:48.650 --> 00:01:50.700
that I wouldn't have thought of before,
00:01:50.700 --> 00:01:52.610
and now I kinda approach,
00:01:52.610 --> 00:01:53.710
it sort of changed the way
00:01:53.710 --> 00:01:56.000
that I approach biological problems.
00:01:56.000 --> 00:01:59.240
Now I have this physics lens
that I didn't have before,
00:01:59.240 --> 00:02:02.680
and that expands the possibilities
00:02:02.680 --> 00:02:04.220
of experiments I can think of,
00:02:04.220 --> 00:02:06.832
or hypotheses that I could
have for how something works.
00:02:06.832 --> 00:02:09.499
(upbeat music)
|
Creativity break: how have you used creative communication to solve a problem? | https://www.youtube.com/watch?v=DAKmXK-qWJ8 | vtt | https://www.youtube.com/api/timedtext?v=DAKmXK-qWJ8&ei=uVWUZYHtGvGqmLAPlcyDmAI&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245289&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=168C0BA290AD8217E724D577143BFF2040B99A09.4D8C2B24656829A250B7D3FD0DC85C6EA255172F&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.000 --> 00:00:02.667
(gentle music)
00:00:12.750 --> 00:00:15.880
- I've used creative communication
to solve problems related
00:00:15.880 --> 00:00:19.290
to especially people
learning different science.
00:00:19.290 --> 00:00:22.840
For example, in chemistry people
sometimes have a hard time
00:00:22.840 --> 00:00:25.450
understanding subatomic particles
00:00:25.450 --> 00:00:29.310
and molecules and atoms and
making those connections
00:00:29.310 --> 00:00:31.330
between quantities and numbers.
00:00:31.330 --> 00:00:33.120
So instead of jumping right into that
00:00:33.120 --> 00:00:34.840
which can be very difficult for people,
00:00:34.840 --> 00:00:37.130
I've learned to be
creative and use analogies
00:00:37.130 --> 00:00:39.160
or relating that to something
that is more accessible
00:00:39.160 --> 00:00:43.360
such as cooking or money
or building something.
00:00:43.360 --> 00:00:45.210
And then when people can make the relation
00:00:45.210 --> 00:00:47.650
between something large and familiar,
00:00:47.650 --> 00:00:51.070
to something small or
subatomic and unfamiliar
00:00:51.070 --> 00:00:53.980
it makes it easier for them
to make those connections
00:00:53.980 --> 00:00:55.650
and build upon that knowledge.
00:00:55.650 --> 00:00:58.760
So several years ago I started
making videos of myself
00:00:58.760 --> 00:01:01.810
explaining biology and
entomology in language
00:01:01.810 --> 00:01:04.800
that was accessible and
familiar to people my age
00:01:04.800 --> 00:01:07.610
and people who don't fit
the stereotypical model
00:01:07.610 --> 00:01:08.970
of a scientist.
00:01:08.970 --> 00:01:11.670
It's a choice that I'm really
glad that I made actually.
00:01:11.670 --> 00:01:15.140
I've received so much
positive feedback about videos
00:01:15.140 --> 00:01:16.670
no more complicated than me
00:01:16.670 --> 00:01:18.390
holding a bug in front of a camera.
00:01:18.390 --> 00:01:21.679
And actually just like this,
00:01:21.679 --> 00:01:26.679
me literally holding a
bug in front of a camera
00:01:27.040 --> 00:01:29.417
and explaining what makes a tick.
00:01:29.417 --> 00:01:31.893
Note to self,
00:01:31.893 --> 00:01:35.540
I should make a video about
what makes ticks tick.
00:01:35.540 --> 00:01:36.373
That'd be pretty cool.
00:01:36.373 --> 00:01:38.090
Wait, sorry, that's
neither here nor there.
00:01:38.090 --> 00:01:40.130
The point of what I'm saying is
00:01:40.130 --> 00:01:43.300
the choice not to excise my personality,
00:01:43.300 --> 00:01:45.640
the choice to bring all of my quirkiness
00:01:45.640 --> 00:01:49.190
into how I communicate is what
seems to make the difference.
00:01:49.190 --> 00:01:52.801
A big part of being creative
really can be just figuring out
00:01:52.801 --> 00:01:54.870
how to bring all of you
00:01:54.870 --> 00:01:56.923
to whatever it is that you choose to do.
00:01:56.923 --> 00:01:59.590
(gentle music)
|
Phishing attacks | https://www.youtube.com/watch?v=83VKm3aLq3I | vtt | https://www.youtube.com/api/timedtext?v=83VKm3aLq3I&ei=uVWUZaLZH_KhhcIP87yYkA0&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245289&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=9D08F2E8810E2A194282E746B8007C898C00E28C.5BB05EF6C8D30C1F1CA8D52E791B7C0DF8CDB26C&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.120 --> 00:00:02.300
- [Instructor] Let's say
you get an email like this,
00:00:02.300 --> 00:00:04.780
where it looks like it is from PayPal.
00:00:04.780 --> 00:00:06.920
It says "Response required" really big,
00:00:06.920 --> 00:00:08.350
so this is a little bit scary.
00:00:08.350 --> 00:00:10.687
And it says, "Dear," you,
00:00:10.687 --> 00:00:14.007
"We emailed you a little while
ago to ask you for your help
00:00:14.007 --> 00:00:16.820
"resolving an issue with
your PayPal account."
00:00:16.820 --> 00:00:18.417
This seems really serious.
00:00:18.417 --> 00:00:21.047
"Your account is still temporarily limited
00:00:21.047 --> 00:00:22.797
"because we haven't heard from you.
00:00:22.797 --> 00:00:27.467
"We noticed some unusual login
activity with your account.
00:00:27.467 --> 00:00:29.947
"Please check that no one
has logged into your account
00:00:29.947 --> 00:00:30.900
"without your permission."
00:00:30.900 --> 00:00:32.050
This is scary:
00:00:32.050 --> 00:00:33.110
To help us with this
00:00:33.110 --> 00:00:35.760
and to see what you can and
can't do with your account
00:00:35.760 --> 00:00:37.520
until the issue is resolved,
00:00:37.520 --> 00:00:41.620
log in to your account or
go to the Resolution Center.
00:00:41.620 --> 00:00:44.540
As always, if you need
help or have any questions,
00:00:44.540 --> 00:00:45.980
feel free to contact us.
00:00:45.980 --> 00:00:47.460
We're always here to help.
00:00:47.460 --> 00:00:49.930
Thank you for being a PayPal customer.
00:00:49.930 --> 00:00:51.750
Sincerely, PayPal.
00:00:51.750 --> 00:00:54.820
What would you do in this situation?
00:00:54.820 --> 00:00:57.120
Well, I think for a lot of
us, our emotional response is,
00:00:57.120 --> 00:01:00.290
hey, PayPal, some of my
money is involved, there.
00:01:00.290 --> 00:01:02.870
They're talking about other
people maybe trying to log in.
00:01:02.870 --> 00:01:04.400
I definitely wanna resolve this.
00:01:04.400 --> 00:01:06.150
And just in the heat of the moment,
00:01:06.150 --> 00:01:07.790
you might click on this "log in,"
00:01:07.790 --> 00:01:09.940
or you might go to the Resolution Center,
00:01:09.940 --> 00:01:14.460
and that might start you down
a little bit of a scary path.
00:01:14.460 --> 00:01:17.410
Because even though
this looks like PayPal,
00:01:17.410 --> 00:01:21.430
you really need to verify
that it really is PayPal.
00:01:21.430 --> 00:01:23.490
And there are some clues here
00:01:23.490 --> 00:01:26.060
that make it clear that it is not PayPal.
00:01:26.060 --> 00:01:27.583
See if you can find those.
00:01:29.850 --> 00:01:33.430
Well, the biggest clue is up
here on the email address.
00:01:33.430 --> 00:01:38.430
So, it says [email protected]
as its name,
00:01:38.770 --> 00:01:40.220
but when you look at the actual
00:01:40.220 --> 00:01:41.880
email address right over here,
00:01:41.880 --> 00:01:45.240
notice it actually isn't
a PayPal email address.
00:01:45.240 --> 00:01:48.570
It says @outlook.com.
00:01:48.570 --> 00:01:52.350
So, this is a pretty good clue
that this is not from PayPal.
00:01:52.350 --> 00:01:53.940
And so, what is this?
00:01:53.940 --> 00:01:58.090
Well, this is known as a phishing attack.
00:01:58.090 --> 00:02:00.400
Why is it called a phishing attack?
00:02:00.400 --> 00:02:03.270
Well, I think it's
probably based on the idea
00:02:03.270 --> 00:02:05.610
that when you're trying to catch fish,
00:02:05.610 --> 00:02:07.290
you dangle some bait for the fish
00:02:07.290 --> 00:02:09.680
and you see which fish are going to bite.
00:02:09.680 --> 00:02:11.300
And so, this isn't exactly fishing.
00:02:11.300 --> 00:02:14.030
They spelled the "Fuh" sound P-H
00:02:14.030 --> 00:02:15.330
because what they're really doing
00:02:15.330 --> 00:02:17.630
is they're dangling some
bait in front of you
00:02:17.630 --> 00:02:20.760
and see if you're going to metaphorically
00:02:20.760 --> 00:02:22.950
get your cheek cut by the fish hook
00:02:22.950 --> 00:02:25.780
or whatever happens to fish
before they get pulled out.
00:02:25.780 --> 00:02:28.010
And how would that happen metaphorically?
00:02:28.010 --> 00:02:29.680
Well, when you click on this,
00:02:29.680 --> 00:02:34.680
it probably goes to this phishy
company or person's website.
00:02:36.280 --> 00:02:39.180
And that website might look like PayPal,
00:02:39.180 --> 00:02:42.170
but it's not going to be paypal.com.
00:02:42.170 --> 00:02:44.800
It's going to be some other web address.
00:02:44.800 --> 00:02:47.730
And so, one way to avoid
doing that beyond looking
00:02:47.730 --> 00:02:50.510
at that this is a phishy email address
00:02:50.510 --> 00:02:53.532
is that in some browsers
or in some email readers,
00:02:53.532 --> 00:02:55.010
you can scroll over this
00:02:55.010 --> 00:02:57.280
and you'll see what the website would be.
00:02:57.280 --> 00:02:58.840
Or you can right click on that.
00:02:58.840 --> 00:03:01.000
You could, say, copy the URL
00:03:01.000 --> 00:03:02.590
and you could put that in a text document
00:03:02.590 --> 00:03:04.600
to see what the actual URL is.
00:03:04.600 --> 00:03:05.870
And it's very likely
00:03:05.870 --> 00:03:08.350
that that is not going to be a PayPal URL.
00:03:08.350 --> 00:03:10.040
In fact, I would
guarantee you in this case
00:03:10.040 --> 00:03:11.360
it would not be.
00:03:11.360 --> 00:03:13.110
It would look like PayPal
when you get there,
00:03:13.110 --> 00:03:15.400
and what they'll probably
try to get you to do
00:03:15.400 --> 00:03:17.990
is type in your username and password
00:03:17.990 --> 00:03:19.850
for your PayPal account.
00:03:19.850 --> 00:03:21.420
Why is that valuable for them?
00:03:21.420 --> 00:03:24.180
Well, you just would have
then given them your username
00:03:24.180 --> 00:03:26.610
and password for your PayPal account,
00:03:26.610 --> 00:03:29.950
which then they could use
to steal money from you
00:03:29.950 --> 00:03:32.600
or to do something else to you.
00:03:32.600 --> 00:03:33.940
So, be very careful
00:03:33.940 --> 00:03:36.990
where you get these
urgent emails or texts.
00:03:36.990 --> 00:03:38.857
I got a text recently saying that,
00:03:38.857 --> 00:03:41.457
"Your Amazon account has been compromised.
00:03:41.457 --> 00:03:43.747
"Click here fast in order to make sure
00:03:43.747 --> 00:03:45.820
"that no more fraud
happens on your account."
00:03:45.820 --> 00:03:47.870
Well, it turns out that the URL,
00:03:47.870 --> 00:03:51.310
the web address there was not amazon.com.
00:03:51.310 --> 00:03:53.210
It was going to take
me to a shady website,
00:03:53.210 --> 00:03:55.680
and that shady website
looked a lot like Amazon.
00:03:55.680 --> 00:03:56.890
And so, if I acted really quickly,
00:03:56.890 --> 00:04:01.400
I would've given them my
Amazon username and password.
00:04:01.400 --> 00:04:04.510
So, be on the lookout for
these phishing attacks,
00:04:04.510 --> 00:04:07.890
and the main way to catch them
is be skeptical of anything
00:04:07.890 --> 00:04:09.250
that's talking about fraud,
00:04:09.250 --> 00:04:12.267
about something that you
would scare you and say,
00:04:12.267 --> 00:04:14.850
"Hey, do I really think
this is happening?"
00:04:14.850 --> 00:04:18.020
And then, if you really
think it might be happening,
00:04:18.020 --> 00:04:22.060
verify the email addresses,
verify the web addresses
00:04:22.060 --> 00:04:25.190
that they're really coming
from who they say they're from.
00:04:25.190 --> 00:04:29.160
And it doesn't matter if the
name is @somethingpaypal.com.
00:04:29.160 --> 00:04:31.330
You have to look at the
actual email address
00:04:31.330 --> 00:04:33.030
and it doesn't matter what it says here.
00:04:33.030 --> 00:04:35.510
It matters what the actual URL is
00:04:35.510 --> 00:04:40.010
that it clicks to to make
sure that it isn't fishy.
00:04:40.010 --> 00:04:43.033
No pun intended, or actually,
that pun was intended.
|
Tracking users on the Internet | https://www.youtube.com/watch?v=StoIE3hhSqA | vtt | https://www.youtube.com/api/timedtext?v=StoIE3hhSqA&ei=uVWUZbrVG4a5vdIPg_CE4Aw&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245289&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=28AC916B9C425BD21F9A3719693FF8598665C72C.B2FE9EBBF9A4E65D1761205DDB5A7F1F015DB9F4&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.320 --> 00:00:01.490
- So there's a bunch
00:00:01.490 --> 00:00:04.130
of reasons why a website
might want to track you.
00:00:04.130 --> 00:00:05.420
And depending on your opinion,
00:00:05.420 --> 00:00:06.840
you might think some
of these are reasonable
00:00:06.840 --> 00:00:09.460
and you might think some
of them are unreasonable.
00:00:09.460 --> 00:00:10.450
Just to understand,
00:00:10.450 --> 00:00:12.730
imagine if you were to
go to say Khan Academy
00:00:12.730 --> 00:00:14.060
and you were to do some work,
00:00:14.060 --> 00:00:15.610
well it might be nice that if you were
00:00:15.610 --> 00:00:17.720
to come back another day that,
00:00:17.720 --> 00:00:19.020
that work isn't lost.
00:00:19.020 --> 00:00:20.680
And so that might be a reason
00:00:20.680 --> 00:00:23.980
why you would want Khan
Academy to know who you are.
00:00:23.980 --> 00:00:25.080
Now, there's a bunch
00:00:25.080 --> 00:00:27.200
of different ways that this could happen.
00:00:27.200 --> 00:00:28.340
The most obvious way is
00:00:28.340 --> 00:00:30.840
by having an account with
a username and a password.
00:00:30.840 --> 00:00:32.980
So when you type in your
username and password
00:00:32.980 --> 00:00:34.820
the site knows exactly who you are.
00:00:34.820 --> 00:00:36.820
It can retrieve your data from a database
00:00:36.820 --> 00:00:39.490
and then you can pick up
right where you left off.
00:00:39.490 --> 00:00:41.300
That's probably the
most obvious to people.
00:00:41.300 --> 00:00:44.410
And it's also the most
obvious how to not be tracked
00:00:44.410 --> 00:00:46.410
in that way is that you log out.
00:00:46.410 --> 00:00:48.260
But just because you logged out or just
00:00:48.260 --> 00:00:50.940
because you don't have a username
and password doesn't mean
00:00:50.940 --> 00:00:53.330
that you can't be tracked by a site.
00:00:53.330 --> 00:00:55.400
There's several other
ways that can be tracked
00:00:55.400 --> 00:00:56.780
that you should know about
00:00:56.780 --> 00:00:59.910
and also know how to
undo them if possible.
00:00:59.910 --> 00:01:03.080
Another way is leveraging
something called cookies.
00:01:03.080 --> 00:01:06.200
Cookies, even if you don't
have an account on a site,
00:01:06.200 --> 00:01:09.490
most web browsers are
going to allow the website
00:01:09.490 --> 00:01:12.810
to place a little bit of
text on your computer.
00:01:12.810 --> 00:01:14.360
So the browser, which is running
00:01:14.360 --> 00:01:16.260
on your computer is gonna place it,
00:01:16.260 --> 00:01:17.760
so that next time your browser goes
00:01:17.760 --> 00:01:19.480
to that site again, the site will say,
00:01:19.480 --> 00:01:22.130
oh this is the same person
whose cookie I put there.
00:01:22.130 --> 00:01:24.060
And then there might that
cookie might have a little bit
00:01:24.060 --> 00:01:26.430
of data associated with it and say, okay
00:01:26.430 --> 00:01:28.461
there could be some useful things.
00:01:28.461 --> 00:01:29.294
We can pick up where we left off.
00:01:29.294 --> 00:01:31.120
We can customize for what
you were looking for.
00:01:31.120 --> 00:01:32.840
Or you might say that's
a little bit creepy,
00:01:32.840 --> 00:01:34.570
that a site that I
didn't get permission to
00:01:34.570 --> 00:01:35.880
is able to keep track of me.
00:01:35.880 --> 00:01:38.470
And so you might want
to delete your cookies
00:01:38.470 --> 00:01:41.210
which your browser will allow you to do.
00:01:41.210 --> 00:01:44.410
Now cookies, as I saId,
they have their benefits.
00:01:44.410 --> 00:01:45.243
This one of the reasons
00:01:45.243 --> 00:01:47.520
why you can often stay logged
00:01:47.520 --> 00:01:50.120
into a website because the website says,
00:01:50.120 --> 00:01:50.953
oh, this is a cookie.
00:01:50.953 --> 00:01:53.830
This is the person who keeps logging in.
00:01:53.830 --> 00:01:55.490
You might want the personalization
00:01:55.490 --> 00:01:56.820
of the advertisements
00:01:56.820 --> 00:01:59.280
or any other customizations
without logging in.
00:01:59.280 --> 00:02:01.040
And that's where a cookie could be useful.
00:02:01.040 --> 00:02:03.710
But if you don't want it, of
course, you can delete it.
00:02:03.710 --> 00:02:05.530
Now, another way that a
website can keep track
00:02:05.530 --> 00:02:06.840
is your IP address.
00:02:06.840 --> 00:02:08.490
When your web browser
00:02:08.490 --> 00:02:11.090
which is running on your
computer or on your phone
00:02:12.100 --> 00:02:13.540
wants to look at a website,
00:02:13.540 --> 00:02:15.100
it sends a request to that website,
00:02:15.100 --> 00:02:16.970
and then that request sends the data,
00:02:16.970 --> 00:02:18.400
sends the website back.
00:02:18.400 --> 00:02:20.400
And so in order to send the data back
00:02:20.400 --> 00:02:23.170
it needs an address for your
phone or for your computer
00:02:23.170 --> 00:02:26.340
and that's going to be in
the form of an IP address.
00:02:26.340 --> 00:02:29.610
Now you can imagine if that
site knows your IP address
00:02:29.610 --> 00:02:31.350
and then if you were to
come from the same device
00:02:31.350 --> 00:02:33.270
with the same IP address,
again, it'll say, okay,
00:02:33.270 --> 00:02:34.820
it's at least the same device.
00:02:34.820 --> 00:02:36.220
Maybe it's the same person.
00:02:36.220 --> 00:02:38.810
And then they might be able
to track you in that way.
00:02:38.810 --> 00:02:39.870
Once again, it might be
00:02:39.870 --> 00:02:42.030
for some good uses, like customization
00:02:42.030 --> 00:02:45.580
or maybe it's things that you
aren't so comfortable with.
00:02:45.580 --> 00:02:48.020
Now, what gets extra interesting
00:02:48.020 --> 00:02:50.380
and might be useful or not useful,
00:02:50.380 --> 00:02:53.140
depending on your point
of view is that it's not
00:02:53.140 --> 00:02:56.100
necessarily just your
relationship with one website.
00:02:56.100 --> 00:02:59.380
For example, you might have an
advertiser that puts cookies
00:02:59.380 --> 00:03:02.280
on a bunch of websites,
and so can keep track
00:03:02.280 --> 00:03:04.740
of you as you go from site to site.
00:03:04.740 --> 00:03:07.520
And so then it's getting, at least for me,
00:03:07.520 --> 00:03:10.320
I don't like the fact that people can see
00:03:10.320 --> 00:03:12.800
how I'm moving around on the internet.
00:03:12.800 --> 00:03:15.230
Or I remember recently I was looking
00:03:15.230 --> 00:03:19.440
for a mountain bike and I
did it on one eCommerce site.
00:03:19.440 --> 00:03:20.350
And then all of a sudden it seemed
00:03:20.350 --> 00:03:21.450
like the whole internet knew
00:03:21.450 --> 00:03:22.790
that I wanted to buy a mountain bike.
00:03:22.790 --> 00:03:24.220
I didn't end up buying a mountain bike.
00:03:24.220 --> 00:03:25.362
Now some of you might say, that's nice.
00:03:25.362 --> 00:03:27.670
You know, the internet knows
I want a mountain bike.
00:03:27.670 --> 00:03:29.570
I'd like to keep being presented
00:03:29.570 --> 00:03:31.230
with ads on mountain bikes.
00:03:31.230 --> 00:03:32.670
Some of you might say,
hey, that's not so cool.
00:03:32.670 --> 00:03:34.530
It was just, well, you
know, a random search I did.
00:03:34.530 --> 00:03:35.363
And it's kind of weird
00:03:35.363 --> 00:03:37.250
that the internet is starting
to build this profile of me
00:03:37.250 --> 00:03:40.110
of someone who might be in
the market for mountain bikes.
00:03:40.110 --> 00:03:43.880
And so once again, deleting
your cookies can go a long way
00:03:43.880 --> 00:03:45.020
to preventing that type of thing,
00:03:45.020 --> 00:03:46.620
if you're uncomfortable with it.
00:03:46.620 --> 00:03:49.430
And then IP addresses, that's
a little bit harder to hide.
00:03:49.430 --> 00:03:51.710
Sometimes you have dynamic IP addresses
00:03:51.710 --> 00:03:55.190
sometimes it changes, but the clearest way
00:03:55.190 --> 00:03:57.060
of protecting your IP address is
00:03:57.060 --> 00:03:58.950
if you use something like
a virtual private network
00:03:58.950 --> 00:04:02.450
which does get a little bit more complex.
00:04:02.450 --> 00:04:03.640
Now related to all of this,
00:04:03.640 --> 00:04:05.100
some of you also might be thinking
00:04:05.100 --> 00:04:06.890
about being tracked when you do a search.
00:04:06.890 --> 00:04:07.980
You might see that,
00:04:07.980 --> 00:04:10.170
hey, these suggested searches
00:04:10.170 --> 00:04:11.710
that the site is giving,
00:04:11.710 --> 00:04:14.010
it seems like it's kind of specific to me.
00:04:14.010 --> 00:04:16.080
And that's because in many cases it is.
00:04:16.080 --> 00:04:17.890
The search engine probably
00:04:17.890 --> 00:04:21.350
has placed cookies, or it's
keeping with an IP address
00:04:21.350 --> 00:04:23.900
of things that you have
searched for before.
00:04:23.900 --> 00:04:25.940
And the things that you have clicked on.
00:04:25.940 --> 00:04:27.410
And so it could use that maybe
00:04:27.410 --> 00:04:28.990
to give you different search results,
00:04:28.990 --> 00:04:31.430
maybe to change what the auto-complete is.
00:04:31.430 --> 00:04:34.450
It also might be keeping
track of a search history.
00:04:34.450 --> 00:04:36.270
So the search history could be useful,
00:04:36.270 --> 00:04:37.150
if you wanna look
00:04:37.150 --> 00:04:39.340
at other sites that
you have been to before
00:04:39.340 --> 00:04:40.910
or you might not want that around.
00:04:40.910 --> 00:04:45.190
You might not want the
site or someone else
00:04:45.190 --> 00:04:47.500
who if you just happen
to be using your computer
00:04:47.500 --> 00:04:49.130
to see what you've been searching for.
00:04:49.130 --> 00:04:51.410
So most browsers, sorry
00:04:51.410 --> 00:04:54.650
most search engines are
going to let you delete that.
00:04:54.650 --> 00:04:56.403
So there's a lot more to it.
00:04:56.403 --> 00:04:59.540
This is just kind of
the tip of the iceberg,
00:04:59.540 --> 00:05:02.150
but think about how you
may or may not be tracked
00:05:02.150 --> 00:05:04.600
and think about how you may
or may not want to be tracked.
00:05:04.600 --> 00:05:06.140
And good hygiene is,
00:05:06.140 --> 00:05:08.770
especially if you're at a public
computer log out of things.
00:05:08.770 --> 00:05:11.720
That's also so other people
can't use use your account,
00:05:11.720 --> 00:05:12.730
really be thoughtful about
00:05:12.730 --> 00:05:15.000
whether you even want to
create an account for a site.
00:05:15.000 --> 00:05:16.820
Is this something that you really need?
00:05:16.820 --> 00:05:18.560
What are going to be the benefits for you?
00:05:18.560 --> 00:05:20.970
Think about whether you
want to accept cookies?
00:05:20.970 --> 00:05:23.810
I would recommend deleting
cookies pretty regularly.
00:05:23.810 --> 00:05:24.840
It might have some negatives.
00:05:24.840 --> 00:05:26.470
You might have to re-log into a few sites,
00:05:26.470 --> 00:05:28.550
but there's probably a
lot of other shady sites
00:05:28.550 --> 00:05:31.740
that no longer can
track what you're doing.
00:05:31.740 --> 00:05:33.720
But even if you do all of those things
00:05:33.720 --> 00:05:36.513
still be very careful
and very conscientious.
|
Importance of Data Security | https://www.youtube.com/watch?v=fU4vsLeh1So | vtt | https://www.youtube.com/api/timedtext?v=fU4vsLeh1So&ei=uVWUZYeCG9LTxN8P1vKvkAQ&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245289&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=CA70114CD77167BBBEDE6881F3BBDC7E9F7ABAC3.58966121D05BD4094DC22A0BD174C7708FEFB32A&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:01.370 --> 00:00:03.610
- I'm going to make a bold prediction.
00:00:03.610 --> 00:00:07.350
You probably don't like
people stealing your identity
00:00:07.350 --> 00:00:09.840
which allows them to steal your money.
00:00:09.840 --> 00:00:12.620
Or maybe tell the whole
universe what you're up to
00:00:12.620 --> 00:00:14.800
and being able to track
you and your family,
00:00:14.800 --> 00:00:16.800
and compromise your security.
00:00:16.800 --> 00:00:18.950
These don't feel like good things.
00:00:18.950 --> 00:00:21.780
And so, if that is true
of you, it's true of me.
00:00:21.780 --> 00:00:23.330
I don't like any of those things.
00:00:23.330 --> 00:00:26.540
I wanna keep my private
information private,
00:00:26.540 --> 00:00:29.460
then you should care about data security.
00:00:29.460 --> 00:00:32.020
And that's what we're
going to do in this unit.
00:00:32.020 --> 00:00:32.910
You're gonna learn a lot
00:00:32.910 --> 00:00:35.470
about personally identifiable information.
00:00:35.470 --> 00:00:36.910
Your name is one example,
00:00:36.910 --> 00:00:39.070
but also things like your
social security number,
00:00:39.070 --> 00:00:42.050
or things that are indirectly,
personally identifiable
00:00:42.050 --> 00:00:44.630
like your address, or your phone number,
00:00:44.630 --> 00:00:46.420
why that's important.
00:00:46.420 --> 00:00:47.960
And then we're going to learn the ways
00:00:47.960 --> 00:00:50.100
that people are going to
try to get ahold of it,
00:00:50.100 --> 00:00:51.670
and why they want to get ahold of it.
00:00:51.670 --> 00:00:54.430
Because they might wanna misrepresent you,
00:00:54.430 --> 00:00:57.180
or or publish things
about you on the Internet,
00:00:57.180 --> 00:00:59.030
or control your presence on the internet,
00:00:59.030 --> 00:01:03.430
or steal money from you or from
others that you care about.
00:01:03.430 --> 00:01:04.330
And then we're going to learn
00:01:04.330 --> 00:01:05.760
about ways to protect from those.
00:01:05.760 --> 00:01:08.110
A lot of that's going to be
behavior change on your part
00:01:08.110 --> 00:01:09.890
to be a little bit more vigilant,
00:01:09.890 --> 00:01:13.360
but also technology ways of
keeping your data secret,
00:01:13.360 --> 00:01:15.650
encrypting your data, authentication,
00:01:15.650 --> 00:01:18.530
making sure that the person
who says they are who they are,
00:01:18.530 --> 00:01:20.530
are actually them.
00:01:20.530 --> 00:01:23.180
So enjoy this unit on data security.
00:01:23.180 --> 00:01:25.620
It isn't just interesting, which it is.
00:01:25.620 --> 00:01:28.400
It could save you a lot of money,
00:01:28.400 --> 00:01:31.023
a lot of pain, and a lot of embarrassment.
|
Personally Identifiable Information (PII) | https://www.youtube.com/watch?v=FwBKZOcn4yI | vtt | https://www.youtube.com/api/timedtext?v=FwBKZOcn4yI&ei=uVWUZZuREaCep-oPq6iAoAE&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245289&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=93D0D241555E902553F18CDFC21D7274AD8848A3.2AA73D1234BAB547742AB6D5A6CEE17D38063127&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.573 --> 00:00:01.710
- Hi everyone.
00:00:01.710 --> 00:00:03.360
Sal Khan here from Khan academy.
00:00:03.360 --> 00:00:06.250
My Social Security Number is 857,
00:00:06.250 --> 00:00:07.180
- 32
00:00:07.180 --> 00:00:08.133
- 5567.
00:00:10.600 --> 00:00:11.433
No, it's not.
00:00:11.433 --> 00:00:14.320
I wouldn't tell you my Social
Security Number like that.
00:00:14.320 --> 00:00:15.153
And that's because
00:00:15.153 --> 00:00:20.153
it is personally identifiable
information, or PII.
00:00:20.360 --> 00:00:22.630
And there's a reason why
you want to keep that
00:00:22.630 --> 00:00:26.493
to yourself, or at least
limit who has access to PII.
00:00:27.630 --> 00:00:31.950
Because if someone has access,
they can expose your privacy,
00:00:31.950 --> 00:00:34.290
tell the world where you
live, they could track you
00:00:34.290 --> 00:00:36.310
and they could tell the
world what you've been up to,
00:00:36.310 --> 00:00:37.560
maybe when you should be working
00:00:37.560 --> 00:00:38.740
what websites you're visiting,
00:00:38.740 --> 00:00:43.380
or, even worse, potentially,
they could steal your identity,
00:00:43.380 --> 00:00:44.790
take money out of your bank account,
00:00:44.790 --> 00:00:46.410
take a credit card in your name,
00:00:46.410 --> 00:00:48.493
do some other form of identity theft
00:00:48.493 --> 00:00:52.890
that could be embarrassing,
or super costly.
00:00:52.890 --> 00:00:55.340
So, if you have some type of a service,
00:00:55.340 --> 00:00:57.850
either online or otherwise,
that's asking for something
00:00:57.850 --> 00:00:59.650
like your Social Security Number,
00:00:59.650 --> 00:01:02.840
or your birthday, which might
be a little bit more indirect,
00:01:02.840 --> 00:01:05.603
or your email address,
or your phone number,
00:01:05.603 --> 00:01:07.430
you might ask why.
00:01:07.430 --> 00:01:09.230
Sometimes there's a legitimate reason
00:01:09.230 --> 00:01:10.197
why they need to know these things
00:01:10.197 --> 00:01:13.570
but many times, I'd argue
even most of the time,
00:01:13.570 --> 00:01:15.350
there might not be a legitimate reason.
00:01:15.350 --> 00:01:16.900
And so you need to ask yourself, well
00:01:16.900 --> 00:01:18.075
what are they going to do with it?
00:01:18.075 --> 00:01:21.220
And if you don't feel comfortable
giving that information,
00:01:21.220 --> 00:01:23.960
ask yourself, do you
really need that service?
00:01:23.960 --> 00:01:26.200
So think seriously about your PII.
00:01:26.200 --> 00:01:28.640
Unfortunately, bad actors
on the Internet are coming
00:01:28.640 --> 00:01:32.630
up with new ways of
leveraging both direct PII,
00:01:32.630 --> 00:01:34.300
personally identifiable information
00:01:34.300 --> 00:01:35.700
like Social Security Numbers,
00:01:35.700 --> 00:01:38.360
even biometrics, even your name,
00:01:38.360 --> 00:01:41.760
and indirect measures, or
indirect pieces of PII,
00:01:41.760 --> 00:01:46.430
like your birthday, or your
address, or your email address,
00:01:46.430 --> 00:01:48.640
or your phone number,
that can be put together
00:01:48.640 --> 00:01:51.070
to do shady things with your identity.
00:01:51.070 --> 00:01:53.333
So be very careful.
|
Lunar eclipses | https://www.youtube.com/watch?v=WXSHQK56Bfs | vtt | https://www.youtube.com/api/timedtext?v=WXSHQK56Bfs&ei=uVWUZdzyELinp-oPxYSROA&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245289&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=C3D48ED2EF040EEBC610745C6A5237F4359EF7DC.A57384916EED08C5BCA05E4693B5EBDE99B23068&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.120 --> 00:00:01.720
- [Narrator] Have you
ever seen the full moon
00:00:01.720 --> 00:00:03.490
appear to change from this,
00:00:03.490 --> 00:00:05.490
to this, to this
00:00:05.490 --> 00:00:07.570
all in a couple hours?
00:00:07.570 --> 00:00:10.070
If so, you've witnessed a lunar eclipse.
00:00:10.070 --> 00:00:12.100
The word eclipse comes from a Greek word
00:00:12.100 --> 00:00:13.170
meaning "to leave."
00:00:13.170 --> 00:00:14.850
For centuries, people have marveled
00:00:14.850 --> 00:00:16.340
at how the full moon appears to leave
00:00:16.340 --> 00:00:17.820
during a lunar eclipse.
00:00:17.820 --> 00:00:19.770
The Incas believed that
lunar eclipses happened
00:00:19.770 --> 00:00:21.820
when a giant jaguar ate the full moon.
00:00:21.820 --> 00:00:23.790
It turns out, lunar eclipses happen
00:00:23.790 --> 00:00:26.130
when the moon is covered
by Earth's shadow.
00:00:26.130 --> 00:00:27.220
We can only see the moon
00:00:27.220 --> 00:00:28.960
because it reflects light from the sun.
00:00:28.960 --> 00:00:31.360
The moon doesn't generate
any light of its own.
00:00:31.360 --> 00:00:33.730
The sun lights up half of
the sphere of the moon.
00:00:33.730 --> 00:00:35.780
When Earth is between
the sun and the moon,
00:00:35.780 --> 00:00:38.260
we can see the entire
lit part of the moon.
00:00:38.260 --> 00:00:40.540
We call this the full moon.
00:00:40.540 --> 00:00:42.200
But sometimes during a full moon,
00:00:42.200 --> 00:00:44.620
Earth, the moon, and the sun all line up
00:00:44.620 --> 00:00:46.950
in such a way that Earth
casts a shadow onto the moon.
00:00:46.950 --> 00:00:49.460
This creates a lunar eclipse.
00:00:49.460 --> 00:00:50.670
Lunar eclipses can be seen
00:00:50.670 --> 00:00:52.520
from anywhere on the night side of Earth.
00:00:52.520 --> 00:00:54.720
The two most dramatic
types of lunar eclipses
00:00:54.720 --> 00:00:56.120
are total and partial.
00:00:56.120 --> 00:00:57.522
During a total lunar eclipse,
00:00:57.522 --> 00:01:00.100
Earth's shadow completely covers the moon.
00:01:00.100 --> 00:01:02.640
This means that no direct
sunlight is reaching the moon.
00:01:02.640 --> 00:01:05.780
However, the moon is still
visible during the eclipse.
00:01:05.780 --> 00:01:06.780
Why is this?
00:01:06.780 --> 00:01:08.820
As sunlight passes through our atmosphere,
00:01:08.820 --> 00:01:10.610
some of it gets bent slightly
00:01:10.610 --> 00:01:11.820
allowing it to reach the moon
00:01:11.820 --> 00:01:13.750
as indirect sunlight.
00:01:13.750 --> 00:01:16.180
Most of the light that
gets bent is red or orange,
00:01:16.180 --> 00:01:18.120
meaning that the moon
appears reddish orange
00:01:18.120 --> 00:01:19.480
during the eclipse.
00:01:19.480 --> 00:01:21.010
During a partial lunar eclipse,
00:01:21.010 --> 00:01:23.540
Earth's shadow only
partially covers the moon.
00:01:23.540 --> 00:01:26.420
So some direct sunlight is
still reaching the moon.
00:01:26.420 --> 00:01:28.850
Lunar eclipses only
happen during a full moon
00:01:28.850 --> 00:01:30.840
since it's the only
time in the moon's orbit
00:01:30.840 --> 00:01:32.950
where Earth is between
the sun and the moon.
00:01:32.950 --> 00:01:35.570
And you might be wondering,
"why isn't there a lunar eclipse
00:01:35.570 --> 00:01:37.010
during every full moon?"
00:01:37.010 --> 00:01:39.070
Well, the moon's orbit around Earth
00:01:39.070 --> 00:01:41.480
is tilted relative to
Earth's orbit around the sun.
00:01:41.480 --> 00:01:42.420
This means that the moon
00:01:42.420 --> 00:01:45.600
often passes just above or
just below Earth's shadow.
00:01:45.600 --> 00:01:47.600
Partial lunar eclipses
happen when the sun,
00:01:47.600 --> 00:01:50.730
the moon, and Earth almost,
but not quite exactly,
00:01:50.730 --> 00:01:53.360
line up so that the moon
is only partially covered
00:01:53.360 --> 00:01:54.450
by Earth's shadow.
00:01:54.450 --> 00:01:56.880
Total lunar eclipses
happen only when the sun,
00:01:56.880 --> 00:01:59.540
the moon, and Earth all line up precisely.
00:01:59.540 --> 00:02:01.900
So if you ever get to see a lunar eclipse,
00:02:01.900 --> 00:02:04.510
you can thank our planet for
blocking the moon's sunlight
00:02:04.510 --> 00:02:06.760
and letting us enjoy
the celestial spectacle.
|
Cellular respiration | https://www.youtube.com/watch?v=1RXk1NJpRDI | vtt | https://www.youtube.com/api/timedtext?v=1RXk1NJpRDI&ei=uVWUZYzkH6uomLAPlLGnkAc&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245289&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=D72840FE374F255F7F9A85EA43662DAA30EE5D0D.C607F88352B4F962CAF76903E09616B007D28DD0&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.250 --> 00:00:01.770
- [Instructor] So let's
say I was preparing
00:00:01.770 --> 00:00:03.890
to go on a long hike.
00:00:03.890 --> 00:00:06.720
Besides packing water,
dressing for the weather
00:00:06.720 --> 00:00:08.060
and mapping my route,
00:00:08.060 --> 00:00:10.520
I'd probably also want to eat a snack
00:00:10.520 --> 00:00:13.450
before leaving to make
sure I have enough energy
00:00:13.450 --> 00:00:14.550
for the hike.
00:00:14.550 --> 00:00:17.710
We as humans need food
to nourish our bodies.
00:00:17.710 --> 00:00:20.880
But how exactly does
that food give us energy?
00:00:20.880 --> 00:00:24.280
How does something like an
apple or a piece of chocolate
00:00:24.280 --> 00:00:27.630
get converted into something
our bodies can use?
00:00:27.630 --> 00:00:29.770
The answer to this question can be found
00:00:29.770 --> 00:00:32.630
in a process called cellular respiration.
00:00:32.630 --> 00:00:35.920
Which is how organisms get
their energy from food.
00:00:35.920 --> 00:00:36.930
In other words,
00:00:36.930 --> 00:00:40.120
cellular respiration
helps make life possible.
00:00:40.120 --> 00:00:42.250
It's happening right now in your cells
00:00:42.250 --> 00:00:43.290
and in mine,
00:00:43.290 --> 00:00:45.860
in my little brothers pet hamster cells
00:00:45.860 --> 00:00:48.760
and in the cells of the
tree outside the window.
00:00:48.760 --> 00:00:50.900
It's providing all of us with the energy
00:00:50.900 --> 00:00:52.560
that we need to function.
00:00:52.560 --> 00:00:54.510
So let's dive into this process
00:00:54.510 --> 00:00:57.090
to find out more about how it works.
00:00:57.090 --> 00:01:00.700
Cellular respiration is a
series of chemical reactions
00:01:00.700 --> 00:01:04.110
that happen in an organized
way inside our cells.
00:01:04.110 --> 00:01:06.310
It's these chemical reactions that result
00:01:06.310 --> 00:01:10.400
in an overall release of
energy that our bodies can use.
00:01:10.400 --> 00:01:11.740
Although cellular respiration
00:01:11.740 --> 00:01:15.240
involves many chemical
reactions, this entire process
00:01:15.240 --> 00:01:17.740
for plants and animals
can be summarized here
00:01:17.740 --> 00:01:19.380
by this equation.
00:01:19.380 --> 00:01:22.520
On the left side of this
equation are the inputs;
00:01:22.520 --> 00:01:25.060
Glucose, which is a type of sugar,
00:01:25.060 --> 00:01:26.500
and oxygen.
00:01:26.500 --> 00:01:29.630
Glucose comes from our
food and oxygen comes
00:01:29.630 --> 00:01:31.690
from the air we breathe.
00:01:31.690 --> 00:01:34.310
The right side of this
equation shows the outputs,
00:01:34.310 --> 00:01:36.700
carbon dioxide and water.
00:01:36.700 --> 00:01:39.220
The air in the middle shows
that during the process
00:01:39.220 --> 00:01:40.830
of cellular respiration,
00:01:40.830 --> 00:01:43.850
glucose and oxygen molecules
are are broken apart
00:01:43.850 --> 00:01:46.060
and their atoms are rearranged
00:01:46.060 --> 00:01:49.130
to eventually form
carbon dioxide and water.
00:01:49.130 --> 00:01:51.430
This whole process releases energy,
00:01:51.430 --> 00:01:55.020
similar to how firewood
releases energy as it burns.
00:01:55.020 --> 00:01:59.010
Also, no atoms are lost
during cellular respiration.
00:01:59.010 --> 00:02:01.700
You can see the same
number of each type of atom
00:02:01.700 --> 00:02:04.320
on both sides of the arrow, for example,
00:02:04.320 --> 00:02:06.720
six carbon atoms on both sides.
00:02:06.720 --> 00:02:10.030
It's similar to how you could
take apart a brick house
00:02:10.030 --> 00:02:13.650
and use those bricks to build
something else, like a bridge.
00:02:13.650 --> 00:02:15.710
You're not throwing
away any of the bricks,
00:02:15.710 --> 00:02:18.790
but instead you're creating
something new out of them.
00:02:18.790 --> 00:02:22.100
So we know that cellular
respiration involves a series
00:02:22.100 --> 00:02:23.650
of chemical reactions,
00:02:23.650 --> 00:02:26.720
but where in the cell
do these steps happen?
00:02:26.720 --> 00:02:29.580
To find out, let's walk
through the process together.
00:02:29.580 --> 00:02:32.010
After eating, your food is broken down
00:02:32.010 --> 00:02:34.870
into small molecules during digestion.
00:02:34.870 --> 00:02:37.670
These small molecules
which include glucose
00:02:37.670 --> 00:02:39.520
can enter your cells.
00:02:39.520 --> 00:02:41.950
Then cellular respiration can begin.
00:02:41.950 --> 00:02:45.120
The first set of chemical
reactions happen in the cytosol,
00:02:45.120 --> 00:02:47.860
which is the jelly-like
fluid containing all
00:02:47.860 --> 00:02:49.110
of the cells organelles,
00:02:49.110 --> 00:02:51.840
and they involve glucose as an input.
00:02:51.840 --> 00:02:54.860
The rest of the reactions
happen in mitochondria,
00:02:54.860 --> 00:02:58.380
with oxygen as an input and carbon dioxide
00:02:58.380 --> 00:03:00.380
and water as outputs.
00:03:00.380 --> 00:03:02.710
Together, these chemical reactions result
00:03:02.710 --> 00:03:05.600
in an overall release of energy.
00:03:05.600 --> 00:03:07.150
It might be a little mind boggling
00:03:07.150 --> 00:03:09.680
for you to think about how
the food we eat provides
00:03:09.680 --> 00:03:11.130
the energy our bodies need
00:03:11.130 --> 00:03:13.630
to carry out all of lives processes.
00:03:13.630 --> 00:03:15.460
And I know it was for me.
00:03:15.460 --> 00:03:18.740
After all, it's not every day
you take a bite of an apple
00:03:18.740 --> 00:03:20.860
and wonder how that apple's molecules
00:03:20.860 --> 00:03:23.270
are rearranged inside your body.
00:03:23.270 --> 00:03:24.680
What's important to know though,
00:03:24.680 --> 00:03:26.270
is that cellular respiration
00:03:26.270 --> 00:03:29.410
is the way our cells get usable energy.
00:03:29.410 --> 00:03:30.930
Through cellular respiration,
00:03:30.930 --> 00:03:32.880
you and I get the energy that we need
00:03:32.880 --> 00:03:34.670
to do the things we want to do,
00:03:34.670 --> 00:03:37.260
including accomplishing our goals.
00:03:37.260 --> 00:03:39.430
So, the next time you feel
proud of your yourself
00:03:39.430 --> 00:03:43.090
for finishing a big hike
or acing your biology quiz,
00:03:43.090 --> 00:03:45.883
make sure to thank your mitochondria.
|
Food and energy in organisms | https://www.youtube.com/watch?v=wPhjCn9kq5M | vtt | https://www.youtube.com/api/timedtext?v=wPhjCn9kq5M&ei=uVWUZYH8Gc2Cp-oP78CJwAo&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245289&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=58D444EF53F301E13D10771C7D35A3A143BE80A2.D4924CE164175C0F373F609E5E9FBC26DF013FB3&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.140 --> 00:00:02.220
- [Instructor] Hey,
quick question for you.
00:00:02.220 --> 00:00:04.670
You ever look at a person's baby pictures
00:00:04.670 --> 00:00:08.300
and wonder how people go from
being small to, well, big?
00:00:08.300 --> 00:00:10.040
I mean, yes, I get it.
00:00:10.040 --> 00:00:12.450
People grow up, but
here, I'm thinking more
00:00:12.450 --> 00:00:14.540
on the level of the atoms and molecules
00:00:14.540 --> 00:00:15.640
that make up the body
00:00:15.640 --> 00:00:19.090
because A, I'm a scientist
and that's kind of what we do,
00:00:19.090 --> 00:00:21.560
and then also B, because after all,
00:00:21.560 --> 00:00:23.650
all the changes we see
on these larger scales
00:00:23.650 --> 00:00:26.410
are just reflections of
very many changes occurring
00:00:26.410 --> 00:00:28.360
on the molecular scale.
00:00:28.360 --> 00:00:30.790
And so if you think about it that way,
00:00:30.790 --> 00:00:33.040
then it's likely reasonable to assume
00:00:33.040 --> 00:00:35.230
that because the adult's body is bigger,
00:00:35.230 --> 00:00:38.020
it has more molecules
and/or larger molecules
00:00:38.020 --> 00:00:39.200
than the baby's body.
00:00:39.200 --> 00:00:42.960
And so this means that there
are some molecules in this baby
00:00:42.960 --> 00:00:46.200
and those molecules are
interacting and combining
00:00:46.200 --> 00:00:48.890
with some other source
of molecules in the world
00:00:48.890 --> 00:00:50.920
in order to become this adult.
00:00:50.920 --> 00:00:52.210
And generally speaking,
00:00:52.210 --> 00:00:55.200
the source of those molecules
is going to be our diet,
00:00:55.200 --> 00:00:56.660
AKA our food.
00:00:56.660 --> 00:00:58.540
And to kind of understand this,
00:00:58.540 --> 00:01:00.690
we can actually make a comparison here
00:01:00.690 --> 00:01:03.360
between food and wood.
00:01:03.360 --> 00:01:05.330
So what I mean by that
00:01:05.330 --> 00:01:06.760
is that the molecules in food
00:01:06.760 --> 00:01:09.250
interact with the molecules on our bodies
00:01:09.250 --> 00:01:11.160
in two primary ways.
00:01:11.160 --> 00:01:14.720
The first is as a source of
molecular building blocks,
00:01:14.720 --> 00:01:15.553
or in other words,
00:01:15.553 --> 00:01:18.690
molecules the body can use
to build new structures.
00:01:18.690 --> 00:01:20.240
And the second is going to be
00:01:20.240 --> 00:01:22.360
as a source of molecules for fuel,
00:01:22.360 --> 00:01:26.560
much like a campfire or
firewood, like what we have here.
00:01:26.560 --> 00:01:27.990
But in order to understand
00:01:27.990 --> 00:01:30.000
how and why this can happen,
00:01:30.000 --> 00:01:33.820
we need to briefly discuss
the molecular basis of food.
00:01:33.820 --> 00:01:35.530
So what are the molecules in food?
00:01:35.530 --> 00:01:36.670
Let me introduce you.
00:01:36.670 --> 00:01:38.090
All right, 'cause generally speaking,
00:01:38.090 --> 00:01:41.520
food is made up of these
three classes of molecules.
00:01:41.520 --> 00:01:43.750
First up are fats,
00:01:43.750 --> 00:01:45.550
then we've got sugars,
00:01:45.550 --> 00:01:48.230
and finally some protein.
00:01:48.230 --> 00:01:51.490
I'd imagine some of these
sound reasonably familiar.
00:01:51.490 --> 00:01:53.760
These molecules are made basically
00:01:53.760 --> 00:01:55.440
from just a few elements.
00:01:55.440 --> 00:01:59.300
So this is color-coded and
the gray balls are carbon.
00:01:59.300 --> 00:02:01.610
The white ones are hydrogen.
00:02:01.610 --> 00:02:02.600
Those are the big ones.
00:02:02.600 --> 00:02:04.030
So most of life's molecules
00:02:04.030 --> 00:02:06.350
are made mostly of carbon and hydrogen.
00:02:06.350 --> 00:02:09.040
But we've also got oxygen here in red
00:02:09.040 --> 00:02:10.740
and nitrogen in blue,
00:02:10.740 --> 00:02:12.630
those are the other two big ones.
00:02:12.630 --> 00:02:13.570
And every now and then,
00:02:13.570 --> 00:02:15.880
we'll also find small amounts
of some other elements,
00:02:15.880 --> 00:02:18.210
like this sulfur here in yellow.
00:02:18.210 --> 00:02:20.110
But the super interesting part here
00:02:20.110 --> 00:02:23.050
is that these are actually
the same exact elements
00:02:23.050 --> 00:02:26.020
that make up most of
the cells in your body.
00:02:26.020 --> 00:02:27.500
So you may notice on this right-hand side
00:02:27.500 --> 00:02:30.380
the same colors is what
we have on the left.
00:02:30.380 --> 00:02:33.930
So this is where the whole
Molecular Lumber thing comes in.
00:02:33.930 --> 00:02:36.190
Our cells can take food
00:02:36.190 --> 00:02:38.880
and break it down into
small building blocks
00:02:38.880 --> 00:02:40.680
and then use those building blocks
00:02:40.680 --> 00:02:43.130
in order to build new
structures in our body.
00:02:43.130 --> 00:02:45.410
So is how we grow.
00:02:45.410 --> 00:02:48.000
This is how babies become adults.
00:02:48.000 --> 00:02:50.320
Turns out, we actually are what we eat.
00:02:50.320 --> 00:02:52.140
It's pretty amazing.
00:02:52.140 --> 00:02:54.090
All right, but before we get too excited,
00:02:54.090 --> 00:02:54.923
let's bring it in.
00:02:54.923 --> 00:02:56.880
So let's switch gears for a second here
00:02:56.880 --> 00:02:58.830
to talk about the other side of things
00:02:58.830 --> 00:03:02.170
because I told you before
that food is like wood.
00:03:02.170 --> 00:03:04.930
And we can use wood to
build new structures, sure.
00:03:04.930 --> 00:03:05.780
But when we need to,
00:03:05.780 --> 00:03:09.250
we can also burn wood to get energy.
00:03:09.250 --> 00:03:10.820
So we can start a campfire.
00:03:10.820 --> 00:03:13.250
And if we do, we know that
we're gonna get some energy
00:03:13.250 --> 00:03:14.530
in the form of light,
00:03:14.530 --> 00:03:16.660
we'll get some energy in the form of heat,
00:03:16.660 --> 00:03:19.300
and maybe some other things like sound.
00:03:19.300 --> 00:03:21.440
And food is actually the same way,
00:03:21.440 --> 00:03:23.610
and so we can take those
same food molecules
00:03:23.610 --> 00:03:25.980
that we broke down before
to get building blocks
00:03:25.980 --> 00:03:30.710
and instead use them as fuel
to generate cellular energy.
00:03:30.710 --> 00:03:33.020
And then we can use that cellular energy
00:03:33.020 --> 00:03:36.170
to fuel all of the building
that we just talked about.
00:03:36.170 --> 00:03:39.500
And likewise, if our cells
work together, which they do,
00:03:39.500 --> 00:03:42.290
they can use this energy
to do things like running,
00:03:42.290 --> 00:03:46.190
thinking, and all the other
things that we humans do.
00:03:46.190 --> 00:03:47.390
All right.
00:03:47.390 --> 00:03:49.620
Let's step back just one more time
00:03:49.620 --> 00:03:51.730
because what we'll see is
that these two processes
00:03:51.730 --> 00:03:53.130
that we've just described,
00:03:53.130 --> 00:03:55.950
so food is lumber and food is fuel
00:03:55.950 --> 00:03:58.500
actually explain so much of life.
00:03:58.500 --> 00:04:00.100
So this is not just us.
00:04:00.100 --> 00:04:02.620
Every living thing on
this planet is doing this.
00:04:02.620 --> 00:04:03.850
So you feed your dog
00:04:03.850 --> 00:04:07.293
to fuel his or her molecular
construction projects as well.
00:04:08.450 --> 00:04:09.820
So right there and then,
00:04:09.820 --> 00:04:12.520
we've already kind of answered
our question from before,
00:04:12.520 --> 00:04:14.060
which, reminder, was:
00:04:14.060 --> 00:04:16.830
how do people go from small to big?
00:04:16.830 --> 00:04:19.420
So what's happening is that
this baby becomes an adult
00:04:19.420 --> 00:04:22.520
by eating food, milk,
formula, gushy stuff,
00:04:22.520 --> 00:04:24.090
I don't know, whatever babies eat.
00:04:24.090 --> 00:04:25.700
And some of the molecules in that food
00:04:25.700 --> 00:04:28.580
will be used as fuel to generate energy,
00:04:28.580 --> 00:04:30.150
and then some of that energy
00:04:30.150 --> 00:04:32.550
will be used to combine food molecules
00:04:32.550 --> 00:04:34.500
with molecules in the baby
00:04:34.500 --> 00:04:37.690
to build up a larger baby, AKA an adult.
00:04:37.690 --> 00:04:39.410
All right, I hope that helps.
00:04:39.410 --> 00:04:40.370
Let's wrap it here.
00:04:40.370 --> 00:04:41.570
See you in the next one.
|
Fossils and rock layers | https://www.youtube.com/watch?v=3LObb5WxMdw | vtt | https://www.youtube.com/api/timedtext?v=3LObb5WxMdw&ei=uVWUZcCrGcXKp-oPrr26yAQ&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245289&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=6545852EDB8B1972DD857995076489FE715FF3DC.76A896707CFFC0320FCE39AC62E98080188F4959&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.033 --> 00:00:02.690
- [Instructor] Have you ever
wanted to travel back in time?
00:00:02.690 --> 00:00:04.720
Would you go meet your younger self?
00:00:04.720 --> 00:00:07.130
Would you go and ride a dinosaur?
00:00:07.130 --> 00:00:09.750
Or would you meticulously
create a timeline
00:00:09.750 --> 00:00:12.610
of the Earth's
4.6-billion-year long history
00:00:12.610 --> 00:00:14.780
based on major geological events?
00:00:14.780 --> 00:00:17.070
Even though geologists
can't go back in time,
00:00:17.070 --> 00:00:19.240
they've been able to do just that.
00:00:19.240 --> 00:00:22.150
Their timeline is called
geologic timescale
00:00:22.150 --> 00:00:24.000
and it breaks up all of Earth's history
00:00:24.000 --> 00:00:26.350
into units called eons and eras.
00:00:26.350 --> 00:00:28.540
And you may be wondering,
"How can we map out
00:00:28.540 --> 00:00:30.720
what happened on Earth
billions of years ago?"
00:00:30.720 --> 00:00:32.620
The answer is rocks.
00:00:32.620 --> 00:00:35.550
Geologists look for clues
in sedimentary rock layers,
00:00:35.550 --> 00:00:37.520
which we call strata.
00:00:37.520 --> 00:00:40.240
The fossil record, which
are the remains of organisms
00:00:40.240 --> 00:00:42.290
that have been preserved in rock layers
00:00:42.290 --> 00:00:45.750
can give us glimpses of
creatures that breathe long ago.
00:00:45.750 --> 00:00:48.050
Also, the difference
in mineral composition
00:00:48.050 --> 00:00:49.280
in different rock layers
00:00:49.280 --> 00:00:51.570
can tell geologists when a volcano erupted
00:00:51.570 --> 00:00:53.340
or an asteroid hit.
00:00:53.340 --> 00:00:55.380
But how did geologists
know when one rock layer
00:00:55.380 --> 00:00:56.850
is older than another?
00:00:56.850 --> 00:00:58.720
Well, when sedimentary rocks form,
00:00:58.720 --> 00:01:01.690
they're deposited in layers,
one on top of the other.
00:01:01.690 --> 00:01:04.460
So unless the layers are
disturbed or turned over,
00:01:04.460 --> 00:01:05.670
the layers at the bottom
00:01:05.670 --> 00:01:08.000
are always older than
the layers at the top.
00:01:08.000 --> 00:01:11.340
Geologists call this rule
the Law of Superposition.
00:01:11.340 --> 00:01:14.140
So if a geologist finds
a fossil of an ammonite
00:01:14.140 --> 00:01:17.250
in a layer of rock above a
fossil of a Dunkleosteus,
00:01:17.250 --> 00:01:19.310
the scientists would know
that the Dunkleosteus
00:01:19.310 --> 00:01:20.750
is older than the ammonite.
00:01:20.750 --> 00:01:23.200
This process is called relative dating
00:01:23.200 --> 00:01:25.470
because it helps scientists
determine the relative ages
00:01:25.470 --> 00:01:27.540
of rock layers and fossils.
00:01:27.540 --> 00:01:30.010
But what does relative ages mean?
00:01:30.010 --> 00:01:31.850
Let's say that I told you my friend Ava
00:01:31.850 --> 00:01:33.130
is younger than her sister,
00:01:33.130 --> 00:01:34.560
but older than her cat.
00:01:34.560 --> 00:01:37.430
Then, I wouldn't be telling
you Ava's exact age,
00:01:37.430 --> 00:01:41.290
but her relative age in relation
to her sister and her cat.
00:01:41.290 --> 00:01:44.010
Let's take a look at another
example of relative ages,
00:01:44.010 --> 00:01:45.630
this time, with rocks.
00:01:45.630 --> 00:01:47.890
Imagine that one day you found a big rock
00:01:47.890 --> 00:01:49.760
with many layers like this.
00:01:49.760 --> 00:01:52.070
Because the rock is a sedimentary rock
00:01:52.070 --> 00:01:54.420
and you remember the Law of Superposition,
00:01:54.420 --> 00:01:56.990
you know that the layers
at the bottom are older
00:01:56.990 --> 00:01:59.940
and you know that the
layers up here are younger.
00:01:59.940 --> 00:02:02.030
But what about this
section of rock right here
00:02:02.030 --> 00:02:04.450
that slices through the other layers?
00:02:04.450 --> 00:02:07.740
Geologists would call this
section an igneous intrusion
00:02:07.740 --> 00:02:10.980
since it was formed for
molten rock that has cooled.
00:02:10.980 --> 00:02:12.980
This particular igneous intrusion
00:02:12.980 --> 00:02:14.300
isn't clearly on top of
00:02:14.300 --> 00:02:16.560
or below any of the
sedimentary rock layers.
00:02:16.560 --> 00:02:19.230
So we can't use the Law
of Superposition here.
00:02:19.230 --> 00:02:21.640
Luckily, geologists have
figured out another rule
00:02:21.640 --> 00:02:24.370
called the law of
crosscutting relationships.
00:02:24.370 --> 00:02:26.650
This rule says that when
two geologic features cross
00:02:26.650 --> 00:02:27.770
or intersect,
00:02:27.770 --> 00:02:30.280
the feature that cuts
through the other is younger,
00:02:30.280 --> 00:02:31.290
and this makes sense
00:02:31.290 --> 00:02:34.120
because you can't break
something before it even exists.
00:02:34.120 --> 00:02:35.640
So since our igneous intrusion
00:02:35.640 --> 00:02:37.710
cuts through the layers
of the sedimentary rock,
00:02:37.710 --> 00:02:40.540
we know that it must be even
younger than the rock layers.
00:02:40.540 --> 00:02:43.360
And what about this
fault or break over here?
00:02:43.360 --> 00:02:45.350
Well, since it slice
through all the layers,
00:02:45.350 --> 00:02:46.880
as well as the igneous rock,
00:02:46.880 --> 00:02:48.810
the law of crosscutting relationships
00:02:48.810 --> 00:02:49.740
tells us that the faults
00:02:49.740 --> 00:02:52.680
must be the very youngest
geologic feature here.
00:02:52.680 --> 00:02:54.840
Other pieces of evidence, like fossils,
00:02:54.840 --> 00:02:56.580
could be used for relative dating.
00:02:56.580 --> 00:02:59.010
For example, suppose a
geologist found a rock
00:02:59.010 --> 00:03:01.410
containing fossils of extinct organisms
00:03:01.410 --> 00:03:04.550
and another rock that contained
fossils of modern organisms.
00:03:04.550 --> 00:03:06.010
The geologist could then deduce
00:03:06.010 --> 00:03:08.820
that the rock with the
extinct organisms is older.
00:03:08.820 --> 00:03:11.810
Certain kinds of fossils,
called index fossils,
00:03:11.810 --> 00:03:13.570
are especially helpful when determining
00:03:13.570 --> 00:03:15.010
the relative age of a rock.
00:03:15.010 --> 00:03:17.230
Index fossils are fossils
that are only found
00:03:17.230 --> 00:03:19.910
on a specific section of
the geologic timescale.
00:03:19.910 --> 00:03:22.690
I always remember what an
index fossil is like this.
00:03:22.690 --> 00:03:24.330
Just like I use my index finger
00:03:24.330 --> 00:03:26.230
to point to give directions,
00:03:26.230 --> 00:03:29.440
index fossils can point to
when on the geologic timescale
00:03:29.440 --> 00:03:30.750
a rock was formed.
00:03:30.750 --> 00:03:33.160
So if a geologist finds
the same index fossil
00:03:33.160 --> 00:03:35.230
in rock layers in two different rocks,
00:03:35.230 --> 00:03:37.150
they know that those rock
layers must have been formed
00:03:37.150 --> 00:03:38.830
around the same time period,
00:03:38.830 --> 00:03:40.450
but fossils aren't the only thing
00:03:40.450 --> 00:03:43.540
that can help geologists figure
out a rock's relative age.
00:03:43.540 --> 00:03:46.200
For example, if a geologist
found two rock layers
00:03:46.200 --> 00:03:48.520
that contained evidence of
the same geologic event,
00:03:48.520 --> 00:03:51.230
like a layer of ash from
a major volcanic eruption,
00:03:51.230 --> 00:03:52.610
the geologists could deduce
00:03:52.610 --> 00:03:54.770
that those rock layers
were made at the same time.
00:03:54.770 --> 00:03:56.710
Relative dating is how
geologists figured out
00:03:56.710 --> 00:03:58.320
that Stegosauruses were extinct
00:03:58.320 --> 00:04:00.720
long before T-Rex's even existed.
00:04:00.720 --> 00:04:02.070
It also helped them figure out
00:04:02.070 --> 00:04:03.670
the first single cellular life
00:04:03.670 --> 00:04:06.270
formed about 3.8 billion years ago
00:04:06.270 --> 00:04:08.080
and the first multicellular life
00:04:08.080 --> 00:04:10.460
formed about 600 million years ago,
00:04:10.460 --> 00:04:13.300
and they figured out that
modern humans didn't even exist
00:04:13.300 --> 00:04:15.360
until about 200,000 years ago,
00:04:15.360 --> 00:04:18.740
which is right at the very end
of the geologic time scale.
00:04:18.740 --> 00:04:21.270
In other words, it took a
really, really long time
00:04:21.270 --> 00:04:23.810
for life to evolve into
what it looks like today.
00:04:23.810 --> 00:04:25.530
We, humans, are very young
00:04:25.530 --> 00:04:27.770
in the grand scheme of
the Earth's history.
00:04:27.770 --> 00:04:29.260
Now, if you'll excuse me,
00:04:29.260 --> 00:04:31.540
I'm gonna go saddle and
ride this Brontosaurus.
00:04:31.540 --> 00:04:33.014
Let's go, ginger snap!
00:04:33.014 --> 00:04:33.847
Hyah!
|
Phases of the moon | https://www.youtube.com/watch?v=f592IgRzq2E | vtt | https://www.youtube.com/api/timedtext?v=f592IgRzq2E&ei=uVWUZbr2F4e3mLAP7bmIsA4&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245289&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=6D668A7420EDBE968D8F0E3427A14B5889AF0B.51A81C0CA85D3EC0ABF2FF59C60A6951678E3136&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.350 --> 00:00:01.740
- [Narrator] Imagine that one day,
00:00:01.740 --> 00:00:04.650
all of the clocks and
computers on Earth broke,
00:00:04.650 --> 00:00:06.840
and all the calendars disappeared.
00:00:06.840 --> 00:00:09.470
How would you keep track of
how much time had passed?
00:00:09.470 --> 00:00:11.680
Well, you could look to the Moon.
00:00:11.680 --> 00:00:13.760
Humans have used the Moon
to keep track of time
00:00:13.760 --> 00:00:15.290
for thousands of years.
00:00:15.290 --> 00:00:17.460
It isn't a coincidence that the word moon
00:00:17.460 --> 00:00:20.020
is related to the word
month in old English.
00:00:20.020 --> 00:00:22.910
The Moon is Earth's
only natural satellite.
00:00:22.910 --> 00:00:25.290
A natural satellite is a
naturally occurring body
00:00:25.290 --> 00:00:26.840
that orbits a planet.
00:00:26.840 --> 00:00:28.490
Some of the planets in our solar system
00:00:28.490 --> 00:00:30.760
have more than 50 satellites or moons,
00:00:30.760 --> 00:00:32.600
but the Earth just has one.
00:00:32.600 --> 00:00:35.150
The Moon does not generate its own light.
00:00:35.150 --> 00:00:36.560
We can see the Moon from the Earth,
00:00:36.560 --> 00:00:39.130
because it is partially lit
by the light from the sun.
00:00:39.130 --> 00:00:41.360
In fact, moonlight is just sunlight
00:00:41.360 --> 00:00:43.360
reflected from the Moon onto Earth.
00:00:43.360 --> 00:00:45.280
The Moon takes about 27 days
00:00:45.280 --> 00:00:47.110
to make a full orbit around Earth.
00:00:47.110 --> 00:00:49.530
And as it does, the lit part of the Moon
00:00:49.530 --> 00:00:51.940
appears to change shape
to us here on Earth.
00:00:51.940 --> 00:00:56.310
These shapes are called the
moon phases, or lunar phases.
00:00:56.310 --> 00:00:58.870
So why do we see different lunar phases?
00:00:58.870 --> 00:01:02.690
Well, the 27 days it takes the
Moon to orbit the Earth once
00:01:02.690 --> 00:01:03.600
is the same amount of time
00:01:03.600 --> 00:01:06.050
it takes the Moon to
rotate on its axis once.
00:01:06.050 --> 00:01:07.680
This means that the same side of the Moon
00:01:07.680 --> 00:01:09.170
is always facing us.
00:01:09.170 --> 00:01:11.210
At the same time, the sun always lights up
00:01:11.210 --> 00:01:12.750
half of the sphere of the Moon.
00:01:12.750 --> 00:01:14.970
However, the side of the
Moon that's facing us
00:01:14.970 --> 00:01:16.590
isn't always the same part of the Moon
00:01:16.590 --> 00:01:17.930
that the sun lights up.
00:01:17.930 --> 00:01:19.928
This causes the Moon to appear
to have different shapes,
00:01:19.928 --> 00:01:21.300
or faces in the sky,
00:01:21.300 --> 00:01:22.870
depending on the time of the month.
00:01:22.870 --> 00:01:25.330
Let's take a closer look
at the Moon's phases.
00:01:25.330 --> 00:01:27.200
First, we have the new moon,
00:01:27.200 --> 00:01:29.360
which happens when the
Moon is closest to the sun
00:01:29.360 --> 00:01:30.330
in its orbit.
00:01:30.330 --> 00:01:32.160
During this phase, the
lit side of the Moon
00:01:32.160 --> 00:01:34.020
is completely facing away from Earth.
00:01:34.020 --> 00:01:36.040
So it looks like the Moon has disappeared.
00:01:36.040 --> 00:01:38.820
In a day or two, we'd be able
to see a little sliver of moon
00:01:38.820 --> 00:01:40.410
in the sky.
00:01:40.410 --> 00:01:41.900
Over the next few days,
00:01:41.900 --> 00:01:44.660
the crescent moon will appear
to get bigger and bigger.
00:01:44.660 --> 00:01:46.050
When the Moon appears to get bigger
00:01:46.050 --> 00:01:48.800
from one day to the next, we
say that the Moon is waxing.
00:01:48.800 --> 00:01:49.780
So this phase of the Moon
00:01:49.780 --> 00:01:52.010
is called the waxing crescent moon.
00:01:52.010 --> 00:01:53.330
You might notice that sometimes
00:01:53.330 --> 00:01:55.680
we can still see the rest
of the Moon in the shadow.
00:01:55.680 --> 00:01:58.450
This is because the Earth
reflects sunlight onto the Moon,
00:01:58.450 --> 00:02:00.570
just like the Moon
reflects light onto Earth.
00:02:00.570 --> 00:02:03.090
Eventually, the Moon appears
to change shape so much
00:02:03.090 --> 00:02:04.710
that it isn't a crescent anymore,
00:02:04.710 --> 00:02:06.700
but a half circle in the sky.
00:02:06.700 --> 00:02:08.990
This is called a first quarter moon.
00:02:08.990 --> 00:02:10.080
There are two ways to think about
00:02:10.080 --> 00:02:12.250
why this phase is called a quarter moon.
00:02:12.250 --> 00:02:14.840
Even though it looks like
the Moon is half illuminated,
00:02:14.840 --> 00:02:16.550
the Moon is a sphere.
00:02:16.550 --> 00:02:19.420
So we can only ever see
half of the Moon from Earth.
00:02:19.420 --> 00:02:20.540
During a quarter moon,
00:02:20.540 --> 00:02:23.460
the Moon forms a right angle
with Earth and the sun.
00:02:23.460 --> 00:02:25.450
This means that we a half lit portion
00:02:25.450 --> 00:02:27.460
of the half of the Moon
that's always facing us.
00:02:27.460 --> 00:02:30.260
It's half of a half, so it's a quarter.
00:02:30.260 --> 00:02:31.950
Also, a first quarter moon
00:02:31.950 --> 00:02:33.950
occurs when the Moon is a
quarter of the way through
00:02:33.950 --> 00:02:35.490
its new cycle.
00:02:35.490 --> 00:02:37.930
Next, there's the waxing gibbous moon.
00:02:37.930 --> 00:02:41.160
The word gibbous comes from the
Latin word meaning humpback.
00:02:41.160 --> 00:02:43.880
Once the Moon is farthest
from the sun in its orbit,
00:02:43.880 --> 00:02:46.350
the full sun lit side
of the Moon faces Earth.
00:02:46.350 --> 00:02:48.610
We call this phase the full moon,
00:02:48.610 --> 00:02:51.000
but the Moon is not done yet.
00:02:51.000 --> 00:02:53.630
It's only finished half of the cycle.
00:02:53.630 --> 00:02:56.470
Next, we have the same
phases, but in reverse.
00:02:56.470 --> 00:02:58.840
As the Moon appears to
get smaller and smaller,
00:02:58.840 --> 00:03:00.520
we say that it's waning.
00:03:00.520 --> 00:03:02.500
The full Moon appears to shrink,
00:03:02.500 --> 00:03:04.900
and then we see a waning gibbous.
00:03:04.900 --> 00:03:06.810
Then there's the third quarter moon.
00:03:06.810 --> 00:03:08.700
This happens when the
Moon is three quarters
00:03:08.700 --> 00:03:09.940
the way done with its cycle,
00:03:09.940 --> 00:03:11.580
and the Moon forms another right angle
00:03:11.580 --> 00:03:12.930
with the sun and the Earth.
00:03:12.930 --> 00:03:15.140
The Moon appears to shrink even more,
00:03:15.140 --> 00:03:17.520
and it becomes a waning crescent,
00:03:17.520 --> 00:03:20.550
and the cycle starts anew
with another new moon.
00:03:20.550 --> 00:03:23.760
Even though the Moon completes
an orbit every 27 days,
00:03:23.760 --> 00:03:27.810
the lunar phases actually
repeat about every 29.5 days.
00:03:27.810 --> 00:03:29.833
This is because the Earth
is revolving around the sun
00:03:29.833 --> 00:03:31.830
while the Moon completes its orbit.
00:03:31.830 --> 00:03:34.960
So the Moon has to travel
a little extra to catch up.
00:03:34.960 --> 00:03:36.570
The Moon isn't just something beautiful
00:03:36.570 --> 00:03:37.740
to look at in the sky,
00:03:37.740 --> 00:03:40.010
or just an easy way to keep track of time.
00:03:40.010 --> 00:03:42.240
The Moon's gravity controls the tides,
00:03:42.240 --> 00:03:44.660
which are the rise and
fall of water in oceans,
00:03:44.660 --> 00:03:46.180
lakes, and rivers.
00:03:46.180 --> 00:03:50.320
Tides allow for unique ecosystems,
like tide pools to exist.
00:03:50.320 --> 00:03:52.400
And we can use the tides
to create electricity,
00:03:52.400 --> 00:03:53.900
and tidal power plants.
00:03:53.900 --> 00:03:56.800
The Moon also helps keep
Earth's access stable.
00:03:56.800 --> 00:03:59.130
Without it, our planet would
wobble more dramatically
00:03:59.130 --> 00:04:01.370
on its axis over long periods of time,
00:04:01.370 --> 00:04:03.950
which would change up our
weather and our seasons.
00:04:03.950 --> 00:04:05.230
So even though your calendar
00:04:05.230 --> 00:04:08.050
is pretty unlikely to
spontaneously combust tomorrow,
00:04:08.050 --> 00:04:09.350
you could still thank the Moon
00:04:09.350 --> 00:04:11.240
for being such a stabilizing influence,
00:04:11.240 --> 00:04:12.953
and good companion to our planet.
|
Potential energy | https://www.youtube.com/watch?v=oGzwVYPxKjg | vtt | https://www.youtube.com/api/timedtext?v=oGzwVYPxKjg&ei=uVWUZeHRGYGNvdIPvPit2A0&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245289&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=D0EE4F600DFE64E8F75DCC13D171571C661EA961.BC26876762EFD8122BB3F3744FDD1E29DF009E78&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.330 --> 00:00:01.410
- [Narrator] Hello, everyone.
00:00:01.410 --> 00:00:03.960
Let's talk about potential energy.
00:00:03.960 --> 00:00:07.090
Potential energy is energy
that is stored in an object,
00:00:07.090 --> 00:00:08.310
and this energy is related
00:00:08.310 --> 00:00:10.780
to the potential or the future possibility
00:00:10.780 --> 00:00:12.890
for an object to have a
different type of energy,
00:00:12.890 --> 00:00:14.900
like kinetic energy for motion,
00:00:14.900 --> 00:00:17.310
that is converted from
that potential energy.
00:00:17.310 --> 00:00:19.060
There are many kinds of potential energy,
00:00:19.060 --> 00:00:21.230
but they all arise from
an object's relation
00:00:21.230 --> 00:00:23.703
to a position, or an original shape.
00:00:25.490 --> 00:00:26.520
So while in general,
00:00:26.520 --> 00:00:28.620
there are many different
types of potential energy,
00:00:28.620 --> 00:00:30.786
there are several specific
types that are very common.
00:00:30.786 --> 00:00:33.200
So, let's talk about these.
00:00:33.200 --> 00:00:34.770
Gravitational potential energy
00:00:34.770 --> 00:00:37.650
is the potential energy
that an object with mass has
00:00:37.650 --> 00:00:40.290
due to the force of gravity
from another object with mass,
00:00:40.290 --> 00:00:42.190
like say, the Earth.
00:00:42.190 --> 00:00:44.350
And in fact, we often use
the surface of the Earth
00:00:44.350 --> 00:00:45.748
to compare an object's position with
00:00:45.748 --> 00:00:47.620
to see how much potential energy it has
00:00:47.620 --> 00:00:50.570
in the Earth's gravitational field.
00:00:50.570 --> 00:00:52.230
Gravity is an attractive force,
00:00:52.230 --> 00:00:53.810
so objects with mass want to move
00:00:53.810 --> 00:00:55.490
towards the surface of the Earth.
00:00:55.490 --> 00:00:57.110
If we move them further away,
00:00:57.110 --> 00:00:59.430
or opposite the direction
of the gravitational force,
00:00:59.430 --> 00:01:02.150
we increase their
gravitational potential energy.
00:01:02.150 --> 00:01:04.593
And the opposite is
true if it gets closer.
00:01:05.910 --> 00:01:07.680
When an object is on the surface of Earth,
00:01:07.680 --> 00:01:09.970
we typically say it has
no potential energy,
00:01:09.970 --> 00:01:12.320
but you could use any
point to be this comparison
00:01:12.320 --> 00:01:15.180
where potential energy is zero.
00:01:15.180 --> 00:01:16.900
Consider a book on a bookshelf.
00:01:16.900 --> 00:01:18.570
If the book is on this shelf,
00:01:18.570 --> 00:01:22.330
we can use this shelf as
the 0.4 potential energy.
00:01:22.330 --> 00:01:23.670
Moving it to a higher shelf
00:01:23.670 --> 00:01:26.070
would mean it has
gravitational potential energy
00:01:26.070 --> 00:01:28.430
relative to that lower shelf,
00:01:28.430 --> 00:01:30.040
or relative to the floor
00:01:30.040 --> 00:01:32.490
if we want to use that as
our comparison instead.
00:01:34.070 --> 00:01:36.500
Next, we have elastic potential energy,
00:01:36.500 --> 00:01:37.780
which is the potential energy
00:01:37.780 --> 00:01:40.790
some objects have due to
their shape being changed.
00:01:40.790 --> 00:01:44.020
These types of objects are
called elastic objects.
00:01:44.020 --> 00:01:46.540
Elastic objects are made
of materials and designed,
00:01:46.540 --> 00:01:49.050
so they have internal or inside forces
00:01:49.050 --> 00:01:52.260
that try to return them
to their original shape.
00:01:52.260 --> 00:01:55.120
One very common example
of this is a spring.
00:01:55.120 --> 00:01:58.310
When you stretch or compress a
spring, you change its shape.
00:01:58.310 --> 00:02:00.420
And the shape of the spring
causes internal forces
00:02:00.420 --> 00:02:04.300
that try to return the
spring to its original shape.
00:02:04.300 --> 00:02:05.797
Now electric potential energy,
00:02:05.797 --> 00:02:08.970
which is the potential
energy a charged object has
00:02:08.970 --> 00:02:12.560
due to the electric force
from another charged object.
00:02:12.560 --> 00:02:15.470
Opposite electric charges
are attracted to one another,
00:02:15.470 --> 00:02:18.210
and similar electric charges are repelled.
00:02:18.210 --> 00:02:19.380
So the potential energy
00:02:19.380 --> 00:02:21.087
depends on what type of charges there are,
00:02:21.087 --> 00:02:23.810
and how far apart they are.
00:02:23.810 --> 00:02:25.500
Potential energy increases
00:02:25.500 --> 00:02:27.192
when the charges move
opposite the direction
00:02:27.192 --> 00:02:28.710
of the electric force,
00:02:28.710 --> 00:02:33.030
for example, when two negative
charges get closer together.
00:02:33.030 --> 00:02:35.250
Similarly, magnetic potential energy
00:02:35.250 --> 00:02:37.920
is the potential energy
a magnetic object has
00:02:37.920 --> 00:02:41.140
due to the magnetic force
from another magnet.
00:02:41.140 --> 00:02:44.210
Magnetic force causes similar
poles to repel one another,
00:02:44.210 --> 00:02:46.290
and opposite poles to attract.
00:02:46.290 --> 00:02:49.180
And because magnets have
north and south poles,
00:02:49.180 --> 00:02:51.110
the potential energy depends not only
00:02:51.110 --> 00:02:52.640
on the position within a field,
00:02:52.640 --> 00:02:55.470
but also the magnets orientation.
00:02:55.470 --> 00:02:57.830
Again, you could increase
the potential energy
00:02:57.830 --> 00:03:00.010
by moving the magnets
opposite the direction
00:03:00.010 --> 00:03:01.250
of the magnetic force.
00:03:01.250 --> 00:03:05.240
For example, by pulling apart
a North Pole and a South Pole.
00:03:05.240 --> 00:03:07.900
All of these types of energy
are due to different forces,
00:03:07.900 --> 00:03:10.400
and are calculated differently
from different equations,
00:03:10.400 --> 00:03:11.830
which we won't cover here,
00:03:11.830 --> 00:03:14.570
but they are all potential energy.
00:03:14.570 --> 00:03:16.550
And these are just a few
of the most common types
00:03:16.550 --> 00:03:18.940
of potential energy, but there are more.
00:03:18.940 --> 00:03:21.470
In summary, potential
energy is the stored energy
00:03:21.470 --> 00:03:23.720
in an object due to its
position, its properties,
00:03:23.720 --> 00:03:25.730
and the forces acting on it.
00:03:25.730 --> 00:03:26.890
Potential energy is measured
00:03:26.890 --> 00:03:29.290
relative to some comparison
position or shape,
00:03:29.290 --> 00:03:32.050
and describes the potential
for other forms of energy,
00:03:32.050 --> 00:03:35.630
commonly kinetic energy
for motion, to exist.
00:03:35.630 --> 00:03:37.610
There are many forms of potential energy,
00:03:37.610 --> 00:03:41.100
including gravitational,
elastic, magnetic, and electric.
00:03:41.100 --> 00:03:41.933
Thanks for watching,
00:03:41.933 --> 00:03:44.053
and I hope you learned a
little bit of something.
|
Worked example: analyzing a generic food web | https://www.youtube.com/watch?v=vniXioPlsLA | vtt | https://www.youtube.com/api/timedtext?v=vniXioPlsLA&ei=vlWUZcHdFda4vdIPoe298Ag&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245294&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=678FE02C86CA5B2CECD0E0786C8E3173CAB330A5.7678EFAE7635D5AE1C8E15360E102CDEAD9E3F4C&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.550 --> 00:00:03.470
- [Narrator] What we have here
is a diagram of a food web
00:00:03.470 --> 00:00:05.650
that shows us how matter and energy
00:00:05.650 --> 00:00:09.420
are transferred between
organisms in an ecosystem.
00:00:09.420 --> 00:00:10.550
But it's a little bit abstract,
00:00:10.550 --> 00:00:12.370
they don't tell us what
these organisms are.
00:00:12.370 --> 00:00:14.310
They just say organism one, organism two,
00:00:14.310 --> 00:00:16.950
organism three, and so forth.
00:00:16.950 --> 00:00:19.680
But even this gives us some information
00:00:19.680 --> 00:00:22.250
about which organism are the producers,
00:00:22.250 --> 00:00:25.120
the primary consumers,
the secondary consumers,
00:00:25.120 --> 00:00:27.310
and the decomposers.
00:00:27.310 --> 00:00:30.240
So the first thing I want
you to think about is
00:00:30.240 --> 00:00:35.020
which arrows show us going from producers,
00:00:35.020 --> 00:00:36.500
I'll write it like,
00:00:36.500 --> 00:00:39.860
to primary consumers?
00:00:39.860 --> 00:00:41.210
Pause the video and think about that.
00:00:41.210 --> 00:00:44.793
Which arrows show producers
to primary consumers?
00:00:46.310 --> 00:00:48.320
All right, now in a food web,
00:00:48.320 --> 00:00:51.070
the giveaway that something is a producer
00:00:51.070 --> 00:00:53.990
is that it doesn't have
arrows coming into it,
00:00:53.990 --> 00:00:56.360
it only has arrows coming out of it.
00:00:56.360 --> 00:01:01.210
And so organism one is a producer.
00:01:01.210 --> 00:01:05.730
Organism five is also a producer.
00:01:05.730 --> 00:01:07.890
Where are they getting their
matter and energy from?
00:01:07.890 --> 00:01:10.330
Well, they're getting their
matter from the environment
00:01:10.330 --> 00:01:13.970
and the energy, in most
cases, is coming from the sun.
00:01:13.970 --> 00:01:16.350
And the things that eat the producers,
00:01:16.350 --> 00:01:18.350
those are primary consumers.
00:01:18.350 --> 00:01:20.720
So this is an arrow that
goes from a producer
00:01:20.720 --> 00:01:22.310
to a primary consumer.
00:01:22.310 --> 00:01:24.520
This is an arrow that goes from a producer
00:01:24.520 --> 00:01:26.100
to a primary consumer.
00:01:26.100 --> 00:01:29.350
And this is an arrow
that goes from a producer
00:01:29.350 --> 00:01:31.840
to a primary consumer.
00:01:31.840 --> 00:01:33.500
Now, with that out of the way,
00:01:33.500 --> 00:01:38.400
which arrows show us going
from a primary consumer
00:01:39.290 --> 00:01:42.900
to a secondary consumer?
00:01:42.900 --> 00:01:45.440
Pause the video and think about that.
00:01:45.440 --> 00:01:47.670
Well, I just said that these things
00:01:47.670 --> 00:01:49.470
that are consuming the producers,
00:01:49.470 --> 00:01:52.930
these are primary, I'll
just say P for primary,
00:01:52.930 --> 00:01:54.580
primary consumer.
00:01:54.580 --> 00:01:57.070
This is a primary consumer.
00:01:57.070 --> 00:02:00.320
This is a primary consumer, as well.
00:02:00.320 --> 00:02:02.350
Now secondary consumers are by definition
00:02:02.350 --> 00:02:04.120
things that aren't decomposers,
00:02:04.120 --> 00:02:06.620
but they're eating primary consumers.
00:02:06.620 --> 00:02:08.710
So they're going to have arrows coming in
00:02:08.710 --> 00:02:11.400
from primary consumers and out
00:02:11.400 --> 00:02:15.040
to either other secondary
consumers or to decomposers.
00:02:15.040 --> 00:02:20.040
So organism three right over
here is a secondary consumer.
00:02:20.540 --> 00:02:22.070
So we're going from a primary consumer
00:02:22.070 --> 00:02:23.140
to a secondary consumer.
00:02:23.140 --> 00:02:25.610
So this arrow is from a primary consumer
00:02:25.610 --> 00:02:27.530
to a secondary consumer.
00:02:27.530 --> 00:02:29.780
This arrow over here is interesting.
00:02:29.780 --> 00:02:32.260
It's a secondary consumer being consumed,
00:02:32.260 --> 00:02:33.790
but you can see that organism four
00:02:33.790 --> 00:02:35.900
only has arrows going into it,
00:02:35.900 --> 00:02:39.070
which is a pretty good clue
that this is a decomposer.
00:02:39.070 --> 00:02:43.003
So I'm not going to call
organism four a secondary,
00:02:43.920 --> 00:02:45.850
a secondary consumer.
00:02:45.850 --> 00:02:47.580
So let's keep going.
00:02:47.580 --> 00:02:50.960
What about the arrow that
goes from organism six
00:02:50.960 --> 00:02:52.110
to organism seven?
00:02:52.110 --> 00:02:55.770
That looks like primary
consumer to primary consumer.
00:02:55.770 --> 00:02:57.060
Well, it turns out that something can be
00:02:57.060 --> 00:03:00.260
both a primary consumer
and a secondary consumer.
00:03:00.260 --> 00:03:03.010
So this is also a secondary consumer.
00:03:03.010 --> 00:03:06.230
Why, because it's eating
a primary consumer
00:03:06.230 --> 00:03:07.830
and it's not a decomposer,
00:03:07.830 --> 00:03:09.470
so this is also another example
00:03:09.470 --> 00:03:11.600
of an arrow from a primary consumer
00:03:11.600 --> 00:03:14.230
to a secondary consumer.
00:03:14.230 --> 00:03:15.770
Last but not least,
00:03:15.770 --> 00:03:19.200
what are the arrows
that go from a consumer,
00:03:19.200 --> 00:03:23.210
that go from a consumer, to a decomposer?
00:03:23.210 --> 00:03:25.330
And we already broke
this down a little bit,
00:03:25.330 --> 00:03:27.340
no pun intended.
00:03:27.340 --> 00:03:29.880
Pause the video and try
to think about that.
00:03:29.880 --> 00:03:32.290
Well, this is the only decomposer
00:03:32.290 --> 00:03:34.050
that's depicted in this diagram,
00:03:34.050 --> 00:03:37.420
and so this is going from
a consumer to a decomposer,
00:03:37.420 --> 00:03:38.600
right over here.
00:03:38.600 --> 00:03:42.570
This is from a consumer to a decomposer,
00:03:42.570 --> 00:03:44.210
and that's all we have here.
00:03:44.210 --> 00:03:46.069
And to be clear, you don't have to go
00:03:46.069 --> 00:03:48.500
only from a consumer to decomposer.
00:03:48.500 --> 00:03:50.500
You could have gone from a producer
00:03:50.500 --> 00:03:51.880
straight to a decomposer.
00:03:51.880 --> 00:03:54.340
You could have arrows that
look like that, as well,
00:03:54.340 --> 00:03:58.330
because if a plant dies
and it gets decomposed,
00:03:58.330 --> 00:04:00.270
well, it's going to be,
that matter and energy
00:04:00.270 --> 00:04:02.523
is going to be used by that decomposer.
|
Worked example: analyzing an ocean food web | https://www.youtube.com/watch?v=vGwhsG-4j-0 | vtt | https://www.youtube.com/api/timedtext?v=vGwhsG-4j-0&ei=vlWUZYqDHZnUxN8P7LqKEA&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245294&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=3EE9C66C138E5068671E8C96122FE6428568FCA8.200F7E2C94C84829BC6139209A82AF9269FB8B1E&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.350 --> 00:00:01.950
- [Instructor] So this
diagram right over here
00:00:01.950 --> 00:00:03.410
describes a food web.
00:00:03.410 --> 00:00:04.930
And a food web models
00:00:04.930 --> 00:00:07.910
how energy and matter
moves in an ecosystem.
00:00:07.910 --> 00:00:10.340
And we're going to use this food web
00:00:10.340 --> 00:00:11.690
to answer some questions,
00:00:11.690 --> 00:00:14.400
to make sure we understand food webs.
00:00:14.400 --> 00:00:16.780
So the first thing I'm
going to ask you is,
00:00:16.780 --> 00:00:21.000
what are the producers in this food web.
00:00:21.000 --> 00:00:25.433
Pause this video and see
if you can figure this out.
00:00:26.610 --> 00:00:28.830
All right, now let's work
through this together.
00:00:28.830 --> 00:00:30.780
The producers are the ones
00:00:30.780 --> 00:00:33.950
that can take matter in the
ecosystem, in the environment,
00:00:33.950 --> 00:00:36.890
and energy from an outside
source, usually the sun,
00:00:36.890 --> 00:00:39.470
in order to construct themselves
00:00:39.470 --> 00:00:42.290
and also in order to store that energy.
00:00:42.290 --> 00:00:44.210
And when you look at a food web,
00:00:44.210 --> 00:00:47.740
producers are going to have
arrows pointed away from them.
00:00:47.740 --> 00:00:49.730
So they're getting their energy
00:00:49.730 --> 00:00:51.400
and their matter from the environment
00:00:51.400 --> 00:00:53.710
and then other people are
going to consume them.
00:00:53.710 --> 00:00:55.940
And we're gonna talk about
them in a little bit.
00:00:55.940 --> 00:00:59.960
But we can see here that
the kelp is a producer.
00:00:59.960 --> 00:01:02.820
This is an aquatic ecosystem
that we're looking at.
00:01:02.820 --> 00:01:04.270
But the kelp is a producer.
00:01:04.270 --> 00:01:06.290
There's no arrows going into it
00:01:06.290 --> 00:01:09.960
so it's using the sun and
elements and atoms and molecules
00:01:09.960 --> 00:01:12.440
that it's finding in its
environment in order to grow.
00:01:12.440 --> 00:01:16.030
And we can also see that's the
case with the phytoplankton.
00:01:16.030 --> 00:01:19.150
It's also able to do
photosynthesis, like the kelp,
00:01:19.150 --> 00:01:21.623
and capture that energy from the sun.
00:01:22.610 --> 00:01:27.610
Now, the next question I have
is, where are the decomposers?
00:01:28.480 --> 00:01:31.653
Pause the video and
try to answer that one.
00:01:32.970 --> 00:01:33.830
All right.
00:01:33.830 --> 00:01:36.150
Now you might remember decomposers,
00:01:36.150 --> 00:01:38.260
you can think about that's where a lot
00:01:38.260 --> 00:01:40.240
of the energy and the matter ends up,
00:01:40.240 --> 00:01:42.950
to be decomposed and then recycled again
00:01:42.950 --> 00:01:45.190
and be reused again by the producers.
00:01:45.190 --> 00:01:47.110
And if you're looking at a food web,
00:01:47.110 --> 00:01:48.210
these would-be organisms
00:01:48.210 --> 00:01:50.190
where all of the arrows point to them,
00:01:50.190 --> 00:01:52.750
but you don't have any
arrows coming from them.
00:01:52.750 --> 00:01:55.650
And over here, it's
clear that the bacteria,
00:01:55.650 --> 00:01:58.190
and there's many different
species of bacteria
00:01:58.190 --> 00:02:00.100
or many different types of bacteria,
00:02:00.100 --> 00:02:03.970
but the bacteria here are the decomposers.
00:02:03.970 --> 00:02:05.740
Next, I am going to ask you
00:02:05.740 --> 00:02:08.747
about the primary consumers.
00:02:11.410 --> 00:02:14.363
Pause this video and see
if you can identify them.
00:02:16.930 --> 00:02:19.700
Well, primary consumers are consumers
00:02:19.700 --> 00:02:22.370
that directly eat the producers.
00:02:22.370 --> 00:02:24.920
And so let's see, who is eating the kelp?
00:02:24.920 --> 00:02:27.530
You have have the sea
urchin eating the kelp.
00:02:27.530 --> 00:02:29.890
You have the fish eating the kelp.
00:02:29.890 --> 00:02:31.600
Who's eating the phytoplankton?
00:02:31.600 --> 00:02:35.360
You have the zooplankton
eating the phytoplankton.
00:02:35.360 --> 00:02:39.040
So these are primary consumers.
00:02:39.040 --> 00:02:42.780
Next, let's think about
secondary consumers.
00:02:42.780 --> 00:02:44.033
Secondary.
00:02:45.180 --> 00:02:49.230
These are those that
eat primary consumers.
00:02:49.230 --> 00:02:51.520
Pause the video and think about that.
00:02:51.520 --> 00:02:52.370
Well, let's think about
00:02:52.370 --> 00:02:55.060
who's eating these primary consumers.
00:02:55.060 --> 00:02:57.820
You have the otter.
00:02:57.820 --> 00:03:00.570
What's interesting is the
fish is a primary consumer
00:03:00.570 --> 00:03:03.200
because it consumes kelp,
which is a producer,
00:03:03.200 --> 00:03:06.610
but it also can consume
another primary consumer.
00:03:06.610 --> 00:03:08.700
So, a fish, or the fish here,
00:03:08.700 --> 00:03:11.860
are both primary and secondary consumers.
00:03:11.860 --> 00:03:14.330
And then I think we are done.
00:03:14.330 --> 00:03:16.820
So you can see the general notions here.
00:03:16.820 --> 00:03:19.270
The producers have arrows
going away from them
00:03:19.270 --> 00:03:20.640
but no arrows coming into them
00:03:20.640 --> 00:03:22.840
because they're getting
their energy from the sun
00:03:22.840 --> 00:03:25.580
and they're using the
matter in the ecosystem.
00:03:25.580 --> 00:03:29.330
Primary consumers are
eating those producers,
00:03:29.330 --> 00:03:30.970
and you can see they have
arrows going into them.
00:03:30.970 --> 00:03:34.760
And then they're eaten by other
folks, secondary consumers,
00:03:34.760 --> 00:03:36.800
or those that eat the primary consumers.
00:03:36.800 --> 00:03:39.430
And then last but not least,
you have the bacteria,
00:03:39.430 --> 00:03:43.230
which are decomposers, where
the arrows all point to them
00:03:43.230 --> 00:03:44.810
and they continue to use that energy
00:03:44.810 --> 00:03:47.860
and then they take those
nutrients, those molecules,
00:03:47.860 --> 00:03:49.790
and they put 'em back into the ecosystem
00:03:49.790 --> 00:03:51.633
so that it can be recycled again.
|
Matter and energy in food webs | https://www.youtube.com/watch?v=qIgL05zOx5U | vtt | https://www.youtube.com/api/timedtext?v=qIgL05zOx5U&ei=vlWUZaO-KLiBhcIPxNOJ-AY&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245294&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=A67D8538289612BE0D9D6561DDD6FB2012C4DFFD.27BA1AE68F3F41CEA5445AD59B489CA3541A43ED&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.840 --> 00:00:01.673
- [Narrator] In this video,
00:00:01.673 --> 00:00:03.160
we're gonna talk about food webs,
00:00:03.160 --> 00:00:04.760
which is really just a way
00:00:04.760 --> 00:00:07.600
of picturing how all of the matter,
00:00:07.600 --> 00:00:12.600
and how all of the energy
flows inside of an ecosystem.
00:00:12.690 --> 00:00:14.050
Now, when I talk about matter,
00:00:14.050 --> 00:00:16.730
I'm talking about the
atoms in an ecosystem,
00:00:16.730 --> 00:00:18.830
the molecules, when you look at your hand,
00:00:18.830 --> 00:00:20.750
it is made up of atoms.
00:00:20.750 --> 00:00:22.350
And it turns out that the matter
00:00:22.350 --> 00:00:24.400
is not created or destroyed,
00:00:24.400 --> 00:00:27.510
it's just recycled
throughout an ecosystem.
00:00:27.510 --> 00:00:29.460
And we're going to see that in a second.
00:00:29.460 --> 00:00:31.083
And then when we talk about energy,
00:00:31.083 --> 00:00:33.549
it's the energy that your
cells need to be alive,
00:00:33.549 --> 00:00:37.440
the energy you need to be
alive, to not just exist,
00:00:37.440 --> 00:00:40.340
but to do things, to think, to move.
00:00:40.340 --> 00:00:43.690
And so this food web
essentially describes that.
00:00:43.690 --> 00:00:45.620
As we've talked about in other videos,
00:00:45.620 --> 00:00:50.130
in most ecosystems, the
great majority of the energy
00:00:50.130 --> 00:00:53.630
in an ecosystem comes from the sun.
00:00:53.630 --> 00:00:56.690
So what we have here is
the sun produces energy.
00:00:56.690 --> 00:00:58.880
It travels to Earth,
00:00:58.880 --> 00:01:03.410
and then you have organisms,
which we would call producers,
00:01:03.410 --> 00:01:07.230
that are able to take that
light energy from the sun,
00:01:07.230 --> 00:01:11.060
and then take atoms and
molecules from its environment,
00:01:11.060 --> 00:01:14.240
things like carbon dioxide in the air,
00:01:14.240 --> 00:01:17.090
things like water, and other nutrients.
00:01:17.090 --> 00:01:19.480
And it's able to construct itself
00:01:19.480 --> 00:01:21.670
using that energy from the sun.
00:01:21.670 --> 00:01:23.300
Now, when it constructs itself,
00:01:23.300 --> 00:01:25.370
it not only gives it structure,
00:01:25.370 --> 00:01:27.610
but it's also able to store energy.
00:01:27.610 --> 00:01:30.610
And right over here, we have
several producers depicted.
00:01:30.610 --> 00:01:33.760
We have this tree here, which
is able to do photosynthesis.
00:01:33.760 --> 00:01:36.600
We have the grass here that's
able to do photosynthesis,
00:01:36.600 --> 00:01:38.020
and it's not just plants.
00:01:38.020 --> 00:01:39.250
You have things like algae,
00:01:39.250 --> 00:01:43.050
and other microorganisms that
are able to be producers.
00:01:43.050 --> 00:01:45.030
But then we have things like this bunny,
00:01:45.030 --> 00:01:48.090
and this bunny is not
able to harness energy
00:01:48.090 --> 00:01:50.140
from the sun by itself.
00:01:50.140 --> 00:01:53.780
In order for it to get
its energy and its matter,
00:01:53.780 --> 00:01:56.220
it needs to eat one of these producers,
00:01:56.220 --> 00:01:58.370
probably some of this grass.
00:01:58.370 --> 00:02:01.330
And so we would call this
bunny right over here,
00:02:01.330 --> 00:02:04.680
this rabbit, we would call it a consumer.
00:02:04.680 --> 00:02:05.810
And it is a consumer,
00:02:05.810 --> 00:02:08.840
you could think of it as
both matter and energy.
00:02:08.840 --> 00:02:10.630
When it eats that plant,
00:02:10.630 --> 00:02:13.840
those atoms are then able
to make up the bunny.
00:02:13.840 --> 00:02:15.114
It will poop out a little bit,
00:02:15.114 --> 00:02:18.360
so some of the matter might
end up right over here.
00:02:18.360 --> 00:02:20.610
But then also there is energy
00:02:20.610 --> 00:02:22.650
that is stored in those molecules,
00:02:22.650 --> 00:02:25.860
and that rabbit can use that
energy to exist and live,
00:02:25.860 --> 00:02:27.150
but as it does it,
00:02:27.150 --> 00:02:31.433
it does release some of the
energy in the form of heat.
00:02:32.320 --> 00:02:34.890
And actually, even
producers need to use energy
00:02:34.890 --> 00:02:35.723
in order to live.
00:02:35.723 --> 00:02:39.430
And as they do that,
they also release heat.
00:02:39.430 --> 00:02:42.770
Now we have this fox, the
fox is not a vegetarian.
00:02:42.770 --> 00:02:45.700
It does not eat, it does not eat trees.
00:02:45.700 --> 00:02:48.410
It likes to eat things
like squirrels and bunnies,
00:02:48.410 --> 00:02:50.710
but big picture, it's not
producing its own food.
00:02:50.710 --> 00:02:54.210
It's consuming food, so
it also is a consumer.
00:02:54.210 --> 00:02:56.250
We can differentiate more in the future
00:02:56.250 --> 00:02:58.140
between things that eat plants,
00:02:58.140 --> 00:03:00.220
and things that eat other animals.
00:03:00.220 --> 00:03:01.440
And you can see in this food web,
00:03:01.440 --> 00:03:04.714
we draw an arrow from the
thing that is being consumed
00:03:04.714 --> 00:03:07.090
to the thing that is doing the consuming.
00:03:07.090 --> 00:03:09.620
So a rabbit consumes a plant,
00:03:09.620 --> 00:03:12.660
and so the arrow goes from
the plant to the rabbit.
00:03:12.660 --> 00:03:15.380
A fox consumes a rabbit or a squirrel,
00:03:15.380 --> 00:03:19.080
so an arrow goes from the rabbit
or the squirrel to the fox.
00:03:19.080 --> 00:03:20.290
Now some of you might have noticed
00:03:20.290 --> 00:03:22.910
that we have these arrows
that are pointing downward.
00:03:22.910 --> 00:03:25.040
And so let me scroll down a little bit.
00:03:25.040 --> 00:03:28.400
And we see these
microorganisms, the worms,
00:03:28.400 --> 00:03:30.940
the fungi, the mushrooms right over here,
00:03:30.940 --> 00:03:34.070
and we call these decomposers.
00:03:34.070 --> 00:03:37.000
Now what decomposers are really doing
00:03:37.000 --> 00:03:38.380
is what what you would imagine,
00:03:38.380 --> 00:03:41.330
breaking down all of the
things that might die,
00:03:41.330 --> 00:03:43.300
the poop that is falling down.
00:03:43.300 --> 00:03:47.600
And by doing that, it's
continuing to recycle that matter.
00:03:47.600 --> 00:03:48.880
And when it decomposes,
00:03:48.880 --> 00:03:51.340
those atoms are released
back into the soil,
00:03:51.340 --> 00:03:52.670
or the atmosphere,
00:03:52.670 --> 00:03:55.460
and then that can be
reused by the producers.
00:03:55.460 --> 00:03:58.420
And once again, every
organism in this food web
00:03:58.420 --> 00:04:00.990
is using some of the
energy in order to exist,
00:04:00.990 --> 00:04:03.330
and do whatever it needs to do.
00:04:03.330 --> 00:04:05.900
And some of that energy is being released
00:04:05.900 --> 00:04:09.573
as heat in every single situation.
|
Photosynthesis in ecosystems | https://www.youtube.com/watch?v=_1U6uMmUJZU | vtt | https://www.youtube.com/api/timedtext?v=_1U6uMmUJZU&ei=vlWUZai8KIachcIPoquZiAg&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245294&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=7C556A9592EFECFD08C86142C2669981A843BFE7.70F15DA164015A4FA9630C377922C9153597F289&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.400 --> 00:00:01.233
- [Instructor] When you look at
00:00:01.233 --> 00:00:03.400
a rainforest ecosystem like this,
00:00:03.400 --> 00:00:05.660
one of the obvious questions may be,
00:00:05.660 --> 00:00:07.300
where do these plants come from?
00:00:07.300 --> 00:00:08.150
How do they grow?
00:00:08.150 --> 00:00:09.370
They're growing all the time,
00:00:09.370 --> 00:00:11.070
they're getting larger
and larger and larger.
00:00:11.070 --> 00:00:13.990
Where does that mass, where
does that matter come from?
00:00:13.990 --> 00:00:15.890
Pause this video and think about that.
00:00:17.120 --> 00:00:19.960
Well, you might already be
guessing where it comes from.
00:00:19.960 --> 00:00:22.390
It might have something
to do with photosynthesis,
00:00:22.390 --> 00:00:25.760
which we go into a lot
of depth in other videos,
00:00:25.760 --> 00:00:30.210
but this is a process where
you have carbon dioxide
00:00:30.210 --> 00:00:33.990
from the air in conjunction with water
00:00:33.990 --> 00:00:37.190
that primarily is coming from the soil,
00:00:37.190 --> 00:00:40.600
and it uses energy from the sun
00:00:40.600 --> 00:00:42.100
so I'll just draw that in,
00:00:42.100 --> 00:00:44.380
these yellow squiggles
coming from the sun,
00:00:44.380 --> 00:00:46.290
in order to do two things.
00:00:46.290 --> 00:00:48.180
The plant is going to be building itself
00:00:48.180 --> 00:00:51.090
using the matter in the
carbon dioxide and the water
00:00:51.090 --> 00:00:54.760
while also expelling
oxygen as a byproduct.
00:00:54.760 --> 00:00:56.760
And this matter that the plant is able
00:00:56.760 --> 00:00:59.450
to take from its environment
with photosynthesis
00:00:59.450 --> 00:01:02.220
is used to both become
the structure of the plant
00:01:02.220 --> 00:01:05.590
and a store of energy
in the form of sugars.
00:01:05.590 --> 00:01:07.440
Now, animals like you and me,
00:01:07.440 --> 00:01:10.700
we get our energy by
then eating these plants.
00:01:10.700 --> 00:01:12.590
And how do we unlock that energy?
00:01:12.590 --> 00:01:15.410
Well, that's where this
oxygen is really useful.
00:01:15.410 --> 00:01:16.900
That's why we need to breathe oxygen
00:01:16.900 --> 00:01:18.790
because by breathing the oxygen,
00:01:18.790 --> 00:01:21.780
we can essentially do
photosynthesis in reverse,
00:01:21.780 --> 00:01:24.240
and we can break down this matter,
00:01:24.240 --> 00:01:27.000
these sugars, that we're
getting from plants.
00:01:27.000 --> 00:01:29.050
So all of this biomass is coming
00:01:29.050 --> 00:01:31.400
from essentially water from the soil
00:01:31.400 --> 00:01:34.160
and carbon dioxide,
and energy from the sun
00:01:34.160 --> 00:01:36.720
is used essentially put it together.
00:01:36.720 --> 00:01:38.190
There might be a few other nutrients
00:01:38.190 --> 00:01:40.980
that are also coming from the
environment, like the soil,
00:01:40.980 --> 00:01:43.553
but primarily the water
and the carbon dioxide.
|
Analog vs. digital signals | https://www.youtube.com/watch?v=PEYdn56pdcQ | vtt | https://www.youtube.com/api/timedtext?v=PEYdn56pdcQ&ei=v1WUZZLhNqq9mLAPgaWr8Ak&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245295&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=BF6813DFCD18051D6D276D0665801753EADD6BF5.D538FC16052EE2C36DDBE6118F013A7FE49A30FA&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.140 --> 00:00:01.240
- [Narrator] In this
video we're gonna think
00:00:01.240 --> 00:00:04.690
about analog versus digital signals.
00:00:04.690 --> 00:00:06.830
And one way to think about the difference
00:00:06.830 --> 00:00:10.810
is an analog signal is trying to reproduce
00:00:10.810 --> 00:00:13.330
exactly in some type of a signal
00:00:13.330 --> 00:00:17.130
what is going on while a
digital signal is converting it,
00:00:17.130 --> 00:00:20.950
usually the ones and zeros which
then can be converted back.
00:00:20.950 --> 00:00:22.480
So the first thing to realize
00:00:22.480 --> 00:00:24.980
is that almost any type of information,
00:00:24.980 --> 00:00:27.840
it might be how intense a certain color is
00:00:27.840 --> 00:00:31.690
or how bright it is or it
might be a frequency of sound,
00:00:31.690 --> 00:00:34.830
all of that can be represented as numbers.
00:00:34.830 --> 00:00:36.190
So whether you're trying to transmit
00:00:36.190 --> 00:00:38.380
an analog signal or a digital signal
00:00:38.380 --> 00:00:41.530
it really is about how do
you communicate numbers
00:00:41.530 --> 00:00:43.550
using some type of signal.
00:00:43.550 --> 00:00:46.360
And as an example, let's
say that you are trying
00:00:46.360 --> 00:00:50.360
to communicate the number 24 to someone.
00:00:50.360 --> 00:00:53.643
Well, one way to do it
is as an analog signal.
00:00:55.120 --> 00:00:57.350
You could have, as time goes on,
00:00:57.350 --> 00:01:00.460
maybe this is some type
of voltage across a wire.
00:01:00.460 --> 00:01:01.930
And if you put that voltage
00:01:01.930 --> 00:01:03.500
right at what the other person
00:01:03.500 --> 00:01:07.190
receiving it could interpret it as 24,
00:01:07.190 --> 00:01:09.630
well then you would
transmit it and they might,
00:01:09.630 --> 00:01:14.290
if they get this nice clean
signal, see it as a 24.
00:01:14.290 --> 00:01:16.450
Now the problem with analog signals
00:01:16.450 --> 00:01:19.280
is what happens when
you have interference.
00:01:19.280 --> 00:01:21.770
So let's say this is a really long wire
00:01:21.770 --> 00:01:23.180
that you're transmitting it over
00:01:23.180 --> 00:01:26.170
or you're transmitting
it using radio waves,
00:01:26.170 --> 00:01:27.540
and there's a lot of bad weather
00:01:27.540 --> 00:01:29.110
or other types of interference.
00:01:29.110 --> 00:01:32.720
And so on the receiving end
even though you transmit
00:01:32.720 --> 00:01:36.280
something that looks like
this, that is a clear 24,
00:01:36.280 --> 00:01:38.740
the other person might
get something like this.
00:01:38.740 --> 00:01:42.190
And so this isn't obvious
that is a 24 anymore.
00:01:42.190 --> 00:01:44.610
It goes between 20 and 30,
00:01:44.610 --> 00:01:47.380
and this could be interpreted as static
00:01:47.380 --> 00:01:48.860
or a garbled up message
00:01:48.860 --> 00:01:50.570
or just doesn't sound as clean
00:01:50.570 --> 00:01:52.910
depending on what the 24
is trying to represent,
00:01:52.910 --> 00:01:54.510
or the image isn't as clear,
00:01:54.510 --> 00:01:57.690
if this is representing say the lightness
00:01:57.690 --> 00:02:00.010
or the brightness of a pixel.
00:02:00.010 --> 00:02:05.010
Now the other option is to
convert that 24 into binary.
00:02:06.080 --> 00:02:11.080
So 24 can be represented
in binary as 1 1 0 0 0.
00:02:13.160 --> 00:02:15.260
Now we have other videos on Khan Academy
00:02:15.260 --> 00:02:17.480
that explain how to convert back and forth
00:02:17.480 --> 00:02:20.830
between our decimal
system that has 10 digits,
00:02:20.830 --> 00:02:23.820
zero through nine, and the binary system,
00:02:23.820 --> 00:02:26.310
which has two digits, zero and one.
00:02:26.310 --> 00:02:27.310
But in case you're curious,
00:02:27.310 --> 00:02:28.720
and you don't have to understand this
00:02:28.720 --> 00:02:30.910
to know the difference between
analog and digital signals
00:02:30.910 --> 00:02:32.410
and when they might be useful,
00:02:32.410 --> 00:02:35.150
this first place is the ones
place just as you're used to.
00:02:35.150 --> 00:02:37.020
But instead of this being the tens place,
00:02:37.020 --> 00:02:38.560
this is the twos place.
00:02:38.560 --> 00:02:40.150
Instead of this being the hundreds place,
00:02:40.150 --> 00:02:41.910
this is the forth place.
00:02:41.910 --> 00:02:44.530
Instead of this being the thousands place,
00:02:44.530 --> 00:02:46.300
this is the eights place.
00:02:46.300 --> 00:02:49.540
And instead of that being
the ten thousandths place,
00:02:49.540 --> 00:02:51.550
that's the sixteens place.
00:02:51.550 --> 00:02:52.750
So one way to think about it,
00:02:52.750 --> 00:02:57.360
1 1 0 0 0 means 1/16 and 1/8.
00:02:57.360 --> 00:03:00.240
And if you add those
together, you would get 24.
00:03:00.240 --> 00:03:02.633
What would that actually
look like as a signal?
00:03:03.480 --> 00:03:05.640
Well, it could look something like this.
00:03:05.640 --> 00:03:07.450
Where the person interpreting it knows
00:03:07.450 --> 00:03:09.220
that over this first time period
00:03:09.220 --> 00:03:10.560
whatever voltage you're getting,
00:03:10.560 --> 00:03:12.350
that tells you your first digit,
00:03:12.350 --> 00:03:13.980
that over the next time, period
00:03:13.980 --> 00:03:16.420
whatever voltage you're getting
tells you the second digit,
00:03:16.420 --> 00:03:18.090
and so on and so forth.
00:03:18.090 --> 00:03:22.540
So this would be 1 1 0 0 0.
00:03:22.540 --> 00:03:24.130
Now, why is this useful?
00:03:24.130 --> 00:03:25.620
Well, let's think about the situation
00:03:25.620 --> 00:03:28.750
where all of a sudden
there's interference again.
00:03:28.750 --> 00:03:30.040
Now with the interference,
00:03:30.040 --> 00:03:35.040
you could still interpret
this exactly as 1 1 0 0 0.
00:03:35.190 --> 00:03:37.080
Remember the person receiving the signal
00:03:37.080 --> 00:03:38.760
or the system receiving the signal
00:03:38.760 --> 00:03:39.850
is just trying to determine
00:03:39.850 --> 00:03:41.530
whether it's getting a one or a zero.
00:03:41.530 --> 00:03:44.800
So even though this is being
perturbed right over here,
00:03:44.800 --> 00:03:46.750
it's clear that we are at a one.
00:03:46.750 --> 00:03:49.750
We know that it would not be a 0.9 or 1.1.
00:03:49.750 --> 00:03:52.040
It has to be either one or zero.
00:03:52.040 --> 00:03:55.890
So it's clear that over
this part right over here,
00:03:55.890 --> 00:03:57.100
you're getting a one,
00:03:57.100 --> 00:03:59.550
and then over here you're
getting three zero.
00:03:59.550 --> 00:04:03.620
So they would be able to
interpret it as 1 1 0 0 0,
00:04:03.620 --> 00:04:06.153
which is once again exactly 24.
|
Absorption and reflection | https://www.youtube.com/watch?v=6uHk1Q-Qb8k | vtt | https://www.youtube.com/api/timedtext?v=6uHk1Q-Qb8k&ei=vlWUZeqeO5yUvdIPwMmimAE&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245295&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=1874F7E06FD54BF61ED3E66DBBFCF9D393AD8C0E.D682FE9D1A04DEA9012C23BF74519FC77766D36C&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.270 --> 00:00:02.060
- [Instructor] I'm showing
you this beautiful picture
00:00:02.060 --> 00:00:05.490
of snow-capped mountains
overlooking this Alpine Lake,
00:00:05.490 --> 00:00:08.360
because there's a lot
of light moving around.
00:00:08.360 --> 00:00:10.130
Now, we're gonna talk
about the different ways
00:00:10.130 --> 00:00:13.890
that light can interact
with different media,
00:00:13.890 --> 00:00:17.480
but what I'm talking about can
generally be true of waves.
00:00:17.480 --> 00:00:19.160
But focusing on light for a second,
00:00:19.160 --> 00:00:20.420
we've already talked about how,
00:00:20.420 --> 00:00:22.130
if we go from one medium to another,
00:00:22.130 --> 00:00:24.670
if we're transmitting from
one medium to another,
00:00:24.670 --> 00:00:27.590
that the light can go through a medium.
00:00:27.590 --> 00:00:30.580
And as it goes to that boundary
from one medium to another,
00:00:30.580 --> 00:00:32.140
its direction can change.
00:00:32.140 --> 00:00:34.060
And we talk about that in another video,
00:00:34.060 --> 00:00:36.020
and we call that refraction.
00:00:36.020 --> 00:00:38.090
We have refraction when
we enter the material,
00:00:38.090 --> 00:00:40.790
and then we have more
refraction when we get out.
00:00:40.790 --> 00:00:43.700
Now, there's other things
that light can also do,
00:00:43.700 --> 00:00:46.060
and that's the focus of this video,
00:00:46.060 --> 00:00:48.570
reflection and absorption.
00:00:48.570 --> 00:00:49.800
Now you probably have a sense
00:00:49.800 --> 00:00:51.550
of what happens with reflection.
00:00:51.550 --> 00:00:54.080
We can see a reflection of the mountains
00:00:54.080 --> 00:00:55.600
in the lake right over here.
00:00:55.600 --> 00:00:57.990
And the reason why we
can see the reflection
00:00:57.990 --> 00:00:59.540
of the mountains and the lake here
00:00:59.540 --> 00:01:03.070
is because light that is
coming from this mountain
00:01:03.070 --> 00:01:07.670
is hitting the lake and then
it is bouncing off of it,
00:01:07.670 --> 00:01:11.830
and then coming to an observer's
eyeball right over here,
00:01:11.830 --> 00:01:15.180
and so they see the light
that's coming from here,
00:01:15.180 --> 00:01:17.180
they see it as coming from over here,
00:01:17.180 --> 00:01:18.520
because it is bounced off.
00:01:18.520 --> 00:01:22.160
And so reflection is exactly
that, light is coming in,
00:01:22.160 --> 00:01:24.210
it hits that other material,
00:01:24.210 --> 00:01:27.300
and then if it bounces
off, that's reflection.
00:01:27.300 --> 00:01:30.320
Now, the other thing that
light can do is get absorbed.
00:01:30.320 --> 00:01:33.610
Absorbed is when the
material doesn't reflect any,
00:01:33.610 --> 00:01:35.340
it doesn't transmit any through it,
00:01:35.340 --> 00:01:37.020
if it's completely absorbing.
00:01:37.020 --> 00:01:40.070
And so that would be
a situation like this.
00:01:40.070 --> 00:01:41.740
Now, the reality in the real world
00:01:41.740 --> 00:01:43.830
is we have oftentimes a little bit
00:01:43.830 --> 00:01:46.170
of all of the above happening.
00:01:46.170 --> 00:01:50.800
For example, when we look
at this white snow up here,
00:01:50.800 --> 00:01:52.730
this is reflecting pretty well.
00:01:52.730 --> 00:01:55.150
So there's light that's
coming from the sun,
00:01:55.150 --> 00:01:57.420
or maybe it's being
reflected off of the clouds,
00:01:57.420 --> 00:01:59.030
or maybe it's getting through the clouds,
00:01:59.030 --> 00:02:02.320
and when it hits that
snow, it gets reflected.
00:02:02.320 --> 00:02:03.950
Now, the reason why we
don't see a reflection
00:02:03.950 --> 00:02:06.370
the way that we see in
this lake right over here
00:02:06.370 --> 00:02:09.370
is the snow reflects it in
all different directions,
00:02:09.370 --> 00:02:11.310
but the fact that it's
that bright color, in fact,
00:02:11.310 --> 00:02:13.260
you might need sunglasses
to look at the snow,
00:02:13.260 --> 00:02:15.270
just as much as you
need to look at the sky,
00:02:15.270 --> 00:02:18.000
is that it's reflecting most of the light.
00:02:18.000 --> 00:02:20.690
But if you go down here
where we see the trees,
00:02:20.690 --> 00:02:23.070
the same light from the sky is hitting it,
00:02:23.070 --> 00:02:25.840
but not as much light is
coming back to our eye,
00:02:25.840 --> 00:02:28.530
and that's because this
part of the mountain,
00:02:28.530 --> 00:02:31.260
it might be trees, it might
be rock, it might be dirt,
00:02:31.260 --> 00:02:34.040
is absorbing more of the light,
00:02:34.040 --> 00:02:35.330
but it's still reflecting some.
00:02:35.330 --> 00:02:36.890
We can still see it a little bit.
00:02:36.890 --> 00:02:39.860
So this might be where most
of it is getting absorbed,
00:02:39.860 --> 00:02:42.610
but a little bit of the
light gets reflected,
00:02:42.610 --> 00:02:44.670
which we can see right over there.
00:02:44.670 --> 00:02:46.970
And if we think about the
water right over here,
00:02:46.970 --> 00:02:49.160
some of the light is
probably making it through
00:02:49.160 --> 00:02:51.720
and probably refracting as it does so.
00:02:51.720 --> 00:02:53.570
Some of it is getting absorbed
00:02:53.570 --> 00:02:55.210
as it makes its way through the water.
00:02:55.210 --> 00:02:56.470
If this was a really deep lake,
00:02:56.470 --> 00:02:58.770
when you get to the bottom,
it could be very, very dark.
00:02:58.770 --> 00:03:00.180
And then, as we talked about,
00:03:00.180 --> 00:03:02.000
it looks like a good bit is reflecting.
00:03:02.000 --> 00:03:03.900
When we look at the image
that we see in the lake,
00:03:03.900 --> 00:03:07.290
it looks almost as
bright as the real thing.
00:03:07.290 --> 00:03:10.830
So as I said, this is
happening all around you.
00:03:10.830 --> 00:03:13.380
In fact, when people make
fancy computer graphics,
00:03:13.380 --> 00:03:16.190
they actually try to do
exactly what the light would do
00:03:16.190 --> 00:03:19.590
in the real world to make
an image for your eyes
00:03:19.590 --> 00:03:21.490
that look like the real world.
00:03:21.490 --> 00:03:23.150
And they're thinking exactly about this.
00:03:23.150 --> 00:03:24.960
How much gets through the substance?
00:03:24.960 --> 00:03:27.700
How much gets reflected,
and how much gets absorbed?
00:03:27.700 --> 00:03:28.820
And as I mentioned,
00:03:28.820 --> 00:03:31.030
it's not just light waves that do this.
00:03:31.030 --> 00:03:33.923
Waves in general can do all of the above.
|
Wave transmission | https://www.youtube.com/watch?v=3fY-DB9D6uU | vtt | https://www.youtube.com/api/timedtext?v=3fY-DB9D6uU&ei=v1WUZf_-KfyNmLAPt9m1gAQ&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245295&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=07344F48449CD96919862CE570056E04F75B720B.C4AB49E8F1A8B28E3CD32439479D1808252CBFDD&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.450 --> 00:00:02.050
- [Instructor] When we're
talking about waves,
00:00:02.050 --> 00:00:06.650
transmission is when a
wave passes from a material
00:00:06.650 --> 00:00:08.300
into another one.
00:00:08.300 --> 00:00:11.170
For example, here we have the sun,
00:00:11.170 --> 00:00:14.580
93 million miles away on average,
00:00:14.580 --> 00:00:17.390
and imagine the different materials
00:00:17.390 --> 00:00:20.260
that the light has to
travel through from the sun
00:00:20.260 --> 00:00:24.320
to, say, hit one of these sand
particles right over here.
00:00:24.320 --> 00:00:27.410
Think about what it needs
to be transmitted through.
00:00:27.410 --> 00:00:30.780
What's going to travel
through 93 million miles
00:00:30.780 --> 00:00:32.130
of the vacuum of space,
00:00:32.130 --> 00:00:34.270
and that's one of the amazing
things about light waves
00:00:34.270 --> 00:00:35.430
is that they don't need a medium.
00:00:35.430 --> 00:00:38.660
They can travel through
vacuum, through emptiness,
00:00:38.660 --> 00:00:41.510
but then it's gonna travel
through several miles
00:00:41.510 --> 00:00:43.230
of Earth's atmosphere.
00:00:43.230 --> 00:00:44.800
So it's going to travel
through several miles
00:00:44.800 --> 00:00:45.633
of Earth's atmosphere.
00:00:45.633 --> 00:00:48.321
It will hit these, the
lenses of these sunglasses,
00:00:48.321 --> 00:00:50.880
the light will travel through
the lenses of the sunglass,
00:00:50.880 --> 00:00:54.280
little sunglass has some
width or some depth to it,
00:00:54.280 --> 00:00:56.570
and then it'll go out onto the other side
00:00:56.570 --> 00:00:59.790
and it will hit the sand right over here.
00:00:59.790 --> 00:01:01.340
Now, one thing you might realize
00:01:01.340 --> 00:01:05.600
is the amount of transmission
and what gets transmitted
00:01:05.600 --> 00:01:08.270
is dependent on the
wavelengths of the wave,
00:01:08.270 --> 00:01:10.030
in this case, the wavelengths of light,
00:01:10.030 --> 00:01:13.630
and also about the material
that they are going through.
00:01:13.630 --> 00:01:16.240
So for example, these
sunglasses right over here,
00:01:16.240 --> 00:01:20.100
many sunglasses try to keep out
UV light, ultraviolet light,
00:01:20.100 --> 00:01:22.150
which is a higher frequency
than visible light,
00:01:22.150 --> 00:01:24.010
but that's what causes sunburns
00:01:24.010 --> 00:01:26.440
and that can also damage your eyes.
00:01:26.440 --> 00:01:29.670
So those high frequencies
are not making it through.
00:01:29.670 --> 00:01:32.990
And we can also see that this
sunglass right over here,
00:01:32.990 --> 00:01:34.850
it kind of has an orange color,
00:01:34.850 --> 00:01:36.940
which means that things that are closer
00:01:36.940 --> 00:01:38.130
to that end of the spectrum,
00:01:38.130 --> 00:01:40.390
closer to the red, the
oranges, and the yellows
00:01:40.390 --> 00:01:41.310
are getting through,
00:01:41.310 --> 00:01:44.030
which means that it's
filtering out blue light.
00:01:44.030 --> 00:01:47.350
So the blue light, isn't getting
transmitted through as much
00:01:47.350 --> 00:01:49.370
as say the red, orange, and yellow light
00:01:49.370 --> 00:01:52.370
and that's why we see this
as red, orange, or yellow.
00:01:52.370 --> 00:01:53.203
And then, of course,
00:01:53.203 --> 00:01:55.390
the light will get to that sand particle.
00:01:55.390 --> 00:01:57.010
Now transmission, as I mentioned,
00:01:57.010 --> 00:01:59.310
it isn't just about light waves.
00:01:59.310 --> 00:02:00.280
We could talk about
00:02:00.280 --> 00:02:02.010
one of our other favorite types of waves,
00:02:02.010 --> 00:02:04.060
for example, sound waves.
00:02:04.060 --> 00:02:05.880
If you are in a room,
00:02:05.880 --> 00:02:08.210
you have probably experienced the fact
00:02:08.210 --> 00:02:10.930
that even if you were to close the door,
00:02:10.930 --> 00:02:13.230
and I do this a lot because
I record a lot of videos.
00:02:13.230 --> 00:02:16.320
This is me in my little
closet recording a video.
00:02:16.320 --> 00:02:19.040
This is a top view for
what I'm doing right now.
00:02:19.040 --> 00:02:21.840
A lot of times my kids are
in other parts of the house
00:02:21.840 --> 00:02:24.650
and they're making a lot of noise.
00:02:24.650 --> 00:02:26.020
And as we've talked about,
00:02:26.020 --> 00:02:28.920
sound waves are nothing but
traveling pressure waves
00:02:28.920 --> 00:02:29.753
through the air.
00:02:29.753 --> 00:02:32.200
Those air particles are
knocking one into another.
00:02:32.200 --> 00:02:33.840
But in order to make it to me,
00:02:33.840 --> 00:02:35.460
they need to get through that wall,
00:02:35.460 --> 00:02:36.430
and the way they do that
00:02:36.430 --> 00:02:39.280
is they get transmitted through that wall.
00:02:39.280 --> 00:02:41.800
So those air particles make the particles
00:02:41.800 --> 00:02:43.420
or make the atoms or the molecules
00:02:43.420 --> 00:02:46.450
in the walls start vibrating,
they bump into each other,
00:02:46.450 --> 00:02:49.720
and then the particles on
the other side of the wall
00:02:49.720 --> 00:02:52.400
will bump into the air
in my little closet,
00:02:52.400 --> 00:02:55.000
and then we will have, once again,
00:02:55.000 --> 00:02:57.020
the sound waves make it to me.
00:02:57.020 --> 00:02:59.510
Now, the overall magnitude of sound,
00:02:59.510 --> 00:03:02.050
the volume of the sound,
will likely be diminished
00:03:02.050 --> 00:03:04.440
and not all of the
frequencies of the sound
00:03:04.440 --> 00:03:06.030
will be transmitted equally.
00:03:06.030 --> 00:03:08.140
Different frequencies of sound waves
00:03:08.140 --> 00:03:11.000
are better at traveling
through certain materials,
00:03:11.000 --> 00:03:14.010
just as we talked about with light waves.
00:03:14.010 --> 00:03:15.930
So now when you look at
the world around you,
00:03:15.930 --> 00:03:17.480
or you hear the world around you,
00:03:17.480 --> 00:03:19.270
or look at other types of waves,
00:03:19.270 --> 00:03:21.210
just think about how it's transmitting
00:03:21.210 --> 00:03:23.723
from one material into another.
|
Refraction in a glass of water | https://www.youtube.com/watch?v=sv8-y7N0Ryw | vtt | https://www.youtube.com/api/timedtext?v=sv8-y7N0Ryw&ei=v1WUZb7YNfGnp-oPtuyS0A0&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245295&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=C3889C69EE6FC332C9CC154D616EE68E63919CBE.85B511D8DF9C728348469DB3BF23ABC9D978E952&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.290 --> 00:00:01.800
- [Instructor] So
something very interesting
00:00:01.800 --> 00:00:04.050
is clearly going on when
we look at this pencil
00:00:04.050 --> 00:00:06.000
dipped in this cup of water.
00:00:06.000 --> 00:00:10.390
We would expect if maybe there
was no water in this glass
00:00:10.390 --> 00:00:13.250
that we would just see the
pencil continue straight down
00:00:13.250 --> 00:00:16.740
in a line that looks something like that.
00:00:16.740 --> 00:00:19.240
But that's clearly not what we are seeing.
00:00:19.240 --> 00:00:21.340
It looks like, once we fill it with water,
00:00:21.340 --> 00:00:22.830
at least to our eye,
00:00:22.830 --> 00:00:25.760
it looks like the pencil
gets bent or broken
00:00:25.760 --> 00:00:27.500
or bent in some way.
00:00:27.500 --> 00:00:28.850
And this notion,
00:00:28.850 --> 00:00:31.790
you might have heard
people call it refraction.
00:00:31.790 --> 00:00:34.490
But it's interesting
thing about exactly why
00:00:34.490 --> 00:00:35.780
this is happening.
00:00:35.780 --> 00:00:37.580
And I'll give you a hint.
00:00:37.580 --> 00:00:40.170
This is all about the bending of light.
00:00:40.170 --> 00:00:42.700
And it's not just light that can get bent
00:00:42.700 --> 00:00:45.490
as it goes from one medium into another.
00:00:45.490 --> 00:00:48.463
It can be any kind of wave.
00:00:48.463 --> 00:00:51.100
So let's think about
what's going on over here.
00:00:51.100 --> 00:00:52.760
So first, let's think about
the part of the pencil
00:00:52.760 --> 00:00:54.370
that is above the water.
00:00:54.370 --> 00:00:56.360
So this part right over here,
00:00:56.360 --> 00:00:59.710
the light is actually
reflecting off of this pencil,
00:00:59.710 --> 00:01:02.120
and then it's bouncing
straight into our eye.
00:01:02.120 --> 00:01:03.970
So just imagine a path from this dot
00:01:03.970 --> 00:01:05.250
straight into your eye.
00:01:05.250 --> 00:01:07.980
Once again, from here, it's
going straight into your eye.
00:01:07.980 --> 00:01:11.360
When we go over here, it still
doesn't look too distorted.
00:01:11.360 --> 00:01:13.750
So you have light that's
going straight to your eye.
00:01:13.750 --> 00:01:15.614
It's going through the side of the glass
00:01:15.614 --> 00:01:18.553
and then getting to your eye.
00:01:18.553 --> 00:01:20.120
But then once we get under the water,
00:01:20.120 --> 00:01:21.360
something's interesting.
00:01:21.360 --> 00:01:25.430
You would expect the point
that would have been here
00:01:25.430 --> 00:01:27.340
would then go straight to your eye
00:01:27.340 --> 00:01:28.980
just like everything up here.
00:01:28.980 --> 00:01:30.730
But it turns out that that light,
00:01:30.730 --> 00:01:35.020
once it transitions from going
from the water to the glass
00:01:35.020 --> 00:01:37.300
and then the air, it bends.
00:01:37.300 --> 00:01:40.630
So at the interface between the media,
00:01:40.630 --> 00:01:42.080
between those different materials
00:01:42.080 --> 00:01:43.620
that the light is traveling through,
00:01:43.620 --> 00:01:44.935
instead of going towards your eye,
00:01:44.935 --> 00:01:48.470
it gets bent, in this case to our left.
00:01:48.470 --> 00:01:50.850
And so that's why when
we look straight on here,
00:01:50.850 --> 00:01:53.999
we don't see anything in
this region right over here.
00:01:53.999 --> 00:01:56.516
But the light that was going
00:01:56.516 --> 00:02:00.610
from the pencil towards
this part of the glass,
00:02:00.610 --> 00:02:02.250
which typically you would not see,
00:02:02.250 --> 00:02:04.070
that would have typically
just gone straight
00:02:04.070 --> 00:02:06.250
in that direction and not hit your eye,
00:02:06.250 --> 00:02:08.600
well, now that is getting refracted.
00:02:08.600 --> 00:02:10.330
It's getting bent to the left
00:02:10.330 --> 00:02:12.860
so that now that light hits your eye.
00:02:12.860 --> 00:02:15.990
So that's why you see what
looks like a broken pencil.
00:02:15.990 --> 00:02:19.120
It's all about the light getting bent
00:02:19.120 --> 00:02:22.550
as it exits the water
and goes into the glass
00:02:22.550 --> 00:02:23.923
and then the air.
|
Mechanical waves and light | https://www.youtube.com/watch?v=3dGiR32OxE8 | vtt | https://www.youtube.com/api/timedtext?v=3dGiR32OxE8&ei=v1WUZdOhNp24mLAPxImamA4&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245295&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=E34B6AB268E359E016AE53167E996533808F31E8.7F17E1784E9E306A1F44DC4EC13F3B2A8103F0A9&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.550 --> 00:00:02.870
- [Instructor] Let's talk about waves.
00:00:02.870 --> 00:00:05.360
So let's imagine that
you were to take a string
00:00:05.360 --> 00:00:08.150
and attach it at one end to a wall,
00:00:08.150 --> 00:00:09.390
and then on the other end,
00:00:09.390 --> 00:00:11.700
you were to wiggle it up and down.
00:00:11.700 --> 00:00:14.280
Well, then you would have made a wave.
00:00:14.280 --> 00:00:17.690
You would see a pattern
that looks like this.
00:00:17.690 --> 00:00:21.010
Now, what would be a good
definition for a wave?
00:00:21.010 --> 00:00:24.610
Well, we could call it
a traveling disturbance.
00:00:24.610 --> 00:00:26.130
Well, what does that mean?
00:00:26.130 --> 00:00:27.750
Well, we're disturbing the rope.
00:00:27.750 --> 00:00:30.180
If we didn't move it, if
we just held it straight,
00:00:30.180 --> 00:00:32.360
it might look something like that,
00:00:32.360 --> 00:00:34.350
or it might just hang down a little bit,
00:00:34.350 --> 00:00:37.700
but clearly we are now
moving it up and down,
00:00:37.700 --> 00:00:40.740
and those movements are
disturbing that rope
00:00:40.740 --> 00:00:44.190
and that disturbance can
move along that rope.
00:00:44.190 --> 00:00:46.200
Now, we see waves not just in ropes
00:00:46.200 --> 00:00:48.020
that are moving up and down.
00:00:48.020 --> 00:00:50.590
You have probably seen water waves.
00:00:50.590 --> 00:00:52.740
If you were to take a
tank of water like this
00:00:52.740 --> 00:00:55.110
and if you were to start
pressing on one end
00:00:55.110 --> 00:00:56.400
of the water here,
00:00:56.400 --> 00:00:59.760
you would see these wave forms that start.
00:00:59.760 --> 00:01:03.600
We can also see that with
sound and sound waves.
00:01:03.600 --> 00:01:04.760
You might not realize it,
00:01:04.760 --> 00:01:07.000
but the sound of my voice right now
00:01:07.000 --> 00:01:09.700
is actually just a traveling compression,
00:01:09.700 --> 00:01:12.270
or disturbance in the air
that is getting to your ear.
00:01:12.270 --> 00:01:13.860
And that little hairs in your ears
00:01:13.860 --> 00:01:16.980
can sense those changes
in pressure from the air
00:01:16.980 --> 00:01:19.820
and your mind perceives that as sound.
00:01:19.820 --> 00:01:23.010
And once again, this is
a traveling disturbance.
00:01:23.010 --> 00:01:24.740
You have particles that
have high pressure,
00:01:24.740 --> 00:01:26.880
and then they knock into
the particles next to them,
00:01:26.880 --> 00:01:29.090
that then knock into the
particles next to them.
00:01:29.090 --> 00:01:31.430
So if you were to be able to
observe this in slow motion,
00:01:31.430 --> 00:01:34.230
you would see these high
pressure parts right over here
00:01:34.230 --> 00:01:36.450
could be traveling, say to the right.
00:01:36.450 --> 00:01:38.440
And even though this
might be a pressure wave
00:01:38.440 --> 00:01:39.950
that's traveling through the air,
00:01:39.950 --> 00:01:41.530
we can represent it in a way
00:01:41.530 --> 00:01:43.530
that looks a lot like our first rope
00:01:43.530 --> 00:01:45.490
that we were moving up and down.
00:01:45.490 --> 00:01:48.720
Areas where things are
high, in the sound example,
00:01:48.720 --> 00:01:49.740
that's high pressure,
00:01:49.740 --> 00:01:51.510
and you have areas where things are low,
00:01:51.510 --> 00:01:54.110
in the sound example,
that is low pressure.
00:01:54.110 --> 00:01:56.880
Now, when we talk about waves,
there are common properties.
00:01:56.880 --> 00:01:58.700
For example, we might wanna know,
00:01:58.700 --> 00:02:00.500
how much are we getting disturbed
00:02:00.500 --> 00:02:02.440
from what we would call the equilibrium?
00:02:02.440 --> 00:02:03.760
You could view that as maybe
00:02:03.760 --> 00:02:05.840
the middle state right over there.
00:02:05.840 --> 00:02:08.450
Well, if we're getting
disturbed that much,
00:02:08.450 --> 00:02:10.500
we could call that the amplitude.
00:02:10.500 --> 00:02:13.280
That's how much we are going above
00:02:13.280 --> 00:02:15.610
or below that equilibrium.
00:02:15.610 --> 00:02:18.370
This would be the amplitude as well.
00:02:18.370 --> 00:02:20.720
We could think about how far is it
00:02:20.720 --> 00:02:22.870
from the same points on the wave.
00:02:22.870 --> 00:02:26.010
So if we go from one peak to another peak,
00:02:26.010 --> 00:02:28.870
well, we could call that the wavelength,
00:02:28.870 --> 00:02:31.770
and you could just do it from
any one point on the wave
00:02:31.770 --> 00:02:33.840
that's just like it on the wave again.
00:02:33.840 --> 00:02:35.840
So that would be the same wavelength
00:02:35.840 --> 00:02:38.240
as our original wavelength
right over there.
00:02:38.240 --> 00:02:41.720
You might hear the term
frequency of a wave.
00:02:41.720 --> 00:02:43.450
And one way to think about that
00:02:43.450 --> 00:02:46.470
is if you were to just
observe our original rope,
00:02:46.470 --> 00:02:47.407
and if you were to say,
00:02:47.407 --> 00:02:50.770
"How many times does it go all the way up,
00:02:50.770 --> 00:02:52.970
all the way down, and then back up.
00:02:52.970 --> 00:02:54.870
so it completes a full cycle?
00:02:54.870 --> 00:02:57.190
How many times can it do that in a second?
00:02:57.190 --> 00:02:59.760
If it does that five times in second,
00:02:59.760 --> 00:03:02.220
then someone might say it has a frequency
00:03:02.220 --> 00:03:04.650
of five cycles per second.
00:03:04.650 --> 00:03:07.000
Now, everything that we
have just talked about,
00:03:07.000 --> 00:03:09.400
these are called mechanical waves.
00:03:09.400 --> 00:03:10.560
It's a special category,
00:03:10.560 --> 00:03:13.200
probably the ones that
you will see most often.
00:03:13.200 --> 00:03:17.100
Now, mechanical waves need
a medium to travel through.
00:03:17.100 --> 00:03:19.610
In the rope example,
the medium was the rope.
00:03:19.610 --> 00:03:21.440
In the water example, it's the water.
00:03:21.440 --> 00:03:24.950
In the sound example,
the medium is the air.
00:03:24.950 --> 00:03:28.060
Now, there are things that
can be described as waves
00:03:28.060 --> 00:03:30.200
that don't need a medium.
00:03:30.200 --> 00:03:31.280
In particular,
00:03:31.280 --> 00:03:33.300
and this is kind of mind boggling,
00:03:33.300 --> 00:03:36.460
is that light can be considered a wave.
00:03:36.460 --> 00:03:39.340
If we think about the
different frequencies of light,
00:03:39.340 --> 00:03:42.970
our brain perceives that
as different colors.
00:03:42.970 --> 00:03:45.830
And if we think about
the amplitude of light,
00:03:45.830 --> 00:03:49.150
our brain perceives that
as the intensity of light,
00:03:49.150 --> 00:03:50.300
how bright it is.
00:03:50.300 --> 00:03:51.980
And even more mindblowing,
00:03:51.980 --> 00:03:54.780
visible light are just certain frequencies
00:03:54.780 --> 00:03:57.690
of what we would call
electromagnetic waves.
00:03:57.690 --> 00:04:01.270
There's actually higher frequencies
of electromagnetic waves
00:04:01.270 --> 00:04:03.470
that have all sorts of applications.
00:04:03.470 --> 00:04:05.290
You might have heard of ultraviolet light,
00:04:05.290 --> 00:04:07.770
or x-rays, or gamma rays.
00:04:07.770 --> 00:04:09.900
Similarly, there's lower
wavelengths of light.
00:04:09.900 --> 00:04:12.770
You might have heard things
like infrared, or radio waves.
00:04:12.770 --> 00:04:14.670
These are all just different frequencies
00:04:14.670 --> 00:04:17.903
of what's known as electromagnetic waves.
|
Kinetic energy | https://www.youtube.com/watch?v=QFDVhfYu8HU | vtt | https://www.youtube.com/api/timedtext?v=QFDVhfYu8HU&ei=wFWUZcLfDM63p-oPjY-ZGA&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245296&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=2F0C4945E829A719AF1EEA2B4766F90A4882694B.1BDFF480EB4D6CC641AE87B3D9863BBF1C5459EE&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.200 --> 00:00:01.120
- [Instructor] Hello, everyone.
00:00:01.120 --> 00:00:04.050
Let's talk about kinetic energy.
00:00:04.050 --> 00:00:06.580
Now, kinetic might be an unfamiliar word,
00:00:06.580 --> 00:00:08.170
but it just comes from a Greek word
00:00:08.170 --> 00:00:10.050
that means of motion,
00:00:10.050 --> 00:00:13.920
so kinetic energy is energy from motion.
00:00:13.920 --> 00:00:16.760
Any massive object that is in motion then
00:00:16.760 --> 00:00:20.280
has kinetic energy, but how much?
00:00:20.280 --> 00:00:23.040
First, let's consider some comparisons.
00:00:23.040 --> 00:00:26.930
This nice rat family, papa,
mama, brother, and sister
00:00:26.930 --> 00:00:29.270
are sitting down to dinner at a long table
00:00:29.270 --> 00:00:31.760
passing blocks of cheese back-and-forth.
00:00:31.760 --> 00:00:33.650
Papa rat asks for the cheddar cheese
00:00:33.650 --> 00:00:36.020
and there are two identical blocks.
00:00:36.020 --> 00:00:38.950
Brother rat pushes one and
sister rat pushes the other,
00:00:38.950 --> 00:00:40.930
so that the second cheese is traveling
00:00:40.930 --> 00:00:43.320
twice as fast as the first cheese.
00:00:43.320 --> 00:00:44.770
Which piece of cheddar cheese
00:00:44.770 --> 00:00:47.633
do you think has more kinetic energy?
00:00:49.090 --> 00:00:51.990
Yes, it's the one going faster.
00:00:51.990 --> 00:00:55.080
Now, papa rat doesn't need
both pieces of cheddar,
00:00:55.080 --> 00:00:57.360
so he eats one and sends one back,
00:00:57.360 --> 00:00:59.410
along with this small piece of Swiss
00:00:59.410 --> 00:01:02.150
that weighs half as much
as the piece of cheddar.
00:01:02.150 --> 00:01:04.490
Papa rat has better
manners than his children,
00:01:04.490 --> 00:01:07.660
so he sends them both
back at the same speed.
00:01:07.660 --> 00:01:09.470
Which piece of cheese would you think
00:01:09.470 --> 00:01:11.333
has more kinetic energy now?
00:01:14.020 --> 00:01:16.770
Yes, the heavier or more massive object,
00:01:16.770 --> 00:01:20.100
in this case, the cheddar,
will have more kinetic energy.
00:01:20.100 --> 00:01:22.380
Let's make it a little more complicated.
00:01:22.380 --> 00:01:24.120
Brother and sister rat are full,
00:01:24.120 --> 00:01:27.040
so they send the cheeses
back for mama rat.
00:01:27.040 --> 00:01:29.340
Brother rat pushes the
larger piece of cheddar
00:01:29.340 --> 00:01:31.990
and sister rat pushes the
smaller piece of Swiss
00:01:31.990 --> 00:01:36.210
so that the Swiss is going
twice as fast as the cheddar.
00:01:36.210 --> 00:01:38.673
Now, which cheese has more kinetic energy?
00:01:40.870 --> 00:01:44.440
In fact, it turns out that it's
the Swiss in this scenario.
00:01:44.440 --> 00:01:47.570
Kinetic energy depends
on both mass and speed,
00:01:47.570 --> 00:01:50.800
but the dependence on speed is stronger.
00:01:50.800 --> 00:01:53.110
This estimation of kinetic energy
00:01:53.110 --> 00:01:55.290
can be quantified in an equation
00:01:55.290 --> 00:01:58.170
that lets us calculate
kinetic energy exactly.
00:01:58.170 --> 00:02:00.500
We said kinetic energy depends on the mass
00:02:00.500 --> 00:02:03.740
and the speed, which we'll
write as V for velocity,
00:02:03.740 --> 00:02:07.440
so we can start with K E equals M times V.
00:02:07.440 --> 00:02:10.580
But we said that it
depends more on the speed,
00:02:10.580 --> 00:02:14.020
so the velocity here is actually squared.
00:02:14.020 --> 00:02:16.830
This means that if an
object's mass doubles,
00:02:16.830 --> 00:02:19.420
its kinetic energy also doubles,
00:02:19.420 --> 00:02:21.280
but if its speed doubles,
00:02:21.280 --> 00:02:24.160
the kinetic energy actually quadruples.
00:02:24.160 --> 00:02:26.180
And there's also a constant factor of 1/2
00:02:26.180 --> 00:02:27.530
at the beginning of the equation,
00:02:27.530 --> 00:02:29.380
but we won't go into
the details of the math
00:02:29.380 --> 00:02:30.750
of deriving this today.
00:02:30.750 --> 00:02:33.370
So, this is the equation
for kinetic energy,
00:02:33.370 --> 00:02:36.290
1/2 M V squared.
00:02:36.290 --> 00:02:39.340
Let's apply this equation
to our cheesy example.
00:02:39.340 --> 00:02:42.384
Say the Swiss has a mass of .05 kilograms,
00:02:42.384 --> 00:02:45.510
which makes the cheddar's
mass .1 kilograms.
00:02:45.510 --> 00:02:48.240
When both cheeses have the same speed,
00:02:48.240 --> 00:02:50.060
say two meters per second,
00:02:50.060 --> 00:02:53.642
the cheddar's kinetic energy
is 1/2 times .1 kilograms,
00:02:53.642 --> 00:02:57.708
times two meters per second
squared, which is .2 Joules.
00:02:57.708 --> 00:03:01.829
The Swiss's kinetic energy
is 1/2 times .05 kilograms
00:03:01.829 --> 00:03:05.073
times two meters per second
squared, which is .1 Joules,
00:03:05.073 --> 00:03:07.550
or half the kinetic energy of the cheddar.
00:03:07.550 --> 00:03:09.697
So we can see that at the same speed,
00:03:09.697 --> 00:03:11.677
the cheddar has more kinetic energy
00:03:11.677 --> 00:03:14.177
because it has more mass.
00:03:14.177 --> 00:03:17.293
But when the Swiss has a speed
of four meters per second
00:03:17.293 --> 00:03:20.030
and the cheddar still has a
speed of two meters per second,
00:03:20.030 --> 00:03:24.740
the Swiss's kinetic energy is
now 1/2 times .05 kilograms
00:03:24.740 --> 00:03:29.560
times four meters per second
squared, which is .4 Joules.
00:03:29.560 --> 00:03:31.480
So now, the kinetic energy of the Swiss
00:03:31.480 --> 00:03:33.900
is twice the kinetic
energy of the cheddar.
00:03:33.900 --> 00:03:36.730
So we can see that even though
the cheddar has more mass
00:03:36.730 --> 00:03:38.510
the Swiss has more kinetic energy
00:03:38.510 --> 00:03:41.080
because it's going faster.
00:03:41.080 --> 00:03:42.660
In summary, kinetic energy
00:03:42.660 --> 00:03:45.370
is the motion energy of an object.
00:03:45.370 --> 00:03:48.740
The equation for kinetic
energy is 1/2 M V squared.
00:03:48.740 --> 00:03:52.060
So as mass increases,
kinetic energy increases,
00:03:52.060 --> 00:03:55.530
like the more massive
cheddar versus the Swiss,
00:03:55.530 --> 00:03:57.230
and as velocity increases,
00:03:57.230 --> 00:03:59.480
kinetic energy increases even more,
00:03:59.480 --> 00:04:03.040
like the speedy Swiss
versus the slower cheddar.
00:04:03.040 --> 00:04:03.873
Thanks for watching,
00:04:03.873 --> 00:04:05.983
and I hope you learned a
little bit of something.
|
Electromagnetism | https://www.youtube.com/watch?v=E77NeY5Zmk8 | vtt | https://www.youtube.com/api/timedtext?v=E77NeY5Zmk8&ei=wFWUZe7JDIuahcIPloyD-AM&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245296&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=CE5E9379E03CDCA8DF2FA6513FBC729D4F6C17FB.A8B356FE49577BCF8D97F16096DD2893E616E6E7&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.130 --> 00:00:01.380
- [Instructor] You know what a magnet is,
00:00:01.380 --> 00:00:05.180
but did you know that some
magnets can be turned on and off?
00:00:05.180 --> 00:00:09.200
One type of temporary magnet
is called an electromagnet.
00:00:09.200 --> 00:00:12.010
So what is electromagnetism?
00:00:12.010 --> 00:00:14.750
Well, the hint is in the name itself.
00:00:14.750 --> 00:00:17.520
Electro for electrical,
00:00:17.520 --> 00:00:21.260
and magnet for, well, magnet.
00:00:21.260 --> 00:00:23.670
Let's take a moment to
look at the definition
00:00:23.670 --> 00:00:25.860
of what an electromagnet is.
00:00:25.860 --> 00:00:29.630
Electromagnets are materials
that become magnets
00:00:29.630 --> 00:00:31.593
in the presence of electricity.
00:00:32.460 --> 00:00:34.320
But how does that even happen?
00:00:34.320 --> 00:00:35.380
Well, it turns out
00:00:35.380 --> 00:00:38.100
that electrically-charged
particles in motion
00:00:38.100 --> 00:00:41.280
actually have small
magnetic fields around them.
00:00:41.280 --> 00:00:45.530
So, if we run electricity through a wire,
00:00:45.530 --> 00:00:48.303
a magnetic field will be
created around the wire.
00:00:49.160 --> 00:00:52.500
Now, we can control the
strength of this magnetic field
00:00:52.500 --> 00:00:54.320
in a couple of ways.
00:00:54.320 --> 00:00:57.680
We can move more electric
charges through the wire
00:00:57.680 --> 00:00:58.933
at a faster rate,
00:00:59.850 --> 00:01:03.313
and we do this by increasing
the electrical current.
00:01:04.720 --> 00:01:08.800
The second way is to increase the density
00:01:08.800 --> 00:01:10.223
of the charged particles,
00:01:11.740 --> 00:01:16.010
and we can do this by
looping the wire into a coil.
00:01:16.010 --> 00:01:18.110
This gives us more charged particles
00:01:18.110 --> 00:01:20.810
with magnetic fields in a small space,
00:01:20.810 --> 00:01:23.210
strengthening the magnetic force.
00:01:23.210 --> 00:01:26.150
The other thing we can
control with electromagnets
00:01:26.150 --> 00:01:29.790
is the direction of the magnetic field,
00:01:29.790 --> 00:01:32.370
and we can do this by
changing the direction
00:01:32.370 --> 00:01:34.170
of the electricity.
00:01:34.170 --> 00:01:37.400
So if we go back to this
wire example from earlier
00:01:37.400 --> 00:01:38.760
and change the direction
00:01:38.760 --> 00:01:41.370
of the electricity
running through that wire,
00:01:41.370 --> 00:01:45.500
well, the magnetic fields
will also change direction.
00:01:45.500 --> 00:01:48.010
This makes electromagnets quite different
00:01:48.010 --> 00:01:49.890
from permanent magnets.
00:01:49.890 --> 00:01:51.510
So let's take a look at that
00:01:51.510 --> 00:01:55.933
and compare permanent
magnets to electromagnets.
00:01:58.110 --> 00:02:00.630
Electromagnets are typically made
00:02:00.630 --> 00:02:03.210
of loops of wire and a coil.
00:02:03.210 --> 00:02:06.010
The wire is typically
made of metal like copper
00:02:06.010 --> 00:02:07.840
and wrapped around pieces of metal
00:02:07.840 --> 00:02:10.680
like iron, nickel, or cobalt.
00:02:10.680 --> 00:02:12.980
This is different from a permanent magnet
00:02:12.980 --> 00:02:15.603
because permanent magnets
don't need this wire.
00:02:16.820 --> 00:02:19.530
Permanent magnets also have fixed poles.
00:02:19.530 --> 00:02:23.140
You can't change the north and
south poles on these magnets,
00:02:23.140 --> 00:02:25.900
but as we now know, for electromagnets,
00:02:25.900 --> 00:02:28.870
we can change these poles
by changing the direction
00:02:28.870 --> 00:02:30.570
of the electrical current.
00:02:30.570 --> 00:02:33.450
So, if we have an electromagnet
with a north and south pole
00:02:33.450 --> 00:02:34.440
that looks like this
00:02:34.440 --> 00:02:36.890
and a current flowing in this direction,
00:02:36.890 --> 00:02:38.860
well, we can change the poles
00:02:38.860 --> 00:02:40.633
and the direction of the current.
00:02:42.110 --> 00:02:45.050
Permanent magnets have a fixed strength,
00:02:45.050 --> 00:02:46.480
but we just talked about
00:02:46.480 --> 00:02:49.270
how we can change the
strength of electromagnets,
00:02:49.270 --> 00:02:52.600
so electromagnets have
adjustable strength.
00:02:52.600 --> 00:02:55.900
And finally, electromagnets
need a power source
00:02:55.900 --> 00:02:58.130
in order to generate
the electricity required
00:02:58.130 --> 00:03:00.140
to produce magnetic fields.
00:03:00.140 --> 00:03:03.240
Permanent magnets do
not need a power source,
00:03:03.240 --> 00:03:06.550
but this means that we can
also turn electromagnets
00:03:06.550 --> 00:03:07.690
on and off,
00:03:07.690 --> 00:03:10.030
which is pretty cool
when you think about it.
00:03:10.030 --> 00:03:10.863
On the other hand,
00:03:10.863 --> 00:03:13.650
permanent magnets are always on.
00:03:13.650 --> 00:03:15.680
Now, you might be thinking
00:03:15.680 --> 00:03:19.220
if electrical charge can affect magnetism,
00:03:19.220 --> 00:03:23.060
can magnetism affect electrical charge?
00:03:23.060 --> 00:03:26.590
Absolutely, let's look
at how we can do that.
00:03:26.590 --> 00:03:30.930
The only way to do this is by
changing the magnetic field
00:03:30.930 --> 00:03:32.860
around the charged particles.
00:03:32.860 --> 00:03:36.070
This can be done by moving magnets closer
00:03:36.070 --> 00:03:38.650
or further away from the particles
00:03:38.650 --> 00:03:41.520
or by spinning the magnets.
00:03:41.520 --> 00:03:45.610
In fact, spinning magnets is
how most of the electricity
00:03:45.610 --> 00:03:48.380
we use in cities and homes is generated.
00:03:48.380 --> 00:03:51.260
A turbine spins a magnet inside a coil
00:03:51.260 --> 00:03:52.890
to produce electricity,
00:03:52.890 --> 00:03:55.750
and since electromagnets
need a power source,
00:03:55.750 --> 00:03:58.690
this turbine is powered by wind.
00:03:58.690 --> 00:04:00.870
So you can see why electromagnetism
00:04:00.870 --> 00:04:02.840
is an incredibly important force,
00:04:02.840 --> 00:04:06.160
and this isn't the only
important application of it.
00:04:06.160 --> 00:04:09.330
We use electromagnets in all
sorts of other applications,
00:04:09.330 --> 00:04:13.423
from motors to speakers
and even medical scanners.
|
Fields | https://www.youtube.com/watch?v=JmIXAN9qBUw | vtt | https://www.youtube.com/api/timedtext?v=JmIXAN9qBUw&ei=v1WUZa-KKqOivdIPuJ-LeA&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245295&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=ABE7816D0E2BB8B0C5AE0FCF703EA85B8ED8E716.10EEE91AE85943B91CEF773BEE59638CE04C9E38&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.350 --> 00:00:02.890
- If you hold a ball up
in the air and let it go,
00:00:02.890 --> 00:00:05.890
you know it's going to fall, but why?
00:00:05.890 --> 00:00:08.190
Nothing is touching it once you let it go.
00:00:08.190 --> 00:00:10.330
How can there be a force on it?
00:00:10.330 --> 00:00:13.170
Well, this is because
Earth's gravitational force
00:00:13.170 --> 00:00:17.210
is pulling the ball and
gravity is a non-contact force.
00:00:17.210 --> 00:00:19.940
Non-contact forces don't
have to touch an object
00:00:19.940 --> 00:00:21.710
to exert a force on it.
00:00:21.710 --> 00:00:24.840
Instead, these forces act over a region.
00:00:24.840 --> 00:00:27.100
So if an object is in that region,
00:00:27.100 --> 00:00:29.250
it will be affected by the force.
00:00:29.250 --> 00:00:32.720
In this case, the ball is in
Earth's gravitational field,
00:00:32.720 --> 00:00:35.880
and so it feels an attractive
force towards the Earth
00:00:35.880 --> 00:00:37.852
and the ball falls to the ground.
00:00:37.852 --> 00:00:41.350
Field forces include non-contact forces,
00:00:41.350 --> 00:00:45.518
such as electric, magnetic,
00:00:45.518 --> 00:00:49.270
and of course, gravitational forces.
00:00:49.270 --> 00:00:51.700
So since these forces are non-contact,
00:00:51.700 --> 00:00:54.340
they can exert a force on
objects they aren't touching,
00:00:54.340 --> 00:00:55.960
but how do these objects know
00:00:55.960 --> 00:00:57.950
if there's a force between them?
00:00:57.950 --> 00:01:00.380
To explain these non-contact forces,
00:01:00.380 --> 00:01:02.490
scientists eventually developed the idea
00:01:02.490 --> 00:01:04.340
that these objects were
surrounded by something
00:01:04.340 --> 00:01:05.513
called a field.
00:01:06.420 --> 00:01:08.230
So what is a field?
00:01:08.230 --> 00:01:10.860
A field extends through
space from an object
00:01:10.860 --> 00:01:12.720
with certain physical properties.
00:01:12.720 --> 00:01:14.330
What are those?
00:01:14.330 --> 00:01:17.150
Well, for gravitational forces,
00:01:17.150 --> 00:01:19.650
these affect objects with mass.
00:01:19.650 --> 00:01:23.241
So any object with mass
has a gravitational field
00:01:23.241 --> 00:01:27.360
surrounding it that points
towards the object's center.
00:01:27.360 --> 00:01:29.430
The further you move away from the object,
00:01:29.430 --> 00:01:32.900
the less dense the field and
weaker the field becomes.
00:01:32.900 --> 00:01:36.080
Electric forces effect charged objects.
00:01:36.080 --> 00:01:40.470
So an electric field surrounds
any object with a net charge,
00:01:40.470 --> 00:01:44.469
and the direction of this field
will depend on the charge.
00:01:44.469 --> 00:01:47.510
Magnetic fields will affect magnets
00:01:47.510 --> 00:01:50.173
and any other material
with magnetic properties.
00:01:51.410 --> 00:01:55.136
Each spot on a field has two
things associated with it:
00:01:55.136 --> 00:01:58.700
magnitude and direction.
00:01:58.700 --> 00:01:59.890
And these help us predict
00:01:59.890 --> 00:02:02.000
what forces objects will experience
00:02:02.000 --> 00:02:03.760
when they're in the field.
00:02:03.760 --> 00:02:07.530
So let's look at an example
to help understand this.
00:02:07.530 --> 00:02:09.700
Say we have a planet.
00:02:09.700 --> 00:02:12.470
Now, the planet has a lot of mass
00:02:12.470 --> 00:02:14.490
so we know it's going to be surrounded
00:02:14.490 --> 00:02:16.159
by a gravitational field
00:02:16.159 --> 00:02:19.790
that points towards the
center of the planet.
00:02:19.790 --> 00:02:21.780
I can draw these little field lines
00:02:21.780 --> 00:02:25.500
that show the direction of
the field and its strength.
00:02:25.500 --> 00:02:27.400
As we move away from the planet,
00:02:27.400 --> 00:02:28.890
the field will start to weaken,
00:02:28.890 --> 00:02:32.470
and I'm going to represent
that by a less dense field
00:02:32.470 --> 00:02:33.930
with these arrows.
00:02:33.930 --> 00:02:35.610
Now, let's say there's an asteroid
00:02:35.610 --> 00:02:38.120
moving near the planet in this direction.
00:02:38.120 --> 00:02:41.265
I know that the asteroid,
as it's shown here,
00:02:41.265 --> 00:02:45.230
is in the outskirts of this
planet's gravitational field.
00:02:45.230 --> 00:02:48.490
So it is going to feel some
gravitational attraction
00:02:48.490 --> 00:02:49.690
towards the planet,
00:02:49.690 --> 00:02:52.960
which we can draw with this vector, Fg,
00:02:52.960 --> 00:02:55.340
which is force of gravity.
00:02:55.340 --> 00:02:57.210
Now, because it's attracted to the planet,
00:02:57.210 --> 00:03:00.310
the astroid will continue
to move towards the planet.
00:03:00.310 --> 00:03:03.070
And the closer the asteroid
gets to the planet,
00:03:03.070 --> 00:03:04.014
the stronger the field
00:03:04.014 --> 00:03:07.412
and the stronger the force
of attraction it will feel.
00:03:07.412 --> 00:03:11.160
And so in this way,
scientists can use fields
00:03:11.160 --> 00:03:13.410
to help predict behavior of objects
00:03:13.410 --> 00:03:16.060
experiencing non-contact forces.
00:03:16.060 --> 00:03:18.180
And all of this may sound kind of odd,
00:03:18.180 --> 00:03:21.269
but you probably already
think about forces this way.
00:03:21.269 --> 00:03:23.910
For example, if we go back to the ball
00:03:23.910 --> 00:03:25.700
that you know is going to fall,
00:03:25.700 --> 00:03:28.430
you knew this because the
force of gravity from Earth
00:03:28.430 --> 00:03:30.960
was going to pull the
ball towards the Earth.
00:03:30.960 --> 00:03:33.430
But now you also know that that's because
00:03:33.430 --> 00:03:36.400
Earth's gravity is a field force.
00:03:36.400 --> 00:03:40.550
And so the ball is in the
field of gravity for Earth
00:03:40.550 --> 00:03:43.950
and experiences an attractive
gravitational force.
00:03:43.950 --> 00:03:46.842
So while fields may sound mysterious,
00:03:46.842 --> 00:03:51.842
they really just mean that a
force is felt over a distance.
00:03:52.060 --> 00:03:54.625
Gravitational, electric,
and magnetic forces
00:03:54.625 --> 00:03:56.400
are all field forces,
00:03:56.400 --> 00:03:58.241
which means they act over distance
00:03:58.241 --> 00:04:00.753
and can affect a lot of objects.
|
Magnetic forces | https://www.youtube.com/watch?v=Ikto_172Vak | vtt | https://www.youtube.com/api/timedtext?v=Ikto_172Vak&ei=v1WUZeeYMYKUhcIPspOV0Aw&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245295&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=B047A2C1A211E71CD0DF4E703391C9CD7FFBE717.4B06CC1A637F91B74E3D6DC1F48385C20A76ACB6&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.120 --> 00:00:01.350
- [Instructor] Let's talk about magnets
00:00:01.350 --> 00:00:03.310
and magnetic forces.
00:00:03.310 --> 00:00:05.690
Magnets are these neat
objects that are able
00:00:05.690 --> 00:00:08.100
to attract metals like iron.
00:00:08.100 --> 00:00:10.310
Magnets are used in all sorts of things,
00:00:10.310 --> 00:00:13.650
from holding paper on your refrigerator,
00:00:13.650 --> 00:00:17.180
to computers, to compasses.
00:00:17.180 --> 00:00:20.490
So magnets can be used
to stick things together,
00:00:20.490 --> 00:00:23.890
point us in the right
direction, and even lift things,
00:00:23.890 --> 00:00:27.360
and they do this through magnetic forces.
00:00:27.360 --> 00:00:30.930
If you've handled two magnets,
you felt magnetic forces,
00:00:30.930 --> 00:00:33.670
even when the magnets
weren't touching each other.
00:00:33.670 --> 00:00:37.950
That's because magnetic
forces are non-contact forces,
00:00:37.950 --> 00:00:40.660
which just means they
can affect other objects
00:00:40.660 --> 00:00:42.210
they aren't even touching.
00:00:42.210 --> 00:00:46.560
Magnets will attract or repel each other,
00:00:46.560 --> 00:00:51.010
and this attraction or
repulsion is a magnetic force.
00:00:51.010 --> 00:00:54.680
But magnetic forces don't
affect everything the same way.
00:00:54.680 --> 00:00:56.820
Otherwise, a magnet would stick to you,
00:00:56.820 --> 00:00:58.640
not just a refrigerator.
00:00:58.640 --> 00:01:01.680
In this video, we're going to
talk about the magnetic forces
00:01:01.680 --> 00:01:03.313
between two magnets.
00:01:04.200 --> 00:01:06.900
So why do magnet sometimes
attract each other
00:01:06.900 --> 00:01:09.610
and other times repel each other?
00:01:09.610 --> 00:01:14.470
Well, this has to do with the
orientation of the magnets.
00:01:14.470 --> 00:01:17.440
Orientation is really just a fancy word
00:01:17.440 --> 00:01:21.600
for how the magnets are positioned
compared to one another.
00:01:21.600 --> 00:01:24.800
You see, it turns out that
each magnet has a north
00:01:24.800 --> 00:01:26.910
and south pole,
00:01:26.910 --> 00:01:30.870
but what does this have to do
with attraction or repulsion?
00:01:30.870 --> 00:01:33.570
Well, as you may have
heard, opposites attract.
00:01:33.570 --> 00:01:37.490
So, if you face the
north pole of one magnet
00:01:37.490 --> 00:01:41.430
to the south pole of
another magnet, guess what?
00:01:41.430 --> 00:01:43.900
They will be attracted to each other.
00:01:43.900 --> 00:01:46.350
But if you turn one of
those magnets around
00:01:46.350 --> 00:01:49.400
so that you have two north
poles facing each other,
00:01:49.400 --> 00:01:50.940
they will repel.
00:01:50.940 --> 00:01:52.080
And the same thing would happen
00:01:52.080 --> 00:01:54.610
if it was two south
pulse facing each other.
00:01:54.610 --> 00:01:58.630
So the direction of the magnetic
force completely depends
00:01:58.630 --> 00:02:01.150
on the orientation of the magnets.
00:02:01.150 --> 00:02:03.850
Orientation, though, is just one thing
00:02:03.850 --> 00:02:05.710
that affects magnetic forces.
00:02:05.710 --> 00:02:08.420
The strength of magnetic forces depends
00:02:08.420 --> 00:02:10.130
on a couple of things.
00:02:10.130 --> 00:02:12.093
For one, distance.
00:02:13.040 --> 00:02:14.830
If you've ever held two magnets,
00:02:14.830 --> 00:02:17.930
you may have noticed that
when you move them closer,
00:02:17.930 --> 00:02:20.310
they seem to almost jump together.
00:02:20.310 --> 00:02:23.260
Or if you try to push
two light poles together,
00:02:23.260 --> 00:02:25.370
they get harder and
harder to hold together
00:02:25.370 --> 00:02:27.050
the closer you get.
00:02:27.050 --> 00:02:30.740
This is because magnetic
forces depend on distance.
00:02:30.740 --> 00:02:32.840
The closer the two magnets are together,
00:02:32.840 --> 00:02:34.770
the stronger the force between them.
00:02:34.770 --> 00:02:39.063
So, as the distance decreases,
the force increases,
00:02:39.900 --> 00:02:41.970
but the farther away they are,
00:02:41.970 --> 00:02:44.130
the weaker the magnetic force is.
00:02:44.130 --> 00:02:48.610
So, distance increases; force decreases.
00:02:48.610 --> 00:02:50.340
The other big factor that affects
00:02:50.340 --> 00:02:52.330
how strong a magnetic force is...
00:02:52.330 --> 00:02:54.610
Well, the magnets themselves.
00:02:54.610 --> 00:02:56.550
Sub magnets are really weak,
00:02:56.550 --> 00:02:58.750
like a lot of refrigerator magnets.
00:02:58.750 --> 00:03:01.560
Others are so strong that even tiny ones
00:03:01.560 --> 00:03:04.460
can be almost impossible to pull apart.
00:03:04.460 --> 00:03:07.070
Some of these stronger
magnets are even used
00:03:07.070 --> 00:03:10.630
to make high-speed trains
levitate off the ground.
00:03:10.630 --> 00:03:14.410
And yes, this rectangle
is supposed to be a train.
00:03:14.410 --> 00:03:16.830
While my drawing isn't amazing,
00:03:16.830 --> 00:03:20.553
the fact that magnetic forces
can levitate a train is.
|
Gravitational forces | https://www.youtube.com/watch?v=atogJ2qw9Ko | vtt | https://www.youtube.com/api/timedtext?v=atogJ2qw9Ko&ei=wFWUZdC1CY6Kp-oP4uq48AU&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245296&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=31F5C1452EAA38415450BF6A3D4938FB5822CFA4.EB74C8908407A457E5F0155CA8231D7DBF9EA6B4&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.130 --> 00:00:02.120
- [Instructor] When you
hear the word gravity,
00:00:02.120 --> 00:00:04.430
you probably just think of things falling,
00:00:04.430 --> 00:00:06.610
like an apple from a tree.
00:00:06.610 --> 00:00:08.240
But did you know it's also the reason
00:00:08.240 --> 00:00:10.910
why your lamp is staying on the floor?
00:00:10.910 --> 00:00:13.000
That's because gravity is so much more
00:00:13.000 --> 00:00:14.730
than things falling down.
00:00:14.730 --> 00:00:17.089
Gravitational forces are
these invisible forces
00:00:17.089 --> 00:00:20.260
that pull objects together.
00:00:20.260 --> 00:00:22.880
So gravitational force
is actually attracting
00:00:22.880 --> 00:00:25.819
the lamp to the floor
and these forces exist
00:00:25.819 --> 00:00:28.470
between all objects with mass.
00:00:28.470 --> 00:00:29.771
So let's write these key points out
00:00:29.771 --> 00:00:32.630
about gravitational
forces, which I'm going
00:00:32.630 --> 00:00:34.403
to use GF to represent.
00:00:35.380 --> 00:00:38.720
We said they are attractive forces,
00:00:38.720 --> 00:00:43.720
and that they exist between
all objects with mass.
00:00:44.630 --> 00:00:49.630
Objects with mass, to explain this,
00:00:50.100 --> 00:00:52.810
we first need to remember
a couple of things.
00:00:52.810 --> 00:00:57.000
Mass is how much matter objects have,
00:00:57.000 --> 00:01:00.590
and matter is the stuff
an object is made of.
00:01:00.590 --> 00:01:03.680
Any object with mass generates
a gravitational pull.
00:01:03.680 --> 00:01:05.710
So, there is a gravitational force
00:01:05.710 --> 00:01:08.720
of attraction between every object.
00:01:08.720 --> 00:01:10.390
The amount of gravitational force
00:01:10.390 --> 00:01:14.223
between two objects will
depend on two things:
00:01:15.420 --> 00:01:20.203
the masses of the two objects
and the distance between them.
00:01:21.470 --> 00:01:23.950
The mass of each object is proportional
00:01:23.950 --> 00:01:26.130
to the gravitational force.
00:01:26.130 --> 00:01:29.550
This means that the
more mass an object has
00:01:29.550 --> 00:01:31.993
the stronger it's gravitational force.
00:01:33.010 --> 00:01:36.470
And, now, we can understand
why gravity makes things fall.
00:01:36.470 --> 00:01:39.380
The Earth has massive, literally.
00:01:39.380 --> 00:01:43.400
It's almost six septillion kilograms.
00:01:43.400 --> 00:01:48.080
That's a 6 with 24 zeros after it.
00:01:48.080 --> 00:01:50.573
So, it generates a huge attractive force.
00:01:51.720 --> 00:01:55.160
For comparison, my lamp
is only one kilogram,
00:01:55.160 --> 00:01:57.630
which is why if I jump, I fall towards
00:01:57.630 --> 00:01:59.613
the Earth and not towards my lamp.
00:02:00.720 --> 00:02:03.070
But we said the mass of the object
00:02:03.070 --> 00:02:04.670
is just one factor affecting
00:02:04.670 --> 00:02:07.310
the strength of its gravitational force.
00:02:07.310 --> 00:02:10.040
The other is the distance between objects.
00:02:10.040 --> 00:02:12.450
The more distance between the objects
00:02:12.450 --> 00:02:14.993
the weaker the gravitational
pull between them.
00:02:16.210 --> 00:02:18.680
For small objects without much mass,
00:02:18.680 --> 00:02:21.690
it doesn't take much distance
for their gravitational forces
00:02:21.690 --> 00:02:25.023
between each other to be so
weak that we don't notice them.
00:02:26.210 --> 00:02:28.030
For something like the Earth, you have
00:02:28.030 --> 00:02:31.560
to go really far away to not be affected
00:02:31.560 --> 00:02:34.100
by its gravitational force of attraction.
00:02:34.100 --> 00:02:39.100
I mean, look at the moon, it's
almost 240,000 miles away,
00:02:39.900 --> 00:02:43.620
that's almost 400,000 kilometers away,
00:02:43.620 --> 00:02:46.970
and it still feels effects
from Earth's gravity.
00:02:46.970 --> 00:02:50.060
That's why it's orbiting
us, but since the moon
00:02:50.060 --> 00:02:53.830
is also a pretty massive
object, we do experience
00:02:53.830 --> 00:02:57.320
the effects of its
gravitational pull on the Earth.
00:02:57.320 --> 00:03:00.740
This is why we have tides,
the moon's gravitational force
00:03:00.740 --> 00:03:03.080
will pull on Earth's water, which results
00:03:03.080 --> 00:03:05.073
in us having high and low tides.
00:03:06.100 --> 00:03:08.980
Now, you might be wondering if
gravity can affect the moon,
00:03:08.980 --> 00:03:12.470
or cause tides, how can
we even move around?
00:03:12.470 --> 00:03:14.230
Why aren't we just face
planted on the ground
00:03:14.230 --> 00:03:17.280
because Earth's gravity
is pulling us towards it?
00:03:17.280 --> 00:03:21.050
It turns out that actually
gravity is a pretty weak force.
00:03:21.050 --> 00:03:23.270
We only even notice its
effects when an object
00:03:23.270 --> 00:03:26.000
is massive, like planets or stars,
00:03:26.000 --> 00:03:28.150
and the gravitational force on you
00:03:28.150 --> 00:03:32.420
is way weaker than most
forces you exert every day.
00:03:32.420 --> 00:03:35.490
In fact, every time you
pick up a glass of water,
00:03:35.490 --> 00:03:38.490
you're overpowering the
entire mass of Earth.
00:03:38.490 --> 00:03:39.553
How cool is that?
|
Action and reaction forces | https://www.youtube.com/watch?v=Hm7B-xXJ1uM | vtt | https://www.youtube.com/api/timedtext?v=Hm7B-xXJ1uM&ei=wFWUZd-9Fsi-mLAP58Cj4Ag&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245296&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=2D1010AAD3B3D14351523630153B9A7E0C5EDC23.5B69D508A7F74193051D671BBFD178E03D9F0ED4&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.300 --> 00:00:02.160
- [Lecturer] You've probably
heard the phrase that
00:00:02.160 --> 00:00:03.530
for every force,
00:00:03.530 --> 00:00:06.340
there's an equal and
opposite reaction force.
00:00:06.340 --> 00:00:10.200
And this is also known as
Newton's third law of motion,
00:00:10.200 --> 00:00:14.240
but it's also one of the most
misunderstood laws of physics.
00:00:14.240 --> 00:00:16.330
So that's why we're going
to dig into it a little bit
00:00:16.330 --> 00:00:17.930
in this video.
00:00:17.930 --> 00:00:21.700
So I have two examples here
where Newton's third law
00:00:21.700 --> 00:00:24.570
or this notion of an
action and a reaction force
00:00:24.570 --> 00:00:25.960
is happening.
00:00:25.960 --> 00:00:27.960
So over here, you have this plane flying
00:00:27.960 --> 00:00:30.620
and the plane is able to move forward
00:00:30.620 --> 00:00:33.960
by pushing air particles
through these jet engines.
00:00:33.960 --> 00:00:36.760
So these air particles are pushed outward
00:00:36.760 --> 00:00:41.280
at a very, very high velocity
out the back of the engines.
00:00:41.280 --> 00:00:43.800
If you are to enlarge one
of those air particles,
00:00:43.800 --> 00:00:46.790
let's say, this is this
purple dot right over here.
00:00:46.790 --> 00:00:49.530
There is a force that
is being exerted on it
00:00:49.530 --> 00:00:51.080
by the jet engine.
00:00:51.080 --> 00:00:55.240
And that force is going in that direction.
00:00:55.240 --> 00:00:58.700
So what is the equal and
opposite reaction force?
00:00:58.700 --> 00:01:01.100
Well, the equal and
opposite reaction force
00:01:01.100 --> 00:01:04.390
is not also are occurring
on that molecule.
00:01:04.390 --> 00:01:07.320
It's what the molecule
is doing to the plane.
00:01:07.320 --> 00:01:09.790
The equal and opposite reaction force
00:01:09.790 --> 00:01:11.813
is that the molecule
is going to be pushing
00:01:11.813 --> 00:01:16.110
on the jet engine with an
equal but an opposite force.
00:01:16.110 --> 00:01:18.670
So it's going to go in
the opposite direction.
00:01:18.670 --> 00:01:22.380
And that's how the jet is
able to accelerate forward
00:01:22.380 --> 00:01:25.190
by pushing on these particles
and accelerating them
00:01:25.190 --> 00:01:27.530
backward by exerting a force on them.
00:01:27.530 --> 00:01:30.140
The equal and opposite force is the force
00:01:30.140 --> 00:01:31.210
that the particles,
00:01:31.210 --> 00:01:33.930
those molecules of air
are exerting on the jet
00:01:33.930 --> 00:01:35.810
and moving it forward.
00:01:35.810 --> 00:01:39.380
The same thing here is
going on with this rocket.
00:01:39.380 --> 00:01:42.280
You have some rocket fuel in there.
00:01:42.280 --> 00:01:43.210
It gets ignited.
00:01:43.210 --> 00:01:44.360
It explodes.
00:01:44.360 --> 00:01:46.070
And as it explodes,
00:01:46.070 --> 00:01:51.070
there's a force that exerts
on those little molecules
00:01:51.170 --> 00:01:55.113
and that force is going in this direction.
00:01:56.290 --> 00:01:57.400
But as it does that,
00:01:57.400 --> 00:01:59.620
there's an equal and opposite force
00:01:59.620 --> 00:02:03.360
that the molecules are
exerting on the rocket.
00:02:03.360 --> 00:02:06.950
The rocket is having a force acted on it,
00:02:06.950 --> 00:02:10.010
once again, equal and opposite.
00:02:10.010 --> 00:02:12.810
So it's important to realize
that the reaction force
00:02:12.810 --> 00:02:14.680
is not on the same object.
00:02:14.680 --> 00:02:16.040
It's on the other object.
00:02:16.040 --> 00:02:19.700
If one object is putting
an action force on another,
00:02:19.700 --> 00:02:22.200
then the second object is
putting a reaction force
00:02:22.200 --> 00:02:23.580
on the first.
00:02:23.580 --> 00:02:26.730
The forces do not cancel out.
00:02:26.730 --> 00:02:28.480
It's also important to realize that
00:02:28.480 --> 00:02:31.000
both forces are generated in pairs
00:02:31.000 --> 00:02:33.490
and happen at the exact same time.
00:02:33.490 --> 00:02:35.320
There's no delay.
00:02:35.320 --> 00:02:37.720
We can look at other examples of this.
00:02:37.720 --> 00:02:40.620
This is a scenario that I would
never want to be caught in
00:02:40.620 --> 00:02:42.010
being drifting through space.
00:02:42.010 --> 00:02:44.870
Now this astronaut here has
some type of a rocket pack
00:02:44.870 --> 00:02:46.030
that might help him move around.
00:02:46.030 --> 00:02:49.170
But let's say that your
rocket pack ran out of fuel
00:02:49.170 --> 00:02:51.160
and you're just drifting through space.
00:02:51.160 --> 00:02:54.563
How can you get back to your spaceship?
00:02:55.440 --> 00:02:57.710
Well, if you have a
wrench or something on you
00:02:57.710 --> 00:02:59.150
that you can throw,
00:02:59.150 --> 00:03:01.683
if you can take that wrench,
00:03:03.070 --> 00:03:06.400
and if you can push that
wrench in that direction,
00:03:06.400 --> 00:03:09.310
and let's say your spaceship
is over here to the left.
00:03:09.310 --> 00:03:11.900
Well, the equal and
opposite force is the force
00:03:11.900 --> 00:03:14.880
that the wrench is going to
exert on you, the astronaut,
00:03:14.880 --> 00:03:17.840
and then it will push
you in that direction
00:03:17.840 --> 00:03:20.160
and accelerate you in that direction.
00:03:20.160 --> 00:03:21.230
So that's a useful thing,
00:03:21.230 --> 00:03:23.930
if you're ever get caught
drifting through space.
00:03:23.930 --> 00:03:25.820
But you could do an experiment right now.
00:03:25.820 --> 00:03:28.210
Press on the table in front of you.
00:03:28.210 --> 00:03:29.630
When you press on that table,
00:03:29.630 --> 00:03:32.660
you're clearly putting
a force onto that table.
00:03:32.660 --> 00:03:35.660
If your table is soft, you
will see it get compressed.
00:03:35.660 --> 00:03:38.880
But notice your finger itself
is also getting compressed.
00:03:38.880 --> 00:03:40.380
And the whole reason why
you can even feel that
00:03:40.380 --> 00:03:42.040
is because your finger
is getting compressed.
00:03:42.040 --> 00:03:43.910
And that is the equal and opposite force
00:03:43.910 --> 00:03:46.740
that the table is putting on your finger.
00:03:46.740 --> 00:03:50.570
And this can happen at very,
very large distances as well.
00:03:50.570 --> 00:03:53.350
The whole reason why the Moon
is in orbit around the Earth
00:03:53.350 --> 00:03:56.330
is because there's a gravitational force
00:03:56.330 --> 00:03:59.260
of Earth's mass acting on the Moon.
00:03:59.260 --> 00:04:03.610
But there's an equal and
opposite force of the Moon
00:04:03.610 --> 00:04:05.987
acting on Earth.
00:04:05.987 --> 00:04:08.510
And it's actually not
that the Moon is rotating
00:04:08.510 --> 00:04:09.343
around the Earth.
00:04:09.343 --> 00:04:11.280
It's actually, they're
both rotating around
00:04:11.280 --> 00:04:14.000
the center of mass of their combination,
00:04:14.000 --> 00:04:16.530
that just happens to be
so much closer to Earth.
00:04:16.530 --> 00:04:18.440
It's actually within Earth's volume
00:04:18.440 --> 00:04:21.920
that it looks like the Moon
is rotating around the Earth.
00:04:21.920 --> 00:04:24.230
And this isn't just celestial bodies.
00:04:24.230 --> 00:04:26.460
I weigh 165 pounds.
00:04:26.460 --> 00:04:30.000
That is the force that Earth
is acting on me due to gravity,
00:04:30.000 --> 00:04:33.180
but it turns out that there's
an equal and opposite force
00:04:33.180 --> 00:04:38.180
of 165 pounds that I am
pulling on Earth with.
00:04:38.570 --> 00:04:40.050
So I will leave you there.
00:04:40.050 --> 00:04:41.200
Look around the world.
00:04:41.200 --> 00:04:42.700
This is happening everywhere.
00:04:42.700 --> 00:04:43.950
For every force,
00:04:43.950 --> 00:04:46.470
there's an equal and
opposite reaction force.
00:04:46.470 --> 00:04:47.890
But they don't cancel out
00:04:47.890 --> 00:04:50.483
because they're acting
on different bodies.
|
Net force | https://www.youtube.com/watch?v=fwDWJZkrtUE | vtt | https://www.youtube.com/api/timedtext?v=fwDWJZkrtUE&ei=wFWUZcf2AYmPmLAPhvCQiAg&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245296&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=081E3B6004E52B7F56EFDA509AF0D12C5BBA4E7B.0C42C1695DFB7CB54AD4EB18CFD54564CB499348&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.560 --> 00:00:02.900
- [Instructor] Let's say
that we are in deep space,
00:00:02.900 --> 00:00:05.100
and there is this asteroid here,
00:00:05.100 --> 00:00:07.590
that compared to us, is stationary,
00:00:07.590 --> 00:00:10.150
or relative to us is stationary.
00:00:10.150 --> 00:00:13.480
And what we wanna do is
we wanna start to move it.
00:00:13.480 --> 00:00:18.480
So what we do is we attach
a rocket to one side,
00:00:20.530 --> 00:00:22.540
and then we ignite that rocket,
00:00:22.540 --> 00:00:26.920
and it starts to send all
this super-heated gas,
00:00:26.920 --> 00:00:30.130
all of these particles to the right.
00:00:30.130 --> 00:00:32.450
Well, what do you think that's
going to do to the asteroid?
00:00:32.450 --> 00:00:37.120
Well, it's going to push on
the asteroid in that direction.
00:00:37.120 --> 00:00:39.490
Or you could say it's
going to exert a force
00:00:39.490 --> 00:00:40.570
on that asteroid.
00:00:40.570 --> 00:00:42.980
And we could show that force like this,
00:00:42.980 --> 00:00:45.190
where the strength of that force,
00:00:45.190 --> 00:00:49.420
or the magnitude of the force,
is the length of this line.
00:00:49.420 --> 00:00:50.460
And then the direction,
00:00:50.460 --> 00:00:53.810
I will specify or show with that arrow.
00:00:53.810 --> 00:00:57.780
So fair enough, I will be
pushing towards the left.
00:00:57.780 --> 00:00:59.310
And when I push to the left,
00:00:59.310 --> 00:01:01.870
it doesn't just start to move
the asteroid to the left,
00:01:01.870 --> 00:01:05.330
it actually will accelerate
the asteroid to the left.
00:01:05.330 --> 00:01:07.790
So the longer that this rocket is running,
00:01:07.790 --> 00:01:10.980
it's going to make the
asteroid move to the left
00:01:10.980 --> 00:01:14.020
faster and faster and faster.
00:01:14.020 --> 00:01:15.800
But let's think about another example.
00:01:15.800 --> 00:01:19.360
Let's say that you and
one of your friends,
00:01:19.360 --> 00:01:21.330
you have a little bit of miscommunication,
00:01:21.330 --> 00:01:23.820
and they went and put an identical rocket
00:01:23.820 --> 00:01:26.423
on this side of the asteroid.
00:01:27.330 --> 00:01:31.120
And y'all ignited it
at the exact same time.
00:01:31.120 --> 00:01:34.370
So this one is going to
push in the other direction.
00:01:34.370 --> 00:01:35.480
What do you think is going to happen
00:01:35.480 --> 00:01:38.130
if these happened at the exact same time?
00:01:38.130 --> 00:01:40.230
Even though there's
now twice as much force
00:01:40.230 --> 00:01:41.900
being exerted on this asteroid,
00:01:41.900 --> 00:01:45.160
it's going in opposite
directions, so they zero out,
00:01:45.160 --> 00:01:47.690
and so there's zero net force.
00:01:47.690 --> 00:01:51.270
And so this asteroid won't
be accelerated at all.
00:01:51.270 --> 00:01:53.150
Now let's say that a third friend
00:01:53.150 --> 00:01:55.110
wanted to correct this situation,
00:01:55.110 --> 00:01:57.870
and this isn't necessarily the
most efficient way to do it,
00:01:57.870 --> 00:02:02.270
but what they do is they
put another identical rocket
00:02:02.270 --> 00:02:06.173
right over here, and
let's say ignite that.
00:02:07.060 --> 00:02:08.423
Now what will happen?
00:02:09.290 --> 00:02:11.600
Well, now you had the original two forces
00:02:11.600 --> 00:02:13.220
that net out to each other.
00:02:13.220 --> 00:02:15.630
But now you have this also this new force,
00:02:15.630 --> 00:02:17.880
which I will make in purple,
'cause it's a purple rocket.
00:02:17.880 --> 00:02:22.880
And so that new force,
you could draw like this,
00:02:23.630 --> 00:02:26.630
to show, all right, that
will now be the net force,
00:02:26.630 --> 00:02:28.550
'cause you have the
equivalent of two rockets
00:02:28.550 --> 00:02:29.800
going in the left direction,
00:02:29.800 --> 00:02:32.100
and one rocket going
in the right direction.
00:02:32.100 --> 00:02:34.570
Or another way we could draw that is
00:02:34.570 --> 00:02:38.270
we have two rockets going
in the left direction,
00:02:38.270 --> 00:02:41.150
so that would have a force
that looks like this.
00:02:41.150 --> 00:02:43.380
And then we have one going
in the right direction.
00:02:43.380 --> 00:02:46.000
And so if you were to net it out,
00:02:46.000 --> 00:02:48.450
this is equivalent to
just having one rocket
00:02:48.450 --> 00:02:49.930
that we originally saw.
00:02:49.930 --> 00:02:52.460
That's equivalent to just going back
00:02:52.460 --> 00:02:54.770
to what we originally saw.
00:02:54.770 --> 00:02:57.610
So the important takeaway from this video
00:02:57.610 --> 00:03:00.680
is that it's not just about
the force that's being applied.
00:03:00.680 --> 00:03:02.820
If you wanna think about how something
00:03:02.820 --> 00:03:05.400
might be accelerated,
and in what direction,
00:03:05.400 --> 00:03:07.160
you need to think about the net force,
00:03:07.160 --> 00:03:10.503
because some of the forces
could counteract each other.
|
Force, mass and acceleration | https://www.youtube.com/watch?v=YBErdKxFvUA | vtt | https://www.youtube.com/api/timedtext?v=YBErdKxFvUA&ei=wFWUZfn2E5KPp-oP4tWduA4&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245296&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=29338081C11DE0387ABB7FA5AE13D159CF7338E5.A45B87E37A09B3C48B23AC85397CA951486C95EE&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.000 --> 00:00:03.022
- So I have three different
asteroids over here
00:00:03.022 --> 00:00:05.500
and they have different masses.
00:00:05.500 --> 00:00:08.920
And we'll talk a lot more
about what mass means.
00:00:08.920 --> 00:00:10.618
But one way to think about it is,
00:00:10.618 --> 00:00:13.800
how much stuff there is there.
00:00:13.800 --> 00:00:15.320
There's other ways to think about it.
00:00:15.320 --> 00:00:17.920
And so let's say that this first asteroid
00:00:17.920 --> 00:00:22.880
is twice the mass of either
of these two smaller ones.
00:00:22.880 --> 00:00:26.040
And these two smaller
ones have the same mass.
00:00:26.040 --> 00:00:28.590
Now, we've attached the back of a rocket
00:00:28.590 --> 00:00:30.310
to each of these asteroids.
00:00:30.310 --> 00:00:32.729
In fact, this one over
here has two rockets,
00:00:32.729 --> 00:00:33.900
and we're going to assume
00:00:33.900 --> 00:00:35.750
that all of the rockets are equivalent
00:00:35.750 --> 00:00:37.270
and we ignite them all.
00:00:37.270 --> 00:00:42.270
And so they all exert the same
force each on the asteroid.
00:00:42.810 --> 00:00:43.740
So for example,
00:00:43.740 --> 00:00:48.740
we have a net force acting
leftward on this large asteroid.
00:00:49.070 --> 00:00:53.700
We have the same net force
acting on this smaller asteroid,
00:00:53.700 --> 00:00:55.380
also going to the left.
00:00:55.380 --> 00:00:57.329
And on this other smaller asteroid,
00:00:57.329 --> 00:01:02.150
we have two times that net
force acting to the left.
00:01:02.150 --> 00:01:04.600
So what I want you to
do is pause this video
00:01:04.600 --> 00:01:07.019
and think about which of these asteroids
00:01:07.019 --> 00:01:09.320
is going to be accelerated the most,
00:01:09.320 --> 00:01:10.720
and which of these asteroids
00:01:10.720 --> 00:01:12.803
is going to be accelerated the least.
00:01:14.520 --> 00:01:15.353
All right.
00:01:15.353 --> 00:01:20.110
So you might have an intuition
that the larger the force,
00:01:20.110 --> 00:01:22.630
the more acceleration you might see.
00:01:22.630 --> 00:01:24.390
So let me write it like this.
00:01:24.390 --> 00:01:27.830
So you might get a sense that
if you increase your force,
00:01:27.830 --> 00:01:31.430
that that's also going to
increase your acceleration.
00:01:31.430 --> 00:01:34.620
And it does turn out that
that is indeed the case.
00:01:34.620 --> 00:01:37.680
Now, the other notion that you might have
00:01:37.680 --> 00:01:40.260
is that the more of the
stuff that there is,
00:01:40.260 --> 00:01:42.450
the more mass that you have,
00:01:42.450 --> 00:01:45.300
the harder it is to accelerate it.
00:01:45.300 --> 00:01:48.070
So if you're mass is larger,
00:01:48.070 --> 00:01:51.150
than your acceleration is lower.
00:01:51.150 --> 00:01:54.860
And it turns out that these
things are all proportional.
00:01:54.860 --> 00:01:56.620
So for example,
00:01:56.620 --> 00:02:00.350
if we just compare these
two masses right over here,
00:02:00.350 --> 00:02:02.890
they have the same net force acting on it.
00:02:02.890 --> 00:02:04.370
And I keep saying net force,
00:02:04.370 --> 00:02:06.410
that means you just net
out all of the forces
00:02:06.410 --> 00:02:07.900
acting in a certain dimension.
00:02:07.900 --> 00:02:10.340
For example, if I had
another identical rocket
00:02:10.340 --> 00:02:12.970
acting in the opposite direction,
00:02:12.970 --> 00:02:15.390
they would net out, and this
asteroid right over here
00:02:15.390 --> 00:02:17.700
wouldn't be accelerated at all.
00:02:17.700 --> 00:02:19.480
But going back to our example here,
00:02:19.480 --> 00:02:22.050
we have the same net force
00:02:22.050 --> 00:02:24.410
acting on each of these asteroids.
00:02:24.410 --> 00:02:25.580
But the first asteroid
00:02:25.580 --> 00:02:28.530
has twice the mass of the second asteroid.
00:02:28.530 --> 00:02:31.030
So how do you think the
accelerations will relate?
00:02:31.930 --> 00:02:34.080
Well, as you might imagine,
00:02:34.080 --> 00:02:36.530
the acceleration on the larger asteroid
00:02:36.530 --> 00:02:39.900
is going to be half the
acceleration on this asteroid.
00:02:39.900 --> 00:02:41.330
Or another way to think about it,
00:02:41.330 --> 00:02:44.562
this asteroid is going to
have twice the acceleration
00:02:44.562 --> 00:02:46.780
as this first asteroid.
00:02:46.780 --> 00:02:50.340
And that's because it has half the mass.
00:02:50.340 --> 00:02:53.880
And one way you can relate
force, mass, and acceleration,
00:02:53.880 --> 00:02:56.161
and this is one of the
most important equations
00:02:56.161 --> 00:02:57.940
in all of physics,
00:02:57.940 --> 00:02:59.210
is that force
00:02:59.210 --> 00:03:04.210
is going to be equal to
mass times acceleration,
00:03:04.820 --> 00:03:06.560
or I could say the magnitude of the force
00:03:06.560 --> 00:03:07.890
is equal to the mass
00:03:07.890 --> 00:03:10.430
times the magnitude of the acceleration.
00:03:10.430 --> 00:03:12.870
So notice, in this
example right over here,
00:03:12.870 --> 00:03:16.270
our forces are the same, but
the masses are different.
00:03:16.270 --> 00:03:18.900
If I have half the mass
as I have over here,
00:03:18.900 --> 00:03:21.480
I'm going to have twice the acceleration.
00:03:21.480 --> 00:03:23.340
And that might make intuitive sense
00:03:23.340 --> 00:03:25.490
if you've ever tried
to apply the same force
00:03:25.490 --> 00:03:27.250
to something that has a small mass
00:03:27.250 --> 00:03:29.960
versus something that has a large mass.
00:03:29.960 --> 00:03:33.900
Now, if we compare these two asteroids,
00:03:33.900 --> 00:03:36.690
they have the same mass here,
00:03:36.690 --> 00:03:38.930
but the force here, the net force,
00:03:38.930 --> 00:03:41.680
acting in that left direction, is double.
00:03:41.680 --> 00:03:44.240
So if you double the force,
don't change the mass.
00:03:44.240 --> 00:03:45.922
Well, then you're going to
have twice the acceleration.
00:03:45.922 --> 00:03:49.680
So this is going to have twice
the acceleration of this one,
00:03:49.680 --> 00:03:50.513
and this one's
00:03:50.513 --> 00:03:52.930
going to have twice the
acceleration of that one.
00:03:52.930 --> 00:03:54.215
But the important thing to realize
00:03:54.215 --> 00:03:58.403
is how force, mass, and
acceleration are connected.
|
Frames of reference | https://www.youtube.com/watch?v=ypQPSH1qkI4 | vtt | https://www.youtube.com/api/timedtext?v=ypQPSH1qkI4&ei=wFWUZeDrC4yahcIPz5aTiA8&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245296&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=1CD21443D4810B0D164F03ACEA5A32D03FC5A566.28774A06CC3B0B35B9156831F576D9603DD00BDD&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.150 --> 00:00:02.140
- [Instructor] When we
make new discoveries
00:00:02.140 --> 00:00:04.330
we need to be able to
share them with others.
00:00:04.330 --> 00:00:06.570
And the first thing we
have to do is make sure
00:00:06.570 --> 00:00:08.620
everyone is on the same page.
00:00:08.620 --> 00:00:12.040
We do this by using units
and frames of reference,
00:00:12.040 --> 00:00:14.740
which are also called reference frames.
00:00:14.740 --> 00:00:16.930
We talk about units in another video,
00:00:16.930 --> 00:00:20.360
so let's look at what a
frame of reference is.
00:00:20.360 --> 00:00:23.390
Let's say this blue box thing is a car,
00:00:23.390 --> 00:00:26.290
and it's going 45 miles per hour.
00:00:26.290 --> 00:00:28.240
Someone standing on the side of the road
00:00:28.240 --> 00:00:31.690
would see it pass at 45 miles per hour.
00:00:31.690 --> 00:00:36.690
Now, if this yellow truck
is going 40 miles per hour
00:00:37.570 --> 00:00:40.070
someone sitting in the yellow truck
00:00:40.070 --> 00:00:44.540
would observe the blue traveling
at five miles per hour.
00:00:44.540 --> 00:00:47.180
How could the person
on the side of the road
00:00:47.180 --> 00:00:50.350
see the blue car traveling
at 45 miles per hour
00:00:50.350 --> 00:00:52.004
and a person in the yellow truck
00:00:52.004 --> 00:00:55.500
see the blue car moving
at five miles per hour?
00:00:55.500 --> 00:00:57.330
This is because both observers
00:00:57.330 --> 00:01:00.230
are using different frames of reference.
00:01:00.230 --> 00:01:02.010
So let's go ahead and take a look at that,
00:01:02.010 --> 00:01:04.580
starting with the speed of the blue car.
00:01:04.580 --> 00:01:06.480
The person on the side of the road
00:01:06.480 --> 00:01:09.720
is using their frame of
reference of being at rest.
00:01:09.720 --> 00:01:12.710
So relative to them,
the blue car is moving
00:01:12.710 --> 00:01:15.060
at 45 miles per hour.
00:01:15.060 --> 00:01:17.140
To the person in this yellow truck,
00:01:17.140 --> 00:01:20.540
which remember is already
going 40 miles per hour,
00:01:20.540 --> 00:01:23.433
the blue car is going five miles per hour.
00:01:24.470 --> 00:01:26.990
Now let's do the exact same thing
00:01:26.990 --> 00:01:29.550
for the speed of the yellow truck.
00:01:29.550 --> 00:01:31.900
So what is the speed of the yellow truck
00:01:31.900 --> 00:01:34.510
for the observer on the side of the road?
00:01:34.510 --> 00:01:35.833
It's 40 miles per hour.
00:01:37.270 --> 00:01:39.520
And what do you think
the speed of the truck is
00:01:39.520 --> 00:01:43.203
for the person using their blue
car as the reference frame?
00:01:44.570 --> 00:01:47.890
Well, the blue car is
moving at 45 miles per hour,
00:01:47.890 --> 00:01:51.900
and the truck is only
moving at 40 miles per hour.
00:01:51.900 --> 00:01:54.120
So the speed of the yellow truck
00:01:54.120 --> 00:01:56.580
is actually five miles per hour slower
00:01:56.580 --> 00:01:59.340
than this reference frame,
because the blue car
00:01:59.340 --> 00:02:01.583
is already moving at 45 miles per hour.
00:02:02.570 --> 00:02:05.627
Now you might be thinking, "But wait,
00:02:05.627 --> 00:02:08.897
"the person on the side of
the road isn't really at rest.
00:02:08.897 --> 00:02:12.330
"They're on the earth
and the earth is moving."
00:02:12.330 --> 00:02:14.400
You're completely correct.
00:02:14.400 --> 00:02:17.670
The person is at rest
with respect to the earth.
00:02:17.670 --> 00:02:20.500
And the earth is the most
common frame of reference
00:02:20.500 --> 00:02:22.260
that we use.
00:02:22.260 --> 00:02:26.460
To an observer in space who is
not rotating with the earth,
00:02:26.460 --> 00:02:29.830
the blue car is going 45 miles per hour,
00:02:29.830 --> 00:02:33.740
plus the speed of Earth's rotation.
00:02:33.740 --> 00:02:36.510
And this is why a frame of
reference is so important.
00:02:36.510 --> 00:02:38.280
We just talked about one blue car
00:02:38.280 --> 00:02:40.490
having three different velocities
00:02:40.490 --> 00:02:43.160
depending what the frame of reference is.
00:02:43.160 --> 00:02:46.290
How would we communicate
this to avoid confusion?
00:02:46.290 --> 00:02:49.470
Well, we state the
reference frame we're using.
00:02:49.470 --> 00:02:52.970
The blue car is moving
at five miles per hour
00:02:52.970 --> 00:02:57.970
with respect to, which I'll
write as WRT, the yellow truck.
00:02:58.480 --> 00:03:00.300
This tells us that the yellow truck
00:03:00.300 --> 00:03:02.230
is our frame of reference.
00:03:02.230 --> 00:03:05.290
Or we could say that the yellow truck
00:03:05.290 --> 00:03:09.080
is moving at 40 miles
per hour and the blue car
00:03:09.080 --> 00:03:12.483
at 45 miles per hour,
with respect to the earth.
00:03:13.390 --> 00:03:16.140
That way everyone is on the same page,
00:03:16.140 --> 00:03:20.210
a page which, to be clear, is
in a book that relative to me
00:03:20.210 --> 00:03:21.043
is at rest.
|
Units | https://www.youtube.com/watch?v=ID-ny-NOdxg | vtt | https://www.youtube.com/api/timedtext?v=ID-ny-NOdxg&ei=wFWUZbLoK4y-mLAPnMankAM&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245296&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=E422EF87AE17D895C5351586781FD54F1C34B89E.B9E9EDD43DFF9AECB02966900C97E6BF8E3D8252&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.310 --> 00:00:02.010
- [Illustrator] Did you
know that communication
00:00:02.010 --> 00:00:05.640
is actually one of the most
important things in science?
00:00:05.640 --> 00:00:07.420
As we discover cool things,
00:00:07.420 --> 00:00:09.130
we need to be able to
share them with others.
00:00:09.130 --> 00:00:11.700
And when we're talking
about data and measurements
00:00:11.700 --> 00:00:13.270
with other scientists,
00:00:13.270 --> 00:00:15.820
we need to make sure
we're on the same page.
00:00:15.820 --> 00:00:18.120
So how do we do that?
00:00:18.120 --> 00:00:21.460
Well, one of the ways is to use units.
00:00:21.460 --> 00:00:25.750
We use units whenever we talk
about things like position,
00:00:25.750 --> 00:00:30.080
where an object is located,
how long it is, it's mass,
00:00:30.080 --> 00:00:33.800
how much matter it's made
up of or it's motion.
00:00:33.800 --> 00:00:35.173
How is that object moving?
00:00:36.300 --> 00:00:38.713
You probably hear units every day.
00:00:40.040 --> 00:00:42.290
For example, you've grown,
00:00:42.290 --> 00:00:45.410
let's say an inch and a
half in the past year,
00:00:45.410 --> 00:00:50.410
or that tree over there is 25 feet tall.
00:00:51.040 --> 00:00:55.480
And maybe you went swimming
in a 25 meter pool.
00:00:55.480 --> 00:00:59.190
And we're just gonna pretend
that the pool is a rectangle
00:00:59.190 --> 00:01:01.480
because as you can tell from my tree,
00:01:01.480 --> 00:01:03.463
my artistic skills are not that great.
00:01:04.340 --> 00:01:07.410
Anyway, this brings up
a super important point
00:01:07.410 --> 00:01:09.510
about why we use units.
00:01:09.510 --> 00:01:12.650
I just used three examples
of length measurements
00:01:12.650 --> 00:01:17.650
with three different units,
inches, feet, and meters.
00:01:17.780 --> 00:01:19.720
Imagine if I didn't attach a unit
00:01:19.720 --> 00:01:21.250
to any of these measurements,
00:01:21.250 --> 00:01:25.320
you grew one and a half, what? Meters?
00:01:25.320 --> 00:01:29.010
Whoa, one and a half hands.
00:01:29.010 --> 00:01:31.670
Well, whose hands?
00:01:31.670 --> 00:01:36.010
Your hands or my hands?
00:01:36.010 --> 00:01:39.420
Woof, well, pretend those are hands.
00:01:39.420 --> 00:01:44.010
Units let us know how much
of a quantity there is.
00:01:44.010 --> 00:01:47.620
So a meter is always
used to measure length
00:01:47.620 --> 00:01:50.580
and we know exactly how long a meter is.
00:01:50.580 --> 00:01:53.750
That way when we say
something is two meters long,
00:01:53.750 --> 00:01:56.760
no one has to guess at how big that is.
00:01:56.760 --> 00:02:00.030
Any measurement or data point
always needs to have a unit
00:02:00.030 --> 00:02:02.170
or else it's just a meaningless number.
00:02:02.170 --> 00:02:04.080
To avoid any confusion,
00:02:04.080 --> 00:02:07.890
in science we use what
are called SI units.
00:02:07.890 --> 00:02:11.720
SI units are the International System.
00:02:11.720 --> 00:02:16.070
Could there be any more
letters in this word system
00:02:16.070 --> 00:02:19.530
used by scientists all over the world.
00:02:19.530 --> 00:02:23.620
We'll use meters to
describe position or length,
00:02:23.620 --> 00:02:25.780
kilograms for mass,
00:02:25.780 --> 00:02:28.630
and if we're talking about
the motion of something,
00:02:28.630 --> 00:02:29.683
meters per second.
00:02:30.990 --> 00:02:35.260
And while this is the agreed
upon scientific unit system,
00:02:35.260 --> 00:02:39.470
you should be aware that
other systems do exist,
00:02:39.470 --> 00:02:43.060
which means things can very
easily get very confusing
00:02:43.060 --> 00:02:44.960
if you forget your units.
00:02:44.960 --> 00:02:46.107
And you might be thinking,
00:02:46.107 --> 00:02:49.690
"Oh, come on, who mixes up units?'
00:02:49.690 --> 00:02:52.910
Well, it happens more
often than you think,
00:02:52.910 --> 00:02:55.500
even rocket scientists have done it.
00:02:55.500 --> 00:02:58.430
I mean, a Mars Orbiter actually crashed
00:02:58.430 --> 00:03:00.830
due to a mix up in units.
00:03:00.830 --> 00:03:03.410
Now seriously, that actually happened,
00:03:03.410 --> 00:03:07.933
look it up and remember to use your units.
|
Meaning of absolute value | https://www.youtube.com/watch?v=zpln5ExhkyI | vtt | https://www.youtube.com/api/timedtext?v=zpln5ExhkyI&ei=wFWUZbTRDPu5vdIPkuqDsAk&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245296&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=C31249FBA98CADD0AB1B3D74318BBC4EBBF069B7.71499D72F7F4DAD772A2ABC704A2FCB616358DED&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.300 --> 00:00:01.133
- [Instructor] In this video,
00:00:01.133 --> 00:00:02.190
we're going to introduce ourselves
00:00:02.190 --> 00:00:04.230
to the idea of absolute value,
00:00:04.230 --> 00:00:09.100
which you can view as,
how far are you from zero?
00:00:09.100 --> 00:00:10.970
So for example,
00:00:10.970 --> 00:00:14.270
let's say that we have a bunch
of people living on a street.
00:00:14.270 --> 00:00:19.270
And let's say that we say
that the school is at zero,
00:00:19.320 --> 00:00:22.030
and we could think
about other people live.
00:00:22.030 --> 00:00:25.000
So let's say I live three miles
00:00:25.000 --> 00:00:27.920
to the right of the
school, maybe that's east.
00:00:27.920 --> 00:00:30.600
So this is where I live.
00:00:30.600 --> 00:00:33.190
So that's me right over here.
00:00:33.190 --> 00:00:37.800
And that you live three miles
to the left of the school.
00:00:37.800 --> 00:00:41.237
So this is where you would
be, three miles to the left.
00:00:41.237 --> 00:00:44.370
Or maybe we could say that's
to the west of the school.
00:00:44.370 --> 00:00:46.660
Now you could say that your position
00:00:46.660 --> 00:00:50.270
is at negative three miles
relative to the school.
00:00:50.270 --> 00:00:52.810
And my position is at positive three miles
00:00:52.810 --> 00:00:54.290
relative to the school.
00:00:54.290 --> 00:00:55.680
But what we might care about
00:00:55.680 --> 00:00:58.770
is just how far are we from the school?
00:00:58.770 --> 00:01:00.060
And so there, you could say,
00:01:00.060 --> 00:01:03.760
well, we're each exactly
three miles from the school.
00:01:03.760 --> 00:01:05.800
You're three miles from the school,
00:01:05.800 --> 00:01:08.520
and I am three miles from the school.
00:01:08.520 --> 00:01:12.460
And that's what absolute value
is actually trying to get at.
00:01:12.460 --> 00:01:16.840
So for example, your
position is negative three,
00:01:16.840 --> 00:01:19.730
but if we were to take the absolute value,
00:01:19.730 --> 00:01:23.730
which you denote by these
two straight up down bars
00:01:23.730 --> 00:01:25.490
around the number, then we say,
00:01:25.490 --> 00:01:28.380
that's just going to be
your distance from zero,
00:01:28.380 --> 00:01:31.100
which is just going to be three miles.
00:01:31.100 --> 00:01:31.933
Similarly,
00:01:33.360 --> 00:01:36.890
my position is at three
miles, positive three miles.
00:01:36.890 --> 00:01:39.290
The absolute value of that is going to be,
00:01:39.290 --> 00:01:40.910
drum roll, please.
00:01:40.910 --> 00:01:43.500
It is going to be three as well.
00:01:43.500 --> 00:01:45.020
You might already see a pattern.
00:01:45.020 --> 00:01:47.530
If you're taking an absolute
value of a negative number,
00:01:47.530 --> 00:01:49.950
you get the number without the negative.
00:01:49.950 --> 00:01:51.970
And if you take the absolute
value of a positive number,
00:01:51.970 --> 00:01:54.260
it just equals itself again.
00:01:54.260 --> 00:01:56.990
But the reason why that is the case
00:01:56.990 --> 00:01:58.000
is because we're just saying,
00:01:58.000 --> 00:02:01.370
how far is that thing from zero?
00:02:01.370 --> 00:02:03.430
Let me give you another example.
00:02:03.430 --> 00:02:08.430
Let's say that we have
some type of a cruise ship,
00:02:09.020 --> 00:02:11.550
and that's the water right over there.
00:02:11.550 --> 00:02:14.590
This is the cruise ship.
00:02:14.590 --> 00:02:16.000
Let me draw it.
00:02:16.000 --> 00:02:18.880
It's this big cruise
ship, nice and big one,
00:02:18.880 --> 00:02:20.790
has water slides on it, and whatever else,
00:02:20.790 --> 00:02:23.060
whatever you would expect
from a huge cruise ship.
00:02:23.060 --> 00:02:25.970
And let say, we think about the height
00:02:25.970 --> 00:02:28.020
of where the different
floors are in the ship.
00:02:28.020 --> 00:02:29.680
And a natural place to think about
00:02:29.680 --> 00:02:32.890
is based on where the sea level is.
00:02:32.890 --> 00:02:35.770
So we call that height zero.
00:02:35.770 --> 00:02:40.770
Now there's this big waterfall
pool type thing up here.
00:02:40.900 --> 00:02:44.250
Let's just say, it's a pool
for simplicity, on the roof.
00:02:44.250 --> 00:02:49.250
And let's say that that is
at an altitude of 80 feet.
00:02:49.610 --> 00:02:53.620
So we would call that at positive 80 feet.
00:02:53.620 --> 00:02:56.880
And let's say the engine
room is right over here.
00:02:56.880 --> 00:02:58.550
And if you wanted to know its position,
00:02:58.550 --> 00:03:02.040
its height, well, it is
going to be below zero,
00:03:02.040 --> 00:03:06.443
it's below sea level, let's
say it's at negative 20 feet.
00:03:07.290 --> 00:03:09.340
So that would give you its position.
00:03:09.340 --> 00:03:11.960
One is 80 feet above the sea level,
00:03:11.960 --> 00:03:14.600
and then one is 20 feet
below the sea level.
00:03:14.600 --> 00:03:17.260
But if you just wanted
to know how far they are,
00:03:17.260 --> 00:03:18.930
well, you could take the absolute value.
00:03:18.930 --> 00:03:21.720
How far is that roof deck pool?
00:03:21.720 --> 00:03:24.040
Well, you take the absolute value of 80.
00:03:24.040 --> 00:03:26.610
You are going to get 80.
00:03:26.610 --> 00:03:30.650
How far is that engine room from zero?
00:03:30.650 --> 00:03:33.030
How far is it from sea level?
00:03:33.030 --> 00:03:36.773
Well, the absolute value of
negative 20 is going to be 20.
|
Compare rational numbers using a number line | https://www.youtube.com/watch?v=6h0Wi8Dcd0E | vtt | https://www.youtube.com/api/timedtext?v=6h0Wi8Dcd0E&ei=wFWUZavVGoudhcIPh-amwAQ&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245296&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=8EDDB4C319AA09AEFBE94935073A3ED07C8C9A9F.D9B2E3C97107563C7B6ED2F9D8F31574D4291255&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.300 --> 00:00:01.690
- [Sal] What we're gonna do in this video
00:00:01.690 --> 00:00:04.040
is get some practice comparing numbers,
00:00:04.040 --> 00:00:07.640
especially positive and negative numbers.
00:00:07.640 --> 00:00:10.250
So for each of these pairs of numbers,
00:00:10.250 --> 00:00:13.330
I want you to either
write a less than sign
00:00:13.330 --> 00:00:14.760
or a greater than sign,
00:00:14.760 --> 00:00:16.580
or just think about which of these two
00:00:16.580 --> 00:00:18.880
is greater than the other.
00:00:18.880 --> 00:00:20.440
Pause this video and see if you can work
00:00:20.440 --> 00:00:22.003
through these four pairs.
00:00:22.920 --> 00:00:26.200
All right, now let's do it together.
00:00:26.200 --> 00:00:30.110
So let's first compare -7/4 to -3/4.
00:00:30.110 --> 00:00:31.450
And I'm going to try to do that
00:00:31.450 --> 00:00:34.890
by visualizing them on a number line.
00:00:34.890 --> 00:00:37.390
So let me draw a straighter line.
00:00:37.390 --> 00:00:38.950
There we go.
00:00:38.950 --> 00:00:40.530
Let's see, they're both negative,
00:00:40.530 --> 00:00:42.310
which means both to the left of zero.
00:00:42.310 --> 00:00:44.270
So I'll focus on the left of zero.
00:00:44.270 --> 00:00:46.640
So that's zero.
00:00:46.640 --> 00:00:47.473
And let's see,
00:00:47.473 --> 00:00:48.630
they're both given in fourths
00:00:48.630 --> 00:00:51.260
and we need to go all the way to 7/4,
00:00:51.260 --> 00:00:52.340
less than zero.
00:00:52.340 --> 00:00:54.970
So let me think of each
of these as a fourth.
00:00:54.970 --> 00:00:58.920
So one, two, three, four.
00:00:58.920 --> 00:01:01.010
That would be -1.
00:01:01.010 --> 00:01:05.020
One, two, three, four.
00:01:05.020 --> 00:01:07.200
That would be -2 and that's enough for us,
00:01:07.200 --> 00:01:09.170
but I could keep going if I liked.
00:01:09.170 --> 00:01:13.790
Now, where is -7/4 on this number line?
00:01:13.790 --> 00:01:15.670
Well, I just said each
of these is a fourth,
00:01:15.670 --> 00:01:19.590
so negative 1/4, 2/4, 3/4,
00:01:19.590 --> 00:01:23.700
4/4, 5/4, 6/4, 7/4.
00:01:23.700 --> 00:01:26.023
So this right over here is -7/4.
00:01:28.720 --> 00:01:32.082
And where is negative
-3/4 on the number line?
00:01:32.082 --> 00:01:36.373
- 1/4, -2/4, -3/4.
00:01:37.850 --> 00:01:39.670
So which one is greater?
00:01:39.670 --> 00:01:42.240
Well, we can see that -3/4
00:01:42.240 --> 00:01:46.580
is to the right of -7/4.
00:01:46.580 --> 00:01:51.580
So -3/4 is greater or that
-7/4 is less than -3/4.
00:01:53.010 --> 00:01:55.700
So I'll put a less than right over here.
00:01:55.700 --> 00:01:57.110
Let's do this next example.
00:01:57.110 --> 00:01:58.860
We're going to compare 0.6 to -1.8.
00:02:00.524 --> 00:02:02.270
If you haven't already given it a shot
00:02:02.270 --> 00:02:05.120
or if this previous example
helped inspire something
00:02:05.120 --> 00:02:06.430
and you give it another shot,
00:02:06.430 --> 00:02:08.640
and then we'll do it together.
00:02:08.640 --> 00:02:11.493
So let's draw a number line again.
00:02:12.480 --> 00:02:17.480
And let me put zero right over here.
00:02:18.950 --> 00:02:20.620
That's 1.
00:02:20.620 --> 00:02:22.340
That's 2.
00:02:22.340 --> 00:02:24.700
This is -1.
00:02:24.700 --> 00:02:27.000
This is -2.
00:02:27.000 --> 00:02:29.500
And actually let me make half marks here,
00:02:29.500 --> 00:02:32.140
so we can get a little
bit closer to thinking
00:02:32.140 --> 00:02:35.440
about where these two numbers
sit on the number line.
00:02:35.440 --> 00:02:37.233
I'll start with 0.6.
00:02:38.440 --> 00:02:41.460
0.6 is you could view that as 6/10.
00:02:41.460 --> 00:02:42.990
It's a little bit more than 5/10.
00:02:42.990 --> 00:02:44.520
It's a little bit more than 1/2.
00:02:44.520 --> 00:02:47.220
So 0.6 is gonna be
roughly right around here
00:02:47.220 --> 00:02:49.053
on our number line, 0.6.
00:02:50.230 --> 00:02:51.193
And where is -1.8?
00:02:53.230 --> 00:02:54.100
Well, it's negative.
00:02:54.100 --> 00:02:56.030
So it's going to be to the left of zero,
00:02:56.030 --> 00:02:58.220
and we're gonna go 1.8 to the left.
00:02:58.220 --> 00:02:59.950
So this is -1.
00:02:59.950 --> 00:03:02.090
This is -2, that's too far.
00:03:02.090 --> 00:03:03.660
This is -1.5.
00:03:03.660 --> 00:03:07.230
- 1.8 is going to be roughly,
00:03:07.230 --> 00:03:09.460
let me do this in this
color, right over here.
00:03:09.460 --> 00:03:12.063
It's going to be roughly
right over there, -1.8.
00:03:13.600 --> 00:03:16.173
And so you can see that it is left of 0.6
00:03:17.401 --> 00:03:18.742
on our number line.
00:03:18.742 --> 00:03:21.667
And so -1.8 is less than 0.6,
00:03:21.667 --> 00:03:24.000
or 0.6 is greater than -1.8.
00:03:26.900 --> 00:03:28.280
Let's do more examples here.
00:03:28.280 --> 00:03:30.670
Let's compare these two numbers.
00:03:30.670 --> 00:03:31.503
Well, once again,
00:03:31.503 --> 00:03:33.070
let me put them on a number line.
00:03:33.070 --> 00:03:34.300
And I wanna show you that the number line
00:03:34.300 --> 00:03:35.390
does not have to go left-right.
00:03:35.390 --> 00:03:37.260
It could go up-down.
00:03:37.260 --> 00:03:38.780
So let's try that.
00:03:38.780 --> 00:03:40.700
And I'll do it in a different color.
00:03:40.700 --> 00:03:44.480
So I'll make a line like this.
00:03:44.480 --> 00:03:48.160
And I am going to have,
00:03:48.160 --> 00:03:52.200
let's call this zero right over here.
00:03:52.200 --> 00:03:53.820
And so this is 1.
00:03:53.820 --> 00:03:55.990
This is 2.
00:03:55.990 --> 00:03:58.570
This is -1.
00:03:58.570 --> 00:04:01.600
This is -2.
00:04:01.600 --> 00:04:05.430
Now, where is 2 1/5 on the number line?
00:04:05.430 --> 00:04:08.980
So that is positive 1, positive 2.
00:04:08.980 --> 00:04:11.020
And then we're going to go about a fifth.
00:04:11.020 --> 00:04:14.710
So that'll get us
roughly right over there.
00:04:14.710 --> 00:04:18.790
And then where is -1 1/10?
00:04:18.790 --> 00:04:21.875
Well, we're not gonna
go below zero, so -1.
00:04:21.875 --> 00:04:25.270
And we're gonna go another
1/10 beyond that below zero.
00:04:25.270 --> 00:04:28.030
So it's gonna be roughly around there.
00:04:28.030 --> 00:04:31.070
So that is -1 1/10.
00:04:31.070 --> 00:04:36.070
And so we can see that -1 1/10
is less than positive 2 1/5,
00:04:36.830 --> 00:04:41.830
or positive 2 1/5 is greater than -1 1/10.
00:04:42.880 --> 00:04:46.850
Let's do one last example,
comparing these two numbers here.
00:04:46.850 --> 00:04:51.160
And actually, I can extend this
number line right over here,
00:04:51.160 --> 00:04:54.410
and I should be able to
fit both of these numbers.
00:04:54.410 --> 00:04:56.050
So let me try to do that.
00:04:56.050 --> 00:04:57.920
So I'm going to extend it.
00:04:57.920 --> 00:05:01.490
This is -3 right over here.
00:05:01.490 --> 00:05:03.167
So where would -1.5 sit?
00:05:04.700 --> 00:05:07.554
Well, we're going below
zero so that's a -1.
00:05:07.554 --> 00:05:09.920
- 1.5 would be another half,
00:05:09.920 --> 00:05:11.999
it'd be right in between -1 and -2.
00:05:11.999 --> 00:05:16.600
So -1.5 is right over there.
00:05:16.600 --> 00:05:19.230
And where would -2.5 be?
00:05:19.230 --> 00:05:22.860
Well, we go -1, -2, and then another half.
00:05:22.860 --> 00:05:25.073
So this right over here is -2.5.
00:05:27.650 --> 00:05:29.630
And we could see very clearly that -1.5
00:05:31.210 --> 00:05:32.800
is higher than -2.5,
00:05:34.010 --> 00:05:37.260
so it is also greater.
00:05:37.260 --> 00:05:38.173
And we're done.
|
Introduction to negative numbers | https://www.youtube.com/watch?v=u8UKdNdpkh4 | vtt | https://www.youtube.com/api/timedtext?v=u8UKdNdpkh4&ei=wFWUZfjTFYmYvdIPk4G6aA&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245296&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=5934A974EBA6C569483A4423DE11F9C225EBFDDA.9AC6660310D25739D1F272B0BAAE7B6E01D72812&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.860 --> 00:00:03.150
- [Instructor] In this video,
we're gonna introduce ourself
00:00:03.150 --> 00:00:06.560
to the idea of negative numbers.
00:00:06.560 --> 00:00:10.210
Now you're already used to
the idea of positive numbers.
00:00:10.210 --> 00:00:13.280
You just call them numbers, not
positive (chuckles) numbers.
00:00:13.280 --> 00:00:14.810
And just to give you an example,
00:00:14.810 --> 00:00:16.620
I will draw a number line here.
00:00:16.620 --> 00:00:19.550
And this should all be review for you,
00:00:19.550 --> 00:00:23.160
so let me start at zero,
00:00:23.160 --> 00:00:25.760
and then this would be one.
00:00:25.760 --> 00:00:27.510
This would be two.
00:00:27.510 --> 00:00:29.490
This would be three.
00:00:29.490 --> 00:00:32.530
And you can think of these
numbers, which you're used to,
00:00:32.530 --> 00:00:34.650
which we could call positive numbers,
00:00:34.650 --> 00:00:37.460
as how far we are above zero.
00:00:37.460 --> 00:00:41.650
One is one above zero.
Two is two above zero.
00:00:41.650 --> 00:00:43.920
Now what do you think negative
numbers are going to be?
00:00:43.920 --> 00:00:47.970
If positive numbers are
how far we are above zero,
00:00:47.970 --> 00:00:52.250
then a negative number would
be how far are we below zero.
00:00:52.250 --> 00:00:56.460
So for example, if I go one to
the left on this number line,
00:00:56.460 --> 00:00:59.240
that would now get us to negative one.
00:00:59.240 --> 00:01:01.320
Positive one is one to the right.
00:01:01.320 --> 00:01:03.610
Negative one is one to the left.
00:01:03.610 --> 00:01:05.930
If I were to go another one to the left,
00:01:05.930 --> 00:01:09.920
I would get to negative
two, and I could keep going.
00:01:09.920 --> 00:01:12.030
As many positive numbers there are,
00:01:12.030 --> 00:01:14.040
I can have the negative version of it.
00:01:14.040 --> 00:01:15.620
However far I am to the right,
00:01:15.620 --> 00:01:18.770
I could be that far to the left.
00:01:18.770 --> 00:01:19.730
Now some of you,
00:01:19.730 --> 00:01:22.550
especially if you live in
very cold parts of the world,
00:01:22.550 --> 00:01:24.970
might have already
experienced negative numbers
00:01:24.970 --> 00:01:26.420
in some way.
00:01:26.420 --> 00:01:29.930
For example, if you look at a thermometer,
00:01:29.930 --> 00:01:33.400
this has both a Celsius
thermometer, right over here,
00:01:33.400 --> 00:01:34.870
and Fahrenheit.
00:01:34.870 --> 00:01:37.970
We know that you can get temperatures
00:01:37.970 --> 00:01:41.050
below zero degrees Celsius
00:01:41.050 --> 00:01:43.810
and temperatures below
zero degrees Fahrenheit.
00:01:43.810 --> 00:01:46.140
On this thermometer, they just mark
00:01:46.140 --> 00:01:49.340
how far we are below zero
with these red numbers,
00:01:49.340 --> 00:01:51.490
but really these are negative numbers.
00:01:51.490 --> 00:01:53.650
And we specify negative numbers
00:01:53.650 --> 00:01:57.700
by putting that negative
sign right in front of it
00:01:57.700 --> 00:01:59.070
like that.
00:01:59.070 --> 00:02:02.300
So for example, 20 degrees Celsius
00:02:02.300 --> 00:02:04.640
is positive of 20 degrees Celsius
00:02:04.640 --> 00:02:07.640
is actually a pretty
comfortable temperature,
00:02:07.640 --> 00:02:11.890
but negative 20 degrees
Celsius, that is below,
00:02:11.890 --> 00:02:15.350
20 degrees Celsius below
the freezing point of water,
00:02:15.350 --> 00:02:19.430
that is a very, very, very,
very cold temperature.
00:02:19.430 --> 00:02:21.840
One is 20 degrees above zero.
00:02:21.840 --> 00:02:25.650
One is 20 degrees below zero.
00:02:25.650 --> 00:02:28.440
So a big picture, for any given number,
00:02:28.440 --> 00:02:30.030
there's a negative version of it.
00:02:30.030 --> 00:02:33.080
For example, this right over
here would be positive six,
00:02:33.080 --> 00:02:35.700
and then you could have negative six.
00:02:35.700 --> 00:02:38.900
But negative six is six below zero
00:02:38.900 --> 00:02:42.060
or six left of the zero
on the number line,
00:02:42.060 --> 00:02:46.240
while positive six is, of
course, six above zero.
00:02:46.240 --> 00:02:48.540
So I will leave you there.
00:02:48.540 --> 00:02:49.373
You might be thinking,
00:02:49.373 --> 00:02:52.090
"Oh wow, this looks a lot
like a subtraction sign.
00:02:52.090 --> 00:02:54.360
Maybe it is related to
subtraction somehow."
00:02:54.360 --> 00:02:57.200
Or "How can I do addition and subtraction,
00:02:57.200 --> 00:02:59.750
multiplication and division
with negative numbers?"
00:02:59.750 --> 00:03:03.083
And for that we will go to future videos.
|
Seasons | https://www.youtube.com/watch?v=0r9Lc7oYq5M | vtt | https://www.youtube.com/api/timedtext?v=0r9Lc7oYq5M&ei=wFWUZdfGGKa9mLAP6MiQ0AY&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245296&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=EC0AC31D76977C51D9908503580450839DF62929.73A1AA2FB57E2F48C0403CA900AEB1CDB36D6FE5&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.260 --> 00:00:01.850
- [Instructor] In this video,
we're gonna think about
00:00:01.850 --> 00:00:04.230
why we have seasons on Earth,
00:00:04.230 --> 00:00:08.340
like summer and fall
and winter and spring.
00:00:08.340 --> 00:00:10.530
Now, one theory that some folks might have
00:00:10.530 --> 00:00:12.150
is maybe it's due to the distance
00:00:12.150 --> 00:00:13.550
between the Earth and the sun.
00:00:13.550 --> 00:00:16.210
We know that the Earth orbits the sun,
00:00:16.210 --> 00:00:19.170
the sun is where the
great majority of the heat
00:00:19.170 --> 00:00:22.100
and the energy on the surface
of the Earth comes from.
00:00:22.100 --> 00:00:23.670
And maybe it's the case
00:00:23.670 --> 00:00:25.630
that there's certain times of year
00:00:25.630 --> 00:00:27.580
when we are further from the sun,
00:00:27.580 --> 00:00:29.320
and there's other times of year
00:00:29.320 --> 00:00:32.490
when we are closer to the sun.
00:00:32.490 --> 00:00:36.050
Well, this doesn't actually
hold up to why we have seasons
00:00:36.050 --> 00:00:38.840
because first of all, when
the Northern Hemisphere
00:00:38.840 --> 00:00:41.060
the top half of Earth has winter,
00:00:41.060 --> 00:00:44.090
the bottom hemisphere has
summer and vice versa.
00:00:44.090 --> 00:00:46.820
So it can't just be due to the
distance of the whole planet,
00:00:46.820 --> 00:00:48.270
it also turns out
00:00:48.270 --> 00:00:53.200
that when Earth is furthest
from the sun is in July,
00:00:53.200 --> 00:00:55.710
which is in the middle of summer
00:00:55.710 --> 00:00:57.600
in the Northern Hemisphere,
00:00:57.600 --> 00:00:59.580
and when we are closest to the sun
00:00:59.580 --> 00:01:01.660
is actually in January
00:01:01.660 --> 00:01:04.540
which we know tends to
be our colder season
00:01:04.540 --> 00:01:06.040
in the Northern Hemisphere.
00:01:06.040 --> 00:01:08.780
So distance to the sun does not hold up
00:01:08.780 --> 00:01:11.200
as to why we have seasons.
00:01:11.200 --> 00:01:14.030
The real reason why we have seasons
00:01:14.030 --> 00:01:16.840
is because of Earth's axial tilt,
00:01:16.840 --> 00:01:19.500
I guess you could say that
or it's rotational tilt.
00:01:19.500 --> 00:01:21.630
Now this picture shows that tilt
00:01:21.630 --> 00:01:23.940
but before we go into it,
I'd like to remind folks
00:01:23.940 --> 00:01:27.030
that this is nowhere near drawn at scale.
00:01:27.030 --> 00:01:30.800
The actual sun has a diameter
over 100 times out of Earth,
00:01:30.800 --> 00:01:32.950
a million Earths can fit in the sun
00:01:32.950 --> 00:01:36.210
and the actual distance
between the Earth and the sun
00:01:36.210 --> 00:01:40.160
is over 100 times the diameter
between the sun and Earth.
00:01:40.160 --> 00:01:41.700
But going back to tilt
00:01:41.700 --> 00:01:44.680
and you could see that
here in this picture,
00:01:44.680 --> 00:01:48.430
Earth's north pole does
not point straight up
00:01:48.430 --> 00:01:52.340
from the plane of Earth's
orbit around the sun.
00:01:52.340 --> 00:01:55.560
What do I mean by the plane of
Earth's orbit around the sun?
00:01:55.560 --> 00:01:58.160
This red circle that you see,
00:01:58.160 --> 00:01:59.920
or this ellipse that you see,
00:01:59.920 --> 00:02:02.440
if you imagine that being on a surface
00:02:02.440 --> 00:02:04.330
of a table or a plane,
00:02:04.330 --> 00:02:06.010
that would be our orbital plane.
00:02:06.010 --> 00:02:07.810
And we can see that the north pole
00:02:07.810 --> 00:02:09.530
does not go straight up from that
00:02:09.530 --> 00:02:11.720
and the south pole does
not go straight down,
00:02:11.720 --> 00:02:13.370
that actually we're looking
00:02:13.370 --> 00:02:17.620
at an angle of about 23.5 degrees.
00:02:17.620 --> 00:02:21.120
And that's the reason
why we have the seasons.
00:02:21.120 --> 00:02:23.290
To understand why that is the case,
00:02:23.290 --> 00:02:25.510
let's imagine Earth when
the Northern Hemisphere
00:02:25.510 --> 00:02:27.330
is most pointed towards the sun,
00:02:27.330 --> 00:02:29.310
which happens in late June.
00:02:29.310 --> 00:02:30.490
And so let me draw the equator
00:02:30.490 --> 00:02:32.630
to help us visualize this a little bit
00:02:32.630 --> 00:02:34.210
and let's compare that
00:02:34.210 --> 00:02:35.800
to when the Northern Hemisphere
00:02:35.800 --> 00:02:37.630
is most pointed away from the sun,
00:02:37.630 --> 00:02:39.650
which happens in late December.
00:02:39.650 --> 00:02:42.340
And so I will draw the equator again
00:02:42.340 --> 00:02:46.400
to help us visualize this.
00:02:46.400 --> 00:02:50.250
And let's pick a similar point
in the Northern Hemisphere.
00:02:50.250 --> 00:02:53.550
So let's pick a point that's a
little bit above the equator.
00:02:53.550 --> 00:02:54.920
So let's say that point
00:02:54.920 --> 00:02:58.410
and a comparable point in this scenario
00:02:58.410 --> 00:03:01.060
is going to be right over here.
00:03:01.060 --> 00:03:04.480
It's about that same
distance above the equator.
00:03:04.480 --> 00:03:08.240
Notice, in late June in
the Northern Hemisphere
00:03:08.240 --> 00:03:10.700
the sun is almost directly above
00:03:10.700 --> 00:03:12.910
this white point that we're seeing here.
00:03:12.910 --> 00:03:16.300
While in this scenario,
the sun is at an angle.
00:03:16.300 --> 00:03:18.700
The surface of the
Earth is more like this,
00:03:18.700 --> 00:03:22.420
so the sun's rays are coming at an angle.
00:03:22.420 --> 00:03:24.050
And if you think about it,
00:03:24.050 --> 00:03:25.050
think about the scenario,
00:03:25.050 --> 00:03:26.580
the difference between when the sun
00:03:26.580 --> 00:03:28.870
is directly bearing down on something,
00:03:28.870 --> 00:03:30.650
versus when it is coming at an angle.
00:03:30.650 --> 00:03:33.700
Let's say this is a side
view of two surfaces.
00:03:33.700 --> 00:03:36.870
And the surface on the right
has twice the surface area.
00:03:36.870 --> 00:03:38.900
You can see the side view
has twice the length,
00:03:38.900 --> 00:03:41.820
so the surface area if
you were to see it in 3D
00:03:41.820 --> 00:03:43.380
would be twice the surface area
00:03:43.380 --> 00:03:46.470
of what we have on the left here.
00:03:46.470 --> 00:03:48.400
But if you have the same amount of sun
00:03:48.400 --> 00:03:50.460
coming from the same direction,
00:03:50.460 --> 00:03:54.330
so here, let me just
draw three sun rays here,
00:03:54.330 --> 00:03:55.300
this is just indicative
00:03:55.300 --> 00:03:58.810
and let me draw three sun rays here.
00:03:58.810 --> 00:04:01.280
Notice you have this same amount of energy
00:04:01.280 --> 00:04:03.760
but here you're hitting
twice the surface area.
00:04:03.760 --> 00:04:06.360
So, the amount of energy
per unit surface area
00:04:06.360 --> 00:04:09.660
is gonna be half as much in this scenario
00:04:09.660 --> 00:04:11.840
where the sun is coming at an angle
00:04:11.840 --> 00:04:14.130
versus this scenario where the sunlight
00:04:14.130 --> 00:04:17.870
is coming more directly
on top of that point.
00:04:17.870 --> 00:04:19.970
And wherever you go in
the Northern Hemisphere
00:04:19.970 --> 00:04:22.590
the angle is less direct in the winter
00:04:22.590 --> 00:04:24.260
than it is in the summer.
00:04:24.260 --> 00:04:25.640
Now there's also some effects
00:04:25.640 --> 00:04:27.700
on the amount of daylight you get.
00:04:27.700 --> 00:04:29.610
For example, in the summer,
00:04:29.610 --> 00:04:30.810
when the Northern Hemisphere
00:04:30.810 --> 00:04:33.220
is most tilted towards the Earth,
00:04:33.220 --> 00:04:35.500
in the north pole, you're
gonna have constant daylight
00:04:35.500 --> 00:04:37.640
and the south pole you're
gonna have constant nighttime.
00:04:37.640 --> 00:04:38.940
And then the opposite happens
00:04:38.940 --> 00:04:41.370
when the Northern
Hemisphere is pointed away.
00:04:41.370 --> 00:04:43.530
And then when we think
about spring and autumn
00:04:43.530 --> 00:04:45.030
in either hemisphere,
00:04:45.030 --> 00:04:46.890
you can see that the
angle of Earth's rotation
00:04:46.890 --> 00:04:49.920
does not change from that 23.5 degrees,
00:04:49.920 --> 00:04:51.610
but in spring and autumn
00:04:51.610 --> 00:04:53.660
the Northern Hemisphere is not pointed
00:04:53.660 --> 00:04:55.360
to or away from the sun,
00:04:55.360 --> 00:04:57.500
it's kind of just pointed to the side.
00:04:57.500 --> 00:04:59.030
So in these two points,
00:04:59.030 --> 00:05:01.760
comparable points on the
Northern or Southern hemisphere
00:05:01.760 --> 00:05:05.723
are seeing similar angles
of the actual sunlight.
|
Comparing animal and plant cells | https://www.youtube.com/watch?v=HjC-eMiMDfo | vtt | https://www.youtube.com/api/timedtext?v=HjC-eMiMDfo&ei=wFWUZaXrLYToxN8P8vGaGA&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245296&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=50447746DB7BD9F463D9655010E5CE09226134C9.4A0A79107F872EFAE09EB014837BFAC05D7F06FF&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.190 --> 00:00:02.890
- [Instructor] So let's play
a game of Spot the Difference.
00:00:02.890 --> 00:00:04.700
Now, if you were asked
to spot the difference
00:00:04.700 --> 00:00:06.380
between these two pictures,
00:00:06.380 --> 00:00:09.060
you'd probably laugh and
say, "That's too easy."
00:00:09.060 --> 00:00:11.720
Because it's obvious that this
picture of a lion on the left
00:00:11.720 --> 00:00:14.020
is nowhere close to
looking like the picture
00:00:14.020 --> 00:00:16.090
of a green fern plant on the right.
00:00:16.090 --> 00:00:17.860
What's more, a lion and a fern
00:00:17.860 --> 00:00:19.680
not only look completely different,
00:00:19.680 --> 00:00:21.930
they also function differently.
00:00:21.930 --> 00:00:24.920
But what if I told you that
if we zoomed in really close
00:00:24.920 --> 00:00:27.610
and compared the lion's
cells with the fern's cells,
00:00:27.610 --> 00:00:30.240
they'd actually share many similarities?
00:00:30.240 --> 00:00:33.620
An animal cell and a plant cell
have several common features
00:00:33.620 --> 00:00:36.030
as well as a few key differences.
00:00:36.030 --> 00:00:39.000
In this video, we're going
to spot the similarities
00:00:39.000 --> 00:00:41.540
and the differences between
the two types of cells,
00:00:41.540 --> 00:00:44.440
and talk about their
functions inside the cells.
00:00:44.440 --> 00:00:47.290
So, first off, let's take
a look at some cell models.
00:00:47.290 --> 00:00:49.500
Here on the left is an animal cell,
00:00:49.500 --> 00:00:51.880
and on the right is a plant cell.
00:00:51.880 --> 00:00:53.970
First, let's try and identify the things
00:00:53.970 --> 00:00:57.110
that both animal and plant
cells share in common.
00:00:57.110 --> 00:00:59.530
If you recall, both animal and plant cells
00:00:59.530 --> 00:01:00.750
have a cell membrane,
00:01:00.750 --> 00:01:03.000
which acts like a gate
to control what enters
00:01:03.000 --> 00:01:04.420
and leaves the cell.
00:01:04.420 --> 00:01:05.870
Animal cells and plant cells
00:01:05.870 --> 00:01:09.320
also have this jelly-like
substance called the cytosol,
00:01:09.320 --> 00:01:11.720
which contains organelles
or small compartments
00:01:11.720 --> 00:01:14.410
with specific functions inside the cell.
00:01:14.410 --> 00:01:17.630
Animal and plant cells share
several common organelles,
00:01:17.630 --> 00:01:22.470
two of which include the
nucleus and the mitochondria.
00:01:22.470 --> 00:01:24.180
The nucleus within each cell type
00:01:24.180 --> 00:01:27.960
serves as an information database
to store the cell's genes,
00:01:27.960 --> 00:01:32.010
while the mitochondria act as
factories to break down sugars
00:01:32.010 --> 00:01:34.860
and release energy that the cells can use.
00:01:34.860 --> 00:01:37.030
So now that we've identified some features
00:01:37.030 --> 00:01:38.840
found in both kinds of cells,
00:01:38.840 --> 00:01:41.750
let's look closer to spot
the fundamental differences
00:01:41.750 --> 00:01:44.030
between animal and plant cells.
00:01:44.030 --> 00:01:45.610
As you can see in this diagram,
00:01:45.610 --> 00:01:48.070
plant cells have an
additional layer of material
00:01:48.070 --> 00:01:49.890
that surrounds the cell membrane.
00:01:49.890 --> 00:01:52.180
This is called a cell wall,
00:01:52.180 --> 00:01:55.390
which makes the plant cell
more structured and stiff.
00:01:55.390 --> 00:01:56.930
Think of a celery stalk
00:01:56.930 --> 00:02:00.020
compared to a raw piece
of chicken or fish.
00:02:00.020 --> 00:02:02.200
The animal muscle tissue is floppy
00:02:02.200 --> 00:02:04.300
while the celery stalk is firm.
00:02:04.300 --> 00:02:06.530
That's cell walls in action.
00:02:06.530 --> 00:02:08.810
Also, plant cells have
these special organelles
00:02:08.810 --> 00:02:11.380
called chloroplasts, which
are what give plants,
00:02:11.380 --> 00:02:14.150
like the fern we saw, their green color.
00:02:14.150 --> 00:02:16.380
Chloroplasts are the
site of photosynthesis,
00:02:16.380 --> 00:02:18.100
which is how plants make their own food
00:02:18.100 --> 00:02:19.680
in the form of sugars.
00:02:19.680 --> 00:02:22.670
If the word sugar rings a
bell, you're on the right track
00:02:22.670 --> 00:02:24.930
because I mentioned
earlier that mitochondria
00:02:24.930 --> 00:02:27.910
are responsible for breaking down sugars.
00:02:27.910 --> 00:02:30.550
In plant cells, chloroplasts
and mitochondria
00:02:30.550 --> 00:02:32.590
are like good buddies that help each other
00:02:32.590 --> 00:02:33.900
and work together.
00:02:33.900 --> 00:02:36.750
Chloroplasts make sugars
through photosynthesis
00:02:36.750 --> 00:02:39.380
and mitochondria convert
the sugars into energy
00:02:39.380 --> 00:02:42.110
that, ultimately, the plant can use.
00:02:42.110 --> 00:02:45.520
Both cell walls and chloroplasts
are found in plant cells
00:02:45.520 --> 00:02:48.760
but not animal cells, such
as the ones in you and me.
00:02:48.760 --> 00:02:52.570
And luckily for you and me,
this means we aren't green.
00:02:52.570 --> 00:02:55.720
In summary, we just identified
several similarities
00:02:55.720 --> 00:02:59.560
and differences in our comparison
of animal and plant cells.
00:02:59.560 --> 00:03:02.430
While both cell types
have a cell membrane,
00:03:02.430 --> 00:03:06.400
cytosol, a nucleus, and mitochondria,
00:03:06.400 --> 00:03:07.680
plant cells have a cell wall
00:03:07.680 --> 00:03:11.720
that makes them stiff and rigid,
think about celery stalks,
00:03:11.720 --> 00:03:13.240
and they have chloroplasts,
00:03:13.240 --> 00:03:16.750
which makes sugars and give
plants their green color.
00:03:16.750 --> 00:03:18.560
All of these are just a handful
00:03:18.560 --> 00:03:20.570
of the similarities and differences
00:03:20.570 --> 00:03:22.950
between plant and animal cells.
00:03:22.950 --> 00:03:25.080
As you go forward in your biology journey,
00:03:25.080 --> 00:03:27.910
you'll probably learn about a lot more.
00:03:27.910 --> 00:03:29.540
But the differences that we've covered
00:03:29.540 --> 00:03:32.560
are a big part of what
makes plant and animal cells
00:03:32.560 --> 00:03:35.320
so distinct and unique from each other.
00:03:35.320 --> 00:03:38.430
These differences are why
we don't see green lions
00:03:38.430 --> 00:03:41.270
that photosynthesize using chloroplasts
00:03:41.270 --> 00:03:45.980
or floppy raw veggies with cell
membranes but no cell walls.
00:03:45.980 --> 00:03:48.330
- Now I hope that you
have a clear understanding
00:03:48.330 --> 00:03:51.670
of the different cell parts in
both animal and plant cells,
00:03:51.670 --> 00:03:53.890
and that spotting the
differences between the two
00:03:53.890 --> 00:03:55.793
will be easy breezy.
|
Khan Academy Ed Talks with Ted Coe, PhD - Tuesday, March 15 | https://www.youtube.com/watch?v=f9j9pK8BkzU | vtt | https://www.youtube.com/api/timedtext?v=f9j9pK8BkzU&ei=wFWUZZj5CKmgp-oPoeaL8AM&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245296&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=7A66E0E9D349A650BE232334B9B3BEF46AC742EA.5B2B7350E4A463834CE1DED77E5E044912CB6170&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.330 --> 00:00:04.010
- Hello and welcome to Ed
Talks with Khan Academy.
00:00:04.010 --> 00:00:04.990
I'm Kristen DiCerbo,
00:00:04.990 --> 00:00:06.880
the Chief Learning
Officer at Khan Academy.
00:00:06.880 --> 00:00:11.140
And today, I am looking forward
to talking to Dr. Ted Coe,
00:00:11.140 --> 00:00:15.270
who is with NWEA, one of
our key partners here.
00:00:15.270 --> 00:00:18.340
He is the Director of
Content, Advocacy and Design.
00:00:18.340 --> 00:00:20.270
We're looking forward
to talking about math
00:00:20.270 --> 00:00:22.330
and math learning today.
00:00:22.330 --> 00:00:25.250
Before we get started, I wanna
remind you that Khan Academy
00:00:25.250 --> 00:00:29.180
is a nonprofit organization
and relies on donations
00:00:29.180 --> 00:00:31.920
from folks like you to help us continue
00:00:31.920 --> 00:00:32.930
to be able to do our work.
00:00:32.930 --> 00:00:36.230
So if you go to khanacademy.org/donate,
00:00:36.230 --> 00:00:39.500
you'll find a place where you
can help keep us supported
00:00:39.500 --> 00:00:43.250
and work in continuing our
work, so thank you for that.
00:00:43.250 --> 00:00:47.710
I also want to acknowledge
our corporate supporters
00:00:47.710 --> 00:00:49.980
who have come and helped us work
00:00:49.980 --> 00:00:53.580
through the COVID-19
crisis, including AT&T,
00:00:53.580 --> 00:00:56.290
General Motors, and Fastly.
00:00:56.290 --> 00:01:01.290
If you would like to
listen to this conversation
00:01:02.310 --> 00:01:04.860
or any of our previous conversations,
00:01:04.860 --> 00:01:07.230
you can, wherever you get your podcasts,
00:01:07.230 --> 00:01:09.950
find Homeroom with Sal, The Podcast
00:01:09.950 --> 00:01:13.170
and you'll be able to
listen wherever you prefer,
00:01:13.170 --> 00:01:17.580
at the gym, on your
walks, doing the dishes.
00:01:17.580 --> 00:01:18.683
We hope you enjoy it.
00:01:19.780 --> 00:01:24.780
So without further ado, let
me introduce Dr. Ted Coe.
00:01:25.080 --> 00:01:28.930
So he has over 25 years of
experience as a teacher,
00:01:28.930 --> 00:01:31.690
professor, department
chair, administrator,
00:01:31.690 --> 00:01:34.570
and a nonprofit director,
basically weaving together
00:01:34.570 --> 00:01:37.510
perspectives about mathematics education.
00:01:37.510 --> 00:01:39.400
He has experience as a full-time
00:01:39.400 --> 00:01:40.980
high school mathematics teacher,
00:01:40.980 --> 00:01:43.120
community college faculty member,
00:01:43.120 --> 00:01:45.550
a mathematics chair at
two community colleges,
00:01:45.550 --> 00:01:48.330
and an assistant dean
at the university level.
00:01:48.330 --> 00:01:52.410
And I will say, as
someone who is a graduate
00:01:52.410 --> 00:01:53.660
of Arizona State University,
00:01:53.660 --> 00:01:57.093
he is a fellow Sun Devil as well, welcome.
00:01:58.250 --> 00:02:00.773
- Thank you, thank you, glad to be here.
00:02:01.810 --> 00:02:03.150
- We are glad to have you.
00:02:03.150 --> 00:02:07.490
So first of all, tell us what
your role is specifically.
00:02:07.490 --> 00:02:09.053
What do you do at NWEA?
00:02:10.155 --> 00:02:12.955
- This is an interesting question, right?
00:02:12.955 --> 00:02:16.910
The answer is, the title
is Director of Content,
00:02:16.910 --> 00:02:19.550
Advocacy and Design for mathematics.
00:02:19.550 --> 00:02:21.660
And the interesting side to it is,
00:02:21.660 --> 00:02:23.740
well, I get to advocate for content.
00:02:23.740 --> 00:02:26.260
And so for many ways for me
00:02:26.260 --> 00:02:27.760
it's like this dream world to be in,
00:02:27.760 --> 00:02:30.710
where I get to kind of
imagine the kinds of things
00:02:30.710 --> 00:02:32.570
that we wanna work on,
how do we wanna grow,
00:02:32.570 --> 00:02:36.380
how do we want to move
beyond a focus on assessment
00:02:36.380 --> 00:02:40.140
to teaching and learning and
getting into the classroom
00:02:40.140 --> 00:02:43.410
and getting it, so it's
envisioning these kinds of things.
00:02:43.410 --> 00:02:46.050
It's being able to work with
different state and districts
00:02:46.050 --> 00:02:47.670
and get in there and roll up our sleeves
00:02:47.670 --> 00:02:49.890
and get our hands dirty trying to solve
00:02:49.890 --> 00:02:52.300
some pretty messy problems.
00:02:52.300 --> 00:02:55.090
So that's a lot of what I get to do.
00:02:55.090 --> 00:02:57.633
And so to me, it's great fun.
00:02:58.870 --> 00:03:01.550
- That's fantastic, how did
you come to be in this role?
00:03:01.550 --> 00:03:04.773
What was your path that
you took to end up here?
00:03:05.691 --> 00:03:10.543
- It was so bizarre, it's
a crazy path, career path,
00:03:12.350 --> 00:03:14.430
started out as a high school teacher,
00:03:14.430 --> 00:03:17.310
things were going well, I
loved high school teaching,
00:03:17.310 --> 00:03:19.380
highlight of the career, right?
00:03:19.380 --> 00:03:23.040
Then I ended up getting pulled over
00:03:23.040 --> 00:03:24.840
to one of the community colleges
00:03:24.840 --> 00:03:26.660
and I actually walked
right in my first job
00:03:26.660 --> 00:03:29.600
in the community college
system was as a chair
00:03:29.600 --> 00:03:30.900
at Rio Salado College
00:03:30.900 --> 00:03:32.530
in the Maricopa Community
College District.
00:03:32.530 --> 00:03:36.100
So it was like this big sort of leap.
00:03:36.100 --> 00:03:38.890
I ended up switching over
to another community college
00:03:38.890 --> 00:03:42.270
in the district, Scotts
Dale and while I was there,
00:03:42.270 --> 00:03:46.810
I ended up being involved
deeply in the mathematics
00:03:46.810 --> 00:03:48.790
around the whole community college system
00:03:48.790 --> 00:03:51.690
and kind of involved in the
articulation conversations
00:03:51.690 --> 00:03:53.000
around the state and everything.
00:03:53.000 --> 00:03:57.580
And somewhere along that time
the Park Consortium came along
00:03:57.580 --> 00:03:58.413
and you might remember this,
00:03:58.413 --> 00:03:59.960
this was in the early
years of the common core
00:03:59.960 --> 00:04:01.860
and there were the two major consortium,
00:04:01.860 --> 00:04:03.660
Park and Smarter Balanced.
00:04:03.660 --> 00:04:07.790
And I was brought on to the
Park side of the conversation.
00:04:07.790 --> 00:04:10.910
Arizona was one of the
governing states at the time.
00:04:10.910 --> 00:04:11.743
And I was brought in
00:04:11.743 --> 00:04:14.090
as one of the higher ed content experts.
00:04:14.090 --> 00:04:16.080
And so I was dropped into
this space all of a sudden,
00:04:16.080 --> 00:04:18.940
where I had been a college professor
00:04:18.940 --> 00:04:21.780
and high school teacher and
now I was in this space,
00:04:21.780 --> 00:04:23.020
where it's like, we want your input
00:04:23.020 --> 00:04:25.300
on this multi-state assessment
00:04:25.300 --> 00:04:26.700
that's on these new standards.
00:04:26.700 --> 00:04:28.000
And so I'm like, "Well,
let's read the standards,
00:04:28.000 --> 00:04:29.700
let's see what this is about."
00:04:29.700 --> 00:04:32.920
And I got really involved
in it and so much, in fact
00:04:32.920 --> 00:04:36.250
that eventually Park
split off of the group
00:04:36.250 --> 00:04:38.060
that was running it,
which was called Achieve.
00:04:38.060 --> 00:04:41.150
And Achieve was the ones for
the American Diploma Product,
00:04:41.150 --> 00:04:42.730
helped lead the common core and all that,
00:04:42.730 --> 00:04:44.800
and the next generation science standards.
00:04:44.800 --> 00:04:47.380
And so they only hired me
to be their math director.
00:04:47.380 --> 00:04:52.290
And so for the years prior
to coming into this space
00:04:52.290 --> 00:04:54.570
at NWEA where I've been for two years,
00:04:54.570 --> 00:04:56.990
I was the director of mathematics
there and got to work all
00:04:56.990 --> 00:04:59.740
around the country with
great folks everywhere.
00:04:59.740 --> 00:05:03.797
And really get to see how
the policies worked out
00:05:03.797 --> 00:05:05.880
and the difficulties that
people were encountering
00:05:05.880 --> 00:05:07.607
and trying to talk through
some of those things
00:05:07.607 --> 00:05:09.497
and getting the chance to
speak all over the country.
00:05:09.497 --> 00:05:11.507
It was great fun, it's been great fun
00:05:11.507 --> 00:05:15.760
and it's been it one
surprise after the other.
00:05:15.760 --> 00:05:17.083
And here I am today.
00:05:18.160 --> 00:05:19.950
- Fantastic, that sounds great.
00:05:19.950 --> 00:05:23.373
So let's talk a little bit
about teaching and leaning math.
00:05:24.320 --> 00:05:28.260
Historically, there's been
all this discussion about,
00:05:28.260 --> 00:05:30.850
should we teach procedural skills?
00:05:30.850 --> 00:05:33.440
Should we teach conceptual understanding?
00:05:33.440 --> 00:05:37.260
And these wars about which
one is more important
00:05:37.260 --> 00:05:38.140
and where these is,
00:05:38.140 --> 00:05:40.340
is that the right
conversation to be having?
00:05:41.732 --> 00:05:44.270
- It's a tale as old as time,
00:05:44.270 --> 00:05:46.310
at least as old as my
career has been, right?
00:05:46.310 --> 00:05:49.290
But there's always this tension in there.
00:05:49.290 --> 00:05:53.118
And so I've had to sit
back and think to myself
00:05:53.118 --> 00:05:56.920
how would I describe teaching
and learning mathematics
00:05:56.920 --> 00:05:58.950
after my 20 years of teaching?
00:05:58.950 --> 00:06:02.420
And I was like, "Well,
how do I sum this up?"
00:06:02.420 --> 00:06:04.230
And it was somehow
developed along the way,
00:06:04.230 --> 00:06:07.630
but it was this idea that
look, part of what we do
00:06:07.630 --> 00:06:11.030
in mathematics is we
teach these ways of doing
00:06:12.290 --> 00:06:13.780
and we want you to be able to do those
00:06:13.780 --> 00:06:16.190
but we also wanna make
sure that you're picking up
00:06:16.190 --> 00:06:18.710
ways of thinking, and I'll
give you an example of that
00:06:18.710 --> 00:06:22.440
in just a moment, that go
alongside habits of thinking.
00:06:22.440 --> 00:06:25.260
So you have these ways of
thinking sort of at a core
00:06:25.260 --> 00:06:28.620
that are bolstered by
these habits of thinking
00:06:28.620 --> 00:06:32.710
that are then in turn
really sort of brought,
00:06:32.710 --> 00:06:34.220
they come to the table in certain ways,
00:06:34.220 --> 00:06:36.500
through the ways of doing
that allow you to go on
00:06:36.500 --> 00:06:39.580
and do something bigger
with the mathematics.
00:06:39.580 --> 00:06:41.910
An example I use quite frequently
00:06:41.910 --> 00:06:43.970
is with this idea of ways of thinking.
00:06:43.970 --> 00:06:46.390
And I can ask a room full
of adults this question
00:06:46.390 --> 00:06:47.837
and basically I say something like,
00:06:47.837 --> 00:06:52.210
"Hey, how many years was
it from December 7th, 1941
00:06:53.730 --> 00:06:54.887
to December 7th, 2014?"
00:06:56.220 --> 00:06:57.790
That's how long I've
been using this question.
00:06:57.790 --> 00:07:02.790
Okay, so December 7th
2014 and by and large
00:07:04.950 --> 00:07:08.010
you ask this to a room
full of even adults, right?
00:07:08.010 --> 00:07:10.830
And people will sit there
and they start chewing on
00:07:10.830 --> 00:07:12.782
an answer and they start,
"Oh, what can I do?
00:07:12.782 --> 00:07:13.615
What can I do?"
00:07:13.615 --> 00:07:15.060
And they go through some
mechanizations in their head
00:07:15.060 --> 00:07:15.977
and they might think,
00:07:15.977 --> 00:07:19.050
"Well, that's actually kind
of a subtraction problem
00:07:19.050 --> 00:07:22.370
but I don't really need to
use subtraction to get it,"
00:07:22.370 --> 00:07:23.890
because in this case, I'm just trying
00:07:23.890 --> 00:07:26.660
to find this additive comparison
and this gap, if you will,
00:07:26.660 --> 00:07:28.160
between the two numbers
00:07:28.160 --> 00:07:29.320
and there are different ways to do it.
00:07:29.320 --> 00:07:32.220
Maybe I wanna go from
1941 to 2000, cut it off,
00:07:32.220 --> 00:07:33.850
and then go from 2000 to 2014,
00:07:33.850 --> 00:07:35.910
or maybe I wanna take the whole thing.
00:07:35.910 --> 00:07:37.280
So starting in 1941,
00:07:37.280 --> 00:07:42.280
I wanna slide the whole thing
back a year and start at 1940.
00:07:42.460 --> 00:07:44.760
Either way, all of these things are fair
00:07:44.760 --> 00:07:48.730
but the majority of the
folks I asked that question,
00:07:48.730 --> 00:07:51.050
they don't answer it
with the way of doing,
00:07:51.050 --> 00:07:53.790
they don't do the 15 steps
of setting up the algorithm,
00:07:53.790 --> 00:07:55.940
borrowing, not giving back all that thing,
00:07:55.940 --> 00:07:58.699
putting the one, they don't do that,
00:07:58.699 --> 00:08:02.740
they bring ways of
thinking to bear, right?
00:08:02.740 --> 00:08:03.580
- Yeah.
00:08:03.580 --> 00:08:07.300
- And I think maybe part of
why we get into this mess
00:08:07.300 --> 00:08:11.020
is in the standards, we have
the learning progressions
00:08:11.020 --> 00:08:15.030
and the learning progressions
and with the ways of doing.
00:08:15.030 --> 00:08:17.660
And so it looks like the
way of doing is the goal,
00:08:17.660 --> 00:08:20.230
but the way of doing
is just one more thing,
00:08:20.230 --> 00:08:22.830
it's just one more piece, right?
00:08:22.830 --> 00:08:25.620
Yeah, so I really like to emphasize
00:08:25.620 --> 00:08:29.340
this idea of ways of
thinking with regards to
00:08:29.340 --> 00:08:31.210
ways of thinking, ways of
doing, habits of thinking,
00:08:31.210 --> 00:08:33.640
all of those things working together.
00:08:33.640 --> 00:08:36.130
'Cause if you have just
one, the ways of doing,
00:08:36.130 --> 00:08:38.870
all you've got is a box of puzzle pieces
00:08:38.870 --> 00:08:40.723
when you're done with it, yeah.
00:08:41.606 --> 00:08:44.650
- Right, so I'm gonna keep
going with the year example here
00:08:44.650 --> 00:08:48.240
to push on this, so my
sister got married in 1997
00:08:48.240 --> 00:08:52.050
and I have to say, somehow
never made this connection,
00:08:52.050 --> 00:08:53.667
but she said to me one day,
00:08:53.667 --> 00:08:55.190
"If you wanna know how
long we've been married,
00:08:55.190 --> 00:08:57.360
you just take what current
year it is in add three,
00:08:57.360 --> 00:08:58.713
because 1997 to 2003."
00:09:00.660 --> 00:09:03.757
Then I was like, "Oh yeah,
why did I not think of that?"
00:09:03.757 --> 00:09:04.670
(Kristen laughing)
00:09:04.670 --> 00:09:09.140
So that's a way of doing
it, so then that's one way,
00:09:09.140 --> 00:09:11.780
or is that how does that relate
then to ways of thinking?
00:09:11.780 --> 00:09:15.680
And so are there many
different ways you can do it
00:09:15.680 --> 00:09:17.320
and the ways of thinking around it?
00:09:17.320 --> 00:09:20.350
- Yes, the idea is that
when I ask that question,
00:09:20.350 --> 00:09:23.030
there are so many different
ways you could approach it.
00:09:23.030 --> 00:09:25.320
You could approach it with a way of doing
00:09:25.320 --> 00:09:26.530
and no harm, no foul.
00:09:26.530 --> 00:09:28.240
You could approach it
with ways of thinking,
00:09:28.240 --> 00:09:30.170
but if all you have is the way of doing
00:09:30.170 --> 00:09:32.160
and you don't have those ways of thinking,
00:09:32.160 --> 00:09:34.830
then when you get to
somewhere in real life,
00:09:34.830 --> 00:09:36.500
it doesn't illuminate.
00:09:36.500 --> 00:09:40.586
And a place where this
happens is you can ask
00:09:40.586 --> 00:09:43.280
like where in real life,
ask this to an adult,
00:09:43.280 --> 00:09:45.560
where in real life have
you ever actually used
00:09:45.560 --> 00:09:47.013
division of fractions?
00:09:47.880 --> 00:09:49.820
And I'll be surprised if you actually get
00:09:49.820 --> 00:09:54.740
any valid answer back from
anybody and why is that?
00:09:54.740 --> 00:09:57.130
Because if we reflect back to it,
00:09:57.130 --> 00:10:00.100
when we were taught the
division of fractions,
00:10:00.100 --> 00:10:02.630
those of us who were of
a certain age, right?
00:10:02.630 --> 00:10:04.780
We were caught a way of doing
00:10:04.780 --> 00:10:08.790
and it was totally disconnected
from ways of thinking
00:10:08.790 --> 00:10:12.280
grounded in what does it
mean to divide so that-
00:10:12.280 --> 00:10:16.180
- Yes, you were just
taught the procedure, yeah.
00:10:16.180 --> 00:10:18.450
- Yeah and so you've got the procedure
00:10:18.450 --> 00:10:20.170
but you have no place to hang it,
00:10:20.170 --> 00:10:22.380
when it comes and shows up in real life.
00:10:22.380 --> 00:10:26.650
- Right, that totally makes
sense, so if I'm a teacher
00:10:26.650 --> 00:10:29.710
how do I start thinking about encouraging
00:10:29.710 --> 00:10:31.103
these ways of thinking?
00:10:32.500 --> 00:10:34.513
- See, that's the tricky part, right?
00:10:35.526 --> 00:10:36.359
- Right?
00:10:36.359 --> 00:10:41.120
- Yeah, and so one really
cool thing that happened
00:10:42.180 --> 00:10:43.980
in the last couple years, Peter Liljedahl
00:10:43.980 --> 00:10:47.050
came out with a book called
"Building Thinking Classrooms."
00:10:47.050 --> 00:10:49.420
And I'm like, yes, yes, we're seeing
00:10:49.420 --> 00:10:52.460
this emphasis shifting
to thinking, fantastic.
00:10:52.460 --> 00:10:56.623
Because at the same time
my colleagues and I at NWEA
00:10:56.623 --> 00:11:00.030
have been trying to work on this idea
00:11:00.030 --> 00:11:02.850
of how can we get ways of thinking moving
00:11:02.850 --> 00:11:04.450
and talked about in classrooms
00:11:04.450 --> 00:11:06.810
in ways that are non-threatening, right?
00:11:06.810 --> 00:11:09.640
That feel safe to both
teachers and students
00:11:09.640 --> 00:11:13.790
because there's awkwardness
when we ask ourselves
00:11:13.790 --> 00:11:16.890
thinking questions, all of
us have to stop and think,
00:11:16.890 --> 00:11:20.300
and with thinking comes
vulnerability, right?
00:11:20.300 --> 00:11:24.170
So we actually built out some things
00:11:24.170 --> 00:11:26.860
called these formative
conversation starters.
00:11:26.860 --> 00:11:29.300
And the role of the formative
conversation starters
00:11:29.300 --> 00:11:33.250
is to basically help shape
how you might enter into
00:11:33.250 --> 00:11:34.930
some of these kinds of conversations
00:11:34.930 --> 00:11:37.910
that are designed to
focus on ways of thinking
00:11:39.420 --> 00:11:42.830
and then to do it in such
a way that you also know
00:11:42.830 --> 00:11:46.760
what it is you're trying to
listen for at the same time.
00:11:46.760 --> 00:11:48.470
So we've got these bins,
00:11:48.470 --> 00:11:50.920
these big ideas to nurture sense making
00:11:50.920 --> 00:11:54.300
and then we've got clusters of questions
00:11:54.300 --> 00:11:57.623
that unfold as you ask them and might lead
00:11:57.623 --> 00:12:01.010
to moments of cognitive
dissonance or might lead to ahas
00:12:01.010 --> 00:12:04.217
or might lead to places
where you step back and go,
00:12:04.217 --> 00:12:07.077
"I really do need to think
more deeply about that."
00:12:08.115 --> 00:12:10.250
So there are different options to do it.
00:12:10.250 --> 00:12:14.302
You can put in classroom
routines, you can build tools,
00:12:14.302 --> 00:12:16.213
like we're trying to build out.
00:12:17.830 --> 00:12:21.507
But the idea is what can we do to do that?
00:12:21.507 --> 00:12:24.590
All kinds of things, like
Peter's got in his book,
00:12:24.590 --> 00:12:26.420
all kinds of options,
00:12:26.420 --> 00:12:29.670
as well as what I'm offering here today.
00:12:29.670 --> 00:12:32.100
- Yeah, so I like this idea
of conversation starters.
00:12:32.100 --> 00:12:36.170
I think we're putting a
link to them in the chat
00:12:36.170 --> 00:12:38.940
for folks that are following along.
00:12:38.940 --> 00:12:41.700
Can you give us some examples,
what are some examples
00:12:41.700 --> 00:12:43.840
of what these are and how do they work?
00:12:43.840 --> 00:12:48.840
- Yeah, so, and sometimes
the idea like with fractions,
00:12:51.410 --> 00:12:54.346
I might come out and we might
start with a question like,
00:12:54.346 --> 00:12:56.280
well, what's a fraction?
00:12:56.280 --> 00:12:58.120
And then, well, the
next question might be,
00:12:58.120 --> 00:13:01.470
well, is a fraction one
number or two numbers?
00:13:01.470 --> 00:13:03.700
And just sit back and talk about it.
00:13:03.700 --> 00:13:06.350
Talk about what you
think on that, all right?
00:13:06.350 --> 00:13:08.420
And then, well, what do you think of
00:13:08.420 --> 00:13:10.193
when you think of three eighths?
00:13:11.140 --> 00:13:14.170
Okay, what do you think of
when you see eight thirds?
00:13:14.170 --> 00:13:16.840
'Cause if you're of three
eighths as three out of eight,
00:13:16.840 --> 00:13:18.360
then eight thirds becomes something
00:13:18.360 --> 00:13:21.230
that's maybe a little
tougher to think about.
00:13:21.230 --> 00:13:23.560
Another example would be
a question that starts off
00:13:23.560 --> 00:13:27.840
with like, well, what
does division do for us?
00:13:27.840 --> 00:13:29.210
And so you wanna sit
back and you think about,
00:13:29.210 --> 00:13:31.110
well, what does division do for us?
00:13:31.110 --> 00:13:32.640
And then the next question would be
00:13:32.640 --> 00:13:36.280
not to do a division problem,
but to ask a question like,
00:13:39.628 --> 00:13:42.620
without computing how can you
think about a problem like
00:13:42.620 --> 00:13:44.090
10 divided by one half
00:13:45.250 --> 00:13:48.660
and to be able to go on to the next one.
00:13:48.660 --> 00:13:51.090
Well, then how would you
think about negative 10
00:13:51.090 --> 00:13:53.060
divided by one half, right?
00:13:53.060 --> 00:13:56.720
And if your ways of thinking
are consistent and robust,
00:13:56.720 --> 00:13:59.130
then your answers were
sort of gel together
00:13:59.130 --> 00:14:02.610
but if you have fractures
and if they're disjoint,
00:14:02.610 --> 00:14:04.220
then you kind of have to go back
00:14:04.220 --> 00:14:06.150
and kind of try to figure
out, well, how do I get the,
00:14:06.150 --> 00:14:09.340
I know that my thinking should
gel together with my answers
00:14:09.340 --> 00:14:12.110
to all of these things,
what do I need to do?
00:14:12.110 --> 00:14:13.920
How do I need to accommodate
the way I'm thinking
00:14:13.920 --> 00:14:16.390
in order to make these things work?
00:14:16.390 --> 00:14:18.050
From the teacher's perspective,
00:14:18.050 --> 00:14:21.470
we help provide what you might
be listening for in these-
00:14:21.470 --> 00:14:23.087
- I was just gonna ask that.
00:14:23.087 --> 00:14:24.686
(Kristen laughing)
00:14:24.686 --> 00:14:26.620
Yeah, what are the things
that you're looking for
00:14:26.620 --> 00:14:28.335
from the teacher's perspective?
00:14:28.335 --> 00:14:31.557
- Yeah, so like we know
that we want fraction
00:14:31.557 --> 00:14:34.330
and we want students to be
able to think of a fraction
00:14:34.330 --> 00:14:39.330
as a single number, as a point
on the number line, right?
00:14:39.870 --> 00:14:43.940
But if I ask my students about fractions
00:14:43.940 --> 00:14:44.773
and they're saying,
00:14:44.773 --> 00:14:48.130
"Well, we're only thinking
of it as two numbers."
00:14:48.130 --> 00:14:50.870
Then I'm talking about
something as the teacher
00:14:50.870 --> 00:14:53.860
that's completely different
from what they're hearing.
00:14:53.860 --> 00:14:56.420
And so it's this idea of
getting these meanings
00:14:56.420 --> 00:14:58.960
out in the open so that we all know
00:14:58.960 --> 00:15:00.920
that we're talking about the same thing,
00:15:00.920 --> 00:15:03.660
so when I say fraction, you're
thinking the same thing.
00:15:03.660 --> 00:15:05.540
Or when I talk about division,
00:15:05.540 --> 00:15:07.570
you've got a notion of thinking of it
00:15:07.570 --> 00:15:09.750
as a multiplicative comparison.
00:15:09.750 --> 00:15:11.930
Or you've got way of
thinking about it in terms of
00:15:11.930 --> 00:15:14.210
how many copies of run
thing are in another,
00:15:14.210 --> 00:15:17.690
or this time's as large
as this thing, right?
00:15:17.690 --> 00:15:19.030
Which when you have those ways of thinking
00:15:19.030 --> 00:15:19.863
that a question like,
00:15:19.863 --> 00:15:21.530
how can you think of
10 divided by one half,
00:15:21.530 --> 00:15:24.610
doesn't become something
that's out of bounds at all.
00:15:24.610 --> 00:15:26.320
It becomes something that
you can already hang onto
00:15:26.320 --> 00:15:28.888
one of those previous
existing meanings of division,
00:15:28.888 --> 00:15:32.370
if they're there, if you've
got those ways of thinking.
00:15:32.370 --> 00:15:35.020
- Right, right, yeah, that makes sense.
00:15:35.020 --> 00:15:39.855
So do these starters work
across ages and grade levels?
00:15:39.855 --> 00:15:42.190
Are there things that we need to be,
00:15:42.190 --> 00:15:43.957
what kinds of things can younger kids do
00:15:43.957 --> 00:15:47.460
and what kinds of things
can older kids start to get?
00:15:47.460 --> 00:15:50.850
- So the interesting thing
about them is the way,
00:15:50.850 --> 00:15:52.810
if you go download, maybe
some people have already gone
00:15:52.810 --> 00:15:54.830
to download the documents
just while we're sitting here.
00:15:54.830 --> 00:15:59.230
But you'll see the entry point
into this is through an item,
00:15:59.230 --> 00:16:02.040
it's through a standard, but the idea is
00:16:02.040 --> 00:16:06.500
we've spent so many years
unpacking standards,
00:16:06.500 --> 00:16:08.990
digging in and saying, let's
look at this one standard.
00:16:08.990 --> 00:16:09.970
What we wanna do is say,
00:16:09.970 --> 00:16:12.630
we're only using this as the entry point,
00:16:12.630 --> 00:16:14.370
because what we wanna
do is we wanna find out,
00:16:14.370 --> 00:16:17.270
what is all of the other
mathematics that has to come in
00:16:17.270 --> 00:16:20.480
alongside it to help get through this.
00:16:20.480 --> 00:16:23.080
We tend to look at an item
go, this is the standard.
00:16:23.080 --> 00:16:24.360
And then we say, well,
if they get it wrong,
00:16:24.360 --> 00:16:25.193
then we wanna go back
00:16:25.193 --> 00:16:27.020
and go to that nearest
connecting standard.
00:16:27.020 --> 00:16:29.130
What we're saying here is
actually maybe you wanna go
00:16:29.130 --> 00:16:31.903
ask them about what's a fraction, right?
00:16:31.903 --> 00:16:32.951
- Right.
00:16:32.951 --> 00:16:35.090
- So let's go talk about
what a fraction is.
00:16:35.090 --> 00:16:37.270
It might not be the
nearest neighbor standard
00:16:37.270 --> 00:16:39.500
that's the issue, it could
be some ways of thinking
00:16:39.500 --> 00:16:41.890
that endure and that goes
back to your question
00:16:41.890 --> 00:16:43.570
about who are these for?
00:16:43.570 --> 00:16:47.390
Well, you can take the ones
that we've got packaged
00:16:47.390 --> 00:16:48.770
in the third grade and ask them*8
00:16:48.770 --> 00:16:50.100
to seventh and eighth graders,
00:16:50.100 --> 00:16:53.450
because the ways of thinking
are enduring, right?
00:16:53.450 --> 00:16:56.100
And so the ideas are, yes,
they grow a little bit,
00:16:56.100 --> 00:16:58.230
but they endure and they
grew out of these things,
00:16:58.230 --> 00:17:02.460
actually grew out of, are
thinking about what could we help
00:17:02.460 --> 00:17:07.060
to provide teachers with as
we move into this phase now,
00:17:07.060 --> 00:17:08.070
where students are coming with
00:17:08.070 --> 00:17:11.130
such uneven opportunities to learn.
00:17:11.130 --> 00:17:12.790
And philosophically I'd say,
00:17:12.790 --> 00:17:15.020
well, I can't just be
focus on ways of doing.
00:17:15.020 --> 00:17:17.107
I have to be focusing some
way on the ways of thinking
00:17:17.107 --> 00:17:20.320
and these habits of thinking
that come alongside it.
00:17:20.320 --> 00:17:21.940
And so what could we do?
00:17:21.940 --> 00:17:23.540
That's where we ended up with this.
00:17:23.540 --> 00:17:26.970
So if you are a third grade teacher,
00:17:26.970 --> 00:17:28.140
you could probably pull stuff
00:17:28.140 --> 00:17:29.610
from the fourth and fifth grade.
00:17:29.610 --> 00:17:30.870
If you are a high school teacher,
00:17:30.870 --> 00:17:32.940
you can pull things
from any grades, right?
00:17:32.940 --> 00:17:34.890
And they'll still be fair game
00:17:34.890 --> 00:17:36.480
because there're things to talk about,
00:17:36.480 --> 00:17:39.450
ideas that endure that go on and on.
00:17:39.450 --> 00:17:40.790
So if you're in high school,
00:17:40.790 --> 00:17:42.130
you might dig into the functions,
00:17:42.130 --> 00:17:43.330
you might dig into comparison,
00:17:43.330 --> 00:17:45.030
you might dig into operations.
00:17:45.030 --> 00:17:48.300
I hope you dig into
proportional relationships.
00:17:48.300 --> 00:17:52.629
- Yes, so this whole conversation
is making me think about
00:17:52.629 --> 00:17:55.580
something that we talk a lot
about at Khan Academy which is,
00:17:55.580 --> 00:17:57.970
what Sal used to call Swiss cheese gaps
00:17:57.970 --> 00:18:00.520
but now everyone calls
unfinished learning.
00:18:00.520 --> 00:18:04.370
Which is the idea that lots of folks
00:18:04.370 --> 00:18:07.870
didn't get some of those
foundational concepts
00:18:07.870 --> 00:18:12.250
and when they were first
presented and so try to then build
00:18:12.250 --> 00:18:14.490
the next level without those concepts,
00:18:14.490 --> 00:18:18.093
which is kinda the shaky
foundation and it just keeps going.
00:18:19.010 --> 00:18:23.300
So it sounds like these
conversation starters
00:18:23.300 --> 00:18:27.390
are starting to think about
almost diagnosing in some ways,
00:18:27.390 --> 00:18:29.303
like do you have those-
00:18:30.140 --> 00:18:32.750
- Do you have the ways of thinking, right?
00:18:32.750 --> 00:18:37.140
The foundational ways
of thinking which are,
00:18:37.140 --> 00:18:39.340
when you look at your state standards,
00:18:39.340 --> 00:18:41.990
you're going to see them kind of in there,
00:18:41.990 --> 00:18:43.620
but you might not see them as explicit
00:18:43.620 --> 00:18:45.470
as we're trying to call them out here.
00:18:45.470 --> 00:18:46.990
Like these are some core ones
00:18:46.990 --> 00:18:48.420
that you wanna keep coming back to.
00:18:48.420 --> 00:18:52.810
You wanna keep revisiting
these and keep listening.
00:18:52.810 --> 00:18:55.870
And so the kinds of questions
that we're putting out here,
00:18:55.870 --> 00:18:58.720
use them however you wanna
use them, use them full class,
00:18:58.720 --> 00:19:00.990
use them one on one, use
them in small groups,
00:19:00.990 --> 00:19:02.340
use them for turning talks,
00:19:04.340 --> 00:19:06.973
the idea is to sit back and listen.
00:19:08.791 --> 00:19:11.503
What we would point out
is it's also not intended,
00:19:14.370 --> 00:19:17.680
there will be a teachable
moment, it's not during this time
00:19:17.680 --> 00:19:19.910
because we wanna set up the
culture in such a way that
00:19:19.910 --> 00:19:24.200
this is free, open up, tell
me what you're thinking
00:19:24.200 --> 00:19:26.530
and it's not to correct, it's to listen.
00:19:26.530 --> 00:19:27.790
And what's interesting about that, right?
00:19:27.790 --> 00:19:29.760
Is if you keep asking more questions,
00:19:29.760 --> 00:19:31.950
you might realize that your first thoughts
00:19:31.950 --> 00:19:35.160
about what people like
to call misconceptions
00:19:35.160 --> 00:19:36.630
could be completely wrong.
00:19:36.630 --> 00:19:40.088
That you've misconceived
their misconceptions.
00:19:40.088 --> 00:19:41.160
(both laughing)
00:19:41.160 --> 00:19:42.690
I don't like using the word misconceptions
00:19:42.690 --> 00:19:45.560
'cause the students have the conceptions
00:19:45.560 --> 00:19:46.860
and this is all about,
00:19:46.860 --> 00:19:49.740
what conceptions might they have, right?
00:19:49.740 --> 00:19:51.930
Not what don't they have, what
conceptions might they have?
00:19:51.930 --> 00:19:54.320
How are they thinking about these things?
00:19:54.320 --> 00:19:57.300
And let's build from that,
that connects back very closely
00:19:57.300 --> 00:20:01.330
to Sal's house building analogy, right?
00:20:01.330 --> 00:20:02.647
- Yeah, right.
00:20:02.647 --> 00:20:04.870
- These are these foundational,
00:20:04.870 --> 00:20:06.500
it's more like these foundational threads
00:20:06.500 --> 00:20:08.550
that wind their way all the way through,
00:20:08.550 --> 00:20:12.910
not just on the bottom floor
but you just keep continuing
00:20:12.910 --> 00:20:15.290
to strengthen them like
the trunk of a tree, right?
00:20:15.290 --> 00:20:17.940
It just keeps getting
stronger and stronger.
00:20:17.940 --> 00:20:20.810
- Yeah, absolutely, that
totally makes sense.
00:20:20.810 --> 00:20:25.280
How do you think about the
idea of mastery in this world?
00:20:25.280 --> 00:20:28.080
We talk a lot about mastery learning here
00:20:28.080 --> 00:20:31.370
and thinking it's easy when
you're talking about skills
00:20:31.370 --> 00:20:33.500
and having mastery of skills,
00:20:33.500 --> 00:20:37.370
but mastery of some of these
things is somewhat different.
00:20:37.370 --> 00:20:39.040
Is that even a valid concept?
00:20:39.040 --> 00:20:39.890
I don't know.
00:20:39.890 --> 00:20:43.256
- Yeah, it's so hard
to say what is mastery.
00:20:43.256 --> 00:20:46.510
I mean, we always wanna draw a line
00:20:46.510 --> 00:20:48.521
for proficiency somewhere, right?
00:20:48.521 --> 00:20:49.354
- Right.
00:20:49.354 --> 00:20:50.820
- What it means to have learned something
00:20:50.820 --> 00:20:53.690
but in this mindset on
the ways of thinking,
00:20:53.690 --> 00:20:55.690
it's like these are things
that continue to grow
00:20:55.690 --> 00:20:57.963
and morph and evolve.
00:20:58.808 --> 00:21:03.410
And as I think about, well,
how do we ever establish
00:21:03.410 --> 00:21:04.750
whether students have mastered this?
00:21:04.750 --> 00:21:07.570
I'm not sure that that's even
the right type of question.
00:21:07.570 --> 00:21:09.760
But rather to just likely,
it's just to keep on
00:21:09.760 --> 00:21:13.040
how is that scheme of
building up in their minds
00:21:13.040 --> 00:21:17.110
as they continue to go and
how can I leverage that
00:21:17.110 --> 00:21:19.290
to go on to that next place?
00:21:19.290 --> 00:21:21.810
- Right and you can think
about how you would expect
00:21:21.810 --> 00:21:25.210
some of these answers to
change as you learn new things,
00:21:25.210 --> 00:21:27.790
you're changing your
ideas about what these are
00:21:27.790 --> 00:21:29.750
as you kind of move up through new skills
00:21:29.750 --> 00:21:32.670
and things you're developing, interesting.
00:21:32.670 --> 00:21:35.820
So we obviously do a lot with technology
00:21:35.820 --> 00:21:37.630
but we also wanna think about
00:21:37.630 --> 00:21:41.010
how teachers and technology work together.
00:21:41.010 --> 00:21:44.904
And so I'm interested
in your thoughts about,
00:21:44.904 --> 00:21:47.680
the interplay between
the two is I think about
00:21:47.680 --> 00:21:48.890
what you're talking about,
00:21:48.890 --> 00:21:50.570
things technology's never gonna be good
00:21:50.570 --> 00:21:53.160
at doing what you're talking
about, that's like the thing
00:21:53.160 --> 00:21:55.130
that teachers need to be in classrooms.
00:21:55.130 --> 00:21:58.497
So I'm interested in your
thoughts about how teachers
00:21:58.497 --> 00:22:00.747
and technology can work
together to build on.
00:22:02.880 --> 00:22:06.730
- Yeah, so I'm happy to
hear you see it that way
00:22:06.730 --> 00:22:08.516
'cause that's how I see it.
00:22:08.516 --> 00:22:12.993
It's that idea that
computers, they're really good
00:22:16.070 --> 00:22:18.347
at helping with that way
of doing things, right?
00:22:18.347 --> 00:22:19.480
- Right.
00:22:19.480 --> 00:22:22.110
- But to sort of put these complex
00:22:22.110 --> 00:22:23.460
ways of thinking together,
00:22:23.460 --> 00:22:26.436
I mean, that takes some time
and working and developing
00:22:26.436 --> 00:22:31.436
and to me I see a very human side to that
00:22:31.818 --> 00:22:36.818
that would be very hard to
capture with a computer system.
00:22:37.090 --> 00:22:41.695
So each can play a very
important role, right?
00:22:41.695 --> 00:22:46.695
So the computers provide
an here to foreseen access
00:22:51.840 --> 00:22:55.667
to content in ways that we've
never seen before, right?
00:22:55.667 --> 00:22:58.200
And so building that up,
but that next task is,
00:22:58.200 --> 00:23:02.130
well, how do we take that
access that we've now shared,
00:23:02.130 --> 00:23:04.630
but how do we build in
these kinds of things?
00:23:04.630 --> 00:23:07.960
What can we have the computers
help to support us with
00:23:07.960 --> 00:23:10.850
when it comes to engaging in
these kinds of conversations
00:23:10.850 --> 00:23:13.280
that will be able to help
sort of listen to students
00:23:13.280 --> 00:23:16.620
and figure out exactly sort
of what might the next move be
00:23:16.620 --> 00:23:19.570
based on ways of thinking,
not necessarily just the ways
00:23:19.570 --> 00:23:21.850
of doing as you might see
pointed out in standards
00:23:21.850 --> 00:23:24.043
and standards mappings, that kinda thing.
00:23:25.060 --> 00:23:26.900
- Yeah, absolutely.
00:23:26.900 --> 00:23:31.060
So another piece that we try to encourage
00:23:31.060 --> 00:23:33.700
is helping students become
owners of their own learning
00:23:33.700 --> 00:23:37.130
and thinking about developing
those metacognitive skills.
00:23:37.130 --> 00:23:39.170
Being able to understand what they know
00:23:39.170 --> 00:23:41.240
and evaluate and what they understand
00:23:41.240 --> 00:23:43.823
and need to learn and how those fit in.
00:23:44.660 --> 00:23:46.210
I'm interested in how you think about that
00:23:46.210 --> 00:23:48.930
and some of this framework too.
00:23:48.930 --> 00:23:52.220
- Yeah, well that might land
in that habits space, right?
00:23:52.220 --> 00:23:54.870
Being able to reflect on and
being honest with myself,
00:23:54.870 --> 00:23:56.630
am I making sense?
00:23:56.630 --> 00:24:00.243
In my own mind can I
justify what I'm saying?
00:24:01.370 --> 00:24:04.573
Or am I just spouting things off?
00:24:05.910 --> 00:24:08.900
So maybe part of that is that you can
00:24:08.900 --> 00:24:13.560
with this type of approach you
really do get the opportunity
00:24:13.560 --> 00:24:17.710
for the student to reflect
by not correcting right away,
00:24:17.710 --> 00:24:20.080
by continuing to ask questions.
00:24:20.080 --> 00:24:22.530
You're providing the student
opportunities to reflect
00:24:22.530 --> 00:24:27.150
and then maybe when it's
done and then you sit down
00:24:27.150 --> 00:24:29.290
with the student and
then you help them have
00:24:29.290 --> 00:24:31.320
some metacognitive reflection on it.
00:24:31.320 --> 00:24:33.620
What would you like to work on it?
00:24:33.620 --> 00:24:36.040
What questions did you
answer that you felt like
00:24:36.040 --> 00:24:38.800
you wanted to take back
or think through again,
00:24:38.800 --> 00:24:41.250
or think more about or
learn more about, right?
00:24:41.250 --> 00:24:45.250
To help them spot where they need ways
00:24:45.250 --> 00:24:48.120
they wanted to strengthen
their ways of thinking.
00:24:48.120 --> 00:24:49.120
- Yeah, that makes sense.
00:24:49.120 --> 00:24:53.450
I think that idea of
helping of thinking about
00:24:54.930 --> 00:24:57.000
your confidence in your answers
00:24:57.000 --> 00:24:58.730
is something that we talk about too,
00:24:58.730 --> 00:25:01.710
like after students give
answers having them think about,
00:25:01.710 --> 00:25:03.540
so how sure of you were with that answer
00:25:03.540 --> 00:25:04.520
and what did you know
00:25:04.520 --> 00:25:07.320
and didn't you know and
I could see them doing it
00:25:07.320 --> 00:25:09.170
with this too, so asking students,
00:25:09.170 --> 00:25:12.178
what do you think a fraction is?
00:25:12.178 --> 00:25:15.310
And then how confident
are you in that answer
00:25:15.310 --> 00:25:18.980
and where that fits in would
be interesting to think about,
00:25:18.980 --> 00:25:20.730
yeah, definitely.
00:25:20.730 --> 00:25:25.700
So as you think about advising
teachers on next steps,
00:25:25.700 --> 00:25:28.350
so they've had this conversation,
00:25:28.350 --> 00:25:30.610
what is the next thing they should do
00:25:30.610 --> 00:25:33.053
based on the information that they get?
00:25:34.210 --> 00:25:35.730
- Well, I think as you're listening,
00:25:35.730 --> 00:25:39.000
you're trying to interpret, right?
00:25:39.000 --> 00:25:40.500
What are you noticing?
00:25:40.500 --> 00:25:42.750
Work on those, what do you wanna notice
00:25:42.750 --> 00:25:45.150
with what the student's saying.
00:25:45.150 --> 00:25:50.150
Reflect back on it, the things
that we're putting together
00:25:50.730 --> 00:25:52.080
around these, we've got some videos
00:25:52.080 --> 00:25:56.850
and it's very fun to sit and
watch because you get to,
00:25:56.850 --> 00:25:58.420
if you watch it two or
three times sometimes
00:25:58.420 --> 00:26:01.090
you'll get even more and more out of it.
00:26:01.090 --> 00:26:06.090
So it's, yeah, teachers,
what could you do with these?
00:26:06.825 --> 00:26:09.733
(both laughing)
00:26:09.733 --> 00:26:12.300
I don't know, did I answer that okay or?
00:26:12.300 --> 00:26:14.760
- Yeah, so the idea, it's going to have,
00:26:14.760 --> 00:26:16.220
the teachers are gonna have to do
00:26:16.220 --> 00:26:21.220
some pretty good interpretation
of what they're hearing
00:26:21.360 --> 00:26:24.130
and then think about based on that
00:26:24.130 --> 00:26:29.130
what are the understandings
that they need to either fill in
00:26:29.480 --> 00:26:32.873
or move forward or what that looks like.
00:26:32.873 --> 00:26:37.050
- And it's also self-reflective.
00:26:37.050 --> 00:26:40.460
I mean, when we were putting
these, they made all of us
00:26:40.460 --> 00:26:43.327
stop and think, we had
to sit there and think,
00:26:43.327 --> 00:26:45.467
"Oh, how would we answer this?"
00:26:46.391 --> 00:26:50.000
'Cause basically we weren't
putting questions down
00:26:50.000 --> 00:26:51.330
to get right or wrong answers.
00:26:51.330 --> 00:26:54.590
It's coming up with questions
that uncover thinking
00:26:54.590 --> 00:26:56.490
and you don't have to ask
right or wrong questions
00:26:56.490 --> 00:26:58.240
to uncover thinking.
00:26:58.240 --> 00:27:02.410
- Right, yeah, I think
that's another piece
00:27:02.410 --> 00:27:07.410
in math education that we're
coming to better understandings
00:27:08.330 --> 00:27:11.894
that math education isn't just
about right and wrong answers
00:27:11.894 --> 00:27:12.820
and where things are.
00:27:12.820 --> 00:27:16.263
Math does have right and wrong
answers to some things, but.
00:27:17.655 --> 00:27:21.070
- I'm not minimizing the need
for right or wrong answers.
00:27:21.070 --> 00:27:22.310
But there's a time for that
00:27:22.310 --> 00:27:25.570
and there's a time for
listening to thinking.
00:27:25.570 --> 00:27:29.370
- Yeah, that totally
makes sense, excellent.
00:27:29.370 --> 00:27:31.550
So anything that you're excited about,
00:27:31.550 --> 00:27:32.670
I'll close on this question.
00:27:32.670 --> 00:27:35.210
Anything you're excited about
in the coming couple of months
00:27:35.210 --> 00:27:36.963
that your team work is working on.
00:27:38.011 --> 00:27:43.011
- Oh yeah, so one of the
things I'm working on,
00:27:46.150 --> 00:27:50.270
I just did a talk on this at
South by Southwest last week
00:27:50.270 --> 00:27:53.260
and I called it mathematical rigor mortis,
00:27:53.260 --> 00:27:54.493
the quest for a cure.
00:27:56.146 --> 00:27:59.900
And it's this idea where when we sit back
00:27:59.900 --> 00:28:02.180
and we think about our
field math teachers,
00:28:02.180 --> 00:28:07.000
we think about how many ways
does math kill things, right?
00:28:07.000 --> 00:28:11.073
Math kills dreams, it kills
joy, it kills progress.
00:28:12.762 --> 00:28:15.660
And also it also kills moving policy
00:28:15.660 --> 00:28:16.773
in the right directions
00:28:16.773 --> 00:28:19.980
and making changes at systemic levels.
00:28:19.980 --> 00:28:22.930
This things are so entrenched
in the way that we do things,
00:28:22.930 --> 00:28:24.780
but I'm encouraged and I'm encouraged
00:28:24.780 --> 00:28:27.110
and I hope that the folks
out there are encouraged
00:28:27.110 --> 00:28:29.980
that I think we're moving
in the right direction
00:28:29.980 --> 00:28:32.530
to cure mathematical rigor mortis.
00:28:32.530 --> 00:28:35.780
And if you ever wanna reach
out and talk to me about it,
00:28:35.780 --> 00:28:38.570
I'd love to go into that as well.
00:28:38.570 --> 00:28:40.550
But that's something I'm encouraged about
00:28:40.550 --> 00:28:42.850
is the sort of spaces and the things
00:28:42.850 --> 00:28:45.460
I'm seeing across the
country to help address that.
00:28:45.460 --> 00:28:48.190
- And we had a question
from Angel on YouTube,
00:28:48.190 --> 00:28:51.900
who's a student and wants
to know how they can stay
00:28:51.900 --> 00:28:53.650
motivated when they're doing work.
00:28:53.650 --> 00:28:56.650
We hear this question a lot from folks
00:28:56.650 --> 00:28:58.800
who are needing to stay
motivated to do their work.
00:28:58.800 --> 00:29:00.725
What do you think?
00:29:00.725 --> 00:29:05.725
- Oh, so maybe Angel and
I hope this is helpful
00:29:08.240 --> 00:29:11.820
but if math is being presented to you
00:29:11.820 --> 00:29:14.720
as though it's the
collection of puzzle pieces.
00:29:14.720 --> 00:29:16.100
That you're just shaking the box
00:29:16.100 --> 00:29:17.950
and you can kinda hear them rattling,
00:29:19.643 --> 00:29:20.980
the challenge would be to know that
00:29:20.980 --> 00:29:23.560
it does make a big, beautiful picture,
00:29:23.560 --> 00:29:25.280
that all of the pieces fit together,
00:29:25.280 --> 00:29:27.400
that no piece stands alone.
00:29:27.400 --> 00:29:30.860
And that if you find that encouraging
00:29:30.860 --> 00:29:34.190
then you can figure out how
these pieces fit together,
00:29:34.190 --> 00:29:36.390
what's the story that's being told here.
00:29:36.390 --> 00:29:40.110
It's a great one and
there are lots of places
00:29:40.110 --> 00:29:42.950
where you could go to help get
some support on that as well.
00:29:42.950 --> 00:29:47.950
But don't let the current
situations that you might be in,
00:29:49.170 --> 00:29:53.450
or these things that are
happening all around us right now,
00:29:53.450 --> 00:29:57.490
don't let them destroy the joy
that mathematics has for you.
00:29:57.490 --> 00:29:59.380
That would be my take.
00:29:59.380 --> 00:30:02.010
- I like it and putting
together that puzzle
00:30:02.010 --> 00:30:04.700
could be a challenge, a
fun challenge to undertake
00:30:04.700 --> 00:30:06.470
and to think through, excellent.
00:30:06.470 --> 00:30:09.040
- Yeah, but it's there, it's
ready to be put together,
00:30:09.040 --> 00:30:11.203
but it gets put together in your own head.
00:30:12.370 --> 00:30:15.410
- Fantastic, well thank you
so much for joining us today.
00:30:15.410 --> 00:30:16.950
It was a pleasure to talk to you
00:30:16.950 --> 00:30:19.550
and I hope some of our folks out there
00:30:19.550 --> 00:30:22.260
dive into those conversation starters.
00:30:22.260 --> 00:30:23.960
- Well, thank you, this was great.
|
Sexual and asexual reproduction | https://www.youtube.com/watch?v=IZ6EvH240iA | vtt | https://www.youtube.com/api/timedtext?v=IZ6EvH240iA&ei=wFWUZaarGYOdxgKi0b2ABQ&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245296&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=425465C7046E3A8072EE756C7D893B159BE2A970.3BFA85211A573DDBDDCE61D920A438393099FCEF&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.170 --> 00:00:02.100
- [Narrator] The planet we live on is full
00:00:02.100 --> 00:00:05.150
of life and has been
for billions of years.
00:00:05.150 --> 00:00:07.470
Living things on earth
have existed for as long
00:00:07.470 --> 00:00:11.090
as they have, because life
found a way to create life.
00:00:11.090 --> 00:00:12.520
Sounds crazy, right?
00:00:12.520 --> 00:00:13.840
To put it another way,
00:00:13.840 --> 00:00:16.240
living things found ways to reproduce,
00:00:16.240 --> 00:00:18.220
creating offspring that can then go on
00:00:18.220 --> 00:00:19.910
to reproduce themselves,
00:00:19.910 --> 00:00:22.410
but what exactly is reproduction?
00:00:22.410 --> 00:00:26.160
Well, reproduction is the
process of making new organisms.
00:00:26.160 --> 00:00:28.730
This happens when parent
organisms reproduce
00:00:28.730 --> 00:00:30.330
to form offspring.
00:00:30.330 --> 00:00:31.410
During reproduction,
00:00:31.410 --> 00:00:34.080
organisms pass their genetic information
00:00:34.080 --> 00:00:35.640
on to their offspring.
00:00:35.640 --> 00:00:38.040
This genetic information
provides blueprints
00:00:38.040 --> 00:00:40.760
for how the offspring
will grow and develop
00:00:40.760 --> 00:00:43.800
and it's how traits get
passed on from one generation
00:00:43.800 --> 00:00:44.940
to the next.
00:00:44.940 --> 00:00:48.540
There are two main ways
organisms on earth reproduce.
00:00:48.540 --> 00:00:52.960
This is through asexual
reproduction or sexual reproduction.
00:00:52.960 --> 00:00:56.480
Let's start off by breaking
down asexual reproduction first.
00:00:56.480 --> 00:00:59.870
In asexual reproduction,
only one parent is involved
00:00:59.870 --> 00:01:01.670
in producing offspring.
00:01:01.670 --> 00:01:04.270
Due to this, the
offspring will inherit all
00:01:04.270 --> 00:01:06.930
of their genes from that single parent.
00:01:06.930 --> 00:01:10.420
This means that asexual
reproduction produces offspring
00:01:10.420 --> 00:01:13.240
that are genetically
identical to their parent,
00:01:13.240 --> 00:01:17.200
or in other words, they have
the same collection of genes.
00:01:17.200 --> 00:01:20.190
Various kinds of microorganisms, plants,
00:01:20.190 --> 00:01:23.540
and even animals are able
to reproduce asexually.
00:01:23.540 --> 00:01:25.400
An example of asexual reproduction
00:01:25.400 --> 00:01:28.650
in microorganisms can be seen in bacteria.
00:01:28.650 --> 00:01:31.080
This is due to their
use of a specific type
00:01:31.080 --> 00:01:34.270
of asexual reproduction
called binary fission.
00:01:34.270 --> 00:01:35.450
During this process,
00:01:35.450 --> 00:01:38.800
a single bacteria cell
grows, copies its genes,
00:01:38.800 --> 00:01:41.460
and divides into two identical cells,
00:01:41.460 --> 00:01:43.330
kind of like a copy machine.
00:01:43.330 --> 00:01:45.940
Plants are able to
reproduce asexually too.
00:01:45.940 --> 00:01:48.580
For example, some plants
grow their offspring off
00:01:48.580 --> 00:01:49.870
of themselves.
00:01:49.870 --> 00:01:51.820
In fact, in many succulents,
00:01:51.820 --> 00:01:55.370
you can see baby plants growing
off of their parent plant.
00:01:55.370 --> 00:01:58.430
These babies have the same
genes as their parent plant
00:01:58.430 --> 00:01:59.560
and can grow on their own
00:01:59.560 --> 00:02:01.980
if you remove them and plant them in soil.
00:02:01.980 --> 00:02:03.870
Finally, and interestingly,
00:02:03.870 --> 00:02:06.800
there are various animals
that can reproduce asexually.
00:02:06.800 --> 00:02:10.720
One example is seen in
starfish or sea stars.
00:02:10.720 --> 00:02:12.710
Some species of starfish can split
00:02:12.710 --> 00:02:16.610
into multiple parts that
then grow into new starfish
00:02:16.610 --> 00:02:19.170
and, since they have the same genes,
00:02:19.170 --> 00:02:22.620
each new starfish is a
clone of its original.
00:02:22.620 --> 00:02:25.160
Now that we've covered
asexual reproduction,
00:02:25.160 --> 00:02:27.900
let's move on to sexual reproduction.
00:02:27.900 --> 00:02:30.640
Unlike asexual reproduction,
sexual reproduction
00:02:30.640 --> 00:02:33.530
involves two parents producing
an offspring together
00:02:33.530 --> 00:02:35.070
instead of one.
00:02:35.070 --> 00:02:36.010
This is important
00:02:36.010 --> 00:02:38.510
because it means that the
offspring will inherit half
00:02:38.510 --> 00:02:40.160
of their genes from one parent
00:02:40.160 --> 00:02:42.820
and half of their genes from the other.
00:02:42.820 --> 00:02:46.230
Because of this, a sexual
reproduction produces offspring
00:02:46.230 --> 00:02:47.980
that are genetically distinct
00:02:47.980 --> 00:02:49.250
or have a different combination
00:02:49.250 --> 00:02:51.830
of genes compared to either parent.
00:02:51.830 --> 00:02:54.740
With this, because of the
way the genes are passed on,
00:02:54.740 --> 00:02:56.690
there are tons of different combinations
00:02:56.690 --> 00:02:59.960
of genes that can be received
from the two parents.
00:02:59.960 --> 00:03:01.560
In other words, this means
00:03:01.560 --> 00:03:05.210
that sexual reproduction creates
offspring that show a lot
00:03:05.210 --> 00:03:08.450
of genetic variation
between their siblings.
00:03:08.450 --> 00:03:09.880
To better understand this,
00:03:09.880 --> 00:03:11.640
let's take a look at my own dogs.
00:03:11.640 --> 00:03:12.720
They're brother and sister,
00:03:12.720 --> 00:03:15.660
so they share the same
parents, which I've drawn here.
00:03:15.660 --> 00:03:18.560
As you've probably noticed,
my dogs look pretty different
00:03:18.560 --> 00:03:19.490
from each other.
00:03:19.490 --> 00:03:22.410
One of the most notable
differences though is how one
00:03:22.410 --> 00:03:24.910
of them received genes from this parent
00:03:24.910 --> 00:03:26.780
that gave them markings above their eyes
00:03:26.780 --> 00:03:30.250
that kind of looked like
eyebrows while the other did not.
00:03:30.250 --> 00:03:32.480
And while it's easy to
spot genetic differences,
00:03:32.480 --> 00:03:34.100
like my dog's eyebrows,
00:03:34.100 --> 00:03:38.030
genetic variation goes
way deeper than dog's fur.
00:03:38.030 --> 00:03:40.700
It's what makes sexual
reproduced organisms
00:03:40.700 --> 00:03:43.020
genetically distinct from each other
00:03:43.020 --> 00:03:46.160
and gives the building
blocks to who they are.
00:03:46.160 --> 00:03:48.340
And with that, you now know the difference
00:03:48.340 --> 00:03:51.390
between asexual and sexual reproduction.
00:03:51.390 --> 00:03:54.310
Let's do a quick overview of
what you've learned today.
00:03:54.310 --> 00:03:57.230
Living organisms reproduce
to create offspring
00:03:57.230 --> 00:04:00.770
through either asexual
or sexual reproduction.
00:04:00.770 --> 00:04:03.870
Asexual reproduction
involves only one parent
00:04:03.870 --> 00:04:07.900
meaning the parent and offspring
will have identical genes.
00:04:07.900 --> 00:04:10.850
Sexual reproduction involves two parents
00:04:10.850 --> 00:04:13.750
and results in offspring
that are genetically unique
00:04:13.750 --> 00:04:16.230
compared to either
parent and this all goes
00:04:16.230 --> 00:04:18.620
to show how fantastically unique life
00:04:18.620 --> 00:04:19.930
on earth is.
00:04:19.930 --> 00:04:21.600
Though organisms may differ
00:04:21.600 --> 00:04:23.860
in the ways that they've
been able to reproduce
00:04:23.860 --> 00:04:25.070
as seen in the examples
00:04:25.070 --> 00:04:29.300
between bacteria, succulents,
starfish, and dogs,
00:04:29.300 --> 00:04:32.370
these organisms, as
with all living things,
00:04:32.370 --> 00:04:35.160
share the ability to create more life
00:04:35.160 --> 00:04:36.830
just as all life has shared
00:04:36.830 --> 00:04:39.153
for billions of years here on this planet.
|
Organism growth and the environment | https://www.youtube.com/watch?v=XEkafr12Wd8 | vtt | https://www.youtube.com/api/timedtext?v=XEkafr12Wd8&ei=wFWUZbjuKu-2mLAPlJaZ6Ak&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245296&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=D59D46B9CF770D59FE307B25F455874355E311.7C3C3190464BB9BFB39D3D80DD4A3D31BC65455F&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.400 --> 00:00:01.760
- [Instructor] Hey, have you ever seen
00:00:01.760 --> 00:00:03.120
this kind of plant before?
00:00:03.120 --> 00:00:04.660
It's called a dandelion.
00:00:04.660 --> 00:00:07.970
If you live in a tropical
climate, it might be unfamiliar,
00:00:07.970 --> 00:00:10.010
but if you live in a more temperate zone,
00:00:10.010 --> 00:00:13.080
you'll probably recognize it
as it's a very common plant.
00:00:13.080 --> 00:00:16.410
Dandelions make yellow flowers
that develop into balls
00:00:16.410 --> 00:00:19.990
of these fluffy white seed
heads that fly off the plant.
00:00:19.990 --> 00:00:22.070
This can happen by a gust of wind,
00:00:22.070 --> 00:00:23.560
by animals spreading them,
00:00:23.560 --> 00:00:26.180
or even by someone blowing on the plant.
00:00:26.180 --> 00:00:28.750
When this happens, it
seeds fly into the air
00:00:28.750 --> 00:00:31.430
and land on new spots on the ground.
00:00:31.430 --> 00:00:34.140
From there, the seeds can
grow into new dandelions,
00:00:34.140 --> 00:00:36.720
starting the whole cycle over.
00:00:36.720 --> 00:00:39.180
But why do dandelions do this?
00:00:39.180 --> 00:00:41.330
Why do they turn into puff balls?
00:00:41.330 --> 00:00:43.010
Why are they yellow?
00:00:43.010 --> 00:00:44.700
If they don't have brains,
00:00:44.700 --> 00:00:48.320
how do they seem to know
when to release their seeds?
00:00:48.320 --> 00:00:51.140
These are all complicated questions.
00:00:51.140 --> 00:00:53.090
But to begin answering them,
00:00:53.090 --> 00:00:56.440
we can talk about what influences
the growth and development
00:00:56.440 --> 00:01:00.670
of dandelions and in
turn all living things.
00:01:00.670 --> 00:01:04.110
So what determines how
a dandelion will grow?
00:01:04.110 --> 00:01:07.070
Its genes and its environment.
00:01:07.070 --> 00:01:09.980
Let's take a moment to
review what genes are.
00:01:09.980 --> 00:01:12.370
Genes make up the hereditary material
00:01:12.370 --> 00:01:14.540
inside an organism cells.
00:01:14.540 --> 00:01:16.170
Genes provide the information
00:01:16.170 --> 00:01:18.510
about what traits an organism has.
00:01:18.510 --> 00:01:22.490
So the reason that our
dandelion has yellow pedals
00:01:22.490 --> 00:01:24.640
and develops fluffy white seed heads
00:01:24.640 --> 00:01:27.040
lies within its genes.
00:01:27.040 --> 00:01:30.450
Any influence genes have on
the way an organism grows
00:01:30.450 --> 00:01:32.550
is called a genetic factor.
00:01:32.550 --> 00:01:35.750
So if one dandelion has
more seeds than another
00:01:35.750 --> 00:01:39.320
as a result of which version
of a certain gene it has,
00:01:39.320 --> 00:01:41.450
we can say that the
difference in seed number
00:01:41.450 --> 00:01:43.780
is due to a genetic factor.
00:01:43.780 --> 00:01:46.800
The other major influence
on how a dandelion grows
00:01:46.800 --> 00:01:48.510
is its environment.
00:01:48.510 --> 00:01:51.280
But what makes up an
organism's environment?
00:01:51.280 --> 00:01:53.410
The environment is the set of conditions
00:01:53.410 --> 00:01:56.610
an organism is exposed to during its life.
00:01:56.610 --> 00:01:59.100
For a dandelion, this
includes temperature,
00:01:59.100 --> 00:02:01.460
how much light and water it gets,
00:02:01.460 --> 00:02:03.900
and which nutrients
are present in the soil
00:02:03.900 --> 00:02:05.330
where it grows.
00:02:05.330 --> 00:02:09.310
Any influence the environment
has on an organism's growth
00:02:09.310 --> 00:02:11.990
is called an environmental factor.
00:02:11.990 --> 00:02:15.520
So if one dandelion plant
is exposed to more sunlight
00:02:15.520 --> 00:02:18.750
than another and grows
bigger, as a result,
00:02:18.750 --> 00:02:20.720
we can say that the difference is due
00:02:20.720 --> 00:02:23.310
to an environmental factor.
00:02:23.310 --> 00:02:25.750
But plants aren't the
only living organisms
00:02:25.750 --> 00:02:28.230
that are motivated by these factors.
00:02:28.230 --> 00:02:32.540
Animals are also influenced by
their genes and environment.
00:02:32.540 --> 00:02:34.900
For example, let's look at dogs.
00:02:34.900 --> 00:02:38.810
Dogs come in many different
shapes, sizes, colors,
00:02:38.810 --> 00:02:41.410
and each have their own unique features.
00:02:41.410 --> 00:02:43.870
We can see this when
looking at different breeds,
00:02:43.870 --> 00:02:47.130
like pugs which are
small with squishy faces,
00:02:47.130 --> 00:02:48.410
and golden retrievers,
00:02:48.410 --> 00:02:52.010
which are large with
flowing locks of golden fur.
00:02:52.010 --> 00:02:53.980
These traits are largely determined
00:02:53.980 --> 00:02:56.680
by which genes each breed of dog has,
00:02:56.680 --> 00:03:00.380
or in other words, by genetic factors.
00:03:00.380 --> 00:03:04.360
But dogs are also influenced
by environmental factors too.
00:03:04.360 --> 00:03:07.180
For instance, how much
food they get as they grow
00:03:07.180 --> 00:03:09.170
helps determine their size,
00:03:09.170 --> 00:03:11.420
and what they learn from other dogs,
00:03:11.420 --> 00:03:14.390
and from people help
determine their behaviors.
00:03:14.390 --> 00:03:17.200
Like when you teach your dog a new trick.
00:03:17.200 --> 00:03:19.570
And now you know how
organisms are influenced
00:03:19.570 --> 00:03:21.440
by genetics and their environment
00:03:21.440 --> 00:03:24.210
when it comes to growth and development.
00:03:24.210 --> 00:03:27.130
Let's do a quick review of
what you've learned today.
00:03:27.130 --> 00:03:29.040
First, there are two main factors
00:03:29.040 --> 00:03:31.300
that influence an organism's growth,
00:03:31.300 --> 00:03:35.000
these are genetic and
environmental factors.
00:03:35.000 --> 00:03:38.010
Genetic factors are the
genes the organism gets
00:03:38.010 --> 00:03:40.090
from its parent or parents.
00:03:40.090 --> 00:03:42.477
While environmental
factors are the conditions
00:03:42.477 --> 00:03:46.080
and organism is exposed to as it grows.
00:03:46.080 --> 00:03:48.600
These factors show that
all living organisms
00:03:48.600 --> 00:03:53.040
have a couple things in common
even dogs and dandelions.
00:03:53.040 --> 00:03:55.610
So while our interactions
with them may differ
00:03:55.610 --> 00:03:58.020
like how you can't
teach a dandelion to sit
00:03:58.020 --> 00:03:59.900
like you can with a dog,
00:03:59.900 --> 00:04:02.810
both organisms experience
growth and development
00:04:02.810 --> 00:04:05.483
through their own unique
genes and environments.
|
Sensory processing and the brain | https://www.youtube.com/watch?v=fMrz3L9bMsI | vtt | https://www.youtube.com/api/timedtext?v=fMrz3L9bMsI&ei=wFWUZdyFOY6QhcIPtNCz-A0&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245297&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=AB8E89C1040806E0709EC53FB2A769470B6A2733.8089C447011EA74B26B12FBC2BF6532F93CB1107&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.200 --> 00:00:02.070
- [Narrator] As humans,
we have a lot of senses
00:00:02.070 --> 00:00:04.920
that we put to use on a regular basis.
00:00:04.920 --> 00:00:09.500
They include sight, smell,
taste, touch, and hearing.
00:00:09.500 --> 00:00:12.640
But have you ever
wondered how it all works?
00:00:12.640 --> 00:00:15.940
How do you look at a beautiful
painting in an art museum,
00:00:15.940 --> 00:00:18.840
or smell the rain outside on a stormy day,
00:00:18.840 --> 00:00:20.660
or feel that your favorite pair of socks
00:00:20.660 --> 00:00:22.510
are still a little damp,
00:00:22.510 --> 00:00:25.120
and need another cycle in the dryer?
00:00:25.120 --> 00:00:27.180
How does that information make its way
00:00:27.180 --> 00:00:30.240
from our sensory organs to our brains?
00:00:30.240 --> 00:00:33.580
Well, the answer lies
in the nervous system.
00:00:33.580 --> 00:00:35.284
If you remember, our bodies are made up
00:00:35.284 --> 00:00:38.800
of multiple complex organ
systems that work together
00:00:38.800 --> 00:00:41.910
to perform all different
kinds of functions.
00:00:41.910 --> 00:00:45.070
Today, let's talk specifically
about the nervous system,
00:00:45.070 --> 00:00:46.820
which is an organ system that allows us
00:00:46.820 --> 00:00:50.540
to sense and respond to our environment.
00:00:50.540 --> 00:00:53.341
To begin, the nervous system
contains specialized cells
00:00:53.341 --> 00:00:56.550
and cell parts, called sensory receptors,
00:00:56.550 --> 00:00:59.610
which are able to pick up
signals from the environment.
00:00:59.610 --> 00:01:01.760
These signals are called stimuli,
00:01:01.760 --> 00:01:04.970
or stimulus if you're
talking about just one.
00:01:04.970 --> 00:01:07.890
Stimuli can come in many different forms.
00:01:07.890 --> 00:01:11.820
For instance, mechanical
stimuli are physical in nature,
00:01:11.820 --> 00:01:15.570
and are involved with our
senses of touch and hearing.
00:01:15.570 --> 00:01:16.910
You can strum a guitar,
00:01:16.910 --> 00:01:19.360
feeling the strings
against your fingertips,
00:01:19.360 --> 00:01:21.900
and listening to the
unique tones it produces
00:01:21.900 --> 00:01:23.600
as the strings vibrate.
00:01:23.600 --> 00:01:26.430
Those are all mechanical stimuli.
00:01:26.430 --> 00:01:28.900
Chemical stimuli are made up of molecules,
00:01:28.900 --> 00:01:32.390
and are involved with our
senses of smell and taste.
00:01:32.390 --> 00:01:34.020
To illustrate an example,
00:01:34.020 --> 00:01:37.860
imagine eating a tasty bowl
of chicken noodle soup.
00:01:37.860 --> 00:01:40.500
As you spoon mouthfuls
of soup into your mouth,
00:01:40.500 --> 00:01:42.634
your taste and olfactory receptors
00:01:42.634 --> 00:01:44.234
are flooded with molecules
00:01:44.234 --> 00:01:47.690
that signal the qualities
of the food you're eating.
00:01:47.690 --> 00:01:50.610
These molecular signals
are chemical stimuli.
00:01:50.610 --> 00:01:51.810
And in this case,
00:01:51.810 --> 00:01:53.680
the molecules from the chicken noodle soup
00:01:53.680 --> 00:01:56.410
convey that the food
you're eating is savory,
00:01:56.410 --> 00:01:58.800
and extremely delicious.
00:01:58.800 --> 00:02:01.220
Lastly, electromagnetic stimuli
00:02:01.220 --> 00:02:02.950
are involved with our sense of sight,
00:02:02.950 --> 00:02:06.140
and include the light that
comes into our eyes every day.
00:02:06.140 --> 00:02:08.070
The sunlight that makes you squint,
00:02:08.070 --> 00:02:10.600
the traffic lights you see on the street,
00:02:10.600 --> 00:02:13.520
and the vibrant and diverse
colors all around you.
00:02:13.520 --> 00:02:14.762
These are just a few examples
00:02:14.762 --> 00:02:18.660
of electromagnetic stimuli
in the form of light.
00:02:18.660 --> 00:02:23.210
So then what happens after
sensory receptors detect stimuli?
00:02:23.210 --> 00:02:26.410
Well, once a sensory receptor
receives the information,
00:02:26.410 --> 00:02:29.430
it passes this information
along nerve cells.
00:02:29.430 --> 00:02:31.440
Here's a picture of a nerve cell,
00:02:31.440 --> 00:02:33.313
which is specialized
to transmit information
00:02:33.313 --> 00:02:36.300
in the form of electrical signals.
00:02:36.300 --> 00:02:39.420
These signals are transmitted
along nerves to the brain,
00:02:39.420 --> 00:02:41.710
which is then responsible for processing,
00:02:41.710 --> 00:02:43.740
or organizing sensory information
00:02:43.740 --> 00:02:46.100
from different sensory receptors.
00:02:46.100 --> 00:02:48.080
After processing the information,
00:02:48.080 --> 00:02:49.407
the brain can elicit a response,
00:02:49.407 --> 00:02:52.610
and also store the information
in the form of a memory
00:02:52.610 --> 00:02:54.140
for future use.
00:02:54.140 --> 00:02:55.940
For example, imagine you're playing catch
00:02:55.940 --> 00:02:57.830
with friends in a park.
00:02:57.830 --> 00:02:59.829
Your sensory receptors pick up information
00:02:59.829 --> 00:03:02.470
as you watch the ball come towards you,
00:03:02.470 --> 00:03:04.670
and feel the wind on your skin.
00:03:04.670 --> 00:03:05.758
Signals from these receptors
00:03:05.758 --> 00:03:08.670
travel along nerve cells to your brain,
00:03:08.670 --> 00:03:11.640
where all these different
signals are organized.
00:03:11.640 --> 00:03:13.640
Then your brain elicits a response,
00:03:13.640 --> 00:03:16.040
such as moving to just the right spot,
00:03:16.040 --> 00:03:18.370
and putting your hands
out to catch the ball.
00:03:18.370 --> 00:03:20.640
And the brain also stores a memory,
00:03:20.640 --> 00:03:22.260
perhaps remembering playing catch
00:03:22.260 --> 00:03:25.810
as a fun activity that
you'd wanna do again.
00:03:25.810 --> 00:03:27.821
You can almost think of
this flow of information
00:03:27.821 --> 00:03:31.670
from a stimulus to sensing, to processing,
00:03:31.670 --> 00:03:35.230
and finally, to eliciting a
response or storing information,
00:03:35.230 --> 00:03:37.660
like a complex relay race.
00:03:37.660 --> 00:03:41.400
Sensory receptors pick up
message in the form of stimuli,
00:03:41.400 --> 00:03:45.110
and pass this information along
to nerves, and to the brain.
00:03:45.110 --> 00:03:47.522
Only in this relay, the end
result at the finish line
00:03:47.522 --> 00:03:51.630
is a response to the stimulus
and information storage.
00:03:51.630 --> 00:03:52.760
So to summarize,
00:03:52.760 --> 00:03:55.270
today, we talked about
how our bodies sense,
00:03:55.270 --> 00:03:57.210
and respond to the environment.
00:03:57.210 --> 00:04:00.110
Information is transferred from a stimulus
00:04:00.110 --> 00:04:02.880
to a sensory receptor, to nerve cells,
00:04:02.880 --> 00:04:06.350
and finally to the brain,
where processing occurs.
00:04:06.350 --> 00:04:08.210
Whether we're aware of it or not,
00:04:08.210 --> 00:04:12.400
our nervous system is working
at rapid-fire speed every day
00:04:12.400 --> 00:04:14.170
to provide us with the information
00:04:14.170 --> 00:04:16.810
our bodies need to sense
what's in our environment,
00:04:16.810 --> 00:04:18.223
and thrive in it.
|
Writing fraction division story problems | https://www.youtube.com/watch?v=UEna8ZEy6k4 | vtt | https://www.youtube.com/api/timedtext?v=UEna8ZEy6k4&ei=wFWUZdHBMoqhp-oP7paXIA&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245296&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=19CB28FD3D9EB39190D52AFF8A41FEDF48BB3E25.462C61F7C3993E5E74B0988DDCC7479F6B7B6DA4&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.180 --> 00:00:04.100
- [Instructor] We're told
that Darryl spent 24 1/4 hours
00:00:04.100 --> 00:00:06.610
writing a chapter of a novel.
00:00:06.610 --> 00:00:11.090
And then they ask us, what
are some things that 24 1/4
00:00:11.090 --> 00:00:16.090
divided by 3/4 could
represent in this context?
00:00:16.290 --> 00:00:18.090
So my understanding of this
00:00:18.090 --> 00:00:21.280
is they really just want us
to be a little bit creative
00:00:21.280 --> 00:00:24.610
about what division by a fraction
00:00:24.610 --> 00:00:28.270
could represent in a given context.
00:00:28.270 --> 00:00:31.190
So, well, one, I encourage
you to pause your video
00:00:31.190 --> 00:00:34.100
and think about that a little
bit before I think about it.
00:00:34.100 --> 00:00:39.100
But one thing I think about
is, well, if I took 24 1/4,
00:00:39.340 --> 00:00:43.280
and if I were to divide it
into chunks of 3/4 of an hour
00:00:43.280 --> 00:00:47.140
because this is in hours,
how many chunks would I have?
00:00:47.140 --> 00:00:52.080
So this could represent,
let's say that he spent,
00:00:52.080 --> 00:00:55.280
he spent 45 minutes,
00:00:55.280 --> 00:00:57.140
which is the same thing of 3/4 of an hour,
00:00:57.140 --> 00:01:00.950
3/4 hours, of an hour, I should say,
00:01:00.950 --> 00:01:05.950
3/4 of an hour each day.
00:01:08.710 --> 00:01:13.710
How many days, how many days
did it take him, did it take?
00:01:19.990 --> 00:01:24.670
And then you could evaluate
this, 24 1/4 divided by 3/4.
00:01:24.670 --> 00:01:27.480
We've talked about how to
evaluate that in other videos.
00:01:27.480 --> 00:01:29.270
So that's one context.
00:01:29.270 --> 00:01:34.270
Another one could be some
type of a comparison.
00:01:34.470 --> 00:01:36.520
So let's say that 24 1/4
00:01:36.520 --> 00:01:41.250
is 3/4 of the amount of time
00:01:41.250 --> 00:01:43.950
that he spent doing something else.
00:01:43.950 --> 00:01:47.630
So let's say, so this is now a
completely different context.
00:01:47.630 --> 00:01:48.640
I'm gonna put a line here.
00:01:48.640 --> 00:01:50.460
I'll do it in a different
color just to make it clear
00:01:50.460 --> 00:01:52.030
it's a different context.
00:01:52.030 --> 00:01:55.860
So another one could be to
justify doing this division,
00:01:55.860 --> 00:02:00.720
he spent 3/4 as long writing,
00:02:03.230 --> 00:02:08.230
writing as he spent illustrating,
00:02:10.120 --> 00:02:12.713
illustrating the chapter.
00:02:14.390 --> 00:02:15.630
And so then the question
00:02:15.630 --> 00:02:18.380
is how long did he spend illustrating?
00:02:18.380 --> 00:02:23.380
How long did he spend illustrating?
00:02:27.510 --> 00:02:29.030
Now, I really want you
to think about this one.
00:02:29.030 --> 00:02:31.900
My brain, actually, this one
takes a little bit longer
00:02:31.900 --> 00:02:34.280
for my brain to process.
00:02:34.280 --> 00:02:35.240
But when you think about it,
00:02:35.240 --> 00:02:38.280
if you divide by a fraction
that is less than one,
00:02:38.280 --> 00:02:39.700
you're gonna get a number larger
00:02:39.700 --> 00:02:41.600
than the one that you're dealing with.
00:02:41.600 --> 00:02:43.410
Or another way to think about it,
00:02:43.410 --> 00:02:47.600
the time spent illustrating,
time illustrating,
00:02:47.600 --> 00:02:48.870
I'll write it like this,
00:02:48.870 --> 00:02:52.330
the time illustrating times 3/4
00:02:52.330 --> 00:02:55.030
should be equal to the time spent writing
00:02:55.030 --> 00:02:57.280
because it says he spent,
00:02:57.280 --> 00:03:00.110
or he spent, I forgot to write that,
00:03:00.110 --> 00:03:03.550
he spent 3/4 as long writing
as he spent illustrating.
00:03:03.550 --> 00:03:05.430
So time illustrating times 3/4
00:03:05.430 --> 00:03:08.810
should be time writing or 24 1/4.
00:03:08.810 --> 00:03:12.530
So if something times
3/4 is equal to 24 1/4,
00:03:12.530 --> 00:03:17.530
then 24 1/4 divided by 3/4
00:03:18.090 --> 00:03:23.090
should be equal to time illustrating.
00:03:23.710 --> 00:03:26.240
So these are the two
contexts that I can think of
00:03:26.240 --> 00:03:27.170
that might make sense,
00:03:27.170 --> 00:03:29.220
but you might be able to think of others.
|
Area with fraction division example | https://www.youtube.com/watch?v=6K6tQulp-x8 | vtt | https://www.youtube.com/api/timedtext?v=6K6tQulp-x8&ei=wVWUZfHWA4fpxN8PntuTyAE&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245297&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=C263D90BEB4D9D5981DD9CB6DAFFB530FD86C4EE.C5ECE4354AD790A151A4A6003A94D66922760518&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.540 --> 00:00:02.840
- [Instructor] We're told a
yoga mat is 3/5 of a meter wide.
00:00:02.840 --> 00:00:06.620
It has an area of 1
and 2/25 square meters.
00:00:06.620 --> 00:00:09.250
What is the length of the mat?
00:00:09.250 --> 00:00:12.100
Well, we know that length times width
00:00:12.100 --> 00:00:14.260
is going to give you area,
00:00:14.260 --> 00:00:16.070
or another way of thinking about it,
00:00:16.070 --> 00:00:19.040
if the product of two numbers
gives you a third number,
00:00:19.040 --> 00:00:20.170
if you take that third number
00:00:20.170 --> 00:00:21.720
and divide it by one of these,
00:00:21.720 --> 00:00:22.700
you're going to get the other one.
00:00:22.700 --> 00:00:23.770
So another way of thinking about it
00:00:23.770 --> 00:00:28.770
is length would be the same
thing as area divided by width.
00:00:29.460 --> 00:00:32.200
So we're trying to figure
out the length here.
00:00:32.200 --> 00:00:34.550
We have the area, we have the width.
00:00:34.550 --> 00:00:37.980
So our length is going to be 1 and 2/25,
00:00:37.980 --> 00:00:42.980
1 and 2/25 divided by 3/5.
00:00:44.730 --> 00:00:46.970
Now this is going to be the same thing as,
00:00:46.970 --> 00:00:49.320
let me write this as an improper fraction,
00:00:49.320 --> 00:00:52.430
it's gonna be easier to do
some arithmetic with it.
00:00:52.430 --> 00:00:57.430
So one is the same thing
as 25/25, plus 2/25,
00:00:58.030 --> 00:01:03.030
this is 27/25 divided by 3/5.
00:01:05.630 --> 00:01:07.590
And we've already talked
about how this is saying
00:01:07.590 --> 00:01:11.250
how many 3/5 can fit into 27/25.
00:01:11.250 --> 00:01:13.860
And we've given the intuition
why this is the same thing
00:01:13.860 --> 00:01:18.860
as just multiplying 27/25
times the reciprocal of 3/5,
00:01:21.030 --> 00:01:24.230
which is 5/3.
00:01:24.230 --> 00:01:26.270
And so this is going to be equal to,
00:01:26.270 --> 00:01:28.300
and actually I'm gonna
factor this out a little bit
00:01:28.300 --> 00:01:30.340
to simplify things a bit.
00:01:30.340 --> 00:01:34.110
27 is 3 x 3 x 3.
00:01:34.110 --> 00:01:36.910
25 is 5 x 5.
00:01:36.910 --> 00:01:38.120
So this is going to be equal to,
00:01:38.120 --> 00:01:40.980
in our numerator we're
gonna have 3 x 3 x 3 x 5.
00:01:40.980 --> 00:01:45.250
3 x 3 x 3 x 5.
00:01:45.250 --> 00:01:49.220
And then in our denominator
we're gonna have 5 x 5 x 3.
00:01:49.220 --> 00:01:52.290
5 x 5 x 3.
00:01:52.290 --> 00:01:55.310
And then we can reduce this a little bit.
00:01:55.310 --> 00:01:56.670
We can divide both the numerator
00:01:56.670 --> 00:01:58.180
and the denominator by five.
00:01:58.180 --> 00:01:59.470
We can divide both the numerator
00:01:59.470 --> 00:02:01.290
and the denominator by three.
00:02:01.290 --> 00:02:06.290
So in the numerator, we're
gonna 3 x 3, which is 9/5.
00:02:06.680 --> 00:02:09.820
So this is all going to be equal to 9/5.
00:02:09.820 --> 00:02:13.380
So the yoga mat is 3/5 of a meter wide
00:02:13.380 --> 00:02:16.690
and 9/5 of a meter long.
00:02:16.690 --> 00:02:19.320
Now let's make sure that this makes sense.
00:02:19.320 --> 00:02:21.030
So I'm gonna make a grid.
00:02:21.030 --> 00:02:26.030
So this right over here is 1/5 of a meter.
00:02:26.998 --> 00:02:29.050
1/5 of a meter in that dimension
00:02:29.050 --> 00:02:33.600
and 1/5 of a meter in that dimension.
00:02:33.600 --> 00:02:38.600
And then we can see, well,
if this is 1/5 of a meter,
00:02:38.840 --> 00:02:43.840
then the width right over
here is 3/5 of a meter.
00:02:44.125 --> 00:02:47.810
Our length right over
here, we have 1, 2, 3, 4,
00:02:47.810 --> 00:02:50.670
5, 6, 7, 8, 9, fifths.
00:02:50.670 --> 00:02:52.780
It is 9/5.
00:02:52.780 --> 00:02:56.900
Now each of these units, what is its area?
00:02:56.900 --> 00:03:01.750
Well, it is 1/25 meter squared.
00:03:01.750 --> 00:03:03.530
And how many of these do we have?
00:03:03.530 --> 00:03:07.810
Well, we can see, we
have three rows of nine,
00:03:07.810 --> 00:03:11.350
which is 27 of these 25ths,
00:03:11.350 --> 00:03:14.280
so we're gonna have 27/25 square meters,
00:03:14.280 --> 00:03:17.833
which is the same thing as
1 and 2/5 square meters.
|
Decimal multiplication place value | https://www.youtube.com/watch?v=hdKDVDjUHhs | vtt | https://www.youtube.com/api/timedtext?v=hdKDVDjUHhs&ei=xFWUZYDAFNSDxs0P_-SsiAQ&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245300&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=E1B00C26DD019A08A79300CAF308044DB2FF3ED6.DD095077C7BD17C8458FBA5B0CCD1D76F76CEF1B&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.620 --> 00:00:02.280
- [Instructor] This is an
exercise from Khan Academy.
00:00:02.280 --> 00:00:04.750
It tells us that the product 75 times 61
00:00:04.750 --> 00:00:08.110
is equal to 4,575.
00:00:08.110 --> 00:00:10.545
Use a previous fact to
evaluate as a decimal.
00:00:10.545 --> 00:00:11.734
This right over here,
00:00:11.734 --> 00:00:15.900
7.5 times 0.061.
00:00:15.900 --> 00:00:19.110
Pause this video and see
if you can have a go at it.
00:00:19.110 --> 00:00:21.280
All right, now let's do this together.
00:00:21.280 --> 00:00:23.110
So the first thing that you might realize
00:00:23.110 --> 00:00:28.110
is that 7.5 is the same thing as 75
00:00:28.290 --> 00:00:31.770
divided by 10.
00:00:31.770 --> 00:00:33.890
And 0.061,
00:00:33.890 --> 00:00:37.010
this is 61 thousandths.
00:00:37.010 --> 00:00:42.010
This right over here
is the same thing as 61
00:00:42.180 --> 00:00:45.770
divided by 1,000
00:00:45.770 --> 00:00:49.140
and we're gonna take the
product of these two things.
00:00:49.140 --> 00:00:51.530
Another way we could write this,
00:00:51.530 --> 00:00:53.540
75 divided by 10,
00:00:53.540 --> 00:00:54.450
this is the same thing
00:00:54.450 --> 00:00:57.490
as 75 over 10
00:00:57.490 --> 00:00:59.100
and I'm gonna take the product of that,
00:00:59.100 --> 00:01:03.490
and 61 thousandths, 61 divided by 1,000.
00:01:03.490 --> 00:01:08.490
So that would be 61/1,000.
00:01:09.130 --> 00:01:10.240
Now, when we look at it,
00:01:10.240 --> 00:01:11.380
either of these ways,
00:01:11.380 --> 00:01:13.430
well actually, I'll do both
of them at the same time.
00:01:13.430 --> 00:01:14.430
You could change the order
00:01:14.430 --> 00:01:16.120
of the multiplication
and the division here.
00:01:16.120 --> 00:01:19.800
So you could start with 75 times 61,
00:01:19.800 --> 00:01:22.760
75 times 61,
00:01:22.760 --> 00:01:24.923
and then divide that by 10,
00:01:26.160 --> 00:01:29.790
and then divide that by 1,000.
00:01:29.790 --> 00:01:32.020
You could do it that way
00:01:32.020 --> 00:01:34.130
or you could look right over here
00:01:34.130 --> 00:01:35.380
and say, all right,
00:01:35.380 --> 00:01:36.820
if I'm taking this product,
00:01:36.820 --> 00:01:39.970
my numerator is going to be 75 times 61,
00:01:39.970 --> 00:01:42.230
75 times 61.
00:01:42.230 --> 00:01:44.690
And then, my denominator
00:01:44.690 --> 00:01:48.000
is going to be 10 times 1,000
00:01:48.000 --> 00:01:49.380
which is essentially the same thing
00:01:49.380 --> 00:01:51.210
as dividing by 10,
00:01:51.210 --> 00:01:53.170
and then dividing by 1,000.
00:01:53.170 --> 00:01:57.220
And of course, that is going to be 10,000.
00:01:57.220 --> 00:02:00.900
Now on the left-hand
side, right over here,
00:02:00.900 --> 00:02:04.420
they told us what this is, it's 4,575.
00:02:04.420 --> 00:02:05.440
So it's 4,575
00:02:07.590 --> 00:02:08.920
divided by 10,
00:02:08.920 --> 00:02:10.310
and then divided by 1,000.
00:02:10.310 --> 00:02:11.470
Well, if I divide by 10,
00:02:11.470 --> 00:02:13.150
and then I divide by 1,000,
00:02:13.150 --> 00:02:17.240
that's equivalent to dividing by 10,000.
00:02:17.240 --> 00:02:21.303
This is dividing by 10,000
00:02:22.480 --> 00:02:23.530
and you could see that over here.
00:02:23.530 --> 00:02:25.140
We're dividing by 10,000
00:02:25.140 --> 00:02:26.480
as well right over here.
00:02:26.480 --> 00:02:29.040
And the 75 times 61,
00:02:29.040 --> 00:02:32.850
this is 4,575.
00:02:32.850 --> 00:02:35.130
Now they want us to
evaluate it as a decimal.
00:02:35.130 --> 00:02:37.080
We've now expressed it as a fraction
00:02:37.080 --> 00:02:39.720
and I still haven't
fully evaluated this yet.
00:02:39.720 --> 00:02:41.030
So we really wanna think
00:02:41.030 --> 00:02:44.631
about this as 4,575 ten thousandths
00:02:44.631 --> 00:02:46.630
and you can see that very explicitly here.
00:02:46.630 --> 00:02:50.350
There's 4,575 ten thousandths.
00:02:50.350 --> 00:02:52.260
So how do we write that?
00:02:52.260 --> 00:02:55.680
Well, if I have a decimal right over here,
00:02:55.680 --> 00:02:57.450
that's the tenths place.
00:02:57.450 --> 00:02:59.510
This is the hundredths,
00:02:59.510 --> 00:03:02.820
thousandths, ten-thousandths place.
00:03:02.820 --> 00:03:05.140
So we have this many ten thousandths,
00:03:05.140 --> 00:03:09.410
4,575 ten thousandths
00:03:10.290 --> 00:03:11.300
and we're done.
00:03:11.300 --> 00:03:16.193
So this is gonna be 0.4575.
00:03:16.193 --> 00:03:19.360
Now I know what some of
you might be thinking.
00:03:19.360 --> 00:03:21.700
Hey, I learned a technique
00:03:21.700 --> 00:03:23.710
where if I'm taking the
product of two numbers,
00:03:23.710 --> 00:03:25.790
I could take the product
of those two numbers,
00:03:25.790 --> 00:03:27.020
or if I'm taking the
product of two numbers
00:03:27.020 --> 00:03:28.260
that are decimals,
00:03:28.260 --> 00:03:31.280
I could remove the decimals
from them essentially,
00:03:31.280 --> 00:03:32.140
take their product
00:03:32.140 --> 00:03:34.240
which they actually
gave us right over here.
00:03:34.240 --> 00:03:36.360
And then, count how
many digits to the right
00:03:36.360 --> 00:03:38.540
of the decimal there were
in our original numbers.
00:03:38.540 --> 00:03:42.190
So we have one, two, three,
00:03:42.190 --> 00:03:46.410
four digits to the right of the decimal.
00:03:46.410 --> 00:03:48.212
And so what I do is I then move,
00:03:48.212 --> 00:03:50.020
I then make sure that there's four digits
00:03:50.020 --> 00:03:52.030
to the right of the
decimal in the product.
00:03:52.030 --> 00:03:53.500
And so I would say, okay,
00:03:53.500 --> 00:03:55.970
one, two, three, four, that looks good
00:03:55.970 --> 00:03:57.660
and I've gotten the same answer
00:03:57.660 --> 00:03:59.380
a lot faster than we just did it.
00:03:59.380 --> 00:04:01.810
Well, whole reason why I
just did it the way I did
00:04:01.810 --> 00:04:04.240
is to show you why that works.
00:04:04.240 --> 00:04:07.160
When we take the product
of the two numbers
00:04:07.160 --> 00:04:08.590
without the decimals,
00:04:08.590 --> 00:04:10.170
we're essentially ignoring the fact
00:04:10.170 --> 00:04:12.530
that the original product
was dividing by 10
00:04:12.530 --> 00:04:14.290
and dividing by 1,000,
00:04:14.290 --> 00:04:16.390
and that's because we had one digit
00:04:16.390 --> 00:04:17.960
behind to the right of the decimal here,
00:04:17.960 --> 00:04:20.350
and we had three digits to the
right of the decimal there.
00:04:20.350 --> 00:04:23.000
And so later after we take the product,
00:04:23.000 --> 00:04:25.700
we have to go and then
actually take that product
00:04:25.700 --> 00:04:27.260
and divide by 10,
00:04:27.260 --> 00:04:28.490
and divide by 1,000
00:04:28.490 --> 00:04:30.290
or divide by 10,000.
00:04:30.290 --> 00:04:32.900
So that's why you can then
just say, all right, well now,
00:04:32.900 --> 00:04:34.630
we originally had four
digits to the right,
00:04:34.630 --> 00:04:36.460
so we still have to have four digits
00:04:36.460 --> 00:04:38.160
to the right of the decimal point.
|
Noble’s Story | https://www.youtube.com/watch?v=Zbir-vpwX7Q | vtt | https://www.youtube.com/api/timedtext?v=Zbir-vpwX7Q&ei=xFWUZfCvEbasp-oP_eehwA8&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245300&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=242192E7E9EFD79F26C0A0D1914E326B2D73A916.352D923DA6CA4DF0293B9D26B37FDB77384DE97A&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.000 --> 00:00:01.810
- That was one of the
best days of my life.
00:00:01.810 --> 00:00:03.180
Honestly, like signing day,
00:00:03.180 --> 00:00:05.270
just knew that all the
hard work that I had put
00:00:05.270 --> 00:00:07.280
into this dream final paid off.
00:00:07.280 --> 00:00:09.940
I'm Noble. I'm a freshman
at Brown University.
00:00:09.940 --> 00:00:11.420
I play receiver on the football team.
00:00:11.420 --> 00:00:14.280
It became apparent to me that
when I got to high school
00:00:14.280 --> 00:00:16.220
that if I wanted to achieve the goals
00:00:16.220 --> 00:00:18.012
of going Division One football
00:00:18.012 --> 00:00:19.800
and going to school in the Ivy League,
00:00:19.800 --> 00:00:22.180
that I needed to improve on my SAT scores.
00:00:22.180 --> 00:00:25.170
A lot of people like my
peers have test anxiety.
00:00:25.170 --> 00:00:27.390
First time I took it, I got a 1210.
00:00:27.390 --> 00:00:29.510
I knew I needed to
improve if I wanted to get
00:00:29.510 --> 00:00:31.420
to a level of school that I'd envisioned.
00:00:31.420 --> 00:00:34.330
So, I dug into Khan Academy a lot.
00:00:34.330 --> 00:00:37.860
I took advantage of the option
to upload your SAT scores
00:00:37.860 --> 00:00:40.050
to Khan Academy, and it
would give you feedback
00:00:40.050 --> 00:00:41.540
on things you needed to work on.
00:00:41.540 --> 00:00:44.030
I definitely took a lot of
stress off of my shoulders
00:00:44.030 --> 00:00:45.140
and like having the confidence
00:00:45.140 --> 00:00:47.460
that I could truly go
into this test and perform
00:00:47.460 --> 00:00:49.900
to the standards that I
wanted. By using Khan Academy
00:00:49.900 --> 00:00:53.318
I was able to improve my
SAT score by 210 points.
00:00:53.318 --> 00:00:54.900
I was able to get a 1420,
00:00:54.900 --> 00:00:56.860
and that was a score that
got me accepted in the Brown.
00:00:56.860 --> 00:00:58.240
Definitely would say it's life changing.
00:00:58.240 --> 00:01:00.010
I set my life on trajectory
00:01:00.010 --> 00:01:01.360
that wouldn't have been available
00:01:01.360 --> 00:01:02.960
if I didn't have access to Khan Academy.
00:01:02.960 --> 00:01:04.700
Whether you're upper class or lower class,
00:01:04.700 --> 00:01:06.717
or anywhere you fall in between those,
00:01:06.717 --> 00:01:08.770
and it's free and available for everyone.
00:01:08.770 --> 00:01:11.120
And that's, I can't stress that enough.
00:01:11.120 --> 00:01:14.030
I wanna leave a message
that anything is possible.
00:01:14.030 --> 00:01:16.760
I definitely think the best
beginning spot would be
00:01:16.760 --> 00:01:17.810
through Khan Academy.
|
Dividing a whole number by a fraction with reciprocal | https://www.youtube.com/watch?v=G7c0CBLWVfs | vtt | https://www.youtube.com/api/timedtext?v=G7c0CBLWVfs&ei=xFWUZfaMKYK5mLAPtLWl2AI&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245300&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=53B28FAA08980FD4B5EEF65FE74A522E76FB4504.4550D1198DC9B5C5D54C7692A43CB37A32279A82&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.180 --> 00:00:02.010
- [Instructor] In this video,
we're gonna do an example
00:00:02.010 --> 00:00:03.480
that gives us a little bit of practice
00:00:03.480 --> 00:00:05.960
to think about what does it
mean to divide by a fraction?
00:00:05.960 --> 00:00:06.860
So if we wanna figure out
00:00:06.860 --> 00:00:09.500
what eight divided by 7/5 is,
00:00:09.500 --> 00:00:12.170
but we're gonna break
it down into two steps.
00:00:12.170 --> 00:00:14.410
First of all, we're gonna
use these visuals here
00:00:14.410 --> 00:00:19.000
to think about how many
groups of 7/5 are in one.
00:00:19.000 --> 00:00:20.110
Or another way of thinking about it
00:00:20.110 --> 00:00:24.100
is how these 7/5 are in a whole?
00:00:24.100 --> 00:00:27.000
So pause this video, and just
think about this first part.
00:00:28.100 --> 00:00:31.600
All right, so let's look at 7/5.
00:00:31.600 --> 00:00:36.600
7/5 is everything from
here, all the way to there.
00:00:37.360 --> 00:00:40.730
And then one is this.
00:00:40.730 --> 00:00:44.520
So how many 7/5 are in one?
00:00:44.520 --> 00:00:45.730
Well, you can see that one,
00:00:45.730 --> 00:00:50.120
which is the same thing
as 5/5, is less than 7/5.
00:00:50.120 --> 00:00:53.560
So it's actually going
to be a fraction of a 7/5
00:00:53.560 --> 00:00:57.090
that is one, or that is in one.
00:00:57.090 --> 00:00:59.500
And you can see what that fraction is.
00:00:59.500 --> 00:01:02.750
One is what fraction of 7/5.
00:01:02.750 --> 00:01:04.270
Well, if you look at the fifths,
00:01:04.270 --> 00:01:08.760
7/5 is of course seven of
them, and a whole is 5/5,
00:01:08.760 --> 00:01:13.760
so five of the 7/5 make a whole.
00:01:13.760 --> 00:01:17.980
So the answer right over here is 5/7.
00:01:17.980 --> 00:01:22.980
5/7 of a 7/5 is equal to one.
00:01:23.460 --> 00:01:25.400
You can also see this right over here.
00:01:25.400 --> 00:01:28.460
If you take each of these to be a fifth,
00:01:28.460 --> 00:01:31.720
each of these to be a fifth,
00:01:31.720 --> 00:01:36.720
then this whole bar is equal to 7/5.
00:01:36.760 --> 00:01:39.080
And the blue part is equal to one.
00:01:39.080 --> 00:01:41.630
So how many 7/5 are in the blue part?
00:01:41.630 --> 00:01:45.520
Well, we can see it's
5/7 of the whole bar.
00:01:45.520 --> 00:01:48.020
Once again, 5/7 of the whole bar.
00:01:48.020 --> 00:01:48.992
So we can also think about this
00:01:48.992 --> 00:01:53.350
as one divided by 7/5.
00:01:53.350 --> 00:01:57.190
This is another way of saying
how many 7/5 are in one,
00:01:57.190 --> 00:01:59.820
or how many groups of 7/5 are in one?
00:01:59.820 --> 00:02:02.890
And this is equal to 5/7,
00:02:02.890 --> 00:02:04.610
which we've learned in other videos
00:02:04.610 --> 00:02:06.590
is the reciprocal of 7/5.
00:02:06.590 --> 00:02:09.800
The numerator and the
denominator is swapped.
00:02:09.800 --> 00:02:14.150
So now what is eight
divided by 7/5 going to be?
00:02:14.150 --> 00:02:17.960
Well, if one divided by 7/5 is 5/7,
00:02:17.960 --> 00:02:21.540
or if you have 5/7 of a 7/5,
00:02:21.540 --> 00:02:22.950
of a 7/5 in one,
00:02:22.950 --> 00:02:25.260
I know the oral language
gets a little bit confusing.
00:02:25.260 --> 00:02:28.350
Well, you're going to have
eight times that many in eight.
00:02:28.350 --> 00:02:29.860
So this is going to be the same thing
00:02:29.860 --> 00:02:34.510
as eight times, we could do it this way,
00:02:34.510 --> 00:02:39.030
eight times one, divided by 7/5.
00:02:39.030 --> 00:02:41.960
Or you could just view this as eight times
00:02:41.960 --> 00:02:46.910
the reciprocal of 7/5,
which is five over seven.
00:02:48.150 --> 00:02:50.900
And we've learned how
to multiply this before.
00:02:50.900 --> 00:02:54.130
Eight times 5/7 is going to be equal
00:02:54.130 --> 00:02:58.170
to 40/7, and we're done.
00:02:58.170 --> 00:03:00.280
You could obviously also
write that as a mixed number
00:03:00.280 --> 00:03:05.253
if you like, this would be
the same thing as 5 5/7.
00:03:06.890 --> 00:03:10.000
So the big picture is when we think about
00:03:10.000 --> 00:03:13.030
how many of a fraction are in one,
00:03:13.030 --> 00:03:14.140
that's the same thing as saying,
00:03:14.140 --> 00:03:16.240
what's one divided by that fraction?
00:03:16.240 --> 00:03:17.980
As you see visually here,
00:03:17.980 --> 00:03:20.330
you essentially get the
reciprocal of that fraction.
00:03:20.330 --> 00:03:22.970
And so if you take any
other number other than one
00:03:22.970 --> 00:03:24.350
divided by that fraction,
00:03:24.350 --> 00:03:25.652
you're essentially just gonna multiply it
00:03:25.652 --> 00:03:30.000
by that reciprocal, because
it's that number times one.
00:03:30.000 --> 00:03:32.120
So when you divide by that fraction,
00:03:32.120 --> 00:03:34.683
it's that number times the reciprocal.
|
Area of quadrilateral with 2 parallel sides | https://www.youtube.com/watch?v=uEIoh8uWs1U | vtt | https://www.youtube.com/api/timedtext?v=uEIoh8uWs1U&ei=xFWUZZ-DELqpp-oP4eSDsAE&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245300&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=5364DD41DE8CAC66F09C87193D4E6F3B47237D5B.69AAE8E8FE3588652055A4388BDE99416CFE82F0&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.350 --> 00:00:02.140
- [Instructor] What we're going
to try to do in this video
00:00:02.140 --> 00:00:04.430
is find the area of this figure.
00:00:04.430 --> 00:00:05.930
And we can see it's a quadrilateral.
00:00:05.930 --> 00:00:08.740
It has 1, 2, 3, 4 sides.
00:00:08.740 --> 00:00:11.180
And we know that this side and this side
00:00:11.180 --> 00:00:13.570
that they're parallel to each other.
00:00:13.570 --> 00:00:16.160
You can see that they
both form right angles
00:00:16.160 --> 00:00:18.080
with this dotted line.
00:00:18.080 --> 00:00:21.063
So pause this video and see
if you can find the area.
00:00:22.930 --> 00:00:23.763
All right.
00:00:23.763 --> 00:00:25.590
Now, if you had a little
bit of trouble with that
00:00:25.590 --> 00:00:27.160
I'll give you a hint.
00:00:27.160 --> 00:00:29.350
What if we were to take this quadrilateral
00:00:29.350 --> 00:00:32.220
and divide it into two triangles?
00:00:32.220 --> 00:00:35.470
So let me do this in a color
that you are likely to see.
00:00:35.470 --> 00:00:39.120
So if I were to draw a line like this
00:00:39.120 --> 00:00:43.670
it now divides the quadrilateral
into two triangles.
00:00:43.670 --> 00:00:47.630
If I were to take this
triangle right over here
00:00:47.630 --> 00:00:50.660
I could take it out and reorient it,
00:00:50.660 --> 00:00:54.990
so it looks something like this,
00:00:54.990 --> 00:00:59.290
where the base has length 8,
00:00:59.290 --> 00:01:03.220
and then the height right
over here, the height
00:01:03.220 --> 00:01:06.070
this has length 5.
00:01:06.070 --> 00:01:07.720
So that would be that triangle.
00:01:07.720 --> 00:01:10.890
And then, this triangle over here
00:01:10.890 --> 00:01:13.230
if you were to take it out
and reorient it a little bit
00:01:13.230 --> 00:01:14.440
it could look like this,
00:01:14.440 --> 00:01:16.220
where the base is 4,
00:01:16.220 --> 00:01:19.990
and the triangle looks something like,
00:01:19.990 --> 00:01:21.270
looks something like this.
00:01:21.270 --> 00:01:24.290
So the base is 4,
00:01:24.290 --> 00:01:27.240
and then the height is going to be 5.
00:01:27.240 --> 00:01:30.680
So this height right
over here, this height,
00:01:30.680 --> 00:01:32.290
we notice this is a right angle.
00:01:32.290 --> 00:01:34.630
So from here to here,
which is the same thing
00:01:34.630 --> 00:01:37.560
as from here to right over here,
00:01:37.560 --> 00:01:39.080
we know that this is 5.
00:01:39.080 --> 00:01:41.470
So that's my fairly big hint to you,
00:01:41.470 --> 00:01:44.540
if you know how to find
the area of a triangle.
00:01:44.540 --> 00:01:49.540
The area of a triangle we
know is 1/2 base times height.
00:01:50.140 --> 00:01:51.700
So the area of this one right over here
00:01:51.700 --> 00:01:56.700
is gonna be 1/2 times 8 times 5.
00:01:57.040 --> 00:01:58.840
And the area of this one over here
00:01:58.840 --> 00:02:02.480
is going to be 1/2 times the base,
00:02:02.480 --> 00:02:07.470
which is 4 times the height, which is 5.
00:02:07.470 --> 00:02:09.480
And we could evaluate each of these,
00:02:09.480 --> 00:02:10.840
or we could just add them together.
00:02:10.840 --> 00:02:12.580
That the area of the entire thing
00:02:12.580 --> 00:02:16.960
is going to be 1/2 times
this base right over here
00:02:16.960 --> 00:02:21.690
which is 8, times the height, which is 5,
00:02:21.690 --> 00:02:26.690
plus 1/2 times this side,
00:02:27.500 --> 00:02:30.640
you could do that as
the other base, times 4
00:02:30.640 --> 00:02:33.400
times that same height, times 5.
00:02:33.400 --> 00:02:35.260
And obviously, you
could just evaluate this
00:02:35.260 --> 00:02:38.330
or we could see some
interesting things about it.
00:02:38.330 --> 00:02:40.440
We could express this as well
00:02:40.440 --> 00:02:45.440
if we were to factor
out 1/2 and the 5 here.
00:02:45.520 --> 00:02:48.403
This could be rewritten as 1/2,
00:02:49.740 --> 00:02:54.250
1/2 times 8 plus 4,
00:02:54.250 --> 00:02:58.110
8 plus 4.
00:02:58.110 --> 00:03:03.110
And then, all of that, all of
that times 5 right over here.
00:03:03.830 --> 00:03:05.770
And so, another way you
could think about it is
00:03:05.770 --> 00:03:08.670
the average of the length
of these two bases.
00:03:08.670 --> 00:03:11.220
You could view this as base 1 and base 2,
00:03:11.220 --> 00:03:12.730
you multiply that times the height
00:03:12.730 --> 00:03:15.710
and you have the area
of this quadrilateral.
00:03:15.710 --> 00:03:16.970
Well, what's that going to be?
00:03:16.970 --> 00:03:19.344
8 plus 4 is 12.
00:03:19.344 --> 00:03:22.810
1/2 times 12, this is all going to be 6.
00:03:22.810 --> 00:03:27.560
6 times 5 is going to be
equal to 30 square units.
00:03:27.560 --> 00:03:28.393
You could have figured it out here too.
00:03:28.393 --> 00:03:32.570
1/2 times 8 is 4, times 5 is 20.
00:03:32.570 --> 00:03:35.230
And then, this would've
been 1/2 times 4 is 2,
00:03:35.230 --> 00:03:36.470
times 5 is 10.
00:03:36.470 --> 00:03:40.323
20 plus 10 is 30 square units once again.
|
Competition, predation, and mutualism | https://www.youtube.com/watch?v=S65RR_pEyPw | vtt | https://www.youtube.com/api/timedtext?v=S65RR_pEyPw&ei=xFWUZaOLJNGMvdIPm_yq4Ao&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245300&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=43D11FE9C44BFF57A9233615EAB3A234DF6C4938.6ECE2AF125E0B0370E4FF660AAA564BDB4221689&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.770 --> 00:00:02.430
- [Instructor] All across ecosystems,
00:00:02.430 --> 00:00:05.940
we know that organisms
interact in specific ways
00:00:05.940 --> 00:00:07.880
and scientists use special words
00:00:07.880 --> 00:00:11.000
to describe these types of interaction,
00:00:11.000 --> 00:00:14.990
competition, predation and mutualism.
00:00:14.990 --> 00:00:16.900
So let's first talk about competition
00:00:16.900 --> 00:00:19.590
which we have already talked
about in other videos.
00:00:19.590 --> 00:00:22.210
In this picture here,
do you see competition?
00:00:22.210 --> 00:00:24.110
Pause this video and think about that.
00:00:25.350 --> 00:00:27.710
Well, one limited resource
00:00:27.710 --> 00:00:30.830
that these animals need
to survive is water.
00:00:30.830 --> 00:00:33.090
There's only a limited
amount in this watering hole
00:00:33.090 --> 00:00:36.140
over here and so you could
imagine there is competition
00:00:36.140 --> 00:00:38.650
not just amongst the
members of a population
00:00:38.650 --> 00:00:40.520
let's say between the zebra
00:00:40.520 --> 00:00:43.090
but also between members
of different species,
00:00:43.090 --> 00:00:45.630
between different
populations in a community.
00:00:45.630 --> 00:00:48.580
The zebras are not just competing
for water with each other
00:00:48.580 --> 00:00:50.160
but also with these antelope
00:00:50.160 --> 00:00:52.880
or with these buffalo over here.
00:00:52.880 --> 00:00:54.840
There might also be competition for food.
00:00:54.840 --> 00:00:57.140
It doesn't seem like there's
a lot of grass to eat
00:00:57.140 --> 00:01:00.460
for all of these animals
that like to graze on grass.
00:01:00.460 --> 00:01:03.220
So now let's move on to predation.
00:01:03.220 --> 00:01:07.200
Predation is when one
organism eats another organism
00:01:07.200 --> 00:01:09.320
usually to its own benefit.
00:01:09.320 --> 00:01:11.930
Do you see any predation happening here?
00:01:11.930 --> 00:01:13.370
Well, we don't see any of these animals
00:01:13.370 --> 00:01:14.670
chasing and killing each other.
00:01:14.670 --> 00:01:17.250
There might be other
animals like lions offscreen
00:01:17.250 --> 00:01:20.280
that might hunt and kill
and eat these animals
00:01:20.280 --> 00:01:21.350
right over here
00:01:21.350 --> 00:01:23.670
but we know that these
animals do eat grass
00:01:23.670 --> 00:01:26.470
and as I said, it's not just about hunting
00:01:26.470 --> 00:01:29.640
and killing and eating
from one animal to another.
00:01:29.640 --> 00:01:31.480
It could be one organism to another.
00:01:31.480 --> 00:01:33.550
So the eating of the
grass by these animals
00:01:33.550 --> 00:01:36.570
could actually be considered
a form of predation
00:01:36.570 --> 00:01:38.980
especially if it kills the grass.
00:01:38.980 --> 00:01:42.190
A more obvious form of predation
is this brown bear here
00:01:42.190 --> 00:01:45.540
that has gotten the
salmon out of this river.
00:01:45.540 --> 00:01:49.340
It is clearly hunting and killing
the salmon for its benefit
00:01:49.340 --> 00:01:51.090
and it is likely that each of these bears
00:01:51.090 --> 00:01:52.940
are in competition with other bears
00:01:52.940 --> 00:01:55.360
for this limited resource.
00:01:55.360 --> 00:01:56.710
So last but not least,
00:01:56.710 --> 00:01:59.590
let's think a little bit about mutualism.
00:01:59.590 --> 00:02:02.610
Mutualism happens when
two organisms benefit
00:02:02.610 --> 00:02:04.363
from interacting with each other.
00:02:05.200 --> 00:02:07.620
Right over here, we have these starlings
00:02:07.620 --> 00:02:10.020
that actually hang out on this buffalo
00:02:10.020 --> 00:02:13.830
and pick lice and ticks
off the buffalo's fur.
00:02:13.830 --> 00:02:16.337
This is mutualism because
both parties benefit.
00:02:16.337 --> 00:02:18.310
The starlings are able to get food
00:02:18.310 --> 00:02:20.760
and the buffalo no longer
have these parasites,
00:02:20.760 --> 00:02:23.280
these things that are
living off of the buffalo
00:02:23.280 --> 00:02:25.520
sucking its blood out of its body
00:02:25.520 --> 00:02:28.280
and also probably not itching as much.
00:02:28.280 --> 00:02:30.120
Now, based on how I just described it,
00:02:30.120 --> 00:02:32.260
there's not just mutualism here.
00:02:32.260 --> 00:02:33.760
There's also predation
00:02:33.760 --> 00:02:35.980
because these birds are actually hunting
00:02:35.980 --> 00:02:39.750
and killing the lice and the
ticks on the buffalo's body.
00:02:39.750 --> 00:02:41.880
Now, related to being a
predator is another word
00:02:41.880 --> 00:02:43.190
known as being a parasite
00:02:43.190 --> 00:02:45.050
and that's what the lice
and the ticks are doing
00:02:45.050 --> 00:02:47.150
where they're sucking
the blood of the buffalo
00:02:47.150 --> 00:02:48.780
but they're not considered predators.
00:02:48.780 --> 00:02:51.860
They're more parasites because
they don't kill the buffalo.
00:02:51.860 --> 00:02:54.530
They're just taking some
resources away from it.
00:02:54.530 --> 00:02:55.560
So I'll leave you there.
00:02:55.560 --> 00:02:57.130
I encourage you when you look at nature,
00:02:57.130 --> 00:02:58.490
when you go to a park next time,
00:02:58.490 --> 00:03:00.570
when you go watch a documentary,
00:03:00.570 --> 00:03:02.960
I encourage you to think
about how competition,
00:03:02.960 --> 00:03:06.730
predation and mutualism is
happening in an ecosystem
00:03:06.730 --> 00:03:08.980
that you are seeing or
that you're a part of.
|
Resources and population growth | https://www.youtube.com/watch?v=i5uF5inpY7s | vtt | https://www.youtube.com/api/timedtext?v=i5uF5inpY7s&ei=xFWUZZiMFK2WhcIPuP-lqAc&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245300&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=DDAD362B88CAB6AA065570DFC6DB7ED8FADF7E67.93A5AB520C6B9FB983FB86534482C325D225491B&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.350 --> 00:00:02.280
- [Instructor] So we have a
picture here of these animals
00:00:02.280 --> 00:00:03.570
at a watering hole.
00:00:03.570 --> 00:00:07.940
And my question to you is why
don't we see more animals?
00:00:07.940 --> 00:00:10.640
There's clearly enough
space for more animals,
00:00:10.640 --> 00:00:12.470
and we also know that if we focus
00:00:12.470 --> 00:00:15.510
on any one of these
populations, say zebra,
00:00:15.510 --> 00:00:19.960
that every one zebra can have
far more than one offspring
00:00:19.960 --> 00:00:21.020
in their lifetime.
00:00:21.020 --> 00:00:22.540
And that not only that,
00:00:22.540 --> 00:00:24.167
but those offspring can
then have offspring,
00:00:24.167 --> 00:00:25.350
and so on and so forth.
00:00:25.350 --> 00:00:27.050
So it seems like over time,
00:00:27.050 --> 00:00:29.470
these zebra should just be
able to keep multiplying
00:00:29.470 --> 00:00:31.150
until they fill up all of this land,
00:00:31.150 --> 00:00:32.630
similar for the buffalo,
00:00:32.630 --> 00:00:34.310
similar for the antelope.
00:00:34.310 --> 00:00:36.030
Why don't we see that?
00:00:36.030 --> 00:00:38.730
Pause this video and think about that.
00:00:38.730 --> 00:00:42.350
So let's start by thinking
about what any organism,
00:00:42.350 --> 00:00:44.370
or a population of organisms,
00:00:44.370 --> 00:00:47.890
or a community of
populations need to survive.
00:00:47.890 --> 00:00:50.590
Most animals that live on the
surface, like these animals,
00:00:50.590 --> 00:00:52.700
need air, especially oxygen.
00:00:52.700 --> 00:00:54.980
Plants need carbon dioxide from the air.
00:00:54.980 --> 00:00:57.840
They need water.
00:00:57.840 --> 00:01:01.810
They need a source of energy,
which I will call food,
00:01:01.810 --> 00:01:03.840
or I could say it's energy here,
00:01:03.840 --> 00:01:05.610
because it's not always
in the form of food
00:01:05.610 --> 00:01:07.310
as we might recognize it.
00:01:07.310 --> 00:01:09.570
And I guess if we think really basically,
00:01:09.570 --> 00:01:12.400
they need space in which to exist.
00:01:12.400 --> 00:01:13.690
Now, as I mentioned,
00:01:13.690 --> 00:01:16.700
there seems to be a lot of
space here for the animals,
00:01:16.700 --> 00:01:19.080
so that doesn't seem to be the resource
00:01:19.080 --> 00:01:21.880
that is limiting their growth.
00:01:21.880 --> 00:01:24.010
So let's rule that out here.
00:01:24.010 --> 00:01:25.540
Now, it's also clear that
it seems like there's
00:01:25.540 --> 00:01:27.410
a fairly large amount of air here,
00:01:27.410 --> 00:01:30.320
more than enough air for
these populations to grow,
00:01:30.320 --> 00:01:32.590
so that doesn't seem to be a resource
00:01:32.590 --> 00:01:34.970
that's somehow putting
a maximum on how many
00:01:34.970 --> 00:01:36.610
of these organisms there are.
00:01:36.610 --> 00:01:39.450
It does not look like a limited resource,
00:01:39.450 --> 00:01:42.060
or a limiting resource.
00:01:42.060 --> 00:01:43.860
Now, what about water?
00:01:43.860 --> 00:01:45.820
Well, water does seem interesting here,
00:01:45.820 --> 00:01:47.980
because this watering hole does not seem
00:01:47.980 --> 00:01:48.970
like it's very deep.
00:01:48.970 --> 00:01:51.630
It does not seem like
there's a lot of water here.
00:01:51.630 --> 00:01:55.350
So this one could be what we
would call a limited resource
00:01:55.350 --> 00:01:57.180
that is limiting population.
00:01:57.180 --> 00:01:58.970
Maybe if they had more and more offspring,
00:01:58.970 --> 00:02:00.810
there just wouldn't be enough water
00:02:00.810 --> 00:02:02.800
for any member of a population,
00:02:02.800 --> 00:02:04.880
and then of course the
populations would be competing
00:02:04.880 --> 00:02:05.790
with each other as well,
00:02:05.790 --> 00:02:09.170
because they all need
the same water to drink.
00:02:09.170 --> 00:02:10.900
Now, what about food?
00:02:10.900 --> 00:02:13.110
Well, you might recognize that zebra,
00:02:13.110 --> 00:02:15.320
or antelope, or buffalo,
00:02:15.320 --> 00:02:17.070
they tend to graze on grasses,
00:02:17.070 --> 00:02:19.450
and there are some grasses over here,
00:02:19.450 --> 00:02:21.700
but we also see that a
lot of the grass is dead
00:02:21.700 --> 00:02:22.780
or dried out,
00:02:22.780 --> 00:02:25.480
and there's just a lot
of areas with dirt here.
00:02:25.480 --> 00:02:27.710
So it looks like the food and energy
00:02:27.710 --> 00:02:30.739
is also a limiting resource.
00:02:30.739 --> 00:02:32.470
And we have to remind
ourselves there's populations
00:02:32.470 --> 00:02:33.720
of different types of grasses,
00:02:33.720 --> 00:02:35.550
and why aren't they spreading more?
00:02:35.550 --> 00:02:37.030
Well, from the perspective of a plant,
00:02:37.030 --> 00:02:39.630
it looks like the air and
space is for sure abundant,
00:02:39.630 --> 00:02:42.130
and even energy in the form of sunlight
00:02:42.130 --> 00:02:44.120
is abundant based on this picture,
00:02:44.120 --> 00:02:46.840
so it's probably water
is the limited resource,
00:02:46.840 --> 00:02:48.640
which is keeping us
from having more plants
00:02:48.640 --> 00:02:50.790
and grasses in this picture.
00:02:50.790 --> 00:02:53.740
We can imagine a scenario
in which it rains a lot.
00:02:53.740 --> 00:02:56.510
There's a lot of water, water is abundant,
00:02:56.510 --> 00:02:59.680
then all of the different
types of populations of grasses
00:02:59.680 --> 00:03:01.050
are able to expand,
00:03:01.050 --> 00:03:03.650
and then there's more
than enough food and water
00:03:03.650 --> 00:03:06.470
for these animals to keep reproducing.
00:03:06.470 --> 00:03:09.370
In that case, space might become an issue.
00:03:09.370 --> 00:03:11.070
But the important thing to realize here
00:03:11.070 --> 00:03:15.410
is that all organisms need
resources in order to survive
00:03:15.410 --> 00:03:18.160
and in order to multiply and reproduce.
00:03:18.160 --> 00:03:20.670
Populations of many different
species are often competing
00:03:20.670 --> 00:03:21.670
for those resources.
00:03:21.670 --> 00:03:22.950
Like the water here,
00:03:22.950 --> 00:03:24.490
that will tend to put a limit
00:03:24.490 --> 00:03:27.040
on how much these populations can grow.
00:03:27.040 --> 00:03:29.770
And the limit on one
population can affect another.
00:03:29.770 --> 00:03:31.620
As we said, if you had more water,
00:03:31.620 --> 00:03:32.830
you could have more grass,
00:03:32.830 --> 00:03:35.000
which will allow them
for more food and energy
00:03:35.000 --> 00:03:37.083
for these other populations.
|
Populations, communities, and ecosystems | https://www.youtube.com/watch?v=xzINev2Bd8s | vtt | https://www.youtube.com/api/timedtext?v=xzINev2Bd8s&ei=xFWUZaPDFLiBhcIPxNOJ-AY&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245300&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=870B67ACE284D46E5F717326F51E858DC09EC737.70EBA0E4C538A171BD990C2F7EE6F70E3523120F&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.170 --> 00:00:01.700
- [Instructor] In biology, it's useful
00:00:01.700 --> 00:00:03.350
to have some shared language
00:00:03.350 --> 00:00:06.500
so we can communicate and
describe the world around us
00:00:06.500 --> 00:00:09.580
in ways that we can all
understand together.
00:00:09.580 --> 00:00:11.650
So here, we're going to
talk about populations,
00:00:11.650 --> 00:00:13.570
communities, and ecosystems.
00:00:13.570 --> 00:00:17.060
And as we will see, these
are all related ideas.
00:00:17.060 --> 00:00:21.420
So first of all, a population
is talking about the members
00:00:21.420 --> 00:00:24.110
of a specific species in an area.
00:00:24.110 --> 00:00:26.710
So for example, in this picture,
00:00:26.710 --> 00:00:29.540
we have a population of zebra.
00:00:29.540 --> 00:00:32.970
I have one zebra there, one zebra there,
00:00:32.970 --> 00:00:35.090
there might be some
others that we can't see.
00:00:35.090 --> 00:00:36.580
In fact, there are likely to be.
00:00:36.580 --> 00:00:40.560
So, these are each members
of a population of zebra.
00:00:40.560 --> 00:00:43.060
Now, we have other
populations in this picture.
00:00:43.060 --> 00:00:45.380
We have a population of buffalo.
00:00:45.380 --> 00:00:48.240
These three are members
of that population.
00:00:48.240 --> 00:00:50.580
We have a population of antelope.
00:00:50.580 --> 00:00:53.420
In fact, there is a bunch
of antelope in this picture.
00:00:53.420 --> 00:00:55.630
So, we have many members
of that population.
00:00:55.630 --> 00:00:58.080
We even see some animals
here in the background.
00:00:58.080 --> 00:01:00.500
I can't quite make out what they are,
00:01:00.500 --> 00:01:02.560
but that could be a different population.
00:01:02.560 --> 00:01:04.010
Let's say if those are elephants,
00:01:04.010 --> 00:01:06.230
they might be elephants
the way I see them,
00:01:06.230 --> 00:01:09.030
but that could be members of
a population of elephants.
00:01:09.030 --> 00:01:13.350
So if that is a population,
what is a community?
00:01:13.350 --> 00:01:16.840
Well, a community is all
of the living species
00:01:16.840 --> 00:01:19.030
that live in the same area.
00:01:19.030 --> 00:01:21.060
So, we have a community of animals
00:01:21.060 --> 00:01:24.770
that is made up of populations of buffalo,
00:01:24.770 --> 00:01:27.770
of zebra, and of antelope.
00:01:27.770 --> 00:01:30.560
And I wanna make clear
that the populations
00:01:30.560 --> 00:01:31.930
or when we're talking
about the communities,
00:01:31.930 --> 00:01:33.550
we're not necessarily just talking
00:01:33.550 --> 00:01:36.050
about large animals like this.
00:01:36.050 --> 00:01:38.940
We could be talking about
populations of mosquitoes.
00:01:38.940 --> 00:01:41.470
We could be talking about
populations of fish in this pond,
00:01:41.470 --> 00:01:42.740
if there are any fish.
00:01:42.740 --> 00:01:45.400
We could have a population of
a certain species of plant.
00:01:45.400 --> 00:01:47.380
And likewise, when we're
talking about communities,
00:01:47.380 --> 00:01:48.330
we're talking about collectively
00:01:48.330 --> 00:01:50.890
all of the living organisms together.
00:01:50.890 --> 00:01:54.560
Now, last but not least, what
would be an ecosystem then?
00:01:54.560 --> 00:01:57.540
Well, an ecosystem is all
of the living organisms
00:01:57.540 --> 00:01:59.870
plus all of the non-living things.
00:01:59.870 --> 00:02:01.920
So, the ecosystem that we see here
00:02:01.920 --> 00:02:03.700
would also include the water,
00:02:03.700 --> 00:02:05.370
it would also include the dirt,
00:02:05.370 --> 00:02:07.370
it would also include the air.
00:02:07.370 --> 00:02:09.930
And organisms like those
that we see right here
00:02:09.930 --> 00:02:12.430
are constantly interacting
with both the living
00:02:12.430 --> 00:02:15.040
and nonliving parts of their environment.
00:02:15.040 --> 00:02:17.560
These interactions are
how organisms get food,
00:02:17.560 --> 00:02:20.070
shelter, water, and warmth.
00:02:20.070 --> 00:02:22.880
These interactions are
how organisms survive
00:02:22.880 --> 00:02:24.420
and produce offspring.
00:02:24.420 --> 00:02:26.070
So, let's get a little bit more practice
00:02:26.070 --> 00:02:30.110
with this idea of populations,
communities, and ecosystems.
00:02:30.110 --> 00:02:32.760
And we will do that by
looking at this picture
00:02:32.760 --> 00:02:34.050
right over here.
00:02:34.050 --> 00:02:36.060
Pause this video and think about
00:02:36.060 --> 00:02:38.073
what are the populations here?
00:02:40.260 --> 00:02:41.700
Well, you might not know the name
00:02:41.700 --> 00:02:43.160
of all these different types of fish,
00:02:43.160 --> 00:02:44.790
but you can see that there's a population
00:02:44.790 --> 00:02:47.870
of this gold-colored fish right over here.
00:02:47.870 --> 00:02:51.910
There's also another population
of this blue-colored fish.
00:02:51.910 --> 00:02:54.130
We could keep looking
for other populations.
00:02:54.130 --> 00:02:58.120
It looks like there's a
population of this silver-colored
00:02:58.120 --> 00:03:01.100
or I guess long-ish silver
fish right over here.
00:03:01.100 --> 00:03:02.740
But once again, it's not just the fish.
00:03:02.740 --> 00:03:04.180
There's a population of coral,
00:03:04.180 --> 00:03:06.140
there's populations of microorganisms
00:03:06.140 --> 00:03:08.210
that we can't see here.
00:03:08.210 --> 00:03:12.050
The community would be all
of these living organisms
00:03:12.050 --> 00:03:13.400
that live close to each other.
00:03:13.400 --> 00:03:15.730
And we'll see, sometimes
they compete with each other,
00:03:15.730 --> 00:03:17.460
sometimes they eat each other,
00:03:17.460 --> 00:03:18.810
but sometimes they help each other,
00:03:18.810 --> 00:03:20.930
Or sometimes they don't matter
that much to each other.
00:03:20.930 --> 00:03:23.640
And we'll study that in a lot more detail.
00:03:23.640 --> 00:03:26.950
And then the ecosystem
includes all of the above
00:03:26.950 --> 00:03:31.950
plus the water, plus the
oxygen that is in the water,
00:03:32.080 --> 00:03:35.650
plus the sand at the bottom of the ocean.
00:03:35.650 --> 00:03:37.000
So, I'll leave you there.
00:03:37.000 --> 00:03:38.750
Hopefully, you now have a sense
00:03:38.750 --> 00:03:40.400
of what biologists are talking about
00:03:40.400 --> 00:03:42.260
when they talk about populations,
00:03:42.260 --> 00:03:44.513
communities, and ecosystems.
|
Photosynthesis in organisms | https://www.youtube.com/watch?v=_BLShUdXbN4 | vtt | https://www.youtube.com/api/timedtext?v=_BLShUdXbN4&ei=xFWUZaCcEv7XxN8PyKCVsAk&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245300&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=963C846FE5DD8263429E1B4C2396D5A58CD0E769.314B86B0F6B8731FCD2A1FF8AD46A1C0154E2930&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.120 --> 00:00:01.440
- [Narrator] Hey, I'm gonna let you in
00:00:01.440 --> 00:00:03.040
on a little secret of mine.
00:00:03.040 --> 00:00:05.200
I love gardening.
00:00:05.200 --> 00:00:07.730
In fact, I have a huge garden with apples,
00:00:07.730 --> 00:00:10.000
blueberries, pumpkins, and tomatoes.
00:00:10.000 --> 00:00:13.630
I give my plants micronutrients,
and maybe some fertilizer.
00:00:13.630 --> 00:00:15.430
But I don't give them food in the same way
00:00:15.430 --> 00:00:19.180
that I would give my dog who
eats multiple times a day.
00:00:19.180 --> 00:00:21.490
With plants, I just put them in the soil,
00:00:21.490 --> 00:00:24.240
water them regularly, and watch them grow.
00:00:24.240 --> 00:00:25.470
How do they do it?
00:00:25.470 --> 00:00:28.140
Well, they use a process
called photosynthesis.
00:00:28.140 --> 00:00:30.790
Photosynthesis is a
scientific term to describe
00:00:30.790 --> 00:00:33.330
how certain living things
use energy from sunlight
00:00:33.330 --> 00:00:34.890
to live and grow.
00:00:34.890 --> 00:00:37.180
Many different kinds of plants, algae,
00:00:37.180 --> 00:00:40.010
and various single-celled
organisms are able to carry out
00:00:40.010 --> 00:00:41.820
this amazing process.
00:00:41.820 --> 00:00:45.090
Today, let's describe
photosynthesis using tomatoes.
00:00:45.090 --> 00:00:46.960
So here you see a young tomato plant,
00:00:46.960 --> 00:00:48.970
similar to the ones I
have in my own garden.
00:00:48.970 --> 00:00:51.290
Let's name it Planty.
00:00:51.290 --> 00:00:52.300
First, let's start off
00:00:52.300 --> 00:00:54.780
by looking at Planty's
immediate surroundings.
00:00:54.780 --> 00:00:57.270
The soil Planty is
growing in contains water
00:00:57.270 --> 00:01:00.120
and the air surrounding
Planty contains molecules
00:01:00.120 --> 00:01:01.590
of carbon dioxide.
00:01:01.590 --> 00:01:04.760
These two compounds are the
starting materials or inputs
00:01:04.760 --> 00:01:08.100
that Planty needs in order
to carry out photosynthesis.
00:01:08.100 --> 00:01:10.330
Now, let's take a look
at the weather forecast.
00:01:10.330 --> 00:01:12.650
Well, it looks like it's
gonna be a sunny day today.
00:01:12.650 --> 00:01:14.260
So when the sun shines on the earth,
00:01:14.260 --> 00:01:16.620
it sends out energy in the form of light.
00:01:16.620 --> 00:01:18.620
This energy is essential for Planty
00:01:18.620 --> 00:01:20.900
to be able to carry out photosynthesis.
00:01:20.900 --> 00:01:23.020
Next, let's take a closer look at Planty,
00:01:23.020 --> 00:01:26.060
because Planty's cells are
hiding a secret of their own.
00:01:26.060 --> 00:01:28.810
Inside Planty's cells are
microscopic structures
00:01:28.810 --> 00:01:31.180
that help Planty carry out photosynthesis.
00:01:31.180 --> 00:01:33.690
These structures are called chloroplasts.
00:01:33.690 --> 00:01:36.330
Chloroplasts contain
green pigment molecules
00:01:36.330 --> 00:01:37.600
called chlorophyll.
00:01:37.600 --> 00:01:39.580
It is actually within these molecules
00:01:39.580 --> 00:01:41.880
that the sun's energy is captured for use
00:01:41.880 --> 00:01:43.310
during photosynthesis.
00:01:43.310 --> 00:01:45.560
Interestingly, chlorophyll
is where leaves get
00:01:45.560 --> 00:01:46.730
their green color.
00:01:46.730 --> 00:01:49.270
To help you remember, think
of chlorophyll like this:
00:01:49.270 --> 00:01:52.550
chloro means green and phyll means leaf.
00:01:52.550 --> 00:01:55.600
So when you put them
together, you get green leaf.
00:01:55.600 --> 00:01:58.760
Okay, so now we know that
carbon dioxide, water,
00:01:58.760 --> 00:02:01.880
and sunlight are required
for photosynthesis to occur.
00:02:01.880 --> 00:02:04.310
And we know that in plants like Planty,
00:02:04.310 --> 00:02:06.740
photosynthesis happens in the chloroplast
00:02:06.740 --> 00:02:08.580
with the help of chlorophyll.
00:02:08.580 --> 00:02:10.580
Next, let's take a look at what happens
00:02:10.580 --> 00:02:13.370
during the process of
photosynthesis itself.
00:02:13.370 --> 00:02:15.670
When the sunlight reaches
Planty's chloroplast,
00:02:15.670 --> 00:02:18.190
its energy is used to rearrange the atoms
00:02:18.190 --> 00:02:20.810
in the carbon dioxide and water molecules
00:02:20.810 --> 00:02:23.080
through a series of chemical reactions.
00:02:23.080 --> 00:02:24.670
The outputs of these reactions
00:02:24.670 --> 00:02:27.310
are oxygen molecules and sugars.
00:02:27.310 --> 00:02:30.030
These sugars are vital
to Planty's survival
00:02:30.030 --> 00:02:32.690
because they are used as a
source of chemical energy
00:02:32.690 --> 00:02:34.800
that helps Planty live and grow.
00:02:34.800 --> 00:02:37.050
In other words, they're Planty's food.
00:02:37.050 --> 00:02:38.280
Planty can do a few things
00:02:38.280 --> 00:02:40.790
with the sugars made
during photosynthesis.
00:02:40.790 --> 00:02:42.000
It can break the sugars down
00:02:42.000 --> 00:02:44.200
to get usable energy right away,
00:02:44.200 --> 00:02:47.210
or it can store the sugar
molecules for later use.
00:02:47.210 --> 00:02:49.310
If Planty stores the sugar molecules,
00:02:49.310 --> 00:02:52.140
it can then use them as a
source of energy in the future.
00:02:52.140 --> 00:02:53.830
This means that Planty can grow
00:02:53.830 --> 00:02:55.900
even when the sun isn't shining.
00:02:55.900 --> 00:02:58.170
Planty can also use the sugar molecules
00:02:58.170 --> 00:03:00.750
to build larger molecules
such as cellulose
00:03:00.750 --> 00:03:03.230
that make up the structure
of Planty itself.
00:03:03.230 --> 00:03:06.240
In this way, Planty can
grow bigger and bigger
00:03:06.240 --> 00:03:08.350
with very little help from me;
00:03:08.350 --> 00:03:11.130
all thanks to the process
of photosynthesis.
00:03:11.130 --> 00:03:13.370
Planty's other output, oxygen,
00:03:13.370 --> 00:03:15.310
is released into the atmosphere.
00:03:15.310 --> 00:03:18.390
This is really cool because
it provides organisms
00:03:18.390 --> 00:03:22.060
in the ecosystem,
including us, with oxygen.
00:03:22.060 --> 00:03:25.330
So thanks Planty and other
photosynthetic organisms
00:03:25.330 --> 00:03:28.130
for giving us the oxygen
we need to breathe.
00:03:28.130 --> 00:03:31.000
And that, my friends, is photosynthesis.
00:03:31.000 --> 00:03:32.350
So next time you're in a garden,
00:03:32.350 --> 00:03:33.830
I want you to think about this.
00:03:33.830 --> 00:03:37.480
All the plant structures you
can see, such as stems, leaves,
00:03:37.480 --> 00:03:39.560
and even the fruits and
vegetables that we eat
00:03:39.560 --> 00:03:42.100
are made up mostly of the
atoms that were once a part
00:03:42.100 --> 00:03:44.740
of the starting materials
of photosynthesis.
00:03:44.740 --> 00:03:46.490
With the help of a little sunlight,
00:03:46.490 --> 00:03:49.410
the plants made their
own food and grew bigger,
00:03:49.410 --> 00:03:51.380
taking CO2 out of the atmosphere
00:03:51.380 --> 00:03:54.560
and releasing oxygen back
in for us to breathe.
00:03:54.560 --> 00:03:57.140
And on that note, I
think I should go outside
00:03:57.140 --> 00:03:59.200
and give my own garden some water.
00:03:59.200 --> 00:04:00.053
See you later.
|
Plant reproductive success | https://www.youtube.com/watch?v=nJIRCDipw7o | vtt | https://www.youtube.com/api/timedtext?v=nJIRCDipw7o&ei=xFWUZYXtL6COvdIPtJq8uAQ&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245300&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=7E6152BB728028158FA6B5DF58745C4EAD858166.18C8E428AC888A618E7123A02FD83D0CBA494659&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.380 --> 00:00:01.270
- [Instructor] We've already talked
00:00:01.270 --> 00:00:04.280
about reproductive
success in other videos.
00:00:04.280 --> 00:00:07.240
It's related to the number of offspring
00:00:07.240 --> 00:00:10.180
an organism can have in its lifetime.
00:00:10.180 --> 00:00:11.630
And so in this video,
00:00:11.630 --> 00:00:14.030
we're going to think about strategies
00:00:14.030 --> 00:00:18.000
that plants will use for
reproductive success.
00:00:18.000 --> 00:00:21.170
A plant that has more surviving offspring
00:00:21.170 --> 00:00:24.640
has a higher reproductive success.
00:00:24.640 --> 00:00:26.970
So one major strategy that plants use
00:00:26.970 --> 00:00:30.540
to increase their chances of reproduction
00:00:30.540 --> 00:00:34.680
is by leveraging animals for pollination.
00:00:34.680 --> 00:00:36.640
You have seen pollination.
00:00:36.640 --> 00:00:38.840
This is a picture of
a bee gathering nectar
00:00:38.840 --> 00:00:42.210
from this flower, but as
it gathers that nectar,
00:00:42.210 --> 00:00:44.630
pollen also gets attached to that bee.
00:00:44.630 --> 00:00:47.500
So as that bee goes from flower to flower,
00:00:47.500 --> 00:00:50.460
from plant to plant,
it's able to pollinate,
00:00:50.460 --> 00:00:52.920
it's able to take pollen from one plant
00:00:52.920 --> 00:00:54.660
and give it to another plant,
00:00:54.660 --> 00:00:57.740
allowing for that genetic mixing to occur
00:00:57.740 --> 00:01:01.410
and also to then have
more plant reproduction.
00:01:01.410 --> 00:01:04.340
Now, once a plant is able to reproduce,
00:01:04.340 --> 00:01:06.440
we also need to think about how viable
00:01:06.440 --> 00:01:08.320
its offspring are going to be.
00:01:08.320 --> 00:01:10.700
Are they in conditions
where they are likely
00:01:10.700 --> 00:01:14.890
to succeed in living and
then reproducing themselves?
00:01:14.890 --> 00:01:17.130
And here, a common strategy,
00:01:17.130 --> 00:01:20.350
or at least a category of
strategies that plants use
00:01:20.350 --> 00:01:24.380
are known as seed dispersal.
00:01:24.380 --> 00:01:27.130
And it's really just
trying to get the seeds
00:01:27.130 --> 00:01:28.910
in as many places as possible,
00:01:28.910 --> 00:01:32.030
potentially far away
from the plant itself,
00:01:32.030 --> 00:01:34.290
to increase the chances
that more of the seeds
00:01:34.290 --> 00:01:36.800
are going to be in places
that are nutrient rich,
00:01:36.800 --> 00:01:38.600
where they can survive.
00:01:38.600 --> 00:01:41.800
And once again, you have likely seen this.
00:01:41.800 --> 00:01:45.880
This is a dandelion plant
and when a strong wind blows,
00:01:45.880 --> 00:01:48.210
these dandelion seeds catch the wind
00:01:48.210 --> 00:01:49.210
because they have these structures
00:01:49.210 --> 00:01:51.120
which are not that aerodynamic,
00:01:51.120 --> 00:01:54.300
which pull the seeds along
and can transport them
00:01:54.300 --> 00:01:56.440
for even miles and miles.
00:01:56.440 --> 00:01:59.280
Many of these seeds aren't going
to end up in useful places,
00:01:59.280 --> 00:02:00.650
but some of them might,
00:02:00.650 --> 00:02:02.600
and they might be in places where
00:02:02.600 --> 00:02:06.070
the future dandelion offspring
are more likely to survive
00:02:06.070 --> 00:02:08.435
and then reproduce themselves.
00:02:08.435 --> 00:02:11.593
But seed dispersal also
gets the help of animals.
00:02:12.490 --> 00:02:15.000
This right over here
is a picture of a bird
00:02:15.000 --> 00:02:16.840
eating fruit from a plant.
00:02:16.840 --> 00:02:20.190
And as that bird flies away
and munches on that fruit,
00:02:20.190 --> 00:02:22.060
that seed might be dispersed,
00:02:22.060 --> 00:02:25.330
it might be thrown down hundreds of yards
00:02:25.330 --> 00:02:28.100
or even miles away from
the original plant.
00:02:28.100 --> 00:02:30.380
In many cases, you might eat a fruit,
00:02:30.380 --> 00:02:32.880
and I am saying you, because
we do this ourselves.
00:02:32.880 --> 00:02:35.610
You might eat, say, a
watermelon or a papaya
00:02:35.610 --> 00:02:38.430
and a couple of seeds go
down while you ate it.
00:02:38.430 --> 00:02:41.130
And then later on, you
or some other animal
00:02:41.130 --> 00:02:44.470
might poop it someplace where
it might be a good place
00:02:44.470 --> 00:02:48.560
for that watermelon plant or
that papaya plant to grow.
00:02:48.560 --> 00:02:49.770
So this was just an overview
00:02:49.770 --> 00:02:52.430
of some of the strategies that plants use,
00:02:52.430 --> 00:02:55.400
but it's important to realize
that throughout nature,
00:02:55.400 --> 00:02:58.940
we see this idea of reproductive success
00:02:58.940 --> 00:03:01.880
over and over again, and
in animals' behaviors
00:03:01.880 --> 00:03:04.080
or strategies for reproductive success,
00:03:04.080 --> 00:03:09.080
and here we saw plants' strategies
for reproductive success.
|
Animal behavior and offspring success | https://www.youtube.com/watch?v=txrCIhujs0g | vtt | https://www.youtube.com/api/timedtext?v=txrCIhujs0g&ei=xFWUZZWFErO5mLAPiq2-mA8&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245300&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=D82E111E38CED201604A84DCA3C716DE97B293BB.6E7BCF0E8A4A7EEB6A8CC4F7427B227E98712BF8&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.500 --> 00:00:04.500
- Let's talk a little bit
about reproductive success,
00:00:04.500 --> 00:00:08.415
which is related to the
number of surviving offspring
00:00:08.415 --> 00:00:11.670
that an animal has during its lifetime.
00:00:11.670 --> 00:00:14.690
An animal that has more
surviving offspring
00:00:14.690 --> 00:00:17.378
has a higher reproductive success.
00:00:17.378 --> 00:00:19.781
Now, there's two broad categories
00:00:19.781 --> 00:00:21.905
of traits or behaviors
00:00:21.905 --> 00:00:24.990
that might drive reproductive success.
00:00:24.990 --> 00:00:28.350
One might be behaviors
that increase the chances
00:00:28.350 --> 00:00:30.970
of an animal producing offspring.
00:00:30.970 --> 00:00:33.060
And we know that most
animals that we study,
00:00:33.060 --> 00:00:37.010
not all, but most, reproduce
via sexual reproduction.
00:00:37.010 --> 00:00:37.860
To do that,
00:00:37.860 --> 00:00:41.300
they need to mate with an
individual of the opposite sex.
00:00:41.300 --> 00:00:44.379
And that's why you see
things like peacocks,
00:00:44.379 --> 00:00:48.070
where these very elaborate
feathers are a way
00:00:48.070 --> 00:00:51.130
of signaling to members
of the opposite sex,
00:00:51.130 --> 00:00:55.760
the peahens, that this peacock
here has favorable traits,
00:00:55.760 --> 00:00:59.200
is attractive to the
peahen, has good health,
00:00:59.200 --> 00:01:00.980
which signals to the peahen
00:01:00.980 --> 00:01:02.750
that by reproducing with this peacock,
00:01:02.750 --> 00:01:06.180
they're more likely to
have reproductive success.
00:01:06.180 --> 00:01:07.390
They'll have healthier offspring,
00:01:07.390 --> 00:01:09.450
which are more likely to survive,
00:01:09.450 --> 00:01:12.340
which are more likely to
then go on and reproduce.
00:01:12.340 --> 00:01:14.790
And then assuming that
animals are able to mate
00:01:14.790 --> 00:01:16.166
and able to reproduce,
00:01:16.166 --> 00:01:19.358
another behavior that you
will see amongst animals
00:01:19.358 --> 00:01:21.420
that will increase the chances
00:01:21.420 --> 00:01:22.765
that their offspring will survive,
00:01:22.765 --> 00:01:25.029
and then be able to reproduce themselves
00:01:25.029 --> 00:01:27.350
is parental care,
00:01:27.350 --> 00:01:30.695
or behaviors that protect
offspring from predators.
00:01:30.695 --> 00:01:33.640
You see that throughout
the animal kingdom.
00:01:33.640 --> 00:01:36.330
Here are some emperor penguins taking care
00:01:36.330 --> 00:01:39.110
of their young baby penguin.
00:01:39.110 --> 00:01:42.540
Here is a mother grizzly bear
taking care of her bears.
00:01:42.540 --> 00:01:46.320
And here the parental care
might be helping them find food,
00:01:46.320 --> 00:01:48.660
giving them food, training them,
00:01:48.660 --> 00:01:50.780
protecting them from other predators
00:01:50.780 --> 00:01:52.510
or from competitors in some way.
00:01:52.510 --> 00:01:54.970
And this isn't just amongst
bears, and penguins,
00:01:54.970 --> 00:01:56.990
and potentially peacocks and peahens.
00:01:56.990 --> 00:01:59.780
It's all in service to,
at least in some level,
00:01:59.780 --> 00:02:01.833
reproductive success.
|
Earth's changing climate | https://www.youtube.com/watch?v=z9xKxciHgo8 | vtt | https://www.youtube.com/api/timedtext?v=z9xKxciHgo8&ei=xFWUZceDF_nXxN8P0ra8gAI&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245300&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=6C81092496B3722AA6B3F3825952AB96B1139293.7E3CFBE93DF2601B6F157D550A0DC26B65E07007&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.000 --> 00:00:01.250
- [Narrator] Have you
ever tried to imagine
00:00:01.250 --> 00:00:03.760
what the world was like
in the distant past?
00:00:03.760 --> 00:00:06.390
Maybe you'd like to explore
the age of the dinosaurs
00:00:06.390 --> 00:00:08.790
when the earth was much
hotter than it was today.
00:00:08.790 --> 00:00:09.850
Perhaps you'd prefer
00:00:09.850 --> 00:00:12.340
when temperatures dropped
too much colder than today.
00:00:12.340 --> 00:00:14.900
You could track a mammoth
alongside our early ancestors
00:00:14.900 --> 00:00:17.740
who evolved around the
end of the last ice age.
00:00:17.740 --> 00:00:19.730
We know about all of these
ancient climate trends
00:00:19.730 --> 00:00:20.760
because scientists learned
00:00:20.760 --> 00:00:23.290
how to estimate them using
evidence from ice cores,
00:00:23.290 --> 00:00:25.363
tree rings, and other natural phenomena.
00:00:26.230 --> 00:00:28.050
We now know that for
most of human history,
00:00:28.050 --> 00:00:29.190
people could expect a pattern
00:00:29.190 --> 00:00:30.500
that looks something like this graph
00:00:30.500 --> 00:00:33.160
from the National Aeronautics
and Space Administration
00:00:33.160 --> 00:00:35.330
which shows how temperatures
changed each year
00:00:35.330 --> 00:00:37.120
in comparison to this line,
00:00:37.120 --> 00:00:39.500
which represents the average
global annual temperature
00:00:39.500 --> 00:00:42.300
from 1880 to 1899.
00:00:42.300 --> 00:00:45.210
When we look at the time
period between 1880 and 1940,
00:00:45.210 --> 00:00:47.450
we can see that some years
temperatures would be higher
00:00:47.450 --> 00:00:49.770
than this average, some
years they would be lower,
00:00:49.770 --> 00:00:51.130
but they generally swing back
00:00:51.130 --> 00:00:53.080
to a pretty comfortable state.
00:00:53.080 --> 00:00:54.450
Around the 1950s, though,
00:00:54.450 --> 00:00:56.060
the global average
temperature began to climb
00:00:56.060 --> 00:00:57.850
to unprecedented levels.
00:00:57.850 --> 00:00:59.820
Our ancient temperature
records never showed
00:00:59.820 --> 00:01:01.680
such a sudden increase.
00:01:01.680 --> 00:01:04.220
When we look at the time
period from 1950 to today,
00:01:04.220 --> 00:01:05.560
we can see that while temperatures
00:01:05.560 --> 00:01:07.120
still swing back down some years,
00:01:07.120 --> 00:01:08.960
these colder years are still much hotter
00:01:08.960 --> 00:01:11.320
than the average temperatures in the past.
00:01:11.320 --> 00:01:13.700
Researchers noticed a
change in the concentration
00:01:13.700 --> 00:01:16.120
of greenhouse gases in
the Earth's atmosphere.
00:01:16.120 --> 00:01:17.760
These greenhouse gases trap heat
00:01:17.760 --> 00:01:19.140
from the sun in our atmosphere,
00:01:19.140 --> 00:01:21.480
similar to how a
greenhouse allows sunlight
00:01:21.480 --> 00:01:22.830
to pass through its glass walls
00:01:22.830 --> 00:01:25.490
but prevents the heat
it creates from leaving.
00:01:25.490 --> 00:01:27.800
This greenhouse effect is
what keeps our planet warm
00:01:27.800 --> 00:01:29.430
and habitable enough for life.
00:01:29.430 --> 00:01:31.920
However, the amount of one
particular greenhouse gas
00:01:31.920 --> 00:01:34.960
was rising, carbon dioxide or CO2.
00:01:34.960 --> 00:01:37.880
CO2 is naturally one of the
most notable greenhouse gases
00:01:37.880 --> 00:01:38.970
besides water vapor,
00:01:38.970 --> 00:01:41.620
but we can also release
CO2 by burning wood
00:01:41.620 --> 00:01:43.760
or fossil fuels like coal and oil.
00:01:43.760 --> 00:01:46.390
Over time, humans have
increasingly relied on these fuels
00:01:46.390 --> 00:01:48.900
to power things like
planes, cars, and trains
00:01:48.900 --> 00:01:51.200
as well as to generate electricity.
00:01:51.200 --> 00:01:52.740
As a result of these human activities,
00:01:52.740 --> 00:01:55.040
more CO2 is being released
into the atmosphere
00:01:55.040 --> 00:01:56.280
than ever before,
00:01:56.280 --> 00:01:58.370
much more than is normally
released by the Earth
00:01:58.370 --> 00:02:00.210
and at a much faster rate.
00:02:00.210 --> 00:02:02.460
The increasingly heavy
blanket of greenhouse gases
00:02:02.460 --> 00:02:04.240
is trapping excess heat in our atmosphere
00:02:04.240 --> 00:02:05.510
rather than allowing more of it
00:02:05.510 --> 00:02:07.430
to radiate into space as normal.
00:02:07.430 --> 00:02:09.900
This is what's causing
Earth's average temperature
00:02:09.900 --> 00:02:11.650
to rise beyond what
scientists would expect
00:02:11.650 --> 00:02:13.690
based on historical patterns.
00:02:13.690 --> 00:02:14.880
While scientists once referred
00:02:14.880 --> 00:02:16.510
to this process as global warming,
00:02:16.510 --> 00:02:19.910
most now prefer the more
general term, climate change.
00:02:19.910 --> 00:02:21.930
A world that's a little
bit warmer on average
00:02:21.930 --> 00:02:23.530
might not seem like such a big deal,
00:02:23.530 --> 00:02:25.340
but we've learned that even a small shift
00:02:25.340 --> 00:02:26.740
in the planet's natural processes
00:02:26.740 --> 00:02:29.360
can have drastic consequences.
00:02:29.360 --> 00:02:31.320
When studying the early
signs of climate change,
00:02:31.320 --> 00:02:33.190
scientists predicted that as cold places
00:02:33.190 --> 00:02:35.010
like North and South Pole got warmer,
00:02:35.010 --> 00:02:36.600
the ice would begin to melt.
00:02:36.600 --> 00:02:39.110
All of that frozen water
suddenly flowing into the oceans
00:02:39.110 --> 00:02:40.460
would cause sea levels to rise,
00:02:40.460 --> 00:02:43.340
which would affect the
planet's weather system.
00:02:43.340 --> 00:02:45.070
Have you heard all the
news about weird weather
00:02:45.070 --> 00:02:46.410
in the past few years?
00:02:46.410 --> 00:02:49.020
Snow in places that's
usually warm and dry,
00:02:49.020 --> 00:02:52.060
or drought in places that
are usually cold and rainy,
00:02:52.060 --> 00:02:54.860
huge fires during extremely hot summers,
00:02:54.860 --> 00:02:58.570
severe storms battering
coastlines and flooding cities.
00:02:58.570 --> 00:03:00.770
Many of these natural hazards
used to be somewhat rare,
00:03:00.770 --> 00:03:02.480
but now they're becoming more common,
00:03:02.480 --> 00:03:05.020
exactly as climate scientists predicted.
00:03:05.020 --> 00:03:07.440
People have relied on relatively
consistent weather patterns
00:03:07.440 --> 00:03:08.350
for generations,
00:03:08.350 --> 00:03:09.730
so they aren't prepared to adapt
00:03:09.730 --> 00:03:11.870
to these changes in
their local environment.
00:03:11.870 --> 00:03:13.560
Communities that are
already feeling the effects
00:03:13.560 --> 00:03:14.930
of climate change are worried
00:03:14.930 --> 00:03:16.130
that they're gonna lose their homes,
00:03:16.130 --> 00:03:19.193
their livelihoods, or their
sources of food and water.
00:03:20.500 --> 00:03:21.940
Scientists are working on technologies
00:03:21.940 --> 00:03:23.820
that can help us remove
some of the excess CO2
00:03:23.820 --> 00:03:24.710
from the atmosphere,
00:03:24.710 --> 00:03:27.470
but in the meantime they
recommend that we emit less CO2
00:03:27.470 --> 00:03:28.650
in the first place.
00:03:28.650 --> 00:03:29.790
This would allow us to limit
00:03:29.790 --> 00:03:31.780
how much the global average
temperature increases,
00:03:31.780 --> 00:03:33.200
giving communities time to adapt
00:03:33.200 --> 00:03:35.170
to changes in their surroundings.
00:03:35.170 --> 00:03:36.520
Of course, it's complicated
00:03:36.520 --> 00:03:38.570
to change the way our societies work.
00:03:38.570 --> 00:03:40.140
To help reduce CO2 emissions,
00:03:40.140 --> 00:03:41.610
you may see some people advocating
00:03:41.610 --> 00:03:43.210
for tweaking individual behaviors,
00:03:43.210 --> 00:03:44.670
like eating plant-based diets
00:03:44.670 --> 00:03:47.420
or using low carbon
transportation methods.
00:03:47.420 --> 00:03:49.810
You may see others saying
that since large organizations
00:03:49.810 --> 00:03:52.230
in highly populated
countries emit the most CO2,
00:03:52.230 --> 00:03:53.160
we need to push them
00:03:53.160 --> 00:03:56.050
to make more wide raging
institutional changes.
00:03:56.050 --> 00:03:57.750
As someone who works in
environmental science,
00:03:57.750 --> 00:03:59.880
I know that sorting through
all of these different facts
00:03:59.880 --> 00:04:03.170
and opinions on climate
change can be overwhelming.
00:04:03.170 --> 00:04:04.990
It's difficult to think
about living in a world
00:04:04.990 --> 00:04:06.140
that may be very different
00:04:06.140 --> 00:04:08.210
from what I've always known in the past.
00:04:08.210 --> 00:04:09.250
I've found it helpful
00:04:09.250 --> 00:04:12.030
to both adopt simple sustainable
habits in my own life,
00:04:12.030 --> 00:04:13.820
while also seeking out community groups
00:04:13.820 --> 00:04:15.490
that work on bigger initiatives.
00:04:15.490 --> 00:04:17.100
It's easier to imagine the future
00:04:17.100 --> 00:04:19.510
when you help others to shape it.
00:04:19.510 --> 00:04:21.950
Now that we've taken some time
to think about Earth's past
00:04:21.950 --> 00:04:23.880
and what's happening to it in the present,
00:04:23.880 --> 00:04:26.150
try looking towards the
future of our planet.
00:04:26.150 --> 00:04:27.850
What is your ideal future?
00:04:27.850 --> 00:04:29.800
And how can you help to make it happen?
|
Weathering and erosion | https://www.youtube.com/watch?v=xWWOHttrkWI | vtt | https://www.youtube.com/api/timedtext?v=xWWOHttrkWI&ei=xFWUZeeMItiLp-oPipqV8As&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245300&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=1EA38B3B44ED516E6120814B538D5EDDE416FEE0.4D2DA41A684C00AD0ADA132C57D7E587DFF8A7F3&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.380 --> 00:00:02.250
- [Instructor] Growing
up in Southern Idaho,
00:00:02.250 --> 00:00:05.450
one of my favorite places
to visit was Swan Falls,
00:00:05.450 --> 00:00:08.710
a gorgeous canyon formed
by the snake river.
00:00:08.710 --> 00:00:11.400
All throughout my childhood,
I remember scrambling
00:00:11.400 --> 00:00:13.430
over the boulders down in this canyon
00:00:13.430 --> 00:00:16.560
and playing in the cool water
at the edge of the river.
00:00:16.560 --> 00:00:18.800
Over thousands and thousands of years,
00:00:18.800 --> 00:00:21.690
water slowly eroded
away rock and sediment.
00:00:21.690 --> 00:00:26.660
Water made this canyon and
water forms many landscapes,
00:00:26.660 --> 00:00:30.900
including valleys, ravines,
cliffs, coastlines,
00:00:30.900 --> 00:00:34.940
all of these were largely
shaped and affected by water.
00:00:34.940 --> 00:00:37.670
And given that water
covers most of the earth,
00:00:37.670 --> 00:00:39.990
or over 70% of it,
00:00:39.990 --> 00:00:43.430
it's no surprise that water
also shapes the earth.
00:00:43.430 --> 00:00:45.310
Water is a powerful force.
00:00:45.310 --> 00:00:47.390
It can literally wash away soil
00:00:47.390 --> 00:00:49.900
and carve away rock bit by bit,
00:00:49.900 --> 00:00:53.570
which scientists describe
through two separate processes.
00:00:53.570 --> 00:00:57.490
When water breaks rocks
apart, it's called weathering.
00:00:57.490 --> 00:01:00.830
And when water carries away
surface soil, sediments,
00:01:00.830 --> 00:01:03.683
and that broken down
rock it's called erosion.
00:01:04.810 --> 00:01:07.550
Erosion by water starts with rain.
00:01:07.550 --> 00:01:09.320
During a rain storm the impact
00:01:09.320 --> 00:01:11.710
of raindrops is actually powerful enough
00:01:11.710 --> 00:01:15.730
to dislodge soil particles
and damage soil structure.
00:01:15.730 --> 00:01:18.380
This is called mechanical weathering.
00:01:18.380 --> 00:01:20.460
As rainwater starts to accumulate,
00:01:20.460 --> 00:01:22.640
it can erode a landscape by moving soil
00:01:22.640 --> 00:01:24.880
and rock particles, called sediment,
00:01:24.880 --> 00:01:27.480
away from their original location.
00:01:27.480 --> 00:01:31.280
And as water flows down the
slope of hills and mountains,
00:01:31.280 --> 00:01:34.180
it transports sediment along with it.
00:01:34.180 --> 00:01:36.750
Eventually water gathers
into small streams
00:01:36.750 --> 00:01:40.460
and then rivers, carrying
more and more sediment.
00:01:40.460 --> 00:01:44.320
In fact, through erosion,
water carries away billions
00:01:44.320 --> 00:01:47.540
of tons of sediment to
the oceans every year.
00:01:47.540 --> 00:01:50.590
Plant roots and vegetation
can hold soil in place
00:01:50.590 --> 00:01:53.190
and prevent or slow soil erosion.
00:01:53.190 --> 00:01:56.000
But if soil has nothing to hold it down,
00:01:56.000 --> 00:01:58.643
water can erode away soil very quickly.
00:02:00.460 --> 00:02:02.710
As the volume of water increases,
00:02:02.710 --> 00:02:05.290
so does its power of erosion.
00:02:05.290 --> 00:02:08.320
In turn, a large river can erode more soil
00:02:08.320 --> 00:02:11.320
and rock quicker than a small river can.
00:02:11.320 --> 00:02:13.050
The speed of the water flow
00:02:13.050 --> 00:02:15.630
also affects its erosional power.
00:02:15.630 --> 00:02:19.900
Simply put, faster moving
water can carry more sediment.
00:02:19.900 --> 00:02:22.940
This relationship is one
reason why fast moving water
00:02:22.940 --> 00:02:25.500
causes more erosion than the same volume
00:02:25.500 --> 00:02:27.460
of slow moving water.
00:02:27.460 --> 00:02:31.190
A great example of water
erosion in relation to speed
00:02:31.190 --> 00:02:34.330
is that of meandering
rivers and Oxbow lakes.
00:02:34.330 --> 00:02:38.130
You know, the weird horseshoe
looking lake in this image.
00:02:38.130 --> 00:02:41.310
Let's take a look at how
these Oxbow lakes form.
00:02:41.310 --> 00:02:43.560
The current of the water is fastest
00:02:43.560 --> 00:02:45.730
on the outside of the bend.
00:02:45.730 --> 00:02:48.410
In turn, these are the
areas where water tends
00:02:48.410 --> 00:02:50.630
to erode away the river bank.
00:02:50.630 --> 00:02:53.680
Conversely, the current
of the water is slowest
00:02:53.680 --> 00:02:55.510
on the inside of a bend.
00:02:55.510 --> 00:02:58.600
Here, the water slows
down so much that some
00:02:58.600 --> 00:03:01.370
of the sediment that is
being carried is dropped,
00:03:01.370 --> 00:03:02.920
or deposited.
00:03:02.920 --> 00:03:04.863
This is called sedimentation.
00:03:05.740 --> 00:03:08.200
Over time, through erosion and deposition,
00:03:08.200 --> 00:03:09.900
an Oxbow lake will form,
00:03:09.900 --> 00:03:12.050
which is eventually
cut off from the river.
00:03:13.330 --> 00:03:15.070
Chemical weathering as another way
00:03:15.070 --> 00:03:16.990
that water can break rocks,
00:03:16.990 --> 00:03:19.720
such as when acids in water
dissolve certain types
00:03:19.720 --> 00:03:21.300
of rocks and minerals.
00:03:21.300 --> 00:03:24.040
Over time, flowing water
can dissolve the minerals
00:03:24.040 --> 00:03:27.020
and rocks on or under the surface.
00:03:27.020 --> 00:03:29.470
This chemical weathering
can cause sinkholes,
00:03:29.470 --> 00:03:31.630
caves, and cliffs to form.
00:03:31.630 --> 00:03:33.540
Certain rocks like limestone
00:03:33.540 --> 00:03:36.430
are especially vulnerable to erosion.
00:03:36.430 --> 00:03:39.280
In particular, limestone easily erodes due
00:03:39.280 --> 00:03:41.280
to carbonic acid and rainwater,
00:03:41.280 --> 00:03:44.530
which forms when carbon dioxide, or CO2,
00:03:44.530 --> 00:03:46.980
from the atmosphere dissolves in water.
00:03:46.980 --> 00:03:49.250
In turn limestone erosion can produce
00:03:49.250 --> 00:03:50.933
intricate cave systems.
00:03:53.050 --> 00:03:55.030
Along beaches and the ocean front,
00:03:55.030 --> 00:03:58.140
coastal erosion breaks
up and wears away rock.
00:03:58.140 --> 00:04:00.450
As waves sweep in over and over,
00:04:00.450 --> 00:04:03.103
they cause rock to weather
away and break off.
00:04:05.970 --> 00:04:08.570
Going back to the Snake
River and Swan Falls,
00:04:08.570 --> 00:04:12.089
I can see examples of weathering
and erosion all around me.
00:04:12.089 --> 00:04:15.090
I look to the cliffs which
have been slowly carved away
00:04:15.090 --> 00:04:18.920
by the Snake River over time
to reveal this amazing valley,
00:04:18.920 --> 00:04:22.460
which was formed by
weathering and water erosion.
00:04:22.460 --> 00:04:24.930
Water erosion is incredibly powerful
00:04:24.930 --> 00:04:28.380
and although it can be
destructive by removing soil
00:04:28.380 --> 00:04:31.630
and rock over thousands
and thousands of years,
00:04:31.630 --> 00:04:33.480
water erosion is also responsible
00:04:33.480 --> 00:04:34.820
for creating the beautiful
00:04:34.820 --> 00:04:37.643
and spectacular landscapes
that we enjoy today.
|
The rock cycle | https://www.youtube.com/watch?v=rmH4W92eHVM | vtt | https://www.youtube.com/api/timedtext?v=rmH4W92eHVM&ei=xFWUZb-LFKyDp-oPvsCy0AQ&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245300&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=08EE705CA3D44222956DCEECCF029B8F708CF2CD.0EC4C63F725DBD4A9C573E17809674E86559416E&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.170 --> 00:00:01.100
- [Instructor] Have you ever tried
00:00:01.100 --> 00:00:03.490
to hold a staring contest with a rock?
00:00:03.490 --> 00:00:06.500
If you did, you might not have
expected that all that time
00:00:06.500 --> 00:00:08.370
you were staring at one of the sneakiest
00:00:08.370 --> 00:00:10.470
shape-shifters in the world.
00:00:10.470 --> 00:00:13.570
No, rocks don't shapeshift into unicorns,
00:00:13.570 --> 00:00:16.530
but they do change shape and composition.
00:00:16.530 --> 00:00:18.450
Sometimes they change quickly,
00:00:18.450 --> 00:00:20.110
like when an interrupting volcano
00:00:20.110 --> 00:00:22.340
launches molten rock into the air.
00:00:22.340 --> 00:00:24.290
And sometimes they change slowly,
00:00:24.290 --> 00:00:26.400
like when a rock is heated and compressed
00:00:26.400 --> 00:00:29.770
in the earth for thousands
to millions of years.
00:00:29.770 --> 00:00:31.480
When geologists stare at a rock,
00:00:31.480 --> 00:00:33.760
they can figure out the rocks composition
00:00:33.760 --> 00:00:36.280
and tell the story of how it was created.
00:00:36.280 --> 00:00:40.130
And it turns out rocks can be
made in many different ways.
00:00:40.130 --> 00:00:42.930
When put it the right
combination of heat and pressure,
00:00:42.930 --> 00:00:45.460
rocks can become molten and liquid.
00:00:45.460 --> 00:00:48.480
When this molten rock
cools and becomes solid,
00:00:48.480 --> 00:00:50.960
we call the rock it makes igneous rock.
00:00:50.960 --> 00:00:53.420
This term comes from
the Latin word igneus,
00:00:53.420 --> 00:00:56.250
which means fiery or burning hot.
00:00:56.250 --> 00:00:59.930
Igneous rocks make up more
than 90% of the Earth's crust.
00:00:59.930 --> 00:01:02.630
One common kind of
igneous rock is granite,
00:01:02.630 --> 00:01:04.620
which you've probably seen in bridges,
00:01:04.620 --> 00:01:06.560
buildings, and countertops.
00:01:06.560 --> 00:01:09.390
Another kind of igneous rock is obsidian,
00:01:09.390 --> 00:01:11.290
which is smooth and glassy,
00:01:11.290 --> 00:01:13.740
and is sometimes used
to make knife weights.
00:01:13.740 --> 00:01:16.260
Both of these rocks were
made of molten rock.
00:01:16.260 --> 00:01:18.425
So why do they look so different?
00:01:18.425 --> 00:01:21.120
Well, granite was made from magma,
00:01:21.120 --> 00:01:22.940
which is molten rock that exists
00:01:22.940 --> 00:01:24.560
below the surface of the earth.
00:01:24.560 --> 00:01:27.280
Magma tends to cool slowly underground,
00:01:27.280 --> 00:01:28.840
which gives time for the elements in it
00:01:28.840 --> 00:01:30.490
to form large crystals.
00:01:30.490 --> 00:01:32.909
And this obsidian rock was made from lava,
00:01:32.909 --> 00:01:36.250
which is molten rock that
flows above the ground.
00:01:36.250 --> 00:01:38.220
Lava tends to cool quickly,
00:01:38.220 --> 00:01:41.010
which causes the rocks
it forms like obsidian,
00:01:41.010 --> 00:01:42.960
tuff smaller crystals.
00:01:42.960 --> 00:01:44.520
I always remember the difference
00:01:44.520 --> 00:01:46.690
between magma and lava like this.
00:01:46.690 --> 00:01:48.860
I keep my lava lamp above the ground,
00:01:48.860 --> 00:01:50.940
just like lava is above the ground.
00:01:50.940 --> 00:01:53.330
If I buried my lava lamp in the ground,
00:01:53.330 --> 00:01:55.390
then I can call it a magma lamp.
00:01:55.390 --> 00:01:58.980
Once an igneous rock is
created, its journey isn't over.
00:01:58.980 --> 00:02:00.320
The rock might begin to change
00:02:00.320 --> 00:02:02.000
through a process called weathering.
00:02:02.000 --> 00:02:05.850
This is when water, weather,
wind, and other physical forces
00:02:05.850 --> 00:02:07.100
chip away at a rock
00:02:07.100 --> 00:02:09.170
and cause little pieces to break off.
00:02:09.170 --> 00:02:12.090
These little particles
are called sediments.
00:02:12.090 --> 00:02:13.640
The sediment from our igneous rock
00:02:13.640 --> 00:02:16.060
can be moved around by wind and water.
00:02:16.060 --> 00:02:17.804
This is called erosion.
00:02:17.804 --> 00:02:20.900
Eventually, the sediment
will settle down somewhere.
00:02:20.900 --> 00:02:23.410
Maybe at the bottom of an ocean or a lake,
00:02:23.410 --> 00:02:26.120
and it might join other
sediment from other rocks,
00:02:26.120 --> 00:02:28.430
crushed up shells, and plant matter.
00:02:28.430 --> 00:02:31.570
And over time, this
sediment will become a rock.
00:02:31.570 --> 00:02:33.140
Rocks that are formed from sediments
00:02:33.140 --> 00:02:35.946
are called, you guessed
it, sedimentary rocks.
00:02:35.946 --> 00:02:37.960
But how does sedimentary goop
00:02:37.960 --> 00:02:40.290
at the bottom of the lake become a rock?
00:02:40.290 --> 00:02:43.350
Well, it goes through a
process called lithification.
00:02:43.350 --> 00:02:45.650
Lith comes from the Greek word for stone.
00:02:45.650 --> 00:02:48.690
So you can think of this
process as stonification.
00:02:48.690 --> 00:02:52.120
The first step of lithification
is called deposition.
00:02:52.120 --> 00:02:54.950
This is when sediment is
deposited in a new location
00:02:54.950 --> 00:02:57.342
and it spreads out to form a layer.
00:02:57.342 --> 00:02:59.690
As more and more layers are created,
00:02:59.690 --> 00:03:02.473
the layers underneath them
become squished together.
00:03:03.430 --> 00:03:05.470
This is called compaction.
00:03:05.470 --> 00:03:07.640
When water moves to
the layers of sediment,
00:03:07.640 --> 00:03:10.160
it can carry dissolve minerals with it.
00:03:10.160 --> 00:03:11.750
The water can leave these minerals
00:03:11.750 --> 00:03:13.430
in between the sediment particles,
00:03:13.430 --> 00:03:15.800
which makes everything stick together.
00:03:15.800 --> 00:03:19.650
This cementing of sediment
is called cementation.
00:03:19.650 --> 00:03:22.320
Limestone is a sedimentary
rock that is made with sediment
00:03:22.320 --> 00:03:24.950
that contains a lot of
calcium carbonate in it
00:03:24.950 --> 00:03:26.930
goes through lithification.
00:03:26.930 --> 00:03:29.280
But once the sedimentary
rock has been created,
00:03:29.280 --> 00:03:31.430
it doesn't mean that it is done changing.
00:03:31.430 --> 00:03:34.570
Sometimes a rock is
squeezed or heated so much
00:03:34.570 --> 00:03:37.720
that the minerals inside it
actually change composition.
00:03:37.720 --> 00:03:40.200
It is now a metamorphic rock.
00:03:40.200 --> 00:03:42.440
You might've heard of
the word metamorphosis,
00:03:42.440 --> 00:03:44.040
which describes when something changes
00:03:44.040 --> 00:03:46.180
from one form and structure to another.
00:03:46.180 --> 00:03:48.700
Like when a caterpillar
turns into a butterfly.
00:03:48.700 --> 00:03:51.920
Metamorphic rocks are made
when igneous, sedimentary,
00:03:51.920 --> 00:03:53.746
or even other metamorphic rocks
00:03:53.746 --> 00:03:57.790
change form and structure
because of heat and pressure.
00:03:57.790 --> 00:04:00.070
For example, when the
sedimentary rock, limestone,
00:04:00.070 --> 00:04:02.030
gets put under a lot of heat and pressure,
00:04:02.030 --> 00:04:03.690
it can turn into marble,
00:04:03.690 --> 00:04:06.850
but metamorphic rocks still
may not be done changing.
00:04:06.850 --> 00:04:09.970
Rocks can actually keep
on changing forever.
00:04:09.970 --> 00:04:12.926
Igneous and metamorphic rocks
can become sedimentary rocks
00:04:12.926 --> 00:04:15.330
if they're broken apart into sediments
00:04:15.330 --> 00:04:17.060
and go through lithification.
00:04:17.060 --> 00:04:19.850
And metamorphic rocks
and sedimentary rocks
00:04:19.850 --> 00:04:22.210
can become igneous rocks
when they are melted
00:04:22.210 --> 00:04:23.280
and then cools.
00:04:23.280 --> 00:04:25.530
And igneous rocks and sedimentary rocks
00:04:25.530 --> 00:04:27.110
can become metamorphic rocks
00:04:27.110 --> 00:04:29.320
when they're exposed to
high heat and pressure.
00:04:29.320 --> 00:04:31.600
This is called the rock cycle.
00:04:31.600 --> 00:04:34.310
So maybe next time you get
the chance to stare at a rock.
00:04:34.310 --> 00:04:36.630
See if you can figure
out whether it's igneous,
00:04:36.630 --> 00:04:38.680
metamorphic, or sedimentary.
00:04:38.680 --> 00:04:40.410
And when rocks changed so much,
00:04:40.410 --> 00:04:42.663
who knows what kind of rock it'll be next.
|
The water cycle | https://www.youtube.com/watch?v=r2dnUvP1JgM | vtt | https://www.youtube.com/api/timedtext?v=r2dnUvP1JgM&ei=xFWUZYOFFMebhcIPjJ-66A0&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245300&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=EEACFBA1C9CEDBAAAA5B5F5A8FA90F39244532D5.E6F19E9BE2C7E8BEB9B1B6B5785CAF16079BBA3C&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.360 --> 00:00:02.360
- [Instructor] Did you know
that the water you drink
00:00:02.360 --> 00:00:05.540
is actually the same
water that dinosaurs drank
00:00:05.540 --> 00:00:08.810
over 65 million years ago?
00:00:08.810 --> 00:00:10.350
It might be hard to believe
00:00:10.350 --> 00:00:14.070
but your water is actually
really, really old.
00:00:14.070 --> 00:00:18.080
In fact, water on Earth is
much older than the dinosaurs.
00:00:18.080 --> 00:00:20.300
Scientists estimate
that the water on Earth
00:00:20.300 --> 00:00:24.000
is at least 4.6 billion years old.
00:00:24.000 --> 00:00:26.520
And the amount of water on Earth today,
00:00:26.520 --> 00:00:29.460
in lakes, rivers, oceans, glaciers,
00:00:29.460 --> 00:00:32.190
even under the ground
and up in the clouds,
00:00:32.190 --> 00:00:33.600
it's about the same as it was
00:00:33.600 --> 00:00:35.980
millions and millions of years ago.
00:00:35.980 --> 00:00:38.220
That's because water is recycled.
00:00:38.220 --> 00:00:40.583
It just gets used again and again.
00:00:41.580 --> 00:00:43.690
And that brings us to the water cycle,
00:00:43.690 --> 00:00:46.170
which is how water continuously moves
00:00:46.170 --> 00:00:49.590
from the ground to the
atmosphere and back again.
00:00:49.590 --> 00:00:53.890
And as water moves through
the cycle, it changes form.
00:00:53.890 --> 00:00:56.870
In fact, water is the
only substance on Earth
00:00:56.870 --> 00:00:59.530
that naturally exists in three states,
00:00:59.530 --> 00:01:02.180
solid, liquid, and gas.
00:01:02.180 --> 00:01:05.160
Have you seen water in all
of its different states?
00:01:05.160 --> 00:01:07.420
Maybe on a hot day, you'll add some ice,
00:01:07.420 --> 00:01:09.470
which is water in its solid state,
00:01:09.470 --> 00:01:11.380
to a glass of liquid water.
00:01:11.380 --> 00:01:13.620
Or maybe when you take out some food
00:01:13.620 --> 00:01:15.460
that you've heated in the microwave,
00:01:15.460 --> 00:01:17.830
you'll see steam coming off of the food,
00:01:17.830 --> 00:01:20.913
which is water in its
gas state as water vapor.
00:01:21.820 --> 00:01:23.010
When you think of water,
00:01:23.010 --> 00:01:25.720
you might think of the wide open ocean.
00:01:25.720 --> 00:01:29.710
Over 95% of all the water
on Earth is in the ocean,
00:01:29.710 --> 00:01:33.150
so this is a great place to
start with the water cycle.
00:01:33.150 --> 00:01:35.960
Here, energy from the sun warms up water
00:01:35.960 --> 00:01:37.690
on the surface of the ocean
00:01:37.690 --> 00:01:40.260
enough to turn it into water vapor.
00:01:40.260 --> 00:01:42.730
This is called evaporation.
00:01:42.730 --> 00:01:44.890
This water vapor is less dense,
00:01:44.890 --> 00:01:47.690
meaning it's lighter, than liquid water,
00:01:47.690 --> 00:01:50.770
so it rises up and up into the atmosphere.
00:01:50.770 --> 00:01:53.440
However, as the water vapor rises,
00:01:53.440 --> 00:01:56.000
the temperature in the atmosphere cools.
00:01:56.000 --> 00:01:58.290
In turn, the water vapor condenses
00:01:58.290 --> 00:02:00.670
into tiny liquid water droplets,
00:02:00.670 --> 00:02:03.770
or, as we see them, clouds.
00:02:03.770 --> 00:02:06.210
This is called condensation.
00:02:06.210 --> 00:02:10.540
Air currents then move these
clouds all around the Earth.
00:02:10.540 --> 00:02:14.180
As a cloud collects more and
more liquid water droplets,
00:02:14.180 --> 00:02:16.330
the water may be released from the cloud,
00:02:16.330 --> 00:02:17.820
pulled down by gravity,
00:02:17.820 --> 00:02:19.840
and then return to the ocean or land
00:02:19.840 --> 00:02:22.050
as precipitation, like rain.
00:02:22.050 --> 00:02:23.780
If it's really cold, though,
00:02:23.780 --> 00:02:27.230
the water drops may
crystallize and become snow.
00:02:27.230 --> 00:02:28.940
The snow will fall to the ground
00:02:28.940 --> 00:02:31.070
and eventually melt back into a liquid
00:02:31.070 --> 00:02:34.880
and run off into a lake or
river, pulled down by gravity,
00:02:34.880 --> 00:02:36.970
which flows back into the ocean
00:02:36.970 --> 00:02:39.253
where the whole process starts over again.
00:02:40.150 --> 00:02:43.090
But that's just one path water can take
00:02:43.090 --> 00:02:44.600
through the water cycle.
00:02:44.600 --> 00:02:47.130
It's like a choose your own adventure.
00:02:47.130 --> 00:02:50.320
Instead of snow melting and
running off into a river,
00:02:50.320 --> 00:02:53.670
the snow could become part
of an icy cold glacier
00:02:53.670 --> 00:02:56.430
and stay there for a long, long time,
00:02:56.430 --> 00:02:58.660
for thousands of years.
00:02:58.660 --> 00:03:02.870
Or rain can seep into the
ground and become groundwater,
00:03:02.870 --> 00:03:05.860
where it's then absorbed by plant roots.
00:03:05.860 --> 00:03:08.260
In turn, through transpiration,
00:03:08.260 --> 00:03:10.090
the water absorbed by the plants
00:03:10.090 --> 00:03:12.550
can transition to water vapor
00:03:12.550 --> 00:03:14.550
and leave directly through the leaves
00:03:14.550 --> 00:03:17.150
via tiny holes called stomata
00:03:17.150 --> 00:03:18.913
and return to the atmosphere.
00:03:19.850 --> 00:03:23.250
Or instead of being
absorbed by plant roots,
00:03:23.250 --> 00:03:27.030
the groundwater can work its
way to an underground aquifer
00:03:27.030 --> 00:03:29.953
or a lake, river, or even the ocean.
00:03:31.040 --> 00:03:33.770
There are many different paths for water
00:03:33.770 --> 00:03:37.350
and the water cycle can
be very complicated.
00:03:37.350 --> 00:03:41.060
But it really comes down
to something very simple.
00:03:41.060 --> 00:03:42.700
The amount of water on Earth
00:03:42.700 --> 00:03:44.670
stays pretty constant over time
00:03:44.670 --> 00:03:46.860
and moves from place to place,
00:03:46.860 --> 00:03:49.520
sometimes transitioning between phases,
00:03:49.520 --> 00:03:52.570
depending on things
like weather, geography,
00:03:52.570 --> 00:03:54.693
solar energy, and gravity.
00:03:55.770 --> 00:03:59.220
Now, we know that water is
essential to life on Earth
00:03:59.220 --> 00:04:02.300
and fresh water is an
especially limited resource
00:04:02.300 --> 00:04:04.620
for a growing world population.
00:04:04.620 --> 00:04:07.560
Changes in the water
cycle can impact everyone
00:04:07.560 --> 00:04:09.990
through the economy, energy production,
00:04:09.990 --> 00:04:13.740
health, recreation
transportation, agriculture,
00:04:13.740 --> 00:04:15.980
and of course drinking water.
00:04:15.980 --> 00:04:18.550
And that's why understanding
the water cycle
00:04:18.550 --> 00:04:20.350
is so important.
00:04:20.350 --> 00:04:22.270
That, and it's pretty cool to know
00:04:22.270 --> 00:04:25.220
that you drink the same
water as dinosaurs did.
00:04:25.220 --> 00:04:26.303
Until next time.
|
Earth's place in the universe | https://www.youtube.com/watch?v=Pv0Re0YEEq0 | vtt | https://www.youtube.com/api/timedtext?v=Pv0Re0YEEq0&ei=xFWUZcbUIbGfvdIPhP6F0Ak&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245300&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=571445502DA52E0A61DC253A30DA45D07BA8635C.3EC70E19F92648A8A9EC980995AB6C08D380738C&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.350 --> 00:00:01.230
- [Narrator] Hello, everyone.
00:00:01.230 --> 00:00:02.690
Today, we are going to be talking about
00:00:02.690 --> 00:00:05.420
Earth's place in space.
00:00:05.420 --> 00:00:07.490
So for as long as there have been humans,
00:00:07.490 --> 00:00:09.240
we've been looking up at the stars,
00:00:09.240 --> 00:00:12.660
and wondering about our
place in the universe.
00:00:12.660 --> 00:00:15.480
Our understanding about
this has improved over time,
00:00:15.480 --> 00:00:17.410
and we have developed models
00:00:17.410 --> 00:00:21.320
that can help us understand
something as vast as space.
00:00:21.320 --> 00:00:25.320
Now, models are just a way of
representing a system of ideas
00:00:25.320 --> 00:00:29.260
that help us identify and
understand patterns that we see.
00:00:29.260 --> 00:00:31.540
Models are a tool that can explain,
00:00:31.540 --> 00:00:35.690
and predict what we see in
the world and space around us.
00:00:35.690 --> 00:00:39.330
And as we gain new information,
we can update our models.
00:00:39.330 --> 00:00:42.220
So what kind of model might we construct
00:00:42.220 --> 00:00:46.660
about how Earth interacts with
other bodies in the universe?
00:00:46.660 --> 00:00:48.260
To begin with, every day,
00:00:48.260 --> 00:00:51.730
we can see the sun rise in
the east, and set in the west,
00:00:51.730 --> 00:00:55.230
and other objects in the sky
follow a similar pattern.
00:00:55.230 --> 00:00:57.470
It was logical then for early models
00:00:57.470 --> 00:01:00.350
to consider the Earth
as a stationary object,
00:01:00.350 --> 00:01:03.800
around which all of the universe revolves.
00:01:03.800 --> 00:01:06.350
This is called a geocentric model,
00:01:06.350 --> 00:01:09.720
geo for Earth, and centric for center.
00:01:09.720 --> 00:01:12.090
And this geocentric model was quite good
00:01:12.090 --> 00:01:14.580
at explaining a lot of the
things that we see in the sky,
00:01:14.580 --> 00:01:18.070
like the apparent motion
of the sun and the stars.
00:01:18.070 --> 00:01:21.670
But there were issues with
this geocentric model.
00:01:21.670 --> 00:01:24.740
For example, the motions of
other planets in the sky.
00:01:24.740 --> 00:01:27.910
A planet like Jupiter might
sometimes move backwards
00:01:27.910 --> 00:01:29.460
in the opposite direction,
00:01:29.460 --> 00:01:31.420
which isn't really very well explained
00:01:31.420 --> 00:01:33.770
by this geocentric model.
00:01:33.770 --> 00:01:36.650
Now, when a model doesn't match
our observations like this,
00:01:36.650 --> 00:01:39.790
we can add new pieces
to improve the model.
00:01:39.790 --> 00:01:42.310
So astronomers working
with the geocentric model
00:01:42.310 --> 00:01:44.500
did this by adding smaller cycles
00:01:44.500 --> 00:01:47.820
within the planets'
orbits around the Earth.
00:01:47.820 --> 00:01:50.900
Adding these cycles did help
match the geocentric model
00:01:50.900 --> 00:01:52.430
to the observations,
00:01:52.430 --> 00:01:54.280
but there were many of
these cycles required,
00:01:54.280 --> 00:01:56.010
and there wasn't a good explanation
00:01:56.010 --> 00:01:57.470
for why these cycles existed.
00:01:57.470 --> 00:01:59.850
And there wasn't very
much reasoning for them,
00:01:59.850 --> 00:02:01.522
and they made the model very complicated,
00:02:01.522 --> 00:02:03.563
and not particularly useful.
00:02:04.580 --> 00:02:06.720
Let's pause and talk a
little bit about motion,
00:02:06.720 --> 00:02:09.343
specifically apparent versus actual.
00:02:10.470 --> 00:02:11.970
Imagine you're sitting in a car,
00:02:11.970 --> 00:02:13.750
and driving through a forest.
00:02:13.750 --> 00:02:16.380
To your perspective, as
you look out the window,
00:02:16.380 --> 00:02:18.980
the trees seem to be whizzing by,
00:02:18.980 --> 00:02:21.300
but trees, of course,
are rooted to the ground.
00:02:21.300 --> 00:02:22.840
It's actually you that are moving
00:02:22.840 --> 00:02:25.060
relative to the surface of the Earth.
00:02:25.060 --> 00:02:29.380
This is the difference between
apparent and actual motion.
00:02:29.380 --> 00:02:32.050
So back to our geocentric model.
00:02:32.050 --> 00:02:34.710
Another way to explain some of the issues
00:02:34.710 --> 00:02:36.470
with a model like the geocentric model,
00:02:36.470 --> 00:02:39.480
besides adding evermore
complicated features to it,
00:02:39.480 --> 00:02:42.410
is to in fact, just come
up with a new model.
00:02:42.410 --> 00:02:43.970
And this is what astronomers did.
00:02:43.970 --> 00:02:44.961
The new model that was proposed
00:02:44.961 --> 00:02:49.563
to replace the geocentric model
was the heliocentric model.
00:02:50.652 --> 00:02:53.750
In this model, the Earth
and all the other planets
00:02:53.750 --> 00:02:56.400
actually revolve around the sun.
00:02:56.400 --> 00:02:58.480
Helio means sun.
00:02:58.480 --> 00:03:01.220
This heliocentric model
didn't need complicated
00:03:01.220 --> 00:03:02.400
and unexplained cycles
00:03:02.400 --> 00:03:05.220
to explain the way the other
planets moved across the sky.
00:03:05.220 --> 00:03:08.610
It was an expected outcome
of the planets' orbits.
00:03:08.610 --> 00:03:09.930
Now you may be wondering,
00:03:09.930 --> 00:03:12.130
in this model, the sun is stationary.
00:03:12.130 --> 00:03:13.560
So why does it seem to be
00:03:13.560 --> 00:03:16.190
moving across the Earth's sky each day?
00:03:16.190 --> 00:03:18.480
This is actually also easily explained,
00:03:18.480 --> 00:03:20.160
because the motion of the sun in the sky
00:03:20.160 --> 00:03:23.760
is not actual motion,
it is apparent motion.
00:03:23.760 --> 00:03:26.370
Not only is the Earth
revolving around the sun,
00:03:26.370 --> 00:03:28.010
revolving means orbiting,
00:03:28.010 --> 00:03:31.020
but the Earth is also
spinning on its own axis.
00:03:31.020 --> 00:03:32.670
And so as the surface of the Earth
00:03:32.670 --> 00:03:34.610
moves with its spinning motion,
00:03:34.610 --> 00:03:38.400
it makes it appear as if the
sun is moving across the sky.
00:03:38.400 --> 00:03:39.690
The spinning of the Earth
00:03:39.690 --> 00:03:41.790
actually explains why celestial objects
00:03:41.790 --> 00:03:44.790
appear to rise and set
over the course of a day,
00:03:44.790 --> 00:03:46.890
while the revolution, or orbit,
00:03:46.890 --> 00:03:49.470
around the sun explains
the motion of those objects
00:03:49.470 --> 00:03:51.170
over the course of a year.
00:03:51.170 --> 00:03:53.910
It's important to remember that
while the heliocentric model
00:03:53.910 --> 00:03:55.700
does a better job of explaining
00:03:55.700 --> 00:03:57.180
and predicting our solar system,
00:03:57.180 --> 00:04:00.770
which is what we want models
to do, it is still a model,
00:04:00.770 --> 00:04:03.940
and not a perfect recreation of reality.
00:04:03.940 --> 00:04:06.110
For example, while the heliocentric model
00:04:06.110 --> 00:04:08.320
considers the sun as stationary,
00:04:08.320 --> 00:04:10.950
we know now that the sun
is actually just one star
00:04:10.950 --> 00:04:14.090
of many billions orbiting
the center of our own galaxy.
00:04:14.090 --> 00:04:17.060
And so the sun, along with
the rest of the solar system,
00:04:17.060 --> 00:04:19.290
is in fact, moving.
00:04:19.290 --> 00:04:20.640
To summarize, in this video,
00:04:20.640 --> 00:04:22.610
we talked about how we can use models
00:04:22.610 --> 00:04:25.110
to help us understand
what we see in the sky,
00:04:25.110 --> 00:04:27.670
and Earth's place in space.
00:04:27.670 --> 00:04:28.890
As we learn more,
00:04:28.890 --> 00:04:30.100
we improve our models,
00:04:30.100 --> 00:04:32.170
and we can develop new
ones that do a better job
00:04:32.170 --> 00:04:33.870
of explaining our observations,
00:04:33.870 --> 00:04:35.730
and predicting the world around us,
00:04:35.730 --> 00:04:37.690
such as the change from a geocentric model
00:04:37.690 --> 00:04:40.020
to a heliocentric model.
00:04:40.020 --> 00:04:42.420
The Earth then is a planet
that orbits the sun,
00:04:42.420 --> 00:04:44.450
like the other planets
of the solar system.
00:04:44.450 --> 00:04:46.960
And the sun appears to
move across the sky,
00:04:46.960 --> 00:04:50.300
because the Earth spins on its axis.
00:04:50.300 --> 00:04:51.133
Thanks for watching,
00:04:51.133 --> 00:04:53.463
and I hope you learned a
little bit of something.
|
Organization in the human body | https://www.youtube.com/watch?v=YE2peDF4Zqg | vtt | https://www.youtube.com/api/timedtext?v=YE2peDF4Zqg&ei=xFWUZcbBKdKYvdIP9amkqAQ&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245300&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=788C3539F43830C35BCE0122374E11C0DDA6DCBF.C658DFE95B70A3D398442271BCE099B385EEBED5&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.290 --> 00:00:01.410
- [Instructor] Have you ever thought about
00:00:01.410 --> 00:00:04.260
how incredible the human body is?
00:00:04.260 --> 00:00:06.210
For example, just to name a few things
00:00:06.210 --> 00:00:08.220
that your body's already been doing today.
00:00:08.220 --> 00:00:11.220
You are using your lungs
to take breaths in and out,
00:00:11.220 --> 00:00:13.430
your heart's beating without stopping.
00:00:13.430 --> 00:00:16.100
And your brain is coordinating
your body's functions,
00:00:16.100 --> 00:00:20.040
and at the same time, helping
you understand this video.
00:00:20.040 --> 00:00:22.600
All these body parts are made up of cells,
00:00:22.600 --> 00:00:26.560
which as you might remember,
are the smallest units of life.
00:00:26.560 --> 00:00:29.330
And it's so amazing
that trillions of cells,
00:00:29.330 --> 00:00:31.870
without thoughts or
intentions of their own,
00:00:31.870 --> 00:00:33.620
can come together to form something
00:00:33.620 --> 00:00:36.340
as complex as the human body.
00:00:36.340 --> 00:00:38.460
To help us understand how this occurs,
00:00:38.460 --> 00:00:41.560
we have to understand how
the body is organized.
00:00:41.560 --> 00:00:45.170
The human body has a
hierarchical organization,
00:00:45.170 --> 00:00:47.510
meaning it's made up of nested layers,
00:00:47.510 --> 00:00:50.150
each one more complex than the last.
00:00:50.150 --> 00:00:54.110
In this case, four different
layers make up this hierarchy.
00:00:54.110 --> 00:00:56.510
Cells, which make up tissues.
00:00:56.510 --> 00:00:58.630
Tissues, which make up organs.
00:00:58.630 --> 00:01:01.080
Organs, which make up organ systems.
00:01:01.080 --> 00:01:04.150
And finally organ systems,
which help the human body
00:01:04.150 --> 00:01:06.040
function as a whole.
00:01:06.040 --> 00:01:08.290
So let's start with cells and tissues.
00:01:08.290 --> 00:01:10.570
Cells are the smallest unit of life,
00:01:10.570 --> 00:01:13.250
and the most basic level of organization
00:01:13.250 --> 00:01:14.800
in the human body.
00:01:14.800 --> 00:01:18.740
In the human body, not all
cells look or work the same.
00:01:18.740 --> 00:01:20.810
Instead, they're specialized
00:01:20.810 --> 00:01:22.850
to carry out different functions.
00:01:22.850 --> 00:01:26.960
After cells, the next level
of organization is tissues.
00:01:26.960 --> 00:01:31.790
A tissue is a collection of
similar, specialized cells.
00:01:31.790 --> 00:01:34.840
And all of the cells that make
up a tissue are like a team.
00:01:34.840 --> 00:01:38.100
They work together to ensure
the tissue works properly.
00:01:38.100 --> 00:01:40.550
For instance, this image shows a section
00:01:40.550 --> 00:01:42.650
of the type of epithelial tissue
00:01:42.650 --> 00:01:45.140
that lines the inside of your mouth.
00:01:45.140 --> 00:01:48.950
This particular tissue is
made up of epithelial cells,
00:01:48.950 --> 00:01:51.330
which are specialized to
help protect your mouth
00:01:51.330 --> 00:01:52.920
from wear and tear.
00:01:52.920 --> 00:01:55.740
So the next time you're
eating a pointy tortilla chip,
00:01:55.740 --> 00:02:00.030
remember how important
this epithelial tissue is.
00:02:00.030 --> 00:02:03.240
Next up are organs and organ systems.
00:02:03.240 --> 00:02:06.570
So organs are structures
that are made up of multiple
00:02:06.570 --> 00:02:09.530
different types of tissues,
which all work together
00:02:09.530 --> 00:02:11.320
to help the organ function.
00:02:11.320 --> 00:02:14.970
And an organ system is a group
of organs that work together
00:02:14.970 --> 00:02:18.280
to carry out complex
functions for the body.
00:02:18.280 --> 00:02:21.410
For instance, the lungs
shown here in the diagram
00:02:21.410 --> 00:02:23.870
are made up of several tissue types
00:02:23.870 --> 00:02:26.920
that help them expand and contract.
00:02:26.920 --> 00:02:29.690
These tissue types
include epithelial tissue,
00:02:29.690 --> 00:02:32.490
which is the same type of
tissue we talked about earlier
00:02:32.490 --> 00:02:35.640
in the mouth, and connective tissue.
00:02:35.640 --> 00:02:38.170
And these tissues work
together so that the lungs
00:02:38.170 --> 00:02:41.100
can carry out their role
in the respiratory system,
00:02:41.100 --> 00:02:43.380
which is the organ system that allows us
00:02:43.380 --> 00:02:45.470
to respire or breathe.
00:02:45.470 --> 00:02:49.040
The respiratory system is
made up of multiple organs,
00:02:49.040 --> 00:02:51.650
including the lungs, the trachea,
00:02:51.650 --> 00:02:53.890
the nose and the diaphragm.
00:02:53.890 --> 00:02:55.820
When we breathe, our diaphragm
00:02:55.820 --> 00:02:58.670
which is this muscle
right here, contracts.
00:02:58.670 --> 00:03:01.080
Air is pulled through
our nose and trachea,
00:03:01.080 --> 00:03:02.810
and into our lungs.
00:03:02.810 --> 00:03:06.540
Here, gas exchange happens
and our bodies take in oxygen
00:03:06.540 --> 00:03:08.770
and get rid of carbon dioxide.
00:03:08.770 --> 00:03:12.340
Then our diaphragm relaxes and we exhale.
00:03:12.340 --> 00:03:15.050
The respiratory system,
and other organ systems
00:03:15.050 --> 00:03:17.730
in the body, carry out specific functions
00:03:17.730 --> 00:03:19.910
that work together to keep us alive.
00:03:19.910 --> 00:03:23.820
And they do this mostly
without us even realizing it.
00:03:23.820 --> 00:03:26.190
So it might get a little
tricky to remember
00:03:26.190 --> 00:03:30.500
how all four levels of
organization cells, tissues,
00:03:30.500 --> 00:03:33.490
organs and organ systems
relate to each other.
00:03:33.490 --> 00:03:35.870
I like to think of these
four different levels,
00:03:35.870 --> 00:03:37.740
almost like the Russian nesting dolls
00:03:37.740 --> 00:03:39.710
that fit one inside another.
00:03:39.710 --> 00:03:42.630
With cells being the
smallest doll on the inside.
00:03:42.630 --> 00:03:46.640
So cells make up tissues.
Tissues make up organs.
00:03:46.640 --> 00:03:49.680
And organs make up organ systems.
00:03:49.680 --> 00:03:51.640
All of these components come together
00:03:51.640 --> 00:03:54.060
to make up the human body.
00:03:54.060 --> 00:03:56.680
So I hope you've learned
more about how our body's
00:03:56.680 --> 00:04:00.290
organization helps us
thrive and stay alive.
00:04:00.290 --> 00:04:03.750
So now use your brain to
tell your muscular system
00:04:03.750 --> 00:04:07.180
to move your arm and give
yourself a pat on the back.
00:04:07.180 --> 00:04:09.490
Because your body and its organized
00:04:09.490 --> 00:04:12.893
hierarchical system is really awesome.
|
Cell parts and their functions | https://www.youtube.com/watch?v=TVxtlfUwIY0 | vtt | https://www.youtube.com/api/timedtext?v=TVxtlfUwIY0&ei=xFWUZcibFbuJp-oPrp6j8AY&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245300&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=8702CF890ACCB17494B7C790D9823A4BADC64DC9.43DB165319A25670BBBE4CAAADDB5A2CA78C128E&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.130 --> 00:00:02.200
- [Instructor] So let's
imagine this scenario.
00:00:02.200 --> 00:00:03.210
It's cold outside
00:00:03.210 --> 00:00:05.830
and we want to make a nice hot bowl
00:00:05.830 --> 00:00:07.550
of chicken noodle soup.
00:00:07.550 --> 00:00:10.200
Well, we'd probably need to
get the ingredients first.
00:00:10.200 --> 00:00:11.860
We need some chicken bones
00:00:11.860 --> 00:00:14.930
to give the broth that
distinct chicken flavor,
00:00:14.930 --> 00:00:18.090
some noodles to add
that starchy component,
00:00:18.090 --> 00:00:21.050
carrots and onions to give
some sweetness and color.
00:00:21.050 --> 00:00:24.170
And of course, salt and
pepper to provide seasoning.
00:00:24.170 --> 00:00:26.040
All of these ingredients
would come together
00:00:26.040 --> 00:00:27.580
to make our chicken noodle soup
00:00:27.580 --> 00:00:30.530
the comfort food that so many people love,
00:00:30.530 --> 00:00:32.950
but this video is supposed
to be about cells.
00:00:32.950 --> 00:00:34.460
You know, those tiny things
00:00:34.460 --> 00:00:36.670
that make up all living things on earth.
00:00:36.670 --> 00:00:40.030
So why am I telling
you about chicken soup?
00:00:40.030 --> 00:00:42.790
Well, just like how each
ingredient in chicken soup
00:00:42.790 --> 00:00:45.930
adds something unique to
the soup's overall flavor
00:00:45.930 --> 00:00:48.230
and texture, a cell's different parts
00:00:48.230 --> 00:00:50.720
add something unique and necessary
00:00:50.720 --> 00:00:53.410
for the overall functioning of the cell.
00:00:53.410 --> 00:00:55.790
So, let's take a look at
some of the structures
00:00:55.790 --> 00:00:58.560
inside a cell and see how
their functions come together
00:00:58.560 --> 00:01:03.050
to allow cells to carry out
all the processes of life.
00:01:03.050 --> 00:01:04.890
So let's explore the parts of a cell
00:01:04.890 --> 00:01:06.830
starting with the cell's surface.
00:01:06.830 --> 00:01:09.690
Cells are separated from
their outside environment
00:01:09.690 --> 00:01:11.730
by a cell membrane.
00:01:11.730 --> 00:01:14.250
You can think of the cell
membrane like a fortress gate,
00:01:14.250 --> 00:01:18.020
because it regulates what
comes into and out of the cell,
00:01:18.020 --> 00:01:19.400
and contained within the cell
00:01:19.400 --> 00:01:22.350
is a jelly-like substance
that fills out the cell
00:01:22.350 --> 00:01:24.660
and contains its internal parts,
00:01:24.660 --> 00:01:27.110
this jelly and all the
structures within it
00:01:27.110 --> 00:01:29.790
make up the cell cytoplasm.
00:01:29.790 --> 00:01:31.020
Unlike chicken soup,
00:01:31.020 --> 00:01:32.730
the cell parts in the cytoplasm
00:01:32.730 --> 00:01:34.300
are not just floating around.
00:01:34.300 --> 00:01:36.760
Instead, they're organized
and held in place
00:01:36.760 --> 00:01:39.280
by an internal structural network.
00:01:39.280 --> 00:01:41.790
Some of the parts contained
within the cytoplasm
00:01:41.790 --> 00:01:43.760
are called organelles.
00:01:43.760 --> 00:01:46.180
So what exactly are organelles?
00:01:46.180 --> 00:01:48.880
Well, organelles are small
compartments in the cell
00:01:48.880 --> 00:01:51.700
that have different
structures and functions.
00:01:51.700 --> 00:01:54.740
The word organelle
basically means, mini organ.
00:01:54.740 --> 00:01:57.910
And just like how our bodies
are made up of different organs
00:01:57.910 --> 00:02:00.350
that work together to help us stay alive,
00:02:00.350 --> 00:02:02.890
cells contain different
organelles that work together
00:02:02.890 --> 00:02:05.670
to get things done inside the cell.
00:02:05.670 --> 00:02:08.570
For example, these jellybean
shaped organelles here
00:02:08.570 --> 00:02:10.830
are little energy producing factories
00:02:10.830 --> 00:02:12.730
called mitochondria.
00:02:12.730 --> 00:02:15.230
So mitochondria use chemical reactions
00:02:15.230 --> 00:02:17.110
to break down sugar molecules
00:02:17.110 --> 00:02:19.160
in order to release energy that the cell
00:02:19.160 --> 00:02:21.270
can use for other tasks.
00:02:21.270 --> 00:02:24.460
Another really amazing
organelle is the nucleus.
00:02:24.460 --> 00:02:27.790
You can think of the nucleus
as the information database
00:02:27.790 --> 00:02:28.690
of the cell.
00:02:28.690 --> 00:02:32.290
It contains DNA which
includes the cell's genes.
00:02:32.290 --> 00:02:34.290
Genes are special instructions
00:02:34.290 --> 00:02:37.163
that the cell uses to
carry out its functions.
00:02:38.550 --> 00:02:40.600
Moving over to a plant cell,
00:02:40.600 --> 00:02:44.420
we can see these green
organelles called chloroplasts.
00:02:44.420 --> 00:02:48.020
You might remember that plants
carry out photosynthesis.
00:02:48.020 --> 00:02:51.160
Well, chloroplasts are the
organelle's responsible
00:02:51.160 --> 00:02:52.610
for this process.
00:02:52.610 --> 00:02:55.810
Plants need food to live,
just like animals do.
00:02:55.810 --> 00:02:58.080
And chloroplasts use photosynthesis
00:02:58.080 --> 00:03:01.640
to produce sugars that
plant cells use as food.
00:03:01.640 --> 00:03:04.590
Plant cells also have a layer
outside their cell membrane
00:03:04.590 --> 00:03:05.680
called the cell wall,
00:03:05.680 --> 00:03:08.270
which helps provide
structure for the cell.
00:03:08.270 --> 00:03:11.320
So as you can see, there
are so many different parts
00:03:11.320 --> 00:03:12.930
that make up a single cell.
00:03:12.930 --> 00:03:15.740
There are many, many
organelles present in cells,
00:03:15.740 --> 00:03:19.010
way more than the handful
I mentioned in this video.
00:03:19.010 --> 00:03:20.810
And what's even more mind blowing
00:03:20.810 --> 00:03:23.640
is that these diagrams are
only simplified versions
00:03:23.640 --> 00:03:25.840
of what cells actually look like.
00:03:25.840 --> 00:03:27.210
And just to give you an idea,
00:03:27.210 --> 00:03:30.600
here's a picture of what
a real cell looks like.
00:03:30.600 --> 00:03:32.160
So when we're talking about cells
00:03:32.160 --> 00:03:34.290
and using these diagrams as references,
00:03:34.290 --> 00:03:37.330
keep in mind that these pictures
are only simplified models
00:03:37.330 --> 00:03:38.970
of the real thing.
00:03:38.970 --> 00:03:40.750
To wrap up this video on cell parts,
00:03:40.750 --> 00:03:44.100
let's revisit our delicious
bowl of chicken noodle soup
00:03:44.100 --> 00:03:45.800
that I mentioned at the beginning.
00:03:45.800 --> 00:03:47.160
Each ingredient that we added
00:03:47.160 --> 00:03:49.510
had a unique function that contributed
00:03:49.510 --> 00:03:51.980
to the soup's taste and texture.
00:03:51.980 --> 00:03:54.500
And similarly, our cell's ingredients,
00:03:54.500 --> 00:03:56.560
its organelles and structures,
00:03:56.560 --> 00:03:58.790
each contribute a unique function
00:03:58.790 --> 00:04:00.210
that helps the cell carry out
00:04:00.210 --> 00:04:02.690
all the tasks necessary for life.
00:04:02.690 --> 00:04:04.680
So the next time you find yourself
00:04:04.680 --> 00:04:06.690
in front of a bowl of noodle soup,
00:04:06.690 --> 00:04:10.110
just imagine that you're
eating one enormous cell.
00:04:10.110 --> 00:04:12.823
Now, isn't that something to noodle on?
|
Cells and Organisms | https://www.youtube.com/watch?v=Uiqro5TUyLA | vtt | https://www.youtube.com/api/timedtext?v=Uiqro5TUyLA&ei=xFWUZfjrI4v6mLAP9IizoAE&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245300&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=6C7C20B55AFCB91771EFC6D29D574AB31DD1704D.7894FDA268F42A4816C2F6D9F2D92295EED63182&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.120 --> 00:00:01.010
- [Narrator] Hi, everyone.
00:00:01.010 --> 00:00:01.843
In this video,
00:00:01.843 --> 00:00:03.170
we are going to be talking about
00:00:03.170 --> 00:00:06.060
one of the most fascinating
and complex features
00:00:06.060 --> 00:00:08.630
of life on Earth, cells.
00:00:08.630 --> 00:00:09.610
But before we do,
00:00:09.610 --> 00:00:12.920
I'd like to take us way back
to when I was a little kid.
00:00:12.920 --> 00:00:14.650
Now I know that for me, at least,
00:00:14.650 --> 00:00:17.100
I had a great time playing
with toy building blocks,
00:00:17.100 --> 00:00:18.920
and creating things out of them.
00:00:18.920 --> 00:00:21.940
I used blocks of
different shapes and sizes
00:00:21.940 --> 00:00:24.350
to make all kinds of things like houses,
00:00:24.350 --> 00:00:27.750
cars, even spaceships, and airplanes.
00:00:27.750 --> 00:00:28.700
You're probably thinking,
00:00:28.700 --> 00:00:31.120
what does this have to do with cells?
00:00:31.120 --> 00:00:34.200
Well, cells are considered
the building blocks of life.
00:00:34.200 --> 00:00:37.290
Like my blocks, cells can
come in a variety of shapes,
00:00:37.290 --> 00:00:39.570
and they have different features too.
00:00:39.570 --> 00:00:41.240
They can also stand alone,
00:00:41.240 --> 00:00:43.920
or they can come together
to build something larger.
00:00:43.920 --> 00:00:47.930
So let's dive deeper into this
fascinating topic of cells.
00:00:47.930 --> 00:00:49.978
So all living things, or organisms,
00:00:49.978 --> 00:00:52.650
like you, me, your pet dog,
00:00:52.650 --> 00:00:55.280
the birds in the sky, the fish in the sea,
00:00:55.280 --> 00:00:59.980
all organisms are made of
these basic units called cells.
00:00:59.980 --> 00:01:03.960
Take this moss plant, for
example, if we zoom way in,
00:01:03.960 --> 00:01:07.700
we can see that it's actually
made up of many smaller units.
00:01:07.700 --> 00:01:09.890
These units are cells.
00:01:09.890 --> 00:01:12.510
Each cell contains a flurry of activity,
00:01:12.510 --> 00:01:13.858
as it works to carry out the functions
00:01:13.858 --> 00:01:16.500
that keep the organism alive.
00:01:16.500 --> 00:01:19.780
In fact, cells are the smallest
unit that can carry out
00:01:19.780 --> 00:01:22.400
all the tasks necessary for life.
00:01:22.400 --> 00:01:25.890
For instance, all cells can
take up nutrients and water,
00:01:25.890 --> 00:01:28.700
get rid of waste, use energy,
00:01:28.700 --> 00:01:30.241
and interact with the things around them
00:01:30.241 --> 00:01:32.500
in their environment.
00:01:32.500 --> 00:01:35.250
These functions, plus many
others that cells carry out,
00:01:35.250 --> 00:01:37.680
are what make life possible.
00:01:37.680 --> 00:01:39.240
There are many different kinds of cells.
00:01:39.240 --> 00:01:40.618
For instance, take a look at these cells
00:01:40.618 --> 00:01:43.050
that make up an onion's outer skin,
00:01:43.050 --> 00:01:45.060
or these really cool red blood cells,
00:01:45.060 --> 00:01:47.120
or even these bacterial cells.
00:01:47.120 --> 00:01:49.840
This type of bacteria is called e-coli,
00:01:49.840 --> 00:01:52.050
which you might've heard
can be a safety hazard
00:01:52.050 --> 00:01:53.370
found in our food.
00:01:53.370 --> 00:01:55.630
So cells are fascinating to look at,
00:01:55.630 --> 00:01:58.620
but we generally can't see
them with our eyes alone.
00:01:58.620 --> 00:01:59.960
Most cells are so small
00:01:59.960 --> 00:02:02.340
that we need a microscope to see them.
00:02:02.340 --> 00:02:04.620
In fact, all of these
pictures of cells here
00:02:04.620 --> 00:02:07.750
were taken with the aid of microscopes.
00:02:07.750 --> 00:02:09.810
And something else that I find really cool
00:02:09.810 --> 00:02:13.500
is that some organisms are
made up of only a single cell,
00:02:13.500 --> 00:02:16.400
while others are made up of many cells.
00:02:16.400 --> 00:02:18.720
So organisms that are made up of one cell
00:02:18.720 --> 00:02:20.440
are called unicellular,
00:02:20.440 --> 00:02:23.230
and organisms that are
made up of many cells
00:02:23.230 --> 00:02:25.130
are called multicellular.
00:02:25.130 --> 00:02:27.540
Uni telling us that
there is only one cell,
00:02:27.540 --> 00:02:30.890
and multi telling us that
there are many cells.
00:02:30.890 --> 00:02:33.410
So an example of a unicellular organism
00:02:33.410 --> 00:02:37.000
would be the e-coli bacteria
that I mentioned a minute ago.
00:02:37.000 --> 00:02:39.330
Each bacterium is a single cell
00:02:39.330 --> 00:02:42.847
that's responsible for taking
in nutrients, reproducing,
00:02:42.847 --> 00:02:45.890
and doing all the things
that it needs to stay alive.
00:02:45.890 --> 00:02:48.310
So an example of a multicellular organism
00:02:48.310 --> 00:02:51.910
would be you, me, or
most any other organism
00:02:51.910 --> 00:02:54.150
that you can see with the naked eye.
00:02:54.150 --> 00:02:56.220
And the cells of multicellular organisms
00:02:56.220 --> 00:03:00.000
are often specialized to
carry out specific functions.
00:03:00.000 --> 00:03:01.090
So for example,
00:03:01.090 --> 00:03:04.080
some cells help the
organism absorb nutrients,
00:03:04.080 --> 00:03:06.270
while others transmit information,
00:03:06.270 --> 00:03:10.050
or defend against bacteria and viruses.
00:03:10.050 --> 00:03:11.510
So going back to our comparison
00:03:11.510 --> 00:03:13.490
between building blocks and cells,
00:03:13.490 --> 00:03:15.990
specialized cells are like
different building blocks
00:03:15.990 --> 00:03:19.630
of different sizes, shapes, and colors.
00:03:19.630 --> 00:03:20.780
And these different blocks
00:03:20.780 --> 00:03:22.710
can come together to
build something larger,
00:03:22.710 --> 00:03:24.400
like this airplane here.
00:03:24.400 --> 00:03:26.730
Similarly, cells with different structures
00:03:26.730 --> 00:03:29.740
and functions come together
to make something larger,
00:03:29.740 --> 00:03:33.063
an organism like this
adorable kitten right here.
00:03:34.150 --> 00:03:35.970
So to sum up cells and organisms,
00:03:35.970 --> 00:03:39.530
today, we learned that cells
are the smallest unit of life.
00:03:39.530 --> 00:03:42.770
We talked about how all
organisms are made up of cells,
00:03:42.770 --> 00:03:46.580
and that organisms can be
unicellular or multicellular.
00:03:46.580 --> 00:03:48.750
So I hope that now you
have a good understanding
00:03:48.750 --> 00:03:50.160
of cells and organisms,
00:03:50.160 --> 00:03:52.900
as well as a new perspective
about building blocks,
00:03:52.900 --> 00:03:56.323
not the toys, but the cells
that make up life itself.
|
Subtracting with place value blocks (regrouping) | https://www.youtube.com/watch?v=F63kWrYg6fY | vtt | https://www.youtube.com/api/timedtext?v=F63kWrYg6fY&ei=xFWUZfyCFaeEmLAP_rGFgAM&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245300&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=6DC3F9CFE80F6724C9107591F82DA2B9BC9A306C.8729311BEA9CE60BD4524934A34258B0BB433C96&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.500 --> 00:00:01.860
- [Instructor] What we
want to do in this video
00:00:01.860 --> 00:00:06.760
is figure out what 438 minus 272 is
00:00:06.760 --> 00:00:08.930
and to help us think about that
00:00:08.930 --> 00:00:13.550
we have these place value
blocks right over here.
00:00:13.550 --> 00:00:15.630
So you can see 438.
00:00:15.630 --> 00:00:20.170
We have four hundreds, 100, 200, 300, 400.
00:00:20.170 --> 00:00:23.950
We have three tens, one, two, three
00:00:23.950 --> 00:00:25.750
and then we have eight ones.
00:00:25.750 --> 00:00:28.370
You can count those eight
ones right over there.
00:00:28.370 --> 00:00:30.710
From that, we're going to
take away two hundreds,
00:00:30.710 --> 00:00:32.810
so that's 200 right over there,
00:00:32.810 --> 00:00:37.310
seven tens or 70 right
over here, and two ones.
00:00:37.310 --> 00:00:38.290
So pause this video
00:00:38.290 --> 00:00:41.040
and see if you can figure
out what this is going to be.
00:00:41.950 --> 00:00:42.783
All right.
00:00:42.783 --> 00:00:45.400
Now let's work through this together.
00:00:45.400 --> 00:00:48.730
So first of all, we could
start in the ones place
00:00:48.730 --> 00:00:51.430
and we can see we have eight ones
00:00:51.430 --> 00:00:53.070
and then we're gonna take away two ones.
00:00:53.070 --> 00:00:55.250
So that's pretty straight forward.
00:00:55.250 --> 00:00:59.863
We're just going to be left
with six ones right over here.
00:01:00.740 --> 00:01:02.860
Now let's go to the tens place.
00:01:02.860 --> 00:01:04.770
Now the tens place is interesting.
00:01:04.770 --> 00:01:06.270
We have three tens here
00:01:06.270 --> 00:01:08.040
and we're trying to take away from that
00:01:08.040 --> 00:01:12.140
one, two, three, four,
five, six, seven tens.
00:01:12.140 --> 00:01:15.760
So how do you take seven
tens from three tens?
00:01:15.760 --> 00:01:20.760
Well, luckily we can regroup
from the hundreds place.
00:01:20.890 --> 00:01:25.890
What if we were to take
this piece right over here
00:01:26.280 --> 00:01:28.490
from the hundreds to the tens place
00:01:28.490 --> 00:01:31.750
and now this is going to be
the equivalent of 10 tens.
00:01:31.750 --> 00:01:34.250
So let me represent it that way.
00:01:34.250 --> 00:01:36.470
Once again, I took a hundreds.
00:01:36.470 --> 00:01:38.210
That's the same thing as one, two, three
00:01:38.210 --> 00:01:42.380
four, five, six, seven,
eight, nine, 10 tens.
00:01:42.380 --> 00:01:43.340
Well, this is useful now,
00:01:43.340 --> 00:01:45.960
because now I have 10 plus three tens,
00:01:45.960 --> 00:01:47.820
or you could say I have 13 tens
00:01:47.820 --> 00:01:50.520
and now I can take away
seven tens from that.
00:01:50.520 --> 00:01:51.920
So let's do that.
00:01:51.920 --> 00:01:56.920
Let's take away one, two,
three, four, five, six, seven
00:02:00.120 --> 00:02:05.060
and what we are left with
is six tens right over here.
00:02:05.060 --> 00:02:08.990
So now I have six tens left, six ones left
00:02:08.990 --> 00:02:11.100
and in the hundreds,
I have three hundreds.
00:02:11.100 --> 00:02:12.270
I'm gonna take away two of them.
00:02:12.270 --> 00:02:15.330
So I'm gonna take away 100 and 200.
00:02:15.330 --> 00:02:17.550
So I'm left with just 100 there.
00:02:17.550 --> 00:02:21.710
So I'm left with one hundred,
six tens and six ones.
00:02:21.710 --> 00:02:26.297
So this is one hundred, six
tens and six ones, or 166.
|
Using probability to make fair decisions | https://www.youtube.com/watch?v=Z_5f3kys52o | vtt | https://www.youtube.com/api/timedtext?v=Z_5f3kys52o&ei=xFWUZdj4E6-4vdIPhp6OqAM&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245300&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=B5D12EFF527779934E01DA94C7D8AE4AF8ECEA2D.A0A132CA7EF2C7A1DABE1C66329A53F25627987E&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.260 --> 00:00:01.970
- [Instructor] We're told
that Roberto and Jocelyn
00:00:01.970 --> 00:00:05.420
decide to roll a pair
of fair six-sided dice
00:00:05.420 --> 00:00:08.107
to determine who has to
dust their apartment.
00:00:08.107 --> 00:00:11.730
If the sum is seven,
then Roberto will dust.
00:00:11.730 --> 00:00:15.840
If the sum is 10 or 11,
then Jocelyn will dust.
00:00:15.840 --> 00:00:19.860
If the sum is anything
else, they'll roll again.
00:00:19.860 --> 00:00:22.589
Is this a fair way to decide who dusts?
00:00:22.589 --> 00:00:24.730
Why or why not?
00:00:24.730 --> 00:00:25.950
So pause this video and see
00:00:25.950 --> 00:00:28.989
if you can figure this out
before we do it together.
00:00:28.989 --> 00:00:31.130
All right, now let's do this together.
00:00:31.130 --> 00:00:33.050
So what I wanna do is
make a table that shows
00:00:33.050 --> 00:00:35.600
all of the different scenarios for rolling
00:00:37.559 --> 00:00:40.610
two fair six-sided dice.
00:00:40.610 --> 00:00:44.800
So let me make columns for roll one.
00:00:44.800 --> 00:00:48.140
So that is when you get a one.
00:00:48.140 --> 00:00:49.520
This is when you get a two.
00:00:49.520 --> 00:00:51.287
This is when you get a three.
00:00:51.287 --> 00:00:53.680
This is when you get a four.
00:00:53.680 --> 00:00:55.520
This is when you get a five.
00:00:55.520 --> 00:00:58.880
And then, this is when you get a six.
00:00:58.880 --> 00:01:02.290
And then here, let's do the other die.
00:01:02.290 --> 00:01:04.350
So this is when you get a one.
00:01:04.350 --> 00:01:06.820
This is when you get a two.
00:01:06.820 --> 00:01:08.790
This is when you get a three.
00:01:08.790 --> 00:01:10.766
This is when you get a four.
00:01:10.766 --> 00:01:13.150
This is when you get a five.
00:01:13.150 --> 00:01:15.680
And then, this is when you get a six.
00:01:15.680 --> 00:01:16.830
So one way to think about it
00:01:16.830 --> 00:01:21.370
is this is roll one
00:01:21.370 --> 00:01:22.790
or let me write it this way,
00:01:22.790 --> 00:01:25.400
d1 and d2.
00:01:25.400 --> 00:01:28.753
This could be a one, a two,
a three, a five or a six.
00:01:29.812 --> 00:01:33.700
And this could be a one,
a two, a three, a four,
00:01:33.700 --> 00:01:36.070
a five or a six.
00:01:36.070 --> 00:01:40.210
Now what we could do is
fill in these 36 squares
00:01:40.210 --> 00:01:41.530
to figure out what the sum is.
00:01:41.530 --> 00:01:42.380
Actually, let me just do that
00:01:42.380 --> 00:01:43.600
and I'll try to do it really fast,
00:01:43.600 --> 00:01:44.670
one + one is two.
00:01:44.670 --> 00:01:49.150
So it's three, four, five, six, seven.
00:01:49.150 --> 00:01:53.070
This is three, four,
five, six, seven, eight.
00:01:53.070 --> 00:01:57.430
This is four, five,
six, seven, eight, nine.
00:01:57.430 --> 00:02:02.030
This is five, six, seven, eight, nine, 10.
00:02:02.030 --> 00:02:06.970
This is six, seven, eight, nine, 10, 11.
00:02:06.970 --> 00:02:07.890
Last but not least,
00:02:07.890 --> 00:02:11.950
seven, eight, nine, 10, 11 and 12,
00:02:11.950 --> 00:02:13.721
took a little less time than I suspected.
00:02:13.721 --> 00:02:15.610
All right, let's think
about this scenario.
00:02:15.610 --> 00:02:18.740
If the sum is seven,
then Roberto will dust.
00:02:18.740 --> 00:02:20.750
So where is the sum seven?
00:02:20.750 --> 00:02:24.680
So we have that ones, twice, three times,
00:02:24.680 --> 00:02:27.250
four, five, six.
00:02:27.250 --> 00:02:30.990
So six out of, so six of these outcomes
00:02:30.990 --> 00:02:32.560
result in a sum of seven.
00:02:32.560 --> 00:02:36.290
And how many possible equally
likely outcomes are there?
00:02:36.290 --> 00:02:38.470
Well, there are six times six
00:02:38.470 --> 00:02:41.630
equally possible outcomes or 36.
00:02:41.630 --> 00:02:43.108
So six out of the 36
00:02:43.108 --> 00:02:44.730
or this is another way of saying
00:02:44.730 --> 00:02:48.920
there's a 1/6 probability
that Roberto will dust.
00:02:48.920 --> 00:02:51.590
And then, let's think
about the 10s or 11s.
00:02:51.590 --> 00:02:53.480
If the sum is 10 or 11,
00:02:53.480 --> 00:02:56.023
then Jocelyn will dust.
00:02:56.860 --> 00:02:58.530
So 10 or 11,
00:02:58.530 --> 00:03:01.180
so we have one, two,
00:03:01.180 --> 00:03:05.100
three, four, five.
00:03:05.100 --> 00:03:10.100
So this is only happening
five out of the 36 times.
00:03:10.120 --> 00:03:11.610
So in any given roll,
00:03:11.610 --> 00:03:14.230
it's a higher probability that Roberto
00:03:14.230 --> 00:03:16.810
will dust than Jocelyn will dust.
00:03:16.810 --> 00:03:18.470
And of course, if neither of these happen,
00:03:18.470 --> 00:03:19.740
they are going to roll again.
00:03:19.740 --> 00:03:20.920
But on that second roll,
00:03:20.920 --> 00:03:23.630
there's a higher probability
that Roberto will dust
00:03:23.630 --> 00:03:24.860
than Jocelyn will dust.
00:03:24.860 --> 00:03:27.280
So in general, this is not fair.
00:03:27.280 --> 00:03:30.720
There's a higher probability
that Roberto dusts.
00:03:30.720 --> 00:03:32.933
So this is our choice.
|
3 Minute Breather for Teachers | https://www.youtube.com/watch?v=X4bl_VTyMa0 | vtt | https://www.youtube.com/api/timedtext?v=X4bl_VTyMa0&ei=xFWUZYK_K5vVxN8PxJG_8AM&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245300&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=0426BB9B7444D10B3AD66530865378CDDAB2A452.DA26C72A0603282807092E6AD9096354F7607518&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.330 --> 00:00:04.553
- Welcome, teachers, for
this short guided meditation.
00:00:06.170 --> 00:00:07.880
Remind yourself that meditation,
00:00:07.880 --> 00:00:10.240
there's no right way to do it.
00:00:10.240 --> 00:00:14.900
It's just an opportunity
to still your mind,
00:00:14.900 --> 00:00:19.430
take a break from all the
thoughts that you normally have,
00:00:19.430 --> 00:00:22.580
the planning, the to-do's of the future,
00:00:22.580 --> 00:00:23.793
thoughts of the past,
00:00:25.090 --> 00:00:28.803
and just be in the moment, and be still.
00:00:30.720 --> 00:00:33.930
So let's start by taking a few deep
00:00:33.930 --> 00:00:37.323
and controlled breaths
together in through our nose.
00:00:40.110 --> 00:00:40.943
Hold.
00:00:46.650 --> 00:00:48.473
And out through our mouths.
00:00:56.190 --> 00:00:57.493
In through our nose.
00:01:00.240 --> 00:01:01.073
Hold.
00:01:09.380 --> 00:01:10.980
And then out through your mouth.
00:01:16.590 --> 00:01:19.690
Now I encourage you to continue to breathe
00:01:19.690 --> 00:01:23.473
in a deep and controlled way,
00:01:24.460 --> 00:01:28.233
but as you do so, try to
put a smile on your face.
00:01:29.440 --> 00:01:31.373
It might feel a little artificial,
00:01:32.830 --> 00:01:35.090
but I promise it'll actually feel good.
00:01:35.090 --> 00:01:38.470
Even if your mood might not
have made you want to smile,
00:01:38.470 --> 00:01:41.370
just put a big cheesy smile on your face
00:01:41.370 --> 00:01:42.963
as you continue to breathe in.
00:01:48.240 --> 00:01:49.073
And out.
00:01:58.150 --> 00:02:00.250
So as you go through the rest of your day,
00:02:01.310 --> 00:02:03.833
encourage you to take breaks like this,
00:02:05.370 --> 00:02:08.373
moment of pause, moment of stillness,
00:02:09.760 --> 00:02:12.233
approached with a sense of acceptance,
00:02:13.520 --> 00:02:18.253
a sense of curiosity,
even a sense of humor.
00:02:21.470 --> 00:02:23.643
And remind yourself that as a teacher,
00:02:24.900 --> 00:02:27.313
you give so much of yourself to others,
00:02:28.940 --> 00:02:30.940
but you need to have a source of energy.
00:02:32.560 --> 00:02:34.600
And so for their sake,
00:02:34.600 --> 00:02:36.900
it's important that you
take care of yourself.
00:02:39.470 --> 00:02:42.143
It's important that you
give your mind a break,
00:02:43.917 --> 00:02:45.490
and be in the moment,
00:02:45.490 --> 00:02:48.953
in a moment of stillness and acceptance.
00:02:51.610 --> 00:02:52.770
And maybe in a little way,
00:02:52.770 --> 00:02:56.870
resolve and refresh
everything that's going on
00:02:56.870 --> 00:03:01.523
to tackle the day, the
weeks, the months ahead.
00:03:05.148 --> 00:03:06.065
Thank you.
|
Inequalities word problems | https://www.youtube.com/watch?v=VEIf5TfceAw | vtt | https://www.youtube.com/api/timedtext?v=VEIf5TfceAw&ei=xFWUZZ2WFYmFp-oP1pCvyAw&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245300&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=207CA3D52852C6BAA42C69346CE3FE4806187633.3F049E8D4CB06EE999DD12A44191B904992C89D9&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:03.340 --> 00:00:04.310
- [Instructor] We're told that Eric
00:00:04.310 --> 00:00:05.800
is shorter than Priti.
00:00:05.800 --> 00:00:09.470
Priti is 158 centimeters tall.
00:00:09.470 --> 00:00:12.160
Write an inequality that
compares Eric's height
00:00:12.160 --> 00:00:15.640
in centimeters, E, to Priti's height.
00:00:15.640 --> 00:00:18.340
Pause this video and
see if you can do that.
00:00:18.340 --> 00:00:20.620
Alright, so we have Eric's height,
00:00:20.620 --> 00:00:23.780
which we are using the
variable capital E for,
00:00:23.780 --> 00:00:24.860
And how does it compare?
00:00:24.860 --> 00:00:27.710
It says Eric is shorter than Priti.
00:00:27.710 --> 00:00:31.640
So Eric's height is going to be less than
00:00:31.640 --> 00:00:36.640
whatever Priti's height is,
which is 158 centimeters.
00:00:37.570 --> 00:00:39.320
You could think about
it on a number line too.
00:00:39.320 --> 00:00:41.680
If I were to draw a number line like this,
00:00:41.680 --> 00:00:46.680
and this is 158
centimeters, Priti's height,
00:00:46.780 --> 00:00:51.350
Eric's is gonna be less than
that 'cause he is shorter.
00:00:51.350 --> 00:00:55.200
So it would be all of the
values that are to the left of,
00:00:55.200 --> 00:00:56.860
let me do this in another color,
00:00:56.860 --> 00:00:59.330
that are less than that.
00:00:59.330 --> 00:01:00.790
Just like that.
00:01:00.790 --> 00:01:02.763
Let's do another example.
00:01:05.310 --> 00:01:09.030
Here we are told that Sydney wears skirts
00:01:09.030 --> 00:01:14.030
when the temperature is warmer
than 25 degrees Celsius.
00:01:14.740 --> 00:01:17.800
Write an inequality that describes T,
00:01:17.800 --> 00:01:21.890
the temperatures at which
Sydney wears skirts.
00:01:21.890 --> 00:01:23.180
So again, pause this video and see
00:01:23.180 --> 00:01:24.943
if you can have a go at that.
00:01:26.440 --> 00:01:29.810
Alright. So when does Sydney wear skirts?
00:01:29.810 --> 00:01:34.100
When the temperature is warmer
than 25 degrees Celsius.
00:01:34.100 --> 00:01:36.680
Now, warmer means that
the temperature is higher
00:01:36.680 --> 00:01:38.550
than 25 degrees Celsius,
00:01:38.550 --> 00:01:43.350
or that the temperature is
greater than 25 degrees Celsius.
00:01:43.350 --> 00:01:46.630
And we're using capital
T to denote temperature.
00:01:46.630 --> 00:01:51.260
So we would say capital
T, this needs to be higher
00:01:51.260 --> 00:01:56.260
than 25 degrees, or greater
than 25 degrees Celsius.
00:01:56.890 --> 00:02:00.460
So T is greater than 25.
00:02:00.460 --> 00:02:03.580
Let's do one last example here.
00:02:03.580 --> 00:02:08.580
So here we are told that Lola
and Hayley are running a race.
00:02:10.350 --> 00:02:13.610
Lola finishes the race in 53 seconds.
00:02:13.610 --> 00:02:16.950
Hayley finishes after Lola.
00:02:16.950 --> 00:02:19.500
Write an inequality that represents H,
00:02:19.500 --> 00:02:21.970
Hayley's finish time in seconds.
00:02:21.970 --> 00:02:25.360
Pause the video and see if
you can think about this.
00:02:25.360 --> 00:02:28.110
Alright, so how does
Hayley compare to Lola?
00:02:28.110 --> 00:02:30.800
Hayley finishes after Lola.
00:02:30.800 --> 00:02:33.070
So what does that mean
about Hayley's time?
00:02:33.070 --> 00:02:36.470
Well, that means that Hayley
is going to take more time
00:02:36.470 --> 00:02:38.370
than Lola to finish the race.
00:02:38.370 --> 00:02:41.530
So whatever Lola's time is, Hayley's time
00:02:41.530 --> 00:02:46.170
is going to be longer,
or more, or greater than.
00:02:46.170 --> 00:02:50.620
So Hayley's time is going to
be greater than Lola's time,
00:02:50.620 --> 00:02:52.300
which is 53 seconds,
00:02:52.300 --> 00:02:55.253
because Hayley finishes after.
|
Finding mistakes in one-step equations | https://www.youtube.com/watch?v=CUB5j3Frev0 | vtt | https://www.youtube.com/api/timedtext?v=CUB5j3Frev0&ei=xFWUZZymE720xN8PrseoyAs&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245300&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=21016C7B09E52EAB74E31E1E2FD9704D03C3E436.A4DE5EAA189E54DCCD784C8889D2A2E0158602E9&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.400 --> 00:00:01.240
- [Instructor] We're told that Lisa
00:00:01.240 --> 00:00:03.290
tried to solve an equation.
00:00:03.290 --> 00:00:07.070
See, 42 is equal to 6a, or six times a.
00:00:07.070 --> 00:00:09.360
And then we can see her steps here.
00:00:09.360 --> 00:00:12.520
And they say, where did
Lisa make her first mistake?
00:00:12.520 --> 00:00:14.850
So pause this video, and see
if you can figure that out.
00:00:14.850 --> 00:00:17.150
And it might be possible
she made no mistakes.
00:00:18.640 --> 00:00:19.910
All right.
00:00:19.910 --> 00:00:22.360
Well, we know she ends
up with seven equals six,
00:00:22.360 --> 00:00:26.200
which is sketchy, so let's
see what happened here.
00:00:26.200 --> 00:00:29.320
So right over here, it looks like,
00:00:29.320 --> 00:00:31.100
well, she did something
a little bit strange.
00:00:31.100 --> 00:00:33.510
She divided the left-hand side by six,
00:00:33.510 --> 00:00:35.990
and the right hand side by a.
00:00:35.990 --> 00:00:38.300
You don't want to divide
two sides of an equation
00:00:38.300 --> 00:00:40.090
by two different things.
00:00:40.090 --> 00:00:42.150
Then it's no longer
going to be an equation.
00:00:42.150 --> 00:00:43.767
The equality won't hold.
00:00:43.767 --> 00:00:46.710
An algebraically legitimate thing
00:00:46.710 --> 00:00:49.100
is to do the same thing to both sides,
00:00:49.100 --> 00:00:50.510
but she didn't do it here.
00:00:50.510 --> 00:00:54.320
So this is where she
made her first mistake.
00:00:54.320 --> 00:00:56.940
Let's give another example here.
00:00:56.940 --> 00:01:00.010
So here it says that Jin
tried to solve an equation.
00:01:00.010 --> 00:01:03.780
All right, x plus 4.7 is equal to 11.2.
00:01:03.780 --> 00:01:05.980
Where did Jin make his first mistake?
00:01:05.980 --> 00:01:08.730
Pause this video, and
try to figure it out.
00:01:08.730 --> 00:01:09.563
All right,
00:01:09.563 --> 00:01:11.510
so it looks like in order to isolate the x
00:01:11.510 --> 00:01:16.510
on the left-hand side, Jin is
subtracting 4.7 from the left,
00:01:16.550 --> 00:01:21.080
and then also subtracting
4.7 from the right.
00:01:21.080 --> 00:01:24.540
So that is looking good, doing
the same thing to both sides,
00:01:24.540 --> 00:01:26.920
subtracting 4.7 from both sides.
00:01:26.920 --> 00:01:29.675
And then over here on the left-hand side,
00:01:29.675 --> 00:01:31.368
these two would cancel.
00:01:31.368 --> 00:01:33.760
So you'd be left with just an x,
00:01:33.760 --> 00:01:37.123
and let's see, 11.2 minus 4.7.
00:01:38.325 --> 00:01:42.577
11.2 minus four would be 7.2,
00:01:44.650 --> 00:01:47.250
and then minus the 0.7 would be 6.5.
00:01:47.250 --> 00:01:50.870
So this is where Jin made his mistake,
00:01:50.870 --> 00:01:53.550
on the calculating part.
00:01:53.550 --> 00:01:55.900
Let's do another example,
this is a lot of fun.
00:01:56.960 --> 00:02:00.304
So here we are told that Marina
tried to solve an equation,
00:02:00.304 --> 00:02:01.580
and we need to figure out
00:02:01.580 --> 00:02:04.770
where Marina made her first mistake.
00:02:04.770 --> 00:02:09.360
All right, one-sixth is
equal to two-thirds, why?
00:02:09.360 --> 00:02:11.260
So the first step,
00:02:11.260 --> 00:02:14.680
or the first thing that
Marina did right over here
00:02:14.680 --> 00:02:18.630
is to multiply both sides of this equation
00:02:18.630 --> 00:02:21.640
by the reciprocal of two-thirds,
which is three halves.
00:02:21.640 --> 00:02:23.990
Multiplied the left-hand
side by three halves,
00:02:23.990 --> 00:02:26.520
multiplied the right-hand
side by three halves,
00:02:26.520 --> 00:02:29.660
which is a very reasonable thing to do.
00:02:29.660 --> 00:02:30.997
We're doing the same thing to both sides,
00:02:30.997 --> 00:02:33.130
multiplying by three halves.
00:02:33.130 --> 00:02:36.130
And then when we go over here, let's see,
00:02:36.130 --> 00:02:38.920
three halves times one-sixth.
00:02:38.920 --> 00:02:42.370
We could divide the numerator
and the denominator by three.
00:02:42.370 --> 00:02:44.960
So it's gonna be one over two.
00:02:44.960 --> 00:02:47.240
So that indeed is going to
be one half times one half,
00:02:47.240 --> 00:02:49.540
which is one-fourth, so that checks out.
00:02:49.540 --> 00:02:50.530
And on this side,
00:02:50.530 --> 00:02:52.290
if you multiply three
halves times two-thirds,
00:02:52.290 --> 00:02:54.660
that's going to be one,
so this checks out.
00:02:54.660 --> 00:02:57.950
So it actually looks like
Marina did everything correctly.
00:02:57.950 --> 00:03:02.950
So no mistake, no mistake for Marina.
00:03:03.300 --> 00:03:05.853
Let's do one last example.
00:03:07.380 --> 00:03:10.570
So here, Taylor is trying
to solve an equation.
00:03:10.570 --> 00:03:14.210
And so where did Taylor
first get tripped up?
00:03:14.210 --> 00:03:16.293
N minus 2.7 is equal to 6.7.
00:03:17.450 --> 00:03:20.220
In order to isolate this N over here,
00:03:20.220 --> 00:03:24.030
I would add 2.7 to both sides,
00:03:24.030 --> 00:03:26.960
but that's not what Taylor did.
00:03:26.960 --> 00:03:31.750
Taylor subtracted 2.7 from both sides.
00:03:31.750 --> 00:03:34.460
So the first place that
Taylor starts to trip up,
00:03:34.460 --> 00:03:39.000
or move in the wrong
direction is right over here.
00:03:39.000 --> 00:03:43.750
Now, what Taylor did is not
algebraically incorrect.
00:03:43.750 --> 00:03:48.750
You would end up with n
minus 5.4 is equal to four,
00:03:49.870 --> 00:03:52.290
but it's not going to help
you solve this equation.
00:03:52.290 --> 00:03:53.980
You just replaced this equation
00:03:53.980 --> 00:03:55.830
with another equivalent equation
00:03:55.830 --> 00:03:59.440
that is no simpler than the one before.
00:03:59.440 --> 00:04:00.273
And then of course,
00:04:00.273 --> 00:04:02.810
instead of getting n
minus 5.4 equals four,
00:04:02.810 --> 00:04:06.030
Taylor calculated incorrectly as well.
00:04:06.030 --> 00:04:07.890
But where they first
started to get tripped up,
00:04:07.890 --> 00:04:09.670
or at least not move
in the right direction
00:04:09.670 --> 00:04:11.113
would be right over here.
|
One-step multiplication equations: fractional coefficients | https://www.youtube.com/watch?v=vksy7e3hY8Q | vtt | https://www.youtube.com/api/timedtext?v=vksy7e3hY8Q&ei=xFWUZZG6ErCKvdIPxLSi6A0&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245300&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=9854565E579450B94ED6A3C73A0C53774EE69AE4.0D3AD3CF781A75982A2B2E358FB56773F36E6AC9&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.770 --> 00:00:02.440
- Let's say that we have the equation,
00:00:02.440 --> 00:00:06.730
two-fifths X is equal to 10.
00:00:06.730 --> 00:00:08.703
How would you go about solving that?
00:00:09.640 --> 00:00:11.230
Well, you might be thinking to yourself,
00:00:11.230 --> 00:00:12.980
it would be nice if we just had an X
00:00:12.980 --> 00:00:15.620
on the left-hand side
instead of a two-fifths X,
00:00:15.620 --> 00:00:17.820
or if the coefficient on the X were one
00:00:17.820 --> 00:00:19.120
instead of a two-fifths.
00:00:19.120 --> 00:00:21.400
And the way that we might do that,
00:00:21.400 --> 00:00:22.730
is if we were to multiply
00:00:22.730 --> 00:00:27.440
both sides of this
equation by five halves.
00:00:27.440 --> 00:00:29.490
Why five halves?
00:00:29.490 --> 00:00:30.670
Well, five halves,
00:00:30.670 --> 00:00:31.503
if you notice,
00:00:31.503 --> 00:00:33.880
when I multiply five
halves times two-fifths,
00:00:33.880 --> 00:00:35.540
it's going to get us to one.
00:00:35.540 --> 00:00:37.417
Five times two is 10,
00:00:37.417 --> 00:00:39.140
two times five is 10.
00:00:39.140 --> 00:00:41.460
So it's going to be 10 over 10 or one,
00:00:41.460 --> 00:00:44.800
or you could think about
five divided by five is one,
00:00:44.800 --> 00:00:47.220
two divided by two is one.
00:00:47.220 --> 00:00:48.670
And you might say, "Is that magical?
00:00:48.670 --> 00:00:51.100
How did you think of five halves?"
00:00:51.100 --> 00:00:53.670
Well, five halves is just
the reciprocal of two-fifths.
00:00:53.670 --> 00:00:56.420
I just swapped the numerator
and the denominator
00:00:56.420 --> 00:00:57.600
to get five halves.
00:00:57.600 --> 00:00:59.960
And then why did I multiply
it times the right-hand side?
00:00:59.960 --> 00:01:01.247
Well, anything I do to the left hand,
00:01:01.247 --> 00:01:03.640
I also want to do to the right hand.
00:01:03.640 --> 00:01:07.460
So the left-hand side
simplifies to this is all one.
00:01:07.460 --> 00:01:10.792
So it's just going to be X is equal to,
00:01:10.792 --> 00:01:14.470
or we could say one X is
equal to 10 times five halves.
00:01:14.470 --> 00:01:17.020
That's the same thing as 50 halves.
00:01:17.020 --> 00:01:19.410
I could write it this way, 50 over two,
00:01:19.410 --> 00:01:22.910
which is the same thing as 25.
00:01:22.910 --> 00:01:24.160
Let's do another example.
00:01:25.010 --> 00:01:26.410
Let's say we have the equation,
00:01:26.410 --> 00:01:28.010
14 is equal
00:01:28.010 --> 00:01:30.660
to seven-thirds B.
00:01:30.660 --> 00:01:32.533
See if you can solve this.
00:01:33.460 --> 00:01:34.600
Well, once again,
00:01:34.600 --> 00:01:36.080
it'd be nice if the coefficient
00:01:36.080 --> 00:01:38.030
on the B weren't seven-thirds,
00:01:38.030 --> 00:01:39.410
but instead were just a one.
00:01:39.410 --> 00:01:42.160
If it's just B is equal to something.
00:01:42.160 --> 00:01:43.580
Well, we know how to do that.
00:01:43.580 --> 00:01:46.330
We can multiply both
sides of this equation
00:01:46.330 --> 00:01:50.040
times the reciprocal
of the coefficient on B
00:01:50.040 --> 00:01:52.050
times the reciprocal of seven-thirds.
00:01:52.050 --> 00:01:54.210
What's the reciprocal of seven-thirds?
00:01:54.210 --> 00:01:56.060
Well, the denominator
will become the numerator.
00:01:56.060 --> 00:01:57.960
The numerator becomes a denominator.
00:01:57.960 --> 00:02:00.700
It's going to be three-sevenths.
00:02:00.700 --> 00:02:01.533
Now, of course,
00:02:01.533 --> 00:02:03.020
I can't just do it on one side.
00:02:03.020 --> 00:02:05.540
I have to do it on both sides.
00:02:05.540 --> 00:02:08.920
So on the right-hand
side of this equation,
00:02:08.920 --> 00:02:10.460
three divided by three is one,
00:02:10.460 --> 00:02:11.870
seven divided by seven is one.
00:02:11.870 --> 00:02:13.390
Those all cancel out to one.
00:02:13.390 --> 00:02:15.030
So you're just left with one B
00:02:15.030 --> 00:02:17.510
or just to B and 30,
00:02:17.510 --> 00:02:20.206
or three-sevenths times 14,
00:02:20.206 --> 00:02:23.690
you might see this as 14 over one.
00:02:23.690 --> 00:02:24.790
And you could say okay,
00:02:24.790 --> 00:02:28.801
this is going to be three
times 14 over seven times one,
00:02:28.801 --> 00:02:29.730
or you could say,
00:02:29.730 --> 00:02:33.770
hey, let's divide both a numerator
and denominator by seven.
00:02:33.770 --> 00:02:36.280
So this could be two.
And this could be one.
00:02:36.280 --> 00:02:39.893
So your left with three
times two over one times one
00:02:39.893 --> 00:02:43.200
which is just going to be equal to six.
00:02:43.200 --> 00:02:45.550
Let's do another example.
00:02:45.550 --> 00:02:47.020
Let's say
00:02:47.020 --> 00:02:48.620
that we had
00:02:48.620 --> 00:02:51.530
one sixth A
00:02:51.530 --> 00:02:54.710
is equal to two-thirds.
00:02:54.710 --> 00:02:57.363
How could we think about solving for A.
00:02:58.380 --> 00:02:59.680
Well, once again, it would be nice,
00:02:59.680 --> 00:03:03.410
if this one-sixth were to become a one
00:03:03.410 --> 00:03:05.980
and we could do that by multiplying by 6.
00:03:05.980 --> 00:03:09.150
Six-sixths is the same thing as one.
00:03:09.150 --> 00:03:11.300
And to make it clear that
this is the reciprocal,
00:03:11.300 --> 00:03:15.120
we could just write six wholes as six ones
00:03:15.120 --> 00:03:18.350
or six wholes when you multiply these,
00:03:18.350 --> 00:03:20.080
this is all going to be equal to one.
00:03:20.080 --> 00:03:23.610
So you're left with one
A on the left-hand side,
00:03:23.610 --> 00:03:25.470
but of course, you can't just
do it on the left-hand side.
00:03:25.470 --> 00:03:28.840
You have to also do it
on the right-hand side.
00:03:28.840 --> 00:03:31.540
So A is going to be equal to,
00:03:31.540 --> 00:03:35.760
over here we could say two
times six over three times one.
00:03:35.760 --> 00:03:38.560
So that would be twelve-thirds
00:03:38.560 --> 00:03:39.620
or we could say,
00:03:39.620 --> 00:03:42.060
look, six and three are
both divisible by three.
00:03:42.060 --> 00:03:43.582
So six divided by three is two,
00:03:43.582 --> 00:03:45.585
three divided by three is one,
00:03:45.585 --> 00:03:48.940
two times two is four over one times one.
00:03:48.940 --> 00:03:53.053
So it's going to be four wholes
or just four and we're done.
|
Analyzing relationships between variables using tables and equations | https://www.youtube.com/watch?v=Pf-s9zNDSCk | vtt | https://www.youtube.com/api/timedtext?v=Pf-s9zNDSCk&ei=xFWUZZKxKde2mLAPm8edoA4&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245300&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=24BEA02EEB024BDC96F7A1BD63700C57D36C1EC3.9BD03D3857D05115272F205504D50C247A107496&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.610 --> 00:00:03.850
- [Narrator] We're told Rava
is researching an electric car.
00:00:03.850 --> 00:00:07.710
She finds this graph,
which shows how much range,
00:00:07.710 --> 00:00:09.430
measured in kilometers,
00:00:09.430 --> 00:00:13.500
the car gains based on charging time.
00:00:13.500 --> 00:00:15.330
All right, and they say, first,
00:00:15.330 --> 00:00:18.410
fill in the missing
values in the table below.
00:00:18.410 --> 00:00:21.070
And if you are so
inspired, pause this video,
00:00:21.070 --> 00:00:24.070
and see if you can have
a go at that as well.
00:00:24.070 --> 00:00:25.540
All right, well they give us a few points,
00:00:25.540 --> 00:00:27.600
and I'm assuming these
are points on a line.
00:00:27.600 --> 00:00:31.790
And we can see when the
charging time is 15 minutes,
00:00:31.790 --> 00:00:33.540
the range is 180.
00:00:33.540 --> 00:00:36.430
So we could see when the
charging time is 15 minutes,
00:00:36.430 --> 00:00:38.920
the range is 180.
00:00:38.920 --> 00:00:43.030
We can see when the
charging time is 30 minutes,
00:00:43.030 --> 00:00:48.030
the range is 360 kilometers,
so I could write that there.
00:00:48.570 --> 00:00:53.570
And then we see when the
charging time is 45 minutes,
00:00:54.400 --> 00:00:59.270
the range is 540 kilometers.
00:00:59.270 --> 00:01:01.380
So that's all nice.
00:01:01.380 --> 00:01:03.390
But then they give us a
few other points here.
00:01:03.390 --> 00:01:07.200
They say what happens when
we are at T equals 10,
00:01:07.200 --> 00:01:10.940
or T equals one, which
aren't easy to pick out here?
00:01:10.940 --> 00:01:12.490
But this is where it might be useful,
00:01:12.490 --> 00:01:13.970
if we assume that this is a line,
00:01:13.970 --> 00:01:17.020
what is the relationship between these?
00:01:17.020 --> 00:01:19.910
So let's see, to go from 15 to 180,
00:01:19.910 --> 00:01:22.110
it looks like you're multiplying by 12.
00:01:22.110 --> 00:01:26.080
To go from 30 to 360, it looks
like we're multiplying by 12.
00:01:26.080 --> 00:01:28.420
To go from 45 to 540,
00:01:28.420 --> 00:01:31.260
it looks like we are multiplying by 12.
00:01:31.260 --> 00:01:34.130
So assuming K is just
going to be 12 times T,
00:01:34.130 --> 00:01:37.500
we know that when T equals one, K is 12,
00:01:37.500 --> 00:01:42.063
and when T equals 10, 10 times 12 is 120.
00:01:43.100 --> 00:01:45.530
All right, now the second part,
they say write an equation
00:01:45.530 --> 00:01:49.000
Rava can use to find out
how much charging time, T,
00:01:49.000 --> 00:01:54.000
it takes to gain any number
of kilometers in range, K.
00:01:54.460 --> 00:01:56.660
All right, well we already
established a relationship.
00:01:56.660 --> 00:02:01.660
We said that K is equal
to 12 times whatever T is.
00:02:02.640 --> 00:02:05.540
That's what we just established
in this table up here,
00:02:05.540 --> 00:02:06.870
but that's not what they want.
00:02:06.870 --> 00:02:09.500
They wanna find out how
much charging time, T,
00:02:09.500 --> 00:02:13.660
it takes to gain any number
of kilometers in range, K.
00:02:13.660 --> 00:02:17.050
So what we need to do here is solve for T.
00:02:17.050 --> 00:02:19.380
So let's divide both sides by 12
00:02:20.430 --> 00:02:23.820
to just have a T by itself
on the right-hand side.
00:02:23.820 --> 00:02:28.500
And we are going to be left
with T is equal to K over 12.
00:02:28.500 --> 00:02:31.010
T is equal to K over 12 and notice,
00:02:31.010 --> 00:02:34.070
you could put any number of
kilometers of range in here
00:02:34.070 --> 00:02:36.110
and you're essentially just
going to divide it by 12,
00:02:36.110 --> 00:02:38.110
and that will give you
how much charging time.
00:02:38.110 --> 00:02:41.130
And I guess this would assume
an infinitely large battery,
00:02:41.130 --> 00:02:42.900
which we know doesn't exist.
00:02:42.900 --> 00:02:45.380
But for the sake of this
problem, here we have it.
00:02:45.380 --> 00:02:47.883
Here is the equation Rava can use.
|
Writing equations for relationships between quantities | https://www.youtube.com/watch?v=5T9gSp2W3Oc | vtt | https://www.youtube.com/api/timedtext?v=5T9gSp2W3Oc&ei=xFWUZf7VEorNhcIPzsijyAM&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245300&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=66594A05F00AA377B5BE3C0C2AE9687DABEBC384.313AEC44DF688FC38EB40DC542A60650F1B3F650&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.250 --> 00:00:02.270
- [Narrator] We're told
Amad is going to walk
00:00:02.270 --> 00:00:06.030
20 kilometers for a charity fundraiser.
00:00:06.030 --> 00:00:07.290
In the first part of
this question, they say,
00:00:07.290 --> 00:00:10.980
write an equation that
represents how many hours, t,
00:00:10.980 --> 00:00:15.140
the walk will take if Amad
walks at a constant rate
00:00:15.140 --> 00:00:17.760
of r kilometers per hour.
00:00:17.760 --> 00:00:20.720
Pause this video and see if
you could have a go at that.
00:00:20.720 --> 00:00:23.120
All right, now let's work
through this together.
00:00:23.120 --> 00:00:25.050
So you might be familiar with the notion
00:00:25.050 --> 00:00:29.270
that distance is equal to rate times time.
00:00:29.270 --> 00:00:31.558
For example, if you were to walk at a rate
00:00:31.558 --> 00:00:35.100
of five kilometers per hour
00:00:35.100 --> 00:00:36.900
for two hours,
00:00:36.900 --> 00:00:40.180
you would say five times two,
five kilometers per hour,
00:00:40.180 --> 00:00:43.890
times two hours, would
give you 10 kilometers.
00:00:43.890 --> 00:00:45.210
Now in this situation,
00:00:45.210 --> 00:00:48.880
they've given us the number of kilometers
00:00:48.880 --> 00:00:50.610
or the distance in this situation,
00:00:50.610 --> 00:00:53.090
so in this situation d is equal to 20.
00:00:53.090 --> 00:00:55.840
So 20 is going to be equal to our rate,
00:00:55.840 --> 00:00:58.740
which we are told is going
to be r kilometers per hour,
00:00:58.740 --> 00:01:02.600
times our time, which is t hours.
00:01:02.600 --> 00:01:04.890
Now they're asking us for an equation
00:01:04.890 --> 00:01:08.330
that represents how many
hours the walk will take
00:01:08.330 --> 00:01:11.340
if Amad walks at a constant rate of r.
00:01:11.340 --> 00:01:12.750
So the way that it's phrased,
00:01:12.750 --> 00:01:15.960
it sounds like they
want us to solve for t,
00:01:15.960 --> 00:01:19.510
where t is going to be equal
to some expression here
00:01:19.510 --> 00:01:23.500
that deals with r and
probably some other things,
00:01:23.500 --> 00:01:27.690
so if we put in any r here,
then we can get the time.
00:01:27.690 --> 00:01:29.450
So if we know what the rate is,
00:01:29.450 --> 00:01:30.760
if you put that in here,
00:01:30.760 --> 00:01:32.460
because it's already solved for t,
00:01:32.460 --> 00:01:34.540
we'll be able to solve for that time.
00:01:34.540 --> 00:01:37.340
You could think of r as
the independent variable
00:01:37.340 --> 00:01:39.260
that you could try
different values out for,
00:01:39.260 --> 00:01:41.050
and that t is the dependent variable.
00:01:41.050 --> 00:01:44.100
It's the thing that we have solved for.
00:01:44.100 --> 00:01:45.080
So let's do that.
00:01:45.080 --> 00:01:49.870
Let's rewrite this expression
here by solving for t
00:01:49.870 --> 00:01:52.040
and I could do it right over here.
00:01:52.040 --> 00:01:55.080
If I have 20 is equal to rt,
00:01:55.080 --> 00:01:58.270
if I wanna solve for t, what can I do?
00:01:58.270 --> 00:02:01.033
Well, I could divide both sides by r.
00:02:01.970 --> 00:02:03.970
If I do that on the right-hand side,
00:02:03.970 --> 00:02:05.360
then I'm just left with a t here,
00:02:05.360 --> 00:02:07.620
because an r divided by r is just one.
00:02:07.620 --> 00:02:09.410
And on the left, I have 20 over r,
00:02:09.410 --> 00:02:13.900
so I have t is equal to 20 over r
00:02:13.900 --> 00:02:14.733
and we're done.
00:02:14.733 --> 00:02:17.675
This will tell us how many hours Amad
00:02:17.675 --> 00:02:20.590
will take to walk based on the rate.
00:02:20.590 --> 00:02:21.423
You give me a rate.
00:02:21.423 --> 00:02:22.620
I'm just gonna divide 20 by that
00:02:22.620 --> 00:02:24.210
and I'm going to give you t.
00:02:24.210 --> 00:02:25.720
You might say, why is this useful?
00:02:25.720 --> 00:02:28.150
Well, this is useful because
now that we have it written
00:02:28.150 --> 00:02:30.940
this way, any time
someone gives an r to you,
00:02:30.940 --> 00:02:33.103
you just take 20 divided
by that and it essentially
00:02:33.103 --> 00:02:36.320
is already gonna solve
for what your time is,
00:02:36.320 --> 00:02:40.010
how long Amad's gonna have to walk.
00:02:40.010 --> 00:02:42.610
Question two, how many
hours will the walk take
00:02:42.610 --> 00:02:44.500
if Amad walks at a constant rate
00:02:44.500 --> 00:02:46.640
of 6 kilometers per hour?
00:02:46.640 --> 00:02:48.020
Well, here is an example of that,
00:02:48.020 --> 00:02:50.030
where they are giving us the actual rate
00:02:50.030 --> 00:02:51.320
and they want the time.
00:02:51.320 --> 00:02:54.620
So we just take the 6
and replace it in for r,
00:02:54.620 --> 00:02:58.280
so we get t is equal to 20 over 6,
00:02:58.280 --> 00:03:01.710
which is 3 and 1/3 hours,
00:03:01.710 --> 00:03:04.500
which would be the same thing
as 3 hours and 20 minutes,
00:03:04.500 --> 00:03:06.360
depending on how you wanna view it.
00:03:06.360 --> 00:03:08.163
Let's do another example here.
00:03:09.550 --> 00:03:12.100
So here we're told at the end of each day,
00:03:12.100 --> 00:03:14.390
a restaurant makes soup
with whatever amount
00:03:14.390 --> 00:03:16.610
of vegetable stock is unused that day.
00:03:16.610 --> 00:03:18.630
Let me re-center this a little bit.
00:03:18.630 --> 00:03:22.950
The soup recipe calls for
400 milliliters of water
00:03:22.950 --> 00:03:27.330
for every 500 milliliters
of vegetable stock.
00:03:27.330 --> 00:03:30.810
Write an equation that
represents how much water
00:03:30.810 --> 00:03:34.400
the restaurant should use,
and we'll use the variable w,
00:03:34.400 --> 00:03:38.070
with any amount of vegetable stock, v.
00:03:38.070 --> 00:03:40.660
All right, and then we'll do
part two right after that,
00:03:40.660 --> 00:03:43.040
so let's look at this,
400 milliliters of water
00:03:43.040 --> 00:03:45.400
for every 500 milliliters
of vegetable stock.
00:03:45.400 --> 00:03:47.350
And so to get my head around this,
00:03:47.350 --> 00:03:48.970
I like just to think about,
00:03:48.970 --> 00:03:50.480
let's put a little table here,
00:03:50.480 --> 00:03:52.880
and so you could say amount of water,
00:03:52.880 --> 00:03:54.250
let me write it this way,
00:03:54.250 --> 00:03:58.720
water and vegetable stock,
00:03:58.720 --> 00:04:01.093
vegetable stock.
00:04:02.100 --> 00:04:05.120
So for every 500 milliliters
of vegetable stock,
00:04:05.120 --> 00:04:07.680
so if you had 500 milliliters
of vegetable stock,
00:04:07.680 --> 00:04:09.180
and I won't write the milliliters,
00:04:09.180 --> 00:04:11.870
then you're going to have
400 milliliters of water.
00:04:11.870 --> 00:04:15.580
If you had 1,000 here,
which is two times that,
00:04:15.580 --> 00:04:17.120
well, you're gonna have
twice as much water,
00:04:17.120 --> 00:04:19.140
which is going to be 800.
00:04:19.140 --> 00:04:22.080
And so you can see this
relationship that's forming.
00:04:22.080 --> 00:04:24.580
No matter what the vegetable stock is,
00:04:24.580 --> 00:04:28.360
if you essentially take 4/5 of that,
00:04:28.360 --> 00:04:29.910
that is the amount of water.
00:04:29.910 --> 00:04:32.350
You take 4/5, that is the amount of water.
00:04:32.350 --> 00:04:35.360
So if you had only 5
milliliters of vegetable stock,
00:04:35.360 --> 00:04:39.150
you take 4/5, you get the amount of water.
00:04:39.150 --> 00:04:42.610
So another way to think
about it is the water
00:04:42.610 --> 00:04:44.560
that you need to use is going to be 4/5
00:04:45.680 --> 00:04:48.570
of the amount of vegetable stock
00:04:48.570 --> 00:04:50.690
that you are going to be using,
00:04:50.690 --> 00:04:53.870
and so actually we just did part one.
00:04:53.870 --> 00:04:56.090
We wrote an equation that
represents how much water
00:04:56.090 --> 00:04:59.280
the restaurant should use with
any amount of vegetable stock
00:04:59.280 --> 00:05:00.650
and the way that they phrased it,
00:05:00.650 --> 00:05:05.310
we're solving for w given
some v that you might have.
00:05:05.310 --> 00:05:07.330
And since we're solving for w here,
00:05:07.330 --> 00:05:09.450
we would consider w the dependent variable
00:05:09.450 --> 00:05:10.680
and v as the independent variable.
00:05:10.680 --> 00:05:12.880
You can give me different vs
00:05:12.880 --> 00:05:15.730
and then I can put that into
this little equation here,
00:05:15.730 --> 00:05:17.850
and I can solve for the w,
00:05:17.850 --> 00:05:19.890
so we've done the first part.
00:05:19.890 --> 00:05:23.230
If there are 800 milliliters
of unused vegetable stock,
00:05:23.230 --> 00:05:27.160
how much water should the
restaurant use to make soup?
00:05:27.160 --> 00:05:29.720
Well, we can just take this 800
00:05:29.720 --> 00:05:32.740
and substitute it in for
v to figure that out.
00:05:32.740 --> 00:05:34.770
In this situation, the
amount of water to use
00:05:34.770 --> 00:05:39.770
is 4/5 times 800,
00:05:40.020 --> 00:05:44.280
and that's going to be,
let's see, 800 divided by 5,
00:05:44.280 --> 00:05:49.280
100 divided by 5 is 20 and so,
00:05:49.290 --> 00:05:50.330
and then you're gonna have 8 of those,
00:05:50.330 --> 00:05:54.550
so it's 160, so this was 160 times 4
00:05:54.550 --> 00:05:58.560
is equal to 640 milliliters,
00:05:58.560 --> 00:06:00.203
and we are done.
|
Dependent & independent variables | https://www.youtube.com/watch?v=SGC_d7O7_Eg | vtt | https://www.youtube.com/api/timedtext?v=SGC_d7O7_Eg&ei=ylWUZfvEKuWavdIPzYy8yAI&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245306&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=911804F44A9860A6A2D97113129DA58231EF512E.E805B40BDBA21DF06849301819CB4F1C4D5A1079&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.350 --> 00:00:03.280
- [Teacher] Let's say that
you love to eat apples,
00:00:03.280 --> 00:00:06.360
and you are going to buy a apples,
00:00:06.360 --> 00:00:08.250
so a is the number of apples,
00:00:08.250 --> 00:00:11.100
number of apples,
00:00:11.100 --> 00:00:12.410
but you also have a budget,
00:00:12.410 --> 00:00:13.880
so you have to care about costs,
00:00:13.880 --> 00:00:17.990
so let's say C is equal to the total cost,
00:00:17.990 --> 00:00:21.530
and let's say that the
price of an apple is $2,
00:00:21.530 --> 00:00:24.483
so $2 per apple.
00:00:25.530 --> 00:00:28.950
There's several ways that we
can express the relationship
00:00:28.950 --> 00:00:31.840
between the total cost
and the number of apples.
00:00:31.840 --> 00:00:34.930
One way is if we solve for the total cost,
00:00:34.930 --> 00:00:38.400
and we say, okay, the total
cost is gonna be $2 per apple
00:00:38.400 --> 00:00:40.250
times the number of apples,
00:00:40.250 --> 00:00:41.403
so it's going to be 2a.
00:00:43.210 --> 00:00:46.270
Another way that we could rewrite this
00:00:46.270 --> 00:00:49.440
if we were to divide both
sides of this by two,
00:00:49.440 --> 00:00:52.730
we would get that the number of apples
00:00:52.730 --> 00:00:57.730
is equal to cost over two.
00:00:57.900 --> 00:01:00.700
These are equivalent
expressions I should say
00:01:00.700 --> 00:01:02.470
these are equivalent equations,
00:01:02.470 --> 00:01:04.310
but the way they've been written,
00:01:04.310 --> 00:01:06.770
make it useful for different scenarios.
00:01:06.770 --> 00:01:09.360
For example, on the left-hand side here,
00:01:09.360 --> 00:01:11.760
it's really easy to try out different As
00:01:11.760 --> 00:01:14.680
and then think about how
that will affect the cost,
00:01:14.680 --> 00:01:16.790
and so when it's written like this,
00:01:16.790 --> 00:01:18.030
we would call the variable
00:01:18.030 --> 00:01:19.930
that it's easy to try
out different values,
00:01:19.930 --> 00:01:22.880
we would call that the
independent variable,
00:01:22.880 --> 00:01:25.580
independent variable,
00:01:25.580 --> 00:01:28.870
and then the one that we
are essentially solving for
00:01:28.870 --> 00:01:30.420
that we then spit out a value
00:01:30.420 --> 00:01:32.780
after we compute using
the independent variable,
00:01:32.780 --> 00:01:34.860
you call that the dependent variable.
00:01:34.860 --> 00:01:36.280
You could view it as,
00:01:36.280 --> 00:01:37.960
look in this situation,
00:01:37.960 --> 00:01:40.970
the cost is dependent
on the number of apples
00:01:40.970 --> 00:01:42.580
you choose to eat.
00:01:42.580 --> 00:01:44.180
Now, when we wrote it over here,
00:01:44.180 --> 00:01:45.380
this looks a little bit different.
00:01:45.380 --> 00:01:48.900
Now the number of apples is solved for,
00:01:48.900 --> 00:01:52.890
and we compute how many
apples based on the cost,
00:01:52.890 --> 00:01:55.660
so this would be a scenario
where you have a budget
00:01:55.660 --> 00:01:57.310
and you tell me what the budget is
00:01:57.310 --> 00:01:59.350
and I could tell you the number of apples.
00:01:59.350 --> 00:02:00.640
So in this situation,
00:02:00.640 --> 00:02:02.660
C is the independent variable,
00:02:02.660 --> 00:02:04.740
and since we have solved for a,
00:02:04.740 --> 00:02:07.170
a is the dependent variable.
00:02:07.170 --> 00:02:09.700
This is useful if I give
you a number of apples
00:02:09.700 --> 00:02:11.200
and you want to know the total cost,
00:02:11.200 --> 00:02:14.000
and this is useful if
you have a certain cost
00:02:14.000 --> 00:02:17.993
and then you want to find
out the number of apples.
|
Writing expressions with parentheses | https://www.youtube.com/watch?v=cFNbX-2R78M | vtt | https://www.youtube.com/api/timedtext?v=cFNbX-2R78M&ei=ylWUZcmrKcmQvdIP9bO7oAQ&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245306&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=A6653D22144B5D4FF48E41C282CA125334F37AC2.3C32FD133099017EC1D842A225C2A183486DF49E&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.150 --> 00:00:01.470
- [Narrator] We have
two different statements
00:00:01.470 --> 00:00:02.303
written in English
00:00:02.303 --> 00:00:04.800
that I would like you to pause this video
00:00:04.800 --> 00:00:07.373
and try to write as an
algebraic expression.
00:00:08.230 --> 00:00:10.650
All right, now let's
work on this first one.
00:00:10.650 --> 00:00:12.374
So you might be tempted to
say, all right, I have five.
00:00:12.374 --> 00:00:14.300
So let me just write a five,
00:00:14.300 --> 00:00:15.960
times and I'll write a dot
00:00:15.960 --> 00:00:17.420
because when we're dealing with algebra,
00:00:17.420 --> 00:00:19.970
if you write a traditional
multiplication sign,
00:00:19.970 --> 00:00:21.630
it can get confused with an X.
00:00:21.630 --> 00:00:23.120
So five times
00:00:23.120 --> 00:00:24.730
the difference of X and two.
00:00:24.730 --> 00:00:25.980
The difference of X and two,
00:00:25.980 --> 00:00:30.050
we could write as X minus two,
00:00:30.050 --> 00:00:32.460
but this expression has a problem
00:00:32.460 --> 00:00:33.990
because whoever's interpreting it,
00:00:33.990 --> 00:00:35.730
if they're following order of operations,
00:00:35.730 --> 00:00:36.920
which they should,
00:00:36.920 --> 00:00:38.510
that would mean that they would multiply
00:00:38.510 --> 00:00:39.970
the five and the X first
00:00:39.970 --> 00:00:41.600
and then subtract two.
00:00:41.600 --> 00:00:43.390
But that's not what's
going on in the sentence.
00:00:43.390 --> 00:00:45.030
It's five times,
00:00:45.030 --> 00:00:47.290
not X, but the difference of X and two.
00:00:47.290 --> 00:00:48.950
So what you need to do is
00:00:48.950 --> 00:00:50.590
put parentheses here
00:00:50.590 --> 00:00:52.240
to make sure that you take the difference
00:00:52.240 --> 00:00:53.730
of X and two first,
00:00:53.730 --> 00:00:56.480
and then multiply that by five.
00:00:56.480 --> 00:00:58.100
Now, with that in mind,
00:00:58.100 --> 00:01:00.440
let's tackle this example right over here,
00:01:00.440 --> 00:01:02.603
10 times the sum of Y and three.
00:01:03.460 --> 00:01:04.293
Well, once again,
00:01:04.293 --> 00:01:07.000
if you just wrote 10 times
00:01:07.000 --> 00:01:08.030
the sum
00:01:08.030 --> 00:01:09.690
of Y and three,
00:01:09.690 --> 00:01:11.520
you'll run into the same problem.
00:01:11.520 --> 00:01:13.070
someone would interpret this as,
00:01:13.070 --> 00:01:14.879
hey, maybe I should
multiply 10 and Y first,
00:01:14.879 --> 00:01:17.800
because that's what order of
operations would tell me to do,
00:01:17.800 --> 00:01:18.750
but that's not what we want.
00:01:18.750 --> 00:01:20.780
We want 10 times, not just Y,
00:01:20.780 --> 00:01:23.050
but the sum of Y and three.
00:01:23.050 --> 00:01:24.590
So that's where the parentheses
00:01:24.590 --> 00:01:26.260
are really important to make sure
00:01:26.260 --> 00:01:28.930
that we take the sum of Y and three first
00:01:28.930 --> 00:01:31.263
and then multiply that by 10.
|
Writing algebraic subtraction expressions | https://www.youtube.com/watch?v=eFXcsXnKkjw | vtt | https://www.youtube.com/api/timedtext?v=eFXcsXnKkjw&ei=ylWUZfvGMquMp-oPkYWjwAE&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245306&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=2BDD80AEF7630880E5445DDCB8C5B2A29413BCE7.B62100A6468F0895F92FD2B47962EC176AB0869E&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.120 --> 00:00:01.550
- [Instructor] We have
different statements here
00:00:01.550 --> 00:00:05.240
that can each be expressed
as an algebraic expression,
00:00:05.240 --> 00:00:07.110
and as you might have guessed,
00:00:07.110 --> 00:00:09.750
I would love you to pause this video
00:00:09.750 --> 00:00:12.480
and try to write each of these statements
00:00:12.480 --> 00:00:15.273
as an algebraic expression
before we do it together.
00:00:16.700 --> 00:00:19.360
All right, now let's work on it together.
00:00:19.360 --> 00:00:24.360
So this first statement,
we have two less than x.
00:00:24.410 --> 00:00:27.390
So my brain thinks, all
right, let me start with x,
00:00:27.390 --> 00:00:29.340
and how am I going to
get two less than that?
00:00:29.340 --> 00:00:31.920
Well, I'm going to subtract two.
00:00:31.920 --> 00:00:33.630
And this is an interesting example
00:00:33.630 --> 00:00:35.580
because you see the order that we see it
00:00:35.580 --> 00:00:37.840
in the sentence is not the order
00:00:37.840 --> 00:00:39.450
that we would necessarily write it
00:00:39.450 --> 00:00:41.300
in the expression right over here.
00:00:41.300 --> 00:00:44.380
Very important to think
about, what is going on here?
00:00:44.380 --> 00:00:47.290
What is being described?
00:00:47.290 --> 00:00:51.340
Now, this next statement,
y fewer than three.
00:00:51.340 --> 00:00:54.760
Well, in my mind, I'm
going to start with three
00:00:54.760 --> 00:00:57.060
and I'm going to be y fewer than that.
00:00:57.060 --> 00:00:58.760
So I'm gonna start with three
00:00:58.760 --> 00:01:02.480
and then I'm going to
be y fewer than that.
00:01:02.480 --> 00:01:04.420
Now, these first two
statements are similar
00:01:04.420 --> 00:01:06.760
in that you have something
less than something else
00:01:06.760 --> 00:01:08.930
or something fewer than something else.
00:01:08.930 --> 00:01:11.963
They just swapped the
number and the variable.
00:01:12.850 --> 00:01:17.850
Now, this third statement,
x decreased by five.
00:01:18.580 --> 00:01:20.710
So my mind is thinking,
what am I starting with?
00:01:20.710 --> 00:01:24.810
I'm starting with an x and
I'm decreasing it by five.
00:01:24.810 --> 00:01:26.670
So I can do that as minus five,
00:01:26.670 --> 00:01:28.793
or I'm gonna take five away from it.
|
Evaluating expressions like 5x² & ⅓(6)ˣ | https://www.youtube.com/watch?v=ccyZpjKvJV8 | vtt | https://www.youtube.com/api/timedtext?v=ccyZpjKvJV8&ei=ylWUZfD0JI6qp-oP0f-XOA&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245306&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=8C4EC054F57193484226C36E1721F325C67B849A.67CEFF7982E44E36ACDF5193EEE22AB3574E9569&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.120 --> 00:00:02.050
- [Instructor] What I
want you to do is evaluate
00:00:02.050 --> 00:00:04.340
the expression 5x squared
00:00:04.340 --> 00:00:07.150
when x is equal to three.
00:00:07.150 --> 00:00:09.100
Pause this video and have a go at that.
00:00:10.530 --> 00:00:12.220
All right, well, we just have to think
00:00:12.220 --> 00:00:14.050
about every place we see an x,
00:00:14.050 --> 00:00:16.000
we'll now replace it with a three.
00:00:16.000 --> 00:00:18.500
So this is going to be
equivalent to five times,
00:00:18.500 --> 00:00:19.780
instead of x squared,
00:00:19.780 --> 00:00:23.800
it's going to be five times three squared.
00:00:23.800 --> 00:00:25.500
And we know from order of operations,
00:00:25.500 --> 00:00:26.980
we do the exponents first.
00:00:26.980 --> 00:00:28.520
That's why I actually put a parentheses
00:00:28.520 --> 00:00:31.060
around the three squared
to just make that clear.
00:00:31.060 --> 00:00:33.940
And three squared is,
of course, equal to nine
00:00:33.940 --> 00:00:38.750
and five times nine is equal to 45.
00:00:38.750 --> 00:00:41.810
Let's do another example
that's a little bit different.
00:00:41.810 --> 00:00:44.610
Let's say I have the expression 1/3
00:00:44.610 --> 00:00:49.000
times six to the x power,
00:00:49.000 --> 00:00:53.800
and I want to evaluate it
when x is equal to two.
00:00:53.800 --> 00:00:56.443
Pause the video again and
see if you can work that out.
00:00:57.300 --> 00:00:59.590
Well, once again, everywhere
where we see an x,
00:00:59.590 --> 00:01:00.980
we'll replace that with a two.
00:01:00.980 --> 00:01:02.320
So this is going to be the same thing
00:01:02.320 --> 00:01:06.880
as 1/3 times six squared.
00:01:06.880 --> 00:01:10.360
Where we saw the x, we now
replace that with a two.
00:01:10.360 --> 00:01:12.780
And so this is going to be equal to,
00:01:12.780 --> 00:01:15.560
we do the exponent first,
order of operations,
00:01:15.560 --> 00:01:17.190
so it's going to be 1/3
00:01:17.190 --> 00:01:20.790
times six squared is 36,
00:01:20.790 --> 00:01:24.603
and 1/3 of 36 is equal to 12.
00:01:24.603 --> 00:01:25.771
And we're done!
|
Order of operations with fractions and exponents | https://www.youtube.com/watch?v=jAVbApE7lJ8 | vtt | https://www.youtube.com/api/timedtext?v=jAVbApE7lJ8&ei=ylWUZZ6BDvuKmLAPybmZeA&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245306&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=999A72AF0188C16F68A9C72B9B97FCDBCEE11941.3E0F741AED4352B5DB3969DC2A929E9E8E1515D0&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.360 --> 00:00:01.210
- [Instructor] Pause this video
00:00:01.210 --> 00:00:03.230
and see if you can
evaluate this expression
00:00:03.230 --> 00:00:05.460
before we do it together.
00:00:05.460 --> 00:00:07.850
All right, now let's
work on this together.
00:00:07.850 --> 00:00:10.720
And we see that we have a lot
of different operations here.
00:00:10.720 --> 00:00:12.720
We have exponents. We have multiplication.
00:00:12.720 --> 00:00:14.500
We have addition. We have division.
00:00:14.500 --> 00:00:16.280
We have parentheses.
00:00:16.280 --> 00:00:19.020
And so to interpret this properly,
00:00:19.020 --> 00:00:23.430
we just have to remind ourselves
of the order of operations.
00:00:23.430 --> 00:00:26.700
So you start with parentheses,
then go to exponents,
00:00:26.700 --> 00:00:28.050
then multiplication and division,
00:00:28.050 --> 00:00:30.470
then addition and subtraction.
00:00:30.470 --> 00:00:33.780
So we see that we're going
to, whatever is over here,
00:00:33.780 --> 00:00:35.510
we're eventually going to square it.
00:00:35.510 --> 00:00:38.510
That's the only place that
we have the parentheses.
00:00:38.510 --> 00:00:39.930
But how are we going to evaluate
00:00:39.930 --> 00:00:42.890
what's inside of these parentheses?
00:00:42.890 --> 00:00:45.660
So let's, then, think about, all right,
00:00:45.660 --> 00:00:49.810
we have an exponent here
that we can evaluate.
00:00:49.810 --> 00:00:53.490
We know that 2 squared is
the same thing as 2 times 2,
00:00:53.490 --> 00:00:55.730
which is the same thing as 4.
00:00:55.730 --> 00:00:57.790
No more exponents to evaluate.
00:00:57.790 --> 00:01:00.470
So then we go to
multiplication and division.
00:01:00.470 --> 00:01:04.820
So we know by how this
fraction sign is written
00:01:04.820 --> 00:01:06.640
that we need to evaluate the numerator
00:01:06.640 --> 00:01:09.380
and then divide it by
the entire denominator
00:01:09.380 --> 00:01:10.830
right over here.
00:01:10.830 --> 00:01:13.320
Now in this numerator, we
have to remind ourselves
00:01:13.320 --> 00:01:16.350
that we do this multiplication
before we do this addition.
00:01:16.350 --> 00:01:18.650
We don't just go left to right.
00:01:18.650 --> 00:01:20.780
So we know that it's 1 plus,
00:01:20.780 --> 00:01:23.560
and I could put parentheses
here to really emphasize
00:01:23.560 --> 00:01:25.510
that we do the multiplication first.
00:01:25.510 --> 00:01:26.880
So before this gets too messy,
00:01:26.880 --> 00:01:28.590
let me just rewrite everything.
00:01:28.590 --> 00:01:30.950
I'm going to do this
multiplication up here first,
00:01:30.950 --> 00:01:32.090
and actually in the denominator
00:01:32.090 --> 00:01:34.960
I'm going to do this
multiplication first as well.
00:01:34.960 --> 00:01:39.080
So this is all going to
simplify to 1 over 14
00:01:39.080 --> 00:01:41.770
or 1/14 times,
00:01:41.770 --> 00:01:43.450
Now this numerator here is going to be
00:01:43.450 --> 00:01:47.170
1 plus 4 times 3.
00:01:47.170 --> 00:01:49.303
4 times 3 is 12.
00:01:50.620 --> 00:01:53.640
All of that is going to be over
00:01:53.640 --> 00:01:57.220
7 plus 2 times 3,
00:01:57.220 --> 00:02:00.240
which is of course equal to 6.
00:02:00.240 --> 00:02:04.650
And then I am going to
have our plus 1 here,
00:02:04.650 --> 00:02:06.463
and then I square everything.
00:02:07.370 --> 00:02:11.270
Well now we can evaluate this numerator
00:02:11.270 --> 00:02:13.900
and this denominator.
00:02:13.900 --> 00:02:15.623
Find another color to do it in.
00:02:16.490 --> 00:02:18.710
This numerator, 1 plus 12,
00:02:18.710 --> 00:02:21.770
is going to be equal to 13.
00:02:21.770 --> 00:02:26.410
And 7 plus 6, interestingly,
is also equal to 13.
00:02:26.410 --> 00:02:28.740
So we 1/14 or 1 divided by 14
00:02:28.740 --> 00:02:30.930
times this whole thing squared,
00:02:30.930 --> 00:02:34.980
and inside you have 13
divided by 13 plus 1.
00:02:34.980 --> 00:02:38.090
Well, we know we need to do
division before we do addition.
00:02:38.090 --> 00:02:41.600
So we will want to evaluate this part
00:02:41.600 --> 00:02:43.940
before we do the addition.
00:02:43.940 --> 00:02:46.540
What is 13 divided by 13?
00:02:46.540 --> 00:02:48.610
Well that's just going to be equal to 1.
00:02:48.610 --> 00:02:52.840
So I can rewrite this as 1 over 14
00:02:52.840 --> 00:02:57.383
times 1 plus 1,
00:02:58.400 --> 00:02:59.880
all of that squared.
00:02:59.880 --> 00:03:03.640
And now we'll want to do this
parentheses. So let's do that.
00:03:03.640 --> 00:03:08.423
1 plus 1 is going to be
equal, of course, to 2.
00:03:09.400 --> 00:03:11.580
And then we're going to do the exponents.
00:03:11.580 --> 00:03:16.100
2 squared is, of course, equal to 4.
00:03:16.100 --> 00:03:19.870
And then we're going to
multiply 1 over 14 times 4.
00:03:19.870 --> 00:03:21.900
Now you could interpret
this, and they're equivalent.
00:03:21.900 --> 00:03:23.200
You could say, hey, this is the same thing
00:03:23.200 --> 00:03:26.040
as multiplying 1/14 times 4.
00:03:26.040 --> 00:03:27.680
Or you could say this is the same thing
00:03:27.680 --> 00:03:31.460
as multiplying 1 times 4 divided by 14.
00:03:31.460 --> 00:03:35.490
1 times 4 divided by 14.
00:03:35.490 --> 00:03:36.590
Either way you look at it,
00:03:36.590 --> 00:03:40.880
you're going to get 4
over 14, and we're done.
00:03:40.880 --> 00:03:42.440
If you want, you could rewrite this
00:03:42.440 --> 00:03:46.090
by dividing both the numerator
and the denominator by 2,
00:03:46.090 --> 00:03:48.730
and you could get 2 over 7.
00:03:48.730 --> 00:03:51.260
But that's how we can evaluate
00:03:51.260 --> 00:03:53.110
this pretty complex expression
00:03:53.110 --> 00:03:56.853
just step-by-step looking at
what we can simplify first.
|
Order of operations introduction | https://www.youtube.com/watch?v=eoYThjIAhOc | vtt | https://www.youtube.com/api/timedtext?v=eoYThjIAhOc&ei=ylWUZZ_bMv6ImLAP5uapgAM&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245306&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=12797E5387EAED05F7BD62A9E7FD80B571488289.852E48D9A15E5DF8161F021C2C1BDD970829CE0F&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.160 --> 00:00:01.200
- Every few months,
00:00:01.200 --> 00:00:04.760
you'll see an expression like
this go viral on social media
00:00:04.760 --> 00:00:06.610
because it looks simple
00:00:06.610 --> 00:00:09.490
but depending on how people
interpret this expression,
00:00:09.490 --> 00:00:11.800
they often get different answers.
00:00:11.800 --> 00:00:14.240
So first, why don't you pause this video
00:00:14.240 --> 00:00:18.550
and think about what you think
three plus two times five
00:00:18.550 --> 00:00:19.913
is equal to.
00:00:21.880 --> 00:00:24.260
All right, now let's work
through this together.
00:00:24.260 --> 00:00:26.560
Now some of you might
have interpreted this
00:00:26.560 --> 00:00:29.140
as we should just go from left to right.
00:00:29.140 --> 00:00:30.230
So you might've said, all right,
00:00:30.230 --> 00:00:32.280
let me first add three plus two.
00:00:32.280 --> 00:00:33.660
So I can do that part first,
00:00:33.660 --> 00:00:35.680
which is of course equal to five.
00:00:35.680 --> 00:00:39.850
And then I could multiply that times five.
00:00:39.850 --> 00:00:44.630
And that is going to get me to 25.
00:00:44.630 --> 00:00:47.170
Now others of you would have said no,
00:00:47.170 --> 00:00:49.410
that makes no sense at all.
00:00:49.410 --> 00:00:53.400
We know that we should do
some operations before others.
00:00:53.400 --> 00:00:57.130
For example, multiplication
should come before addition.
00:00:57.130 --> 00:00:58.990
And so if you follow that,
00:00:58.990 --> 00:01:03.490
you would do the two times
five first to get 10.
00:01:03.490 --> 00:01:06.830
And so this would become three plus 10,
00:01:06.830 --> 00:01:11.210
which is of course,
going to be equal to 13.
00:01:11.210 --> 00:01:13.073
Who do you think would be right?
00:01:14.020 --> 00:01:16.130
Well, it turns out that
the second way of doing it
00:01:16.130 --> 00:01:17.340
is the correct way
00:01:17.340 --> 00:01:19.100
and that's because we have something known
00:01:19.100 --> 00:01:21.920
as order of operations.
00:01:21.920 --> 00:01:25.290
And the order of operations
is the convention
00:01:25.290 --> 00:01:27.750
that mathematicians have decided to use
00:01:27.750 --> 00:01:31.127
in order for us to have one
way to interpret an expression
00:01:31.127 --> 00:01:33.810
like this and the order of operations
00:01:33.810 --> 00:01:35.760
are to do parentheses first.
00:01:35.760 --> 00:01:36.700
So, for example,
00:01:36.700 --> 00:01:40.700
if you really wanted to add
the three and the two first,
00:01:40.700 --> 00:01:43.180
you should put parentheses around it
00:01:43.180 --> 00:01:46.500
to say, hey, that's what
you've got to do first.
00:01:46.500 --> 00:01:49.360
But then after parentheses, do exponents,
00:01:49.360 --> 00:01:52.500
which is really, you could view
as repeated multiplication,
00:01:52.500 --> 00:01:54.900
then do multiplication and division.
00:01:54.900 --> 00:01:58.050
Then do addition and subtraction.
00:01:58.050 --> 00:02:01.910
Now, some people might just
memorize this as PEMDAS,
00:02:01.910 --> 00:02:05.340
or PEDMAS or something like that.
00:02:05.340 --> 00:02:06.290
And you can do that,
00:02:06.290 --> 00:02:08.220
but there's a rationale to this.
00:02:08.220 --> 00:02:09.600
Parentheses are just,
00:02:09.600 --> 00:02:11.520
the person who writing
the expression saying
00:02:11.520 --> 00:02:13.740
do this for sure first.
00:02:13.740 --> 00:02:14.710
But then if you think about it,
00:02:14.710 --> 00:02:17.490
exponents are repeated multiplication
00:02:17.490 --> 00:02:19.950
and multiplication is repeated addition.
00:02:19.950 --> 00:02:23.200
So you're doing the most
repeated things first,
00:02:23.200 --> 00:02:25.620
then next repeated things
like multiplication.
00:02:25.620 --> 00:02:27.910
And then you go straight to the addition.
00:02:27.910 --> 00:02:29.930
The reason why multiplication and division
00:02:29.930 --> 00:02:31.030
are on the same line
00:02:31.030 --> 00:02:33.480
and addition and
subtraction on the same line
00:02:33.480 --> 00:02:36.690
is the convention there
is just go left to right.
00:02:36.690 --> 00:02:40.420
So now that we are armed
with our order of operations,
00:02:40.420 --> 00:02:44.280
let's tackle another
slightly hairier expression.
00:02:44.280 --> 00:02:47.270
And I use the term hairy for
a little bit more complex.
00:02:47.270 --> 00:02:51.560
So two times 10, minus eight,
00:02:51.560 --> 00:02:56.170
divided by four, plus one.
00:02:56.170 --> 00:02:58.610
Pause the video and see
how you could evaluate this
00:02:58.610 --> 00:03:01.023
now that you know about
order of operations.
00:03:02.560 --> 00:03:04.470
All right, now let's do this together.
00:03:04.470 --> 00:03:06.480
We don't see any parentheses here.
00:03:06.480 --> 00:03:08.220
We don't see any exponents here
00:03:08.220 --> 00:03:12.170
but we do see some
multiplication and division here.
00:03:12.170 --> 00:03:14.360
So we could see it over here.
00:03:14.360 --> 00:03:16.070
This two times 10.
00:03:16.070 --> 00:03:19.470
And we also have this
eight divided by four.
00:03:19.470 --> 00:03:21.600
So that's what we're
going to want to do first.
00:03:21.600 --> 00:03:25.530
So that two times 10, that
is going to be equal to 20.
00:03:25.530 --> 00:03:29.010
The eight divided by four,
is of course, equal to two.
00:03:29.010 --> 00:03:34.010
And then we have 20 minus two plus one.
00:03:35.050 --> 00:03:38.420
And this is now going to get
us, if we go left to right,
00:03:38.420 --> 00:03:41.580
which we should do when we're
just adding and subtracting,
00:03:41.580 --> 00:03:46.580
is we get 20 minus two is 18, plus one,
00:03:46.630 --> 00:03:49.860
which is going to be equal to 19.
00:03:49.860 --> 00:03:51.270
And we're done.
00:03:51.270 --> 00:03:52.103
Now, you might say, well,
00:03:52.103 --> 00:03:54.980
what if we wanted someone to
add the four and the one first?
00:03:54.980 --> 00:03:56.170
Well, one way to do that
00:03:56.170 --> 00:03:59.300
is you could have added a
parentheses there to force it
00:03:59.300 --> 00:04:02.130
or you could have even written
your division differently.
00:04:02.130 --> 00:04:05.170
For example, you could use a fraction sign
00:04:05.170 --> 00:04:06.210
to make things clearer.
00:04:06.210 --> 00:04:08.620
If we wanted to add the
four plus one first,
00:04:08.620 --> 00:04:12.890
instead of writing eight divided
by four plus one like that,
00:04:12.890 --> 00:04:17.890
you could write eight over four plus one.
00:04:17.960 --> 00:04:21.240
Now of course, this is
fundamentally different
00:04:21.240 --> 00:04:22.560
than this right over here.
00:04:22.560 --> 00:04:25.190
'Cause here we would do the
eight divided by four first,
00:04:25.190 --> 00:04:26.600
then add the plus one,
00:04:26.600 --> 00:04:29.220
while here, you would
add the four plus one
00:04:29.220 --> 00:04:31.303
and then divide eight by that.
|
Quantitative electrolysis | https://www.youtube.com/watch?v=v5qQusbk-j0 | vtt | https://www.youtube.com/api/timedtext?v=v5qQusbk-j0&ei=ylWUZZq_J4_YxN8Plc-K6AQ&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245306&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=29BD327757A2E71D668C3580E20A1E69322D4C86.7106D66D5ED3F5789BCEDA5FA40F5F051CECE16E&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.350 --> 00:00:02.600
- [Instructor] We already know
that in an electrolytic cell,
00:00:02.600 --> 00:00:04.260
current or movement of electrons
00:00:04.260 --> 00:00:06.990
is used to drive a redox reaction.
00:00:06.990 --> 00:00:10.700
And if we look at a generic
reduction half-reaction,
00:00:10.700 --> 00:00:12.880
the stoichiometry of the half reaction
00:00:12.880 --> 00:00:15.580
shows how many electrons are needed
00:00:15.580 --> 00:00:18.610
to reduce a generic metal ion.
00:00:18.610 --> 00:00:22.780
For example, if we say that
our generic metal ion is M2+,
00:00:22.780 --> 00:00:27.560
it takes two electrons to
turn M2+ into the solid metal.
00:00:27.560 --> 00:00:32.560
So one mole of M2+ ions
requires two moles of electrons
00:00:33.110 --> 00:00:35.800
to form one mole of the metal.
00:00:35.800 --> 00:00:39.240
So we could use this mole
ratio of one mole of metal
00:00:39.240 --> 00:00:42.350
to two moles of electrons to figure out,
00:00:42.350 --> 00:00:44.840
say, how much of a metal is produced
00:00:44.840 --> 00:00:47.130
in an electrolytic reaction.
00:00:47.130 --> 00:00:48.480
So this is an example
00:00:48.480 --> 00:00:51.840
of a quantitative electrolysis problem.
00:00:51.840 --> 00:00:55.630
Moles of electrons are related
to the amount of charge
00:00:55.630 --> 00:00:58.540
that passes through the electrolytic cell
00:00:58.540 --> 00:01:02.687
because one mole of electrons
carries 96,485 coulombs.
00:01:04.890 --> 00:01:06.660
So we could set this up as a constant
00:01:06.660 --> 00:01:08.190
called Faraday's constant.
00:01:08.190 --> 00:01:10.390
So Faraday's constant is symbolized by F,
00:01:10.390 --> 00:01:15.390
and it's equal to 96,485
coulombs per mole of electrons.
00:01:16.460 --> 00:01:20.550
And charge is related to current
and time by this equation.
00:01:20.550 --> 00:01:23.440
So I is equal to Q over t;
00:01:23.440 --> 00:01:27.720
where I is the current; Q,
capital Q is the charge;
00:01:27.720 --> 00:01:29.240
and t is the time.
00:01:29.240 --> 00:01:33.200
Sometimes, you see a
lower case Q for charge.
00:01:33.200 --> 00:01:35.740
Charge is measured in coulombs,
00:01:35.740 --> 00:01:38.580
and time is in seconds.
00:01:38.580 --> 00:01:42.380
And one coulomb per second
is equal to one ampere,
00:01:42.380 --> 00:01:45.870
so current is measured in amperes.
00:01:45.870 --> 00:01:48.090
Next, let's look at a
conversion chart that shows
00:01:48.090 --> 00:01:51.500
how to approach quantitative
electrolysis problems.
00:01:51.500 --> 00:01:54.570
And let's start over here
with this box on the far left,
00:01:54.570 --> 00:01:57.900
which says that charge is
equal to current times time.
00:01:57.900 --> 00:01:59.970
This comes from our equation for current,
00:01:59.970 --> 00:02:02.000
I is equal to Q over t.
00:02:02.000 --> 00:02:04.550
So solving for charge, solving for Q,
00:02:04.550 --> 00:02:06.920
Q is equal to I times t
00:02:06.920 --> 00:02:10.190
or charge is equal to current times time.
00:02:10.190 --> 00:02:13.440
Charge is related to moles of electrons
00:02:13.440 --> 00:02:15.770
by Faraday's constant.
00:02:15.770 --> 00:02:19.000
So we can convert back
and forth between the two
00:02:19.000 --> 00:02:21.260
using Faraday's constant.
00:02:21.260 --> 00:02:24.690
And moles of electrons
are related to the moles
00:02:24.690 --> 00:02:27.320
of the substance that we're
interested in the problem
00:02:27.320 --> 00:02:29.500
by the balanced half-reaction.
00:02:29.500 --> 00:02:31.330
So the balanced half-reaction allows us
00:02:31.330 --> 00:02:34.310
to convert back and forth
between moles of electrons
00:02:34.310 --> 00:02:36.130
and moles of substance.
00:02:36.130 --> 00:02:37.380
And from stoichiometry,
00:02:37.380 --> 00:02:39.370
we know that the moles of a substance
00:02:39.370 --> 00:02:42.840
is related to the grams of the
substance by the molar mass.
00:02:42.840 --> 00:02:45.710
So the molar mass allows us
to convert back and forth
00:02:45.710 --> 00:02:47.580
between these quantities.
00:02:47.580 --> 00:02:49.640
So it helps to look at a conversion chart
00:02:49.640 --> 00:02:51.400
when doing these sorts of problems.
00:02:51.400 --> 00:02:53.910
However, if you don't remember the chart,
00:02:53.910 --> 00:02:56.860
you can always use
dimensional analysis and units
00:02:56.860 --> 00:02:59.460
to figure out the answer to the question.
00:02:59.460 --> 00:03:01.190
Next, let's use our conversion chart
00:03:01.190 --> 00:03:04.530
to figure out a quantitative
electrolysis problem.
00:03:04.530 --> 00:03:07.740
Let's say we have an aqueous
solution of silver nitrate
00:03:07.740 --> 00:03:12.740
and a constant current of
2.40 amperes is applied
00:03:12.940 --> 00:03:16.020
for 1,225 seconds.
00:03:16.020 --> 00:03:19.550
And our goal is to figure
out the mass of silver
00:03:19.550 --> 00:03:20.870
that has formed.
00:03:20.870 --> 00:03:24.290
As a quick reminder, an aqueous
solution of silver nitrate
00:03:24.290 --> 00:03:29.290
contains Ag+ ions and
nitrate anions in solution.
00:03:29.340 --> 00:03:34.150
So the applied current is
used to reduce the Ag+ ions
00:03:34.150 --> 00:03:36.570
to form solid silver.
00:03:36.570 --> 00:03:38.690
And since our goal is
to figure out the mass
00:03:38.690 --> 00:03:40.700
of the solid silver that's formed,
00:03:40.700 --> 00:03:44.130
we're trying to find grams of substance.
00:03:44.130 --> 00:03:49.130
And in the problem we're given
the current and the time,
00:03:49.230 --> 00:03:51.870
so we're starting over
here in the first box
00:03:51.870 --> 00:03:54.230
with the current and the time.
00:03:54.230 --> 00:03:56.450
So let's think about
the steps that we need
00:03:56.450 --> 00:03:58.410
to solve this problem.
00:03:58.410 --> 00:04:01.750
The first step is to find the charge,
00:04:01.750 --> 00:04:04.580
which we can get from
the current and the time.
00:04:04.580 --> 00:04:07.550
The second step is to convert charge
00:04:07.550 --> 00:04:10.440
into moles of electrons.
00:04:10.440 --> 00:04:11.900
From moles of electrons,
00:04:11.900 --> 00:04:16.900
we can convert that into the
moles of silver in this case.
00:04:17.070 --> 00:04:19.820
And in the fourth step for this problem,
00:04:19.820 --> 00:04:24.600
we can convert moles of
silver into grams of silver.
00:04:24.600 --> 00:04:28.240
So step one is to find the charge.
00:04:28.240 --> 00:04:32.440
And Q, the charge, is equal
to the current times the time.
00:04:32.440 --> 00:04:35.760
So the current is equal to 2.40 amperes.
00:04:35.760 --> 00:04:36.593
And remember,
00:04:36.593 --> 00:04:39.880
one ampere is equal to
one coulomb per second.
00:04:39.880 --> 00:04:44.610
So we plug in 2.40 coulombs per second.
00:04:44.610 --> 00:04:48.180
And the time is 1,225 seconds,
00:04:48.180 --> 00:04:51.260
so we plug that in, seconds cancels out,
00:04:51.260 --> 00:04:56.020
and we get that Q is
equal to 2,940 coulombs.
00:04:56.020 --> 00:05:00.440
So that's the charge that's
transferred in that time period.
00:05:00.440 --> 00:05:01.700
Now that we have the charge,
00:05:01.700 --> 00:05:02.810
in the second step,
00:05:02.810 --> 00:05:05.120
our goal is to find
the moles of electrons.
00:05:05.120 --> 00:05:07.730
And charge is related
to moles of electrons
00:05:07.730 --> 00:05:09.800
by Faraday's constant.
00:05:09.800 --> 00:05:13.340
So dividing the charge
by Faraday's constant
00:05:13.340 --> 00:05:15.330
causes coulombs to cancel out,
00:05:15.330 --> 00:05:20.330
and we get 0.0305 moles of electrons.
00:05:20.330 --> 00:05:22.280
And now that we have moles of electrons,
00:05:22.280 --> 00:05:26.230
in step three, we can
find the moles of silver.
00:05:26.230 --> 00:05:29.340
Looking at the balanced
equation for our half reaction
00:05:29.340 --> 00:05:32.540
showing the reduction of silver ions,
00:05:32.540 --> 00:05:37.540
one mole of silver ions
requires one mole of electrons
00:05:38.060 --> 00:05:41.240
to form one mole of solid silver.
00:05:41.240 --> 00:05:44.660
So our mole ratio of silver
to moles of electrons
00:05:44.660 --> 00:05:46.410
is one-to-one,
00:05:46.410 --> 00:05:48.800
which gives us this conversion factor
00:05:48.800 --> 00:05:52.810
of one mole of silver per
one mole of electrons.
00:05:52.810 --> 00:05:55.480
So if we multiply our moles of electrons
00:05:55.480 --> 00:05:59.240
by our conversion factor,
moles of electrons cancels out,
00:05:59.240 --> 00:06:03.630
and that gives us 0.0305 moles of silver.
00:06:03.630 --> 00:06:06.340
In this case, our mole
ratio was one-to-one,
00:06:06.340 --> 00:06:09.410
but if we were reducing
a different metal ion,
00:06:09.410 --> 00:06:11.910
our mole ratio might not be one-to-one.
00:06:11.910 --> 00:06:14.500
So we have to be extra careful on the step
00:06:14.500 --> 00:06:17.270
to make sure we get the right mole ratio.
00:06:17.270 --> 00:06:19.080
And since we have moles of silver,
00:06:19.080 --> 00:06:21.020
in our fourth and final step,
00:06:21.020 --> 00:06:24.980
we can convert moles of
silver into grams of silver.
00:06:24.980 --> 00:06:28.350
So multiplying moles of silver
by the molar mass of silver,
00:06:28.350 --> 00:06:31.750
which is 107.87 grams per mole,
00:06:31.750 --> 00:06:36.750
moles cancel and this gives
us 3.29 grams of silver.
00:06:37.190 --> 00:06:40.940
It's also possible to do
all four steps at once
00:06:40.940 --> 00:06:43.700
in a dimensional analysis approach.
00:06:43.700 --> 00:06:45.090
So looking at our units,
00:06:45.090 --> 00:06:50.090
if we multiply 1,225 seconds
by 2.40 coulombs per second,
00:06:51.460 --> 00:06:54.500
seconds cancels out and gives us coulombs.
00:06:54.500 --> 00:06:57.300
Multiplying that by one mole of electrons
00:06:57.300 --> 00:07:02.220
per 96,485 coulombs, cancels out coulombs.
00:07:02.220 --> 00:07:05.600
Next, we have our conversion
factor of one mole of silver
00:07:05.600 --> 00:07:07.640
per one mole of electrons,
00:07:07.640 --> 00:07:10.040
so moles of electrons cancels out.
00:07:10.040 --> 00:07:12.030
And multiplying that by the molar mass
00:07:12.030 --> 00:07:16.150
of 107.87 grams per one mole,
00:07:16.150 --> 00:07:18.640
moles of silver will cancel out
00:07:18.640 --> 00:07:22.410
and give us a final answer of 3.29 grams.
00:07:22.410 --> 00:07:25.953
So we get the same answer, no
matter which approach we take.
|
The Nernst equation | https://www.youtube.com/watch?v=PemB4mY4Jfk | vtt | https://www.youtube.com/api/timedtext?v=PemB4mY4Jfk&ei=ylWUZYOUKMawp-oPwrqr6Aw&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245306&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=D6E6C7C13D88C74500F5C4BC3615D7B90F408283.7F783879489F849CE5C42EE43919FAF8084C9026&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.320 --> 00:00:01.153
- [Instructor] We already know
00:00:01.153 --> 00:00:02.810
how to calculate cell potential
00:00:02.810 --> 00:00:04.160
when the reactants and products
00:00:04.160 --> 00:00:06.020
are in their standard states.
00:00:06.020 --> 00:00:08.650
However, what if that's not the case?
00:00:08.650 --> 00:00:11.180
We can find cell potential
when reactants and products
00:00:11.180 --> 00:00:12.680
are not in their standard states
00:00:12.680 --> 00:00:15.870
by using the Nernst equation,
which is shown here.
00:00:15.870 --> 00:00:17.660
And we're gonna call that cell potential
00:00:17.660 --> 00:00:20.580
the instantaneous cell potential.
00:00:20.580 --> 00:00:23.410
E cell is the instantaneous
cell potential,
00:00:23.410 --> 00:00:27.310
the cell potential or voltage
at a specific moment in time.
00:00:27.310 --> 00:00:30.920
E naught of the cell is the
standard cell potential.
00:00:30.920 --> 00:00:32.330
This is the cell potential
00:00:32.330 --> 00:00:33.900
when the reactants and products
00:00:33.900 --> 00:00:35.960
are in their standard states.
00:00:35.960 --> 00:00:38.520
R is the ideal gas constant.
00:00:38.520 --> 00:00:40.500
T is the temperature.
00:00:40.500 --> 00:00:43.590
N is the number of electrons transferred
00:00:43.590 --> 00:00:45.650
in the redox reaction.
00:00:45.650 --> 00:00:47.790
F is Faraday's constant.
00:00:47.790 --> 00:00:51.200
And Q is the reaction quotient.
00:00:51.200 --> 00:00:54.760
So, this is one way to
write the Nernst equation.
00:00:54.760 --> 00:00:57.750
And let's compare this
form of the Nernst equation
00:00:57.750 --> 00:01:00.210
to a simplified form.
00:01:00.210 --> 00:01:03.090
In the simplified form
of the Nernst equation,
00:01:03.090 --> 00:01:05.730
E of the cell is equal
to E naught of the cell,
00:01:05.730 --> 00:01:09.730
minus 0.0592 volts, divided by n,
00:01:09.730 --> 00:01:13.060
times the log of the reaction quotient Q.
00:01:13.060 --> 00:01:15.760
So, going back to the first
form of the Nernst equation,
00:01:15.760 --> 00:01:18.580
if we assume the temperature
is 25 degrees Celsius,
00:01:18.580 --> 00:01:20.190
or 298 Kelvin,
00:01:20.190 --> 00:01:22.620
we multiply that by
the ideal gas constant,
00:01:22.620 --> 00:01:24.520
divide that by Faraday's constant,
00:01:24.520 --> 00:01:27.650
and for changing natural log to log,
00:01:27.650 --> 00:01:31.340
then we end up with this
form for the bottom equation,
00:01:31.340 --> 00:01:35.800
0.0592 volts divided
by n times the log of Q
00:01:35.800 --> 00:01:39.430
for this second term
of the Nernst equation.
00:01:39.430 --> 00:01:42.620
You can use the Nernst equation
to quantitatively calculate
00:01:42.620 --> 00:01:46.030
the exact voltage at a
specific moment in time.
00:01:46.030 --> 00:01:48.380
However, we're gonna try to
think about the Nernst equation
00:01:48.380 --> 00:01:51.000
from a qualitative point of view.
00:01:51.000 --> 00:01:52.870
Let's use the Nernst equation to think
00:01:52.870 --> 00:01:56.160
about the instantaneous cell potential
00:01:56.160 --> 00:01:58.200
for a zinc copper cell.
00:01:58.200 --> 00:02:01.170
And we're gonna look at a
few different situations.
00:02:01.170 --> 00:02:02.550
In a zinc copper cell,
00:02:02.550 --> 00:02:05.830
solid zinc is oxidized
to zinc two plus ions
00:02:05.830 --> 00:02:10.310
and copper two plus ions are
reduced to form solid copper.
00:02:10.310 --> 00:02:13.060
The standard cell potential
for the zinc copper cell
00:02:13.060 --> 00:02:18.060
at 25 degrees Celsius is
equal to positive 1.10 volts.
00:02:18.090 --> 00:02:21.650
And our goal is to find the cell potential
00:02:21.650 --> 00:02:23.170
at the moment of time
00:02:23.170 --> 00:02:25.740
when the concentration
of copper two plus ions
00:02:25.740 --> 00:02:27.820
is equal to 1.0 Mueller
00:02:27.820 --> 00:02:31.410
and the concentration of zinc
two plus ions in solution
00:02:31.410 --> 00:02:34.550
is also equal to 1.0 Mueller.
00:02:34.550 --> 00:02:36.620
To find the instantaneous cell potential,
00:02:36.620 --> 00:02:41.010
we're gonna use the simplified
form of the Nernst equation.
00:02:41.010 --> 00:02:45.920
E naught of the cell is
equal to positive 1.10 volts.
00:02:45.920 --> 00:02:47.220
Next, let's think about n,
00:02:47.220 --> 00:02:50.900
the number of electrons
transferred in the redox reaction.
00:02:50.900 --> 00:02:53.060
So, looking at our equation here
00:02:53.060 --> 00:02:55.010
is a solid zinc going to zinc two plus,
00:02:55.010 --> 00:02:56.320
is a loss of two electrons,
00:02:56.320 --> 00:02:58.720
and copper two plus going to solid copper
00:02:58.720 --> 00:03:00.450
is a gain of two electrons.
00:03:00.450 --> 00:03:05.060
So, two electrons were
transferred and n is equal to two.
00:03:05.060 --> 00:03:09.310
So, I've gone ahead and made n
equal to two in our equation.
00:03:09.310 --> 00:03:12.400
Next, we need to think about
the reaction quotient Q.
00:03:12.400 --> 00:03:13.660
Q has the same form
00:03:13.660 --> 00:03:16.290
as the equilibrium constant expression.
00:03:16.290 --> 00:03:19.070
So, if we think about
the balanced equation,
00:03:19.070 --> 00:03:21.460
remember, pure solids are left out
00:03:21.460 --> 00:03:24.070
of equilibrium constant expressions.
00:03:24.070 --> 00:03:26.530
So, it would be the
concentration of products
00:03:26.530 --> 00:03:29.050
over the concentration of reactants.
00:03:29.050 --> 00:03:31.890
And therefore, Q is equal
to the concentration
00:03:31.890 --> 00:03:35.610
of zinc two plus ions,
divided by the concentration
00:03:35.610 --> 00:03:37.990
of copper two plus ions.
00:03:37.990 --> 00:03:39.610
Because our goal is to find
00:03:39.610 --> 00:03:41.720
the instantaneous cell potential
00:03:41.720 --> 00:03:44.830
when the concentrations are
both equal to one Mueller,
00:03:44.830 --> 00:03:47.560
Q is equal to one divided by one.
00:03:47.560 --> 00:03:49.600
So, Q is equal to one.
00:03:49.600 --> 00:03:53.010
And the log of one is equal to zero.
00:03:53.010 --> 00:03:55.710
Therefore this entire second term
00:03:55.710 --> 00:03:59.080
in the Nernst equation is equal to zero,
00:03:59.080 --> 00:04:01.590
which means the
instantaneous cell potential
00:04:01.590 --> 00:04:04.930
is equal to the standard cell potential.
00:04:04.930 --> 00:04:07.230
So, the instantaneous cell potential
00:04:07.230 --> 00:04:12.230
is equal to positive 1.10 volts.
00:04:12.390 --> 00:04:14.170
And this answer makes a lot of sense
00:04:14.170 --> 00:04:18.240
because standard state for solutions
00:04:18.240 --> 00:04:20.670
is a one Mueller concentration.
00:04:20.670 --> 00:04:23.160
Therefore, the
instantaneous cell potential
00:04:23.160 --> 00:04:25.840
is equal to the standard cell potential
00:04:25.840 --> 00:04:27.393
at this moment in time.
00:04:28.330 --> 00:04:31.400
Next, let's think about the
instantaneous cell potential
00:04:31.400 --> 00:04:34.130
when the concentration
of copper two plus ions
00:04:34.130 --> 00:04:36.030
is equal to 10.0 Mueller
00:04:36.030 --> 00:04:38.340
and the concentration
of zinc two plus ions
00:04:38.340 --> 00:04:40.890
is equal to 1.0 Mueller.
00:04:40.890 --> 00:04:43.880
The standard cell potential
at 25 degrees Celsius
00:04:43.880 --> 00:04:47.540
is still equal to positive 1.10 volts
00:04:47.540 --> 00:04:49.770
and n is still equal to two.
00:04:49.770 --> 00:04:52.370
So, we need to think about
the reaction quotient Q
00:04:52.370 --> 00:04:54.250
at this moment in time.
00:04:54.250 --> 00:04:56.280
The concentration of zinc two plus ions
00:04:56.280 --> 00:04:59.100
is equal to 1.0 Mueller so we plug that in
00:04:59.100 --> 00:05:01.230
and the concentration
of copper two plus ions
00:05:01.230 --> 00:05:03.610
is equal to 10.0 Mueller.
00:05:03.610 --> 00:05:08.610
So, at this moment in
time, Q is less than one.
00:05:09.140 --> 00:05:13.450
The log of a number less
than one is negative.
00:05:13.450 --> 00:05:15.807
Therefore, this second
term would be negative
00:05:15.807 --> 00:05:19.490
or less than zero.
00:05:19.490 --> 00:05:22.810
And since we are subtracting
a negative number,
00:05:22.810 --> 00:05:25.210
we would actually be adding that value
00:05:25.210 --> 00:05:28.140
to the standard cell potential,
00:05:28.140 --> 00:05:30.870
which means that the
instantaneous cell potential
00:05:30.870 --> 00:05:34.290
will be greater than the
standard cell potential.
00:05:34.290 --> 00:05:36.060
And if you went ahead and calculated
00:05:36.060 --> 00:05:39.070
the instantaneous cell potential
with the Nernst equation,
00:05:39.070 --> 00:05:42.730
you would find it's equal
to positive 1.13 volts,
00:05:42.730 --> 00:05:47.200
which is greater than positive 1.10 volts.
00:05:47.200 --> 00:05:49.890
Next, let's think about the
instantaneous cell potential
00:05:49.890 --> 00:05:52.300
when the concentration
of copper two plus ions
00:05:52.300 --> 00:05:55.280
is equal to 1.0 Mueller
and the concentration
00:05:55.280 --> 00:05:58.810
of zinc two plus ions is
equal to 10.0 Mueller.
00:05:58.810 --> 00:06:00.040
Going to the Nernst equation,
00:06:00.040 --> 00:06:03.840
the standard cell potential
is still positive 1.10 volts
00:06:03.840 --> 00:06:06.300
and n is still equal to two.
00:06:06.300 --> 00:06:09.450
So next, we think about
the reaction quotient Q.
00:06:09.450 --> 00:06:10.610
At this moment in time,
00:06:10.610 --> 00:06:12.850
the concentration of zinc two plus ions
00:06:12.850 --> 00:06:14.700
is equal to 10.0 Mueller
00:06:14.700 --> 00:06:17.050
and the concentration
of copper two plus ions
00:06:17.050 --> 00:06:19.270
is equal to 1.0 Mueller.
00:06:19.270 --> 00:06:24.250
So, at this moment in time,
Q is greater than one.
00:06:24.250 --> 00:06:28.260
The log of a number greater
than one is positive.
00:06:28.260 --> 00:06:30.680
Therefore the second term in our equation
00:06:30.680 --> 00:06:34.920
will be positive or greater than zero.
00:06:34.920 --> 00:06:38.460
And because we are
subtracting a positive number,
00:06:38.460 --> 00:06:40.790
we would be subtracting a value
00:06:40.790 --> 00:06:43.330
from the standard cell potential,
00:06:43.330 --> 00:06:46.080
which means that the
instantaneous cell potential
00:06:46.080 --> 00:06:49.580
will be less than the
standard cell potential.
00:06:49.580 --> 00:06:51.860
And if you plug the numbers
into the Nernst equation,
00:06:51.860 --> 00:06:54.840
you would find that the
instantaneous cell potential
00:06:54.840 --> 00:06:58.330
is equal to positive 1.07 volts,
00:06:58.330 --> 00:07:03.330
which is less than the standard
cell voltage of 1.10 volts.
00:07:03.480 --> 00:07:05.400
We just saw that at the moment in time
00:07:05.400 --> 00:07:07.500
when the concentration
of copper two plus ions
00:07:07.500 --> 00:07:08.930
is equal to 1.0 Mueller
00:07:08.930 --> 00:07:11.000
and the concentration
of zinc two plus ions
00:07:11.000 --> 00:07:12.910
is equal to 10.0 Mueller,
00:07:12.910 --> 00:07:14.940
the instantaneous cell potential
00:07:14.940 --> 00:07:18.220
is equal to positive 1.07 volts.
00:07:18.220 --> 00:07:20.850
Let's use this moment in
time as a starting point
00:07:20.850 --> 00:07:22.410
and let's think about what happens
00:07:22.410 --> 00:07:24.810
to the instantaneous cell potential
00:07:24.810 --> 00:07:27.340
as the reaction progresses.
00:07:27.340 --> 00:07:31.090
Remember that the instantaneous
cell potential is related
00:07:31.090 --> 00:07:32.660
to the instantaneous change
00:07:32.660 --> 00:07:35.760
in free energy, delta G, by this equation.
00:07:35.760 --> 00:07:39.420
Delta G is equal to negative nFE.
00:07:39.420 --> 00:07:41.140
Because we have a positive value
00:07:41.140 --> 00:07:43.110
for the instantaneous cell potential,
00:07:43.110 --> 00:07:45.930
if we plug in a positive
value into our equation
00:07:45.930 --> 00:07:48.060
because of the negative
sign in the equation,
00:07:48.060 --> 00:07:50.990
we would get a negative sign for delta G.
00:07:50.990 --> 00:07:52.570
And when delta G is negative,
00:07:52.570 --> 00:07:55.040
the reaction is thermodynamically favored,
00:07:55.040 --> 00:07:59.040
which means the reactants
will turn into products.
00:07:59.040 --> 00:08:00.890
And as the reactions turn into products,
00:08:00.890 --> 00:08:04.240
the concentration of zinc
two plus ions will increase
00:08:04.240 --> 00:08:08.380
and the concentration of copper
two plus ions will decrease.
00:08:08.380 --> 00:08:12.040
And think about what that does
to the reaction quotient Q.
00:08:12.040 --> 00:08:14.080
There would be an increase
in the concentration
00:08:14.080 --> 00:08:17.380
of zinc two plus ions and a
decrease in the concentration
00:08:17.380 --> 00:08:19.140
of copper two plus ions.
00:08:19.140 --> 00:08:23.690
So, Q would no longer be
equal to 10.0 over 1.0.
00:08:23.690 --> 00:08:26.360
We would see an increase in Q
00:08:26.360 --> 00:08:29.400
as the reactants turn into the products.
00:08:29.400 --> 00:08:33.730
An increased value of Q
means that the second term
00:08:33.730 --> 00:08:37.930
in the Nernst equation will
be a larger, positive number.
00:08:37.930 --> 00:08:40.800
So, if we subtract a
larger positive number
00:08:40.800 --> 00:08:42.650
than we did in the previous example
00:08:42.650 --> 00:08:44.800
from the standard cell potential,
00:08:44.800 --> 00:08:48.340
we would get a lower
instantaneous cell potential
00:08:48.340 --> 00:08:51.520
than positive 1.07 volts.
00:08:51.520 --> 00:08:53.500
So, what the Nernst equation tells us
00:08:53.500 --> 00:08:57.460
is as the reaction goes to the right,
00:08:57.460 --> 00:09:01.150
there is an increase in
Q and as Q increases,
00:09:01.150 --> 00:09:05.870
there's a decrease in the
instantaneous cell potential.
00:09:05.870 --> 00:09:08.390
So, we've just seen as the
reaction goes to the right,
00:09:08.390 --> 00:09:10.360
that's an increase in Q.
00:09:10.360 --> 00:09:11.850
And according to the Nernst equation,
00:09:11.850 --> 00:09:15.630
that's a decrease in the
instantaneous cell potential.
00:09:15.630 --> 00:09:17.700
And therefore, the
instantaneous cell potential
00:09:17.700 --> 00:09:20.530
would decrease from 1.07 volts.
00:09:20.530 --> 00:09:23.040
However, the voltage
would still be positive,
00:09:23.040 --> 00:09:26.010
which means that delta G
would still be negative,
00:09:26.010 --> 00:09:27.380
which means that the reaction
00:09:27.380 --> 00:09:29.810
is still thermodynamically favored.
00:09:29.810 --> 00:09:31.010
And so, this keeps happening.
00:09:31.010 --> 00:09:33.590
As the reaction goes to the
right, Q keeps increasing
00:09:33.590 --> 00:09:37.040
and the instantaneous cell
potential keeps decreasing.
00:09:37.040 --> 00:09:39.727
So, we had started out
at positive 1.07 volts
00:09:39.727 --> 00:09:41.470
and we saw that that had decreased
00:09:41.470 --> 00:09:44.140
and it keeps on decreasing,
keeps on decreasing.
00:09:44.140 --> 00:09:47.510
Eventually the
instantaneous cell potential
00:09:47.510 --> 00:09:49.550
will go to zero volts.
00:09:49.550 --> 00:09:51.210
And when the voltage goes to zero,
00:09:51.210 --> 00:09:53.310
if you plug in zero into our equation,
00:09:53.310 --> 00:09:55.820
delta G is equal to zero.
00:09:55.820 --> 00:09:57.700
And when delta G is equal to zero,
00:09:57.700 --> 00:10:00.020
the reaction is at equilibrium.
00:10:00.020 --> 00:10:01.740
And the reaction quotient Q
00:10:01.740 --> 00:10:05.060
is equal to the equilibrium constant K.
00:10:05.060 --> 00:10:08.540
So, if you were to plug in
the equilibrium constant K
00:10:08.540 --> 00:10:09.500
in for Q,
00:10:09.500 --> 00:10:12.710
you would find that
this entire second term
00:10:12.710 --> 00:10:15.610
would be equal to positive 1.10 volts
00:10:15.610 --> 00:10:18.370
and cancel out the
standard cell potential,
00:10:18.370 --> 00:10:22.350
giving an instantaneous
potential of zero volts.
00:10:22.350 --> 00:10:25.930
So, if we think about our
zinc copper cell as a battery,
00:10:25.930 --> 00:10:28.090
when the reaction reaches equilibrium,
00:10:28.090 --> 00:10:32.750
the voltage is equal to zero
and the battery is dead.
00:10:32.750 --> 00:10:34.780
Let's do a quick summary
of what we've learned
00:10:34.780 --> 00:10:36.090
from the Nernst equation.
00:10:36.090 --> 00:10:37.780
So, this is the simplified form,
00:10:37.780 --> 00:10:41.430
which is valid at 25 degrees Celsius.
00:10:41.430 --> 00:10:42.910
When Q is equal to one,
00:10:42.910 --> 00:10:45.430
the instantaneous cell potential
00:10:45.430 --> 00:10:48.480
is equal to the standard cell potential.
00:10:48.480 --> 00:10:50.040
When Q is greater than one,
00:10:50.040 --> 00:10:51.940
the instantaneous cell potential
00:10:51.940 --> 00:10:54.760
is less than the standard cell potential.
00:10:54.760 --> 00:10:56.200
When Q is less than one,
00:10:56.200 --> 00:10:57.820
the instantaneous cell potential
00:10:57.820 --> 00:11:00.700
is greater than the
standard cell potential.
00:11:00.700 --> 00:11:03.980
And when Q is equal to the
equilibrium constant K,
00:11:03.980 --> 00:11:07.990
the instantaneous cell potential
is equal to zero volts.
00:11:07.990 --> 00:11:12.290
When Q is equal to K and the
potential is equal to zero,
00:11:12.290 --> 00:11:14.680
the reaction is at equilibrium.
00:11:14.680 --> 00:11:16.850
However, for these first three situations,
00:11:16.850 --> 00:11:20.260
Q is not equal to K and the
instantaneous cell voltage
00:11:20.260 --> 00:11:21.940
is not equal to zero.
00:11:21.940 --> 00:11:25.683
Therefore, the reaction
is not at equilibrium.
|
Standard potential, free energy, and the equilibrium constant | https://www.youtube.com/watch?v=b2YI3AIs6l0 | vtt | https://www.youtube.com/api/timedtext?v=b2YI3AIs6l0&ei=ylWUZeGOMsS2mLAP5bSo-Ak&caps=asr&opi=112496729&xoaf=5&hl=en&ip=0.0.0.0&ipbits=0&expire=1704245306&sparams=ip%2Cipbits%2Cexpire%2Cv%2Cei%2Ccaps%2Copi%2Cxoaf&signature=686C1948F8D6048CC48D4C8D49624AD0C257773B.B6FE04DF1EB3164DA2D5CB720FA397EFE0B5219A&key=yt8&lang=en&name=Default&fmt=vtt | en | WEBVTT
Kind: captions
Language: en
00:00:00.480 --> 00:00:02.330
- [Instructor] For a
generic redox reaction
00:00:02.330 --> 00:00:05.440
where the reactants
turn into the products,
00:00:05.440 --> 00:00:09.550
the free energy is
related to the potential
00:00:09.550 --> 00:00:11.580
for the redox reaction.
00:00:11.580 --> 00:00:13.520
The equation that relates free energy
00:00:13.520 --> 00:00:16.940
and potential is given by delta G is equal
00:00:16.940 --> 00:00:19.770
to negative nFE.
00:00:19.770 --> 00:00:23.850
Delta G is the instantaneous
difference in free energy
00:00:23.850 --> 00:00:26.500
between the reactants and the products
00:00:26.500 --> 00:00:29.290
and refers to the number of electrons
00:00:29.290 --> 00:00:32.490
that are transferred
in the redox reaction.
00:00:32.490 --> 00:00:34.860
F is Faraday's constant,
00:00:34.860 --> 00:00:39.500
which tells us the charge
carried by one mole of electrons.
00:00:39.500 --> 00:00:44.500
So one mole of electrons
carries 96,485 coulombs.
00:00:44.850 --> 00:00:48.570
E refers to the potential
of the redox reaction.
00:00:48.570 --> 00:00:52.180
You could also call this the
voltage of the redox reaction.
00:00:52.180 --> 00:00:54.190
If the reactants and products are both
00:00:54.190 --> 00:00:55.620
in their standard states,
00:00:55.620 --> 00:00:58.790
we can add the superscript
naught to delta G
00:00:58.790 --> 00:01:01.580
and the superscript naught to E.
00:01:01.580 --> 00:01:04.980
So we can use this equation
to calculate delta G naught
00:01:04.980 --> 00:01:07.560
from E naught or vice versa.
00:01:07.560 --> 00:01:10.920
We could calculate E
naught from delta G naught.
00:01:10.920 --> 00:01:13.490
And remember that delta
G naught is connected
00:01:13.490 --> 00:01:17.740
to the equilibrium constant
K by this equation.
00:01:17.740 --> 00:01:22.420
Delta G naught is equal to
negative RT natural log of K,
00:01:22.420 --> 00:01:26.930
where R is the ideal gas constant
and T is the temperature.
00:01:26.930 --> 00:01:28.780
And because delta G naught is a part
00:01:28.780 --> 00:01:30.720
of both of these two equations,
00:01:30.720 --> 00:01:35.440
these two equations connect
the standard potential E naught
00:01:35.440 --> 00:01:39.420
to the standard change in
free energy delta G naught,
00:01:39.420 --> 00:01:43.280
which is then connected to
the equilibrium constant K.
00:01:43.280 --> 00:01:45.940
So let's look at an
example of a redox reaction
00:01:45.940 --> 00:01:49.210
where we know the value for the
standard potential E naught,
00:01:49.210 --> 00:01:52.430
and first we're gonna
calculate delta G naught.
00:01:52.430 --> 00:01:53.900
And then from delta G naught,
00:01:53.900 --> 00:01:57.520
we're gonna calculate the
equilibrium constant K.
00:01:57.520 --> 00:01:59.200
So here's our redox reaction,
00:01:59.200 --> 00:02:01.380
and we're gonna calculate delta G naught
00:02:01.380 --> 00:02:05.060
at 25 degrees Celsius from E naught.
00:02:05.060 --> 00:02:07.400
So for this redox reaction,
00:02:07.400 --> 00:02:11.330
E naught is equal to positive 1.54 volts,
00:02:11.330 --> 00:02:14.200
and our goal is to
calculate delta G naught
00:02:14.200 --> 00:02:16.560
at 25 degrees Celsius.
00:02:16.560 --> 00:02:18.390
In our redox reaction,
00:02:18.390 --> 00:02:22.520
silver one plus is being
reduced to solid silver,
00:02:22.520 --> 00:02:25.280
and solid chromium is being oxidized
00:02:25.280 --> 00:02:27.290
to chromium three plus.
00:02:27.290 --> 00:02:29.650
Now that we've identified
what's being oxidized
00:02:29.650 --> 00:02:31.290
and what's being reduced,
00:02:31.290 --> 00:02:35.500
let's write the oxidation
and reduction half reactions.
00:02:35.500 --> 00:02:37.980
So for our reduction half reaction,
00:02:37.980 --> 00:02:40.840
we have silver one plus
gaining an electron
00:02:40.840 --> 00:02:42.530
to form solid silver.
00:02:42.530 --> 00:02:45.270
And for the oxidation half reaction,
00:02:45.270 --> 00:02:48.530
solid chromium is turning
into chromium three plus
00:02:48.530 --> 00:02:50.940
and losing three electrons.
00:02:50.940 --> 00:02:52.070
Next, we need to figure out
00:02:52.070 --> 00:02:54.410
how many electrons are being transferred
00:02:54.410 --> 00:02:56.400
in our redox reaction.
00:02:56.400 --> 00:02:58.090
In the reduction half reaction,
00:02:58.090 --> 00:03:01.180
the silver one plus cation
is gaining an electron,
00:03:01.180 --> 00:03:03.730
but in the oxidation half reaction,
00:03:03.730 --> 00:03:06.960
solid chromium is losing three electrons.
00:03:06.960 --> 00:03:09.730
And we need to make the
number of electrons equal.
00:03:09.730 --> 00:03:13.130
Therefore, we need to multiply
the first half reaction
00:03:13.130 --> 00:03:16.060
through by a factor of three.
00:03:16.060 --> 00:03:19.460
So now when we add together our reactants,
00:03:19.460 --> 00:03:21.230
so all the reactants on one side
00:03:21.230 --> 00:03:24.000
and all the products on the other side,
00:03:24.000 --> 00:03:26.200
the three electrons cancel out
00:03:26.200 --> 00:03:29.440
and give us our overall redox reaction.
00:03:29.440 --> 00:03:31.210
Because three electrons,
00:03:31.210 --> 00:03:33.530
three moles of electrons
were being transferred
00:03:33.530 --> 00:03:38.530
in our redox reaction,
n is equal to three.
00:03:39.440 --> 00:03:41.360
And since we know that n is equal to three
00:03:41.360 --> 00:03:46.010
and the standard potential
is equal to +1.54 volts,
00:03:46.010 --> 00:03:47.790
we're ready to plug into our equation
00:03:47.790 --> 00:03:50.010
to calculate delta G naught.
00:03:50.010 --> 00:03:53.040
So I went ahead and
rewrote our redox reaction,
00:03:53.040 --> 00:03:56.280
and our goal is to
calculate delta G naught.
00:03:56.280 --> 00:03:57.830
We already know what n is,
00:03:57.830 --> 00:03:59.530
we already know what E naught is,
00:03:59.530 --> 00:04:02.070
and F is Faraday's constant.
00:04:02.070 --> 00:04:05.080
Here's our equation with
everything plugged in.
00:04:05.080 --> 00:04:06.470
N is equal to three.
00:04:06.470 --> 00:04:09.320
There were three moles
of electrons transferred
00:04:09.320 --> 00:04:12.920
in our redox reaction
per mole of reaction.
00:04:12.920 --> 00:04:14.430
F is Faraday's constant,
00:04:14.430 --> 00:04:19.420
which is 96,485 coulombs
per mole of electrons.
00:04:19.420 --> 00:04:23.480
And the standard voltage
was equal to 1.54 volts.
00:04:23.480 --> 00:04:26.700
One volt is equal to
one joule per coulomb,
00:04:26.700 --> 00:04:28.270
so I went ahead and changed the units
00:04:28.270 --> 00:04:31.530
from volts to joules per coulomb.
00:04:31.530 --> 00:04:33.800
Next, we can cancel out some units.
00:04:33.800 --> 00:04:37.140
So moles of electrons will cancel out,
00:04:37.140 --> 00:04:39.610
and coulombs will cancel out,
00:04:39.610 --> 00:04:43.000
and that gives us joules
per mole of reaction.
00:04:43.000 --> 00:04:44.030
And after we do the math,
00:04:44.030 --> 00:04:47.170
we find that delta G naught
at 25 degrees Celsius
00:04:47.170 --> 00:04:49.210
for this redox reaction is equal
00:04:49.210 --> 00:04:53.360
to -4.46 times 10 to the 5th joules
00:04:53.360 --> 00:04:55.130
per mole of reaction.
00:04:55.130 --> 00:04:56.100
We could also write this
00:04:56.100 --> 00:04:58.770
in terms of kilojoules
per mole of reaction.
00:04:58.770 --> 00:05:00.040
So delta G naught is equal
00:05:00.040 --> 00:05:04.800
to -446 kilojoules per mole of reaction.
00:05:04.800 --> 00:05:07.150
Notice that a positive voltage
00:05:07.150 --> 00:05:10.250
and the negative in the equation means
00:05:10.250 --> 00:05:13.750
that we get a negative
sign in the final answer.
00:05:13.750 --> 00:05:15.990
And when delta G naught is negative,
00:05:15.990 --> 00:05:19.300
the reaction is thermodynamically favored,
00:05:19.300 --> 00:05:22.070
which means at 25 degrees Celsius,
00:05:22.070 --> 00:05:24.950
silver cations will
react with solid chromium
00:05:24.950 --> 00:05:29.210
to form solid silver and
chromium three plus ions.
00:05:29.210 --> 00:05:31.330
And what this example shows us is
00:05:31.330 --> 00:05:33.360
whenever the voltage is positive,
00:05:33.360 --> 00:05:36.540
that means a thermodynamically
favored reaction
00:05:36.540 --> 00:05:40.300
because delta G naught will be negative.
00:05:40.300 --> 00:05:43.030
Now that we've calculated delta
G naught for our reaction,
00:05:43.030 --> 00:05:45.650
let's calculate the equilibrium constant K
00:05:45.650 --> 00:05:47.940
at 25 degrees Celsius.
00:05:47.940 --> 00:05:50.500
So we need to plug in our
value for delta G naught,
00:05:50.500 --> 00:05:54.160
the ideal gas constant,
the temperature in Kelvin,
00:05:54.160 --> 00:05:57.640
and we'll solve for the
equilibrium constant.
00:05:57.640 --> 00:06:00.450
I've gone ahead and plugged
everything into our equation.
00:06:00.450 --> 00:06:02.480
So here's the value for delta G naught
00:06:02.480 --> 00:06:04.960
in joules per mole of reaction.
00:06:04.960 --> 00:06:08.560
The ideal gas constant
is equal to 8.314 joules
00:06:08.560 --> 00:06:10.700
per Kelvin mole of reaction.
00:06:10.700 --> 00:06:14.390
And 25 degrees Celsius,
if we add 273 to that,
00:06:14.390 --> 00:06:17.360
we get 298 Kelvin.
00:06:17.360 --> 00:06:20.500
Looking at the units, Kelvin cancels out
00:06:20.500 --> 00:06:24.630
and so does joules per mole of reaction.
00:06:24.630 --> 00:06:25.970
And solving for K,
00:06:25.970 --> 00:06:29.270
the equilibrium constant
is approximately equal
00:06:29.270 --> 00:06:32.060
to 10 to the 78th power.
00:06:32.060 --> 00:06:35.480
And since K is such an
extremely large number,
00:06:35.480 --> 00:06:38.780
that tells us the reaction
essentially goes to completion,
00:06:38.780 --> 00:06:42.020
and all the reactants turn into products.
00:06:42.020 --> 00:06:43.560
So for a reaction like this,
00:06:43.560 --> 00:06:47.410
it's not necessary to have
equilibrium arrows in here.
00:06:47.410 --> 00:06:50.970
We can just draw an
arrow going to the right.
00:06:50.970 --> 00:06:54.730
And remember, we started with
a positive standard potential
00:06:54.730 --> 00:06:56.710
for this redox reaction.
00:06:56.710 --> 00:06:59.510
So to summarize what we've
seen with these calculations,
00:06:59.510 --> 00:07:02.360
a positive value for the
standard potential leads
00:07:02.360 --> 00:07:05.000
to a negative value for delta G naught,
00:07:05.000 --> 00:07:08.350
so a thermodynamically
favored redox reaction.
00:07:08.350 --> 00:07:10.980
And a negative value
for delta G naught leads
00:07:10.980 --> 00:07:15.010
to an equilibrium constant
K that is greater than one.
00:07:15.010 --> 00:07:17.680
We've just seen what
happens to delta G naught
00:07:17.680 --> 00:07:20.060
and the equilibrium constant K
00:07:20.060 --> 00:07:23.270
when the standard potential is positive
00:07:23.270 --> 00:07:24.950
or greater than zero.
00:07:24.950 --> 00:07:28.030
Now let's think about a
generic redox reaction
00:07:28.030 --> 00:07:31.010
where the standard potential is negative,
00:07:31.010 --> 00:07:33.660
so E naught is less than zero.
00:07:33.660 --> 00:07:36.230
So let's think about the
sign for delta G naught
00:07:36.230 --> 00:07:40.760
if we plug in a negative value
for the standard potential.
00:07:40.760 --> 00:07:42.770
So if we have a negative voltage,
00:07:42.770 --> 00:07:45.890
the two negative signs in the equation
00:07:45.890 --> 00:07:49.330
will give us a positive
value for delta G naught.
00:07:49.330 --> 00:07:52.060
A positive value for delta G naught means
00:07:52.060 --> 00:07:54.246
that the forward reaction
00:07:54.246 --> 00:07:56.560
of reactants turning into products
00:07:56.560 --> 00:08:00.620
is a thermodynamically
unfavorable reaction.
00:08:00.620 --> 00:08:03.030
And if we were to plug in a positive value
00:08:03.030 --> 00:08:04.600
for delta G naught,
00:08:04.600 --> 00:08:07.300
we would find that the
equilibrium constant K
00:08:07.300 --> 00:08:09.580
would be less than one.
00:08:09.580 --> 00:08:11.200
And when K is less than one,
00:08:11.200 --> 00:08:15.000
that tells us whenever the
reaction reaches equilibrium,
00:08:15.000 --> 00:08:19.220
there will be a lot more
reactants than products.
00:08:19.220 --> 00:08:20.640
Let's look at a quick summary
00:08:20.640 --> 00:08:22.940
of what we've learned from these examples.
00:08:22.940 --> 00:08:24.600
The standard potential E naught
00:08:24.600 --> 00:08:27.440
and the standard change in
free energy delta G naught
00:08:27.440 --> 00:08:30.040
are related by the equation on the left.
00:08:30.040 --> 00:08:31.330
And delta G naught
00:08:31.330 --> 00:08:34.160
and the equilibrium constant K are related
00:08:34.160 --> 00:08:36.340
by the equation on the right.
00:08:36.340 --> 00:08:38.000
When E naught is greater than zero,
00:08:38.000 --> 00:08:40.160
delta G naught is less than zero,
00:08:40.160 --> 00:08:43.280
and the reaction is
thermodynamically favored,
00:08:43.280 --> 00:08:45.320
which means at equilibrium,
00:08:45.320 --> 00:08:47.270
there'll be more products than reactants,
00:08:47.270 --> 00:08:50.950
and the equilibrium constant
K will be greater than one.
00:08:50.950 --> 00:08:53.310
However, when E naught is less than zero,
00:08:53.310 --> 00:08:55.680
delta G naught is greater than zero,
00:08:55.680 --> 00:08:58.970
and the reaction is
thermodynamically unfavored,
00:08:58.970 --> 00:09:00.830
which means at equilibrium,
00:09:00.830 --> 00:09:03.140
there'll be more reactants than products,
00:09:03.140 --> 00:09:06.733
and the equilibrium constant
K will be less than one.
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