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ELI5: Difference between LED, AMOLED, LCD, and Retina Display? | So these are terms that refer to some fundamentally different things. I'll throw a few other terms in the mix that will hopefully clarify things:
###Display Technology
* Cathode ray tube (CRT) where an electron beam is used to excite colored phosphors on the inside of a glass screen. You may have heard it referred to as a "tube TV". This is pretty old stuff, and is the earliest display technology for TVs.
* Plasma displays, where a gas inside each pixel is made to glow. This is now pretty outdated, but still way newer than CRTs. It was especially common back when LCD TVs were new, and lower quality than they are today.
* LCD (liquid crystal display). This is the most common type of display tech for televisions. There are three different colors of pixels (red, green, and blue) that can be made more or less opaque to let through light being created by a backlight behind the screen. The combinations of red, green, and blue can be used to form millions of different colors.
* AMOLED (active matrix organic light emitting diode). Each pixel is made of of individual little lights that don't need a backlight. This is newer, and is being used in a lot of newer phones, but is still very expensive for large TVs.
###Backlight technology
Note that backlights are only needed for LCD displays
* Cold cathode. This uses a light similar to the overhead fluorescent lights used in stores and office buildings.
* LED. This uses LEDs (light emitting diodes) to provide the backlight. Newer TVs will have hundreds of individual LEDs to provide even lighting and the ability to dim different sections of the screen to provide better contrast.
###Other stuff
* Retina Display. This is just a fancy Apple buzzword for having lots of pixels that are really tiny, so you can't see the individual pixels on the screen even when you look pretty closely. | 7,897 | 15,018 |
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What did Albert Camus mean when he said "Morality, when formal, devours."? | Title\^ | There are some quotes which could help to elucidate this further. One (from his Notebook) is:
"Those who prefer their principles over their happiness, they refuse to be happy outside the conditions they seem to have attached to their happiness."
In another place (can't find it at the moment) he writes that in most occasions you don't need principles because just being merciful is enough. | 112 | 190 |
[GOT] Instead of Trant, if Joffrey had commanded Ser Barristan Selmy to tear Sansa's clothes and hit her, how would the situation have played out? | Tl, dr: Selmy's resignation delays but does not prevent Sansa's beating
He's a professional with professional integrity; of course he'd refuse. His "resignation" would play out similarly, under less public circumstances. Sansa would probably avoid a beating on account of the Kingsguard being predisposed with Selmy's resignation... this time, but Joffrey would probably make up for it later, and with interest. | 54 | 41 |
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ELI5: What does it mean when a state makes reservations, declarations or understandings when it ratifies a treaty? | I was reading on how the US ratified the Convention on the Prevention and Punishment of Crime of Genocide while making two reservations, five understandings and one declaration. Can anyone explain what does it mean by reservation, understanding and declaration during ratification of a treaty, etc.? Thank you! | These are all basically stipulations on how the state will follow the treaty it has ratified. Different treaties will have different rules on how such tools should be treated, but such stipulations are usually respected.
Reservations are the state modifying the treaty, and their obligations under it. They can be a simple: "We aren't accepting this bit and that bit" or something else. There are usually limitations to what can and can not be reserved from--usually that the reservation can not be "incompatible with the object and purpose of the treaty"--and the US has been roundly criticised for its reservations under the Genocide Convention.
Declarations and understandings are basically statements of how the state will interpret the treaty. The state basically says that as to its understanding, this provision of the treaty means [X].
The document you'd want to consult when interpreting treaties is the Vienna Convention on the Law of Treaties, which is--yes--the treaty on treaties. The Vienna Convention has lots of rules on how treaties should be interpreted, and--although many states have not ratified it--it is widely respected, and often turned to. | 21 | 158 |
Is there such a thing as a mathematical discontinuity in nature? | I know that due to the existence of vacuums or near vacuums, material discontinuities can exist, but can a mathematical discontinuity exist as an observable, physical manifestation? One potential example I can imagine would be the singularity of a black hole, which is a 4-dimensional asymptote as gravitational pull approaches infinity, but this is purely speculative since current methods have no way of proving the theory. | One example where discontinuities pop up in nature is phase transitions. Depending on the specific phase transition you're studying, you might find that things like the entropy, density, heat capacity, etc. are discontinuous across the transition. | 21 | 15 |
What's the difference between Social Psychology & Sociology? | Thank you! | Generally speaking, social psychology seeks to study the behavior of individuals within groups, while sociology seeks to understand the behavior and development of large groups and societies as a whole. | 73 | 29 |
ELI5: Why is it so important to print the name of the country that a product is produced in? | I see "made in _____" everywhere and I don't see the impact of it. | Country of origin standards are important for determining how much tax should be charged on the item when it passes through customs. Requiring the tags is also politically popular with organizations encouraging people to support a local economy. | 40 | 61 |
How does dye stick to a fabric so hard that it hardly comes off even with modern detergents? | For most fabric. The dye is first added then fixed with special chemicals. The details vary a lot by the colour and chemistry but often the fixing agent activates at very high temperatures that won’t happen in a normal wash. You can bleach many fabrics by boiling them in running water.
Polyester is different. It doesn’t absorb liquid under normal conditions so it’s typically bulk dyed. The polyester yarn is made with coloured plastic pellets so the fabric itself is coloured. | 2,321 | 5,083 |
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ELI5: What happens when our immune system makes us ”immune” to a disease. And how does it do it? | The Immune System is incredibly complex, so there really is no ELI5 answer, but in essence you have special immune cells that are designed to recognize foreign/non-native molecules called "antigens". When these antigens are found, the immune cells latch on to the foreign cells and destroy them while simultaneously "remembering" the distinct characteristics of the antigen that it was exposed to so that when/if it sees it again, or another very similar antigen, the immune cells can kill it that much more easily. This ability for the immune system to "learn" is its greatest strength and is now being used to harness the same power to fight endemic genetic diseases like cancer. In fact, the most recent Noble Prize for medicine/physiology was given for this discovery. Former US President Jimmy Carter is probably the most famous patient to have used this immunoglobulin therapy to treat the melanoma which had spread to his brain. | 10 | 21 |
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Why do elements need 2 or 8 electrons in their outer shell for it to be full? What makes these numbers so special? | Does the fact that they are both powers of two affect this phenomenon in any way? | This has everything to do with quantum numbers. In general the shrodinger wave equation describes all the ways electrons can interact with an atom. Each of these different ways is associated with a different set of quantum numbers. If you're asking what is stable you're simply adding electrons to an atom in order of lowest energy and keeping track of how adding each additional electron affects the overall energy of the atom.
The way this works out is for non transition metals you have two orbitals S (sphere like) and p (dumbbell like) . The p orbital has 3 orientation that solve Schrodinger's equation (x y z). The final piece of the puzzle is that each one of these four orbitals can hold two electrons (spin up and spin down). It turns out that when you have both spin up and spin down electrons an orbital becomes much more stable. Therefor you either have two electrons and a full S orbital which is stable. Or you need 6 more for 8 to get a full P orbital.
Of course this is a general rule and for many elements the stability might be different. ( The transition metals for example are very ruled by the D orbitals and can shuttle electrons from S orbitals to fill D). | 18 | 22 |
ELI5:The difference between an symphony, concerto, sonata, and waltz etc and so on. | /r/classicalmusic will be happy to help further and provide some good examples.
A symphony is a large work, commonly four movements (sections) long. A series of any movements for any instrument is called a suite. NB there is a pause between movements which should never have applause!
A concerto is a work for a soloist backed by an ensemble like a symphony orchestra or string quartet. Violin and piano are popular solo instruments to write for, and therefore to learn. Choir concertos are known as cantatas, when the words are dramatic like in a play its an opera.
A sonata is also often four movements, though for any single instrument. The first movement must have a specific structure to qualify. Sonatas are very typical solo material aside from shorter individual pieces.
A waltz is a style of music rather than a type of musical work, so it can be composed for anything. It is a 'three-time' dance with characteristic 1 Strong-2 weak-3 weak or "Oompahpah" bass, common in the 1800s Romantic Era. | 48 | 83 |
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Which philosopher would you consider the most difficult to understand? | I usually hear that it's Sartre or Schopenhauer. | I'd say that of the ones you absolutely must read and take seriously if you're a philosopher, Kant is the most difficult by far. Just out of a long list of philosophers, I'd say Hegel and Heidegger. As a group, I'd say continental philosophers are extremely difficult to understand. In the analytic tradition, Wittgenstein might be the toughest. | 15 | 15 |
Is it feasible to write a program to count the number of bees on a small frame? | Just started a job where this pops up often enough. I have a little bit of experience (basic classes, haven't done any large scale projects) with c++, python, Matlab (kinda), and Java.
The frames would look a lot like [this](https://i.imgur.com/7BL6hM4.jpg), though making the background black or white wouldn't be too difficult, and i can get decently high resolution pictures)
Is it worth it to try and write a program like this? | How precise do you need the count to bee? If the approximation is good enough, you could use the lightness/darkness of the picture as a proxy for the count via a simple model (linear or otherwise - plot actual # of bees against the %lightness or darkness of the picture, fit an equation to the resulting curve). That would be a lot simpler than object recognition. | 14 | 17 |
ELI5: How does America benefit from spending so much on military rather than spending more on infrastructure, science, education and foreign aid? | Military indirectly influences/contributes to a lot of advancements in the private sector. It greatly sped up the development of the internet, created GPS, vehicle automation is making it's way to consumer cars, cell phones, Jeeps spawned a whole new market of 4x4 vehicles.
I would prefer the government to spend less on military but the knowledge gained from R&D can be quite useful. | 24 | 16 |
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Eli5 Why can’t something be theoretically be faster than light? Why is that considered the absolute speed limit when we don’t even know what’s out there or what could theoretically be faster? | There probably isn't an ELI5 or even ELIPhD answer to this question. Nobody know why our universe is set up this way. What we do know is what we have observed. You can make very small things like say a proton go really really close to the speed of light. But what we observe when we try to push those things faster is that the more "push" you give them, the less boost you get. You push twice as hard and now its only going a tiny bit faster. you push a hundred times harder and now its only going an even tinier bit faster. Pretty soon you are using all the pushing force in the world. Then you get another surprise, the little proton suddenly seems to act like it's gotten really heavy. And the faster you push it, the heaiver it seems to get. Imagine if you stepped on your gas pedal in a car and the car got twice as heavy!
Basically the rules for our universe say that if you are an object, a "thing" you can't ever go at the speed of light. You might get pretty close. But it takes more and more energy and at some point the amount of energy it takes becomes greater than all the energy in the universe. | 1,704 | 1,237 |
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ELI5: How do zip files compress information and file sizes while still containing all the information? | Image if you had a long paragraph and then try to find all the repeated word or phrases. For each repeated word or phrase, you replace the word or phrase with a lookup. Then you only need to write the repeated word or phrase once and from then on every spot you would write the shorter lookup. This is how files are zipped.
Example
1 - word or phrase
2 - repeated
3 - lookup
4 - you
5 - then
6 - write
7 - and
8 - the
Image if 4 had a long paragraph 7 5 try to find all 8 2 1s. For each 2 1, 4 replace 8 1 with a 3. Then 4 only need to 6 8 2 1 once 7 from 5 on every spot 4 would 6 8 shorter 3. This is how files are zipped. | 8,584 | 10,813 |
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ELI5: Common Core math? | I grew up and went to school in the era before Common Core math, can somebody explain to me why they are teaching math this way now and hell it even makes any kind of sense? | In the past, the focus of math instruction was on calculating ("doing math"). This was especially important in the era before ubiquitous technology with a calculator in everyone's pocket. It also meant that being taught one way to perform a calculation was enough, such as the traditional way to multiply two multi-digit numbers.
But the catch was that there was one method for every topic, and those methods didn't connect well across the years. Learning how to multiply numbers in 3rd grade and learning how to, say, multiply two polynomials in 11th grade were taught using completely different methods, even though the underlying structure is actually the same. As you can imagine, this led to students feeling overwhelmed trying to remember dozens of different math techniques separately instead of understanding the structures they shared in common, like trying to memorize the spelling of a word without knowing how it's pronounced.
The Common Core State Standards are an attempt to do two things: (1) Teach multiple ways of performing early math tasks, to both increase learning for students across many different learning preferences and to stress underlying themes and structures instead of just processes. And (2) to emphasize what mathematical thinking is really about - how to think about mathematics and not just how to do it - by adding what are called "standards of mathematical practice" to the content. These include things like "I know how to look for and make use of repeated structures and patterns" which is a skill that leads to math success in every year of school whether it's addition or simplifying fractions or graphing parabolas.
The real catch is that many math *teachers* weren't educated to think this deeply about math, especially elementary school teachers who usually don't get degrees in math. So if they're anxious about math to begin with and barely comfortable teaching basic processes, trying to teach for deep understanding using multiple approaches that they never practiced themselves in school is a real, difficult challenge (and the reason for so many frustrated and derisive Facebook memes posted by teachers and parents!). | 127 | 71 |
[Doctor Who] So how do fixed points in time work? | Throughout the Doctor Who show (haven’t seen classic) they talk about how certain points in time are fixed and can’t be changed whereas the rest of time “can be rewritten.” But that doesn’t make sense at all. Numerous time the doctor prevents the end of the world. But later fixed points in time required humans. So how can they be fixed? Or is the human race not actually in danger?
Edit: I understand I shouldn’t apply logic to doctor who but I want an explanation dammit. Haha | It's the concept that certain events in time *must* happen so that some form of continuity exists. Let's say that such an event is Robert Q. Higgins dying in 2054. That means that the Doctor can go visit Mr. Higgins, alter what he had for breakfast on his final day, take him out for a tour of the Andromeda Galaxy, and get his help in defeating the Daleks during the American Civil War. It also means that Mr. Higgins *must,* at some point, return to 2054 and die.
In a way, you can think of it like a typical computer RPG. You can give your character and your party all the custom gear you want, have them help/hurt/kill whichever NPCs they choose to, steal anything that isn't nailed down, etc. However, in the end, they have to kill the big-bad and there's nothing you can do to change that without just turning the game off. | 41 | 52 |
ELI5: Why do you have to put in your debit pin in person, but not online? | The Idea of a PIN as a cardholder verification method relies on the two sets of data involved (card number and PIN) not being transmitted in the same way.
For online websites, it's easier to use some other form of verifying the cardholder, such as with a billing address, CVC2 code, or two factor authentication, than to create some standardized way of transmitting pins in a secure fashion separate from the card number. | 11 | 16 |
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Direction for a nihilist. | Hey everyone. As a nihilist, I'm a little lost. Some of my core opinions to clear things up; Life is meaningless and more painful then pleasurable, humanity is going to go extinct eventually and there's no afterlife or God. I've tried other ideas and even convince myself not to believe these but I gravitate back eventually. Given this, what reasonable argument is there against suicide? Any action feels like a net loss and the only thing even slightly convincing that I've come across to live is hedonism, which still feels very pointless. I'd like direction in my life and some meaning from a philosophical standpoint because suicide isn't pleasant obviously. Any tips? | So, you might think there are some logical problems in your view, but it might help to clarify your view. Why do you think life is meaningless? Do you think anything in life is meaningful or good?
| 17 | 26 |
ELI5: who and how do they determine how many calories are in a particular item of food? | A calorie in your food is the amount of energy that is needed to raise the temperature of one kilogram of water by 1 degree Celsius.
This is done by burning the food in something called a bomb calorimeter. That is a box within a box. A sample of food is put on a dish in the inner chamber of the calorimeter, fill it with oxygen and seal it. In the outer chamber a measured amount of water is filled. An electric spark in the inner chamber ignites the food. As it burns it raises the water temperature in the outer chamber. The amount the water heats tells us how many calories are in the food. If the the temperature of the water goes up one degree it has one calorie. | 20 | 29 |
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CMV: Children should not be forced to complete "family" projects about themselves in school. It's disrespectful to children without traditional families | I believe projects like these are incredibly unfair and awkward for children who do not come from traditional households.
It can be very uncomfortable for a child to have to explain how they don't have a father or a mother, or have to explain their aunt functions as their mother because mommy is in jail...or even worse having to explain that their parents died and they move around between family members or foster homes.
I believe that this not only helps re-hash past trauma they would rather not discuss, but also opens the child to be a victim of bullying.
On top of that, it can create a very awkward situation for the teachers. I even had a teacher friend who admitted to be that she felt uncomfortable doing this once the children started presenting.
I'd really like to see some reasons as to why these family projects are beneficial to children with non-traditional families or broken homes. | Inversely, this can been seen a teaching moment for those kids with 'traditional' families. A teacher could use the diversity of families to show that everyone goes home to a different life. Teaching them to think a little bit more about other people's situations. Learning empathy and compassion for those who may not have what you do. | 1,306 | 1,711 |
ELI5: Will screens continue to have more and more pixels indefinitely, or will we soon reach a point where humans won't notice the difference between, say, 1000 pixels per inch and 2000 pixels per inch? | I recently was looking at the specs of different generations of iPads and noticed that between the 2nd gen and 3rd gen (IIRC) the number of pixels per inch doubled, purportedly resulting in a significantly more aesthetically pleasing experience for the user.
Will screen resolutions continue to get better and better, or will resolutions eventually plateau? If screen resolutions will plateau, at what point? Are we likely to see it in the next decade? In the next century? | All of these answers are correct, but I'd like to add that viewing distance also plays a big role in one's ability to distinguish individual pixels. Just like a building looks smaller when it's further away, so do pixels. Therefore, when using a smartphone, which you hold inches away from your face, you'll want a higher density (smaller pixels, more packed together) than on a TV, which you view typically from many feet away (larger pixels). That's why your phone and your TV can have the same resolution, but wildly different screens. | 240 | 669 |
What actually IS a flame? | Why does fire create a visible flame, why does it exist and what is it made of? | A flame from something like a candle is visible because it's filled with three types of atoms that are going through changes. The paraffin in the candle - wax - is a long chain of hydrogen and carbon that's linked together. Add heat, and that long chain first melts (to form liquid wax) then evaporates (to form that puff of "steam" on the end of a just-blown-out candle wick), and then the links start shattering and it breaks down into carbon and hydrogen atoms, or small groups of the same three ingredient atoms. (Wood does the same thing, actually, except when it breaks down there's more leftover carbon and other stuff, and because it doesn't melt, the process isn't usually as clean).
For a brief moment, those carbon atoms - soot, really, that got broken out of the wax rise due to the heat - gets super-hot and give off yellowish light as a result. This is called "black body radiation". Many of these carbon atoms react with oxygen to form CO2 (carbon dioxide) and give off heat, but before that happens they'll glow. (The hydrogen in there also gives off a little visible light when it burns, but not very much compared to the glowing unburned carbon atoms.
If you slowly burn something like propane on a low-set stove, you'll get a different result. Get enough heat and oxygen in there and smaller molecules start "burning" (reacting with oxygen) before they give off much glow, and instead only produce a light blue light That's why a propane stove's flame set to "low" is blue. But push too much fuel through and you'll get lots of broken-out carbon atoms (which add a yellow color when the carbon heats up, and leave soot behind) instead of a nice clean burn. So cook lots of stuff on "high" on a small stove and you get yellow flame and pots with black bottoms. And burning charcoal - burning carbon - is red, but not BRIGHT red - because it's not burning fast and heating up carbon atoms that have been released by its heat and are floating above it.
So a flame is an area above a fueled heat source such as a campfire or candle or matchstick, that gets hot enough to make fuel to turn to gases or broken-down molecules. Those molecules give off a little visible light as they burn, but depending on the type of flame, the "dust" that's in there gives off a lot of visible light due to the heat, and the chemical reaction gives off a little. | 26 | 22 |
CMV: The "Free Birth Control for Women" issue was and is nonsense. | A woman's employer should be required to pay for her health insurance to cover free birth control. The protest signs read "Birth Control: Not My boss' business" and "every woman should be entitled to free birth control no matter where she works". And of course "my boss shouldn't decided whether I get birth control".
First, your boss does not decide whether you get birth control. Your boss simply decides if the health insurance offered will pay for it. And of course it's not your boss' business what type of birth control you use.
Second, this does not help all women. **If Obama were interested in helping all women, he'd advocate for the Dept. of health and human services give out birth control to *anyone for free* **. This law does nothing for unemployed women who do not have bosses. Instead, he says your employer -if you have one- should pay your insurance provider to do it. Good luck, unemployed and uninsured women. Obama's marketplace might be the best thing since sliced bread, but it does not cover 100% of Americans.
[If fact, women in poverty have the highest rates of unwanted pregnancy.](http://thinkprogress.org/health/2013/09/09/2593011/unintended-pregnancies-poor-women/) They are the most likely to be unemployed/uninsured even after the ACA. The women most effected by the real problem are left out of the "solution."
Also, if this is about helping women not get pregnant, why aren't men included in this? Why don't we get free birth control in this deal? Last time, I checked a man is necessary for an accidental pregnancy unless you're the fucking Virgin Mary. Providing men with free birth control is also very helpful if you're truly interested in helping women prevent unwanted pregnancy which Obama hence is not. Again tying it to a man's employer/insurance is wrong because the ones most likely to be effected by this problem are also most likely to have neither an employer or an insurer.
That's whole issue is non sensical on the face of it. It was an election year and Obama needed an issue that he knew Republicans would fight, but one that makes them look like the bad guy. "Taking birth control away from women" makes it easy for Obama to paint you as a villain.
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> *Hello, users of CMV! This is a footnote from your moderators. We'd just like to remind you of a couple of things. Firstly, please remember to* ***[read through our rules](http://www.reddit.com/r/changemyview/wiki/rules)***. *If you see a comment that has broken one, it is more effective to report it than downvote it. Speaking of which,* ***[downvotes don't change views](http://www.reddit.com/r/changemyview/wiki/guidelines#wiki_upvoting.2Fdownvoting)****! If you are thinking about submitting a CMV yourself, please have a look through our* ***[popular topics wiki](http://www.reddit.com/r/changemyview/wiki/populartopics)*** *first. Any questions or concerns? Feel free to* ***[message us](http://www.reddit.com/message/compose?to=/r/changemyview)***. *Happy CMVing!* | Birth control is essentially a medicine and is used for things other than just preventing pregnancy. It is prescribed by a doctor.
Condoms are not a medicine, are not prescribed by doctors, and can often be obtained for free from places like Planned Parenthood.
Your second point holds no water at all. Just because Obama isn't advocating free birth control for every single person, that means this doesn't help at all? Helping 75% (just an arbitrary number) of women is better than helping none, right? | 57 | 39 |
CMV: There is no logical reason for God to exist | I understand that many people turn to faith in God as a source of comfort, even though that faith is not backed by evidence (like they think there is no evidence of God but the idea of a supreme being looking out for them is comforting and so they are faithful). There doesn't seem to be any proof or explanation for the existence of God, beyond the God is used to explain ideas we don't currently understand with science. It doesn't seem to me that a supreme being really exists beyond our imaginations because it seems like a placeholder for what we don't understand. I am totally open to the possibility, though. What I am asking is if there is any type of proof or reason to believe a supreme being or creator exists beyond blind faith. Any scientific/metaphysical/logical/whatever theories that might explain the need for a Creator? | There’s a compelling scientific theory why humans believe god exists. It’s because evolution has hard-wired us to detect agency everywhere. Our ancestors who saw the rustling bush and concluded there was some agent (that wanted to eat them) rustling the bush survived longer than our ancestors who brushed it off as just the wind. So when we see a thunderstorm, human instinct is to assume that some being must be causing it, and next thing you know, we’ve created Thor. | 36 | 43 |
What is a VPN? Should I use one? Which one? | Think of data traffic like road traffic, with your data being freight on the back of pickup trucks. Think of your home network as an island, with a bridge connecting it to the mainland (built and maintained by your Internet provider). If you want to send stuff to someone, or get stuff sent to you, the stuff gets loaded onto the back of a pickup truck and driven from and to your island.
Now let's say your Internet provider is a bit nosy and installs cameras on the bridge, recording everything that's on your pickup trucks. Of course you don't really transport anything embarrassing or illegal, but you still don't really like the general feeling.
So, what do you do? The solution for most types of VPN is as easy as it is straightforward. On the way out, before your pickup trucks go over the bridge, they stop at a loading yard, where they are driven into large 18 wheelers (just like in "Knight Rider"). These drive over the bridge, to some other loading yard. This can be anywhere, from somewhere close by to being on the other side of the world. Here, the pickup trucks drive out of the 18 wheelers and get sent on their way.
Now all your Internet provider sees are 18 wheelers going between your loading yard and some loading yard somewhere in the world, with no idea what's loaded onto the pickup trucks inside. They also don't know where the pickup trucks are coming from and where they are driving. Also, neither does the final destination of the pickup trucks, they only see them driving from and to your second loading yard outside your island.
All you need to set this up is rent or buy a loading yard (a VPN tunnel endpoint) somewhere in the world -- and (if you only rent one) trust that the guy operating it is not stealing, recording, or tampering with what's on your pickup trucks. | 56 | 56 |
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ELI5: Why a person can’t survive upside down (head down - legs up) for a long time? | Our hearts have evolved to pump blood with a specific amount of pressure, utilizing gravity to assist us. We've always had gravity to help, and many of our bodily functions are dependent on it.
Our hearts are not powerful enough to continually pump our blood through our veins when the force of gravity is acting against us.
This isn't a big deal in microgravity (like the ISS or space in general), because the force of gravity isn't acting against us in any way, so we're able to pump blood relatively normally. | 27 | 35 |
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ELI5: how do you calculate how much an object gets smaller, the further is is away? | Is there a certain ratio for this? Like how long is a 1 meter ruler, 1 meter behind a 1 meter ruler ? | it has to do with a thing called "arc distance"
you don't see heights and lengths, you see how much of your cone of vision an object takes up. a 1 meter long object 1 meter away from you will take up ~53 degrees of your vision. another meter stick 1 meter beyond that would take up ~28 degrees of your vision.
the math is the geometry of an isosceles triangle, where the non-equal leg is the object being viewed. | 147 | 186 |
China has used "fireworks" to break up cloud formations and bring blue skies. Could this technique be used to dissipate a tornado, to save lives and reduce damage? | Clouds exist figuratively and literally at the boundary between being vapor and liquid water. Small variations in wind, pressure, and temperature can cause large scale changes quickly (often by causing a cascade of rain that clears the suspended droplets). Tornadoes are relatively local and energetic phenomenon where an enormous amount of angular momentum has been concentrated in one location. Disrupting an active tornado would probably take a lot more energy applied in more interesting ways than just a transient fireworks explosion nearby. Preventing a tornado would similarly require a lot of energy to redirect the large scale movement of the air volume and prevent it from collapsing. Either way it seems unlikely. | 1,016 | 1,567 |
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[X-men] How many mutant abilities the future sentinels can mimic? | For example, we can see that they minic fire, ice, metal, hardened rock skin, but what if they could touch Quicksilver or Wolverine or the teleporter guy? Would they just simply become machines that are superfast or supernanoregenerating or can teleport everywhere or even read minds and stop motion? With this tech, why not create better worlds? (Instant travel and self reparing machines ect ect) | It appears that the sentinels read the mutant's genetic sequence in order to determine how their powers function, and then adapt that ability into themselves.
Based on that, they should be able to mimic almost any mutant ability, with a few limitations. If their composition isn't organic, for example, they wouldn't benefit from mimicking Wolverine's power, and attempting to mimic Magneto's power might fry their circuitry.
They would also be incapable of cloning powers that came from some source other than the mutation itself. Juggernaut's power comes from magic, and Rogue's flying-brick powers are a result of absorbing someone else's abilities, not from her specific mutation. | 13 | 19 |
CMV: Terrorists are not afraid to die. So fighting terrorists with violence is futile and only makes things worse. | "They want to destroy our lifestyles, our traditions, our loved ones. They live a life that is not right, doing unspeakable things that no person in their right mind would do. They attack us and kill our civilians, without regard for the consequences. We must stop them at all costs. Our lives depend on it"
This speech can interchangeably be pronounced by Obama, Hollande, Bin Laden or Abu Bakr al-Baghdadi, the ISIS leader.
Do you think we in the west would stop and surrender if the attacks continued? Never. What makes you think they would?
Everytime we hit them, they get more people recruited. And civilians are killed. Unless you found a way to succesfully kill **all** of them, vengeance, pride and the cause they fight for will always survive and reproduce. Since we do not have the means to eliminate them completely, no matter how hard we try, fighting this violence with more violence will not stop the vicious cycle.
We should just leave them alone and get as many people out of there as we can.
Basically, we're fucked until the robots arrive.
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> *Hello, users of CMV! This is a footnote from your moderators. We'd just like to remind you of a couple of things. Firstly, please remember to* ***[read through our rules](http://www.reddit.com/r/changemyview/wiki/rules)***. *If you see a comment that has broken one, it is more effective to report it than downvote it. Speaking of which,* ***[downvotes don't change views](http://www.reddit.com/r/changemyview/wiki/guidelines#wiki_upvoting.2Fdownvoting)****! If you are thinking about submitting a CMV yourself, please have a look through our* ***[popular topics wiki](http://www.reddit.com/r/changemyview/wiki/populartopics)*** *first. Any questions or concerns? Feel free to* ***[message us](http://www.reddit.com/message/compose?to=/r/changemyview)***. *Happy CMVing!* | Terrorist organizations require many types of people. They certainly require angry and easily-manipulated foot soldiers who can be convinced to kill/die for their cause. Yes, bombings can help recruit more of those. But successful organizations also require rational planners, people who can be paid to drive trucks, people who can carry messages, charismatic recruiters, middle managers to handle the bureaucracy and records, cooperative merchants, etc etc. A small number are motivated purely by hatred; the majority are either paid for their work or are more afraid of being beaten/killed by the terrorists than they are of being captured/killed by the US.
Increase the level of violence, and you get more angry men willing to die/kill. Yep. But you also get fewer of the rest. The real trick is to ensure that the many people who can be intimidated by terrorists are more intimidated by you. That's a trick that democracies haven't been able to pull since around WWII, but it's certainly available to countries willing to be brutal. Even failing that, democracies can certainly weaken terrorist groups even if they don't end terrorism forever. | 21 | 57 |
CMV: There is overwhelming evidence that IQ is the best predictor of an individual's success in the developed world | Note: this thread is not about race / gender / whatever and I would appreciate it if it did not devolve into that.
Note 2: obviously this isn't true in 100% of cases - that doesn't change the fact that it's statistically the best predictor
Note 3: funnily enough, IQ isn't a good predictor of happiness, which you could argue is the most important variable - but regardless I'm using "success" to generally mean other measurable variables like income and job performance, without getting into a philosophical debate about the importance of these things.
(Some of these hyperlinks are to wikipedia articles because I think wikipedia can be a decent way to introduce someone who isn't trying to do rigorous research to a topic)
1. IQ is the most accurate measurement of [general cognitive ability](https://en.wikipedia.org/wiki/G_factor_(psychometrics). In particular, claims that there are "multiple types of intelligence" are misleading because while you can be smarter in some things than others, on average people's scores in different measurements are positively correlated and you can statistically extract a common factor, an observation that no study has been able to refute.
2. IQ / g is the [best predictor of success](https://www1.udel.edu/educ/gottfredson/reprints/1997whygmatters.pdf) in life, at least within the range restrictions of people born in a developed nation like the United States. If other factors are more important, they have yet to be accurately measured or quantified.
3. [Twin adoption studies](https://www.ncbi.nlm.nih.gov/pubmed/1036363) further establish that IQ is both predictive independent of familial background and significantly genetic (within the range restrictions of non-abusive households in wealthy nations).
4. Many isolated counter-studies fail to adjust for range restriction.
(This is why the military has been IQ testing for over a hundred years and using it to sort people into different professions.)
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> *This is a footnote from the CMV moderators. We'd like to remind you of a couple of things. Firstly, please* ***[read through our rules](http://www.reddit.com/r/changemyview/wiki/rules)***. *If you see a comment that has broken one, it is more effective to report it than downvote it. Speaking of which,* ***[downvotes don't change views](http://www.reddit.com/r/changemyview/wiki/guidelines#wiki_upvoting.2Fdownvoting)****! Any questions or concerns? Feel free to* ***[message us](http://www.reddit.com/message/compose?to=/r/changemyview)***. *Happy CMVing!* | Hi,
Let us tackle some base assumptions that are underlying the viability of the original premise:
#Assumptions
1. Human intelligence can be generally ranked with a one dimension value (i.e. a number)
2. The methods and tools for assessing such a metric is reliable, consistent and objective.
3. Such a metric directly correlates with success.
All these 3 are crucial for the soundness of the IQ as a system. It's good to keep them in mind moving forward, since each one is difficult to implement and/or prove.
#Definitions
To make it clear what we are arguing for, we need to clarify the definitions at work here.
1. **Intelligence** - The ability of an agent to solve problems (or more generally: to increase its freedom as a function of time)
2. **Success** - (a terminal goal state) referring to a configuration where an agent has achieved its desired goals
3. **Metric** - objective quantitative measure used to select and distinguish certain people, phenomena, attributes, institutions, etc.
4. **Developed World** - A blanket term for the ranking of nations (meaning: nations high in the rank based on economic development)
Let me know if you had different definition flavors in your mind when you wrote the original post, so that we can address them and achieve clarity moving forward.
#The Goal of IQ tests
Let us mention briefly the main goals of IQ tests, historically. They were used as a method for splitting human populations based on some metrics of general and shallow cognitive exercises, and check for the deviations from the average person.
For IQ tests, intelligence was defined as follows:
> Intelligence is defined as general cognitive problem-solving skills
IQ tests define this average as the number "100". Anything higher is above average, anything lower is below.
#The nature of IQ exercises
>When a measure becomes the goal, it stops becoming a good measure.
Let us mention briefly that IQ tests have these attributes to them:
- They are intrinsically "puzzle-y"
- They only cover a narrow range of "uses of intelligence" so to speak
- A metric will always reduce a certain measurable factor from what it is in actuality
#Other criterias that have been observed to be very important in attaining success:
- wealth
- health
- soft skills
- work network connection
- social intelligence
- emotional intelligence
- financial education
- discipline and willpower
- grit and perseverance
- time management
- leadership skills
- communication skills
#Other example metrics better than IQ:
Here are some metrics that are better at predicting success than IQ
- Location of birth
- Past work experiences
- Current monetary earnings
- Starting family income earnings
#Questions on the case:
To continue this discussion:
1. As we have seen, if success depends on many more factors other than "general cognitive-ability", why is IQ test the best predictor?
2. Will a high IQ person, that starts in a poor family and is generally unhealthy, have higher chance at success than a person that has low IQ, but with a rich family and a healthy body?
3. Since intelligence and cognitive processes in general are very intricate in their mechanisms, is it viable to reduce the entire process to one number without reducing the original concept too much?
Let me know of your thoughts on this direction, and if you have any questions feel free to start a discussion. | 13 | 15 |
What are good reasons for one to not procreate? | 1) Procreation always entails a possibility of suffering of the child. It doesn't matter how small the probability of suffering is, the mere possibility suffices. To procreate is to gamble with someone's life.
2) To say that pleasures and joys of life are worth some amount of suffering is fallacious for two reasons:
a) What certainty do you have that the child will enjoy life more than he/she suffers?
b) Pain and pleasure are not symmetrical. Any amount of pleasure does not compensate or 'Erase' pain. Would you be willing to experience 1 minute of best pleasure you can think of followed by 1 minute of worst pain imaginable?
3) What certainty do you have that the child would not inflict pain on other sentient beings?
4) Procreating is allocating the existing resources to a newly created life rather than using those resources for betterment of children who already exist and don't have a home i.e. orphans. | 115 | 79 |
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ELI5:How is it that although we don't know all of the words in the dictionary by heart, we can easily spot when something is not a word? | 1. Recognition is easier than recall, so if you see a real world you usually recognize it, even if it's not one you use.
2. In a specific language, certain letter combinations are rare or completely unused. Here are some realistic non-words: famp, droom, pank. Here are some plainly unrealistic ones: qqaq, eoao, thethith, yfg. | 46 | 30 |
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ELI5: What causes grade inflation at universities such as Harvard to get so bad? | The opinion in society that every student should be capable of getting an A in a subject. In the actual design of the system an average student should be getting a C (or 2.0) in a class, above average getting a B (3.0), students gifted in the subject should be the only ones getting an A (4.0). But society has seen fit to assume all students should get an A in a subject if they do the work and that means that the standards to get an A have to be lowered. | 23 | 29 |
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CMV: italian terms aren't sexually discriminating anyone | I'll explain for not italians. In Italy our nouns, adjectives ecc have a sex: if I'm a male I'll be "Studente", but if I'm female I'll be "Studentessa" (Student).
So if I'm expressing to someone specific I'll use the noun that express his/her gender (note: gender and not sex).
When we're talking in plural, so if I'm talking to a group of people of mixed genders, we use the male form of nouns ("Studenti") to express the neutral.
If I'm talking to a group of girls (only girls, no boys) I'll use the female form ("Studentesse").
Nowadays, many people expressed the feeling that this kind of language is not inclusive, because for expressing to a group of people the neutral shouldn't be male. These people believe that we should use a different form with "*" or with the schwa "Ə" ("Student*" or "StudentƏ").
This form has no oral meaning, only written (the oral would be "Studentu", which is nonsense in italian language).
I believe that if I'm talking to a group of people, and I use italian neutral ("Studenti"), I'm referring to everyone, no one excluded. If you feel excluded it's not my problem cause I use the neutral, in my opinion. How can a letter be a reason to feel discriminated, when I'm obviously expressing and talking to everyone.
Am I wrong? CMV | The usual argument against this is that the vast majority of these cases tend to use the masculine form to be 'neutral', which once again tends to treat masculinity or maleness as the default and treats women, femaleness, or femininity to be something that has to be treating as different. There's also the issue with some non-binary people who are annoyed that they cannot escape getting gendered while speaking their language, because there is no 'neutral' option that isn't also used for a gender.
Yeah, it's a change, but languages change all the time. | 295 | 391 |
I believe in eugenics. CMV | Let me preface this by saying, I really do want to proven wrong here. Every time I've confided my views in friends I've been thoroughly chastised, so I would absolutely love to just be able to conform to their opinions, but none of them have ever actually addressed my points other than "OMG that's so racist you're so intolerant I can't believe we're friends" et cetera, et cetera, et tedious cetera. I was raised a southern racist and I am not nearly as bad as my parents as far as that goes. (My great grandparents had ties in the KKK.) I've never been violent, verbally or physically, toward someone just because they were black, and I've never been in a position to hire or fire someone because they were black or anything like that. In fact, I can pretty confidently say that I've never gone out of my way to belittle or worsen the life of a black person (I try not to do that to *anyone*). People don't even know I'm racist, and except for the fact that I have conspicuously few (read: zero) black friends, I behave just like any politically correct, white American, and I don't think there's anything wrong with that in and of itself (but that's a CMV for another time). That being said...
I can't help but feel like eugenics is grounded in truth. The way I see it, humans started out in Africa, where having black skin and being all but immune to skin cancer in very advantageous. Of course black people thrived there, it just makes sense. But for white people to even exist at all, it must have been an advantageous trait at some point. I mean, that's how natural selection works, right? Someone somewhere some time was born with lighter skin, and that was somehow advantageous, and eventually his descendants were what we would recognize as white. If white people evolved in Europe, that means that in the European climate, being white is an advantage. Now, the question is *how* it's an advantage. I see four possibilities:
1. It somehow proved to be a survival trait
2. The resources saved by not producing melanin in the skin somehow helped development (not gonna lie, this sounds like complete bunk, and I wrote it)
3. It was not necessarily a survival trait, but it made reproduction easier (or just made it occur more often). To put it bluntly, if lighter skin was more attractive, it would prosper as a trait.
4. The white skin is a complete coincidence, and there were other things that made white people prosper.
I can't think of any reason why #1 would be true and #2 is probably untrue anyway, but I've seen #3 to be true. You see far more black men go after white woman than white men go after black women. In India, having lighter skin is considered attractive too. There's a certain sweet spot between pale and dark that seems to be considered universally attractive; it's the reason Rihanna's PR people lightened her skin on her posters, it's the reason Indian aristocrats sought to stay indoors to be more pale, it's the reason white women sunbathe. There's some skin tone that everyone likes, and it's much closer to white than it is to black.
Now, even if that whole last paragraph is wrong. Even if it was the fourth possibility I presented, that would still mean that white people have something in them that is superior and allowed them to first spread all over Europe, then enslave most of Africa, then kill most of America before settling there, and basically conquer the whole world with the exception of Asia (so, like, half the world). I've heard people say that the only reason this happened was because White people were so violent and aggressive, but isn't that itself a favorable trait as far as natural selection goes? If you kill your competing genes, your genes survive.
Now obviously the Eugenics cited by the Nazis and by Tom Buchanan is all rubbish pseudo-science, but couldn't it be somewhat grounded in truth? Couldn't the reason that black people were impoverished in America (and are still disproportionally represented in the lower income brackets) and never "made it big" like white people did that they are, to put it plainly, inferior?
CMV. | From a natural selection standpoint it just means that people are adapted to different environments. It does not imply superiority. It just means that some people perform better in certain areas while others have areas where they are superior. This is the premise of diversity being an improvement | 28 | 18 |
When a celestial object pulls on a beam of light, does the light pull back? | Since photons are clearly affected by gravity, and since to every action there is always an equal and opposite reaction, would it be prudent to assume that light induces gravitation?
:D | In General relativity, which is the best theory of gravitation that we have, curvature of space is caused by energy and momentum. Light/photons have energy and momentum so therefore cause a curvature of space. The amount of curvature/gravitation caused by photons though is so small that it would not be possible to measure it, and in calculations is safely ignored.
So the simple answer to your question is: yes. | 20 | 41 |
Eli5: Why are 'competitive/Paralympics' wheelchair's wheels slanted? | So I was watching [this](https://www.reddit.com/r/nextfuckinglevel/comments/j00qlh/para_badminton/?utm_medium=android_app&utm_source=share) video of two (apmutees) people playing badminton on wheelchairs and noticed that the wheel were slanted and I can't understand why they do that...so smart people of reddit please tell me | The slanted wheels help stability and stop the wheelchair tipping over during am impact (in the case of wheel chair rugby) or allow you to turn quicker (in the case of racquet sports, without risk of tipping over). | 32 | 25 |
CMV: The same logic that argues for the acceptance of transgender people can be applied to 'trans-race' people | Please let me preface by saying that I do believe trans men are men and trans women are women. If you want to challenge that part of my view, fine, but I'd rather have a focus on the 'transrace' concept. I'm a POC, and while I would be somewhat more skeptical of 'transrace' people than transgender people (which is in part due to stigma and in part due to the lack of research that has actually been done into being 'transrace'), I don't understand why so many people who believe being transgender is valid are so quick to dismiss people who say they are trans-race.
* Trans people experience gender dysphoria, the 'cure' for which is to transition. Hypothetically, if a person felt physically and mentally uncomfortable with their own appearance to the degree of dysphoria in terms of race or ethnicity, would the 'cure' not be to transition to a different race?
* Many people say that trans people don't necessarily need dysphoria, just the desire for society to perceive them as a gender that isn't the one they were assigned at birth. In this case, if someone wanted society to perceive them as another race/ethnicity, is there any significant difference?
* It's true that being a part of a certain race or ethnicity isn't a 'feeling' but rather more of a cultural experience, or even just a different appearance from other ethnicities or races. However, many people could argue the same about gender--there isn't any way to 'feel' like a certain gender outside of the cultural experience and societal perception.
* Having people be trans-race isn't technically harming anyone. Acknowledging trans women are women does not harm cis women, and I feel that being transrace could even be considered less controversial, just because there would be no arguments about sports or bathrooms or other transgender 'hot topics.'
I do realize that there are a lot less people claiming to be trans race, and there is a lot less history backing it up, but I don't think it can entirely be dismissed because of the strong pushback against it--I'm sure that fifty years ago, many transgender people were closeted too. I also realize there's almost no hard science behind it, but it's so quickly dismissed that I don't believe it's even been studied seriously.
Please CMV. | >Hypothetically, if a person felt physically and mentally uncomfortable with their own appearance to the degree of dysphoria in terms of race or ethnicity, would the 'cure' not be to transition to a different race?
The problem with this is that it's all hypothesis. There is no studied phenomenon of racial dysphoria and we certainly haven't developed a cure for this hypothetical condition.
Transgender people are very real, their experiences are very real, we know that. There isn't a community of transracial people, and even if there were, it doesn't mean their experiences and condition would be similar to trans person's, even if it makes sense from a hypothetical standpoint.
Consider Ja Du, a white woman who claimed to be Filipino? Her reasoning? She really likes the culture and watches hours of History Channel on the subject. Is that an identity issue or someone engrossed in a subject?
>Having people be trans-race isn't technically harming anyone
I mean, it's cultural appropriation at best, outright fraud and mockery at worst. Rachel Doleazal lied about her identity and led a chapter of the NAACP under false pretenses. That is like a whole new level of blackface. POC don't need a bunch of white people running around acting like ambassadors for their culture and representatives of their struggles. | 27 | 18 |
ELI5: How can toddlers remember how to walk,"talk", know certain words but when we get older we can only start remembering things as young as 4? | The type of memory that babies to do quite well is referred to as "semantic memory". This allows them to know their parents, recognize the foods they like and don't like, remember to not do something that they learned sucked when they did it the first 10 times and so on.
What they lack is referred to as "episodic memory". The best theories we have currently tell us that we lack the ability to pull together distinct memories into a coherent rememberable "episode". E.G. the experience we have in the visual context isn't bundled with the auditory, the emotions, and then also isn't anchored around other memories and episodes. Basically, we have a shit ton of input, but no scaffolding on which to place it.
Most believe that the pulling together of this requires the development of the hippocampus beyond where it in an infant - it supplies the contextual glue and scaffolding to form what an adult thinks of as "memory". That said, the hippocampus may not be developed, but also may not have enough stuff in it yet on which to have found patterns and meaning. Until you are 2-4 it isn't physically developed enough, and it hasn't had enough raw material run through it to develop patterns and coherency.
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ELI5: Why humans fat mostly stores, or at least shows, at the stomach and doesn't so the same effect on the back. | There is an evolutionary advantage to having the majority of your mass close to (Edit: close to, or slightly below) your center of gravity. Having fat evenly distributed around the body would mean that movement of arms and legs would require more energy. Keep in the limbs relatively lighter than the torso makes it more energy-efficient to move (think of how alloy wheels are used in performance cars - that's because lighter wheels need less energy to rotate them fast).
Humans evolved to be able to walk long distances. We can outlast almost every single land animal in terms of endurance because walking on two legs takes less energy. Keeping those two legs light is a huge advantage too. Having all the fat stored around the middle (tummy and butt) makes it easier to maintain balance. If we had big arms and thin legs, we would be top-heavy and easy to topple over.
Basically it is all about saving as much energy as possible, and being as agile and stable as we can be.
As to why it doesn't collect or show on the back ; presumably because we evolved from creatures walking on all fours (see dogs, cats, cows, etc - all have their spines as a support structure, while the fat hangs below).
So before we walked on two legs, several species previously, we too used to have the same structure where our spine acted as a support beam and all our organs and fat would be suspended below it. That also kept the center of gravity as low as possible, making those animals much more stable. When we finally stood up on two legs, there was no evolutionary disadvantage to continuing storing the fat in front and so it persisted. | 19 | 23 |
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[The Culture] What's with all the humans? | So I'm listening to *Consider Phlebas* and it seems almost everyone except the Iridans and their companion race are some subspecies of human, but the book is listed as taking place during the earth date of 1381. Where'd all the people come from? | Humans is a broad, more understandable term for warm-blooded intelligent beings with primate ancestry. The 'humans' you speak of evolved similarly to those primates detected on this 'Earth' planet, but Culture Normal Humans are closer to Peak Human than they are to Earth Human. As you make your way through more of the Culture's history, you'll discover more Humanoid/Human species. The Culture itself was formed by several groups of Human species, each evolving separately on their own worlds.
Evolution, it turns out, is far from unique. | 41 | 30 |
ELI5: What is click chemistry? And why is it special/useful | Essentially it's a class of chemical reactions which meet certain criteria. If they meet all the criteria, it's a bit like snapping together lego bricks. The molecules just 'click'.
You want the reaction to:
* have one product rather than a mixture
* to not need a special solvent so it can take place in water
* work in the presence of oxygen
These reactions mean you can even do the reactions inside living cells, which is otherwise not somewhere you can do chemical reactions!
Standard chemical reactions often produce a mix of products that need to then be separated, and only work in strange solvents and under nitrogen atmosphere. | 16 | 26 |
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[General] If someone is turned into a vampire but freely chooses to never consume human blood, not even once - does that individual gain or lose any advantages or disadvantages to doing this? | This depends on what universe you're in.
In *Buffy the Vampire Slayer,* Angel subsists indefinitely on animal blood, and merely doesn't like the taste.
In *Vampire: the Masquerade,* animal blood is much less potent than human blood, and "vegetarian" vampires must consume more of it.
In *Vampire: the Requiem,* not only is the above still true, but only weak vampires can exist at all without human blood - and particularly powerful vampires consume vampire blood. | 73 | 42 |
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Why does looking through a tiny hole make things focus? | When I forget my reading glasses and need to read small print I can curl up my forefinger (like making a fist, but only my forefinger) tight enough to leave only a tiny pinhole in the center of my curled finger. If I look through that tiny hole by putting the finger very close to my eye this makes the print come into focus.
Why? How does this work? | Focusing just means taking light rays that have slightly different directions and making them all meet at the same point.
When you look through a tiny hole, only the light rays that were already going to meet at the same point get through. The light is already focused. | 3,566 | 3,560 |
ELI5: Why do studio photographers use flash bulbs to light their subjects? Wouldn’t continuous lighting be more time-efficient because you could see what you’re lighting as you light it? | There’s more to it than time effectiveness. Studio photographers often use what’s called strobe lights. Strobe lights can have two types of bulbs in them that offer different functions:
1. One light is a constant light, called a modeling light. It’s purpose is just to provide light so you can see what you’re lighting as you light it.
2. The other light is the flash tube. This basically puts out a much brighter source of instantaneous light.
The benefit behind using a light that flashes is as long as it’s brighter than the light around it, it freezes motion. This allows you to maximize your camera settings to get the best quality picture with sharp settings.
Some photographers do use constant lights, such as Jason Lanier. He likes using them because he knows they’ll always work, and he can always see what they’re putting out. So they can work well. They can also help restrict the iris and allow the subject to show off their eyes.
However, cost wise, a really good set of constant lights will set you back a pretty penny compared to flashes or strobe lights. Those cheap one’s on amazon are garbage. Your camera settings will often be higher quality with regular flash then constant lights and allow you to freeze motion more easily. Some constant lights will also heat up much more quickly, and you don’t want the subject getting sweaty. Lastly, it’s really not that hard to guess and check lighting, and experienced photographers will have already set the lights up before the subject even gets there. | 21 | 17 |
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ELI5: Why can't you invent an imaginary number for division by zero like you can for a square root of a negative? | Mathematicians like when things work nicely and in almost every case, allowing division by 0 will make things not work nicely.
For example, one of the nice things about numbers is that we can multiply numbers in whatever order we want and still get the same result. For example (2 \* 5) \* 4 = 2 \* (5 \* 4) and 2 \* 3 = 3 \* 2. (Mathematicians call these "associativity" and "commutativity" of multiplication.)
Another nice property is that a(x + y) = ax + ay. For example, 2\*3 + 2\*4 is the same as 2(3 + 4). (Mathematicians call this "distributivity" of multiplication over addition.)
Let's see what happens if we allow division by 0. Let's just make a new thing called X and we will define that 0 \* X = X \* 0 = 1. So 1 / 0 = X.
Then (3 \* 0) \* X = 0 \* X = 1. Except that 3 \* (0 \* X) = 3 \* 1 = 3. But 3 is not equal to 1!
So this breaks one of the rules we like about multiplication. Maybe this is no biggie, maybe we can just let it slide. Let's keep exploring.
Let's check if distributivity still holds. How about X \* (0 + 0)?
X \* (0 + 0) = X \* 0 = 1, but X \* 0 + X \* 0 = 1 + 1 = 2. Another problem... we lost distributivity.
If you keep exploring, you'll likely find even more problems with assuming that X = 1/0 exists.
We now have two options here: First, we can allow division by 0, in which case we would have to abandon a bunch of things that work nicely with arithmetic. Or, second, we could just say that X does not exist. The second option is almost always the best option. | 1,487 | 1,333 |
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Can you fuse any two pieces of the same material in space just like metal? | We know that on earth here when we cut two pieces of metal the freshly cut surface oxidizes preventing the metal from joining back together,
Though in space the metal does not oxidize and is able to fuse back together into a single piece of metal,
My question is, is this the case for all material? For example wood, (I don’t know why we can’t fuse that back together on earth) if we took a piece of wood to the vacuum of space could we fuse it back together just through pressure?
And if we can’t, can someone explain why we can’t? | For this kind of cold-welding process to work, you need a few things to happen:
1. The two surfaces have to come into atomically close contact, with relatively few gaps between the materials, to form a strong bond at the interface to be joined. In other words, the atoms or molecules have to be in close enough contact to form a chemical bond.
2. Once in close contact, a large fraction of the atoms have to be chemically capable of forming bonds with each other.
Metals often satisfy these two conditions because they behave something like atoms floating in a “sea” of electrons, with a lot of flexibility in the spatial arrangement of the atoms. This makes the metals malleable (edit: and more importantly, ductile), so the interfaces can be smushed together to remove most gaps or imperfections at the interface, especially if there is no air in the way. Can’t do that with wood, which has a more rigid structure (made mostly of organic molecules that are much more specific in their spatial bonding geometries) that can’t be deformed much from its equilibrium structure.
Also, since metal atoms can easily form metallic bonds with many neighbors, which are often the same kind of atom, one part of the surface will look much like any other, and you don’t have to “match” the surfaces perfectly with respect to binding partners. Every atom at one surface could pretty much bind any atom of the other surface, with little reorganization needed. Wood, on the other hand, is a complex mixture of organic molecules comprising carbon, oxygen, nitrogen, hydrogen, phosphorus, and other elements that bond with each other in rather specific ways. For any given atom on a surface, it’s unlikely it’ll find itself next to an atom on the other surface that is capable of binding to it without significant input of energy (and probably catalysis of some kind).
So, with wood, there will be significant gaps throughout much of the interface, and most of the parts that do touch won’t be reactive with each other. So, no bond will form. | 39 | 32 |
Since Hegel is infamous for how ambiguous his writings were, how much can we really trust what his translators thought he wrote? Maybe his works come across as completely different in english than in german | Ambiguity and difficulty in Hegel's writing is typically not because of his word choices, but because of the actual thoughts he's trying to communicate. We can take an example passage from the *Phenomenology of Spirit*:
> Das Selbstbewußtsein hiemit seiner selbst nur gewiß, durch das Aufheben diese andern, das sich ihm als selbstständiges Leben darstellt; es ist *Begierde*.
This is translated by Terry Pinkard as the following:
> Self-consciousness is therefore only certain of itself through the sublating of this other, which, to itself, exhibits itself as self-sufficient life. Self-consciousness is *desire*.
With one notable exception (*Aufheben* translated as *sublating*), these words are all rather straightforward, both in German and in English. The difficulty and ambiguity comes not in the individual words, but in their implications; that is, we aren't confused by *how to translate* 'Selbstbewußtsein ist Begierde* [self-consciousness is desire], but by *what this implies*. | 30 | 22 |
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CMV: Donald Trump advocating the murder of terrorist's families means he publicly supports killing innocent people. It is a bad idea to elect a president that said this. | [Here's the quote](http://edition.cnn.com/2015/12/02/politics/donald-trump-terrorists-families/)
By the way, I do not want some philosophical argument in support of nihilism. I do not want some vague bullshit about how murdering innocents isn't wrong because 'there's no such thing as right and wrong'. I want my question to be answered in the spirit in which it was asked. If that's the best you can do, don't bother.
I'm also not convinced by the whole 'He tells so many lies, we don't know if he'll be bad' argument. Well then there'd be no reason to vote for him: anything he says that you support could also be lies. And if there's a chance he might be serious about this, it's a bad idea to elect him.
And I'm sure there are other political atrocities that are just as bad as this threatens to be. But have any other presidents so openly announced that they're okay with killing innocent people (genuinely curious)?
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> *Hello, users of CMV! This is a footnote from your moderators. We'd just like to remind you of a couple of things. Firstly, please remember to* ***[read through our rules](http://www.reddit.com/r/changemyview/wiki/rules)***. *If you see a comment that has broken one, it is more effective to report it than downvote it. Speaking of which,* ***[downvotes don't change views](http://www.reddit.com/r/changemyview/wiki/guidelines#wiki_upvoting.2Fdownvoting)****! If you are thinking about submitting a CMV yourself, please have a look through our* ***[popular topics wiki](http://www.reddit.com/r/changemyview/wiki/populartopics)*** *first. Any questions or concerns? Feel free to* ***[message us](http://www.reddit.com/message/compose?to=/r/changemyview)***. *Happy CMVing!* | Looking at his statement as charitably as possible, he very well may have been referring to families of terrorists who actively harbor them, knowing their terrorist identities. While harboring a criminal isn't a crime worthy of death imo, it would still make them far from innocent if they did so knowingly. | 27 | 257 |
CMV: The biggest problem with the canonical Star Wars universe is the need to constantly reference the original trilogy | When speaking of canon, I'm referring to the current canon as defined [here](https://starwars.fandom.com/wiki/Canon), which states
> As of April 25, 2014, the only previously published materials that are considered canon are the six Star Wars films, the Star Wars: The Clone Wars television series and film, novels (where they align with what is seen on screen), and Part I of the short story Blade Squadron
Since then, the recent sequel trilogy features the lead actors from the original trilogy reprising the same roles. Spin off movies like Solo and Rogue One expand on characters or events mentioned in the original trilogy. Disney+ series like the Mandalorian, Obi-Wan, The Book of Boba Fett, and the recently announced Andor do the same. Even the recent video game, Star Wars Jedi : Fallen Order, has a direct link to the original trilogy with an appearance of one of the original trilogy villains.
As such, the Star Wars universe is stuck rehashing the ideas/concepts of a dated, nearly five decade old story, written by a man who openly admits [that dialogue](https://www.empireonline.com/movies/features/star-wars-archive-george-lucas-1999-interview/) is not his [strong suit](https://www.youtube.com/watch?v=2tLf1JO5bvE). The end result is that rather than favor something entirely novel, additions to the canon fail to expand or evolve the universe but instead becomes something more iterative and overly dependent on nostalgia. | What is the point of any established universe that doesn't reference other previously established parts of that universe?
For example what if they made a Game of Thrones series but it didn't reference any previous characters, or houses, or events? In what sense would that be a Game of Thrones series other than following the general theme? | 18 | 36 |
How do slide rules use logarithms to perform calculations? | I went about making a very basic slide rule with two strips of card stock and how it multiplied decimals wowed me. I know that they can also be used to divide, square/cube (root) and many other functions all based off the log system, but what exactly is it about logs that makes it so? Also, what is an anti-log and what does it mean to take an anti-log? | The key property of logs that you need to know is this:
log(a)+log(b)=log(ab)
So if you take the sliding strip of the rule so that it starts a distance log(a) from the beginning of the first strip, and then look at the spot a distance log(b) from the beginning of the sliding strip, you'll be at a spot a distance log(a)+log(b) from the start of the first strip, i.e., a distance log(ab) from the start of the first strip.
Since the strips are labeled logarithmically, you find the spot at a distance log(a) by looking for the label a, etc., and so your slide rule will do multiplication easily.
(By analogy, if you took two ordinary rulers, labeled linearly, you could make a slide rule that did ordinary addition.) | 17 | 42 |
ELI5:Why does going to bed later than usual but sleeping the same amount of hours as you normally would, feel worse when you wake up? | The major contributing factor is your circadian rhythm. This rhythm is basically your natural biological clock. However it does not run exactly on a 24 hr cycle, there are slight deviations naturally and other factors can contribute to altering your biological clock.
The next factor to take into account is which stage of the sleep cycle you are waking up from. There are typically 5 stages of sleep, stage 1/2 are "active" sleep cycles, your brain activity is still highly active and almost indistinguishable from a wake person. In stage 1/2, you are also more likely to respond to stimuli, such as someone calling your name. Stage 3 is regarded as "inactive" sleep cycle, this is the stage where your brain activity drastically drops, preparing your brain and body to enter stage 4. In stage 3, a person is much harder to wake up and waking from this stage leaves a person exhausted and generally disorientated. Stage 4 sleep is where actual rest and rejuvenation occurs. In this stage, your brain activity is picking up slightly but still in a mild manner, not too much to be called wakefullness, but enough to signal repairs in the body. Lastly is REM stage, this is where your brain is now increasing activity and causing dreams. After REM, the cycle repeats back from stage 1.
Basically as you sleep, you go through this 1-4+rem cycle over and over, with each cycle lasting about 90 mins. Depending on what your body needs, stage1/2 will shorten as you go through the sleep cycles and lengthen stage 4 for rest and recovery or REM sleep. If you wake from REM, you will feel refreshed and ready, that is why most people dont remember dreams or recall a dream suddenly disrupted by waking up. If you wake up during stage 3/4, you will feel tired and exhausted, your brain was trying to turn down the power after all, and signal the body to recover from things like exhaustion or injuries.
So thats it, a bit long for ELI5, but its a complicated question that takes many things into account, as is common when talking about neurological issues
Edit: forgot to talk about sleep deficit and how that also contributes alot, but im on mobile and cant continue forever. | 388 | 1,667 |
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What type of healthcare system is supported by economists? | Vouchers, single payer, public option, etc? Can someone show me some surveys? | This topic falls under "health economics" which is a branch of economics that deals with health care systems etc.
It depends on what your values are. On the most basic level its a question of whether you are utilitarian or egalitarian. Do you wish to maximize health outcomes of population y with resources x (max sum of outcomes) or do you wish to maximize the health outcome of those worst off (max min).
So basically, you have to start with what makes a system better than an another system? | 73 | 107 |
[Marvel] does war machine send his suit to tony for repair and upgrades since he's the only one who knows how this tech works. Does tony give him this service? | When considering the War Machine armor, the systems come in two classes; proprietary "StarkTech" hardware like the power systems, repulsor thrusters, etc, and more conventional military hardware. Most of the ordnance on the War Machine are conventional military weapons modified to be able to interface with the suit, and their care and upkeep can be handled by the armorers and technicians of the USAF. The StarkTech components are tougher, and a limited number of people (like Rhodes himself, technicians on contract from Stark Industries, Tony, or a limited number of outside experts) are trained and qualified to do stuff like swap out a dead thruster or upgrade the internal sensors and controls. If needed, during periods where Tony and Rhodes are on good terms, Tony himself could show up to help resolve a major issue with the suit. | 559 | 922 |
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ELI5: How are college professors who require students to pay for textbooks they work on not barred by anti-trust laws? | In the United States, it's extremely common for a professor to require students to pay for books for a class where the professor has paid for the book, or they receive some form of compensation for books sold.
This seems like a direct violation of anti-trust laws: To have someone requiring the purchase of a product, that they receive compensation for, in order to pass an educational course. Even at a private college.
How the hell does this keep going on? I would also like to know if the same applies to situations where the school and the textbook company are in a business deal. | Anti-trust laws deal with the domination of a sector by a specific industry. If you don't want to pay for the book, you're free to take the course from another professor or another college. Anti-trust laws really have no bearing. | 33 | 39 |
Why did Trump's tax cuts cause corporate stock buybacks rather than additional investment? | Premise taken from a few articles, [this one](https://www.marketwatch.com/story/now-we-know-where-the-tax-cut-is-going-share-buybacks-2018-02-22) being representative. None of them really concern themselves with the why. I would have thought that it'd be in companies' interest to take the savings and use them to make more money.
There are three broad categories of answer I can see.
The first would be that this was caused by something specific to the structure of the tax cuts. I don't really know anything about the technical details.
The second would be that good investment opportunities are scarce and already being adequately filled, so the money has no other place to go.
The third would be if companies are concerned these tax breaks will be reversed shortly, before the gains from any new investments would be realized.
Are there other possible explanations I should be aware of? Are any of these explanations better than the others? | > The second would be that good investment opportunities are scarce > and already being adequately filled, so the money has no other
> place to go.
This is definitely part of it, especially with such low interest rates. Any investments with an expected payoff higher than the cost of borrowing should have been made already. | 21 | 26 |
Eli5: how does cancer spread from one part of the body to other parts? | Cancer spreads through a process called metastasis. In metastasis, cancer cells break off from their original location, travel through the lymph system and your blood, and form new tumours in other parts of the body. | 46 | 52 |
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How do small birds survive sub zero temperatures with such little body mass? | I understand the concept of hollow, thus insulating, feathers, but it just amazes me that these little creatures are still flying about. It's been below zero for several days where I live. Their bodies are so small, they cannot possibly produce much heat. | MS in biology here...not sure about that specific species of bird, but usually keeping warm is going to involve a few things, 1) maintaining body heat through the expenditure of energy, so metabolism needs to be supported by adequate food consumption, and 2) preserving that body heat through insulation such as fat and feathers. They may/will also have behavioral adaptations such as huddling together, or being able to find the warmest places in their immediate environment to find shelter. | 89 | 571 |
I'm scared to move to the US due to issues such as healthcare. CMV. | Background: I'm a 24 year old danish male, finishing my masters degree in electrical engineering.
I've been living in Berkeley for the last half year or so. During this time I've been around California and seen a bunch of this awesome, untamed country. There's so much nice to say about this place - unfortunately also a lot of bad things.
I've seen a lot of things on reddit about the american healthcare system. I understand that this information might be as biased as some of the information americans receive about the "death panels in Europe". But some things keep popping up, such as insurance companies routinely dodging out of their responsibilities and people having to pay to ride in an ambulance.
This is an incredibly scary thought to me, that I could in essence be left for dead or be bankrupted by unfortunate medical events.
I've gotten two job offers while being over here. I'm considering taking one of them, but I feel like it may be better to just stay in tiny little Denmark and not have that risk hanging over my head.
Convince me that i'm being paranoid. Change my view. | If your job comes with health insurance (which every company trying to hire electrical engineers from Cal will offer) then the best care in the world will be available to you. UCSF and Stanford are in the top 5-10 health systems worldwide.
The US offers the most expensive healthcare in the world. If you can afford it's great. If you can't, then you're totally stuck. | 23 | 21 |
ELI5: Do veins work like muscles? Does physical stress(exercise) make them bigger and create more of them? How are new veins formed? And what causes new veins to form? | First, veins are one type of blood vessel, which also includes arteries and capillaries.
Second, in some ways, yes, but also no. Exercise doesn't make them "stronger" because they're not muscles, but it keeps them unclogged, makes it easier for them to expand and contract, and makes them more efficient.
New blood vessels are formed through a process called angiogenesis. Things that that trigger new blood vessel growth include obviously growth, exercise (more muscle mass requires more blood vessels to supply the extra muscle), gaining weight (more fat requires more blood vessels to supply the extra fat) healing wounds, and cancer, since tumors require a lot of blood flow. | 28 | 18 |
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[Fullmetal Alchemist] [spoilers] Could Ed learn alkahestry? | At the end of the manga/Brotherhood, Ed gives up his ability to use alchemy. Does this prevent him from using alkahestry as well, or could he theoretically learn it? | Alkahestry differs from alchemy in that they use different power sources, the former 'the chi flowing trough the earth' ^((whatever that is supposed to mean)^) and the latter the tectonic shift as well as the power of the Homunkulus' philosophers stone.
They still get channeled the same way, through the gate of the respective practitioner, and so Ed probably can not do it. | 28 | 41 |
If polar caps are melting, how do we measure altitude of a place in a precise, consistent and time-invariant manner? | Altitudes are measured with respect not to the instantaneous sea level at any point in time, but to a datum surface which is periodically refined or replaced. At present, the most widely used datum is the WGS 84 reference ellipsoid.
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[MARVEL] Why doesnt Iron man put multiple arc reactors in his suit to avoid low power level issues? | Optimization requires making tough choices. If you want to have the flak and chaff guns, the flares, the tank busters, lasers and repulsors, missile barrages, air current detectors, internal fire suppression system, and a cutting edge AI that's smarter than most humans, you've gotta cut out a few extra "nice-to-haves".
How often does he run out of power anyway? Usually it's only after a prolonged engagement for the fate of the world. Day to day it's fine. | 166 | 180 |
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[Judge Dredd] Why was Mega City 1 spared in the Atomic Wars? | Mega City 1 appears to be built over some pretty massive population centers like New York, Washington DC, New Jersey, etc. How were these places still intact enough to glom together to create Mega City 1, while places like the Mid-West were nuked to a radiation filled hellscape? Wouldn't this area especially be a primary target in a nuclear war? | A combination of technical difficulties with incoming missiles and point defenses could have allowed for enough intact infrastructure to exist. The better question is, how the hell do you feed and power that place when the entire rest of the country is a radioactive waste? | 38 | 65 |
ELI5: When looking straight at a light, why does the shape of it stay in your vision? | When we see light, it enters through the pupil and shines onto the retina, the light-sensitive lining at the back of our eyes. If a bright light shines on the retina long enough, the part of the retina it’s hitting becomes somewhat desensitized to light, so when we look away, the desensitized part doesn’t immediately respond to the new input it’s receiving. This causes us to perceive a negative space in our field of vision that’s in the shape of the bright thing we were just looking at until the affected part of the retina becomes sensitive to light again. | 43 | 49 |
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ELI5: How do antibiotics work? | How does one antibiotic kill different versions of bacterial infection? And if so, why can't it kill ALL bacterial infection? And why can't it work on a virus? | They destroy or weaken various parts of how bacteria work.
For example, penicillin infiltrates the cell wall of bacteria and weakens the structure. This causes the bacteria to die.
Other antibiotics block bacterial replication or other cell functions. The key is to have one that blocks bacteria from growing while being inert to human cells. | 28 | 25 |
ELI5: How do they calculate volumes of lakes and oceans when the depth is inconsistent and the shape is irregular? | For lakes they do extensive charting. You can look up Great Lake charts and see that they have depth readings throughout the entire lake. From there, they can estimate the volume by assuming some gradient between the locations of their readings. The more readings that are taken, the more accurate the estimation will be. It’s probably similar for oceans. | 440 | 466 |
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ELI5: Why is it that baked good containing eggs like cookies don’t have to be refrigerated when eggs themselves or hard boiled eggs do? | Bacteria needs a specific environment to grow the following 6 things contribute to its growth
1. Food
2. Acid
3. Time
4. Temperature
5. Oxygen
6. Moisture
Take away any of these factors (or add to much in the case of acid and temperature) and bacteria cannot grow.
So a fresh egg has food (the egg itself), low ph level, moisture (whether from humidity in the air or the egg itself) , and if sitting out oxygen and temperature also acting against it to help create a perfect environment for bacteria to grow.
Add that egg to a dough and bake it. For a cookie to rise you either use baking soda or baking powder, baking powder has a leavening agent as well as an acid to make it rise, baking soda needs to react with an acid to cause it to rise (usually cocoa powder in cookies but can also be numerous other ingredients) acid will help kill the bacteria although these small amounts aren't enough to make it safe. Baking does something else to that cookie it heats it up. Most bacteria die around 160 degrees feirnheight you bake your cookies at 350 feirnheight this kills any bacteria that may have been present in that egg/dough mixture. The baking process also takes away moisture and dry out the dough significantly. So we have added acid, added temperature and removed moisture. These 3 things inhibate the growth of that bacteria and allow you to keep your baked goods sitting on your counter. | 60 | 61 |
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ELI5: How do glasses correct astigmatism? | I can understand how glasses fix myopia and hypermetropia, but I can't get around the fact that glasses can correct imperfections in the cornea and lens.
From what I could understand, astigmatism happens when there are multiple focus point on your retina, but how can glasses fix this issue without having to be uniquely crafted for each imperfections?
Thank you! | Ideally cornea and eye lens have perfectly round curvature. Astigmatism happens when either cornea or eye lens have elliptical (egg-shaped) curvature instead, producing two overlapping images on the retina. The precise shape of that curvature can be measured with the various instruments that ophthalmologists and optometrists have. Glasses can be made to compensate for the curvature imperfection. | 273 | 392 |
I feel laws should have no moral footing. That the purpose of laws is purely to make society function efficiently. CMV | To elaborate, I believe terms like freedom, liberty, justice, right/wrong, good/evil, etc… don’t inherently work as an argument to enact or abolish any particular law. Sometimes these thoughts line up with making society function, but not always, and alone should not be a reason for enacting a law. You can, however, use them as a basis of why a law can work.
For example: “Freedom of speech is required to have a productive society because without this we cannot have debate on issues that are unpopular. Without this debate and the considering of things that are not popular, we cannot change public opinion, and in turn, change policy to one that would better benefit the populous as a whole”. See, the argument for freedom of speech is not made because freedom is right, it is made based on it’s benefits to society as a whole.
Argument, from the past couple of days here on CMV:
On abortion legality, the question continues to be “where does human life begin?” This question is great when debating the morality of abortion. However, when the legality of abortion is brought up, the question should not be this, but “how does the legality of abortion benefit/hurt society as a whole”. When it comes to legality, this is the proper question.
Another example of a current law on the books that is there, IMO, for the right reasons, and shows that this point does not lead to anarchy: Murder is not, or should not, be illegal because it is morally wrong. It is illegal because allowing murderers to walk free creates vendettas/vigilantism which hurts many innocents in the process and removes otherwise productive members of society to seek justice (I didn’t use justice as the reason, I used it as an action people will seek without the state assisting in obtaining, which will harm society as a whole).
Basically, murder, rape, theft of property, rights of property, etc…all have their basis in making a society run and optimizing as many members of said society. The also have a basis in morality, but I don’t feel that is the reason for their existence. Other laws that I believe are right to be on the books, such as seat belt laws, sin taxes, progressive taxes in general, are all things that are not really dealing with morality, but they do help society function better/efficiently (at least that is the argument).
My point being that if we believe that law=morality, or use morality to justify laws, we wind up with many laws that will actually be detrimental to society, i.e. marriage laws, laws on adultery, premarital sex, lying, decency laws, etc… things a significant portion of the country believe to be morally wrong. You may hear this and think “I don’t believe those things are wrong”, well maybe that is why we shouldn’t base laws on morals, everyone’s are different. Shouldn’t the one and only goal of laws be to make the country run better? That if you leave this premise in any way, then you have left the debate of law. | How do you define running better? If we were to enslave half of the population and force them to be incredibly industrious and work for basically nothing, the other half would live in absolute splendor. This would be a very efficient system, and think of the wonders we could create...
It may be more efficient (depending on how you define efficiency with regard to society) but does that justify it? Is that how the laws should be written?
If you have a problem with any brutal but supremely efficient system, it is because of morality. If you think that laws should be stifled from becoming too terrible on people for ultimate "gain", it is because of morality. Many people would find many problems with these laws because of general morality. While each individual person's morality is differing, there is a general sense of what is right and wrong. The laws tend to stick close to this. | 33 | 26 |
CMV: Indiana's "religious freedom" bill isn't as bad as people are making it out to be. | Just to set aside the "Religious Freedom" part of it for now, your main argument is that a business owner should be allowed to refuse service to a customer based on moral reasons, but doesn't that allow for discrimination based on race? If you replaced "gay" with "black" or "same sex marriage" with "interracial marriage" in your argument, would you still argue that it's not as bad as people say? Perhaps in this particular instance it may not have as much impact as people are saying, but it sets a terrible precedent for what excuses discrimination and for that reason it is just as bad as everyone says. | 17 | 30 |
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CMV: Most major socialist movements are driven more by hatred of the rich rather than a desire to help the poor | The theory that I have is that most major socialist movements in history (as well as many contemporary movements) are primarily driven by a loathing for the rich.
While many people call the USSR/China to be "not socialism", IMO the founding principles and ideas that drove the Russian Revolution and the Cultural Revolution are generally socialist, and a large swath of people generally believed and popularly supported in the ideals -- at least initially.
My argument is that "hatred of the rich" is a unifying element of nearly all socialist movements, and many socialist movements accrue critical mass most easily by fanning the population's hatred of the rich. Even though not everyone in a socialist movement may agree on exactly on how to implement a socialist state after the revolution, everyone agrees that the downfall of the rich must happen *now*.
And that's precisely what happened in the communist revolutions.
The rich were evicted from power / persecuted / jailed, but the movements largely fall apart due to a lack of universal consensus on how to implement a socialist state. Initial popular support crumbles after the 'enemies' are removed, and resentment rises against the controlling group because most people don't get exactly the kind of socialism that they wanted. The revolution deviates from the original vision due to practical reasons and it becomes a perversion of what most people would consider "socialism" in its purist form.
I genuinely think this is probably what would happen to most major socialists movements, particularly those that are driven by hatred of the rich. Even if a movement claims that it does not hate the rich, this notion sort of occurs incidentally by the nature of socialism itself (whether by the rhetoric used or other features of campaigning for socialism), and it's the most salient and popular feature of the ideology.
I think if socialism remotely has a chance to work, I think it should be primarily motivated by a communal desire and widespread cultural values to help the poor. Rather than investing energy into 1% protests (which IMO is strictly all about hating the rich; everyone including people at the 51% percentile should be actively helping the poor), we should proactively be pooling resources into community chests and and community organizations to help the least fortunate members of their own communities. We should be encouraging people regardless of their level of income (whether you are at the 30th percentile or the 75th percentile) to volunteer and contribute to helping the lowest percentile. | >We should be encouraging people regardless of their level of income (whether you are at the 30th percentile or the 75th percentile) to volunteer and contribute to helping the lowest percentile.
How would that lead to the workers seizing the means of production from the owner class? | 171 | 526 |
[Futurama] How did Leela and Fry move at all while time was frozen? | I mean they were able to walk on an ocean which means the molecules aren't moving. So how come their walking around and breathing like air is moving? things they touch don't unfreeze leela was able to spin a ball midair without it falling and she blew a snowflake forward. | They created a 'localized' field around them which enabled them to interact with objects such as air, water and such.
Strong enough to effect small things, not strong enough to work on people and organics.
Also, two points.
1. Spoilers alert!!
2. May as well be magic, didn't Arthur C Clarke say that any advanced technology would look like magic to this who didn't understand it.
So in regards to #2, the tech the professor invents allows a temporally 'stuck' person to engage with the world immediately surrounding them but not the larger world. | 108 | 150 |
ELI5: Why is the Freddie Gray shooting a "Black Lives Matter" issue when the only officer being charged with murder is Black, the city is mostly Black, the police force is mostly Black, the mayor is Black, the prosecuting attorney is Black, the president is Black, and the attorney general is Black? | The data that show racial bias among police officers does not show significant differences based on the race of the officer. It seems that black officers are just as likely to profile black men as white officers are.
As for the news coverage, the news is covering this mostly because of the aftermath, meaning the protests and the riots, and also because Ferguson was so recent. If this was just a killing with no protests and no riots, it may have had a couple of minutes on a news wrap-up just because this sort of thing is in the national consciousness right now, but other than that it wouldn't be covered outside of the local Baltimore media. | 1,020 | 1,703 |
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ELI5: How could a senior executive of a company sell any of that company's stock without it being insider trading? | There are two primary ways:
1) They have transactions arranged to sell at pre-determined times well in advance, for example they want to sell $250k worth of shares on the last day of every quarter.
2) There are "blackout" periods where insiders are advised that they are not able to trade. These are typically at the end of a fiscal quarter when executives become aware of financial performance, or ad hoc when there is a material event being discussed like an acquisition. The company's legal department will advise those "in the know" when they can/can't sell because the executive meets the criteria of having "material, non-public" information about the company. | 192 | 140 |
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ELI5: Why can you feel your pulse beating in a painful wound? | Inflammation is a big part of what causes pain. Inflammation also causes your arteries to constrict, raising blood pressure in the area. Higher blood pressure makes your pulse easier to feel. Up to and including perceiving it passively (typically as a throb). | 15 | 30 |
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What is the difference between a quantum and a photon? | Also, where actually does Boltzmann and Planck fit into the grand scheme of concepts like "The UV Catastrophe?" | A "quantum" of anything is just a small, indivisible, discrete piece of it. Something is "quantized" if it only has certain values it can take, like an electron in orbit around an atom.
A photon is a quantum of light. We think of light as being continuous, almost like a fluid, in our everyday experience, but on small enough scales, light can be thought of as particles. On those scales, there's no such thing as "less light" coming from something. It either gives off 1 photon, or it gives off no photons, but there is no in between.
Planck fixed the UV catastrophe (which was a problem with classical theories predicting blackbodies emit EM radiation with infinite power) by quantizing EM radiation. He posited that instead of treating light as continuous waves, you could treat them as particles of a particular energy - and doing so gives the *correct* equation for blackbody radiation.
Boltzmann didn't play a huge role in quantum mechanics - his contributions were mostly in statistical mechanics (and thermodynamics). However, a lot of his ideas from stat mech were applied to quantum systems later on. | 28 | 47 |
Statistical Tests vs bootstrapping | Hi, I recently read a statement along the lines of "if statistics were invented in the computational era, complicated statistical tests would never have been invented". The Statement then went on suggesting that bootstrapping approaches would have been used from the start.
How do you think this statement holds up?
Is bootstrapping straightly superior to classic statistical testing?
Could all statistical tests be replaced by bootstrapping? And if so, is this the future of data science?
I would also like some interesting literature regarding this topic, if anybody has some suggestions | Bootstrapping relies on you having a large and representative sample. If you apply bootstrapping to a small sample then you’ll get what appear to be amazing answers, but are probably very misleading.
Bootstrapping is a procedure that holds up asymptotically, just like other statistical tests. Bootstrapping is just easier, and can be implemented rather easily. Sometimes it can be better than other tests that have asymptotic properties, sometimes no. | 23 | 24 |
ELI5: if tornadoes occur nearly everywhere on Earth, why is it that the US has all the largest and most devastating ones? | Why aren't they as large in say Europe or Australia? Or anywhere else really. | Topography and location.
The US has a large flat area where cold air from the north can battle hot humid air from the south. These conditions create storms, and sometimes potent tornadoes.
The Arctic is a stones throw north of tornado alley, whereas the humid warm Gulf of Mexico is just south. As a result, they tend to collide, producing seriously potent storms.
Europe and other places don’t have this setup. There’s no gulf to provide highly humid and warm fronts in Europe, at least not where cold arctic fronts will collide with it. Mountains and landforms impede this exchange, which Europe has in abundance. Australia lacks the climate transition, and has strong topography to further restrict the issue. | 36 | 37 |
ELI5 Why are animals (and our old relatives) so small on the island of Flores? | Been wondering for a while why so many animals and our old relative the homo Floresiensis grew to be so small on this particular island. Is it to do with natural predators or maybe the food? Anyone have any clue? | The are two phenomena that often affect species that get onto islands - island dwarfism and island giantism.
Small species that get onto islands often leave large descendants. If they can arrive early with little competition and / or few predators then there's an opportunity for them to get much larger. There's a reason you get giant tortoises on multiple different islands.
Large species though often get smaller. Limited resources for a population of large animals means that selection for smaller individuals who need less food etc. means they tend to shrink.
Occasionally these can come together and you get the amazing phenomena on ancient Malta of giant swans with dwarf elephants (there's art online of this).
In the case of Flores, this tended to be dwarfism with things like miniature humans, and also today you can see the anoa (dwarf buffalo) but there are also giant extinct storks that lived alongside H. floresiensis.
TLDR limited resources means evolution selects for smaller individuals who can survive on little. | 37 | 18 |
If two self-driving cars are on the road next to each other, and their ultrasonic sensors are projecting the same frequency, would the data become muddled? How can the manufacturers account for this? | I work on the radar version. We use a few techniques to mitigate interference. One simple one is to randomly hop between frequencies. If you have, say, 1kHz of bandwidth that you can split into 1Hz steps, that's 1000 frequencies. If you randomly hop between them, the chances that another sensor will happen to intersect for, say, 5 consecutive transmission periods becomes tiny (10^-15). You were going to average across many transmissions anyway, to average your way through noise and so on, so it's a cheap way to become robust.
By the way, I've heard that manufacturers used to bring their devices to conferences so that everybody could test interference mitigation against one another. Doesn't seem to happen any more, at least for automotive radar. | 486 | 846 |
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Is it true you cannot master a language (speak like native) after around a certain age? | I heard this a few times but think it is false. Does this limitation really exist and is it really that hard to overcome? | You can master a language pretty well after the age of 10 or so, but studies have proven that you will [almost] always make small mistakes in grammar and have a slight accent, and be less likely to pick up subtle grammar misnomers.
It is also harder to pick up a language after this age, but it is still possible with study, concentration and immersion. | 16 | 30 |
CMV: Prostitution should be legal | Prostitution is the world's oldest profession. It's never going to stop, as long as poverty exists, it will exist. It's better to legalize it, regulate it and make it safe for women who partake in it.
A grown woman can choose to do whatever she wants with her body. It's *her* body.
The fact that it isn't "Christian" or comports with certain religious points is unconvincing. Pornography doesn't comport with religious views, yet it is legal. Stripping doesn't comport Christianity, etc. but it's still legal.
Additionally, if it's legal for a woman to have sex with a man on camera for money, why is it illegal for a woman to have sex with a man off-camera for money? I see no difference.
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> *This is a footnote from the CMV moderators. We'd like to remind you of a couple of things. Firstly, please* ***[read through our rules](http://www.reddit.com/r/changemyview/wiki/rules)***. *If you see a comment that has broken one, it is more effective to report it than downvote it. Speaking of which,* ***[downvotes don't change views](http://www.reddit.com/r/changemyview/wiki/guidelines#wiki_upvoting.2Fdownvoting)****! Any questions or concerns? Feel free to* ***[message us](http://www.reddit.com/message/compose?to=/r/changemyview)***. *Happy CMVing!* | How are you going to combat human trafficking and ensure that those who participate are actually doing so of their own free will? Even if it is legal it could easily create a huge front for human trafficking. The people who are trafficked are threatened and have their family threatened regularly. Legalizing it won't change this as a possibility. | 124 | 754 |
Is there a difference in brightness between a light source emitting one colour and a light source emitting the same amount of photons but white? | If you are referring to subjectively perceived brightness, then there can certainly be a difference in brightness between a monochromatic light source and a white light source emitting equivalent numbers of photons. If the wavelength of the monochromatic source is around the peak of human sensitivity, around 555nm, then it would appear brighter than the white light source. Conversely, if the monochromatic source is emitting a frequency that is not well absorbed, then it would appear dimmer than the white light. | 40 | 102 |
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Our manuscript got rejected but they offered to transfer it to other journals? | My supervisors and I submitted a manuscript to a journal. Our manuscript fit the scope but judging from their recently published papers it was clear that they favour another method and only every now and then publish papers with the method we used. We wanted to try anyway (they have a good impact factor) and got a rejection today with the offer to transfer the manuscript directly to a variety of other journals.
What I am wondering now is: does it make any difference whether this journal directly transfers the manuscript or whether we take the manuscript and submit it to a journal by ourselves? Which of the two is the better option? | The main advantage with these trickle-through systems is that it saves you having to jump through formatting hoops.
So, the only reason to trickle down is if the paper they are sending it on to is if it is the next on your taget list. If your next target journal isn't in their publishing house, or the next on the trickle-down list, then go elsewhere. | 88 | 74 |
AskScience AMA Series: We are three math experts here to tell you about our projects and answer your questions. Ask Us Anything! | We are three math panelists working on a variety of things. Our projects are listed below, along with when we'll be around, so ask us anything!
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/u/dogdiarrhea (11-13 EDT, 15-17 UTC) - I'm a master's student working in analysis of PDE and dynamical systems possessing a "Hamiltonian structure". What does that mean? Dynamical systems means we are looking at stuff that evolves with respect to a parameter (think an object moving with respect to time). PDE means that the thing we are describing is changing with respect to more than just 1 parameter. Maybe it is a fluid flow and we also want to look at how certain properties change with respect to their position and their speed or momentum as well. Hamiltonian structure is a special thing in math, but it has a nice physical interpretation, we have a concept of 'energy' and energy is conserved.
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/u/TheBB - (12 EDT, 16 UTC) - I did my undergraduate education at NTNU in Trondheim, Norway (industrial mathematics) and my Ph.D from 2009 to 2013 at ETH in Zurich, Switzerland, on function spaces for the discretization of kinetic transport equations. For the last year I've been working at a private research institution in Trondheim, where we do simulation work. The most significant recent project I've been working on is the [FSI-WT](http://www.fsi-wt.no/), where we've been doing fluid-structure interaction (FSI) simulations on wind turbine blades.
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/u/zelmerszoetrop (15-17 EDT, 19-21 UTC) - I studied general relativity/differential geometry in undergrad and start of grad, switched to number theory in graduate school (dramatic turnaround!), and then did a second dramatic pivot by going into data science when I left academia. A current project I'm working on involves reconstructing a graph (as in, a set of nodes and connections between them) with deleted edges after training on other, similar graphs (with the right definition of "similar").
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A question for /u/zelmerszoetrop , in particular.
How did you background at undergrad/grad level affect your current work. Did you have to go through relearning in the data science sector?
How can ideas in pure math (related to your background) be applied to machine learning type questions?
Is it possible to work on such problems while remaining in academia?
| 17 | 376 |
ELI5: Why does the concrete not seem to be cracking, crumbling, or disintegrating when a skyscraper or a bridge swinging or wobbling in the event of an earthquake? | Concrete is famously quite weak in tension, i.e., it doesn't bend. But what can bend are the spaces between concrete panels and pillars. When you see video of a bridge bending and flexing, it's able to do that because it has been designed to be able to do that, with flexible joints between the concrete members. On the other hand, a building swinging or wobbling might well be vibrating beyond what its design can handle. In that case, you might not see visible cracks forming, but micro-fractures are likely forming throughout the material that could lead to collapse. This is one of the reasons we add steel rebar to concrete - steel is a lot better in tension and will hold the mass of concrete together even if some micro-fractures and cracks form in it. | 202 | 244 |
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What exactly is a photon? | I'm a bit embarrassed to ask this question. I sort of know what photons do but not exactly what they are. Where do they come from? How are they created and what particles are they made up of? | Photons are little disturbances/ripples that move around the electromagnetic field. This electromagnetic field fills all space, and it is stronger near things like electric changes and magnets. Because this field obeys quantum mechanics, the ripples carry discrete properties that can only be certain numbers. This makes it very different from things like water ripples in a pond. This is what we mean when we say something is 'quantized.' They are created when charges move or change configuration. Some examples of this would be the light given off by light-bulbs when you run current through the wire, when you bounce two electrons off each other and when an excited atom relaxes to a lower energy field configuration generating a photon.
Photons are, as far as we know, not made up of anything else. They are their own particle which is fundamental. They also do not have mass, but they do have energy and momentum. | 73 | 165 |
CMV: I don't believe I should pay a tip based on a percentage. | Surely if I buy food the service should be the same on a $30 meal as it is on an $100 meal. The value of the meal is irrelevant in the same establishment.
For example, I could buy a ton of food in a rubbish place and have to pay a larger service tip than if I bought less food in a much nicer place in which the service I received was a lot better.
Using a percentage of the cost of the meal does not make sense as the service quality should be a constant and doesn't increase proportionally to the cost of my meal. Please, CMV.
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> *Hello, users of CMV! This is a footnote from your moderators. We'd just like to remind you of a couple of things. Firstly, please remember to* ***[read through our rules](http://www.reddit.com/r/changemyview/wiki/rules)***. *If you see a comment that has broken one, it is more effective to report it than downvote it. Speaking of which,* ***[downvotes don't change views](http://www.reddit.com/r/changemyview/wiki/guidelines#wiki_upvoting.2Fdownvoting)****! If you are thinking about submitting a CMV yourself, please have a look through our* ***[popular topics wiki](http://www.reddit.com/r/changemyview/wiki/populartopics)*** *first. Any questions or concerns? Feel free to* ***[message us](http://www.reddit.com/message/compose?to=/r/changemyview)***. *Happy CMVing!* | A) The "amount" of service received scales with the amount of food you buy, serving you a first course, second course, entree is obviously more work than just serving one course.
B) The service is proportionate to the quality of the food. High quality establishments generally have a higher employee to customer ratio to ensure more attention.
Any method of determining the tip is not going to be 100% representative of the effort the server put in, but percentages tend to average out. Somedays you get 20% on two cups of soup that you did the whole high class service spiel on who also wanted extra lemons, extra sugar, approximately eight pieces of bread, had their credit card declined and demanded refills on everything for the next two hours while they sat and chatted. Other days you say hi, they pick out a 150$ bottle of wine, salads and high end dishes before you really say anything and you get 20%. Most tables are somewhere in between though. | 11 | 21 |
Can anyone explain stem cells LI5? | Every cell in the human body has a specific job. For example, the cells that make up the human heart perform a specific function, they make up the organ and pump blood through the body.
A stem cell is a cell that hasn't been assigned to do any job yet. So, what you can do with a stem cell is assign it to do a specific job of your choosing. So, lets say that you need a new heart. Doctors could take stem cells and grown you a new heart that is 100% compatible with your body as if it was grown in your body.
That's a very basic explanation of what a stem cell is. | 12 | 24 |
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Is their a math question that should make sense on paper but is actually impossible? | * Finding analytic solutions to polynomial equations of order greater than 4.
* Squaring the circle - constructing a square using only straight-edge and compasses that has the same area as a given circle.
* Trisecting an angle - constructing an angle using only straight-edge and compasses that is one-third the size of a given angle. | 35 | 31 |
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Is there such thing as a cytotoxic memory T cell and if so what is it’s role? | I haven’t been able to find a definitive answer from google but I was just wondering is it a thing? I was under the (very possibly wrong) impression that there are only cytotoxic T cells and memory T cells. | Cytotoxic T cells are defined by their expression of CD8 in contrast to the CD4 ecpressed by the helper T-cells. After developing a functional T-cell receptor and undergoing selection, cytotoxic T-cells are in a naiive state and have to come into contact with an corresponding antigen. When they do, they differentiate into one of several different activation states including the cytotoxic effector and cytotoxic memory T-cells. The effector T cells have the highest cytolytic function but are short lived, while the cytotoxic memory T-cells are there to perserve the "memory" of the antigen. They are longer lasting and are able to rapidly proliferate and differantiate into the effector cells upon renewed contact with the antigen. | 233 | 767 |
ELI5: Why do different European languages have such varying names for Germany? | Allemagne, Германия (Germaniya), Saksa, Deutschland, Germany, etc. | The origin of the name for Germany in a certain language depends on that country's one time relationship with Germany.
Allemagne, Alemania (Romance languages) -- comes from the Alemani tribe of Germany.
Germaniya, Germany, Germania -- that is the name which the Romans used for the territory north and East of the Rhine.
Saksa -- Finnish, named after the Saxons, yet another German tribe.
Deutschland, Duitsland -- this was yet another German tribe which became the word for the whole country. | 1,663 | 2,302 |
If a cloned organ starts off as "old" as the original cells used for the cloning and with the same accumulated damage to the DNA and shortened telomeres, then shouldn't we be preserving our DNA as soon as possible? | Wouldn't that ensure the "youngest" possible cloned organs for ourselves when the technology becomes viable in the future to extend our lives in such ways?
In other words, let's say I am in my 20's now, wouldn't I want to preserve my DNA as soon as possible so that if the technology to clone your own organs becomes viable in the next 40 years, then when I'm 80 with liver failure I can have a "younger" liver regenerated using my 20-year-old DNA rather than an "older" liver regenerated using my then 80-year-old DNA?
Could stem cells help mitigate the above? | Theoretically that would be ideal as your DNA will have accumulated less mutations. A mutation in a part of the genome that a tissue doesn't use has no effect but try using that DNA to recreate another tissue, you might run into a problem
Couple options would be to preserve when younger. Another would be to take a few samples of various tissue in respect to what you want cloned
As for telomeres, although we don't have the natural ability to regenerate our end strands, plants do. It's not farfetched to think you if you're able to clone a tissue, you can use plant enzyme/ insert the gene to add that function. It's one of the reason we age, while oxidative stress is another primary factor (plants are much better at neutralizing super oxides then we are)
These possibilities will come from more somatic stem cell research which faces it's own technical and funding problems vs embryonic stem cell research which is more of a ethical problem holding it back.
| 20 | 191 |
ELI5: What is the Gaia Theory? | Gaia Theory is simply that you can study the entire earth as if it were a single organism. All life and non-biological substances on the planet react to each other, and evolved in such a way that they are impacted by each other. As such, you can study large scale changed to the earth (both the biological and non-biological parts) as all part of a complex interworking system, the same way you might study one of the complex systems in humans (such as the Krebs Cycle).
At times it has be criticized because proponents have a tendency to act a little bit too much as if the Earth actually is a living organism, and it's sometimes used by people in a pseudoscience way, but there is good science around the theory. | 77 | 126 |
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ELI5:Why can't we divide by zero? | If mathematicians invented the imaginary number system to make it possible to find the square root of a negative number, why haven't they figured out something similar for dividing by zero? | Think of division as putting something into groups. If we have 10 blocks, and we divide them into 5 groups, there are 2 blocks in each group. If we wanted to do 10 / 0, that would be taking 10 blocks and putting them into zero groups. | 23 | 17 |
[Star Wars] Why were Jedi chosen as military generals? Was mass tactical combat a part of the Jedi training? | Going through Clone Wars, it seems every major Jedi had some mid or high-level role in the Republic army. Why? | The Jedi's aptitude for the force is actually a major strategic advantage. Some Jedi posses a talent for a technique known as Battle Meditation, which can help determine and change the flow of the battle.
Beyond their aptitude for that unseen, they are there because to the republic it is important that they *be* seen. Watching a Jedi fight is an amazing sight and a huge boost for morale. The presence of the Jedi reinforces in a Republic Soldier's mind that they are doing the right thing. Fighting for the side of the light can be a powerful image. | 43 | 39 |
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