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nstvwu | How does this optical illusion work? | URL_0 | Other | explainlikeimfive | {
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"It takes more time to see something dark. You move the picture. First the bright appears where you put it, then the dark gets visible. Also the Hard borders. Great contrast there. So easy and fast to process. The ol‘possum isn’t as rich in contrast. So more time to process.",
"The pixeled area messes with your peripheral vision and your eyes try to adjust. Make a binocular with your hand. look through it at the possum with the pixeled area blocked out. You will notice the possum stops moving funny."
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nsunfh | I heard that it is incorrect to say that i = sqrt(-1) but it is better to say that i^2 = -1. Why so? | Is it because (-i)\^2 also equals -1? | Mathematics | explainlikeimfive | {
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"They're both true, but the second one is the definition of i. We define i by noting that x^(2)+1=0 \"should\" have two solutions and choosing to call one of those solutions i. From there we can define sqrt( & minus;1)=i, rather than defining i=sqrt( & minus;1). We also find that the other solution of x^(2)+1=0 is equal to & minus;i. There was nothing special about the solution that we picked before we picked it - we didn't say \"let i be the positive solution\" or anything like that. Instead we said \"let i be one of the solutions\", then effectively decided to call whichever one we picked the \"positive\" solution.",
"They probably say its better to say it as i^2=-1 because that is how i is defined. The sqrt thing is simply the reason we defined i this way.",
"Kind of. Both *i* and *-i* satisfy the definition equation: > x^2 +1 = 0 which has two distinct solutions. So how do we know which is the positive solution (*i*) and which is the negative one (*-i*)? The answer is that it *doesn't matter*! There isn't any meaningful difference - they are quantitatively different, but algebraically identical. If you take any mathematical proof or theorem involving *i* and switch them all to *-i* everything still works. Which one we take to be the \"positive\" one is arbitrary - we get to pick one to be the positive, and then the other becomes the negative. But everything works fine if we picked the other to be positive (kind of like how when defining angles you get to pick whether they are measured clockwise or anti-clockwise - traditionally in maths we use anti-clockwise, apart from when taking bearings when we take clockwise to be positive). So we *could* define i = sqrt(-1) or i = -sqrt(-1), but that is unnecessarily limiting. i^2 = -1 is the more general statement, and in maths generally we prefer more general statements.",
"There's a technical explanation that I haven't seen any other comment to mention. It's kind of hard-ish to ELI5, but I'll try to illustrate it by giving a hypothetical discussion between two mathematicians, Alice and Betty. * Alice: Now I take the square root of -1. * Betty: What? As far as I understand we defined what the square root is only for non-negative numbers. * Alice: I define a new number i, which is the square root of -1. * Betty: Okay, square root of -1 is now something called i. Now what? * Alice: Now i^2 = -1. * Betty: Why? * Alice: Because the square of a square root is the original number. * Betty: That is indeed true for non-negative numbers. But why would it be true for your i? It'd be like saying that your i is non-negative since all square roots before were non-negative. * Alice: Oh yeah. So could I try to somehow figure out that i^2 = -1? * Betty: You have not ever said what it means to multiply i with itself. Your i^2 carries no meaning. * Alice: So I guess I just have to define i^2 then? * Betty: I guess so. * Alice: Okay, I then define that i^2 is -1. * Betty: Right, and that definition does make it kind of consistent with the square roots we had before. Okay, what next? The point the above imaginary conversation should get across is that saying that i is the square root of -1 is not useful at first. You also immediately need to define that i then obeys some of the standard computational laws of the square root, most likely including that its square is -1. So giving the square root definition pretty much forces you to give the i^2 = -1 definition also afterwards if you want to get anywhere. On the other hand, if you start from i^2 = -1, you can get really far into the theory of complex numbers without ever having to talk about the square root of -1 -definition."
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nsuxmx | Would wearing multiple hazmat suits protect you from more radiation? | Would multiple suit layers give you more protection or would it be the same as wearing one suit? | Physics | explainlikeimfive | {
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"Not really. The suits don't keep out ionizing radiation, which is the major problem. It does stop radioactive particles getting in, so you don't get any radioactive materials on your skin or in your lungs, which does help a lot. One suit will keep them out completely, so you don't need more than that. But the radiation itself still goes right through.",
"The protection a hazmat suit provides to radiation mostly comes from preventing contamination by radioactive material. Alpha and beta radiation is fairly easily stopped by air and skin, and gamma radiation isn't really going to be reduced unless your hazmat suit is made of lead plates. Adding more suits won't really increase protection against contamination unless the original suit has failed quite badly."
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nsvb9d | why does .999999 with the 9 repeated infinite times equal 1? | I saw the proof on how .9999 equals 1 in mathematical terms, but my brain still struggles with it. Why? And does 1.99999999 repeated infinite times equal 2? | Mathematics | explainlikeimfive | {
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"How do you represent 1/9 in decimal form? .11111111 repeated. So if you assume that those two are equal... 1/9 x 9 = 9/9 = 1 .11111(repeating) x 9 = .99999(repeating) .99999(repeating) = 1 This only holds true due to the opening assumption.",
"Without getting too far into the maths, two numbers are different if there is some difference between them. So if you take them away from each other you get something other than 0. Similarly, if two (real) numbers are different then you can always find another number between them. If we apply either of these tests to 0.99999... and 1 we get the result that they must be the same; there are no numbers between them, and if you take them away from each other you get 0. To do this properly we need to be really careful what we mean by \"...\" or \"an infinite number of 9s.\" But that's a bit beyond ELI5.",
"People have already posted proofs and stuff, and you said you’ve seen it already anyway. But as for the ‘why’, it’s just because of limitations in the way we represent numbers. We use a base 10 number system, so we have 10 different characters before we have to start repeating. The problem is that 10 isn’t divisible by everything. Divide it by 3 and you get weird results that don’t fit nicely. That doesn’t change the reality though. Hours and minutes are a good example. They’re base 60. One third of an hour is exactly 20 minutes. You can break it into thirds no problem and there’s no weird decimals that don’t make intuitive sense. So it’s not like thirds just can’t work no matter what, but when everything is based on 10 it just doesn’t fit neatly is all. We’re used to different characters representing different and unique things, so we want to think 0.999 is different than 1. But it’s not. Numbers are just more complicated than letters and sometimes we just have more than one way to get to 1 that we can’t represent quite right. So we have two different things that equal the same value.",
"The common block is that you're likely imagining the infinite series of nines as merely a really long string of nines that stops eventually. That's not an infinite unending series of nines, though. Any string of nines that ends is **not** equal to one. Here's a few different ways to think about it. There's no difference between them. I mean that in a mathematical sense of \"the answer to a subtraction\". The number one minus an increasingly longer string of nines is an increasingly long string of zeroes with a one at the end. When the string of nines is infinitely long, the string of zeros is infinitely long, so 1 - 0.9999... = 0. That's the additive identity, so they must be equal. There's nothing between them. If you have two different numbers, you can always name one between them. That can't be done. There's no end to the series of nines to stick another number to make it bigger, and none of the nines can become a larger digit. So there's no in between number, meaning they must be the same. Finally, does 1.999... = 2? Sure does! |1.9999... = 2 Let's break up the 1.9999...| |:-| |1 + 0.9999... = 2 But 0.9999... is one, so| |1 + 1 = 2| |2 = 2|",
"There are a few ways to approach this. First consider that we can always find a number between two different real numbers, so 0.9 and 1 have 0.95 between them, 0.99 and 1 have 0.995 between them etc. If two numbers are different, we can always find a number which is between them. Then consider 0.999... and 1, there is no number between them. You can't add anything to the end because it's an infinite sequence of 9's, if there is no number between them then they must be the same number. Alternatively consider that 1/3 = 0.33..., 2/3 = 0.66..., 3/3=0.99... but also 3/3 is just equal to one.",
"The simplest mathematical explanation is to recognize that 0.999... is an infinite series. That is, it can be represented as 9/10 + 9/100 + 9/1000 + 9/10000 + .... There is a special type of infinite series in mathematics called a [geometric series]( URL_0 ) that is of the form 1 + r + r^(2) \\+ r^(3) \\+ .... We can make 9.9999... look like this by setting \"r\" to \"1/10\" and writing it as 9(1 + 1/10 + 1/10^(2) \\+ 1/10^(3)...), which will of course give us 9 + 9/10 + 9/100 + 9/1000.... To make 0.9999..., we simply subtract the first 9, so it'd be -9 + 9(1 + 1/10 + 1/10^(2)\\+ 1/10^(3) \\+ ...). A geometric series converges at 1/(1-r), as is demonstrated on the linked page. So for r=1/10, the series converges at 1/(1-1/10). Plug that into our representation, and we get -9 + 9(1/(1-1/10)). 1-1/10 is of course 9/10, so this simplifies to -9 + 9(1/(9/10)) which simplifies to -9 + 9(10/9) and then -9 + 10 = 1. However, this relies on concepts generally taught in calculus classes, usually after differentiation and integration (so Calculus II or III depending on how the school divides material.) So while this is mathematically simple, it is not conceptually simple for people who have only studied arithmetic and algebra. I think the simplest conceptual explanation is to recognize that 0.111.... = 1/9, 0.222.... = 2/9, 0.333... = 3/9, etc. and that 0.999.... = 9/9. This is not a *proof*, but it does help make it more intuitive."
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nsvck2 | Why do humans have such a hard time swallowing or things "going down the wrong tube" relative to animals? | I feel like quite often in the span of a year I choke on water or something going in my airway. I've never witnessed an animal have the same problem. Is this a problem unique to humans, and if so, why? | Biology | explainlikeimfive | {
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"\"Humans are the only mammal that cannot breathe and swallow at the same time, and we are the only species that can choke on its own food. The reason? The lowering of the voice box in our throats (during infancy) enables us to create the enormous range of sounds used in producing language; but this lowering of the voice box comes at a big cost in adulthood.\" URL_0",
"Well, I’m humans the tube you eat/drink from happens to sit right next to the one you breathe from, and the only thing that stops food going down your airways is a small ‘flap’. So, obviously, if it isn’t timed right, some thing can actually go the wrong way. Other animals airways and throats are structured differently. Our voice box moves during our life, which means our throat changes. Other animals don’t tend to do this, so they can breathe while they eat There’s also the case of actions. Animals usually just eat, but a human might be talking, or watching something by they find funny, so there’s more opportunity for things to go wrong"
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nsvxi8 | why after a thunderstorm does the air not feel as stuffy and has ‘cleared the air’ so to speak? | Physics | explainlikeimfive | {
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"At least one explanation is that air generally has tons of dust particles floating through the air that you are constantly breathing in, but when it rains those dust particles are hit by the water, dragged to the ground, and prevented from floating around until its dry again. So it’s like the storm acts as a giant air filter."
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nsw8zo | For those of us with horrible allergies: How does the body not run out of snot? Eventually, you'd have to dry out, right? | Biology | explainlikeimfive | {
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"Snot, like most things made by your body, is mostly water. When sick or suffering from hay fever, your body starts consuming extra water to produce mucus and snot. It absolutely is possible to get dehydrated because of this. If you've ever heard someone tell somebody with a cold that they should make sure to drink plenty of fluids, this is partially why.",
"Only if you stop drinking water. It's not like you have a snot tank that will run dry. Your body just produces more.",
"You do run out but not until you dehydrate. If you get that dehydrated tho you have a much bigger problem than allergies."
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nswaic | What's that feeling when you learn/hear a new word for the first time and then start seeing/noticing it everywhere? | For example, let's pretend I get lost in a rabbit hole of geometry and wound up learning a new word, 'oblong'. Then I start seeing it in news articles, on TV, papers, videos, signs, in conversations, the internet, books; everywhere! The feeling wears off in 2 weeks or so. Obviously, I know it must be psychological, but how and why does this happen? Is there a name for this effect? | Other | explainlikeimfive | {
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"The Baader-Meinhof phenomenon is actually a term for 'frequency illusion', a type of cognitive bias your mind creates. To understand this, you need to know a little about cognitive bias as a whole. Though there's a whole lot of nuisances caused by cognitive bias, in short, it’s when your mind deviates from normal, rational thought and starts to make up patterns based off of nonsense. …frequency illusion is, in fact, two different processes happening at the same time: selective attention and confirmation bias. The first process, selective attention, comes about when you learn anything new. Basically, when you learn something new, it stays fresh in your mind - you’re paying more attention to it than other things. Because of this, you see it more often when going about your daily life. However, this very simple, logical process is amped up by confirmation bias, which is a cognitive bias that makes you \"search for or interpret information in a way that confirms one's preconceptions, leading to statistical errors\", reports ScienceDaily. This means that your mind is on the look-out for newly learned information because it’s still super fresh and interesting to you. At the same time, your mind sees these new words everywhere, thinks that it's weird, and tries to make it fit into some rational system. In other words, because the information is new, you suddenly force yourself to believe that it's new to everyone and has suddenly popped up, when in reality, you’ve just stopped ignoring it. You actually see new words more often and believe there’s some weird pattern at work because your mind is trying to make sense of new information. It just so happens that most of it is made up. - [article]( URL_0 )",
"Baader-meinhof phenomenon. AKA the frequency illusion. You can read the Wikipedia page for it, but it's almost exactly what you described, just in different words. But, for example, after buying a Nissan altima, I started noticing the same make/ model everywhere I go."
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nsxf0g | Psychology - Munchausen's Syndrome | I've seen accounts of Munchausen's in which a caretaker, usually the mother, causes illness or harm to her children to gain attention/sympathy. But what about a mother who causes emotional distress and maligns the child to all who will listen - and receives lots of pity and commiseration about their hopelessly horrible child who does all sorts of terrible things? Also sets up scenarios dangerous to the child and then tells everyone the child did it themselves. Is this a form of Munchausen's or some other disorder? | Other | explainlikeimfive | {
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"Anyway you’re actually talking about munchausen’s by proxy, which is a different disorder with different causes. But generally, no, the second thing is straight up child abuse (and there’s moves to reclassify munchausen’s by proxy as child abuse as well). Not all crimes are mental illness. Some people just like attention, whether it’s because they have a mental illness or not.",
"Not a psychologist but you're probably looking for Munchhausen by proxy. The Baron of Münchhausen is hero of several German folk stories, that are over the top nonsense, like pulling oneself out of a swamp by his own hair (apparently the origin of the bootstraps thingy), riding a canonball or stuff like that. Which gave him the nickname of the lying baron. That was then used as a description for people who make up illnesses or causing them to themselfs and when they do it to other people it's called \"by proxy\"."
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nsxu09 | Why we should pay tax for our purchase if we already pay tax for our salary | Economics | explainlikeimfive | {
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"Why should we even pay tax on our salary? Or on property. Or capital gains? We can keep asking this but eventually the answer is because the government needs money from somewhere and they(unfortunately sometimes) get to decide where that comes from. Sales tax is also usually a local tax where as income tax is at the state and federal level."
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nsxwsw | Why does bathroom sink water seem to taste different than kitchen sink water? | Chemistry | explainlikeimfive | {
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"Measure the temperature difference of the first 20 seconds of water. That can make a huge difference to taste. Ground water is often cooler than the extra house piping needed to reach the bathroom. Aerators often found in bathroom taps to prevent splashing change the taste too (and get gross, they need removing & cleaning). Your kitchen faucet probably cost twice as much as the bathroom fitting, and is more likely to use ceramic valves and noble metals that don't impart a bad taste. As the most frequently used faucet it will hold fresher water too.",
"In UK houses of the past, kitchen cold water came direct from the rising main, as we called it. Direct from the water supply coming in from the street. It is almost always running water, on the move, so it's fresh, not stagnant. The bathroom typically upstairs, would routinely be supplied from a cold water tank, typically in the attic space. This was water that had been standing around for ages, and was not regarded as drinking water. Fine for washing, bathing, flushing, but only suitable for spitting out once you'd brushed your teeth. You may have a similar arrangement, without a description of your plumbing, nobody can say.",
"Your kitchen sink faucet likely has an aerator and your bathroom tap likely does not. I would imagine the microscopic air bubbles added to the water explain the change in taste.",
"Short answer, because no legal or regulatory body or plumber is there to make sure your bathroom water is fit to drink from, and in fact the kitchen tap is the only point that you are supposed to get supplied with food-grade water. In the UK the cold kitchen tap (CKT) will tend to be the point of entry into the property, therefore going through the least internal pipework, and will be the designated drinking point. The mains will be cooler and have a higher level of chlorine. The regulations on mains systems are in place to ensure water is transmitted over long distances without losing its wholesomeness. Internal systems may not be to the same standard. Most changes to taste and odour (t & o) will be either plumbing materials imparting a t & o, or will be geosmin. Geosmin is the chemical responsible for earthy/musty/stagnant t & o, also what gives rainfall on a warm summer's day. It will be a consequence of environmental organisms and fungi that grow in internal pipework- itself due to warming, plumbing materials, and stagnation. Stagnation allows for warming to increase, and for chlorine levels (chlorine being a gas which dissipates over time) to drop. This process of 'stuff' growing is called regrowth, because tap water is not sterile, and things and start to grow when given the opportunity. There may also be more active issues such as backflow from appliances. Generally, it is not advisable to drink from non-ckt points as you cannot be certain of its parameters. Water is (in the UK at least) designated as a food product FROM THE COLD KITCHEN TAP- once it is not from the CKT it is then subject to internal systems and will carry with it the assurances that it would otherwise. It would not be anyone's regulatory or legal responsibility, for example, to ensure that water is wholesome and fit to drink. That means internal plumbing is designed to follow that, too. Walk further to the kitchen, and run water till it's cool(er).",
"Set up a blind taste test. Maybe it's psychological?",
"There should be no difference in the water itself since the source is the same (municipal water coming through your hot water tank) so I'm going to submit that you could have plastic (PVC) piping in your bathroom and metal (copper or old black pipe) in the other- or vice versa. Water piped primary through metal will often have a metallic taste while PVC piped water has none.",
"It shouldn't, unless your kitchen has a hard water faucet. Not all kitchen sinks do, but some have an extra faucet on the side that only puts out cold hard water that hasn't gone through the water softener. That is what we used as drinking water as it tasted better than softened water and is apparently better for you because of the trace minerals as long as the well water doesn't have anything bad in it.",
"Interesting. I always thought the bathroom water tasted better. (Raised in the states, New England)",
"You might have a water tank in your loft that supplies water to your bathroom, whilst your kitchen gets its water from the mains.",
"It's in your head. Unless your pipes are set up to alter water going to your kitchen (eg: reverse osmosis), it's the exact same and comes from the same source. I get water from the bathroom faucet all the time and there's quite literally no difference.",
"If you have a water softener it will only services the bathroom sinks and water heater, the kitchen sink will bypass the water softener. You may have hard water coming out of the kitchen faucet which would change the taste.",
"It might have something to do with the fact that 80% of your tastes comes from aroma. Since there are different \"aromas\" (Kitchen: Food, Oil, Coffee, etc. Bathroom: Cleaning products, shampoo, soap, etc.) in your bathroom compared to your kitchen the water might taste different even if it's coming from the same pipe. That's the most likely i can think of it might be entirely wrong though 😅"
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nsyeb2 | My headphones "broke" and now I don't hear lead vocals anymore and the sound quality is really bad - Why? | This is the 4th time any of my headphones "break" like this. It's really fascinating hearing the background vocals and...basically everything that's normally "hidden behind" the lead vocals of my favourite songs. | Technology | explainlikeimfive | {
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"Your cord / connector is fucked. It's a stereo-mixing thing - the voice is usually exactly centre, and the music is around the edges. Your ground connection has broken, so it's effectively subtracting one channel from the other - filtering out what's common, and only playing what's different. If it's possible to replace the cord, your headphones themselves should be fine. If not, make sure your next headphones use a separate cable, rather than a hardwired one. Then when this happens next time, you just go buy an aux cord. (some brands use stupid small-diameter sockets; gotta watch for that)"
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nsyn4f | What is 4D chess? | I've heard this term a lot online this past year and even looked up what it means, but I'm still confused about it. Maybe someone can explain it to me better. | Other | explainlikeimfive | {
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"3D chess is considered to be a much more complicated version of normal chess. It takes a normal chess board and adds layers to it above and below for pieces to move to. While it may not be necessarily be the case, it is stereotypically considered to only be playable by those with very high intelligence due to the complexity of the game. 4D chess is a continuation of that idea, either by utilizing multiple 3D chess boards or by somehow incorporating time as the fourth dimension. 4D chess does not actually exist as a physical game to my knowledge, but when people say that someone is playing 4D chess, It means that they are being incredibly intelligent in planning out their strategies in whatever they're doing. Many times, It has been said that world leaders are playing grand game of chess when they maneuver armies while at war, this is just stating that the person is thinking even further ahead than that.",
"While 3D chess is an actual game with rules, it became part of popular culture after a variant of it “Tri-Dimensional Chess” was featured in many Star Trek episodes, with Spock usually winning. This established the notion that playing 3D chess requires a high level of intelligence. 4D chess is taking that and turning it up to 11. There is no such game but someone “playing 4D chess” is involved in a complex process that requires a lot of intellect."
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nsyzyf | How did they do color correction/color grading on film (before they used computers)? | Technology | explainlikeimfive | {
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"They didn’t really. You could control the RGB values by adjusting the printer lights. But no grading in the sense of how we do it today. Different kinds of film had different looks to them though. And lighting is a big aspect of how a film looks."
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nsz14h | What can I do, as one man, to clean the ocean? | Earth Science | explainlikeimfive | {
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"Extra: I understand that this is probably not the best place to post this question, as it's probably got lots of big answers. But I don't really do reddit or much of the Internet even, and I just want to do my bit. Any help is great. Thank you"
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nsz2ap | How do free mobile games make money when all the ads are for other games? | I understand they make a little bit on people who buy the ad-free versions, but it seems like a closed ecosystem to me where the games all spend all their money buying ad spots on other games. What’s the business model? | Economics | explainlikeimfive | {
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"So one way a lot of “freemium” games work is by utilizing the marketplace for ad placement. In a lot of mobile games you have pop-ups which the game’s producing company will sell spots for other companies to advertise to the player-base in. By selling these ad spots the game producers make tons of money while still being able to provide a free game. Also a lot of them supplement in micro transactions for ad placement, such as fortnite with V-bucks."
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nszno8 | Are cravings based on a persons deficiencies? | For example: Does the brain find potassium rich food more appealing compared to other food when you have a potassium deficiency? | Biology | explainlikeimfive | {
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"in theory, yes. this is suggested with a few things: chocolate craving has a suggested nutritional connection with magnesium deficiency ice chewing as a symptom of anemia, suggested as a result of physical deficiency craving \"comfort foods\" is suggested to be related to dopamine deficiency none of this has been \"proven\" per se, but it is a commonly-agreed-on hypothesis.",
"Does your body know which foods are rich in potassium? How could it? In order for deficiencies to trigger cravings of specific foods, your body would need a mechanism to signal deficiency, and a way to connect that deficiency to specific foods. Your body doesn't know that bananas are rich in potassium, your brain does. Your brain only knows because someone told you. There is no feedback loop for your body to know that bananas specifically are what you need. If you were a human in the wild, and didn't learn that bananas are high in potassium, then how could you possibly know to crave bananas? There are symptoms of potassium deficiency that you would certainly experience, but no mechanism for your body to know that bananas can address that. As another example, consider that many people who menstruate are deficient in iron. These people should be craving iron-rich foods all the time, but especially just after they've menstruated. We don't really see this happening - menstruation is more associated with sugar cravings, and that comes down to the fact that sugar makes us feel good, not that we are deficient in something. There are two exceptions to this, and they are called hunger and thirst. When your blood sugar is low, hunger signals are generated and you crave food of any/all kinds. When you're low on water, your body generates thirst signals and you crave a drink. In both cases, your body tells you what you need, but in neither case is it so specific that your body can narrow what you need down to a single nutrient. Edited to add: someone in this thread cited pica as an example of a person's body attempting to correct a nutritional deficiency. This is actually good evidence in favour of your body not knowing what to eat to address specific deficiencies, because people with pica eat non-food items. Their bodies may be saying \"there's a deficiency here\", but the physiological response to that is \"eat *anything*\", not \"eat the thing that will correct the deficiency\"."
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nt034k | How do seashells get created especially the patterns on them? | Earth Science | explainlikeimfive | {
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"It’s basically an exoskeleton created out of chitin aka carbonate calcium (you know the rock that goes fizz when you add acid to it). The animals create it themselves. And you know your fingerprints are basically how a pattern that’s random? Same thing here. The patterns you see are the growth streaks that happen as the shell grows! Yep the shells you see are 100% organic and are a result of evolution!"
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nt0nma | why does it take children so long to develop their “R” sounds? | I see kids all the time having full conversations, but they pronunce truck as twuck or brown as bwon. It doesn’t seem to be a hard sound to make, and there’s no younger rolling or throat technique involved. Are kids just dumb? | Other | explainlikeimfive | {
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"The r sound is actually quite difficult to pronounce. Rhotic sounds (r) are often the last ones for a child to learn, and it isn’t uncommon for people to never learn it and instead approximate it with a close sound, in some regions these approximations are actually more common than the original."
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nt13ex | How can air be salty? | I’ve often heard from friends that because they live close to the sea everything rusts quicker down there. Is this true? I thought if you boiled salt water you get water vapour and salt left behind. Can air be “salty”? | Earth Science | explainlikeimfive | {
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"the main source is from sea spray, tiny droplets of water that get splashed into the air and carried away like dust particles on the wind. This is why the air near the shore tastes salty too. Even smells \"salty\". Once the salt spray is in the air, any evaporation of water in the droplet will still leave the salt, and it will eventually settle out and reenter water in the next fog or rain event, leading to corrosion of whatever surface the salt landed on.",
"But to answer the second question the air can be wet, and that wetness can be from saltwater, resulting in salty air. Example: in the navy, i used to play guitar up topside. New sets of strings would be jet black from corrosion in a matter of a coupke of hours."
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nt15ql | How do very young or verbally challenged children get fitted for glasses if they are unable to verbally indicate that their vision is much clearer? | Biology | explainlikeimfive | {
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"With normal vision, an object from the world should focus to tight spot on the back of the eye, known as the retina. One way to check this is to shine a beam of light and see how big of a spot it is on the retina. Someone with bad but correctable vision would have a large spot rather than a tight one. By adjusting the properties of the beam, you can modify it so that it bends similarly to how it would go through a glasses' lens. By figuring out the necessary changes in the beam to make a tight spot, it's possible to recover the lens refractive power needed to correct their eyes! This method is more complicated and expensive than just swapping lenses and asking a if it's clearer. But it's definitely worth correcting major errors in a baby or young child's vision or else their brain will stop using the nerves from the eye, causing irreversible vision loss.",
"You know how when you go to the eye doctor, they have you look into a machine at a lighted picture of a hot air balloon (somehow it’s always the same picture), and it’s blurry at first and then it auto-adjusts to be clear? That machine automatically measures what kind of glasses you need. It works by measuring the light from the image that reflects back out of your eye, then adjusting the image until the reflected light bounces back properly in focus. Based on the adjustments it had to make, it can tell basically what prescription you need. If someone can’t sit and look in the hot air balloon machine or can’t understand the directions to do it, the doctor can do the same kinds of measurements manually, by shining a light into the patient’s eye and looking at the reflection, then trying it with different lenses until the light focuses correctly. When the eye doctor has you sit in the chair and look at an eye chart through lenses that they flip and ask you “One or two?”, they are trying to fine-tune the automatic number they already got from the hot air balloon machine. But the automatic number is already pretty good. If someone couldn’t help the doctor fine-tune any further, they could just use the automatic number. For someone who can understand speech and communicate but may not be able to read or speak, there are eye charts that use shapes instead of letters, so that the person can point to the matching shape on a card instead of reading letters out loud.",
"There is actually a relatively recent invention which allows this. It uses low intensity laser light that it shines through your eyes in order to determine the shape of the lens and how your eyes tries to naturally focus. This is far from accurate and is unable to determine many different type of vision defects but it is very quick and automatic. So you can issue prescription glasses to people who are unable to verbally speak or help with the examination in any way. Some shops are even installing these machines for use by their customers if they do not remember their prescription or think it have changed.",
"I was less than 2 years old when I got my first pair of glasses. I think dad told me they did the laser light thing. I was walking at the time. After we got my glasses, I walked into a display table (forehead height to me at the time) because I wasn’t used to seeing things with my glasses yet..."
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nt1wr8 | How a cast aids the healing process for broken bones | Physics | explainlikeimfive | {
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"Imagine trying to fix broken cup handle with superglue. When you put on superglue you have to align both ends of the handle so it perfectly fits on the parts on the cup. You have to make it fit perfectly and hold it in place for few minutes while superglue dries and hardens. Similar with our bones, doctor has to align them perfectly (or as best as possible) and then put on cast to hold them in place while bones themselves grow into eachother (like superglue but it's bone slowly growing). This all takes time and after 2-3 months bones have grown and connected and are as almost as strong as before and you can take the cast off. Depending on type of the break it might take longer and requires additional support but this is basics.",
"It allows for your limb to stay still and stiff. Giving the broken bone time to heal. They also reduce pain and swelling. The dr will put the bones together as best he can then cast the limb So they heal properly."
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nt1xl5 | Why does the left brain control the right side of the body (and vice versa)? Why isn't it more efficient to have the left control the left? | Biology | explainlikeimfive | {
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"No-one is entirely sure, but the best explanation for it I've read is that vertebrates (which evolved later) are kind of backwards compared to invertebrates--in an insect, for example, the major nerve that takes signals from the brain down to the rest of the body runs down the front of its body, whereas in vertebrates the spinal cord is always at the back. It's suggested that, during the evolutionary process that caused this switch, the nerves serving each side of the body got switched and have been that way ever since."
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nt2hif | how heart disease happens and why It's the number 1 killer In the world | Biology | explainlikeimfive | {
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"'Heart Disease' isn't a single illness/condition, it's an umbrella term for a number of conditions that affect the function of the heart. While a number of these can be congenital (born with, or genetically likely to develop it), a large number of them are largely environmental, including those brought on by poor diet, lack of exercise and other activities such as smoking."
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nt3pu1 | How does end-to-end encryption work? | Technology | explainlikeimfive | {
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"Your computer generates two numbers using fancy math: one of them is used to encrypt the message and the other one is used to decrypt it. You keep the decryption number private, but you give the encryption number to anyone who wants to send you a message. Since everyone has the encryption key, they can all make messages to send to you, but since only you have the decryption key, you're the only one who can read them. The tricky part (besides the math, which some very smart people have already figured out for the rest of us) is figuring out how to make sure that the encryption key I'm using really belongs to you. Back in the Day when end to end encryption was mostly the domain of paranoid nerds, people would meet in person to verify each other's keys. With the apps that make this easy to use, most people are relying on the app provider to tell you the right encryption key.",
"Something more ELI5: Imagine you have an envelope you want to send to a friend through the postal service, but have important things on the paper. For the info to be secured, you put the envelope in a box with a lock, and give a copy of the key to your friend. That way, you can open it at your end and no one in the middle.",
"The most common kind of encryption is known as \"symmetric encryption\". This is where two people both know the same secret number, known as a key. They can use an encryption algorithm to send messages to each other in a way that no one else can read those messages without the key. Symmetric encryption is easy and fast to compute, but has a weakness in that you have to somehow share that secret key with your partner before you can communicate with them. Thankfully, there's a fancy mathematical trick known as [Diffie-Hellman key exchange]( URL_1 ) that lets you do just that. It's a fancy math trick that can let two people, talking over a public channel, to somehow agree on a shared secret key in a way that anyone eavesdropping on the conversation can't recover the key. It's not the only way to have end-to-end encryption, but it's a perfect example of how to do it. ---- This is how Diffie-Hellman works: Let's say Alice and Bob want to create a key so they can send encrypted messages to each other. To do so, first Alice and Bob agree on a public number, *P*. This number gets transmitted publicly, so it's not a secret. Then, Alice and Bob then individually create separate secret numbers, *A* and *B*. Next, they use a particular mathematical trick to combine *A*/*B* and *P* to create new numbers *AP* and *BP*. Finally, they can then send these new numbers to each other (again, over the public internet, so eavesdroppers can see them). The math trick is hard to explain (it involves exponentiation and modular arithmetic), but essentially, it's very easy to put numbers together, but very very hard to take them apart again. You can easily take *A* and *P* to make *AP*, but turning *AP* back into *A*, even if you know *P*, is nearly impossible. Even a supercomputer would take millions or billions of years to calculate *A* from *AP* and *P*. After the exchange, Alice knows *A* and *BP*, and Bob knows *B* and *AP*. Alice of course can't get *B* from *BP* (and vice versa for Bob), but she doesn't need to. She can use the trick again to combine *A* and *BP* in the same way to create *ABP*. Likewise, Bob can combine *B* and *AP* to *also* get *ABP* (it doesn't matter what order the numbers are combined, they have the same result). Thus, Alice and Bob both now share a single secret number, *ABP*. Meanwhile, anyone who's listening on their conversation, like Eve, has only been able to copy down *P*, *AP*, and *BP*. Because there's no easy way to separate numbers using that math trick, Eve has no way to combine these numbers to create the secret number, *ABP*. She can only combine them to make, *APP*, *BPP*, or *ABPP*, all of which are useless. If that example was hard to follow, Wikipedia has a [diagram that explains the trick using paint colors]( URL_0 ) ---- Anyway, the cool thing with Diffie-Hellman is that literally no one except Alice and Bob need to know the secret number. Even the service they send messages over doesn't need to know the secret. All it needs to do is pass messages between Alice and Bob. All the secret math is done locally on Alice and Bobs' devices. That's what makes it *end-to-end* encryption -- only Alice and Bob can see the messages, anyone including the message service they use cannot."
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nt4sna | How do people sleep talk? | Biology | explainlikeimfive | {
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"When you sleep parts of the brain are meant to be disabled, one of those being the part that controls speaking. Because it's not disabled in some people, they talk in their sleep."
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nt53p7 | If the bubonic plague was present throughout so much of human history, why was the outbreak from 1346 to 1353 (the black death) so much worse than the other outbreaks? | Other | explainlikeimfive | {
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"It was able to quickly spread across all Europe (and probably north Africa too) though the Mediterranean trade network. A lack of hygiene and previous starvation also worsened the situation. Moreover, it's wasn't only the bubonic plague, there was also its pneumonic form, which is much more contagious and deadly.",
"Earlier outbreak Plague of Justinian (541-549) was pretty bad as well. There is a theory that the 1346 plague involved human fleas and lice rather than rat fleas. It could thus go more directly between people than using a rat vector. I had wondered how the rats traveled so far from the ports. There is a paper describing transmission via lice in Morrocco in WWII. [ URL_1 ]( URL_1 ) The argument against black rats is that the plague transmitted during winter, and transmitted very fast, and there are no die offs of rats described, as in other cases of rat transmission. The majority of cases described seem to be bubonic, not the pneumonic. But human louse transmission could account for this, especially if there was a variant that adapted to lice. However, it could also just be a variant bacteria that passed from human to human. [ URL_0 ]( URL_0 ) [ URL_2 ]( URL_2 ) Edit: change mistype virus to bacteria",
"Well, coronavirus have also been present throughout much of human history and infects millions of people every year. But the pandemic of 2020 have been quite unusual with a more aggressive and deadly variant. This is also the case with bubonic plague. There was a very deadly variant spreading through human populations leaving only the half of the population who became immune or who isolated themselves well enough but then the plague were mostly gone. A lot of people were immune, the deadly variants of the bubonic plague were being out-competed by the less deadly variants and people became very wary about signs of outbreaks and changed their behavior. This happened in 541 and then again in 1346 and with smaller outbreaks recorded in 1629, 1772 and 1855 onwards. The final straw for bubonic plague was that we started constantly practicing good hygiene, use good soaps, isolate ourselves from sick people, etc. which means that the bacterial infections have a very hard time spreading. Viruses are far better at spreading so we need even better techniques to deal with them including vaccines and even better hygiene.",
"Antigenic shift. Thats when the surface proteins change enough (in a drastic way) that the antibodies in circulation are incapable of binding to the new surface protein. Genetic shift and antigenic drift are two other, similar yet different, events that can explain it. But antigenic shift is the most dramatic and usually the cause of epidemics in already existent infectious diseases.",
"Primarily because of population pressures. By 1346 Europe was leaving the medieval warm age, a period in time which had resulted in warmer summers, larger harvests and a population growth as a result. As a result of population growth more marginal soils had been taken into use. Now that harvests were dropping (because of falling temperatures and degrading farmland quality) people were working harder for their harvests and getting less food. Also, the conditions for peasants were terrible (with the nobility squeezing their peasants pretty hard in most of europe). High population density of poorly fed individuals (and less able to resist disease as a result) means that europe was primed for an epidemic...and being one of the first major epidemics since CE 746 (ie, several hundred years before) meant that people weren't prepared for it in any way or form. Lots of people with the genes that meant that their immunesystem was more vulnerable to the plague (because it hadn't been selected against for 10+ generations) and society itself was unprepared. During the following plaguewaves people were much more observant to signs of disease, authorities more prepared, people were more well fed (since the thinning of the workforce had led to better conditions for the peasants) and people were the descendants of people who had survived the plague (so probably people whose genes allowed for a good immune response). So much lower R0 numbers (how many people each new sick individual is expected to infect)."
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nt5ren | Why do hangnails hurt so badly? | Biology | explainlikeimfive | {
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"There are a lot of nerve endings in the skin on your hands, so it’s likely you’ll be damaging them big time when you get a small tear in the delicate skin around your fingernail. Hopefully that’s long enough not to get binned off by the automated bot."
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nt5vyy | With the idea that aliens might be a different chemical based life form. With our understanding of Science. Is such a think even possible? | Biology | explainlikeimfive | {
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"Sure, although we have good reason to think that some of the chemistry we use is special. The easiest difference is that many of the chemicals used by life on Earth are asymmetric, and could come in one of two mirror images - but life on Earth only uses one of them. Almost all living things use glucose (a simple sugar), for example, but more properly they only use D-glucose (one of two possible forms). L-glucose is [identical]( URL_0 ) aside from being a mirror image that doesn't fit into our enzymes (in the same way that a left hand does not fit into a right glove). It's probably just random chance that we happen to use D-glucose instead of L-glucose, and so it would not be surprising if an alien life-form used L-glucose instead (and in fact, finding lifeforms using L-glucose would be strong evidence that they might not be from Earth). More generally, it's possible that other living things could be based on molecules that aren't built around carbon. Carbon has unique chemical properties that make it great for building the huge molecules necessary for life, but it's possible that other elements - particularly silicon - could do so well enough to sustain living things. But the simple answer is that we don't know whether alternative biochemistry is possible. Biochemistry, even in the simplest living things here on Earth, is unbelievably complicated and is only just starting to be understood at all. *Hypothetical* biochemistry is even harder."
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nt67ul | How do food manufacturers know how many calories are in the food? | For example, say I was a company who grew tomatoes. How would I find out how many calories are in the tomatoes? Thanks! | Chemistry | explainlikeimfive | {
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"They use Food Calorimetry, basically they burn a sample of the food and the energy released heats some water, the temperature change is a measure of the amount of calories. This tells you how many calories are in the food, it doesn't necessarily tell you how many calories you'll actually absorb from the food when you consume it (which can be impacted by variables like gut microbe composition).",
"Take the food item, and blend it into a smoothie. Dry it completely, and burn it to measure the energy output."
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nt68i1 | why do babies in the womb not get head rushes even though they are suspended upside down? | Biology | explainlikeimfive | {
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"text": [
"The head rush comes from how much pressure is exerted by gravity pulling all that blood into your head. The amount of pressure the blood exerts is proportional to the weight of the blood that’s directly over your height; which is proportional to your height. Babies are really short, so not a lot of blood directly overhead, so not a lot of pressure, so no (or very little) head rush.",
"A fetus is in a ball shape, with the legs and feet very close to the head. Thus, there is no pooling of blood in the extremities, because there are effectively no extremities."
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nt77rt | Why can't magnets bend light, considering light is an electromagnetic wave? | Physics | explainlikeimfive | {
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"Photons don't have an electric charge and thus are not affected by electro magnetic fields.",
"If you consider it as a particle, photon, it has no charge and so would not be bent. If you consider it as a wave, Linearity. Where the magnets field and the lights field would sum linearly, leaving each \"undisturbed\" by the other.",
"Light is a duality it acts like a wave and as a particle (depending on which is easier for you to work with) Light is essentially the byproduct of electrons - i.e. photons. Electrons and protons are impacted by the magnetic field of a manger because they are *charged* For example, engines and turbines and generators. Large amounts of electrons being impacted by magnets to generate large amounts of energy. Electromagnets are another great example. Photons on the other hand are *not charged* thus do not get impacted by the magnetic field of a magnet."
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nt7c0q | how do you find the root of a number without a calculator, like when you raise it to a 1/2 power, how exactly do you find the result by doing it on paper? | and similarly when you raise it to a 1/3 power or any fractional power like say, you're raising the number 4 to the 1/2 power, what process would you do to get the number 2 which is the same process you would do to get the number 3 from raising 9 to the 1/2 power | Mathematics | explainlikeimfive | {
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"[Newton’s method]( URL_0 ) It is basically trial and error, but you use the size of the error from your previous guess along with information about the slope of the function near your guess to help you make your next guess. It works quite well! The error goes down a lot with each step and you home in on an accurate answer quite quickly.",
"Lookup tables. There used to be books listing these types of numbers. If I remember correctly, calculators also use(d) lookup tables to do the same. Edit: typo",
"It depends on the number. If you try to do 4\\^½ you presumably know that the square root of 4 is 2, so its easy. Just like if I asked you \"what's 5 + 3?\" You just know it's 8, after having memorized that years ago. If I asked you \"what's 345+237\", you wouldn't know immediately, but you could figure it out using the process of addition you learned in school. There are methods for finding square roots (or any other root), but they're harder and more \"guessy\" than the method of adding numbers you know, so you don't usually learn them in school. One way is by knowing what the number you're taking the root of is close to and getting an initial estimate, then working from there. That's probably the most \"paper\" friendly way. I don't know any that don't involve some sort of guess to get started, but there may be some clever algorithm that I haven't heard of."
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nt7udv | What is a transistor and how can 16 billion of them fit into a tiny microchip? | Technology | explainlikeimfive | {
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"A transistor is basically an electronically controlled light switch. With convention home electricity, you can compete a circuit by physically bringing a piece of metal in contact with another. But then come semiconductors. Normally, silicon does not transmit an electrical signal. But, if you inject a little bit of another chemical into a spot on it... it still doesn't transmit an electrical signal. But then, if you also apply a small charge to the area, suddenly it does! This lets us create a light switch where the open/close action is not done via a piece of metal physically moving, but instead, another electrical circuit coming in to help align the \"doped\" section properly. This is a transistor. An electrically controlled electrical switch, with no moving parts. As for how we can fit so many in a small area... progressive improvements. As we build better and better machines, we can get them tighter and tighter to each other in manufacturing. There was no one sudden jump, just years of incremental improvement.",
"There are a number of types of transistors. But essentially they are electical switches. They have 3 connections, one controls the on/off and the other two are where the electrical current to flows from through and to. By connecting switches in the correct manner, you can create the basic logic building blocks (and, or and inverters) which can then be connectdd together to make more complex cells. They can be extremely small, or an individual transistor can be the size of the chip itself.",
"A transistor is a voltage controlled switch. While there are several types, I'm going to focus on MOSFET transistors as they are the ones I am most familiar with. A MOSFET has three ports: Gate, Source and Drain. Depending on the voltage applied at the gate port, a specific amount of current is allowed to flow between the source and drain ports. This means that you can create larger and more complex circuits (logic gates) by chaining the source & drain ports of a given transistor to the gate of another. How this works is a bit more complex to explain. MOSFET stands for \"metal–oxide–semiconductor field-effect transistor\", which is a mouthful. The metal-oxide-semiconductor part refers to the silicon that the transistor is made from. It's relatively easy to \"dope\" silicon to create internal crystal structures that make it easier or harder for electrons to pass through the silicon. MOSFET transfers are made of layers of these different kinds of silicon layered together really thinly. This will create regions which electrons will either want to travel through or have a hard time traveling through. If we apply an electromagnetic field to those regions, we can make it harder or easier for electron to pass through them. This is the field-effect part, and it is what allows us to control the operation of the transistor. We can still get these effect to work with amazing small layers of silicon, on the scale of single digit number of atoms, which allows us to create microchips with billions of them."
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ntaq0w | How and why do glasses work? | Biology | explainlikeimfive | {
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"You know how things look like they're an a different place when they're underwater? Like how a straight stick seems to bend when you stick it in a pond? Different materials have different densities, and light bends when it the density of the materials it's going through are different. Glass in your windows are flat and thin, so when it jogs to the side it then jogs back. But glasses are curved. Just a bit, so they change how the light goes through them. They're lenses. Your eyes have lenses too. Most folks eyes help to focus all the light into the right spots, sort of like a magnifying glass focuses the sun. But the lenses in some folks eyes aren't quite aimed right. So their glasses re-aim the light coming in to their eyes to match the bloopers in their eyes lenses."
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ntb56h | Why does our voice sound different when our nose is pinched or stuffy? | Physics | explainlikeimfive | {
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"Some sounds require air to escape our nostrils such as an mmmmm sound. When that area is impeded the sound needs to escape through your mouth making the sound strange. If you try to make a mmm sound whilst pinching your nose you will feel air accumulate in your mouth."
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ntbcyj | when did humans start studying history | Other | explainlikeimfive | {
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"Herodotus is regarded as the Father of history. Because he was the first one to properly document history. Although humans have been passing down their history in the form of stories, myths, legends and religion forever."
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ntbzgi | Why does playing audio backwards sound WAY different from someone attempting to say the same words backwards? | E.g. an audio recording of the word "farm" would sound very different from someone trying to pronounce "mraf" | Other | explainlikeimfive | {
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"Units of sound are called phonemes. & #x200B; For \"Farm\", your phonetic reading will be färm. Notice the ä sound which is like the a in \"are\" or \"arm\". & #x200B; Reading farm backwards the phonetic reading most people will use is is mraf. This \"a\" sound is more like the a in the word \"at\". & #x200B; This means that when someone reads \"mraf\" they aren't using the same sounds (phonemes) to begin with. & #x200B; On top of this, even if someone was to read it mräf with the proper ä phoneme, it would still sound wrong because when a word is played in reverse each individual phoneme in reverse too. The reversed phonemes are completely different sounds than simply reading them backwards. Someone would have to learn to pronounce each phoneme in reverse in order to properly replicate the reverse reading. & #x200B; ELI5: They sound different because they are different. Humans don't read each part of the word in reverse.",
"You say the letters backwards m r a f but the sound you make are forwards. The backwards audio also says the individual letters in reverse So em becomes me when saying the letter m",
"A human being can’t replicate exactly what it sounds like when sound waves meant to be heard forwards are heard backwards. Out of a human mouth, sound waves can only travel in one direction and phonetics have their limitations. Even if we could replicate those sounds exactly, who’s to say whether we’d have the brain power to figure out how a word sounds backwards without hearing a recording first?"
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ntc1t8 | Why is there a delay between exposure to poison ivy and the development of a rash? | Biology | explainlikeimfive | {
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"To simplify what the other guy said, the oil in the poison ivy (urushiol) doesn't actually affect your skin, and doesn't produce a histamine response, so antihistamines that you take for things like seasonal allergies won't do anything. The poison ivy actually makes an immune response in your body, like an infection would. Your body actually sends white blood cells after the urushiol, which attacks your own body, causing the rash. It takes a few days for your body to recognize the urushiol as an invader, and direct your immune system to attack. If you want to know more, the podcast called This Podcast Will Kill You did an episode on it!",
"There are basically 4 types of allergic responses, named... You guessed it, types I-IV. Poison ivy allergies are type IV, delayed type hypersensitivities. You can read more about them [here]( URL_0 ). There's a delay, relative to other responses, because there are a few steps involved. Your first-line immune cells (macrophages in the skin) take up the antigen/allergen and process it. This takes a day or so. Then they show it to specialized cells of the immune system, T cells, who call all their friends over for the allergy party. This takes another day or so. Those cells get all hopped up on cytokines and produce various enzymes and other things that cause the rash."
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ntc3ei | How does a multinational company pay it's taxes? | Economics | explainlikeimfive | {
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"Things obviously get a bit more complicated than this, but at the basic level, they usually have separate subsidiaries operating each country (though we may consider the EU a single country for this purpose). Each subsidiary then has its own separate profits that it earns in the country it operates in, and it pays taxes on those profits. It may then send post-tax profits to the parent company or some other subsidiary.",
"Gross simplification: A multinational will consist of a \"core\" company with a handful of employees located in a low-tax country, and a set of satellite companies in other countries. The satellite companies are where all of the business actually happens, but they pay the \"core\" a licensing fee to operate under their brand and access their IP that equals or exceeds what that satellite makes in income, so that it nets zero profit in that country and thus pays little or no taxes. All of the money goes to the core's profits which are taxed very little because of where it is located. There are a variety of schemes but they all revolve around one part of the multinational paying another part most of its income so it makes nothing on paper. Efforts to stop companies avoiding taxes revolve around removing or limiting exceptions for these kinds of \"expenses\" paid to other companies in the same multinational.",
"Not much different than how we pay taxes, just much more far-reaching because of how many different countries and jurisdictions they need to pay them in. For example, every Corporation that is domesticated in the US state of Delaware (as the majority are) needs to pay taxes every year by March 1st. They pay them by filing an annual report which is used to calculate how much they owe the state. If the company operates in other US states it may also have to file reports and pay them by a certain deadline. Companies will either have in-house teams that basically do this (compliance) or outsource it to a third-party like an accounting firm. That is just state taxes, they of course also owe the Federal government taxes as well. Now, multiply that by how many different countries they operate in and how many different jurisdictions they operate in and you'll see how large of an undertaking \"compliance\" items like this are.",
"They don't. Major companies will declare their global headquarters to be in a country that does not charge business taxes, then launder/funnel the profit portion of their income thru that \"global headquarters,\" resulting in no real income after expenses in countries that do tax businesses. They do pay payroll taxes, and theoretically State or local taxes, but localities and States will often give them tax deals to entice them to set up shop."
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ntc6k0 | Why do people die instantly when a bullet passes through their heart? | I just randomly thought about this, but why do people die instantly when a bullet passes through their heart if they can maintain consciousness for around 15 seconds and stay alive for about 5 minutes without oxygen? Feel free to correct me if I am wrong about anything. | Biology | explainlikeimfive | {
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"Your blood pressure essentially drops to zero and you black out. Technically there is still some brain activity going on at this point, but considering you will be unable to maintain consciousness and you will die shortly after, its fair to say its instant death.",
"a direct hit will cause near-instant unonsciousness. This has nothing to do with breathing or blood oxygentation, its the sudden drop in blood pressure to the brain because the heart no longer pumps. The brain needs contant blood flow. This is also why chest compressions are more critical can than breaths in CPR.",
"People **don't** die instantly when shot through the heart. A \"worst case\" scenario is a complete loss of blood pressure. Which means that you become unconscious within 3-10 seconds. If the bullet doesn't shred the heart or the aorta (and instead nicks a heart artery) the effect isn't nearly as fast and it will take several minutes (or even several hours). Then it takes another 5-ish minutes for the cells most vulnerable to oxygen deprivation to die (your braincells. Other organs, such as muscles, can survive far longer). This is because there is a pretty big difference between the level of energy needed for cells to perform work (like thinking) versus just maintaining cell function. If bloodpressure with oxygen rich blood is restored within that limit there is a chance to revive the victim (not likely if the aorta or heartchambers have been shredded). P.S: The only case where people \"die instantly\" is when there is extensive damage to the brain or brainstem. The cells (well, the ones that haven't been ripped apart) will live on for a few more minutes, but the ability to maintain \"you\" is gone pretty much instantly.",
"Another thing to consider is what part of its cycle the heart is in when a bullet slams into it. If it's gets hit the moment it's pumping then it can cause a massive spike in blood pressure throughout the body which bursts blood vessels in important places, like the brain, and causes immediate brain trauma. (Read this in a hunting magazine years ago when they figured out why big game sometimes dropped suddenly when shot through the heart, and sometimes didn't. I'm assuming the same thing could happen in humans.)",
"What exactly happens when your heart gets punctured by a bullet: 1.) When the heart gets punctured by the bullet, the blood starts flowing out into the mediastinum (the space in thorax where the heart and lungs are). This blood soaks the lungs and the lungs collapse, making breathing far more difficult. Think of it as a big hemorrhage in your thorax, where the thorax gets filled with blood from within. 2.) Because of the hole made in the heart by the bullet, the blood instead of circulating normally through its physiologic pathway, gets diverted. This leads to a sudden drop in blood pressure. This drop is blood pressure is low enough to trigger a syncope (loss of consciousness) which eventually leads to death in a matter of a few seconds. 3.) Because the BP has dropped, the blood isn't really moving much. This triggers the coagulation which leads to the formation of thrombi (blood clots) within several vessels which further accelerate the processes such as, getting a stroke and organ failure. To sum it up, it might take a few seconds to a few minutes for the person to die. This entirely depends on how big the wound/damage is. If the bullet used is really small and is travelling at a relatively slower velocity (bb gun fired from a distance), it will nick the heart but won't cause as much damage as an AK would, when fired from the same range.",
"You don't. A bullet through the heart for our purpose here is known as a cardiac tamponade. Two things happen at the same time and rather quickly. First the exiting blood decreased your blood volume. Your body tries to compensate this lowering blood pressure by beating increasingly quicker. A formula all nurses and Dr's know is circulating volume = stroke volume X rate. This is critical for maintaining tissue perfusion. Stroke volume is the amount of blood ejected each time the heart (left vertical) contracts. If the stroke volume decreases as is the case in hypovoleama (like a hole in the heart) the heart beats quicker to compensate. It will continue to beat increasingly quicker until the heart can't go though it's whole beating cycle (PQRST), and it starts of overlap. This is ventricular tachycardia (VT). AKA cardiac arrest. At the same time, the cavity that the heart sits in is filling up with blood and squashing the heart, making is increasingly harder for it to contract and relax. Eventually, squishing will also cause the heart to go into VT (we see this with 'collapsed' lungs sometimes). So you can see that you don't actually die instantly, rather you go into cardiac arrest and die rather quickly.",
"They don't die instantly. They likely freaked out for a few seconds before going unconscious and dying after a few minutes. They just say that the person \"Died Instantly\" to make the family of the victum feel better about what happened because \"Atleast they didn't feel any pain.\" For example. If you were the father of a young man who got hit by a drunk driver. Would you want to hear that their last 20 seconds on earth were spent laying on the ground trying to breathe but they cannot?"
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ntc8bv | How do spam callers mask their phone numbers to ones registered to someone else? | Technology | explainlikeimfive | {
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"When you get a phone call and a number shows up on your caller ID, that's not always because your phone knows which number is calling it. The phone that's calling you can send the call *and* tell your phone what number to show, plus maybe a name as well. Scammers use a VoIP phone and can just alter the data that their phone sends to your phone, your phone doesn't know any better and just shows what ever the other phone tells it to show. Edited for clarity.",
"It's called spoofing, and it actually exists for legitimate reasons. For example, a business with many individual phone lines may want them all to show up the same on caller ID so that customers call the correct number back. Or a person may want calls from their cell phone to appear to come from their office phone. Unfortunately now we're dealing with people misusing this system. It used to be somewhat complicated to spoof a phone number but these days it's trivially easy. That's because a lot of phone traffic isn't actually done over traditional phone networks, it's done over the internet using a protocol called voice over IP (VoIP), in which case all you have to do is send deliberately incorrect caller ID data.",
"The telephone backbone operators such as AT & T have no incentive to block spam calls. They profit from it. Perhaps it even makes up the bulk of their call traffic. So although they could shut down the spam, they will be making excuses until they are forced to somehow. The reality is, despite the fact that the presentation caller ID may be spoofed, the billing number cannot be spoofed. The VoIP call traffic is well known as it enters the telephone network and they turn a blind eye to it.",
"Phone guy here. Depending on the carrier, I can send whatever the hell I want over as the caller ID. I can legit send 123 to your phone. Now you have to sign all sorts of legal docs saying you won't do anything untoward... But when has that ever stopped anyone. It's just a field in the PBX (phone system) and we can put whatever we want in there. It's normally used to send the main number of the facility or department, but nothing stops me from sending complete bogus junk. Also, VoIP has nothing to do with it. It may make cheating easier, but I can send absolute trash over a standard PRI (old fashioned telephone service on a T1) with the right settings.",
"Spoofing is when you are pretending to be a directory number that does not belong to you and masking is when you want outbound calls to appear from a different directory number of your org. Masking is done for a number of legitimate reasons. Most carriers will check and enforce the format of the directory number but do not check if that number is yours. If carriers enforced not accepting directory numbers onto their network that don't belong to the peering org we could eliminate a lot of spam and spoofing. They have the network resources to do this but it would add some overhead and cost and would require laws and regulations which isn't easy.",
"They use software on their own phone station (PBX, which they connect to other phone systems' network) to spoof the caller ID. There are often little to no checks on Caller ID validity in systems that control the whole thing. It is enough for the spammers to be a trunked client of a phone company (e.g. via a PRI or a SIP trunk) to get enough access for this. Many completely normal businesses subscribe to such service, there is nothing unusual in having a PBX to route calls in your enterprise office.",
"It's called caller ID spoofing. Like several others have said, the extremely boiled down version of it is you can use software to mimic whatever number they want. You know those calls you may get what there's no one on the line? Scammers typically send out probing calls to determine if the number is active or not. If the number is in your area code and exchange (first six numbers) then it's either a probe, or if you answer and someone with an Indian accent starts talking about a \"suspended social security number\" or some such other nonsense, just hang up. Also, if you subscribe to a voip service, please PLEASE create secure passwords for your account and log in often. I work as tech support for an ISP/voip provider.",
"When a phone call is setup over a digital connection, the originating call system has the ability to set the outbound calling information, name and number along with some other information, which is transmitted along with the call setup data. This data could be overridden by the phone carrier but is typically allowed to pass. In a legitimate scenario, this is how you know to call back an individual versus a main number in a local business. In nefarious scenarios this information is either blanked out, completely random, or chosen to be something likely to be more acceptable to the called party such as a local number. By happenstance that number at times is someone you already have in your contacts, but many times not. A truly crafty organization could use leaked call records to ensure that they only present the call as coming from a number you have called by searching in leaked call record data."
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ntcnco | Why must I add milk, butter, or alcohol to cannabis tea? | Won’t it work without these additives? | Other | explainlikeimfive | {
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"THC is a lipid and has poor water solubility. It has much better solubility in fats and alchohol. In other words if you just made a tea with water very very little THC will end up in the tea."
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ntcotd | What causes line-dried clothing to get stiff when dry, compared to machine dried clothes? | I've noticed that clothing that's laid flat to dry or line dried usually feels stiff, while clothes dried in a dryer don't feel this way. What's different about the two processes to cause this? | Physics | explainlikeimfive | {
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"Soap and salt/mineral residues will dry on your clothes either way. If they are tumbling in a dryer, this breaks up the residue and leaves the clothes feeling more flexible.",
"Well one big impact is likely that one is in a single position, the other is going round and round."
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ntde58 | If rice is the most water intensive crop, why do countries continue to grow it? | Don't get me wrong I love rice, but if so many countries are struggling with water shortages, wouldn't it be better for the world if we stopped growing rice? | Earth Science | explainlikeimfive | {
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"Generally, the areas of the world that grow rice have plenty of water, either from large rivers or from plentiful rain. They can’t really ship that water to places that need it. Reducing water usage in China isn’t going to bring rain to California or the Sahara.",
"The countries growing rice are really not growing them in the same places with water shortages. Like just because there's a water shortage in Nevada doesn't mean there's one in South Carolina. Rice also is a great staple hood. We have enough hunger in the world that not growing rice would leave more people hungry.",
"Rice is grown in places where there are no water shortages, and we can't exactly fix water shortages by shipping water either since water is too heavy and hard to manage for it.",
"Weirdly, rice doesnt even need to be grown in water. It'll grow just fine on dry land. It it a 'water tolerant' crop the same way as kalo. They grow it in water because they have plenty and weeds can't grow in the water, so it's easier to tend.",
"Rice *is* a water intensive crop, but it's not *the* most intensive crop there is. Other crops, such as cotton or bananas, need way more water than paddy rice by growing period, with *the* most water intensive crop actually being sugarcane. Then, you need to understand where rice came from. The centre of origin of rice is Asia, and it was first domesticated in the Yangtze Valley in China, which aside from the right climate and soil conditions, had a lot of water available. It is *natural* for rice to be grown there. 92% of the world's rice is grown in Asia, where water availability isn't as limited as in other countries. Sure, growing paddy rice in California doesn't sound like the best idea, but doing it in Japan makes a lot of sense. Also, rice is a staple food, and primary source of carbohydrates for many countries and over 50% of the population, while also being a key cultural element. Not all rice is grown in s paddy, though. Many places where rice is not native use a semi-drt or dry regime, though that implies an increase in the use of herbicides and pesticides... Fun fact: Mother nature, ever so wise, created one source of carbohydrates and proteins for each civilisation development area, adapted to their climate conditions. The Americas had corn and beans, the middle east had wheat and lentils, and Asia had rice and soy."
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nte6yr | How did minimalism dominate UI design and architecture? | Other | explainlikeimfive | {
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"It's one of the basic tenements of design. Simplify. No superfluous details. Function before fashion. Technology accentuates this because of the need to be easily learnable."
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nte7rn | Why are twins more likely the older a woman is when pregnant? | I was reading about the risks of pregnancy in women above the age of 35. One of those is the increased chance of twins. Is this because the older a woman is, the more likely it is that they have had IVF, or is there also a natural biological reason that twins are more likely to occur? Is the increased chance based on all pregnancies, whether natural conception or IVF, or do they factor in IVF vs natural conception when discussing the increased chances? | Biology | explainlikeimfive | {
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"I think Dr Sapperstein said it best: \"It's not uncommon for 2 or more eggs to be released at once when a woman is older. We call it, and I mean no disrespect, a going out of business sale.\"",
"It’s an increased chance based on natural pregnancies, not including IVF. The reason is that as you approach menopause, the ovaries don’t work as well, and they kind of start sputtering and working well some months, and poorly the next, like a car that is having engine trouble. When the ovaries aren’t working as well, they stop producing as much estrogen as they used to. So there’s a complex relationship in the endocrine system between the pituitary gland and the ovaries, where the pituitary sends a hormone message to the ovaries to get an egg ready for ovulation. And the ovaries send a hormone message to the pituitary letting it know it is getting the egg ready. But if the ovaries are not working so well and not getting an egg ready, the pituitary sends a louder message to the ovaries, which can cause the ovaries to be overstimulated and make extra eggs. The pituitary hormone that does this is FSH, and it’s the same hormone that they use in fertility treatments to cause twins and such. tl;dr: as you get older, the body naturally makes more of the same hormone used in IVF to cause multiple eggs to be ovulated."
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ntflfh | how does the human body transform ATP into movement, heat and energy for the brain? | Biology | explainlikeimfive | {
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"Every chemical bond within a compound consists of energy. ATP is incredibly useful because breaking the phosphate-phosphate bond provides a good amount of energy. So in short, breaking this particular bond in ATP gives energy for our cells to carry out reactions and other processes that need an energy-input to occur."
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nti0ut | If you caught all the steam from a kettle in a container, would it weigh as much as the water that was originally boiled? | Chemistry | explainlikeimfive | {
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"Yes. This is Le Chatelier's law. Matter can't be created or destroyed so any chemical reaction doesn't change the mass. (The mass could actually be a little different due to impurities in the water that were left behind) Edit:mass not weight"
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ntitlk | Can iron be a gas if it's very heated? | Iron can be a liquid on very hot temperature, I'm wondering if iron is heated so hot that it turns into gas? Is it possible? | Chemistry | explainlikeimfive | {
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"Technically speaking yes, at 2,862C it would start to boil, but it would be highly reactive and wouldn't be \"just\" iron anymore. I imagine boiling it in a vacuum would achieve Iron gas. Edit: 2,862C is about half the temperature of the surface of the Sun",
"Maybe in an environment without oxygen. Iron will burn long before it will turn in to a gas. Look up combustible iron dust.",
"There's a huge meteor crater in Arizona that was produced by a meteor that contained a lot of iron, and the impact vaporized a lot of the iron. The iron vapor condensed into droplets that scattered all over the place like buckshot. People dragged magnets around the desert to collect these things, and I saw a jar full of them at the visitor center when I visited the crater, years ago. So, yeah - iron can be heated into a gas. It takes a LOT of energy, but it's possible."
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ntjkse | How can the ear distinguish the different instruments from a song after all the layers have all been mixed into one track? | Biology | explainlikeimfive | {
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"All instruments (and noises in general) have a distinct tonality and register that our brains are able to recognise and differentiate between, which is why you can pick out individual layers from a single recording"
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ntkhag | How prehistorical people dealt with their nails and hairs ? Even tho there were no fashion style back then, i assume it would get difficult to hunt and all with very long nails and hairs | Other | explainlikeimfive | {
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"Nails do get worn down when you use them. Even today not everyone needs to clip their nails as they use their hands enough to wear them down. We do not know very much about hairs though as most hair grooming tools would have rotted away before we could find it. But we do have some prehistoric combs which indicates people were taking care of their hair. And a lot of the stone knifes we find is sharp enough to cut hair. So it is very unlikely that people had long unkempt hair. But we do not know much about the hair styles which were popular for hunter gatherers.",
"It's very easy to assume prehistoric equals primitive. Aiui that's a risky assumption . I imagine people had the same desire to look good in some particular way as many of us do today. Flint tools can be very very sharp, haircuts and shaving would have been possible. We know from cave paintings that pigments were used , so some sort of makeup could have been possible too.",
"> How prehistorical people dealt with their nails and hairs ? Even tho there were no fashion style back then, i assume it would get difficult to hunt and all with very long nails and hairs While I can't make any claims on presence or absence of prehistoric fashion, hair is fairly trivial to trim with any sharp edge. Just grab a sharp stone and try it. Nails are naturally worn down by regular physical labor."
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ntkkgq | how reflecting light (by reflective objects) and the concept of colors differ | so if an object is white colored, that means it didn’t absorb any color from white light and reflected all the colors so you see white color. how does this concept differ from when you reflect light with a mirror for example? why do you see ‘reflected light’ rather than have the mirror seem white in color even though in both cases light as a whole was reflected? i’m pretty sure i’m misunderstanding something here about the concept so can someone help explain it to me | Physics | explainlikeimfive | {
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"A white object reflects all colors equally in all directions at once. A mirror reflects all colors equally in a single direction, at an angle equal to the angle the light hit it at. This is why when you look in a mirror you see a specific point that had its light reflected, while when looking at paper you just see a generally lit up surface."
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ntkytr | Why do some shower handles have that dramatic change in temperature when you turn it very slightly? | Other | explainlikeimfive | {
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"text": [
"A combination of humans being very sensitive to temperature, water being a good thermal conductor, the miscibility of different temperatures of water, and the mechanism of your tap. You'll feel a small change in temperature of your shower water more keenly because water conducts heat better than say air, and humans are very good at feeling hot things as very hot and cool things as very cold. Plus, hot and cold water don't mix as well as cold and cold water, so some mixer taps don't actually mix the water very well, plus water travelling through a pressure-balancing tap will be affected by the pressure of the water coming in through the other channel; a bias towards hot or cold will be exaggerated by the other channel being resisted."
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ntl4gj | How do your lungs filter out dust in the air? | I was cleaning out an A.C. Units air filter and it got me thinking. We breath in the same air so how do we clean out our filter? | Biology | explainlikeimfive | {
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"Naturally, the hair in your nose doesn’t get everything. Big things, like grit or dirt will get caught in your mouth or throat, finer particles will get stuck in membranes further in your lungs and coughed back up as mucus. We catch and spit up most. When it comes to work, If you can see it in the air, you are breathing it and need a mask. If it’s a manufactured material, it likely contains toxins you won’t cough up.",
"Mucus. Think about how a smoker expels all that tar they inhale. They gob it up in huge gross coughing fit complete with black loogie. Yep. And just like the smoker the process is not 100% accurate. There's lots of bits left inside the lungs to accumulate and make breathing more difficult. Same thing with any fine particulate matter. Wood dust. Chalk. Asbestos."
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ntlpwe | Does a hard drive change its weight if it's full storage? | Technology | explainlikeimfive | {
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"No, it doesn't. Data is stored as electrical charge, either on the platters of the drive, or within the solid state memory chips on an SSD. Adding electrons to or removing them from sections of the storage does not alter the weight. Additionally, the \"empty space\" on a hard drive isn't just a bunch of zeros. It generally has either old deleted data, or random data. What gives each sector of the platter meaning is the record of what files are located in what locations on the drive. So, the actual difference between a full and empty drive is a little bit of the structure of that index.",
"An \"empty\" hard drive isn't physically empty, it's just full of random meaningless data. In the beginning of the hard drive there's a table that says what files are on the drive, where they are physically located, and which parts of the drive are currently vacant. The vacant spaces are just filled with random 0s and 1s.",
"Wait wait wait... Magnetic drive or solid state?",
"No. A hdd is sort of like a collection of light switches. The data is stored by leaving each switch up or down. The switch doesn't change weight depending on which way its flipped."
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ntlrfh | () What are antibiotics made of? | I know narcotics are made from poppy plants or opiates or whatever but what is the “active ingredient” in an antibiotic pill? How are they made? Thanks! | Chemistry | explainlikeimfive | {
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"As with \"narcotics\", there are usually many different classes of chemicals that can be used for a similar medical application. Each with a distinct structure and thus way of manufacturing. Some antibiotics are derived from naturally occurring substances, e.g. penicillin which is produced by a fungus. These are usually biologically made from peptides (small proteins), often with sugars attached. Other classes are purely synthetic and are made by chemical reactions in a factory."
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ntmh7k | How do genetic variations work? Why are chimpanzees and apes remarkably different than us although we do share 95-99% DNA? | Biology | explainlikeimfive | {
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"What most people don't realize is how much of the genetic code is required just for the most basic functions of life. It's like using libraries when writing an app - you can make very different apps just by shuffling around what you use from which library, while adding minimal code yourself. Think stuff like making proteins, reading and copying DNA, reacting to the availability or absence of food, scheduling cells for division,.... All of that takes *a lot* of code and is basically the same everywhere.",
"Think of two Windows computers, one running a video game, the other running a spreadsheet. 95% of **all** the code running on both those computer is identical. They share the gigabytes of Windows code that is required to keep the programs running. They both draw windows and widgets the same. They both read the mouse and keyboard the same. It's like a pyramid where the top bit is what makes an animal one kind or another, but they share a lot of foundational things. All life needs the bottom most part. Mammals shared even more. Primates have even more things in common. They we get to our most recent living cousin species and it turns out we share a lot. That 5% that's not the same is what makes each species what it is.",
"You got eyes, a chip has eyes, you got a butt, it has a butt, you got lungs, it has lungs. The variation is very small compared to how much of the basics are the same.",
"From the reading I've done on it, dna code is incredibly complex. Say you're reading a book and one letter or space is out of order, instead of being a minor typo, it changes the entire definition of a paragraph 5 pages earlier. So a 1% difference in a code that is millions* of characters long is a pretty big difference. If you want a some what simplified but thorough analysis check out \"A brief history of everyone who ever lived\" by Adam rutherford. * don't quote me on that number, but its a big number.",
"“remarkably different” is a stretch. chimps are essentially out little brothers in the animal kingdom. within that ~2% are very minor differences. things like olfactory receptors; they have more hair than we do; we stand upright which comes with a number of skeletal changes, especially in the pelvis. intelligence wise, we have the same exact nervous system as a chimpanzee, just 3x as many neurons, which comes from our prenatal brain development."
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ntms2s | Why are places like Amsterdam, Baku, Dead sea or the badwater basin dry places despite being below the sealevel. What stops the sea to flood these areas? | Earth Science | explainlikeimfive | {
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"In the Netherlands its the dunes basically. Sand washed up by the sea that has created sandy hills that are higher than sealevel and the land behind it. Also dikes.",
"They're low elevation surrounded by high elevation. Like pushing a bucket down into a tub of water. As long as the lip of the bucket remains above the water then the bottom stays dry. In the case of Amsterdam, the \"lip\" of that bucket is in large part man made. With pumps to continuously pump out the water that flows inland from the sea."
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ntn62q | Why do schools have a no-tolerance policy for hitting back? | Other | explainlikeimfive | {
"a_id": [
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"text": [
"I’m a school principal and my school does NOT have a zero tolerance policy. This is why some schools do. Almost every child and their parents claim that *they* are the victim in a fight. Even when you *see* it happen or there’s CCTV and all the evidence is a slam dunk, the antagonist and parents will almost always say that the victim deserved to be hit, kicked, spat on, etc... because of something that happened off camera or earlier in the day or because the victim had been ‘bullying them for years’ and they had finally snapped. Schools are non profit making organisations, often run on a shoestring. They do not have the time and resources to provide staff to investigate every single incident and claim. Therefore, some schools opt for ‘zero tolerance’."
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ntn8ud | how does companies like Apple says ,,this product is non-repairable” but you can still repair it? | Technology | explainlikeimfive | {
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"text": [
"There’s a big battle going on over ‘right to repair’ right now URL_0",
"Because they want you to pay three times as much for their licensed repair people instead of attempting to do it yourself. If you can do it yourself they don’t get more money out of you. Some companies also have proprietary parts, for example, Nintendo has proprietary screws that you need to buy a specialised screwdriver for, to discourage people from attempting to repair things themselves."
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"https://www.bloomberg.com/news/articles/2021-05-20/microsoft-and-apple-wage-war-on-gadget-right-to-repair-laws"
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ntnefi | How can there be lactose free milk? | Chemistry | explainlikeimfive | {
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"text": [
"Lactose intolerant people are unable to produce an enzyme called lactase that breaks down lactose. Without the enzyme, the undigested lactose causes digestion problems. Producers can simply add lactase enzyme to the milk before selling it, making sure the lactose is pre-digested before someone drinks it. A common alternative comes in the form of lactase tablets people can take whenever they can't avoid regular dairy products."
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ntnlxq | Chemically, what's the difference between "nebulizing", "diffusing", "atomising", "aerosolizing", "aromatizing", "vaporizing", and just spraying? | Chemistry | explainlikeimfive | {
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"text": [
"Hopefully someone will give you a fuller explanation, but at least for some of these the difference is droplet size. So, for example, droplet transmission vs aerosolised virus. Droplets are generally bigger than 5 microns in size, where a micron is a millionth of a meter (a.k.a. a micrometer), or at least 0.000005m. Aerosolised particles are much smaller than this. This also means they can hang in the air for longer, and potentially travel further, than droplets. Droplets will fall to the ground pretty quickly, like within seconds. But aerosols can hang about for hours, and could end up in ventilation systems etc. So whether a virus can be carried by droplets or by aerosols can make a *huge* difference in how to handle it."
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ntnzwo | - Why do some houses get hard water and others don't from the same source? | Given roughly the same age, type of plumbing, and being less than a mile away on the same municipal water source, how do some houses get effected while others dont? | Chemistry | explainlikeimfive | {
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"If all those facts are true, then perhaps one of the homes has a water softener system that treats all water as it comes into the house. Probably located near the water heater in the basement, utility room.",
"If they have the same water source and no treatments, they will both have the same water. But it’s definitely possible for houses a mile away to have different sources. Either from different underground municipal systems, or different wells. Or one of them is softening their water",
"In my city, while it’s one municipal water department, the water delivered to one house can be very different from water delivered to another house a mile away. We have multiple sources of water, and multiple blending stations. One end of town, it’s all groundwater; on the other end of town it’s mostly river and lake water. In the middle of town it’s a combination."
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ntosln | What is bankruptcy? | How does it work? What kind of debt does it work for? Who can do it? | Economics | explainlikeimfive | {
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"Bankruptcy occurs when a person or entity (e.g. a corporation) has debts that exceed the ability to pay. It is a legal process (not an event) that involves debt restructuring and consolidation, negotiation with creditors, and, if necessary, liquidation of assets to repay debt. Personal bankruptcies, depending on the jurisdiction, result in a person having to rebuild their credit rating over a certain number of years before being eligible for credit again. Corporate bankruptcies can result in the dissolution, break up, or outright sale of the corporate entity, or it can result in a new, restructured entity with different leadership. There's much more to it than this, of course, so if someone wants to fill in my gaps, please do.",
"Bankruptcy is a formal court managed process to manage a situation where an individual or company does not have sufficient cash or current assets to pay their current liabilities. There are many kinds of bankruptcy. Personal and corporate are very different and even within each type there are different forms of it. It works on most debt - but there are exceptions (for individuals, I believe federal student load debt is not dischargeable through bankruptcy). Well bankruptcy is a self-declaration. Technically anyone or any company can do it. But it is cumbersome and has long term negative ramifications. There are too many details involved and generally speaking (not advice!) unless significant assets and liabilities are in play, personal bankruptcy should be a \"final\" option after trying to negotiate outside of the court mandate. It is VERY tedious since it involves the court - so it isn't simply filling out a form and sending out some letters. There will be a lot of documentation. Completeness and accuracy is important - be aware the deliberately misleading or lying to the court is a crime (ie saying that you have no money by sending your cash to a friend or relative is not an option!).",
"Personal bankruptcy is a legal process that people can use to protect themselves when they accumulate an insurmountable amount of debt without a reasonable ability to pay it off. The court helps them restructure their debt, consolidate loans, negotiate with creditors, and liquidate assets to help them pay down the loans. Certain types of unsecured debt are erased or reduced, while others have to be paid down. Student loans in the US for example are notorious as they cannot be erased, while credit card debt and lines of credit can be forgiven. The price you pay for bankruptcy (in additional to the legal fees) is the destruction of your credit rating. It will take years for you to build a credit rating back up to be able to borrow money again. So while bankruptcy may seem like an easy way out of massive debt, it has long term implications to your life and should only be considered as a last resort. It's also quite possible that you will have to offload assets. Cars, extra equity in your home, etc could be liquidated to help pay off creditors. It's important to note that while a lot of people go bankrupt due to poor financial choices or financial incompetence, there's also a lot of people that are forced into bankruptcy through no fault of their own such as losing a job or a failing business, or unexpected medical expenses. Bankruptcy can also help you in the case of being slapped with massive court fines, for example most of the people who were fined for downloading music in the early 00's on Napster declared bankruptcy rather than pay the ridiculous fines imposed on them by the courts and record industry."
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ntp7mh | What are the biological reasons why exercise doesn't immediately have an effect on your mass? | Biology | explainlikeimfive | {
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"text": [
"Exercise does have an immediate effect on your mass. It is just not a lot per hour. Your metabolize will be higher when you exercise. So you will convert the sugar/fat/proteins with the oxygen you breathe to carbon dioxide and water. You will breathe out the carbon dioxide and the result is a reduction in mass. If you sweat you lose water and your mass is reduced. This is if you do not add anything, if you drink a lot of water the result can be a temporary net increase in mass. The effect in not necessarily easy to notice because a normal individual might be able to use half a gram of fat per minute so 30 grams per hour. This is less than a mouthful of water, I did a test with a kitchen scale and for me, a mouthful is 70 grams. The result is that you need many days of exercise to see a change that is more than daily fluctuation from water and food intake. So the mass is lost directly the problem is that it is not a lot. So it is likely that you dink water so and the result is a temporary increase in mass."
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ntpgcf | What goes on in brains that affects concentration when drowsiness sets in? | Biology | explainlikeimfive | {
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"text": [
"Your body produces certain hormones that send the message to cause that sensation. For instance, just before bed your body produces melatonin, which causes drowsiness and makes you fall asleep easier."
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ntpvln | How can someone understand whether a piece of metal is pure gold or not? | Chemistry | explainlikeimfive | {
"a_id": [
"h0t7iju"
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"text": [
"Gold has a known mass. If you can measure the volume of the piece, you can find what it should weigh if it is pure gold. You then weigh it and compare the two values. That's the simplest way, readily available to just about anyone on the planet with a scale and a container of water."
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ntqee8 | How can modern scales not just tell me my weight, but also how much of that weight is water, muscle, fat etc. | Technology | explainlikeimfive | {
"a_id": [
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"text": [
"They use electrical current. It's called bioelectrical impedance analysis (BIA). When you stand on the metal contacts on the scale, a small electrical current passes through your body. Different types of tissue offer different levels of resistance to that current. That said, BIA scales are notoriously inaccurate. Even the best scales can be off by quite a large margin, particularly due to the way the numbers can be greatly skewed by things like your hydration level."
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ntrr9s | how do planes fly under the radar? | Physics | explainlikeimfive | {
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"text": [
"Radar needs a clear line of sight to the plane in order to be able to detect it. If the plane flies low enough, that line of sight is broken or obscured by hills, buildings, horizon etc.",
"Conventional ground-based radars get confused by all the clutter near the ground (building, hills, etc.). As a result, they can’t reliably see objects in a band of low altitude against the ground. If you can fly there, the radar generally can’t see you. You’re literally flying under the (effective) detection zone of the radar. The challenge is that now you’re flying really close to the ground…this takes special training, routing, and potentially special aircraft controls depending on what you’re doing.",
"A radar works by sending out a radio signal from its transmitter and then seeing if that radio signal gets bounced off something like an aircraft and gets returned. However radio signal can con go though the ground. The radars therefore tends to be mounted on top of high hills or mountains so they can see further but aircraft may still fly low enough so there is always some ground between them and the radar. Even without the help of hills to hide behind they may hide behind the curvature of the Earth."
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nts65v | how chemical castration works. | Biology | explainlikeimfive | {
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"text": [
"The usual drug used is called Lupron. It’s something you would have to take on an ongoing basis. It works by telling the pituitary gland to produce less testosterone. A doctor would have to prescribe it. Keep in mind that the purpose is to reduce the sex drive to the allow the patient to more effectively deal with their issues via therapy. You will most likely have to be in serious therapy while you are taking the drug. Certain people are on it long term.",
"Chemical castration reduces sex drive and usually the ability to obtain or maintain an erection. It doesn't sterilize you, it just makes you uninterested in sex and unable to perform. It's one of the major side effects of antidepressants. Whether or not your doctor will prescribe such a thing depends on your doctor and your unique case. Talk to him about it, no one else can say with any certainty if you can obtain such a thing.",
"I would say that a therapist would help you be able to get one, as they do for people who are only attracted to children. It helps those individuals stop those feelings and not end up hurting children or facing jail time for those things. I don't know if this is your reason or not. But seeing how those people were able to receive that might give you an avenue. Just my thought when I read your post."
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ntt6oi | Why aren't phones like laptops when installing operating systems ? | I mean you can get any random laptop install windows or linux on it and it just works but for phones you have to get custom roms specific for your phone. Aren't phones essentially same as computers ? | Technology | explainlikeimfive | {
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"Technically this utopia is totally possible. This problem is basically a manufactured one. Apple won't let you do anything cos it wants the absolute control over your devices and the OS on them. Within android things are a little more open, you might be able to install some other flavor of android if you could get your phone's bootloader unlocked, but you'll have to jump through hoops. Basically everyone wants to lock you in, to some extent.",
"Yes and No Phones require a purpose built and stripped down operating system to work on their hardware, so you can't install PC windows on them for example. But why aren't phone OS's universal like on PC? Because the phone manufacturers *want* it that way. They've deliberately engineered the market so that you have to get both the hardware and OS from the OEM. Everything is proprietary. Android is an open source platform but manufacturers still tweak it to make it proprietary for their devices (ie drivers and plugins). They've created an ecosystem where they control the hardware and the OS exclusively, and have a stranglehold on the peripheral market. They also create devices with built-in obsolescence ensure that people will have to but new phones every couple of years. Even simple things like batteries are functionally not replaceable in modern smartphones which seems like a massive over-site but is in fact a deliberate act to encourage people buy entirely new phones instead of repairing older ones. Eventually a 'universal smartphone' will be developed, but the big manufacturers have zero interest in letting this happen. In the short term this will only happen with regulatory (ie government) interference. Left to their own graces the PC industry would have done exactly the same thing, but a critical mistake made by IBM in the late 70's led to 'universal computer' that we take for granted today. IBM at the time saw no future for a Personal Computer so they didn't bother to design one. That was until Apple released the Apple II. In a desperate attempt to get to the market IBM built the first PC using off the shelf parts, and used a pre-written OS (DOS) written by one of it's partners Microsoft. Because most of the parts were widely available, and IBM foolishly hadn't secured an exclusive contract with Microsoft for the OS, other manufacturers like Compaq and Dell were able to reverse engineer the PC and flood the market with Clones at half the unit cost. Other computer platforms like Amiga and Commodore also existed at the time, but the universal PC won out in the long run exactly because it was a universal platform. Purpose built machines with restrictive hardware and software licensing became doomed to be niche product (like Mac's today) Today ALL PCs are clones, there are no original IBM machines left."
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ntth8m | If light (photon) has no mass, how is it affected or bent by gravity? | Physics | explainlikeimfive | {
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"Gravity bends space-time and as light follows it's straight path it follows the bends. So what would appear as something bending light is in fact something bending space-time and light just following that.",
"Photon has energy, and Einstein’s famous formula E = mc2, postulates that energy and mass are equivalent. So gravity affects light because gravity actually affects mass-energy, not just mass."
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nttzrx | What factors of the rainforest made such a wide range of species appear? | I’m aware why there is such a high amount of animals in the rainforest, because the high vegetation means more animals can be supported. But what factor of the rainforest led to such a wide range of species, as oppose to those in other regions. | Biology | explainlikeimfive | {
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"One of the big reasons for the high level of diversity in the rainforest is the abundance of energy. The sun provides lots of energy for plants to grow because in remains intense and steady all year round. Paired with abundant water that means lots of plants growing very quickly, providing energy to all the things that eat plants. When the base of the food chain is so rich, that means you can fit more trophic levels into the chain (more things which eat other things). On top of that, just like with governments, huge budgets mean that even relatively small ecological niches have plenty of energy to survive. Compare the rainforest to a dessert, or the arctic: while there will still be plenty of biodiversity if you look for it in an energy poor environment, it will significantly less than in the energy glutted rainforest. Essentially, there are so many species because there is energy to spend to support them all! Life will expand to fill in every nook and cranny available, and change to fit those niches more efficiently."
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ntu3sb | . Why are chimps so much stronger than humans for their size? | Biology | explainlikeimfive | {
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"They aren't it is a misconception, their arms are stronger due to moving through trees but their overall strength isn't great. Edit - URL_0",
"It's about tendon placement. If your biceps and brachialis (elbow benders) were connected slightly further down your forearm, you'd have more leverage with the same amount of force applied by your muscles.",
"The greater strength of chimpanzees, relative to humans, may have been explained by American scientists. A study suggests the difference is mostly due to a higher proportion in chimps of a muscle fibre type involved in powerful, rapid movements."
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ntuqkt | () How is space uniform in temperature? | Physics | explainlikeimfive | {
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"Space is almost entirely empty. There's nothing in it. That means there's nothing in it to have a temperature that could be different from something else. It does technically still have a temperature because there is radiation passing through it, and this radiation is left over from the Big Bang. The Big Bang happened everywhere in the universe at once because the universe was much smaller then, so that radiation is everywhere.",
"The only heat in the universe is from the CMB which is almost perfectly uniform, keeping the \"temperature\" of empty space about 2K (or °C) abow absolute 0. The CMB is the background radiation from the first hydrogen atoms formed the universe was pretty uniform than so the CMB's temperature is also pretty uniform, there are a few hotter and colder spot but the deviation is only a few tenth of a kelvin. However the temperatures around the universe can change a lot from stars to cold asteroids. In the Solar System the hottes place is on Earth usually when we experiment with fusion heating plasma to 150 000 000°C. On average it would be the Sun's core with 15 000 000°C."
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ntuu0w | What are compressed and uncompressed files, how does it all work and why compressed files take less storage? | Technology | explainlikeimfive | {
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"File compression saves hard drive space by removing redundant data. For example take a 500 page book and scan through it to find the 3 most commonly used words. Then replace those words with place holders so 'the' becomes $, etc Put an index at the front of the book that translates those symbols to words. Now the book contains exactly the same information as before, but now it's a couple dozen pages shorter. This is the basics of how file compression works. You find duplicate data in a file and replace it with pointers. The upside is reduced space usage, the downside is your processor has to work harder to *inflate* the file when it's needed.",
"Lets say I have a file that contains following: aaaaaaaaaaaaaaaaaaaa I could compress that like this: a20 Obviously it is now smaller. Real compression comes from redundancy and from the fact that most data is wasteful in the first place. A byte is 8 bits and thats basically the smallest amount of data that can be moved or stored. How ever, if you type a message like this, this only contains 26 different letters and some numbers and punctuation. With 5 bits you can encode 31 different characters, so we could already compress the data a lot. Next level is to count the letters and notice that some are way more common than others, so lets give shorter bit lengths per character for those. You can look into Huffman coding for more detailed info. Another form of compression is lossy compression which is used for images, videos and sound. You can easily reduce the amount of colors used in the image and it would still look the same to humans. Also you could merge similar pixels into same color and say that \"this 6x6 block is white\".",
"Suppose you're writing a grocery list. Your list initially says this: I need to get 6 eggs I need to get 2 liters of soy milk I need to get 2 liters of almond milk I need to get 1 pound of ground beef There's a lot of repetition in there, right? A smart compression algorithm would recognize that, and might render it like this: I need to get 6 eggs 2 liters of soy milk 2 liters of almond milk 1 pound of ground beef An even better compression algorithm might be able to further improve things: I need to get 6 eggs 2 liters of soy milk almond milk 1 pound of ground beef This is basically what compressing a file does. You take information that's repeated multiple times and remove that repetition, replacing it with instructions on how to put it back when you need to reconstruct the original content.",
"I like the text examples One for movies or animations is where they only save what changes between the frames. So if you have 100 frames all black, change them to one black frame and set it so that it takes up the same length of time as the 100 frames did. If you have a shot with blue sky, and it doesn't change because all the action is going on in the lower half of the frame, save the blue part of the frame and lengthen it/draw it out the same way as was done with the black, once something moves, only then do you have something you need to keep. This can be done for 10000 frames in a row, or it can be done if there are 2 frames with only 10% of the screen the same as the one before it.",
"Compression works by finding patterns in the data and then storing those patterns instead of the data itself. There are lots of different way to do this and a lot of different theory involved but it is the basic principle. Compression does work better when the compression algorithm is built for the specific file type. So a generic compression algorithm that is made to work on any file does not work as good on say image files as a dedicated image compression algorithm. Some algorithm might even opt to lose some information that is not important and does not fit into an easy pattern. This is most common in image and video where the exact value of each pixel is not that important. Compression algorithms also do not work if there is no patterns to the data. So random data, encrypted data or already compressed data can not be compressed any further.",
"Software programmer here. Like all binary data, files are stored as a series of 1's and 0's. Now imagine you had a file that was just a million 1's. If you wanted to describe this file to someone, it would be a lot smaller to write \"a million 1's\" instead of actually writing out \"1\" a million times. That's compression. More formally, compressing a file is actually writing a program that can write the uncompressed file for you. The compressed size of the file is then the size of that program. Decompressing the file is actually running the program to build your uncompressed file. More structured data like a large rectangle of a single color compresses well because it is easy to write a program that describes that data. On the other hand, random data is not very compressible because it does not have any structure and so you can't do much other than have your program actually write out the entire number, which is not going to be any smaller than the entire number itself. This is also why compressing a compressed file does not save more space. You can think of compression like squeezing juice out of a lemon, where the more structure that exists in the file, the more juice there is to squeeze, but once you have thoroughly squeezed it, there is no more juice left. Compression turns highly structured data into low structured data, so then when you compress again, you are dealing with random-ish data that doesn't have enough structure to take advantage of. You can also turn this backwards, and attempt to talk about how random some data is by measuring how easy it is to compress. There are two types of compression. The type I described above is lossless where the uncompressed file is exactly the same as the original file. Lossless algorithms are typically not that complicated and usually look for large areas of the file that share structure, like I mentioned above. Zip files are lossless. The other type of compression is lossy, where the uncompressed file does not have the same data as the original file, but has some sort of acceptable amount of data loss built into it. In return, lossy algorithms are far better at reducing the size. Lossy algorithms can be very complicated. JPEG and MPEG files are the main example of lossy compression. From personal experience, if you save a BMP file as a JPEG file, it will tend to be around a tenth the size of its BMP file. However, the JPEG file will not be the same pixels as the BMP file. The compression algorithm for JPEG files have been specifically tuned for photographs, so if you see a JPEG photograph you probably won't be able to tell that some pixels have been altered. However, for something like digital art, especially pixel art, it is much more noticeable, so you should never save digital art as a JPEG.",
"I have actually implemented file compression technology, so I feel particularly authorized to answer this question. Software needs to see files whose contents it understands. This is why software authors design file formats to be optimized to the particular needs of the particular problem their software is designed to solve, be the files written documents, audio/video recordings, spreadsheets, executable programs, scripts, etc. These needs do not necessary take into consideration file storage resources. So, when a user's file storage space is filling up, it's often in their interests to find ways to store **the exact same data** in a **smaller space**. That's what a data compression file format does. It is a way of analyzing the content of a file, identifying *self-similar parts* of that file (that's important), and recoding the file to take advantage of the fact that it can reduce the redundancy within the file to be able to store the content of the file in its own, compressed file format, which takes up less space, which is the whole point. Disk storage is not the only place where data compression is useful. Network transmittal of data benefits in taking less bandwidth and/or less time to transfer data from one place to another, if the data is compressed at one end and decompressed at the other. This, of course renders the data into a file format that the software which originally understood the file's contents no longer understands. This is the reason compressed files are given new filename extensions, so that even at the File System level, it becomes obvious that the contents of a file are compressed and so no one, human or software, makes the mistake of trying to operate upon that file's contents as if they were only encoded in the original, inner file format. Sometimes, this can be handled at the File System level, wherein the software responsible for reading data from or writing data to the actual storage media is the layer of software that takes responsibility for compressing the file's contents on write, and uncompressing the file's contents on read, which has the benefit that the file can be stored in its compressed state, consuming less space, while the original software is free to consume the file's contents, seeing only the file format that it expects. Often, software will expect its files to be compressed by external programs and so it can be architected to allow itself to be configured to detect compressed input and transparently pass the file through the appropriate decompresser program before trying to use the file's contents. Because one of the goals of compression is to reduce the redundancy of the encoded data, the compressed results have less redundancy to begin with, and so it's not possible to compress already compressed data to get the file even smaller. In fact, trying to compress already compressed data will often result in a doubly compressed file that's larger than the singly compressed file. This is due to the compression file format's meta data overhead, as well as other factors. This is often true even when two different compression schemes are used in tandem, not just reapplying the same compression scheme multiple times. Some file formats, for example audio/video recordings, are already encoded in some manner of compressed form. These are often \"lossy\" compression standards, such as JPEG or MP3, that explicitly throws away some data in order to make the image or video or audio appear identical when consumed by a human, while also rendering the data into a form that is more amenable to compression. It's fine to recode a \"lossless\" audio file to a lossy one, if the human ear will not be able to tell the difference between the playback of the lossy and the lossless encodings. Other data types, for instance executable program code, would not be amenable to lossy data compression, since actually changing the details of the instructions in the program would likely be fatal to the execution of the resultant compressed-decompressed program. For such lossless data compression schemes, it is paramount that the round-trip conversion of < original data > (compression) < compressed data > (decompression) < uncompressed data > give the result that < original data > and < uncompressed data > be bit-for-bit identical. There are many different compression schemes at work in the world. Each one does what it does in slightly different ways. It is impossible to create a single compression scheme that works equally well on all kinds of data. The compression scheme at work in MP3 files is actually so specialized that it's covered by a patent owned by the Fraunhoffer Institute. However, as adept as the compression scheme in MP3s is at compressing audio data, it would not work nearly as well for spreadsheets or written documents. Likewise, the kind of compression schemes that might work well on written documents would work very poorly for video streams. The diverse needs of different types of data and the continual research and development of computer algorithms insures that there will always be a new file compression extension to learn sooner rather than later.",
"Imagine you want to save a message: AAAAAAAAAA AAAAAAAAAA AAAAAAAAAA AAAAAAAAAA AAAAAAAAAA BAAAAAAAAA AAAAAAAAAA AAAAAAAAAA AAAAAAAAAA AAAAAAAAAA It takes 100 characters to save it. You could save it as: 50*A,B,49*A And have it saved 11 characters. This is lossless compression, and a kind of thing (though obviously a very primitive version) that, say, 7zip or winrar do. You could imagine a different algorythm that saves even more space: 100*A And voila, you saved your message in 5 characters. Well, not exactly your message, you lost the B, but it's very close to the message, maybe reader wouldn't notice the B anyway. This is \"lossy\" compression, where you sacrifice some information the original had in order to save even more space. This is (a very primitive version of) what saving an image as JPG or music as MP3 does. Of course, these formats are popular because they are very good at only loosing the information humans actually don't notice, but idea is the same.",
"Just a fun example of compression. I used the zen of python. For simplicity, I removed all punctuation and made it lower case. I'm sure there are better ways to compress this as well. Original: 807 bytes > beautiful is better than ugly > > explicit is better than implicit > > simple is better than complex > > complex is better than complicated > > flat is better than nested > > sparse is better than dense > > readability counts > > special cases arent special enough to break the rules > > although practicality beats purity > > errors should never pass silently > > unless explicitly silenced > > in the face of ambiguity refuse the temptation to guess > > there should be one and preferably only one obvious way to do it > > although that way may not be obvious at first unless youre dutch > > now is better than never > > although never is often better than right now > > if the implementation is hard to explain its a bad idea > > if the implementation is easy to explain it may be a good idea > > namespaces are one honking great idea lets do more of those Compressed generated with some code: 709 bytes > \\[\\~=is;!=better;@=than;#=the;$=although;%=never;\\^=idea; & =complex;\\*=special;(=should;)=unless;{=obvious;}=it;|=implementation;\\\\=explain\\] > > beautiful \\~ ! @ ugly > > explic} \\~ ! @ implic} > > simple \\~ ! @ & > > & \\~ ! @ complicated > > flat \\~ ! @ nested > > sparse \\~ ! @ dense > > readabil}y counts > > \\* cases arent \\* enough to break # rules > > $ practical}y beats pur}y > > errors ( % pass silently > > ) explic}ly silenced > > in # face of ambigu}y refuse # temptation to guess > > \\#re ( be one and preferably only one { way to do } > > $ that way may not be { at first ) youre dutch > > now \\~ ! @ % > > $ % \\~ often ! @ right now > > if # | \\~ hard to \\\\ }s a bad \\^ > > if # | \\~ easy to \\\\ } may be a good \\^ > > namespaces are one honking great \\^ lets do more of those Compressed after manual modification: 673 bytes > \\[\\~=is;!=better;@=than;#=the;$=although;%=never;\\^=idea; & =complex;\\*=special;(=should;)=unless;{=obvious;}=it;|=implementation;\\\\=explain;:= \\~ ! @ ;'= # | \\~ ; < = to \\\\ }\\] > > beautiful:ugly > > explic}:implic} > > simple: & > > & :complicated > > flat:nested > > sparse:dense > > readabil}y counts > > \\* cases arent \\* enough to break # rules > > $ practical}y beats pur}y > > errors ( % pass silently > > ) explic}ly silenced > > in # face of ambigu}y refuse # temptation to guess > > \\#re ( be one and preferably only one { way to do } > > $ that way may not be { at first ) youre dutch > > now:% > > $ % \\~ often ! @ right now > > if'hard < s a bad \\^ > > if'easy < may be a good \\^ > > namespaces are one honking great \\^ lets do more of those & #x200B; Edit: Dang reddit messed up my formatting. Should be fixed now",
"Compressing and uncompressing a file is like translating a book into a different language, except you make up the language based on what's in the book. To make files smaller, you have your new language use very short words for the most common words or phrases in the original language, and longer words for the uncommon ones. Then you have to make the dictionary that translates back to the original language, or figure out rules so that you can construct the dictionary, and then the compressed file is the translated file plus the dictionary. In most cases the compression method (or translation) is chosen to be very good for \"normal\" files, but bad for \"uncommon\" files that you generally wouldn't encounter. Mathematically you can't have a one-to-one translation that converts every possible combination of letters into a shorter form, because then some combinations would have the same translation and you wouldn't know which one was the original when you translate it back. If you don't need *exactly* the original file because it's something like a picture, you can have a translation that is always shorter, but in general if you try to compress an already compressed file it doesn't get smaller."
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ntuz74 | How strong is the earth's magnetic field? | Physics | explainlikeimfive | {
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"Magnetic fields are measured in Gauss (small fields) or Tesla (big ones). Earth's field is 0.25-0.65 Gauss depending on where you are, or about 25-65 micro Tesla. A fridge magnet is about 0.05 Tesla or 500 Gauss...about 1000 times more powerful than the earth's field. So the earth's field is really weak. But it's \\*huge\\* and pervasive, it's everywhere. That's why small magnets will screw with your compass if they get close but don't have any meaningful effect if you move them a little bit away.",
"The thing with magnetic fields is that they decay very rapidly with distance (they are very weak when you get far from the source). You can see that by yourself with any magnet, they are able to lift pretty heavy objects, but if you move it from 10cm away from the object it does nothing. Earths magnetic field is strong in a way, because it surrounds a whole planet and is able to influence things at a very far distance. But when speaking of the force it can exert on a clip, it is small. To give you some numbers: a Neodimium magnet, one of the strongest, but not rare, has magnetic field of 1T right on the surface. Earths magnetic field is arroun 30uT which is 10,000 times lower. So at the small scale in the surface of the earth, prety much any magnet is more powerful. But taking into account Earths size, its magnetic field is vast."
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ntv25a | why does skin develop wrinkles? | What happens to the tissue such that wrinkles develop with age? And how come, if cells replace each other, this wrinkles stay? | Biology | explainlikeimfive | {
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"When you're young your skin is stretchy and will shrink down to just the size of what's inside it, but as you get older, it loses its elasticity and stays \"bigger\". It's still attached, though, and the \"excess length\" has to fold up to fit."
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ntwsoq | how do countries owe money and who do they owe it to? | Economics | explainlikeimfive | {
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"They issue bonds and owe the bond holders. Bond holders can be you and me or a financial institution or another country. The terms of that bond are set by the country and can be repacked, resold by any of the bond holders by whatever terms they wish but the issuing country will only pay out on the original set of terms. The country issuing the bond determines the amount of risk someone is assuming."
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nty888 | How do we actually know what vitamins and minerals are in the foods we eat | Bananas , sweet potatoes , and squash, are all high in vitamin k. Aside from Google and health books, how can we find those vitamins and what do they look like ? | Chemistry | explainlikeimfive | {
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"We have data from processing samples in a Mass Spectrometer. The sample is broken down into its chemical components and the spectrometer identifies the quantities of each chemical. So we get the exact amount for the small sample and the scientists scale up and give an educated guess as to how much for a full serving/individual food.",
"You can take the items of food to a lab and run different experiments on them. That’s pretty much it. Per FDA rules the nutrition information doesn’t have to be 100% correct on the package, just within a reasonable % or a few grams. This means that a good producer can just test one batch and then safely assume that every batch that is made the same way with the same ingredients will have relatively similar standards. For when you look up how many calories, say, an orange is. All that does if pull from a database a number that an orange that had been tested before gave (or the average from a bunch of oranges). But that number isn’t goin got be the perfect number for your orange, if it’s a bit bigger or smaller, but it’s close enough."
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ntyaue | Newton’s Cradle | I guess this is a two part question. 1) Since Newton’s Cradle follows CoM and CoE, shouldn’t there be a point where one fast sphere on one side can be transformed into two spheres with half the speed? 2) If the spheres have different masses such as the two spheres on the left is 0.5kg and the two spheres on the right is 1 kg, would two spheres on the left move exactly one sphere on the right? Thanks! | Physics | explainlikeimfive | {
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"Well lets do the math. Assume the ball is of mass m. v is the speed of one ball just before it hits the other balls. The momentum is mv. The energy is 1/2 m v^2. We can transfer the momentum to 2 balls with half of v as you say, because mv = (2m)(v/2). CoM is preserved. But lets see if this works for energy as well. 1/2 (2m) (v/2)^2 = 1/2 (2m) (v/4) = 1/4 mv^2 . This is not the 1/2 mv^2 we are expecting for energy, its less. Your idea violates COE. Note its not impossible, as this system loses energy, not gains energy. Under the right conditions this can happen and the energy would be dissipated as heat. But Newton's cradle is a near perfectly elastic collision, meaning it preserves both COE and COM.",
"1. The energy from 1 moving bal is transferred thorough to the last ball which has nothing to transfer energy to. So you'll continue to see only 1 ball on each side move until enough of the energy had been lost that the ball on the end isn't getting enough to separate it. 2. Following the principle established in (1.) I'm pretty sure if you start the reaction with a ball on the heavy side, the ball on the end of the lighter side would just get fucken launched because of how much energy it receives. The second ball on the light side might also move if there's enough force being transferred, but not enough to classify it as equal amounts."
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ntywkw | How do torches burn consumable materials like cloth or wood at a slower pace while still producing light and heat at useful levels? | Chemistry | explainlikeimfive | {
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"Torches, like candles, burn a combustible hydrocarbon, often tar, pitch, animal fat or some sort of oil. The cloth serves as a wick and a “container” for the fuel and not as the source of light.",
"The wick has a higher ignition temperature than the fuel that it's soaked with, so the fuel burns but not the wick. Capillary action (the effect that causes a liquid to spread through material like cloth) continually draws up fuel from the reservoir as it burns away."
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ntzsh4 | Golf Balls. | When you see someone barely miss a put you see the golf ball pick up speed on the rim, where does it get the boost from? | Physics | explainlikeimfive | {
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"It doesn't actually have more speed when it leaves the hole, but it can be much faster as it's zipping round the rim. The reason is that it's actually falling into the hole a little bit. Gravity is pulling it down, which makes it go faster, but it manages to stay out the hole. Basically, it's an orbit, like a comet that speeds up when it's close to the sun and then zips away. Have you ever seen one of those sorta cone shaped charity box things where you roll a coin in and it spins round and round? Sometimes, the coin heads a bit too steep towards the middle. This makes it speed up, which makes it hook back out to the height it came from. As it's moving back out, it slows down. It's the same thing with the golf ball, but far more annoying!"
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ntzshz | How do antibiotics so efficiently kill bacteria in our systems, but doesn't attack our cells? | Biology | explainlikeimfive | {
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"Antibiotics hurt certain parts of bacteria, making them unable to survive. These parts targeted do not exist in human cells, posing no risk",
"Bacteria have a *very* different biology than animal cells. Not only are they single celled organisms, but they don't have a nucleus or organelles, no mitochondria, no cytoskeleton, and they have cell walls which are very different from animal cell membranes. They are also very tiny compared to animal cells. In fact, for a long time, bacteria were classified as plants. That's how different they are from animal cells. So, you exploit these differences to kill them. For example, penicillin inhibits bacteria from making a key component of their cell walls. Without a cell wall, they are just free floating goo that can't reproduce. And remember, animal cells don't even have cell walls. So penicillin just goes ham on their cell wall machinery, destroying them completely, and it has little to no effect on your own cells."
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ntzvg1 | what happens to stocks when a public company goes out of business? | I don’t know much about stocks but I know it’s more tied to how well people think a company’s doing than how well it actually is. If some big company was struggling but hid it and then just crashed and went out of business what happens to the stocks? Do the stocks just drop to 0? Do people get their money back at the last stock price? I’m thinking about something like Door Dash or a tech company where it’s not totally clear how well the companies doing and they post all these unclear articles about how well they’re doing even though the numbers are sketchy. Obviously everyone could tell if like Walmart or McDonalds was failing. I know big industries like banks etc. usually get bought out for cheap by someone else who does the same thing, but something like Door Dash, who would buy that? It’d just go out of business like Blockbuster wouldn’t it? | Economics | explainlikeimfive | {
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"> just crashed and went out of business what happens to the stocks? Do the stocks just drop to 0? Yep. > Do people get their money back at the last stock price? From where exactly do you imagine that money would come from? There is no fund for compensating failed investments. > If some big company was struggling but hid it This complicates matters a bit because this would be fraud, and the people who hid it would be sued into oblivion. But that doesn't recover the value, it just punishes the wrongdoing. > a tech company where it’s not totally clear how well the companies doing This is why there are periodic reports to the investors which the management is required to do, and to be truthful about under force of law.",
"If the company goes bankrupt the stock goes to zero and the shareholders they nothing. The shareholders have the most risk. They have no claim on company assets other than whatever the shares are worth at any given time. But they also stand to make the most money - potentially huge amounts if the company does really well. But if the company goes bust they’re left holding some worthless defunct share certificates. This is in contrast to a Bond holder who loans the company money with an agreed interest rate and repayment schedule - they have a maximum, fairly modest, profit from their investment, but if the company goes bankrupt they’re fairly close to the front of the line to get something from the liquidation of any assets.",
"When a public company goes out of business it goes through a process to pay off any other companies or people any debt it owes and tries to sell off any assets it owns. After paying everything off, if any money is remaining, it’s dispersed to its owners, the stockholders. It could be nothing, it could be like $0.01 per share."
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nu07vo | Why do we remember bad/stupid things we did only a while after they happened? | I've done very stupid things throughout my life, but those memories only haunt me years later and not within the same year they happened. Is there a reasonable explanation for this phenomenon? | Other | explainlikeimfive | {
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"Your brain is wired to respond to threats and remember them to avoid them in the future. Stupid errors that affect your social status or well being are a type of threat. The emotional value of the event makes the memory even stronger.",
"Most of us did stupid things when young, and didn’t realise they were stupid until we grew up and realised how lucky we are to be alive! But there’s plenty of stupid things we do that we regret immediately after. Like scratching my watch face for example. That only happened an hour ago and I’m kicking myself."
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nu0hn1 | Why does a pen dry faster when its clicked out? It's still exposed to air when it's clicked it. What's the difference? | Other | explainlikeimfive | {
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"They don’t. The pens that “click out” are ball point pens. They click in and out so that you don’t accidentally draw all over yourself."
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nu1o92 | why does very cold bottled water look unfrozen if you don't do anything to it, but starts to freeze when you open the cap? | I'm not quite sure how to properly phrase my explanation so I'm going to try my best So if you take a bottled water and put it into the freezer, wait until it's very cold (but not completely frozen), and then take it out, why does it only start to solidify and freeze when you open the cap? It's like, the water still looks transparent like a liquid when you take it out, but as soon as you open the cap or like, just set it in room temperature, it starts to look "icy" like a normal frozen water that kind of creeps in first from the bottom all the way to the top My bad if this is poorly explained | Physics | explainlikeimfive | {
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"This process is called supercooling. The water is below its freezing temperature but due to a combination of factors, namely lack of a nucleation sites (places the liquid can start crystalizing) and or pressure inside the bottle (mostly nucleation sites) the water is unable to actually crystallize. This is why when you open the cap, tap it, or shake it hard enough, you change the equation and it can freeze. Since the water is below freezing already the transition is almost immediate, you can watch the ice form rapidly. Side note, water will 'spontaneously' freeze at around -39 degrees Celsius regardless of nucleation sites.",
"It's called supercooling. URL_0 Basically, ice needs a crystal or nucleus to form on. If water is cooled properly, it basically turns into a glass like state. Since the water is below freezing, agitation or exposure to air can provide the necessary attachment point or nucleus."
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nu1vyn | Why are we all being contacted about our extended car warranty? | Other | explainlikeimfive | {
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"Scam phone calls, they are hoping you'll return the call and give them more information than they could possibly already have in order to \"extend your warranty\" (i.e., steal your identity).",
"Because we’ve tried to reach you by mail, but you have not responded. This is your final notice.",
"Bigger question: why is the government doing fuck-all to stop it?",
"So others have already rightfully answered that these are obvious scams. But why an extended car warranty? Probably just because it works, so others have copied it. It actually makes a lot of sense - most people (or at least a large % of people) own cars. So they can call any random number and there’s a very good chance that person owns a car. If they told you they were trying to contact you about your home warranty or a vacation you recently booked, you can quickly identify it as a scam if neither of those two situations apply to you. But if you own a car and you’re not familiar with this scam, there’s a good chance you’d at least consider that it may be a legitimate call. Also, car warranties DO expire. So once again, the premise behind the call is actually very reasonable. The only reason that these calls are instantly recognized as a scam is because we get them all the time. Or think of it this way - if people can be fooled by something as absurd as the Nigerian Prince scam, an expired car warranty scam seems very reasonable.",
"Someone is making money from the calls. It must work every now and then because the calls keep coming.",
"Not sure if this is OK to do but have a listen to this episode of Planet Money. It goes into the history of extended warranty sales and explains a lot of it. URL_0",
"In New Zealand we get scam calls from \"Windows security\" or \"Spark technical department\" - Spark being our oldest teleco",
"TIL: I’m not actually being obsessively contacted multiple times a week by my car’s manufacturer for a car I purchased almost a decade ago and quite obviously have never wanted a warranty for, it’s likely an unrelated scam party. Obvious in hindsight but for years I’ve just believed it’s an unethical and ridiculously overkill ad campaign. Over time it’s changed my perceptions because I’ve figured if it’s worth it to advertise this that much then I assumed car warranties were far more popular than I expected",
"I just listened to a podcast about a month ago that explained it extremely well: URL_0 . For those who don’t want to listen to the episode, here’s what I remember: 1. A pair of brothers created a “company” offering a poorly worded contracts about an extended warranty for their older vehicle 2. Most claims against the “warranty” were subsequently denied, making them lots of money 3. They aggressively hired people to sell as many of these things as they could 4. They built mansions next to each other 5. They’re now in jail because of all of the laws that they broke doing this predatory practice 6. We’re left with the messy aftermath"
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nu29k8 | How do savings get wiped out in a market crash? | I'm specifically talking about money in the savings account. Lets say I have 1k in my savings account in a bank (we can assume its USA since I'm specifically interested in this context). Do they just disappear? | Economics | explainlikeimfive | {
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"Oh no that money doesn't get wiped out.its actually in a low risk account and federally insured by the bank. You're good to relax",
"As the others have explained, savings accounts are generally safe, because the banks invest those in \"low risk\" things like precious metals, that don't fluctuate all that much. However, if you're playing with the stock market yourself, and are using your savings to invest, especially in high-risk things like hedge funds or crypto-currency, if the markets crash and the things you invested into lose their value, you can lose your money big time. To give you specific numbers, look at [gold]( URL_1 ) it's more or less holding around $23, with a variance between $18 and $25, so your $1000 savings would fluctuate between $780 and $1100. [Bitcoin]( URL_0 ), on the other hand, went from $30k to $60k and back to $30k, so you could have doubled your $1000, or halved it to $500, depending on timing.",
"Savings don't get wipes out. Back in the 1929 crash, banks failed when there were bank runs and they didn't have enough cash on hand to pay out. Now, checking/savings accounts are protected by FDIC insurance up to $250k, so there is no risk of losing your $1k in a savings account. Worst that could happen is a bank fails, the government spends a day getting another bank to take over the accounts and begin administering them and you'd have access again.",
"Your money in a regular bank or credit union account is insured. Each account is insured up to $100,000. Money gets \"wiped out\" when markets crash when that money is invested in stocks and bonds (which are two separate things completely, but they are associated together). A lot of people have money in these because they provide much better rates of return (you can actually *make* money compared to just saving them in a bank account), and a lot of peoples' money here are in retirement accounts - it's money they're hoping to use when they're old and don't want to work any more. These investments are *not* insured. So if you have $100,000 and the market takes a dump and you lose half of that... well, now you only have $50k in your portfolio. Given time it's possible that you could recover some or all of that, and if you're younger that's not as serious of a deal, but when you're older relying on steady payouts from your account it can cause a headache to say the least, because... you don't have that time to recover."
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nu33kn | Why is immigration important for economic growth? | Reading in another post about Japan's high national debt and economy stalling, lots of comments were about how not allowing much immigration is a big factor. please explain like I'm 5 because I literally don't get it. | Economics | explainlikeimfive | {
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"Japan has a decreasing population because their people aren’t having enough kids. More people are dying than there are being born. So, as people retire, there aren’t enough young people entering the workforce to replace them. This means that there’s a disproportionately elderly population. This is exacerbated by Japan’s high life expectancy; there are going to be more old people if people live longer. With more retired people due to an aging population, there needs to be an even larger workplace to support them. However, that isn’t happening because, again, people aren’t having kids. So, if people aren’t making children who will eventually join the workforce, countries need to let workers in via immigration. Due to its strict immigration policy, Japan isn’t letting enough people in to restore the balance of their population, leading to economic problems.",
"I'm not an expert in this field, so take whatever I say with a grain of salt. One reason is an aging population. [Here]( URL_1 ) you can see a population pyramid of Japan as it is right now in 2021. As you can see, the younger population is a bit bigger than the older population. Play around with adding years, and you'll see something troubling: more and more old people, less and less young people. Old people need to be cared for by the younger generations. That costs money, most of that paid for by taxes. Taxes are gained when people pay them, and most taxes are earned by people working a job. More old people = > less people in the workforce paying lots of taxes = > not enough money and personel to pay for the old people. Government either needs to drop support for old people (not very popular considering they will be/are a huge part of the electorate) OR they need to increase taxes (also not very popular...) OR they need more young people to work to pay taxes and care for the previous generations. Immigration is just one way to solve this problem. There are lots of articles about China facing the same problem. China grew incredibly fast the last few decades, and its [young demographic certainly helped]( URL_2 ). Now keep adding years, and you'll see that China will eventually face a similar (albeit not as bad as Japan) situation. The same has been happening in European countries but not as badly in Japan (Europe isn't against immigration, but also not very pro either), and only a little bit in the United States. Japan isn't very open to immigration at all. Immigration on its own isn't necessarily always good for the economy. But in these modern times, in which people live longer because of better lives and technology, and in which adults don't have the time/can't afford/don't want to have multiple children resulting in lower fertility rates, immigration is pretty important to pay for the older generation's care. Now take a look at [India]( URL_3 ) and [Indonesia]( URL_0 ). Keep adding years. What you'll actually see is their economic development. If their economies develop as much/the same way as richer countries have, they'll eventually look like China/Japan/Europe too."
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nu3753 | what exactly do animals do to their skin when they camouflage? | Biology | explainlikeimfive | {
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"Most animals' camouflages are passive, meaning that it is their natural state, and they are only considered camouflaged because they match their environment or they mimic another animal. There are a couple of animals that have developed a more active kind of camouflage. Some cuttlesfish and octopus have layers of little color sacks on their skins that they can expand and contract on demand, creating not only different colors, but also different moving patterns and even mimicking texture, like roughness. There is also a form of camouflage that uses bioluminescent lights to blend into lit backgrounds.",
"They have layers of skin with special cells that can become opaque. By triggering these cells in various layers they can blend them into making a lot of different colors. The special cells are called \"chromataphores\""
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nu3bpj | how we know Jellyfish have been around for 500 million years? | Or how cyanobacteria have been around for 2 billion plus? How do we know so unequivocally what roamed the earth (and the seas) half a billion years ago or more? | Biology | explainlikeimfive | {
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"We know that Jellyfish has existed for 500 million years because we have found fossils of them that are that old [ URL_0 ]( URL_2 ) Ther are fossils of cyanobacteria that are 1.9 billion years old. Here is a paper that looks at early evidence URL_1 It is believed that the existed 2.4 billion years ago during the greater oxidation even and might be a lot older but there is no unambiguous fossil evidence of it, or more exactly there was none when the paper was written in 2019."
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nu4ifi | How do pressure points work? What is actually happening at a biological level to make them a real thing? | Biology | explainlikeimfive | {
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"They are not really. There are certainly spots that are sensitive or otherwise distinguished in a way but there is no such thing in western science as \"pressure points\". Are you referring to martial arts, massages or something different?",
"martial art: certain nerve knots/spots make your limb go numb for a while. when the right amount of force is applied to that spot massage: certain nerve knots/spots help your bloodflow when the right force is applied to that spot."
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nu4zqf | How does the moon revolve in such a stable condition instead of crashing onto the earth or moving away from it? | Physics | explainlikeimfive | {
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"Because if it was unstable, it wouldn't be there. Many objects fell to the earth. Many objects moved away. Hence, we are left with one object which didn't.",
"The moon is in orbit. And orbits, generally speaking, are stable in the sense that small disruptions don't mess with them too much - they aren't a delicate balance that fails the second anything gets tweaked. And the Moon is big enough that something huge would have to happen to meaningfully affect its orbit around the Earth in the first place. Over very long timescales, the Moon is in fact moving slowly away from the Earth, but that's because of the way the force of the tides works out (roughly speaking, the Moon slows down Earth's rotation and transfers that energy to its own orbit, making that orbit slightly higher)."
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nu7l7h | why does it take minutes to burn down a house but trying to start a fire in the fireplace sometimes fails? | Bonus question. When you do start a fire and it's raging, why is it that sometimes the wood doesn't even completely burn up? | Chemistry | explainlikeimfive | {
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"Im no expert but I think this is selection bias. Sometimes that fireplace fire lights really quick. Sometimes it doesnt. Sometimes the house catches quick. Sometimes it doesnt. The one doesnt affect the other, and you dont hear about \"small fire outside house, lightly singed three boards\"",
"Materials. If you have a house made of stone, it probably won't burn and if you put dry straws in the fireplace, they will burn up very quickly. Most plastics burn very well and a typical house has a lot of plastics all over. Another issue is when you start measuring. In case of fireplace, you know exactly when you light the match. In case of a house, the fire there has probably burned for a while before anyone has noticed anything.",
"The physics is complicated but basically fire likes to burn a whole lot better when you don't want it to",
"The stuff you put in a fireplace to burn generally is stuff that is going to burn rather slowly, houses on the other hand are made of, and full of, stuff that can burn very quickly, stuff like carpet, furniture, cloth of any kind, etc all burns quickly. Another compounding factor is oxygen, the rate at which something burns is dependent on how much oxygen it can get. The fireplace is relatively small and confined, so oxygen has to flow into it, a house is more spread out so it’s already got lots of oxygen available.",
"To add to what others have said, fireplace logs are generally meant to catch and then slowly burn, not erupt in flame. Wood is also usually cut to a size and shape for a fireplace so that it will burn a certain way and not all the way down. A fireplace usually won't go above a certain size. Things like curtains and rugs will catch fire and burn brightly as well as grow out of control, leaping to other objects. The greater heat will make even wood used in houses burn stronger and hotter.",
"Fire need a lot of heat to spread properly. A small fireplace fire loses the necessary heat to the inverse square law after a couple of centimeters, but a house on fire causes enough heat to ignite other things with just a spark even meters away.",
"Multifuel stove owner here. To get your fire started you wants dry tinder with lots of surface area. I used fur from our dogs (my wife collects it when she's brushing them) and wood shaved from dry kindling. I few strikes using firesteel and a knife is enough to set it alight. It's just a small flame like a candle at this stage. Slivers of kindling go on top with plenty of air gaps so as not to smother the flame. Increasingly larger sticks are added. I will feather the stick with a knife to make it easier to catch. I only add logs once the fire has established itself. Once the stove is really hot - it can take an hour or two because it's heavy - logs burst into flames as soon as they're added.",
"You don’t *expect* the house to burn so you don’t pay attention to it. Meaning your perception of time from ignition to noticing a big fire is different. It’s like heating milk. When waiting for it it takes ages. If you walk away and are distracted you can clean up the mess.",
"If I were to take a guess, its probably because our houses usually are ventilated and have more oxygen supply than say a semi closed fireplace. Moreover thick and moist logs (due to humidity absorption) can be harder to burn due to increased ignition temperature. Also, there are things in our houses which are easier to burn due to lower ignition temperature than wood, like cotton clothes."
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nu7zts | How exactly do blood thinners work? | I know they stop clots but how exactly? By reducing the amount of haemoglobin? Or making it weaker? | Biology | explainlikeimfive | {
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"Haemoglobin isn't involved in clotting. Blood thinners change the structure of the bloodplasma in a way that it can't coagulate. A bloodclot is basically a bunch of platelets \"glued\" together with blood plasma. The blood thinner basically prevents this glue from drying. (The name \"blood thinner\" is misleading by the way, it doesn't actually make the blood thinner/less viscous. It really only prevents clotting)"
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nu86tq | how are NTFs bad for the environment | Technology | explainlikeimfive | {
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"NFTs themselves do not particularly use a lot of energy - they are simply a capability that exists within some cryptocurrencies to uniquely associate some data with a user, and transfer that association in a transaction. The environmental harm is not a result of this capability or any other transaction-related capability, but of the underlying blockchain consensus algorithm - the way everyone in the world agrees which transactions have taken place in the past. Currently, most cryptocurrencies use proof of work, which means that when a block (a list of all the transactions people are trying to make) is inserted, everyone tries to insert it at the same time by trying to compute a value associated with that block. The first one to compute it successfully gets to also insert a small transaction to themself, which is the motivation for trying to do it above and beyond simply wanting the network to continue running. This process uses quite a bit of energy.",
"NFTs are based on the same Blockchain principles as cryptocurrency. As such, they require a large amount of computer power to maintain, which means there's a large amount of electricity needed. One estimate was that a single NFT requires an amount of electricity equivalent to a month's usage for the average EU citizen."
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nu8ubh | Why do Tortoises live so long? | That's it. The question. I have zero knowledge about it and would like to know the reason. | Biology | explainlikeimfive | {
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"Found this Scientists believe the lifespans of giant tortoises like George are so long because they have gene variants that tweak how their DNA is repaired and their bodies respond to inflammation and the development of cancer. Prior to the study, little was known about the genes of these invertebrates",
"One of the theories, according to my biology of aging class I took many years ago, was the rate of metabolism. A tortoise's metabolism is so slow. The amount of free radicals that are created that build up in the body that potentially lead to death is also very slow. If an animal has a high/fast metabolism, they live a short life. However, there are exceptions to this rule, which is why it's still a theory, as far as I know."
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],
"text_urls": [
[],
[]
]
} | [
"url"
] | [
"url"
] |
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