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|---|---|---|---|
bswrqm
|
Why does water taste sweet after throwing up?
|
I think it has something to do with the fact that water doesn't taste bitter, and your vomit does, and overloaded your tastebuds with bitter taste.
|
c8628268-87f9-4d29-a85f-be052c94305f
|
bswxfi
|
OS (C:) vs DATA (D:)
|
It's just two separate drives. The separation can be physical (i.e. The drives are two physically separate drives) or it can be logical (there's only one actual physical drive, split into two partitions).
If the separation is logical, then it's entirely up to whoever installed the machine. It's common to make a smaller partition for the operating systems and some of the installed software, and a larger partition for all the data - documents, pictures, videos and such. That way you can easily delete the entire system partition without touching the data partition (for example if you want to reinstall your operating system from scratch) However this separation isn't required - it's also possible to have just one drive with just one partition which holds everything, both the programs and the data.
Nowadays computers often come with two drives - an SSD (solid state drive) and an HDD (hard disk drive). SSDs are faster but smaller and more expensive than HDDs, so you usually have a small SSD for the operating system and programs (which benefit from fast access to the drive) and a large HDD for the data (which doesn't need to be as fast).
|
030564d8-31e1-4e35-aeee-cba482c32056
|
bswz2p
|
Image sizes. If the camera settings stays the same and the image is stored as a set of pixel values, why does the image size change?
|
The images are likely being compressed.
Say for example you take a picture of someone in front of a flat white wall. Uncompressed the photo file would have to explicitly store that every single individual pixel of the wall is white, while a compressed file would store “all the pixels between *here* and *here* is white.
Uncompressed: 1, white 2, white 3, white 4, white...
Compressed 1 - 4, white.
Photos of highly varied and colorful scenes can’t be compressed as much and therefore the file is larger.
|
db631186-2a51-4ab6-a6b4-cc7c72fa86f4
|
bsx30e
|
Why are wooden houses more common in the U.S when block/brick houses are more common in Europe?
|
Wood is really, *really* cheap in the US. It is easily the least expensive and quickest way to build a house.
Concrete block houses are more common in hurricane-prone areas that have strict codes.
|
1704ed60-f180-4372-8c99-201d5bd38887
|
bsx8b6
|
Why has there been an increase in reported vision problems in the last 100 or so years? Myopia, Hyperopia, Presbyopia, and Astigmatism in particular.
|
Dont forget that it is a lot easier to have eye checkups nowadays and therefore theres a lot more diagnosis of these problems.
Myopia and presbyopia are mostly caused by the shape of the eyes, so that the lenses in your eyes cant project the image correctly on your retina = blurred vision. So blue lights as mentionned by some are not really the problem
|
2a87dd52-b151-48ba-9e82-d1fd4a1ef2f2
|
bsxe4b
|
How does medication expire and what makes them potentially “dangerous”?
|
Most medication really doesn't expire. After awhile it can be less effective.
_URL_0_
But some drugs like insulin and liquids can break down and be dangerous to use if not stored properly
|
050ba31e-8ccb-4102-a7b9-d7834ec4f993
|
bsxe8l
|
how do package trackers for UPS & Amazon work?
|
Each package is assigned a number, which is why you get a tracking number you can use to see where it was last seen.
That number is entered into a computer database. When the package is loaded onto or off of a truck/plane that number is scanned and tagged with the time and location where it was scanned.
The computer makes a best guess on when the package will arrive based on all of the scheduled travel between the package’s origin and destination.
|
216e074a-0557-4c4d-9231-791beef604b3
|
bsxf7h
|
Why do cold feet always sting when you enter a hot tub?
|
Your skin is covered in temperature sensitive cells. They are what tells you that something is too hot or cold. But the way they do so is dependent on the temperature your body has been at recently. If it goes too far in either direction, these things start going off like alarms.
The sudden change in temperature from cold to hot makes your body think you're touching something you shouldnt be, something too hot. The stinging / burning sensation is your body trying to make you stop doing that.
Eventually though the cells establish a new base, safe temperature for the situation, and you stop feeling the stinging because it doesn't detect any problems.
WHich is also why jumping into a cool pool immediately after a hot tub causes the same sensation.
A semi-related bonus fact: this is the same reason why alcohol burns when you drink it. The alcohol confuses those temperature sensitive cells and reduces their threshold, so your own body heat is enough to set them off.
|
31464a07-5dcd-4b4e-bb56-8546e82e86f6
|
bsxggk
|
Why do the Japanese refer to themselves with their family names in public? When is it okay to call them by their first names?
|
Only if you're very close to them is it okay to call then by their first name. It's an intimacy thing, while adding -san, -kun, -chan, -sama, -dono to their names is a respect thing.
If someone's name is Bob Bobbins, you'd call then Bobbins-san if you don't know them. If someone is a higher rank than you (leaders etc), you add -sama to their name. If you're both of the same rank in a formal situation, you go with -dono. If someone is your junior, you go with -kun. If it's a kid, -chan is apropriate. If you're bedfellows you'd probably drop all that and go straight for Bob.
I might be wrong on this since I'm just a semi-weeb, but I hope it helps.
|
9ec73daf-e592-4948-8f3d-c92697eebee8
|
bsxpmc
|
Why dont sperm banks keep sperm warm like our bodies do rather than freezing it?
|
Freezing it puts it into a sort of suspended animation and preserves it. If they kept it warm then they would live their natural very short life cycle as cells (about 5 days) and without testes resupply while in the bank it makes collecting it in the first place useless. Being stored warm also makes it more likely to be contaminated with atmospheric bacteria and fungi.
|
3ce49cb0-b377-455e-8f9e-e300ff8fa080
|
bsxr4q
|
What happens in the brain when catchy songs get stuck in our head for days?
|
If we had true answers to stuff like this, we'd likely be using to train folks. At least musicians of not also doctors and scientists.
Not a ton of research has been done on the matter but basically we know that "catchier" songs are more popular on charts and such which kind of makes intuitive sense. We also know that there is a slight predisposition associated/corelated with music appreciation. Research also shows that the song parts that get stuck in heads tend to be 15 to 30 seconds long.
There's other studies that suggest that simpler songs may be catchier. And that familiarity lends itself into catchyness. As an example that "somebody I used to know" song from a few years ago afflicted many people. That may partially be due to it's similarities with "ba ba black sheep" that many children grew up with.
Along the lines of familiarity, the brain spends a lot of time predicting things so that it doesn't have to react to new things all of the time. Music is rythmnic and patternistic. Brains love patterns. Patterns, routines, etc are all things our brains have evolved to be good at.. as such, folks may find themselves getting songs suck in their heads whole song routine activities such as jogging, driving, and cleaning.
I don't have a biological answer for you. As far as I am concerned, the biology of the brain is all black magic.. and I am not really a psychologist either.
|
e169ea06-65b5-48ca-9e6c-02c5a01fde11
|
bsxuzq
|
How is it that a couple can have HIV negative children despite one or both of them being HIV positive?
|
I'm a family medicine resident so somewhat qualified I guess to answer. The transmission rate from mom to infant is only something like 10% without hiv treatment, this is because most of the time the virus does not cross the placenta. Sometimes it does and there is a riks of transmission to baby during delivery. If a mom is treated with antiretroviral therapy and has very low viral levels the transmission rate can be close to 0.
|
8957d63c-d0c0-4779-b7cb-f160fb76d376
|
bsy8z0
|
How do the saws used to remove casts not break skin?
|
It doesn’t actually rotate, it just vibrates back and forth, it ‘cuts’ through the cast because its hard and sturdy, when it hits your skin it does no damage as your skin actually moves with it due to its flexibility.
|
615d02b0-6527-4086-bf72-770a974eee1b
|
bsya0d
|
How do paleontologists recreate a whole skeleton out of five bones and one tooth?
|
Bones and teeth are matched to find similar bones and teeth, then based on where they match, they make up the rest.
For example, a shark tooth. We have living sharks which have teeth. When a huge shark tooth is dug up, the nearest living match to the tooth found is scaled up to the size of the found tooth, along with large sharks (whale shark) found today and they guess that it would look like the [Megalodon](_URL_1_), without any actual truth that it did not look like [Zirga](_URL_0_)
|
87500157-75a6-46a5-bff9-97d85b712ddb
|
bsyap6
|
What does DJ Khaled really do in a song? Like what's his job about beside randomly shouting his name in the track?
|
Dj Khaled is a songwriter and producer. So, while it may seem that all he does is yell WEDABEST!!!, he actually helps write lyrics and create the beats to his songs. Then he tries to find other artists to get on his track.
|
1243b6b3-2e8b-4249-8f75-66bb142753dd
|
bsyc30
|
How does the wind "carry" noise?
|
Sound is air molecules bumping into each other at different frequencies. The wind moves there particles forward, giving them energy to hit harder, and that's why the sound seems louder when the wind is "carrying" it
|
e7bb8712-25d0-4050-b35d-ceb66dc81982
|
bsyi64
|
why is keeping ice on the skin bad, but keeping organs on ice preserves them?
|
Because they're not placed directly on ice. Great care is taken not to damage them and they're usually wrapped in some form of protective film
|
74455eed-60fb-45f9-90da-6e292ebc7894
|
bsym9u
|
How does a banana get more sugary after it over-ripens, even after it is cut off of its tree?
|
All the sugar is already in the banana but it is woven in long threads that don't taste sweet in mouth. When it ripens the threads break down and we can taste the sugar again.
|
ee17a91d-5174-44a8-8ee3-8b2daefdeade
|
bsyq9k
|
Why are some animals like birds and reptiles born from eggs while most mammals are not?
|
Everyone is born in an egg. Just some species keep the eggs inside mommy till they hatch and some pop the egg out early to hatch in the nest.
|
031cebc3-7f72-4314-8d47-62e6e6977ffe
|
bsz3qp
|
How do random glitches happen on computers and smart phones when the code is perfectly fine?
|
They happen because the code is never perfectly fine. There are errors in any software. The code just mostly works, while in a stable situation. Once in a while something unexpected happens - like a network loss, or a hardware problem, or some weird user input - and the software might not be ready for this kind of scenario. This is when you see a glitch.
|
964e8fb3-52f2-48e3-982b-349224fa5047
|
bsz59w
|
How does a bleeding bumhole not get infected?
|
It for sure can, which is why you should keep an eye on things & contact your doctor if anything new starts to happen.
|
ac506a90-0757-48e3-8452-af51e719df2a
|
bszhcb
|
Cascading in database?
|
In an SQL database you can define a Foreign Key from one table to another. For example if you have a "students" table and a "teachers" table, you can have a "homeroom teacher" column in the students table, which holds the ID (primary key) of one the teachers in the teachers table. This is defined as a foreign key.
But, what happens if a teacher is deleted? Every student which referenced that teacher would now have an invalid value in their "homeroom teacher" column.
ON DELETE CASCADE tells the database that when the teacher is deleted, every student which referenced that teacher should also be deleted. Similarly, ON DELETE SET NULL simply sets the "homeroom teacher" value for each of these students to null, instead of deleting them. Another option is ON UPDATE CASCADE which says that if the ID of the teacher changes, then the referenced ID of that teacher's students would change accordingly.
|
acec9842-dcef-4010-b39f-82a2e49a21ca
|
bszxnf
|
How does staying hydrated work? Why don’t we drink electrolyte solutions like pedialyte daily in addition to water to maintain hydration?
|
You’re getting enough electrolytes if you eat normally. So in that case regular water is fine. You only run into problems if you’re not able to eat normally due to some kind of major illness.
|
d490eea2-48cd-48d4-b6ae-4a402149cf55
|
bszz8y
|
how can we hear people’s voices through a phone? How can our voices travel across the world through a mobile?
|
Voices are sound waves. A sound wave is a change in air pressure, and you can describe all the information in a sound wave by describing the change in pressure over time.
To make voices into electricity in your phone, you put a diaphragm near an electromagnet. When you talk, the air pressure makes the diaphragm move, and that makes electricity in the electromagnet. Now, instead of a change in pressure over time, we are dealing with a change in voltage over time.
If you hook the electromagnet up to wires, and hook those wires up to a computer, you can convert the changing voltage into a series of numbers. This is a better way of recording sound, because once you have numbers, you can design error-correction techniques to ensure you don't lose any data. If you have trouble connecting one computer to another, you can store the numbers and resend them later, etc. Putting it in numbers gives you flexibility.
Now that you have the voice recorded in numbers, you need to convert it again: this time, into a radio wave. This is also voltage over time, but instead of electrons in a wire, it is electromagnetic waves through space. Those waves go from your phone to a cell tower and are converted back into numbers. Then they may be converted into waves again, or put back over a wire. Either way, the numbers are broken up into groups called packets and put back together once they get to their destination. This is so each packet can choose the best route to the destination, instead of the whole message having to follow the same route. This makes things faster.
At the destination, the whole process runs in reverse: radio waves or voltage on a wire back into numbers again. Then numbers back into radio waves from another cell tower, which are picked up by the other person's phone, and turned back into voltage on a wire. The voltage on a wire is hooked up to a diaphragm next to an electromagnet - it looks a lot like the microphone you spoke into, but is designed a little differently. This time, the electromagnet moves the diaphragm, and the diaphragm pushes on the air to replicate the sound of your voice.
|
68209f20-67d3-45f0-913b-dcdd93e69cce
|
bt008l
|
; why is none of something pluralised?
|
In this case the plural is also the collective noun. You're not really talking about *any* amount of apples but rather the concept of apples (specifically your lack of possession).
Or another way: It's because what you're *really* doing is saying in one statement that you do not have each and every apple, so you use the plural.
The singular (generally) refers to a specific apple, whether positive or negative.
"I have no apple" is totally acceptable, but it kinda implies (a tiny bit) that you have a particular apple in mind that you lack. :p
|
f4ec9f43-7b12-40a6-8f27-d89024e77881
|
bt03lt
|
why do stop lights make you press the walk sign button?
|
If no-one needs to cross the road, it would be pointless to stop the traffic. By requiring pedestrians to press the button you can keep the traffic interruptions to a minimum and only when there is actually someone who needs to cross.
|
49a66dfc-15da-4d07-8e48-37d990277398
|
bt04qz
|
What does this helium shortage mean? Can we make more? Isn’t it important?
|
In order:
It will mean that we can't run things like the LHC, MRIs, and other machines that needs to be super-cold or have extremely strong magnets. We also can't do certain sorts of studies on physics.
We can't make it, because it only comes from nuclear decay. We happen to get it when we harvest natural gas, but much of it is lost to space in that process.
It's very important, but also very hard to store. There's only one storage facility in the US that stores it with no loss to space. The only way we could start making it is though fusion, which is a long way off and would probably involve those super-strong magnets again.
So right now, the best thing to do would be to lobby the government to stop wasting our strategic supply on stuff. Also, no more Macy's Thanksgiving day parade and party balloons (though there is an ~~mildly insane~~ alternative plan to fill them with hydrogen). But we really need to government's help to store it, because they control a majority of the supply.
|
f30c455d-58e6-46e8-91bf-f43cd4915502
|
bt05kd
|
WTF is “micellar water” and how does it work?
|
It’s basically teeny tiny beads of oil suspended in water. The oil and dirt in the skin are attracted to the micellar water solution which allows it to pull dirt from the skin. Here’s one [description.](_URL_0_)
|
7442bc85-2f0a-45d0-bf54-63a274de8ee6
|
bt0lgo
|
How did the cliché of getting hit by a falling piano or anvil come about?
|
Not the exact same trope, but possibly it started with [this Buster Keaton skit from 1920](_URL_0_).
|
f103958b-0bca-4fbe-9437-aa17bd475bca
|
bt0sro
|
What causes people to pass out on fast rides?
|
The heart pumps blood to the brain to keep you conscious. The brain is located higher in your body than your heart, so the heart usually has to pump against gravity to get blood to your brain. This usually isn't much of a challenge for the heart in a healthy person, but it still requires the heart to pump at a high enough pressure to overcome gravity.
Now, when you're on a rollercoaster ride, the heart has to pump against a much greater force. Newton's third law states that for every force acting on an object, there is an equal and opposite force. So that means that, while there is a great force lifting you up into the air, there is also a great force pushing you down into the seat.
This force doesn't just affect your outer body, but also your blood. So your heart essentially has to pump against gravity plus the force lifting you up, which is much harder. When not enough blood can get to your brain, the part of your brain that keeps you awake shuts down to keep you alive by using the blood on the parts of the brain that keep your internal organs going.
You're also more likely to pass out if you're screaming a lot or if you're very scared. This is because, in these situations, your blood vessels become narrower, so even less blood can get through to your brain.
On the other hand, genetics and training can reduce this effect by making your heart better at pumping blood.
|
19823f47-3dec-4049-868e-a4ea71955ab2
|
bt0xgw
|
What does your car radio sometimes lose signal when you come to a stop sign or stoplight, then comes in clear again when you roll forwards a few inches/feet?
|
It's due to "multipath interference". On its way to your radio antenna, a radio wave can also bounce off various things (buildings, trees, cars, etc.). The reflected versions of these multiple paths take a little longer to get to your antenna than the most direct one, so they are out of phase with the original. (The peaks and troughs don't line up.) This can cause destructive interference to occur, degrading the radio signal. (It can also result in *constructive* interference.)
If you move your car just a little bit, you change which reflections are hitting your antenna, and the destructive interference can be increased or reduced.
|
cffbfe16-0905-49ee-8f9f-35aa6d350ae5
|
bt0xna
|
When you exercise your muscles ache afterwards, so how come your heart doesn’t ache after doing cardio?
|
One: it's a different type of muscle. Two: it gets a steady supply of nutrients to repair and replenish itself.
|
e9e2eb50-affd-4bb6-95c4-7f508947ddc1
|
bt0xsp
|
When transferring money from one bank to another digitally, what exactly is being transferred?
|
Its trading IOUs
All your bank account really is, is the bank saying they 'owe' you your balance whenever you'd like it. And of course, you trust them to pay you when you want it.
All this does is shift that. Lets say you transfer $100, the other bank now has an IOU you for $100, and your original bank takes $100 off their IOU to you.
|
26cb639a-f2cb-4f9c-9024-ce663cc6a813
|
bt13fu
|
Is a boy or girl more likely to get an STD?
|
A man is more likely to get an STD, mainly because gay men are the highest risk group for infections and lesbians are the lowest risk group. For heterosexuals the infection risk is higher in women, but only marginally than men.
|
37194580-a18c-42c4-860c-393fd11fe509
|
bt1y6b
|
how did the shape of the heart come to be if it looks so different than an actual heart?
|
Nobody is quite sure, but there is speculation that the symbol comes from the shape of the seed pod of the now extinct silphium plant. This was used in ancient times as, among other things, an aphrodisiac which explains its present usage.
|
291e68ad-6498-41f7-8855-93ca9102d6f4
|
bt22wo
|
When you load a new website how can we trust the website is legitmate? Is the ssl certificate downloaded in browser or perhaps we verify signed certficate with the CA immediately?
|
the SSL certificate is sent by the webserver to you, which is valid only for each connection you make to the webserver (as it is part of the encryption).
You (or your browser) check the legitimacy of that certificate by checking that some trusting agent has signed that certificate.
An attacker could have sent his own (false) SSL certificate, but then it won't be signed by some trusting agent. Unless the attacker has also compromised the trusting agent, in which case your browser (and everyone else in the world) should ignore the signatures from that agency.
|
821b8c9b-7f81-4e4a-918a-ffddff291056
|
bt2a27
|
how do we measure the percentage of water in something?
|
Weigh the item. Heavily dry it, and weigh it again. This gives you how much mass was removed by the process, and then they are compared to find your percentage.
|
4463143c-0630-42a0-b857-b4b27f216668
|
bt2d5s
|
During commercial breaks, why do they sometimes play half a second of one commercial before switching to another?
|
Saw this from a guy who scheduled TV commercials
Every hour of television, there are two local breaks, one minute each. If your local cable company sells that time, a local ad will run. If your local cable company does not sell that time, it defaults to whatever the network chose, usually a specific type of ad called "Direct Response." Sometimes the Networks center and the Cable Company's center are not in synch. Watch FX, it's off by about 5 seconds. Most networks it's no more than 1 second.
|
38766839-da13-4576-acca-f20459af2329
|
bt2gdh
|
Why do you not see flowers almost anywhere in the wild where not purposely planted? Where are roses and tulips etc. actually from that we never see them?
|
Most of what you see were created by people through genetics whether naturally mixed or in a lab. Wild roses and tulips are prolific where they are native, but they aren't that interesting to look at. Forests on the east coast of the USA are largely deciduous, but on the west largely evergreen. Both grow in both places, but historically they naturalized where they are. You likely don't live where roses and tulips are naturalized and native species, and even if you did, they look nothing like what you buy at the store.
|
3f304545-fe3d-42f7-b46a-24b9ca84121b
|
bt356k
|
how and when does one use semicolons?
|
When you want to add a related point to your original statement without starting a new sentence.
E.g.: "Pauline was a record-breaking corn husker; he husked 500 corns in 3 minutes last year."
Or: "You can't drink bleach; your student loans don't cover bleach-drinking."
It includes the same grammatical weight of a period without the phonetic gap between sentences that a period creates.
|
12cbb4ee-dc94-4f77-8443-0a9ebb2bed8f
|
bt3e5q
|
. How does a snowflake maintain symmetry in all of six sections but share no symmetry with other snowflakes?
|
by "careful" practice.
A symmetric snowflake costs less energy to maintain than an asymmetric one. Or in other words, starting from a warm drop, when the molecules wiggle and try a more symmetric shape, they release more energy into the surrounding. if the surrounding is colder than the water/flake they don't get that energy back.
So bit by bit as the snowflake loses energy, it gets more and more symnetric.
|
b8551bbe-7876-4556-aa7b-52fe7125dc65
|
bt3h3t
|
How people move bionic limbs with their thoughts like normal limbs?
|
The advanced prosthetics that work this way are very rare. They use electrodes connected to the nerves that used to control muscles. When they detect electrical signals in the nerves, they move the arm. The user "learns" to control the limb just like how a baby learns to control their limbs. You make random signals and the arm responds randomly. The brain is very good at learning in this sort of situation, where there is visual feedback. It's not as good as when there is sense of self, but it's pretty good.
|
5646af88-2303-4859-8eea-1f2c912b9952
|
bt41pw
|
Why can't we have a universal currency?
|
We can. Just convince the US and the UK to accept the Euro.
Slightly more seriously - a single global currency would be a bad idea. As the EU has found out you get problems when a single member hits recession. The value of the currency falling is an important part of the recovery process as exports from that member look more profitable, creating jobs and boosting the economy.
|
3f1a23af-cc09-4fb2-8b70-be949d492798
|
bt48pd
|
Why is radiation poisoning contagious?
|
Radiation poisoning isn't contagious--but it *does* destroy one's immune system, in severe cases.
The reason they must be kept in isolation is because they'd die from the germs others brought to them.
|
7677c5b8-8da9-405f-9328-d4e075ccf04a
|
bt4dmi
|
How do bionic prosthetics work?
|
It varies a little but essentially a bionic prosthetic is a machine that takes input commands and executes those. Commands like 'bend at the elbow', 'close the fingers' etc. How you give those commands varies but the most common method relies on picking up electrical signals from muscle groups and translating those signals into commands.
Simply put, when you contract a muscle (like flexing your bicep), that creates a detectable electrical signal we can pick up with an electrode. When creating bionic prosthetics we often train the user to use muscles unrelated to the bionic limb to control it. For example, if you contract or flex your pectoral (chest) muscle, your bionic hand will open or close. It takes a bit of practice but since the pectoral muscle doesn't interfere with the normal use of your arm, it's a muscle that's essentially free to do work for grasping.
Another method uses brain waves. It trains a computer to recognise the specific activity pattern in your when you concentrate your thoughts. Let's say I tell you to focus on the mental image of 'dancing giraffes'. That's a pretty unusual thought so I'll likely be able to train a computer to recognise when you're thinking 'dancing giraffes'. If the computer can recognise that brain activity pattern, it can also translate it to a movement of your prosthetic.
Finally, machine learning can also be used to train a prosthetic to work in concert with your body for common motions. For instance, when you walk, there's a very specific series of foot, ankle, lower leg, knee and upper leg motions. Artificial intelligence can be used to make a lower leg prosthetic understand your gait when you walk and automatically cooperate with this series of movements to aid in balance and gait.
In other words, the AI makes the difference between you having a stiff pirate peg leg style prosthetic and a prosthetic that recognises you're walking, jumping, going up or down stairs etc. and making your prosthetic lower leg cooperate accordingly.
If you're interested in this, try watching some Hugh Herr videos. He's a double lower leg amputee scientists who does some of the most cutting edge tech prosthetic limb research in the world. He uses himself as a guinea pig for his leg prosthetics and he's done a lot of TED talks where he literally jumps and dances around the stage demonstrating his work.
|
4c0305ed-a2fc-4434-b2ae-84c102e4c809
|
bt4f2f
|
How do linguists understand ancient/dead languages?
|
For some like Latin while the native populations stopped using it as their primary tongues, thus causing it to be classified as a dead language, specific groups continued to use it. For Latin these groups were the Catholic Church, and Academic Scholars.
For others like Ancient Greek they utilize modern variants to reconstruct how the ancient language functioned.
For those like Egyptian Hieroglyphics they use writings such as the Roseta Stone that have the same information in multiple languages, at least one of which they already know to decipher those that they do not.
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0550829e-0418-48a9-84e4-ec14840f5884
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bt4h9z
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If scabs are intended to protect an open wound from infection, then why do they send a "signal" to the brain that it's itchy? Why would our body create a situation where it's likely to get an infection if we scratch it?
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It's not the scab that is itching actually, it's the skin underneath it; The scab is there originally more to keep you from bleeding, the itching is your skin (which has nerve endings) breaking down so it can repair itself. This process uses digestive enzymes, that piss off the nerve endings, making you itchy.
It's not that the itching is intentional, it's just that it has to happen if the scab can ever go away.
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a51fc764-017c-45d5-acb5-3ee919be2d0a
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bt4itw
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Why does crossing your arms the opposite way feel so strange?
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Purely muscle memory. If you so anything one way for long enough, changing it up feels off. As another example, have you ever tried switching the hands you hold your knife and fork in? You can do it but... it doesn't feel right.
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0c11388f-6bb1-4a31-8a9e-05732cd06901
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bt4t1f
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how a amputee controls a bionic arm.
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There’s electronics that picks up the signals sent to the remainder of the arm and translates this to movement.
When you tell a muscle to contract you send a very weak electric signal. The bionic arm will have EMG sensors that pick up the potential difference between a reference point and the signal source (usually the head of a muscle). Data from multiple sources is used to detect the desired movement.
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17a0644d-40ba-419c-8c4e-88e02b8c5cae
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bt4xek
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How does coffee become decaffeinated? Is it healthy for you, or is the coffee equivalent of diet sodas?
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The method I'm aware of is that they basically wash the beans with liquid Co2, and make "Co2 coffee" with it until they have removed at least half the caffeine. I'm sure there are other methods, but this in particular wouldn't make it toxic or anything. Just weaker since it's been used already.
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bb091c03-4499-4955-8be0-ae5890dadd11
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bt566a
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What is it that allows the UK prime minsters to resign so often? In the US resignations for the presidency almost never happen, but I hear about it a lot in the UK.
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A prime minister style government is different from a presidential style government and it is not just simply a difference in name.
In a presidential style government, you vote for the president ( maybe not not exactly, but close enough) . In the a PM style government you vote for candidates from your constituency to parliment. The majority party in the Parliament, or a majority coalition, choose a prime minister. Although typically, the party leader becomes the Prime Minister and is often the face of party, during elections. Which is why you hear complains in these places that the election is becoming too presidential.
So at any time during the term, the party or coalition may become dissatisfied of the PM, and force him/her to resign, which what happened to May. Or sometimes the PM him/herself might just resigns after he/her royally fucks up, like what happened with Cameron.
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767dbe55-fda6-4d03-bed6-7e0358bfb2a1
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bt5azy
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How does laughing really hard and feeling extremely sad trigger tears when they’re two different emotions?
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There are actually different types of tears!
Basically, your body always tries to stay balanced (homeostasis).
When we have too much of an emotion to an extreme, we begin to cry.
Those tears are different from each other in their chemical makeup. All the signals within our bodies are electrical or chemical (hormones).
When you're too excited/happy and begin to cry, that's the body's way of flushing the excess chemcials out of the body. This way it doesn't build up more and more and helps return the body to its "natural balance."
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93493f95-b40b-4857-b2b2-96d0cee6cfe5
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bt6077
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If hot air rises, then why does it get colder the higher you go? Where does the hot air go?
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The higher you go the less dense the atmosphere becomes. This means there are less molecules which could transfer energy so the overall temperature is less than it would be on earth's surface. Also the molecules in the air lose energy on their way up. Either through radiating it away or colliding with other molecules which spreads the energy across more molecules and thus cooling them down.
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c73ee15f-7bfe-4269-ae3f-67d07d847452
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bt67z3
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How are atoms/molecules able to create a living organism?
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My opinion but probably "we don't really know" is close to the truth. We don't have any issues talking about dead or alive when dealing with animals, insects, plants, bacteria etc. But as you get smaller and smaller and simpler and simpler, this transition from "non living" to "living" isn't as simple. Are viruses alive? Are prions alive?
We know the constituent molecules that make up living organisms. We are also capable of synthesizing them in labs. We can also demonstrate that some of these molecules can be formed naturally in the environment. We even understand how these molecules function in living beings. But ultimately, we are not yet at a point where we can make a "living" organism from scratch.
On another side of things, there is AI (and associated robotics). I believe there are some estimates that our best AI today is not equivalent to that of a cockroach (maybe we're close) At some point, we may have to answer the question of whether we can produce AI that is sentient. We might be closer to AI sentience compared to our ability to build a living organism out of atoms/molecules.
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9971b771-1d76-4dc9-8ba9-297337c7ce55
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bt6fl1
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Why can’t I take a photo with my flash on at museums or historical locations?
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It disturbs other people, and the harsh light can damage historical items such as old fabrics.
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4a230367-a586-4910-9879-04ffe431a4a4
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bt6hgc
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why do high pitched sounds hurt for people who can hear them and not for those who can't?
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High frequency hearing loss occurs when the sensory hearing cells in your cochlea have become damaged or die.
When this occurs there is no longer any feeling.
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a06e64e5-22eb-45e9-b9a1-a224cacd892e
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bt6l0f
|
Why is our hearing dampened while yawning?
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Yawning opens an air canal that pumps air into your ear from inside. (Sneezing, blowing nose, etc does that also).
Changed pressure makes it harder to hear, because ears aren't as sensitive to vibrations due this. Sort of like banging a drum (or any similar surface, really) sounds duller if you press your other palm against it, to block or dampen drum skin from vibrating as much as it normally does. Or for example, try to bang the drum underwater.
Ears are all about pressure.
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2a775024-9e25-46fc-bb01-1495eb4060e0
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bt700b
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If muscle mass = higher metabolism, then why are marathoners known for having a high metabolic rate, but not the bodybuilders?
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Bodybuilders are known for having to eat insane amounts of food. For precisely this reason.
Muscles consume a lot of energy to simply exist. That is why our muscles get smaller if we don’t use them, our body is conserving energy.
But on the other hand marathon runners do incredible amounts of exercise so they also need to eat a lot to ensure they don’t get their energy by breaking down muscle or fat reserves.
Michael Phelps (swimmer) is an extreme example of this. He eats 10,000 calories a day just to maintain his weight.
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350ebff9-9d1f-409c-8353-ae55dd0642fd
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bt70or
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How do river levels rise in feet so quickly when we only get a couple inches of rain?
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When rain falls, it heads downhill and continues moving downhill until there's no downhill left (i.e., it hits the lowest part of its journey) or it gets absorbed into the ground (or evaporates). When the ground is saturated (like after a heavy rain or just a lot of rain over a short period of time), rainwater isn't absorbed into the soil and will just continue to flow downhill. Streams and creeks are typically found in small pockets of downhill flow. These fill quickly and they flow downhill as well, joining other creeks and streams, forming small rivers and then larger rivers. After a hard rain, all that water rushing into all those creeks, streams, small rivers, etc. keeps flowing downward to the larger rivers. In any sizable river system there are thousands of these smaller feeder creeks, streams and rivers, all swollen with rainwater, all flowing to the larger river. All that water causes the terminal river to rise rapidly.
Another way to think about it is to think of the size of a river's drainage basin (the area that feeds into the river). Some are huge, thousands of times larger than the river's actual area. All the rain that falls in a river's watershed eventually joins the river unless it is absorbed into the ground or evaporates. If one inch of rain falls over an area of one acre, that's about 27,000 gallons that now has to flow somewhere. Take the Susquehana River as an example - 464 miles long with a drainage basin of 17,600,000 acres. An inch of rainfall throughout the drainage basin adds nearly 480 billion gallons of water, much of which will make its way to the Susquehana sooner or later. When the ground is saturated, it gets there much sooner, causing the river to rise quickly.
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df7da8f0-8e86-45a1-8558-6259181c5503
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bt7ee7
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why is the tipping culture in the US so different from other parts of the world?
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[Economic Policy Institute ](_URL_0_)
Tipping originated from a hesitation to pay freed slaves the same wages as whites. If I can give you a job but find a way to pay you less based on my perception of your service then it helps to maintain my psychological superiority.
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a3d1cc90-e952-4178-b709-c93e0ddd8380
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bt7eff
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Why does alcohol stop tasting like alcohol when you're drunk?
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Alcohol is a depressant to your nervous system so it dulls all your senses. Similar to if you bump into something while drunk, you don’t feel it until the next day, or why your vision gets blurry while drinking.
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7f99cd37-da51-4e39-a300-5a203ab9204c
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bt7gez
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Why are crabs cooked alive?
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Seafood tends to spoil fast. If the animal is alive up until right before you cook it then you know the meat is not spoiled.
A lot of the bigger ones are killed and cleaned first.
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60d7dc23-2f52-4435-8916-d33dce2d2bcb
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bt7jrf
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How can plants (weeds, grass etc.) push through and break concrete and other hard surfaces from beneath?
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Weeds and grass do not break through concrete, Their seeds fall into cracks already existing and then grow. Tree roots from large trees can push through and break concrete. I am in the process of replacing my garage floor because the root of a 100 year old one has pushed through.
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9c376cd3-0464-4e90-a4eb-4aba03025d5e
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bt7u7k
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Do we really need to get our wisdom teeth removed? And what takes place after your wisdom teeth are removed? Do they just come back?
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Well mine came in sideways and busted through my gums and made it hard to eat/talk. So in my case yes, i needed them removed. There are some people that have them and they come in like normal teeth though.
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9c7c6a32-8803-4159-ac8d-e0e87e564050
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bt7ut0
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Why do most video games only run on Windows and not Mac OS?
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The install base of Mac OS is incredibly small compared to Windows. The developers would have to do a lot more coding in order to make the game run on both operating systems, and that would cost money. The ROI would be far lower. Mac OS also isn't really optimized for gaming, so gamers don't tend to use it.
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3774b989-23ce-4f62-852d-3f280080e76b
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bt85s9
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After the money bills are printed, how do these bills get in circulation? For sure through banks, but what does the bank do? They purchase a certain amount and pay via fund transfer??
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Banks trade older money to the federal government for fresh new hills and then place those in ATMs and local/regional Banks to be distributed to you (consumer). When you buy something at the store with a torn up or old bill, the store takes money to bank to be deposited and bank does an exchange with the Federal government. Rinse and repeat.
The Government literally shreds and burns the money and if you don't tour at the treasury musem in Washington DC, you can get a bag of old money (shredded of course)
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4df49a96-0ee9-4713-b723-05807be3eadb
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bt8awe
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how does your body determine which fat to burn?
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Primarily genetics. So if you hear “do crunches to target that pesky stomach fat” etc... it’s a lie. You can’t burn specific fat areas with particular exercises. Your genes tel your body where to put fat and where to take it from. Men primarily store a lot of fat in their abdomen, around their organs (visceral fat) and women tend store fat around their hips, butt, and thighs (subcutaneous fat).
Your body will also always burn fat that isn’t as important. E.g. fat on your thighs vs. fat that line and protect your organs. Your body will always prefer to use the thigh fat as opposed to the protective layers of fat that insulate and cushion your organs.
So 1. Necessity 2. Genetics.
Edit: important to note, as someone did below as well, that visceral fat is very bad. The majority of people have far too much visceral fat (including myself 😬 goddamn beer) and some can be viscerally obese (there are diagnostic criteria but researchers are still debating how effective some are). While some fat is needed for protecting organs, it’s a relatively small amount when compared to what the average person actually has in that area.
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0171a67a-38f8-471f-8ce3-fe20fadaadf9
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bt8c2l
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How does building muscle work?
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Your muscles are made of 2 types of fibers: fast twitch and slow twitch. Working out pulls some of the fibers apart a little, which makes your body add more fibers to repair them. More fiber means more strength or endurance.
Low weight high reps is slow twitch fiber. They don’t fatigue as fast, but aren’t as strong. It builds endurance. High weight low reps is fast twitch fiber. They fatigue much faster. It builds strength.
If your workout is running, then long distance is slow twitch, and sprinting is fast twitch.
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de50e059-84c4-40b1-a693-1520a6ff0fc0
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bt8czn
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how come TV shows cover up brand names on products (like food or toiletry packaging) but YouTubers can show brands and review them all day long?
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Tv shows that do that don't get paid by companies. So they don't show any names.
But there are also clear cases when TV shows are paid to do commercials.
_URL_0_
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5ba70daa-049d-438e-b742-1a202ce24f95
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bt8j2r
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how does education system works? and what does it prepare us for?
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There are many hypotheses about the best ways to teach children (inquiry-based learning being the one I use in my work) and the best things to prepare them for. This varies across not only the world, but even in the US public school system. So your question isn't really specific enough to answer in a meaningful way.
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f4603109-0301-477a-b6e3-7d62e226321b
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bt93v3
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Why specifically does the Northern part of Africa have desert land? I’m assuming it’s on the same geographical level as other countries that have no desert at all?
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Climate is much more than just latitude
Things like altitude, geography, air currents, water currents, all of that factors in.
England for example is at the same latitude as parts of Canada that are covered in snow much of the year, yet England has a much milder climate. This is because the north Atlantic ocean current drives warm water and subsequently warm air right to the British isles.
As for the Sahara it is believed that northern Africa regularly went through periods of humidity where it rained a lot and there were lakes and rivers and forests full of life, and periods where the air was dry and all the water dried up and everything died. This was caused by small changes in the planets tilt on its axis. Then at some point some factor changed in this sensitive balance that threw the whole system out of whack.
Current thinking is that this coincides with the spread of humans and agriculture across africa. As northern africa was transitioning from a humid period to a dry period humans transitioned from hunter-gatherer to domesticated animals and farming in order to survive which could have lead to over grazing, over farming and destruction of vegetation. This vegetation would have been needed to provide the moisture in the air to trigger a new humid phase when the time came. Without it the next humid phase was never triggered and the system spiralled out of control leading to the eventual creation of the Sahara desert.
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44c59aaa-9f76-494c-8094-63210fff96b6
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bt963t
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Can a drug itself cause the disease it is meant to cure?
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The chemotherapy agents used to treat cancer can, themselves, give rise to other cancers. So... yes.
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36456ef6-8c1f-4981-81ad-942ab748da5f
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bt9kb0
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Why do flatscreen/LCD monitors display random colours and bizzare shapes or patterns upon being cracked?
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Like others have mentioned, it can be the glass breaking and causing rainbows (from diffraction). You asked specially about Liquid Crystal Displays, the liquid can flow around when the display is (more accurately, the pixels are) broken.
“Flatscreen” is a physical shape and not a method of building a display - these can have many methods. LCD is one type, the others will have different reasons for weird behaviors when they break.
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8502e188-1546-48c4-b3c8-35cbdf679428
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bt9oal
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When a baby/infant recieves am organ transplant, does the organ grow in size with them? Since they're babies, would the organ become "theirs" or might they need another transplant in the future like adults who recieve transplants?
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The organs will grow but sometimes the recipient will outgrow the organ, especially kiddos which will require a new transplant. This is often the case for hearts.
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68c1ba62-9daf-46b9-9456-b953ee72d53e
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bt9pxo
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What’s to stop a bank from just making up money on their computer systems?
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They get audited regularly and any discrepancies carry large penalties and potential criminal charges.
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8a9e98b9-245a-4fa2-8714-7ba0ab89066f
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bt9t1f
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How do bugs’ legs stick and unstick to everything?
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This is going to sound a bit silly but it is true. Insects and other “bugs” have small claws on the ends of their legs. They are light enough that those claws holding on to the tiniest imperfection in the surface is enough to hold them up.
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fea2f150-28f1-42b2-a4bc-a9a3b7bfe172
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bta0pp
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Can anyone explain the phenomenon where people will have similar experiences while hallucinating? Whether it’s sleep paralysis or DMT, it seems strange that people across the world would see the same figures or geometrical patterns.
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Well aspecially for the dmt and geometrical patterns, I guess one point is, that we hear a lot of story's about those things and our brain can somehow relate, because it is "familiar", as we heard or saw it quite often before.
An other options is, our brains are build pretty similar, even so we are all individuals, many habits are the same, maybe coming from instincts and others, passed through ages, the chemical build up in our brains and what not. therefore we get quite equal experiences, because our brains react in somewhat same ways.
These are all my own theories and far away from science as I looked nothing up for that nor am I some specialist in any form!
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db806cd2-1949-4eda-9440-77fc557edbdb
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bta7c5
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Vocal Ranges
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The notes D and C are the pitches he can sing. The number is the octave he can sing it in. For example if it were D2 and C2 he would only be able to sing two notes. There are 7 notes in each octave so he can sing a range D2-C7 of 34 notes.
Edit: math.
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49597d03-3394-4245-9000-dddb0d98ccfc
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btab77
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Do we really know why astronomical objects rotate and orbit? And, why they are doing that in a certain direction?
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When the gas clouds that the solar system was formed from started to collapse if not everything directly move to the center stuff star to orbit the gravitational center. The result is that the stuff will have a angular momentum that is preserved and start and planets that are formed will continue to rotate because. The angular momentum is one thing in nature that is preserved.
& #x200B;
Because of collision and gravity the stuff that start to obit the center start to get collected in a single plane and it is in this plane that the planets are formed. So all planets have the same motion because the way formed from the same orbiting disc around the sun.
The direction the disc has relative to the rest of the milky way is quite random and is because the gas clouds was not uniform. Planets around other star orbit on different planes.
& #x200B;
So stars in a single star system have the approximate same orbital plane but orbital planes of different star system are not aligned the same way.
& #x200B;
The name east is based on words for a rising sun, dawn. If earth rotated the other direction that would likely be called east because of the history of the world. Prograde is just the same direction as the rotation of the body it orbit. Non for the names is absolute but relative to the motion.
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9bb619c7-7f2f-45c5-a54a-f91a68c7ac94
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btabl9
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How do videos switch between low and high qualities so seamlessly?
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Most site do not serve whole video file.
Video is split on many chunks and when need different resolution the new chunk is loaded.
you can read about HLS / DASH for streaming
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84845484-daa9-4c4b-baa2-424402e50544
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btahv0
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Why our nose runs when we eat spicy food
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Your body is perceiving the spicy food as a threat and it is using mucus production to flush the offending material out of the system.
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befff8c4-513f-4d95-a924-e8c07ebd7cb4
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btak8k
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Why does car window tinting only work one way, and maybe similarly, how do one-way mirrors work?
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Both tinting and mirroring work both ways. The only difference is that if there is a significant difference in illumination in one side against the other the transmitted image intensity outweighs the reflected or vice versa.
If you are outside on a sunny day, it's very hard to see into an unlit room through an ordinary glass window, but it's crazy to see out. At night with the room lights on you can see in but people I side don't see much out of the window.
In a car with tinted windows, the illumination inside is usually light coming in from outside through the tint. So things inside are not strongly illuminated and are dimmer than reflections in the windows of things outside.
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316fd46d-1743-4ebc-9fa4-1b45d5170ea0
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btax3e
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Why is it that while driving a car you sometimes hear the radio at a wrong pitch?
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If you're talking about FM radio as opposed to playback from your phone, I think I can help. So if you have a good enough ear to realize that a song is a half step high, you'll know that if you have two identical song files or tapes and one is played slightly faster/ pitched up higher than the other, it will be perceived as warmer, brighter, and more energetic. Radio stations exploit this effect. If there are two radio stations playing identical songs, one radio station could speed up playback to pitch the song up slightly. This would result in the station sounding more energetic and brighter to the listening population along with more inviting and maybe warmer depending on individual perception. This is in the same way that a song at A440 will sound less warm than a song with A tuned a little higher.
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0845add7-e543-4418-8769-a2d4d37dafe3
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btazvl
|
How is that a choir can sing someone else's music, but a youtuber can't play certain music in their videos?
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The right to perform or record a song written by someone else, the right to play a recording of a song in public, and the right to "sync" (the legal term) a song recording to video or film are all treated separately legally.
For the first one, you have to pay the people who own the publishing rights to the actual *song* (lyrics and/or melody). Usually a choir would buy the official sheet music to a song. Also, choirs often perform traditional songs or classical music that isnt covered by copyright.
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9992d185-262b-4890-8bfc-366addb5bfa4
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btb4qb
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What happens to an oil field after the oil is pumped out? Does it just leave a void/cavern? Isn't it today to leave that because it could collapse?
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Oil isn't in a big cavern underground. It's seeped into the rock, and when a hole is drilled through the pressure of the Earth compressing the rock squeezes the oil out. So when there's no oil left, there's still plenty of rock down there.
In some formations depleting the oil/gas can cause some ground subsidence, but usually nothing dangerous.
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91ed3783-e0c9-40ea-a8c9-70fbd553472b
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btb7l5
|
What's the main difference between DNA and RNA?
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Well, RNA is just one spiral instead of a double helix, and is composed of slightly different amines that analog similarly to the ones in DNA (CGAU vs CGAT). RNA contains Uracil rather than Thymine.
The other major difference is that there’s one more oxygen molecule bonded into a hydroxyl group (a hydrogen molecule stuck to an oxygen molecule) in ribose than there is in deoxyribose (hence de-oxy ribose) and ribose is the R in RNA while deoxyribose is the D in DNA.
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36feed28-ec34-451f-a307-6aa6d8d8a31a
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btb96z
|
Laminar Flow
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It just means that vast majority of the fluid in a flow is moving in the same direction. It will generally happen in short distances, with lower velocities, and smaller pipe diameters. Those factors contribute to what is called a Reynolds number, assuming the isn't an obsticle top obstruct flow. Lower values will give more laminar flow.
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aa21b784-f4cc-425c-b9e0-f9f5efe3c6b2
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btbah0
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How do people organize sound, form a word out of it; and give that word a specific meaning?
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Same way we give anything meaning: enough people just agree that this sounds means that shit.
Do you think cavemen thought diamonds are THE thing to get for that fetching cavegirl over yonder? No. At some point a bunch of people decided getting a girl a ring means something, a ring with a diamond means even more.
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d1903aaa-c315-461d-ad48-4b5c6ae0711d
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btbdjg
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what makes a file format better than other?(speed, file size, etc) for example the new file format of the oneplus 7 pro
|
What new file format are you talking about? A search for "new file format oneplus 7 pro" result in not relevant hits. So can you provide a link to what you are referring to.
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8f3cc44f-e010-4500-b960-1fdc1facfb0a
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btbfjf
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How did we manage to map the brain and figure out what each part controls?
|
Most of the historical information on the function of specific parts of the brain was first discovered by looking at people who had lost those parts of their brain (due to a stroke, physical injury, or whatever else) and seeing what functionality they lost. Someone who lost their Broca's area wasn't able to speak, which means that the Broca's area is used for speech, or someone with a frontal lobe injury had reduced emotions - that kind of thing.
Since then, directly stimulating part of the brain with physical contact, electricity, very high-power electromagnets, etc. and observing the results has also been used - basically the scientific version of "poke it with a stick and see what twitches". Obviously this is done on animal models more than on humans.
Most recently, we can use radiographic techniques like fMRI and PET scans to see the areas of the brain with increased blood flow during specific activities - that's where the "brain activity scans" you might have seen around come from.
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368fb1d6-c585-4efb-a73e-9fd15d00e769
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btbggw
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What is a step, 1/2 step 1/4 step 1/6 step etc, in music, relating to rhythm/time signatures?
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I think step is the wrong word for your question. Steps usually refer to changing pitches. For rhythm, we're looking at notes and rests.
& #x200B;
looking at 4/4 time which is by far the most common. 4/4 means there are 4 beats per measure, and the quarter note = 1 beat. So 4 quarter notes = 1 full measure.
I like [this image as a demonstration.](_URL_0_)
Each line of this pyramid is equal to 4 beats total, which is equal to 1 measure in 4/4 time.
& #x200B;
Twinkle twinkle is a good song to test this out on. the first line is two measures long. each syllable gets 1 beat (or one quarter note) {measure} **word** (note length)
& #x200B;
{ **Twink** (1/4) **Kle** (1/4) **Twink**(1/4) **Kle**(1/4)} ***1/4 +1/4 + 1/4 + 1/4 = 1 full measure***
{**Lit**(1/4) **Tle** (1/4) **Star**(1/2)} ***1/4 + 1/4 + 1/2 = 1 full measure***
& #x200B;
So the type of note - regardless of pitch - tells you how long to hold it, or put another way, how much of the measure the note equals.
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5dc79fad-b1b7-437b-8870-4ce6a274bc7d
|
btbwhu
|
If trees can turn CO2 in oxygen why can't they solve the climatechange-problem
|
I am no expert on this, but trees do exactly that. There are simply not enough trees compared to the amount of CO2 we are producing.
|
0954f0ec-d32f-4d03-a33f-ddcd6c1dc396
|
btbx92
|
Why can eyes heal so quickly in comparison to other parts of the body?
|
The scratches are not the same. The scratch 'in' your eye is merely a scratch on the cornea, the outer layer. It's like getting a light scratch on your skin that you can't even feel (like just a white stripe). Those heal very fast, but the scratch on your skin that bothers you is through two or more layers, often drawing a bit of blood too, so that's harder to repair and takes longer.
|
ecbf0053-3ece-4865-a109-39633789c3c9
|
btc2kp
|
What constitutes serving size/how is the serving size chosen for certain foods?
|
Serving sizes are the arbitrary division of a food based on how much they expect you to eat or drink in one sitting.
For example, many drinks will based it on 8 or 12 oz, which is a serving of water. But some have begun to realize that you aren't sharing a 20oz of Pepsi, and put the values for the whole bottle.
By giving the nutritional values based on a specific amount, the consumer can technically make a more informed decision on their eating habits. Though, packaging can still be deceiving.
For example, Pop-Tarts are given with a single pastry as the serving size, but they're packaged in pairs. This makes it seem like a healthier option than other snacks, because the values are halved compared to what you are likely eating.
|
50fa98e1-129d-4652-94aa-10497b7afaba
|
btc87a
|
How a phone battery charges?
|
The same way all batteries charge: electrons are taken out of one side, transferred through some wire and put back in the other side. When you use the battery the electrons go back to where they started.
I have no idea what the second bit of your question meant
|
93461f59-fa78-4261-ae28-419949949090
|
btcdjk
|
How does Earth's magnetic field come from its metallic molten outer core if metals are great charge conductors and thence tend to be electrically neutral?
|
u/JohnnyJordaan’s answer is essentially correct, and more Eli5 friendly than I can manage when I try to fill some details. This is the best I can do:
We can’t think of how that metal would behave at the surface here, because the outer core (where Earth’s magnetic field is essentially generated) is molten and so it’s not so important that it is electrically neutral (as it would be, even fluidised there are enough localised electrons to balance out a charge in the big picture).
Like I say, that’s not important because that the charge thing creating aligned spin of electrons is what produces a ferromagnetic effect. Ferromagnets are [not possible above certain temperatures](_URL_0_) and the outer core is waaaay above that temperature.
So what’s going on?
First, "neutral" is only a property when viewing the whole system at large. When looking at tiny scales, any particular temperature will have random fluctuations and produce micro-pockets of positive and negative charges in any conductor, whether it's a copper wire or a giant ball of molten iron.
We know that a moving electric charge creates a magnetic field. So if you allow these microscopic pockets to move relative to each other, they can generate magnetic fields which will move oppositely-charged pockets in the opposite direction. In turn, those oppositely-charged pockets will produce magnetic fields that move still more charges around, each time reinforcing the initial motion.
At some point, this feedback effect will produce large numbers of positive charges moving in one direction and large numbers of negative charges moving in the opposite direction, giving you a large-scale current in a neutral conductor, all because you allowed charge fluctuations to move relative to each other. (This phenomenon is closely related to turbulence in non-electromagnetic fluid dynamics, which also gives large scale flow effects from microscopic fluctuations.)
A key part to this self-reinforcing current being setup like this is the ability for those tiniest of charge fluctuations to move past eachother. The outer core is molten metal, so it’s mechanically supported, but able to flow, just what’s necessary. Conversely, electrically conductive solids don’t let the microfluctautions within move relative to eachother, which is why you won’t generate a magnetic field by waving a piece of copper wire around.
|
bf0af2a0-031e-4f21-9893-b4445d9d833d
|
btcdvc
|
If the point at which water changes states from liquid to gas is 100°C, how then, when you spill water on a table or elsewhere, does it eventually (and relatively quickly) become evaporated in ~21°C temperatures?
|
So boiling happens at points in the water where the water reaches 100C and has enough energy to change state. Evaporation happens at the surface of a volume of water. Random movement of the water molecules occasionally impart enough energy into a molecule of water that it can escape the bonds of the water around it and move into the air. Water evaporates more slowly in humid weather because the partial pressure of water in the air is higher while boiling will happen regardless of humidity.
|
3470d171-061e-422f-a7fb-198bacaabd05
|
btciox
|
Why and how can energy become matter and vice verse according to Einstein’s theories?
|
The definition of energy according to google is
> the property of matter and radiation which is manifest as a capacity to perform work (such as causing motion or the interaction of molecules).
& #x200B;
Mass and energy is the same and if you could measure the mass of a object that start to move excavate enough you would see that that mass increases when the speed increases. But in everyday situation the mass increase is so small that you can measure it.
But for a object that traveled at 86% the speed of light the mice would be twice the mass at rest. As long as you do not have whole percentage of the speed of light the mass increase is low. You increases the mass by 0.1% at 4% the speed of light.
The fastest object in space created by humans will be the Parker Solar Probe that in 2025 will travel at 690,000 km/h (430,000 mph), or 0.064% the speed of light. So for large stuff that is not individual particle the mass increase from the kinetic energy is negligible
& #x200B;
& #x200B;
Heat is thermal energy, a moving object has kinetic energy. But you also have potential energi like in a gravity field when you can move it, that is what is extracted in a hydroelectrically power plant. You have electric and magnetic potential energy.
Electricity is moment of electrons but the energy is form the difference in voltage and you can have that without any moving electrons.
The bounds between atoms in a chemical compound store chemical energy that can be released when it react with other chemical and that is how you power your body. If you would measure the exact mass of sugar and oxygen that react and become carbon dioxide and water you would notice that the mass is not exactly the same but have been reduced. That missing mass is the chemical energy that is released.
& #x200B;
For chemical reaction the difference is small compared to the total mass but when you star to look at nuclear reaction like uranium fission or hydrogen fission the mass difference is noticeable
For example Deuterium has a mass of 2.013553212745 u and litium-6 has a mass of 6.0151228874u and when the fission two Helium-4 is produced with a mass of 4.002602 u
2.013553212745+6.0151228874= 8.02867610014
2\*4.002602=8.005204
So the you have lost 8.02867610014 -8.005204= 0.02347210014 u of mass. That is a mass loss of 0.3%
The atomic mass unit u can be converted with the e=mc\^2 formula if you convert the units and you would can get the energy of the fission. The common units for energy on this scale is electron volt and 1u= 931 494 102 eV
So 0.02347210014 u is 0.02347210014 \* 931 494 102 =21 864 122 or approximate 22 million electron volt and that is also the stated energy released on Wikipedia for the reaction.
& #x200B;
So all energy is mass and if you could measure the the mass of a object when you heated it up the mass would increase. That always happen but in most cases that the change in mass is not relevant in any way because it is so small compared to the total mass. But if stuff move at speed that close to the speed of light or if you look at nuclear reaction you will see that mass increases and decreases. But at normal human scale it is to small to notice.
|
fd19840c-2d6b-42d5-b9b9-fca637f41d81
|
btclu0
|
How do you measure the volume of a sound accurately if the perceived volume changes with distance?
|
It depends on the purpose of the measurement. For large theaters and auditoriums it is going to be specified at the middle of the theater or a little further back. For police enforcing noise ordinances it will be defined by law. For appliance/power tool safety it is going to be less than a meter (3 feet). In general, the distance depends on where the people will be.
|
7fe92316-b060-42c0-a354-64ab1a61f12b
|
btd2oo
|
Why do foreign plant and animal species only become invasive in their new habitats?
|
They evolved in a given habitat in conjunction with other species that kept them in check. For example, rabbits have natural predators in Europe. Predator and prey evolved together which ultimately kept their population balanced. More predators caused rabbits to evolve to be more fertile so that they can reproduce quickly. But their numbers are kept limited by the predators, whose population increased as their prey species of rabbits increased. Then you go and release rabbits in Australia, which doesn’t have a significant predator species to eat the rabbits, so they breed outrageously fast and become a plague in Australia.
|
5a97fdbc-17ed-40e7-a6fb-a7bde24924a7
|
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