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nr3qwc | Why does boiling water create bubbles in a pot? Was the water not already taking up the space? | Physics | explainlikeimfive | {
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"The bubbles are actually bubbles of steam. When the water at the bottom turns into steam it is now a bubble which then floats to the top as it is less dense than water. The water was taking up space, it is just the volume of a gas is higher than the volume of it's liquid form so it looks like a lot of bubble but it might be a tiny bit of the total amount of water in the bubble. These bubbles actually cause the volume of the water in the pot to decrease so the space it is taking up decreases in accordance to the amount of water lost to steam formation",
"Those bubbles are water vapor, steam. Since heat is applied at the bottom of the pot, that’s the hottest part, and where water evaporates into steam the quickest. There can also be gases dissolved into the water, like the CO2 disolved in your soda, but typically these are quite small amounts.",
"The bubbles that form are still water, just water as a gas rather than water as a liquid. These bubbles are always forming throughout the liquid water. However, the pressure of the liquid water is strong enough to immediately collapse the bubbles that form whenever the liquid water is below it's boiling point. Once the water temperature reaches the boiling point, the pressure inside the bubbles that form is high enough that it pushes back against the liquid water enough that it doesn't collapse."
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nr3ypo | Why can’t we hear ourselves snoring? | Biology | explainlikeimfive | {
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"If you're awake enough to notice and remember your farts, then you're awake enough to keep your airway open. Muscle tone doesn't usually slack off until later stages of sleep. But if your sleep is really off, and you fall straight into REM, you can wake yourself up with snoring, or by a sudden shift in position when your muscles suddenly relax. I've done it. But it's not necessarily the sound of the snoring. If you're awake enough to hear the snoring, then you're awake enough to feel it."
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nr4hpu | Why do computer screen images look weird when pressed on but not just in text? | If you take a picture of a computer screen, and send it to someone, without pressing on the image it’ll look completely fine, but when they press on the image it shows a grid type of texture on top of the image. Why? | Technology | explainlikeimfive | {
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"I'm guessing by \"pressed on\", you mean zoomed in to full size? The grid texture you're seeing is what's called a Moire pattern. Your camera is actually high enough resolution to be able to see in between each of the pixels of your screen (and possibly even the red, green, and blue sub-pixels that make up the pixels). If you take a magnifying glass (or look *very* closely) to your screen, you'll be able to see the same gaps in between the pixels. But, you're not going to see that same pattern you see in the picture you took. Why? Because our eyes don't work on a grid pattern. When we look at something directly, we're able to discern all the details we want based on how close or how magnified we want it. Any lack of detail will just blur itself out because it's not able to be focused as well on our rods and cones in our eyes, which aren't really laid out in any distinguishable pattern (and *definitely* not straight up/down lines). For a camera, it's different. It has a very strict grid that it measures the light with, so if *another* pattern lines up weirdly with it (like the grid of the pixels on the screen), you're going to see an interference pattern happen with the image you take. This is the Moire pattern. Also, when you are viewing that same photo at a smaller size, you won't see the pattern any more because groups of pixels get blurred together to show a smaller version, meaning all the details of the grid get washed out and lost (check out bilinear or trilinear filtering if you want to learn more about this)."
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nr4ihm | When an embryo is forming, how do the cells know which parts to turn into? | I'm not entirely sure, because embryos are formed by the replication of cells, right? But since all the cells are clones of each other and as far as I know have the same DNA, how do certain cells know where and when to start developing body parts if they are all the same? I was going to just assume that it had something to do with some other outside factor, but I would be glad if someone could explain to me in a concise way since my understanding here might be super flawed. | Biology | explainlikeimfive | {
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"So it boils down to signal cascades. As cells get further seperated, the cell to cell signal molecules and proteins decrease in gradient. This low gradient in the more distal cells might mean it starts expressing different genes. And the products of this might influence the way the cells around it develop as well. There is much more to it but the simple version is cells communicate and the molecules they use to communicate tell them to express certain genes or to suppress other ones. When cells divide and get distant the signaling strength changes and the genes expressed may change."
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nr4xbf | What is disassociation and how would you know that it is happening to you? | Other | explainlikeimfive | {
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"Im going to pressume this is in regard to mental health... Disassociation is thought to be a preventative measure the brain takes to ease the effect of serious trauma. This is called peritraumatic disassociation. Think of a time when something is really horrible and you don't want to pay attention to it, but you do because your human. When you disassociate your brain basically says \"This is WAYYYYYY too much to handle. I don't care, let's slow down time a bit, please try again later\""
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nr4yer | how does 1s complement subtraction algorithm work? | The step by step process was explained to me but Im not sure why it works. | Mathematics | explainlikeimfive | {
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"Looking at the link you gave it's no surprise you're confused, it's like he's deliberately trying to make it bad. The idea is this: Say you want to figure out what 15 - 10 is. This is the same as figuring out what 15 + (-10). 15 in binary is: Sign | 8's | 4's | 2's | 1's | Decimal ---|---|----|----|----|---- 0 | 1 | 1 | 1 | 1 | 15 10 in binary is: Sign | 8's | 4's | 2's | 1's | Decimal ---|---|----|----|----|---- 0 | 1 | 0 | 1 | 0 | 10 to get negative numbers in 1's complement you just flip every digit Sign | 8's | 4's | 2's | 1's | Decimal ---|---|----|----|----|---- 0 | 1 | 0 | 1 | 0 | 10 1 | 0 | 1 | 0 | 1 | -10 Now just do the long addition Sign | 8's | 4's | 2's | 1's | Decimal ---|---|----|----|----|---- 0 | 1 | 1 | 1 | 1 | 15 1 | 0 | 1 | 0 | 1 | -10 1's place is 0, carry 1 2's place is 0, carry 1 4's place is 1, carry 1 8's place is 0, carry 1 signs place is 0, carry 1. Since there was a carry from the signs place, we move that carry to the 1's place. That's a quirk of one's complement. so we end up with: Sign | 8's | 4's | 2's | 1's | Decimal ---|---|----|----|----|---- 0 | 0 | 1 | 0 | 1 | 5 One thing to note though, I can't really name any modern computer system that uses's one's complement Most use two's complement. Which works roughly the same way, except to get a negative number, you flip all the digits and add 1. And you just discard the sign's carry digit."
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nr6vnh | What is Auth-Left? | Economics | explainlikeimfive | {
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"\"Auth-left,\" or the authoritarian left, is used as a shorthand to describe authoritarian socialists. A lot of the people who fall under this label are Marxist-Leninists (i.e., the official ideology of the Soviet Union), who believed that the ideal way to true communism (essentially a post-scarcity utopia with no need for private property) was through the creation of an authoritarian one-party socialist state. They're also generally described as \"tankies,\" people who'd cheer the crushing of liberalizing dissenters like in Prague or Tiananmen Square."
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nr7bow | Why Do a Lot of Small Files Take Longer to Copy Then One Big One? | Technology | explainlikeimfive | {
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"It's like the difference between sending one envelope containing a 100-page manuscript vs. sending a hundred envelopes containing a page of the manuscript each. The resulting manuscript is the same size in each option, but with the second option the receiver has to spend time opening a hundred envelopes.",
"On disks, at the beginning of the filesystem there is a section that is used to store inode(index node) data structure. It's like an array, or, more accurately, an array of objects/struct. And each file has its own inode that tells the system things like file size, permission, and block number that the data of this file locates in. To copy a file, you will have to first find a free inode, write new metadata into it, then allocate new blocks somewhere else on the disk to store the actual data, write down the new block number into the inode, and then copy the data to the block that has just been allocated. Meanwhile, most modern filesystems have journaling function. Which means the system will need to log what the operation is and to what extent it has finished this instruction to make the system be able to recover from accidental power loss or crash. With that being said, for each file that you want to copy, there will be a short overhead time introduced. For a large file, you only need to do those extra steps once. But for an operation on thousands of small files with the same total size, you will need the same time plus thousands times of the overhead time. Therefore it will be significantly longer.",
"Each file copy has some overhead - you have to find the file, find a new location, move all the metadata, record the transaction information for crash resistance, and then actually move the data. These actions take time. They ruin memory locality - accessing non-sequential parts of disk and RAM - which breaks various optimizations the computer tries to make by pre-loading or reusing things. They can also take significant logic in addition to just the bare hardware actions of data copying."
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nr7x1c | expanding and compressing gases | To my understanding when a gas is rapidly expanding it cools and when it is rapidly compressed it heats up. So how come when you fill up a canister with helium/nitrogen/propane, etc. the canister is cold even though you’re compressing the gas into it? | Physics | explainlikeimfive | {
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"If you are using a compressor to fill the tank then the compressor will heat up and the tank become cool according to the differential in pressure between the compressors input pressure and the pressure inside the tank. If you are filling the tank from a larger tank, the same will occur with the nozel on the larger tank seeing the heating. Once equilibrium is reached, or you shut off the flow at the max pressure rating of the tank, the heating and cooling will cease also. If you think about it, a compressor is taking a large volume of air, and pressurising it down a pipe into a chamber where it expands. This has a max throughput of the max pressure inside the pipe from the compressor (otherwise the flow would be reversed from the tank back into the compressor). Once you realise where the compression and expansion might be, you can figure out what components will get hot, and which will cool.",
"If you're filling up from a big tank at a filling station, then the gas was already compressed. Compressing it into the big tank in the first place, using a pump or whatever, would have made the gas hot, but that probably happened hours or days ago and so the temperature of the big tank has equalized to its environment, so now it's compressed, cool gas. Now, when the gas from the full tank is released into your empty tank, it expands to fill it and suddenly becomes very cold. As the pressure inside your tank rises, the new gas entering the tank is doing less expanding, so the chilling effect is most dramatic at the start of the fill, and the tank should warm back up as its pressure rises. If you're filling up a compressed air tank using a pump, then it's different. The air starts out at room temperature and the pump will heat it up, and then it's *hot* compressed air being pumped into an empty tank, which expands and cools down but doesn't end up much colder than it started, so you won't see any frost or condensation on the tank in that case."
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nr80hp | With film photography, ISO was physically and chemically determined: big ISO = big grain, low ISO = fine grain. Why do digital sensors work with the same constraint? Why can’t we electronically have big ISO and fine grain at the same time? | Technology | explainlikeimfive | {
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"With electronic sensors, the effect isn't really grain size & mdash;obviously the sensor pixels don't vary in size & mdash; it's the amount of \"noise\" on each pixel. In other words, at high ISO, the brightness of each pixel varies randomly from what it should be. It's like listening to a faint audio signal; turning up the volume helps but you hear more hiss. With digital pixels the same thing is happening; turning up the ISO is like turning up the volume to make a weak signal stronger. The original signal always has some small amount of random error, but when you turn up the ISO by amplifying the signal more, you also amplify the errors which makes them more obvious in the resulting image.",
"They don’t, digital noise is only superficially similar to film grain but it’s actually quite different. Film grain is more like the size of the pixels which is constant for a given camera. When you turn up the ISO on a digital camera you are effectively turning up the amplification (think like a volume knob on a speaker), this makes the dark image you want to capture appear brighter, but it also makes any random noise (caused by thermal effects in the sensor, quantum effects etc) brighter as well."
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nr8rfe | How do we know what century it is , let alone year? | Other | explainlikeimfive | {
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"What year it is always depends on the calendar. The most popular being the Gregorian one. In the gregorian calendar, it is the 03/06/2021 today, but there are others, like the Aztec one or the Julian calendar. These are not measured things, like the age of the universe, where you can just calculate and always get an accurate measure, but based on an arbitrary point in time. For the Gregorian this would be the birth of Jesus. Since then we basically counted every year, so when the Gregorian calendar was established, other calendars showed that 1582 years had passed since Jesus Christs birth and that is where it continued counting. Since then there have been legitimate doubts about someone \"messing up\" and missing years here or there, especially since we don't even know for sure Jesus was a real person, but the calendar is well established and the benefit of changing the year, just to get a more accurate measure of the birth year of Jesus far outweighs the effort required to do so. So we don't exactly know what year it is, but it doesn't matter. We all have agreed on that it is the year 2021 and that is the important thing. Calendars are mostly used in the present, so you can tell people on which days you will meet up or when public holidays are.",
"We only “know” with reasonable certainty fir the last few thousand years, since we decided to start counting the days as they pass and passing that info on. As far as what the absolute date is relative to the beginning of the universe? We have only a vague guess."
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nr94oj | Why does the initialism LGBTQIA+ keep expanding? Doesn't the "+" already count for everything not included? | Other | explainlikeimfive | {
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"LGBTQ+ has been pretty popular since at least the start of the 00s, as far as I remember, and to my knowledge \"IA\" has become a popular inclusion in the past 5-10 years or so. I'm not sure that \"Keeps expanding\" is the right way to describe it. You're correct that the '+' is basically meant to mean '...and everyone else we forgot to list', but sometimes activist people and organizations want to communicate in a way which puts specific spotlights on specific groups of people and their issues and struggles. There isn't really an 'official' initialism, there's no central organization that says \"OK, we're adopting the 'IA' this year!\" and not everyone in this community (if we can call it one) is on the same page about which letters should be included and why, in which use cases. I've also seen some other letters included in some versions, such as \"2S\" for 'two-spirit', which is an aboriginal gender concept. There are some publications which leave out the Q. Still others include a second Q for 'questioning.' LGBTQIA+ seems to be a standard which a lot of people in Internet communities have informally agreed upon, but it's it's hardly a *real* standard.",
"LGBT is sufficiently inclusive in most cases. If you want to include other related communities such as intersex, asexual, or allies you could use LGBT+. There is no official standard for this and the variant used is mostly a matter of personal choice."
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nr9eaj | Recording years before Christ. | Other | explainlikeimfive | {
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"It varies across cultures. Even today for example Japan marks years as X year of the reign of emperor Y. Most Islamic countries count from year 1 being the year of the Hirja. For the cultures you mentioned ancient Persians/Iranians usually used x year of King ys name which seems to be the most common across cultures and Greeks counted it based on Olympic games eg third year since the twelfth Olympics.",
"The most common technique was to count years from when their ruler came to power. So similar to how you would specify that you are counting years since the birth of Christ today you would have to specify which ruler were in power at the year. This was how we counted years since at least around year 5000 BCE. This did work well when you had huge empires which a single ruler or smaller kingdoms who rarely communicated. However after the Roman Empire we got a civilization in Europe which consisted of lots of small kingdoms who had a lot of trade and communications between them. And this is when our current system of counting years were invented.",
"Hebrews counted “from the creation of the world”, and Hebrew calendar still does. Ancient Egyptians, over 3000 years had many calendars but typically counted years in the reign of a pharaoh. Rome counted years “ab urbe condita” or from the founding of Rome. Mind you, Western Europe didn’t widely start counting “form the birth of Christ” until the 9the century.",
"Some cultures counted using dynastic time: the 3rd year of king's smith's ruling, sone of John sone of Bob son of Herbert the great etc. Others used a certain event, eg the jews count from the creation of the world (now its the year 5782).",
"Most Calendars of antiquity reset every time a ruler came into power. So it would be something like \"The tenth year of the reign of King John\" or the like. Every kingdom/empire would have a different calendar. Some calendars were of a little wider scope and counted from either the establishment of the kingdom/city state (such as the founding of Rome) or from the creation myth of that given society (such as the Jewish Calendar)."
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nr9inn | If a thundercloud contains over 1 million tons of water before it falls, how does this sheer amount of weight remain suspended in the air, seemingly defying gravity? | Physics | explainlikeimfive | {
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"At the scale of cloud droplets viscosity is a force vastly superior to gravity. Gravity is applied to mass, viscosity* is applied to surface area, and smaller things have more surface than they have mass. Imagine you drop a stone into water - it will sink to the bottom right away. Now if you grind this stone into sand and let this sand fall into water it wouldn’t sink right away, despite being the same mass. It will take its time, and if you stir this sand just a little, it will make a swirling sand cloud in the water which can persist for a few minutes - precisely because sand particles have much more surface area than the original stone while having the same mass. The same thing happens with water droplets in the cloud. Very small water droplets just float on the upward air currents (note that thunderclouds form when there are strong upward currents to begin with). When this droplets become bigger by joining each other (reducing their overall surface area) they start falling to the ground making rain. Edit: *viscous friction actually.",
"Imagine a plastic bag in a huge desert. If it's windy, it floats in the air. But that's obvious because a plastic bag is light enough... Now... imagine a LOT of plastic bags. Like a million tons of it. Thats a lot... If you were to crumple them into a big ball, no wind would move that. It weights a million ton. However... if you DON'T crumple them together, and they can flow individually in the desert, they just float individually in the wind. A cloud is (superficially) similar to that... This is an OVERsimplification of the science, but I think it is simple enough for a 5 year old :D",
"Floating has nothing to do with weight. It's all about density. 1 million tons of water vaper, which is less dense then air, will float. A single drop of water, which is more dense then air, will fall.",
"Imagine a small cat. (Trust me this is going to be relevant). That is about the size that creature needs to be and of the weight that things like viscosity of air starts to actually matter to it, more than gravity (on our planet). Imagine swatting some ants off a table and you see them fall on the ground barely even noticed the fall. You see them walk on surfaces without a care about what is up or down. This is because at that size forces like viscosity and surface tension become more relevant to their experience. For example fairy fly experiences flying through air like swimming in oil or such. Now when a cloud forms up in the sky, the droplets of water in there aren't heavy enough to really \"feel gravity\" against the mass of air that they are suspended in. Don't take me wrong they are still subjected to it the same way every thing including the mass of air is. It is incorrect to consider cloud as one object, it isn't. Each droplet should be considered as individual. The thundercloud is not million tons of water in the air. It is million tons of water in form of small droplets. Because water like to stick to it each other once the droplets combine they become big enough that air can't support their weight and gravity takes over, and they fall as rain.",
"Air has weight as well, and if you have two boxes of equal size and fill one with air, and the other with water vapor, the box with the water is going to weigh less than the air. This is because water vapor has a lower density than air. There is \"more\" air than water vapor in any given volume. And because of this water vapor rises, its sort of like if you had a balloon under water, the balloon has a lower density than the water, so it floats. Water vapor has lower density than liquid water, and lower than air. So water vapor \"floats\".",
"All the discussions about suspension of water in air and resistance to falling because small particles are slow to fall, and all that, are part of the story. The real, or most important, reason is that the amount of volume that holds such a large mass of liquid water is enormous, so even though the amount of water in unit volume is actually quite low even in thunderstorm clouds (several grams per cubic meter as a general idea is a pretty good estimate of water content in thunderstorm clouds), when there is a huge volume involved, the masses get huge too. Most of the cloud is not water but thunderstorms are huge: many kilometers high and covering many tens of square km of horizontal area. this means that the thunderstorm is on the order of maybe 100 cubic km in volume (10 square km area by 10 km high=100 cubic km) or a lot more perhaps. Well, 1 cubic kilometer is 1 BILLION (thousand million) cubic meters, so a single cubic kilometer of cloud would have about 5 billion grams of water, or five million kg, or 5,000 tonnes (metric tonne is 2250 pounds, about). Expand that to include all of that 100 cubic km cloud we just mentioned above, and the total amount of liquid water would be 100x5000 tons, or 500,000 tons. Make the storm a bit bigger or the water content a bit higher, and you get to 1 million tonnes. It is a lot of water, definitely, but the volume is really big. So the \"real\" reason is simply that thunderstorms are really big so there is a lot of water in total. The real fun thing is that the weight of the air in that same volume is way higher than that million tonnes of water. Air is on the order of 1kg per cubic meter (depending on how high you are; about 1.2 kg per cubic meter down here at earth surface). You didn't ask why the air doesn't fall even though it has way more mass.",
"It also depends on the cloud. A typical thundercloud is about 15 miles in diameter and thousands of feet high. To put it in perspective, the biggest swimming poolin the world is in Chile. It’s 11 feet deep and 1,000 yards long that holds 66 million gallons or about 2 million tons of water.",
"It's not a matter of gravity because it's not water dropplets floating in the air. It's water making up part of the air. Think of air like a sponge that can hold water. The colder the air is the more you're squeezing the sponge and the water that was previously part of the sponge needs to go somewhere else At 40°C one cubic meter of air can hold 51.1 gramms of water. At 25°C it's less than half ... 23 gramms. So that million tons of water that's a trillion grams which needs about 20 billion cubic meters. That sounds like A LOT. But let's say a cloud is as high as the One World Trade Center (~500 meters) were down to an area of 40 million square meters or 40 square kilometers. That's only about 2/3rd of Manhattan Island. And all it takes for half of that to fall down is a \"squeeze\" like going from a really hot to a moderately warm day."
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nrbg6q | Is there a way to completely stop excretion*? Like a certain diet a person can follow exactly that would completely eliminate excretion? | *not including excreting carbon dioxide | Biology | explainlikeimfive | {
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"No, excretion is waste. The body is not 100% efficient. So no matter what the diet, there will always be waste.",
"No. A lot of the toxic byproducts of natural metabolic processes (like cleaning up malformed proteins) must be excreted. This would occur even if your diet was made entirely of fully absorbable matter.",
"Short answer: No. Human bodies create waste products in their functioning so even if you were to have an IV of exactly the correct level of nutrients and liquid, you would need to get rid of those waste products. (I am a bit concerned for your well-being. I understand that being a body piloted by a brain can sometimes be unpleasant but, if this is more than idle curiosity, please consider a mental health professional who can help you be more comfortable with how your body supports you.)",
"While 'No' is the simple answer, it's definitely possible to reduce it significantly. You could probably get it down to 2-3 weeks between each one."
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nrco3l | Why do high calorie foods like table sugar, honey, chocolate, jams and spreads have such a long shelf life instead of teeming with bacteria after a few days? | Biology | explainlikeimfive | {
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"Sugar, honey, and jams have such a high concentration of sugar that they will pull water out of any bacterial/fungal cells that land on them, as sugar is hygroscopic (it sucks water out of whatever is around it). The cells, without water, cannot survive, so they will die. Over enough time and with enough water, the sugar will not longer be able to pull that much water out of the bacterial cells, meaning they can survive and reproduce. So the food must have a very high concentration of sugar in order to last; lower concentrations will go bad much more quickly.",
"Not all high calorie foods are created equal. Your example of table sugar, honey, chocolate, jams, and spreads are all high sugar (or basically all sugar) items. Sugar is hygroscopic which means that it absorbs water from its environment which includes bacteria. Bacteria cannot survive without moisture and basically collapse when it is removed (similar to how salt is a food preservative). So the things you listed basically do not allow the growth of bacteria because they absorb the moisture required for bacteria to grow and live."
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nrcyvb | If everything in the universe want to go from unstable state to more stable one, than why destruction is more easier than building? | Other | explainlikeimfive | {
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"Because a pile of rubble is a much more stable state of things then a standing building. Push a building hard enough and it collapses into rubble - unstable. Push a pile of rubble and it remains a pile of rubble - stable. So the universe wants the building (unstable) to become a pile of rubble (stable), therefore destruction is simple - the universe is helping you. Not so the other way round.",
"Your definition of stable is off here. The universe strives towards equilibrium but to us it looks like chaos. When you open your windows on a cold day it's not really the warm air leaving as much as the inside temperature and the outside temperature trying to even out (with much more cold air outside than warm air inside it obviously tilts towards cold in this scenario) So you can view it as chaos insofar as the order we created (warm boxed up air) is destroyed but on a universal scale your little hotbox is not order at all. So if the universe is a beach and you build a sand castle then that sand castle is the irregularity - the unstability - and not the order. Order would be a perfectly even sand bed. I made all of that up.",
"Define \"stable\" and \"unstable\". Everything in the universe is ultimately following the fundamental laws of thermodynamics. What physicists means when they say \"stable\" depends entirely on context. \"Stable\" in the context of the universe probably means: Maximum entropy at minimum temperature. It's always easier to increase entropy (i.e. destroy) than to decrease entropy (i.e. build). In fact, decreasing entropy is physically impossible. Humans are little entropy machines. We take matter and break it down. All we ever do is increase entropy (i.e. create chaos from your perspective but actually increasing order from a universal perspective).",
"You're confusing \"stable\" with \"organised\". The two are mostly the opposite - disorganised states are mostly more stable than organised ones. The universe tends towards disorder. 5 kiddy blocks in a stack are very ordered, but hugely unstable. Build a stack near a young child and see how long the structure lasts (answer - about 2 seconds, because one nudge, of just about any sort, and they all go flying - and kids just LOVE giving them that nudge). Now look at the same 5 blocks after they've been knocked over. They're spread all over the floor, and that's unlikely to change, however much the child randomly knocks them about. They're disordered, but they're very stable.",
"Interesting question, thank you. A couple examples that satisfy both conditions to some degree is the WWII Wolf's Lair and anti-aircraft towers. Similar to another person's response they could be thought of as giant piles of rubble that when hit with bombs would more or less remain a similar giant pile of rubble. The difference here of course is that they would still be usable."
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nrdcrg | If all lifeforms on earth are carbon and water based why is there such a difference in colour, texture and form? could theoretical life forms based on other elements have a similarly broad variety? | Chemistry | explainlikeimfive | {
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"The whole reason that carbon makes a really good basis for the formation of complex life is because of the huge variety of compounds that carbon can form. Carbon is an incredibly versatile element that can form everything from diamond (the hardest substance known) on down, and at reasonable temperatures you can find carbon compounds that are solid, liquid or gas, making exchange of nutrients with the outside world much easier. It would actually be something of a surprise if there \\*wasn't\\* such a wide variety of life given such an amazing starting material. Trouble is, there's very little else in the periodic table that has the same properties. Silicon can form long-chain compounds in the same way carbon can, but only when combined with oxygen, and even then it's not anywhere near as versatile, so if silicon based life existed it might not have the same variety. As for anything else, it just doesn't work--any life based on something other than carbon or silicon would have to be so utterly alien that we haven't even thought of how it might work."
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nrdmge | Are deep voices related to how long and thick vocal chords are? | Other | explainlikeimfive | {
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"Your vocal folds are really two thin membranes sitting on top of your airway, at the top of your larynx, sitting ready to meet in the middle and close it off. When your airway is \"open,\" the two membranes sit apart from each other like the two sides of a V, where if you look down at it, you're looking down between the sides of the V into your open airway. The membranes are always together at the bottom, but there are tiny muscles and cartilages at the tops of the V that pull the V closed into an I to close off your airway. Your \"voice\" works when you pit [the muscles closing your airway off] against [the muscles of your lungs pushing air up from underneath them]. The air pressure blows the membranes apart briefly, but the larynx muscles make sure they snap right back together. This, repeated over and over, creates sound. That sound resonates in your entire head and neck, basically \"playing\" your head like an instrument. The sound that goes out into the air is what other people hear as your voice. Now to directly answer your question: The more mass something has, the slower it will move relative to something with less mass, given the same amount of force. So, yes, the longer (or thicker - see*) the sides of that V are, the slower they will vibrate, and the lower the frequency. But also, it has to do with the way the head and neck are built, since these are the resonators that determine how those vibrations are going to come out sounding. *Thicker - this is why your voice sounds lower when your larynx is inflamed. The two membranes get swollen, i.e. thicker and bigger (just not longer), and so they move more slowly/ can't do their thing at as fast a frequency. Interestingly, when people (such as myself and many friends of mine) go on testosterone for gender reasons and their voices drop permanently, their vocal folds don't get much longer, but they do get significantly thicker, hence a lower voice but no Adam's apple, and hence why we generally become tenors and not baritones or basses (which would require much longer vocal folds). Source: master's in speech language pathology",
"Length and tension. Then you decide how much air vibrates through them that creates s unique voice.",
"Vocals cords are misnamed, they are really folds, so don’t think of them like harp strings. Pitch depends on how fast they can vibrate"
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nredvu | What is the noise some cars make when reversing? | I always wondered why it sounds different from a “normal” forward drive. | Technology | explainlikeimfive | {
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"Most forward driven gears are helical, so they mesh together on an angle. They're more expensive to produce and require synchronizers, but they are quieter. Usually reverse gear is a straight cut (spur) gear, which is much cheaper to produce and doesn't require a synchronizer. The trade off is they are much nosier and produce that whining sound. [Helical vs Spur gear]( URL_0 )"
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nrejka | What peer-reviewed science is? | I've been looking at some series that are based on peer-reviewed science like "Missing Links" by Gregg Braden, and I've been reading that recent studies use peer-reviewed science, but it's not clear to me what it really is. If someone could ELI5, I would appreciate it. | Other | explainlikeimfive | {
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"Peer review is the process of having your work reviewed by others in your field before it is published. The idea is that if you write a scientific paper and it isn't total bullshit a team of reviewers who are also experts in your field should be able to review it and say \"Yeah this is proper science and makes sense\" and then they pass it on to the journal and say \"We think this is good enough to be published\"",
"Peer-reviewed means one group of researchers did the experiment and recorded all the information about it (why they did the experiment, how they did it, what the results are, and how they interpret the results), and then *another* group of researchers reviewed all that to determine whether or not it was actually done *right*. Like, if a group of doctors did a study about amputating nipples, other doctors or a panel would review that study to decide whether the study followed all the rules for medical studies that were established by the international association of doctor folk. It makes the study more legitimate/valid. It is the difference between me doing some random crap in my basement and then saying, \"Hey look at my findings here, this will change the world!\" and a researcher applying the right methods to do an experiment to ensure everything was done right."
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nrewqy | Why can't we truly multitask? Why is our "multitasking" just setting something aside real quick to do something else? Why can't our limbs perform different tasks at once? | Biology | explainlikeimfive | {
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"Basically, our brains can only pay active conscious attention to one thing at a time, called our \"locus of attention\". As far as we can tell, this is an architectural limit of our brains. It's like asking why we can't play three-handed piano pieces by ourselves...we only have two hands. Multitasking in the sense you mean requires more than one locus of attention and we've only got one. As a result, the only way we can approximate multitasking is to task-switch quickly...which is actually terribly inefficient and a bad way to work but sometimes we don't have a choice. We can have our limbs do different things at once, but only one of them can be something requiring conscious attention. That is, for example, how we can steer our car while sipping coffee or march while playing an instrument. The other function(s) need to be something we've trained enough that we can do it autonomously.",
"Each area of your brain can only do one thing at a time; you simply don't have any spare brain matter to devote to doing two or more similar tasks (which is not something like talking and walking, which are two different tasks in two different parts of the brain). In an average person, the parts of your brain that control your limbs (one for each limb) could theoretically multitask, except they're also busy coordinating with each other and with other parts of your brain. There are people who are split-brained, who've had a surgical procedure done that splits the connection between your right and left halves of your brain (usually done to stop seizures). In those cases, they sort of can multitask, with each side of their body able to act independently of the other. However, it's more like they're two individual people sharing a body rather than one person able to do two things, as their limbs can now start disagreeing with each other.",
"There are other good answers about the mechanics, but some evolutionary perspective is needed to explain the larger \"why\". There are two good reasons. One is that multitasking, as we think of it, is possible thanks to the technology we have that has only existed a few decades or centuries, depending on what tech you mean. Our ancestors could not have multitasked with a computer, phone, car, or even a pencil.. not even if they wanted to. Number two: it's not a bug, it's a feature. The distinctly human part of us that does \"attention\" to one thing has some pretty amazing capabilities. We can do reasoning and analysis. We can entertain counterfactuals (imagination of \"what if..\"'s). We can solve puzzles, investigate questions, and in the process integrate information learned from others, from our senses, from our own imaginations, or from our previous experiences. While some animals can produce novel solutions and make tools (corvids, cappuchins, apes), no animal comes anywhere near to the cognitive prowess a human possesses to process and solve a totally novel problem or question. But it's not free. It involves the coordinated, integrated effort of many cognitive functions all at once. In a sense, we are multitasking. Consider, for example, someone comes to a gate they must open that they've never seen before. Perhaps one of those side gates at a friend's house. Usually, a person will look at the gate and mechanism, jiggle and move bits and open it without issue in a few seconds.. even if they've never seen the design before. This seems very simple, but consider all the things that have happened in those seconds: the visual scene must be accurately perceived, objects recognized. Knowledge from memory is accessed to provide crucial contextual information: this device is an entry point that can be opened and closed. If a latch of some sort is visible, the person quickly reasons in their imagination space about how a bolt must be manipulated to permit motion of the door. If a latch is not visible, they reason such a device must be present perhaps on the other side and further consider its likely location. Whatever the case, they attempt to physically manipulate the latch while simultaneously monitoring the door for free movement. I've listed these things in a sequence, but really most or all of them would be happening simultaneously, dynamically. It's pretty amazing really.",
"> Why can't we truly multitask? Why is our \"multitasking\" just setting something aside real quick to do something else? Why can't our limbs perform different tasks at once? Your question is based on a false premise. We CAN truly multitask and we do it all the time. We drive and listen to the radio, we walk and chew gum, we stand and read signs. We could not navigate life if we could not truly multi-task."
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nrf32b | why helium or normal balloons eventually deflate? | As the title says, can someone explain why both normal latex and helium balloons eventually deflate? Does the air/helium escape very slowly somehow? | Physics | explainlikeimfive | {
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"Rubber isn't perfectly airtight, so the molecules of the air inside do eventually escape causing the balloon to deflate. Since helium is more stable and smaller it escapes faster than other balloons."
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nrgy1v | Why do rear end collisions cause so many injuries but 11,000 horsepower dragsters accelerating from a standstill cause no damage to the driver? | Physics | explainlikeimfive | {
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"A dragster still accelerates at a relatively steady rate...it's \\~4g average for a top fuel dragster, less than a typical rocket launch. The \\*steadiness\\* is key, as is the fact that the driver is ready for it and thoroughly strapped into a seat designed for it with a harness designed for it and their head against the headrest. There's very little motion of the body. In a rear-end collision the acceleration can be much higher, on the order of 16g, because it's such a sudden impact, and your head generally isn't constrained...at the time of impact, it's free in space because we don't usually drive with our heads back against the headrest.",
"A top fuel dragster driver has an uncomfortably tight five point racing harness, HANS restraint, helmet, fire suit, and conforming racing seat. They’re focused on the tree waiting to launch. A Honda Civic driver has a loose three point harness and is looking at their cell phone. There’s a lot of whiplash that can occur when the car suddenly launches forward unexpectedly and your head isn’t supported.",
"Collisions cause a sudden change of speed, meaning that there is a short-term but extremely high acceleration (acceleration is change of speed divided by the time in which that change takes place). However high an acceleration a dragster achieves it still falls short of the collision acceleration by a long shot.",
"In addition to the other good information here, keep in mind that drag racing is hard on the driver's body. The g forces they experience -both accelerating and decelerating - take a toll. When the parachute deploys, they slow down so quickly that it can lead to retinal detachment over time."
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nri6wp | What is the Concept of Absolute Hot? | If absolute zero is when no more heat can possibly be removed from an object, and the particles are at a complete standstill, what is the contrary to it? | Physics | explainlikeimfive | {
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"Light is made of photons that are pure energy and when those photons hit something, heat may be generated. These photons have a wavelength. As the energy of the photon goes up, the wavelength of the photon gets shorter and shorter and the energy transferred in the form of heat higher and higher. Eventually, at around 142 Nonillion degrees *Celsius*, the wavelength is so short that it reaches the plank length, the shortest possible distance of known physics. The energy of these photons are so high, that if it was converted directly to mass (E=mc^2 ) then it would create a black hole. After this point, if it is possible to increase the energy of the photon even further, no one knows what would happen as all the known laws of physics break down. So, they just call that point the \"Absolute Hot\" as that much energy would have to be put into a photon to theoretically create that much heat from it. Edit: degrees Celsius"
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nririt | How did they know how many days were a year in the past? | I know that the seasons were indicators but how did they know precisely to the day how much a year was. Edit: Copying from a response I made: "Thanks for the response! But I still have a doubt cause most of the reponses are to measure it in certain way and wait until the sun goes back to its initial position, and I get how measuring its easy by doing it over a long period of time but the difference between 2 days seems kind of difficult to notice, like when the sun got back to its position and people were like "yeah it looks about the same as how it started" and then they observed the next day and it looked exactly the same, how did they decide a specific day. I guess my question is more about how they achieved such precission rather than the method" | Earth Science | explainlikeimfive | {
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"So actually **not** by measuring the sun. The Egyptians were the first to figure out that there were 365 days in a year. Before that calendars usually had 360 days because it more or less lined up with everything and the Babylonians used a base 60 number system that this fit well in. It’s also part of the reason we have 360 degrees in a circle. This was more based on observing the moon too. You’d have a new moon cycle roughly every 30 days, and 12 moon cycles would more or less line up with the sun being in sorta the same place and the seasons coming back around. Eventually this would fall out of sync since the moons cycle isn’t actually 30 days, and there’s not 360 days in a year. So sometimes they’d add an extra month here or there and it worked well enough. But the Egyptians looked at the stars instead. They saw that the star Sirius appeared just above the horizon at dawn at the same time every 365 days. That lined up closely with the flooding of the Nile too, so it was significant beyond just being interesting. It gave them greater predictive power over important events. So they made a calendar with 12 lunar months, and then 5 extra days on top of that for 365 days total. They did know it came a day later every 4 years, but they just let that slide. The calendar fell behind a little bit every four years, but they could see by looking at Sirius when it had been a year and the Nile would flood again. They put a lot of emphasis on observing the stars for largely religious reasons. So they could see pretty clearly when an important star appeared to rise in the same location. It’s more of a discrete event to them that they could see happened every 365 days than a measurement they had to try and get right with tools from 5000 years ago.",
"Set up a couple of rocks aligned with the Sun's position on the horizon at sunrise. Keep a tally of days as you observe the rising Sun change its position north and south and north again until it's back in the original position. Keep that up for several years; after four years, 1461 days should have passed. Keep it up longer for more precision.",
"They would count the days. They would have something that would help them tell the changes in the sun's position over time. They counted the number of days it took to for the sun to return to the same position. URL_0 Here is an example, they would count the number of days It took for the sun to reach the maximum or the minimum and back again"
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nrk52a | what does sexual frustration feel like? | Other | explainlikeimfive | {
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"Like having to poop extremely bad but having a football sized bowel obstruction except it’s happening in your **crotch**"
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nrldt5 | why a deer freezes in the headlights? | Biology | explainlikeimfive | {
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"It’s the fight or flight instinct. They just get caught up in figuring out which one they want to do.",
"Deer are evolved to deal with predators, not cars. When they spot a car it is quite far away for a predator and so holding still to hide would tend to be effective. So they are standing there trying to figure out what they are looking at, if it is a threat and even seen them, when suddenly it has barreled down on them faster than any predator they have adapted to. Also keep in mind that automobiles don't show movement like animals do. If a wolf is sprinting at you the legs will be pounding, the shoulders and hind quarters bobbing, in general looking very different to if it is just standing there. In contrast deer likely have plenty of time to observe automobiles at night when deer are out feeding. Parked automobiles that is; they spend hours on end without moving at all. When they move though it is faster than any ground animal and the spinning of wheels is minor and doesn't change their silhouette. Headlights and other signal lights are similarly unexpected by deer as no animal emits such things. So a deer might think something like this: \"Is that a quiet growl in the distance? Freeze, what could it be? Weird, is that a pond reflecting the moon over there? It is way off by one of those boxy rock things, maybe the growling is from behind it? Well it is a long way off so... no wait, it is right up on me now?! Ahhh!!\" Bonk!"
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nrli65 | How does the science behind using your left and right hand on the piano at the same time work? | Biology | explainlikeimfive | {
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"Its called training. Your brain can easily controll all of your extremities in parallel for different tasks. When you eat you also make different movements with both hands. When you type the same. Once your brain figures it out its a no brainer. Like driving a car where you use one or both feet, and both hands for different tasks. If you drive manually each limb has its own job ( clutch, gas/break, gearshit, stearing)",
"I'm a life-long pianist who plays by ear. This is a mixture of things. First, it's \"muscle memory.\" You don't play piano by actively thinking about everything your hands are doing, you do it by \"feel.\" Think about it in the same way you drive a car around a corner at an intersection. To do this successfully you need your feet, your hands, your eyes, and your head to work in concert with one another. When you were learning to drive, this was likely a very difficult task. As time went on, though, you began to do it automatically, without thinking. You flick the turn signal stalk up to indicate a right turn. The foot slowly applies just the right brake pressure to slow the car down comfortably as your head and eyes swivel to check for cross traffic. Looking ahead into the corner, you turn the wheel as you let off the brake to just the correct angle to make it around the corner without crossing into incoming traffic or hitting a curb. As you round the corner you straighten up the wheel, center your gaze, and hit the gas pedal to accelerate out of the corner. This is all an amazing feat of coordination that a lot of people don't realize they do every single day. The human brain is truly remarkable. That's what it feels like to play piano at that skill level. You don't think about it; you *feel* it. It flows out of you naturally and effortlessly, like you're not even controlling it. It's honestly a great feeling and is one of the most relaxing things I do for myself. I just plug in the headphones and go.",
"Cerebellum will remember movement patterns. A lot of music is just patterns so if you practice it a lot your brain can just remember what to do for both hands"
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nrlzph | how does compound interest work. | Economics | explainlikeimfive | {
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"Compound interest means that the interest is added to the balance, and next period's interest is calculated off of the total balance, including the interest. Hence, it compounds. $100 gaining 10% interest, compounding annually, grows like this: End of year 1 - 10% of $100 which is $10, total balance is $110. End of year 2 - 10% of $110 which is $11, total balance is $121. End of year 3 - 10% of $121 which is $12.12, total balance is $133.12. End of year 4 - 10% of $133.12 which is $13.31, total balance is $146.43 You see how each year the amount of interest goes up? It's compounding - you're getting interest on the interest.",
"ELI3: Let me hold some money for a while and you will get extra, then later extra **of the extra too**! ELI5: Simple interest = a bit of what you gave me. Compound interest = a bit of what you gave me and a bit of that bit. For example: Let's use 10% a month interest. Let me hold your $10 (so I can use it) and a month later if you want it back I'll give you $11. If I get to hold it another month it'll go up not by $1 to $12 but by even more! If you want it back then you can get $12.10. After 1 year you'll have $31.38. The magic really increases over time, so that in 10 years you'll have **$927,090.69**!"
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nrm36b | how can you sing in a tonal language? | Other | explainlikeimfive | {
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"For Chinese (both Mandarin and Cantonese), the context of the words being spoken reduces the reliance on tonality. Sure, you might be saying that you loved your \"horse\", but in a song about your parents, it probably meant \"mother\" (both are pronounced \"ma\" with different tones). Meanwhile, a song about Genghis Khan is probably centered more around horsemanship than motherhood."
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nrmjiy | why do downloads occur at faster rates along the download process? | Technology | explainlikeimfive | {
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"text": [
"Downloads are done over the TCP protocol, and TCP gradually ramps up the speed until it finds how fast things can go. When you're downloading something you're constantly sending confirmations of \"yeah, I got this bit\" to the source, and the source throttles things down if confirmations stop arriving in a timely manner. Things also start quiet and gradually ramp up, until the system finds the maximum speed that works."
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nrmtcn | How did countries like Hungary manage to fix their hyperinflation while Venezuela is still dealing with it after 10 years eventhough Hungary had it was worse in terms of inflation? | Economics | explainlikeimfive | {
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"Hungary solved its crisis by abandoning the Pengo (old currency) in favor of the forint (new currency). They basically started over. The conversion rate was like 1 forint for every 400,000 quadrillion Pengo. This is obviously not an easy thing to do, and Venesuala has held out hope so far that it won't be neccessary.",
"Hungary basically cheated their creditors. They printed money to reboot their industry and left their workers working for poverty wages. They then bailed on their creditors and left them empty handed. With no debts to pay, Hungary survived. It was producing, but workers were poor, and creditors were SOL. Lucky for Hungary, they were taken over by communist Russia which started the economy over from scratch, Communist style. We don't know what would have happened if the Communists hadn't taken over. It could have turned into something like Venezuela.",
"It’s also important to understand what gives currency its value. Modern currencies aren’t backed by gold, they’re backed by products a society manufactures, labor or resources. These have to be products/resources people are willing to work really hard for. Currency is always thought of & confused with actual resources, but currency itself is NOT a resource. People don’t work for currency, they work for what the economy produces, & use currency as the tool to facilitate their trade of these resources & products. You can recognize believers in this myth in people who say we can solve this or that problem in society just by putting more money towards it; failing to realize, just because you threw more money at it doesn’t mean you increased the actual resources required to fix the problems. With Venezuela, they are a 1 trick pony, they do oil. So when that 1 resource collapsed they thought they’d throw money at people to keep the economy going. Except their currency was backed only by oil, so when oil lost its value, so did the currency, no matter how much they printed. For Venezuela their only solution is for oil to go up really high, or for them to diversify into new products that people are willing to work to buy. Right now oil is only going up with general workdwide inflation. They need oil to go much higher. Hungary on the other hand was a manufacturing bastion. Hungary always had a more diversified economy from the start."
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nrmyal | How does it work when you mentally block out pain? What happens in the brain? | Biology | explainlikeimfive | {
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"Say you prick your finger with a needle. Damaged cells in that area release chemicals that cause tiny nerves in the area to fire. These signals make their way from your finger to your spinal cord, where they then travel up the spinal cord and into your brain, which creates the sensation of pain. But--it's not a one-way signal!. There's a second pathway, called the descending inhibitory pathway, that gets input from a bunch of different parts of your brain and actually sends signals through a second set of nerves all the way back down the spinal cord and out to the fingertip. That second signal does a few things--first, it actually can block the first pain signal at the spinal cord level. It also can act at the nerve endings that first felt the pain, making them less sensitive. That descending pathway communicates using endorphins, which are very chemically similar to opioids like morphine, heroin, codeine, etc. That's why these drugs are such effective painkillers!"
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nrnl41 | How do plastics stretch? | Physics | explainlikeimfive | {
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"Simple question, complex answer. I guess the shortest answer that is most-est right would be: Plastic is made up of long chains of molecules, all tangled together. When you pull on it they start lining up. Enough stay cross-linked to keep it in a sheet, but otherwise it stretches out (and gets a bit thinner). Think of it like a plate of spaghetti, look at what happens when you grab a couple of forks and 'stretch' the pile. Same thing\\`s happening in that plastic. The complex bit - not all plastics are stretchy, some only stretch in one direction, some stretch only when warm... it gets pretty technical. I hope I\\`ve answered your question about that one type of plastic."
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nrno7f | What determines your alcohol tolerance? | I mean, I know weight and height are a thing, but what variables make metabolizing alcohol more or less effective? Why does a person get drunk with a beer while a similar one in weight and height can drink no problem? | Biology | explainlikeimfive | {
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"Experience, stomach contents, consumption rate, and body composition. Experience - The more you drink (and the more frequently) the \"higher\" tolerance your body will have. Basically it starts to adapt to increasing levels of alcohol. Stomach contents - If you have food in your stomach that is able to absorb some of the alcohol, it will slow how fast the alcohol is entering your system. Say you eat a chunk of dry bread. It will get wet with saliva from your mouth, but nowhere near saturated. So once it enters your stomach it will absorb some of the liquid there. This means your body has to break down that bread for the alcohol to come out. This won't keep you from getting as drunk, it just slows down the rate you get there some. It definitely won't sober you up. It doesn't remove any of the alcohol in your blood, it just slightly slows the rate new alcohol enters. Consumption rate - literally how much alcohol you are consuming in a given time frame. Beer is usually 4-8% ABV. Lots of liquors are 40% ABV. So if you take 3 ounce and a half shots, you may have consumed less liquid volume than a single beer, but you consumed a hell of a lot more alcohol, and you did it very quickly. Body composition - Alcohol is more soluble in water than fat. Muscle contains more water than fat does. So a person with more muscle (even if similar height and weight) will tolerate alcohol better. Not a scientific article, but a decent break down: URL_0",
"Doctor here, and back when I was working the ER of a notoriously hard partying college town Thursday through Sunday was prime time for alcohol related overdoses. The short answer here is that there are far too many variables to list. Body mass, experience, liver function and method of delivery are the big ones but all the rest like hereditary, medications, certain comorbidities, etc can also add up to tip the scale as well. This is generally true for any intoxicant even tightly regulated/titratable pharmaceuticals administered by a healthcare professional."
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nrq29a | how some sea creatures live in the deepest place of the sea without being crushed under all that water pressure? | Biology | explainlikeimfive | {
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"Water, like many fluids, are (practically) incompressible. So as long as they are filled with fluid, they can't be crushed by water pressure. It's tough for humans to go that deep because our lungs are filled with air, which is very compressible by comparison. In fact, there's a [theory]( URL_0 ) that maybe we could breathe an oxygen-rich liquid at depth, but it has not been achieved practically.",
"Ever see a blob fish? They don't look like that while they're in their natural habitat. The lack of pressure makes them look like blobs.",
"I'm sure you will get better answers than this but I'm going to draw your attention to the Blobfish. Unlike most of the fish we eat, it has no air bladders that allow other fish to control depth and navigation, and most of its body is gelatinous, which means its tissues are comprised largely of the water that surrounds it. In its natural habitat, 60 atmospheres or more, it has a very different appearance then it does at the surface. As its natural depth it looks more like a typical fish, but when brought to the surface it more or less explodes and takes on the blobby appearance that we named it for. Couple of things in play: pressure from the volume of water outside an animal at a great depth, and pressure from the volume of air/gas inside an animal. Water is not very compressible. Gas is very compressible. And I want to point out that there's a shitload we don't know. Because as smart as people think they are, we have only been capable of analyzing this planet in any detail for less than a hundred years, and the deep ocean for much less. Decompression sickness, or the bends, occurs in humans because pockets of gases in our lungs and bloodstream get smaller under compression at depth, and then expand when we rise to the surface. If we rise too fast, the gases can expand at a rate greater than the surrounding organs can accommodate. It's interesting to note that deep-diving whales actually stop to decompress like deep divers do. In both cases, this allows the gas pockets to size themselves and redistribute themselves in a way that avoids blocking pathways in our gas carrying systems ( which we call embolisms). Deep living ocean organisms tend to lack gas carrying organs (air bladders) so that gives them a greater range of depth to mess around in. Animals that live closer to the surface have these air bladders which they use to navigate up and down. But wait, there's more. Deep living ocean organisms, as far as we have observed, have cellular adaptations, sort of really thick cell walls, that are specialized to help them withstand the water pressure at great depths. But these adaptations don't help them when we bring them from the great depths to the surface. This could be (likely is) because they still do need gaseous oxygen in their tissues, and the decompression of that gas causes a rapid expansion all the oxygen bearing tissues. So, boom, fish exposion. That's all I got. I leave you with this: URL_0"
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nrq3jt | Aging: how does it work? How does the body/cells one day know to start deterioration instead of growth? Why, when I'm young, can I regenerate tissues faster than I could in 30 years? | Basically just need an explanation as to how aging works, and why it works. | Biology | explainlikeimfive | {
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"Have you ever tried using a copy machine in an office or library to make a copy of a copy? The words come out kind of blurry even though the one you put in the machine can be read clearly. That’s kind of how cells work. Your body is pumping out copies and gets it really close each time, but over years the cells just get a little worse at their jobs since they lose a few words from their instruction manual each time they copy.",
"Think of your body’s cells like a rechargeable battery. You can recharge them over and over again but eventually they wear out. Your metabolic processes are very complex, so complex that they’re not even fully compatible with themselves. These metabolic processes damage cells through the course of your life. The damaged cells need to get killed off by the immune system and replaced. Adult stem cells divide replacing the damaged cells. You only have a certain number of adult stem cells in your body for each organ. Adult stem cells can only divide a certain number of times, limiting their regenerative capacity. The more you damage an organ, such as tanning skin in the sun, the faster youre using up your stem cell’s regenerative abilities. Your body actually starts destroying itself before you’re even born. You don’t notice this early in life cuz your stem cells are so good at repairing damage. Also, aging in this sense, & development, are 2 totally different things. Your development is controlled by timing genes. If we wanted… we are fully capable of engineering ourselves to age 30% slower. By duplicating genes we already have that neutralize free radicals and other metabolic waste, we can slow the cellular damage. We can also do things to stabilize the telomeres. We’ve had this technology for at least 20 yrs and it works the same with every animal. It’s actually surprisingly easy."
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nrq7jx | Regarding temperature, why there's a minimum of "cold" and not a maximum of hot? | Physics | explainlikeimfive | {
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"The terms \"cold\" and \"hot\" are relative terms that you are using to describe cooler and warmer temperatures compared to your current temperature. You can compare them to \"slow\" and \"fast\" when you're moving. There's a minimum speed, too, and you call it \"stopped.\" This is what 0 Kelvin is for temperature: All atoms have stopped moving. You can either be moving or not moving, but there is no such thing as \"negative movement\" (at least, not in a world without time travel, and even then it gets weird). This is why temperature has a theoretically infinite value above zero Kelvin, but not below.",
"Temperature is defined as the average kinetic energy of particles in a given space. So essentially how fast the particles move. Absolute 0 just means that particles don't move anymore. At a certain temperature atoms would desintegrate. That's not really an upper limit but still interesting. Conditions like that existed shortly after the big bang and they're being reproduced in particle accelerstors",
"Absolute zero is where it is so cold atoms no longer move, removing all disorder which makes it so that things cannot get any colder and if spread across the universe would lead to what is called \"heat death\" of the universe where no atomic activity would occur. Current understanding of cosmological physics places the highest possible temperature at 1.416785(71)×10³² kelvin. At which point particle energies become so large that gravitational force would be as powerful as the other fundamental forces. There's no current theory on how matter would function at these temperatures, but it has been postulated that it would cause a \"big crunch\" as gravitation collapses the universe leading to another \"big bang\".",
"One exists in theory but temperature is indistinguishable from energy in some regard. Temperature is a measure of particle motion and increased temperature means increased particle motion. The more energy the particles have in their motion, the higher the registered temperature. If you increase temperature enough the energy of the particles exceeds the strength of the bonds between them and things separate into a soup of atomic particles called plasma. You can heat further and things begin to disassociate further and the physics of it get wonky and the temperatures involved are unimaginably high. But there's a physical limit in today's physical framework. It just doesn't make sense to discuss it as such because there's not way to have something that hot and no way to measure it if it were. The center of your hot pocket would have to be hot enough to collapse into a black hole to reach this temperature."
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nrqfqq | Why do we not taste the sodium in sugar free soft drinks? | Chemistry | explainlikeimfive | {
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"You do. If you took it out it would taste worse. At very small quantities we don’t perceive salt as salty, we perceive it as enhancing other things (notably sweetness in this case). This is why almost everything has at least a small pinch of salt.",
"There is sodium in your drinking water. A regular soft drink only has slightly more than that. A diet soda has only slightly more than that."
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nrr3br | How do water softener systems work? Are they magic? Adding salt gets rid of other minerals. . . HOW? I've never understood this. I'm 54, male. | Chemistry | explainlikeimfive | {
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"Here's how I would explain to an actual 5 year old: The beads in the softener have millions of little hands. They hold onto regular old salt until something they like better goes by (like hardness or certain other things). When they're full of things they like and you want them to let go (regenerate), you put a lot of salt in there and they let go of the things they had grabbed onto because they want to touch all the salt going by. When the the salt is starting to run out at the end of the rinse, there's nothing left but salt to grab onto. So they hold onto it until something better comes by. Rinse and repeat (literally).",
"There's other systems for dealing with hard water, too. The \"H2FLow\" anti-scale system employs \"Template Assisted Crystallization,\" which uses resin beads to accumulate dissolved calcium compounds into larger particles that don't stick to pipes & shower glass, but it needs a carbon filter in front of it to remove chlorine from the water, and the carbon filter needs a sediment filter in front of it, to keep from clogging the carbon filter - so you end up with three filters in series. I've got two sets of these to condition the water coming into my house. The classical \"ion exchange\" system to treat hard water at 10gpg (grains per gallon), you end up with 80mg/liter of sodium, about 4x the recommended limit for someone on a low-sodium diet. Some of these systems produce water with up to 300mg sodium/liter (reference below). URL_0",
"There is another sort of water softening system. This uses polyphosphate salts and was common in laundry and dishwashing products. The polyphosphates bind to the magnesium and calcium ions in hard water, preventing them from reacting with soap to form scum, or precipitating out to form scale. The polyphosphates are in the product, and dont need extra equipment such as columns or filters."
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nrrn5l | what makes a housing bubble collapse so bad for the "everyday person"? | I've been reading about housing bubbles and I don't understand why they are bad and ripple through the economy. Say I own a house and the bubble collapses, how does this impact me? Wouldn't I still pay the same mortgage? True, the housing value might drop and I'd be overpaying but I'm still paying the same amount as before... right? | Economics | explainlikeimfive | {
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"Well, each situation is different, but lets look at the \"Great Recession\" in 2008. What triggered that housing bubble and collapse was mortgage companies coming up with inventive ways to get people who couldn't normally qualify to buy a house approved. This caused more people than normal to be buying houses. This causes housing prices to skyrocket creating the bubble. What the banks thought was, well, if they end up not being able to make the payments, the housing market is doing great, they can just sell the house and get out of the mortgage they can't afford right? Sure, all well and good. Until a huge number of those under qualified borrowers all tried doing that at the same time. Now, there are way more houses on the market with borrowers who can't pay their mortgages, and they can't sell their houses because of how many of them are on the market. So the prices go down. So now, borrowers just stop making payments and walk away from these houses they can't afford to pay on, and go back to renting. Then, the banks get stuck with all these unsold houses that they also can't sell because the market has collapsed. This causes banks to go into \"save my butt\" mode and stop giving out loans to anybody but the highest of qualified people. So now, even people who normally would qualify and would normally be able to afford the payments, can't. Also, small businesses who need loans to help expand and stuff, can't get loans, because the banks are broke. Eventually, this leads to several banks going under (like Washington Mutual) and bailouts by the federal government. All this means that the common person can't get loans for anything, money is tight, people lose their jobs, etc, etc. Hence, its bad for the every day person.",
"Housing bubbles bursting can be great for those of us on lower incomes...But the truth is the wealthy often come in and eat up the cheaper housing again, and so the wheel ever turns.",
"It’s bad because too much of the economy is not based on solid goods but based on finance. A lot of finance is based on the price of housing. When houses go down in value, the economy loses value. When the economy loses value people lose jobs. When people lose jobs they cannot pay their mortgage. When they can’t pay their mortgage the economy does worse."
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nru17x | How does land ownership work on the Moon? | Other | explainlikeimfive | {
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"The United Nations Outer Space Treaty (1967) forbids nations from claiming territory on the Moon or any other celestial body describing the Moon as a 'province of all mankind'. So the US for example by treaty agrees that it can't claim the Moon or part of it as sovereign US territory despite having planted a flag on it. This will change eventually when lunar travel is frequent and easier and things like permanent bases and mining settlements become possible. By this point new laws and international agreements will have to be written. The treaty places no such limitations on private ownership, but schemes to sell Lunar land claims are dubious at best. Having a piece of paper that claims you own a 100 acres of the Lunar surface is highly unlikely to hold up in any international court. You essentially have to physically go to the Moon to stake a proper claim.",
"There isn't a concept of land ownership on the moon. Whoever builds something there first will control it. But that would spark a nasty space race, its not a priority for anyone to make a national moonbase",
"Realistically, whoever is willing to defend a claim with force is the one that owns it. Right now the law says nobody owns the moon, a lot like nobody owns Antarctica, but in the future if people live on the moon and start mining or building on part of it that law is going to be challenged."
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nru1bi | Why do some things melt and others burn to a crisp | Pretty much the title. For example, When being burned wood burns to charcoal but things like metal melt and turn into a liquid? | Chemistry | explainlikeimfive | {
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"First of all it's worth noting that the way things react to heat here on Earth is heavily controlled by the air around us. The air does a lot of things. First, it squeezes things together, which is called atmospheric pressure. In the vacuum of space, most things can't become liquid because without the air squeezing it together the atoms don't stay around each other in that \"liquidy\" sort of way. Another thing the air does is provide oxygen. Nothing burns without oxygen. If you heat a piece of wood in space, it will never burn no matter what you do. If we're talking about things on Earth though, the answer is basically that all solids have one temperature at which they'll stop being solid, and if it can interact with oxygen it will have another temperature for that. The question then becomes which one is lower. Wood burns at a *much* lower temperature than it would take to make the entire log something other than a solid. On the other hand, metal, which is far more stable on its own and less likely to interact with oxygen, will turn into a liquid first (metal can still burn but it's very slow and takes more oxygen than the air can usually give it).",
"It’s the difference between adding heat and reacting to oxygen, and just adding heat. If the thing you’re heating up changes to something else with oxygen+heat then it burns, turning into some other combination of things (ashes and carbon dioxide)"
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nru3nn | How and why do people 'see' a malicious, demonic presence with their eyes when they get a sleep paralysis? | I didn't take this seriously until I had sleep paralysis myself... ad oh boi! There was a frikin dark pool of black standing near my door lol. I thought it was for real XD So... yea, how does it happen? | Other | explainlikeimfive | {
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"It's a dream. Part of your brain is awake and part of it is still dreaming. A sleep demon, a hag crushing your chest, an alien abduction, they're the same experience with different costumes.",
"Its also weird because sleep paralysis is almost exclusively a negative experience with these similar descriptions of “evil” entities in the majority of the cases",
"the unpleasant nature of finding yourself experiencing sleep paralysis seems to put most people into a place where they interpret the event negatively."
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nrugue | In a hypothetical frictionless environment, if a very large gear were attached to a very small gear with zero weight, would the large gear be easy to turn? | Physics | explainlikeimfive | {
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"There would be some mass to move as well as friction - you’ll need rotational acceleration to turn your big gear. The force needed would be determined by the density of the material it’s built from Edit: once it’s moving, in your frictionless environment, it won’t slow down either",
"I think you might be getting \"friction\" confused with every other conceivable law of physics that apply to objects in motion. Zero friction would give you great gas mileage, but it would still take energy to move a mass from one point to another.",
"Imagine the gears are on very good bearings... it’d be a little easier than that. They still have mass/inertia to overcome in order to accelerate them.",
"Not necessarily, you also need a lever longer than the radius of the smaller one, otherwise it would be the same or even harder than just moving the bigger one by pulling on the edges. The lever is what makes it easier, but the size of the smaller wheel determines how long the lever needs to be in order to make the job easier (it also determines how many times you'll have to turn the lever to make a full turn of the bigger wheel)"
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nruq9z | How can we be completely sure that a number is really infinite and does not end in millions of additional digits? | Mathematics | explainlikeimfive | {
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"I presume you’re asking how we decide whether a number’s decimal expansion is infinitely long, not whether the number itself is infinite (which is impossible, since all real numbers are finitely large). The general answer is that we can’t prove that the decimal digits will go on forever simply by computing those digits, because, as you note, they could always end at some point beyond our calculations. So we resort to using other techniques to prove that a number’s decimal expansion is infinite. One way is to prove that the number is irrational, which is usually done by contradiction: you assume it’s rational and show that this assumption leads to a contradiction with itself or other known facts, which then means that the assumption is false, i.e. the number is irrational. But there are also rational numbers with infinitely long decimal expansions, eg 1/3 = 0.3333.... To prove that the decimal expansion of 1/3 is infinitely long, it’s enough to show that the decimal expansion 0.333... equals 1/3 (which is done by considering the infinitely long decimal expansion as the limit of a sequence of finitely long decimal expansions and showing that the sequence converges to 1/3). It’s also worth noting that decimal expansions aren’t necessarily unique, so some numbers can have both finite and infinitely long decimal expansions; for instance 1 = 0.999... (which can proven using the same technique mentioned for the case of 1/3 = 1, that is, considering the infinitely long decimal expansion as a limit and proving that the limit is 1). This non-uniqueness of decimal expansions is yet another reason mathematicians generally don’t find decimals to be particularly useful in theoretical work.",
"I'm assuming you mean irrational numbers, so I'm just going to prove that a single number with infinite decimals exist. Let's use the square root of two. Any number with a limited amount of decimals can be represented with a fraction of intergers, a quick way to think about it is the number 1,23 is 123/100, 1,234 is 1234/1000 and so on. So now since we know that any number with a finite numbers of decimals is a rational number and we are claiming square root of two *(sqrt(2) from now on)* is a number with a finite number of decimals then this means square root of two can be represented as a fraction. So we say that sqrt(2)= P/Q where P and Q are positive intergers. We can make sure that P and Q are one even and the other odd by reducing the fraction (the same way we can say 6/4=3/2, 6 and 4 are both even but 3/2 one is even and the other one is odd) EDIT/CORRECTION: we can't make sure P and Q are an even and an odd number (since 3/5 doesn't have an even and an odd) but we can make sure that they don't have common factors, meaning both numbers can't be even since if both are even we can reduce the common factor of 2. So either both are odd or one is odd and the other is even. So now we square both sides of the equation and get that 2=P^2 /Q^2 2* Q^2 = P^ 2 So if P^2 can be written by an interger times 2 then it means that P has to be even. So we know Q has to be the one that is odd. Since P is even then we can write is as 2*M where M is an interger and therefore P^2 = 2^2 * M^2 = 4* M^2 Ang going back to Q we get 2* Q^2 = 4* M^2 and moving the two we get Q^2 = 2* M^2 which now tells us Q is an even number since is is the result of 2 times a positive integer for the same reason P was. This is an inconsistency since we specifically selected P and Q from one being even and the other odd. So from assuming sqrt(2) could have a finite amount of decimals we got to an absurd of an odd number being even. Therefore sqrt(2) must have an infinte amount of decimals. Similar demonstrations can be done with other numbers but this is just to prove that numbers with infinite decimals do exist."
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nrva51 | How can pickles be zero calories? | I just was eating from a jar of pickles that said serving size of 3 pickles equals zero calories, which would then have to mean that the entire jar of pickles equals zero calories right? How can this be? | Chemistry | explainlikeimfive | {
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"The 3 pickle serving will fall under what needs to be declared on the labelling (5 calories). This can be seen more extremely with Sugar in the mints Tic Tacs The serving size is one piece. Federal regulations require that any amount of sugar in excess of 0.5 grams per serving must be reported. Each Tic Tac weighs in at 0.49 grams. That means none of the sugar needs to be reported, allowing the candy to be legally marketed as “sugar-free.” despite being 97% sugar.",
"Food manufacturers are allowed to say zero calories for anything less than 5 calories. So 3 pickles may be 4 calories and they can say zero. An entire jar would be several calories but they don’t have to list how many calories per jar, just per serving.",
"Cucumbers are 95% water, and water has no calories and vinegar has practically none. Seasonings have next to none. Also anything that's less than 5 calories per serving is allowed to say it's zero calories so a serving maybe say three calories and there might be 20 servings of pickles in a jar so the jar could actually be like 60 calories but they are allowed to call an individual serving zero calories",
"American food labels are deceptive with labels. You can buy the same food, same brand, same size in a US supermarket and a local import supermarket. The calories are much more exact on foreign nutrition labels. (As in you’ll see something labeled as 243.8 calories per serving, instead of rounding it up to 250 or down to 240) American nutrition labels are just plain deceptive for marketing reasons. Read the labels closely. Chances are it’s listed servings per ounce too. An ounce of pickle is about 4 calories, so can legally be listed as zero calorie. Even if the pickle is huge and weighs 5 ounces, the label will still call it zero calorie and say serving size is 1 oz - so the average consumer is deceived into associating the pickle as a zero calorie food, despite it having 20 calories overall once it’s added up, not factoring in that hidden calorie knowledge."
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nrvk5w | Why do companies buy and sell your information? What do they do with it | Economics | explainlikeimfive | {
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"Advertising. They want to target ads specifically for you for goods and services you might be interested it. Sometimes it’s just banner ads, sometimes you’ll get unsolicited phone calls, but it’s always just for advertising/marketing purposes.",
"So google today knows - at every periodic interval - how many people searched for \"buy engine oil for toyota car\". They also know different aspects of these people groups - for example they know the age profile, gender, location, likes and dislikes, past activities, past purchases, recent interests etc. Much of this information is anonymized in a way that it is pinned to certain groups rather than individuals. Now if you own a engine oil filter company - you might want this data from google. This will help you create a heat map - showing which locations, age groups etc. should you target for your product. Based on the data analysis - you may create an online / offline campaign to sell your oil filters to these people (who will start seeing your advertisements on their feed when they search online for oil change / engine oil etc). This is a relatively innocent example. The same data can be used to target people with specific \"agenda\" messages - like anti-vax, brexit, voter fraud etc. So now you know that the data itself is like a knife - neither dangerous nor beneficial - it is the use / user of that data that makes it dangerous or beneficial.",
"Mostly for analytics and statistical data. Companies, such as the SCL Group, sell such data to advertising, media, political campaigns, social media, pretty much anyone. The trend is now data mining and behavioral consulting businesses who will use this data to build strategies in other industries, such as marketing. However, there have been massive scandals recently in how this data is sourced. *Cambridge Analytica*- a subsidiary of SCL Group- was caught hacking tens of millions of Facebook accounts using Russian software. The subsidiary was set up by Steve Bannon *(Trump's campaign strategist, WH CoS)*, the Mercer sisters *(Republican funders, propagandists)* and Alexander Nix *(political consultant, SCL director)* for the purpose of studying social media users political leanings during the 2016 Trump campaign. Then they would use the results to dissiminate false information back onto Facebook to manipulate the voters. Facebook users would be clicking on game apps and surveys enabling Nix's software to infiltrate accounts accessing their personal content, which isn't illegal technically. So when they were caught, the UK government just kicked them out the country and they then just set up shop elsewhere, hiding in a chain of other subsidiaries. They would also sell this data to call centres and marketing companies. Hence, why you get these annoying cold calls. Media franchise also use this data for their demographics, as in news, TV content, etc. A good example is this BS about *\"Covid being a biotech weapon released by a Wuhan lab\"*. Conservative strategists have clearly used such data to build a narrative on social media as weaponized information for their own political gain. If you don't want people accessing your online content and accounts, stay away from surveys and apps and start using anonymously."
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nrvz3t | Why do men have nipples? Like are they the same as women having nipples? Do they have any other purpose outside of just being another part of our bodies? | Biology | explainlikeimfive | {
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"All humans start as female in the womb. It's only after parts like nipples and vagina form do male characteristics start to assert. The 'dick vein'? That's where our vagina sealed up."
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nrwjej | Why do vinyl records always spin at 33 or 45RPM? Why not every any slower speeds that would allow for more music on each side? | Technology | explainlikeimfive | {
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"There's a trade-off between the speed of the disc and the quality of the audio stored on it--if you spin it slower then less of the vinyl will pass under the needle every second, so to get the same quality you'd have to have more detailed vibrations in the groove. Having said that, 33 and 45 are not the only speeds ever used. Many years ago, when manufacturing techniques weren't as good as they are now, in order to get decent quality the records had to spin at 78rpm. There was also a brief-lived record format that spun at 16rpm, but the audio quality was so bad it could really only be used for spoken voice and the like, not music.",
"The slower a record turns, the worse the audio sounds. Due to this, in order to provide the best sound possible, the record needs to turn faster (higher RPM). However, when a record turns faster the amount of information it can hold on a record is reduced thus having a shorter playback time."
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nrwrwq | How does chrome take 4 gb of ram? That is like 5 full movies. | Technology | explainlikeimfive | {
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"Since the introduction of Javascript websites are not just content shown to you. Websites are full on programs - some of them very complex with thousands and thousands of lines of code that is run by your browser. Look at Facebook - the website is an instant messenger program, a media player, an image viewer, a tracker (I'm sure a lot of the workings of the site are about tracking your interactions in minute detail), and a rich advertising program - and this is all running on your PC for every tab you have open. So you're not just holding the content, you're holding everything to make the website \"program\" run. Websites couldn't be as dynamic and responsive as this if they were just rendering content.",
"Every tab and extension in Chrome is divided into its own process, so if one crashes, it doesn't take down the entire web page or all of your open tabs at once. This is much more convenient for you, but it may cause Chrome to consume more memory because it must replicate some operations for each tab. Other things are going on behind the scenes as well. For example, Chrome's prerendering functionality uses more RAM, but it speeds up the loading of your web pages. Additionally, certain extensions or websites may leak memory, resulting in increased RAM utilisation over time.",
"Speaking about the computer industry in general there has always been a balance between the cost of development time vs the price of hardware. Back in the 80's and early 90's RAM was extremely expensive. A reasonable computer might only have a few kilobytes of RAM, up to several megabytes by the mid 90's. The cost of storage (hard drives) has always been an order of magnitude cheaper. To make software fit on a computer developers had to be very clever in finding ways to maintain efficiency in the code. Using what little RAM they had as effectively as possible. Come the 2000's and suddenly the paradigm shifted completely in the other direction. Computers now have several GB of RAM as standard so developers now spend more time on features and performance vs efficiency. Computer programs today are also orders of magnitude more complex than in the 80's. A developer axiom is \"computer programmers are lazy\". What's meant by that is don't re-invent the wheel, if someone already made a wheel use that instead and save yourself some time. Pre-written code is called a library, instead of having to write code to perform a common function you can instead use code in a library to do it instead. But these libraries are often quite large when you only require 1 small part, or they weren't particularly efficient in the first place. So developers have a tendency of loading all of these libraries in memory just in case they need one. - The more you can load in RAM, the faster the browser will be. Every time you have to pull something from the hard drive it slows down your computer significantly - Websites and browsers have massive inefficiencies in them. Memory leaks, extra libraries, redundant processes, and other crap that fills up RAM with time. Chrome doesn't control what code is on a particular website either, that's fault of that websites developer. - Developer teams can't be bothered to make it better because there isn't enough time, current industry focus is on new features (more profits) rather than making existing code better. - Extensive debugging time these days is more likely to be spent plugging security holes (playing security whack-a-mole) than making the underlying code better. - Many Web developers are fundamentally multimedia experts and graphic designers. Many are self taught, most don't have high end computer science degrees. This means that have very little understand of the underlying processes on a computer and make \"pretty stuff that works\" rather than \"stuff that works extremely well\" - More often than not it's \"easier\" to leave unnecessary libraries and crap in RAM in case you need it later, even if you aren't using it now. RAM is too cheap these days for developers to care that much. - Extra plugins and add-ons for your browser add to it's workload, and they aren't always super efficient at it. - Computers these days rely heavily on computer languages like Java, PhP, HTML, C#, etc that don't run code directly to the OS but instead run through an interpreter like the web browser. This has the advantage of making code multi-platform in that it will run as easily on PC as Mac or mobile devices. The problem with that is that they are inherently inefficient as a result because they add all these extra layers ontop of the OS to run. This in turn leads to more performance loss, and even sloppier code. In my own opinion the industry has taken a really wrong turn in the past 10 years and hasn't learned from its mistakes yet. The price we paid for adding under-powered and oversimplified mobile devices (smart phones and tablets) to our ecosystem is everything is now bloated, inefficient, and runs like crap."
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nrx8uj | Why does it seem so common so common for people to type some words / phrases twice? | I notice this online a lot and I even do this every so often. Why do we repeat ourselves like this without noticing? | Other | explainlikeimfive | {
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"I'm going to guess it's because we \"rehash\" our thoughts to guide the wording as we type. Speech doesn't give us that luxury.",
"You start a sentence and think about it while writing or editing it after writing and then you start where you left of and often enough that ends up being the same word or fragment that you've already written. And either you don't proofread at all and so it stays in or you do and make the same mistake again."
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nrxo8m | How did primitive sheep contain/deal with all that wool when modern sheep require sheering yearly? | Biology | explainlikeimfive | {
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"Primitive sheep didn’t grow that much wool. Modern sheep have been selectively bred for ages to produce an animal that isn’t suited for the wild. Kind of like cows.",
"Earlier sheep would grow less wool, and they shed it like any animal with a summer and winter coat. Modern sheep have been selectively bred to not shed their wool, so the farmers can collect it all at once. Also, most modern sheep breeds are dumber and less agile than their ancestors."
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nryt8i | Why are “conservatives” calling for Fauci to be fired after seeing his, now published, emails while “liberals” are defending him and saying he should not be fired? | Other | explainlikeimfive | {
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"Generally the emails are almost meaningless and don't add anything that wasn't already known. \"Conservatives\" who refused to wear masks, even during the worst days of the pandemic, because, they said, the scientific guidelines changed constantly, and Fauci had flip-flopped. His emails will reinforce their opinions. Fauci did indeed change his mind about health guidance, such as the wearing of masks, as more information emerged about the virus. He told someone in February 2020 they did not need to wear a mask while travelling. Later, he encouraged people to wear them. In contrast, for \"liberals\" his emails reinforce their views - that he changed his mind about what people should do to fight the virus, depending upon the scientific data, and not on what Trump wanted people to hear."
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nryz6x | . If steroid drugs like Prednisone are essentially immunosuppressants, how do they aid in the treatment of diseases like Pneumonia etc. Don't they in effect kick the body when it's already down, making it harder to fight off the infection? | Biology | explainlikeimfive | {
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"Not a doctor. Using drugs like prednisone (corticosteroid), the main effect is AFAIK suppressing inflammation. This is sort of like having a big fire destroying your house and the firemen (the prednisone) goes in and sprays a ton of water quickly (further doing damage) to put out the flames. It is to manage an acute issue - something urgent - rather than a \"cure\". The problem is sometimes the body's immune response is so strong that the response itself becomes life threatening so it does make sense to \"cool it down\". Basically, prednisone is used to buy time to allow the body to fight off the infection."
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nrz1fr | What does an MRI of the head make images of exactly, and what is it used to look at/diagnose? | Is there sometimes dye used in an MRI? What is this test used to diagnose/see versus for example a PET scan? TIA. | Technology | explainlikeimfive | {
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"MRI scans are physically mapping the concentration of hydrogen, what this means for the human body is mostly measuring water and fat. They produce a structural image for example in the brain you can see all of the grey and white matter (and they appear different which is useful diagnostically). They’re using for diagnosing pretty much anything which causes a structural change in the brain like Alzheimer’s. MRI does occasionally use contrast agents but it’s rare as most MRI imaging doesn’t require it. A PET scan on the other hand measures the distribution of the tracer you inject, eg some sugar analog with a radioactive isotope. This lets you map metabolic processes, seeing where that tracer gets concentrated in the body. For example cancer cells use a tonne of sugar because they are growing so much, so if you image them with a PET scan then they can be easily identified. My experience in this is from studying physics involving medical imaging so someone with a medical background may be able to elaborate on exactly what they can be used for."
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ns2o5q | - How do applications like Google Maps and Apple Maps know when there is a traffic jam? Where does the information come from? | Technology | explainlikeimfive | {
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"Most people have phones with location sharing enabled. They can tell what traffic is like based on how many phones are on the road and how fast they are moving. This works especially well for highways. They also have a lot of historical data to work with and a lot of mathematical models that show how traffic usually forms and how long it tends to last based on the roads and the number of people caught in traffic. This gives them the ability to make some general predictions about how much the traffic may slow you down. Of course it isn't perfect! Sometimes traffic is caused by an accident and no model can predict that an accident will occur or guess how long it will take to clear the road and get people moving again. There are many factors that can cause the algorithm to guess wrong and take a longer path sometimes. That's why some people prefer to use their own intuition and sense of direction instead of a map app.",
"As others explained, they use the data from the mobile phones of the general public... Which might sound like conspiracy theory BS, but it has been tested and proven. Here is the story of a guy with 99 phones and no car: URL_0",
"People in cars use their devices for navigation. Their devices transfer data on their location to application servers. The server part of the application analyzes this data and figures out the average current speed of users depending on location. Places with low speed and many users are currently jammed."
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ns34of | During a panic attack the fight or flight response is activated. Why is it called the "fight or flight" response if it leaves you feeling so weak, scared, short of breath and faint. Surely feeling like this is not very effective if you actually need to fight or flee? | Biology | explainlikeimfive | {
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"It's the time scale that messes it up. It's a bunch of physical changes that are supposed to make sense when a tiger jumps out of a bush and you have 4 seconds to bash it's face in or get half a mile away. It all falls apart when instead of a tiger it's worry about unpaid taxes or something that lasts for hours or days, or just unrestrained terror getting worse and worse. Hormones that make sense for 'yeah, do this thing right now!\" start to screw you up when the right now goes beyond a few seconds or minutes. You get a second of 'put all your energy into this!\" then use it to just vaguely panic because there is no physical threat then five minutes into the \"put all your energy into this\" all your energy is none energy and you are weak and out of breath and still trying to run at max power.",
"Panic attacks are a disorder. They are not how the fight-or-flight response is supposed to play out. The state when that response is triggered is called “stress”. Panic attacks are something different and much more severe.",
"People now recognize that freeze is also an effect of the adrenal response. [Here is more information.]( URL_0 )",
"Because your missing one. Its not just fight or flight, its fight, flight or freeze. Think deer in headlights freezing. Also panic attacks are a sign of anxiety issues/disorder and while it's true that is part of our emergency adrenalin reaction, its a sign that its malfunctioning. Perhaps due to trauma or perhaps the stress is chronic long term stress not an immediate threat.",
"At least part of the problem is that we neither fight or flee in a panic attack, but rather stay and stew on whatever triggered the panic attack. Our body responds with “oh, perhaps you didn’t hear me, here’s some more ‘fight or flight’ cues”. Should probably rename it “fight, flight, or fester”. Lol",
"When \"fight or flight\" is triggered, your body is given a boost of energy and strength. You can learn to use this for fight or flight. When your body has used up this energy you have to recover from it. ELI5: your body takes all the energy of the next 15 min and squeezes it into say... 5min... if you did 15min of work in 5min you'd be pretty tired right? Fight or flight, it's about energy spent."
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ns3td5 | How do people handle the line between: being an a**hole in behaviour at work who violates the boundaries of others VS. being a people pleasing nice guy who gets his boundaries violated by others (because of the fear of defending himself or the fear of overreacting) | Other | explainlikeimfive | {
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"Not sure if ELI5 version can be done because it’s…so nuanced. But I’d say treat people with respect and be nice but be firm when others try to take advantage of you or your boundaries, let them know that’s not OK or appreciated."
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ns3vml | can someone give me an understanding of why we need 3 terms to explain electricity (volts,watts, and amps)? | Technology | explainlikeimfive | {
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"Think of a pipe that we're going to pump water through. Now imagine you put your face at the open end of the pipe. The voltage is the pressure the pump puts in. The pressure will drop depending how long the pipe is. The current is the amount of water that moves through the pipe per second, the flow rate. The watts is how hard it hits you in the face, or how much it pushes you back. I could send a low pressure and high flow rate and you'd have a shower. Or I could send a high pressure and the same flow rate and pressure wash your back deck.",
"NB: The water analogy is great but doesn't explain the whole story. In the same way, my analogy works to explain a different side. Both aren't complete because, let's face it, electricity is pretty complicated. Think of balls going through a chute [like this]( URL_0 ), but without the stop at the end. This chute is always filled with an *endless* amount of balls. They just keep pouring out. The chute is quite horizontal and the balls don't really roll fast. You decide to pick up the upper end and raise it, so it stands up more. Suddenly, the balls pick up speed and go faster. The balls get more energy. This angle, this is equivalent to the voltage, for which we use the unit **volts**. Now go to lower end, take a stopwatch and count how many balls fall out in 10 seconds. 20, maybe? The more balls come out during this time, the higher the current: the more **amps**. Now, for power, remember how I said the balls get more energy? That's important, because you can do things like that, like move the pedals on your bike. If you take the amount of balls and the amount of energy each has and multiply it together, you get power: for which we use the unit **watts**. Some might wonder why I explained it like this. The water analogy is easier. Well, this analogy also explains one other thing with electricity: charge. Every ball is an electron, which has charge. The unit for this charge is **coulomb**. Electricity is electrons(balls) going through a conductor(chute), they go through with a certain energy(volts): the more energy it has, the more can go through in a shorter time(amps). If we know how much energy each electron has and if we know how many balls pass through a conductor every second, we can calculate the energy passing through the conductor every second(watts). EDIT: For everyone saying my analogy is not 100% correct, you're right. But remember this is ELI5, getting a rough grasp of the subject matter is more important than full accuracy.",
"Because they are different things. We aren't Squanchy speaking in squanch. Voltage is the charge difference between two things. Current is the flow of electrons, measured in Amperes. Watts are the combined measure of the two for power. Volts x Amps = Watts.",
"The three terms we actually need are volts, amps, and *resistance*, which is opposition to current flow (amps). The reason we need these three terms to talk about electricity is because they are dependent upon each other. If you have a known voltage, the amount of current that will flow is dependent upon the resistance. More resistance = less current flow. Less resistance = more current flow. Power (in electrical terms) is the ability to do work, and is calculated by multiplying volts times amps. It actually gets a little more complicated than that but that's the basic equation.",
"Amps (Amperage) is how many pixies there are. Voltage is a measure of how angry said pixies are. Devices choreograph the pixies and make them dance. Wattage is how many pixies dance in a given time. DC pixies always go in a circle from negative to positive. AC pixies frolick back and forth. Pixies always want to dance and go to sleep in the ground. No matter how angry the pixies are, there have to be enough of them to hurt you.",
"If electricity was a waterfall, then volts would tell how high it is, amps how wide it is and watts how much water goes over the edge per second.",
"Electricity flows in much the same way water does. Volts is like the pressure in a pipe. The higher the volts the more force can be applied. Watts is the amount of energy per second so it is like the energy you can get from the flowing water. An amp is an amount of charge flow per second. So it is the amount of water flowing in gallons.",
"##Electricity :: Water Electricity is like the water in a waterfall that is spinning a mill wheel. You need two things to run the wheel: 1. a lot of water. 2. for that water to be falling. ###Waterfall Height :: Elecric Voltage Voltage is how tall the cliff is. You can get more power from each drop of water if it's a tall cliff, but that doesn't tell you if there's actually a LOT of water or not. ###Amount of Water :: Electric Current Amperage is current, it's how much water is actually flowing. It's how wide the waterfall is. More water means more power, probably, but you still need the water to actually be falling, otherwise it's a pond and you can't run a watermill with a pond. ###Wattage is Total Power, influenced by both amount of water (amperage, electrical current) and by the height the water is falling (voltage) Multiply the two together and you get wattage, which is how much power you actually are getting. How much that waterfall is actually going to move the watermill. Niagara Falls is a huge river (current, or amperage) with a tall cliff (height or voltage). It could power a huge watermill. A small but tall waterfall (low amp, high voltage) is useful, and so is a huge lazy river (low voltage, high amperage). A tiny lazy river (low amp, low voltage), not so much. Final factlet: static built up on a balloon has really high voltage, but very low amperage. It's like someone hitting you with a single drop of water at really high speed. Doesn't actually hurt, but only because there isn't very much of it.",
"* We need voltage (volts) and current (amps) to describe electricity. * Watts is a measure of power that is commonly used for electricity, but it's not strictly for electricity. * You can describe any source of power in watts. * So to counter OP's question, we don't *need* watts to explain electricity. * We could just use \"Volt-amps\" as the unit. * But using a term like watts to neatly represent volt-amps is easier.",
"The old water pipe analogy: Volts is the \"pressure\" of the water. (technically the pressure difference... if you pumped the water back down the pipe harder than your water company pumped it towards you, then the water would flow the other way, wouldn't it?) Amps is the size of the pipe. Watts is the total amount of water flowing through the pipe. It's a combination of the pressure and the size of the pipe. Big, high-pressure pipe have far more water flowing through them than small, low-pressure pipes, or big low-pressure pipes, or small, high-pressure pipes. The bigger the pipe (amps/current), the more water can flow through it. The higher the pressure (volts), the more water can flow through it. (And resistance, the one you missed off, is the obstructions/difficulty of pushing water through the pipe... imagine a very crusty old pipe where the water can't flow as well through it because it's 90% limescale. If the resistance is greater, it's effectively like having a smaller pipe, so you get a lower current through it, and the harder it will be to push lots of water through it). Big pipes (circuits with high current capacity) can happily supply small amounts of water (low current) but small pipes (low current capacity) cannot supply large amounts of water (high current). To know the total power (amount of water) that you're putting through the circuit, and the amount it can handle, and the amount you need, you need to know the size of the pipes of each part (the current) and the pressure you're pushing that current down there with (voltage). If you only know the pressure you're pushing, that's not enough. The pressure on one pipe would be fine, but on another it may blow it apart. If you only know the size of the pipe, that's not enough. A large pipe will handle high pressure well, a smaller one will tear itself apart. So you need to know both. And some pipes have a size that can't be made any larger (e.g. in your computer/phone, there are paths that can only handle so-much current because of their small size), so you have to know and control how much water/power could go through them. And some \"power supply\" devices (water pumps) can only give a certain pressure (e.g. batteries can only push a small voltage, mains electricity can push a larger voltage, and substations can push an even larger voltage), so you need to know what pressure can be taken by each part, and how to move from high to low pressure (e.g. by increasing the size of the pipe) and vice-versa. And, when combined, pressure and pipe size will tell you the total amount of water - the power you're putting into the system, and the power going into each part. Watts is \"unnecessary\" in that sense. As is resistance (Ohms). They can both be worked out from the other two. But you need at least two, and then the others will reveal themselves to you. Power = Voltage x Current (stated as P=VI) Voltage = Current x Resistance. (stated as V=IR) Pick any two and you can calculate the third / fourth from them. So technically only 2 measures are essential. And voltage/current appear in both, so they are all you need.",
"ELI4. 'Can I drop a rock on your foot?' 'MUM, TIMMY WANTS TO DROP A ROCK ON MY FOOT.' 'Timmy, why do you want to drop a rock on your sisters foot?' 'It's an experiment, mummy.' 'Show me the rock.' 'Oh, alright. See, it's not very big. Can I? Please?' ... 'Where are you going to drop it from?' 'Nevermind.' While volts and amps are important quantities, in isolation, they don't tell you a lot. But power is a useful quantity in it's own right as it tells you how much work, or heat, or pain is going to be generated. Just like driving a nail into a block of wood you can use a small tack hammer and swing it lots of times, or you can use a large hammer and hit it once. It's all about the nail. Or the foot.",
"Electricity is the flow of \"charge\", or more specifically electrons. Electrons have a negative charge. Just like poles on a magnet, alike charges will repel each other so if you have \"too many\" electrons in one place they'll want to move down the line until they are evenly spaced out. Voltage describes the difference in charge (number of electrons) between one place and another. Obviously those places need to be joined by materials which will allow the electrons to flow which is why you need to physically join those points with conductors in order to get any electricity. If you have no difference in the number of electrons, then there's no incentive for any of them to move and you have no flow (no electricity). The larger difference you have between two points, the higher voltage you have and really this describes the available \"pushing force\" in your circuit. I think an easy way to picture \"voltage\" is with your experience of static electricity. Electrons are the tiny, outer-most particles of an atom which means they're easily displaced (transferred from one atom to another). Let's say you're walking along an insulating carpet in insulating shoes. The electrons making up those atoms can be easily transferred and so before you know it you have an \"excess\" of electrons stored on you, but because they have no easy way to flow, they stay stored on you... until you touch a conductor. Now all of a sudden those excess electrons have an easy path to somewhere with fewer electrons and you feel a shock as they rapidly do. The other example is the classic \"rub a balloon on something then hold it near hair\". The same transfer of electrons happens through the rubbing, but because you haven't given them any way to flow what you see, as you bring the balloon close to the hair, is the electrons in the hairs atoms being attracted to the balloon because the balloon has lost a lot of its electrons through the rubbing (they want to move to the balloon, but can't, at least not easily). Amperage describes how quickly that charge (electrons) passes through the circuit. If you have a nice thick wire which will allow lots of electrons to pass through it at once, you'll have a high amperage. If you have a very thin wire which limits the flow of electrons through it then your amperage will be lower, even though the voltage (the \"pushing force\") remains the same. Wattage is a measurement of energy over time; while I've explained Volts and Amps in terms of the number and movement of electrons, wattage makes more sense when you introduce Voltage as a measurement of stored energy. Volts = energy per electron, and Amps = electrons per second (well, sort of, electrons are tiny, so they're actually measurements of millions of electrons rather than a single one). If you multiply that \"pushing force\" by how quickly the electrons are actually moving through the circuit (energy per electron, and electrons per second) you'll get an \"energy per second\" (Watts) result.",
"[ URL_0 ]( URL_0 ) & #x200B; this is the easies way to understand i found out.",
"Think of it like water. Voltage is like water pressure or how many psi your faucets have. This is important because low pressure might not provide enough force to do something, and too much pressure might break things. This is Why electronics require a certain amount of volts, but not too much. Amps is like speed, how many miles an hour your water travels down the water line, it is determined by the pressure (and the resistance, which is like how wide or skinny the pipe is). This is important because a high water velocity can be dangerous even if the pressure is low. Watts is like how many gallons per minute you get out of the faucet. It is determined by volts multiplied by amps. This is the unit used to describe exactly how much power a given device uses, theoretically you could lower voltage and increase amps or vice versa and a device could keep running until it runs into the aforementioned problems with low or high volts/amps",
"Imagine you’re giving away free money in your store today. You’re gonna have a flow of people going through your door. Voltage is how much money you’re giving per person (relative to how rich the people are). If you offer 100 dollars per person people will come really fast, very motivated. 10c per person, it won’t pull people as much. When you see electricity jumping - blue sparks like static or lightning , this is a high voltage. Like if you offer a million dollars per person people will literally jump over rivers to the avoid the queue for the bridge. How many people are passing through thru your doors each second ? This is current , amps. It will depend on how money you’re offering (volts) and narrow your doors are (the Resistance of the electric cable). Ok then imagine some clever criminals hear about your promotion. They wait on the street to rob everyone leaving the store. But they can only do it for an hour before the police will come. So they need to know how much money they can potentially make per hour to know if it’s worth it. They do “money per person” (volts )multiplied by “people per second” (current , amps) That is power, watts. It’s the rate at which money / energy is flowing. Then to workout the total money in an hour , they times this number by 3600 (seconds in an hour). Now they know the total amount of money moved in an hour. This is an amount of money / energy, can be called a watt hour , (or a kilowatt-hour is 1000x this) and it’s how the electricity company charge you."
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ns4blz | How does practice actually improve reaction time? What is actually going in the brain? | Biology | explainlikeimfive | {
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"Before practise: Brain makes many calculations, each of which add to total reaction time, to perform task. After practise: Brain has created automatic systems to handle calculations, no longer must actively perform these calculations, so reaction time is not as long.",
"As you learn to do a thing, your brain is making connections between neurons (brain cells). As you practice the thing, those connections get coated in a sheath of material called myelin. Myelinated connections carry the impulse faster."
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ns4z1z | Why is pointless work more mentally taxing than working with a purpose? | The other day I was crunching some numbers and couldn't get them to add up, no matter how hard I tried. I did this for a few hours and afterwards I was exhausted, like when you're ready to go to sleep aftee physical exertion. Usually these kind of things add up nicely and slowly but surely things just fall in their places nicely like a puzzle. When that happens, working is a breeze and even rewarding. What is the phenomenon behind this? Why is pointless work so much more mentally taxing than working with a purpose? | Other | explainlikeimfive | {
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"Knowing you’re working is one thing. Knowing you aren’t wasting your time is valuable. Knowing you’re working on a thing that is _definitely_ a waste of time makes it difficult for many people to be motivated — because it’s not useful _or_ necessary.",
"Dopamine. Doing something new and/or interesting releases dopamine in your brain, which feels good and refreshing and energizing. Non-interesting, repetitive work doesn't give you that boost.",
"There are two factors at play here: laziness and flow. Laziness, because evolution optimizes for efficiency and one of the easiest ways to optimize a person's behavior for energy-saving is to reward productive work and not reward pointless wastes of energy. You do all the work and you don't get your dopamine at the end, everything you did retroactively feels worse in your memory because of all the effort you expended. And flow, which is that mindset of super-focus that comes when a task is equally matched with your skill. When you get \"in the zone\" with your work, you're being worked hard enough to be challenged (and thus not bored), but not beyond your ability to actually complete the task (and thus not anxious). In your case, it sounds like the task was unusually difficult, so a normally \"breezy\" task suddenly ended up causing anxiety."
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ns5wqv | how are there more than 2 genders? | I just don't get that. There's male, female and... what? Please explain | Other | explainlikeimfive | {
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"So this is gonna get deleted by mods I bet, but here goes: The concept is that gender is a social construct separate from physical sex (although there are also people proposing that physical/genetic sex are artificial social constructs too. Basically, because the male/female genders are ideas created by people, its possible for people to create more than just the two to cover different social positions/feelings/concepts.",
"You’re probably going to get a lot of hate for this VALID question, but the way it was explained to me in uni once was like this; Sex is what you are assigned/the parts you have/biological attributes - Male/Female Gender is your identity and “socially constructed roles” behaviors and expressions. Gender can be as simple as girl, boy, woman, man. I’m very unfamiliar with all the genders people use to describe themselves but this helped me understand the difference between gender and sex as i feel that’s where a lot of people get confused. I hope this helps you and i hope people are not dense enough to send massive hate your way for a simple question with no attached bias or opinions on your part.",
"The idea is basically that genders are social constructs. Since they're not dictated by anything physical, they aren't really tied to biological sex. Think of them more like labels that people chose to use rather than something people definitively *are*. Incidentally, there are more than two biological sexes. Those that aren't male or female are fairly rare, though.",
"Humans use abstractions to represent objects and ideas in the world. Different abstractions are useful for different purposes. For example, sometimes it is useful to use integers for certain maths, while other times we need to use real numbers (numbers with digits after decimal point). Gender expression is just a model that humans use to represent how we act in certain social situations. Sometimes it is useful to expand the traditional binary model into a continuous model where gender is represented along a spectrum. The “what” you are questioning is just anything along the spectrum that doesn’t fit into the rigid male-female binary model.",
"It depends on how you define gender. If you define gender using the precense of certain sexual organs there are a lot of different defects which would make someone not fit into either of the two genders you define. Even if you define gender as the precense of a Y chromosome there are still people where this is a dificult thing to determine and might even require further specification. But both of these definitions are very clinical and not very useful in everyday use. The problem is that when most people think of a man or a women they associate this with certain properties because that is how we have been raised in our sociaty. The problem is that a lot of people fall far outside of these normal properties that people assign to each gender. So it does not make sense to give them one of these two labels that everyone needs to fit in."
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ns70df | Why does blowing a raspberry at a CRT monitor make the screen seem like it's flickering? | When I was in elementary school, I remember CRT screens seeming to flicker when I blew raspberries. Curious what causes this optical illusion! | Other | explainlikeimfive | {
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"Older CRT TVs displayed images in an interlaced pattern, meaning they display all of the odd number lines on the screen, then the even number lines. (Current TV screens display in progressive pattern, where you get all lines of resolution displayed at the same time..clears up diagonal lines). The screen flickers because your raspberries vibrate your eyes a little, which are at a different speed than the screen refreshes. Something will happen when you're eating something crunchy, or filming the screen.",
"CRT monitors work much differently than modern LCD screens. CRT stands for \"cathode ray tube.\" What is happening inside of this tube is that electrons are being fired onto the screen in a steady stream. The cathode at the back of the monitor fires the electrons in a stream called a ray, and electromagnets are used to control the direction of the ray to make it hit specific parts of the front of the screen and \"light them up.\" The front of the screen is made of materials that are florescent, and glow with light when energized. This ray goes from the top of the screen to the bottom, row-by-row, pixel-by-pixel, to make a complete picture (nerds: I realize this is technically interlaced but this is ELI5). It has to do this quickly enough so that your brain perceives one image. It also has to do this whole process several times a second so that you don't notice the image fading away as the energy from the electrons dissipates. The rate at which the screen \"refreshes\" the image is called the refresh rate. This fading effect doesn't happen on LCD monitors. The pixels stay constantly lit by a light behind the screen (the backlight), and the only thing that changes is the brightness and darkness of each pixel. Think of it like closing and opening the blinds to block out varying degrees of light. The light never goes away, it just changes in intensity based on how open the blinds are. It still does this row-by-row, but there isn't a loss of brightness in between each update like there is with a CRT. Now, when you blow raspberries, you're creating a strong vibration in your head. That means that your eyes are moving up and down rapidly. This can create an effect where you actually see the CRT screen refreshing, and the \"oldest\" pixels fading out. This is especially likely when the refresh rate of the monitor is low, as was the case with most cheaper CRT monitors. I don't know for sure, but it's likely that your brain is having a hard time \"filling in the gaps\" like it does normally, so what you see is the \"raw data\" that your brain isn't able to process as effectively before you perceive the image. Fun to think about! Great question."
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ns887f | Difference between Focus vs. Concentration | > "Concentration which is not the same as focus, concentration is self-discipline." I heard that sentences, I wanna know more about the differences. | Other | explainlikeimfive | {
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"You can use a camera as tool to understand this. Focus brings objects into clarity at a specific distance, concentration is zooming into only include one object or point. It's about the intensity.",
"Focus is what you are thinking of, concentration is how hard you are thinking of it. Focusing hard is the same as concentrating. People may use the terms interchangeably even if they technically have different definitions."
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ns8rb1 | Spider venom | Do repeated spider bites from venomous spiders (such as black widows) have any kind of cumulative effect - either good (such as building immunity) or bad (accumulation of toxins)? | Biology | explainlikeimfive | {
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"It depends on the toxin. Repeated exposure to toxins does result in tolerance being built. But if the toxin does cause damage that can't be repaired, like damage to heart tissue or brain tissue then it will have an accumulating affect. If you want to know the mechanism behind tolerance, it is actually our immune system. Many toxins are just proteins. Certain toxins can be neutralized through antibodies due to this as an antibody can bond to the protein neutralizing it"
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nsb2zl | Why do tortoise live so much longer than other reptiles that may be related to them? | Earth Science | explainlikeimfive | {
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"We don't know. All we know for sure is their organs seem to age much more slowly than those of pretty much anything else. But why they do and how it happens is just not currently known to us. Its the subject of ongoing research though, so hopefully we'll have answers sooner or later.",
"There is something called the rate of living theory. Raymond Pearl based his Age of living theory upon the earlier work of Max Rubner and proposed that the maximum lifespan of an animal was related to its metabolic rate sometimes viewed as the number of heartbeats. However this may only be part of the picture with the role of reactive oxygen species in cell deterioration and eventually cell death also playing a part. URL_0"
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nsbvrq | how people with contact allergy are okay when ingesting the allergen | for example people with a water allergy who’s immune system only reacts when their skins touches water. if the immune system considers water a foreign body, why is it okay for them to ingest it? why does the reaction only happens on skin contact? | Biology | explainlikeimfive | {
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"It’s not a normal allergy but theorised to be a specific reaction caused by the interaction of water and their skin. For example possibly the water interacts with compounds in or in the skin that causes a toxic chemical release. No one knows for sure but it’s not water in the body that’s the problem."
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nsdzx7 | How is insurance both profitable and useful to a customer? | I feel like insurance makes money the same way a casino does: they don't have to pay out as much as customers pay in. If so, wouldn't it be better for sutomers to just save the money they're giving to an insurance company instead of going through the company? | Economics | explainlikeimfive | {
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"To the customer, insurance is a fixed loss to prevent a rare but potentially catastrophic loss. Insurance is built around risk pools. If 1 out of 1000 $500k homes burns down every year then the insurance company will bundle people in similar risk homes together, everyone pays $510 per year so the insurance company takes in $510k but pays out one $500k fire claim each year profiting $10k. Each person is out $510 per year, if they were to instead save that premium for 10 years they'd only have $5100 which wouldn't do them any good if their $500k house burned to the ground. The odds of their $500k house burning to the ground are reasonably low, but in the event that it occurs it would be financially devastating. In general, people cannot effectively save enough to cover what their insurance potentially covers. Insurance protects you against rare but exceptionally expensive events for a fixed cost. Its not gambling because you never \"win\", you just lessen your losses",
"The insurance company is selling you a product they don’t want you to use. You’re purchasing a product that you *also* don’t want to use, but will if some misfortune befalls you to limit your total cost. The insurance company has collected an enormous amount of data over the decades to know exactly how likely you are to actually use the insurance, and they set the prices accordingly. If you have a 2% chance of filing a claim, they’ll charge you a little over what 2% of the likely cost to them would be. Aggregated over many people they turn a profit by raising more in premium than they pay out. Most customers never use the insurance and lose money, but a few do and avoid an even greater loss. You’ll have a hard time finding insurance for things that are guaranteed disasters like a track car.",
"No. Insurance works by aggregating risk. If the odds of your house burning down are 1 in 1,000, the insurance company collects 0.11% of the cost of a house from 1,000 people. So they have 110% the value of a house. When 1 house burns down they pay 100% of the value of the house and keep 10%. Everyone else is out 0.11% of the value of their house. The person who's house burned down is not out the value of their house. If the person who's house burned down had not bought insurance, they would be out 100% of the value of their house instead of 0.11% of the value of their house. So insurance lets you pay a small amount to protect yourself from an unlikely event that would be devastating if you did not have insurance.",
"> wouldn't it be better for customers to just save the money they're giving to an insurance company instead of going through the company How much money can you save? Last time I needed to use my car insurance it paid out to the policy limit, which was more money than probably 99.99% of people could ever reasonably save. I could pay my premium for about 100 more years before they'll have made a profit off me. So in my case, I won the gamble against the insurance company. It didn't feel like winning at the time, but it was certainly better than bankruptcy.",
"Insurance is all about risk. You need to do the calculations for yourself for when it makes sense to save the money, versus when you need to pay for insurance. Insurance is ideal for things that aren't very likely to happen, but if they happen, they'll be very expensive. For example, if I die before the age of 65, my family will get $1,000,000. It costs me $50 a month for that insurance, or $600 per year. If I was just saving that money up, I'd never get even close to $1M. But if I get hit by a bus tomorrow and my family loses my ability to earn money, at least the insurance payment will make sure they're looked after. If something is very likely to happen, you either can't get insurance for it, or the insurance will be really expensive. In those situations it's better to just save on your own.",
"I've paid over $3k for my renters insurance for the past 15 years. When I recently had a theft the insurance paid out much more than that, according to my policy terms. It would have been life destroying without the insurance, i couldn't have saved that much or i would have. I think they're making money off everybody who doesn't get robbed, which is most people I think.",
"I pay around $2,200/yr for my home owner insurance. My home & possessions are valued at $450,000. It would take me 181yrs of saving my payments to have $400,000 to cover the replacement cost of my home and possessions. Say at year 10 my house catches fire, and takes $56,000 worth of damage, but I've only saved up $22,000 to cover that. And I need to pay to have someone do the smoke removal, and save the floors, and replace the stuff that got damaged... I have been living here 22yrs, so I'd have $48,400 saved up.",
"Say it will cost you $100,000 to repair your house if something goes wrong. Do you have that lying around? How about $100/month? It's the same reason we have mortgages. We're delaying the payment to get something we need now, even though with interest it'll be a lot more than the purchase price. Except with insurance, you'll hopefully never need the payment.",
"\"they don't have to pay out as much as customers pay in\" is literally every working business in the world. It's practical because it's better to pay a small amount over a long period for nothing, than it is to be completely bankrupted by events outside your control. When you claim insurance you do get out more than you put in, usually. But no everyone ever gets a pay out, so the company still makes money.",
"There's an empty piggy bank. A large group of people fill it with their money. Since there's so many people, each person only needs to spend a little bit of their money to do so. If someone gets hurt, they can take out what they need from the piggy bank to cover it. But the person who owns the piggy bank doesn't just keep the money in it. They invest part of that money to make even more money. So consumers have a (useful) backup in case something goes wrong, and insurance makes money (is profitable).",
"It's profitable because insurance companies are able to calculate what they need to charge so that they can pay out claims, run their operation and make a profit. For customers, the idea of insurance is to mitigate catastrophic risk. Over the long run, they don't expect to make money or break even but are paying a small amount over time to prevent the possibility of a huge financial setback, one way beyond what they could afford to pay or save for. Better to pay $1,000 a year you can budget for to insure your house or car than risk totaling your car, and somebody else's car, plus injuries leading to hospital bills that all add up to $100k. All you could afford was a $10,000 used car and now you're somehow able to save up $100k? Or your house burning down and costing $400k to rebuild, flooding and costing $50k to replace everything in your basement. Your house could burn down the second year you own it -- where are you going to come up with $400k to rebuild and replace your stuff? And you're still paying your mortgage on the house you bought, so you'd be paying for your house twice over basically. Isn't it safer to just know you'll spend $1000 a year on insuring it and not face such a risk?"
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nsep4r | Why does your nose burn so much when your about to sneeze and why does the feeling suddenly just go away some times? | Biology | explainlikeimfive | {
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"The burning is nerves inside your nose telling your brain \"there's something bad here, get it out\" once the sneeze is over, there's no more need to tell your brain to sneeze"
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nsfavc | Why does the body burn muscle before fat when starving? | This is something that just doesn't make sense to me. I've read many times that when food isnt available the body will burn muscle before burning fat. Why? Why would the body burn what you need to move and get food to make sure you dont starve over what reserves it has incase food isnt available? | Biology | explainlikeimfive | {
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"Our bodies don't default towards having massive muscles. Big muscles means you need more food to fuel the body. So if our bodies aren't getting enough food, our bodies go \"We've got to shrink down because we're in a famine. Burn some of that fat for energy, and also some of the muscle mass as well, so we reduce the amount of muscles we need to feed. We're in a famine, and need to get smaller so we use less food and thus are more likely to survive.\"",
"The body is doing exactly what you expect it to. At no point in your life do you need to bench press 250lbs to survive. Being able to lift 20-50lbs is going to cover 99% of all situations. Muscle takes a lot of calories to maintain. Way more than is efficient. And the bigger your muscles the more that's true. So the first thing your body does in a caloric crisis is cut its spending. By reducing muscle mass to a more manageable level. Also remember that this is bio101 stuff. Your body doesn't actually exclusively burn any one energy source. Every day you use carbs, fat, and protein. So really it's just a matter of proportions.",
"Just commented on a simile post in regards to fasting. This is simply not true. Out of the three things that your body can convert to usable energy (carbs, fat, and muscle), muscle is the most difficult to convert and is highly inefficient to use, resulting in very little usable energy for the amount it takes to convert. It is your body’s LAST choice to convert for fuel.",
"> Why? Why would the body burn what you need to move and get food to make sure you dont starve over what reserves it has incase food isnt available? Its a common myth that this happens to an extent that we can't actually move around anymore. What happens during a long term fast is eventually muscle protein breakdown will eventually overtake muscle protein synthesis(creation) due to zero construction materials(food). Interestingly enough, this isn't well studied because to perform these kinds of studies violates various ethics boards. Fasting long term could also be classified as torture methods. However they have made guesses similar to your own in which 'why would we evolve to instantly disable ourselves in frequent times of famine'. So while MPB will *eventually* overtake MPS, they guess that it could be quite some time, certainly longer than the general public is led to believe. Especially considering every cell has protein so catabolization of non-skeletal muscle cells like your skin could be of higher priority. I stress that 'we don't know' though since the ethics board comes knocking down our lab doors with shotguns when we attempt to find out. Further reading: URL_1 Further watching: URL_0",
"This is a myth. When starving the body will burn fat first before resorting to catabolism. In medical studies of patients who fasted on alternate days for 70 days straight the patients showed no loss of muscle mass. See: Bhutani et al., “Improvements in Coronary Heart Disease Risk Indicators by Alternate-Day Fasting Involve Adipose Tissue Modulations.” Or page 75 of Dr. Fung’s excellent book “The Complete Guide To Fasting”. As a side note I have been fasting for a few months for 36-48 hours at a time and have maintained muscle mass while losing fat and have not been exercising."
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nsflfk | Why is it so hard to tap your head and rub your stomach simultaneously but we use both hands to complex actions all the time with ease? | I never understood why it is hard to rub your stomach and tap your head at the same time. It's like you get so confused but we can grab two things at the same time or rub a desk and tap it with no problem. It's like there's a force field around our body. | Biology | explainlikeimfive | {
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"Muscle memory. If you practice tapping your head and rubbing your stomach at the same time you'll eventually be able to it just as easily as any other task that involves two complex actions at the same time (like typing this response). It's just that there's basically zero reason to ever practice tapping your head and rubbing your stomach at the same time, other than to get good at it to screw with questions like this one, so it's reliably an action you can pick that \"nobody\" can do well because they haven't developed the muscle memory for it. It's approximately the same reason the Vulcan hand symbol from Star Trek is amusing...nobody except Trekkies bothers to develop the muscle memory. Those that do can do it just as easily as the rest of us flip the middle finger."
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nsfm82 | Why frozen food smells way less, almost nothing, than when at ambient temperature? | Chemistry | explainlikeimfive | {
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"A lower temperature means molecules have less energy and are moving less. When you smell things, that's molecules of those things getting into your nose and attaching to smell receptors. So when something is frozen, those molecules aren't moving around much and not many of them are getting into your nose. When it warms up, those molecules are moving more so more of them make their way into your nose, so you smell it more."
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nsfn5p | How do nuclear weapons work? How do chemicals or a weapon the size of a room destroy countries? | Chemistry | explainlikeimfive | {
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"The actual nuclear warhead is a lot smaller than the size of a room (the whole rocket is not a weapon, just the explosive part at the end). Additionally, a *single* one is nowhere near powerful enough to \"destroy a country\", unless that country is like the Vatican City or something > _ > And it's physics. There's a ton of energy bottled up in these unstable elements like Uranium or Plutonium. They are excited and on edge ready to shed some of that energy in order to reach a stable state. When you hit them with neutrons that are moving at the right speed, it's like breaking the balls on the first strike with a cue ball in pool. Or hitting a group of pins in bowling. They break up into smaller atoms *and* shoot out other particles, including more neutrons. Those neutrons hit other Uranium or Plutonium atoms which do the same thing, and you wind up with a chain reaction that releases as much of that potential energy as possible."
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nsfrdf | What does Data Roaming do? | Does it increase data speed? Should I have it on or off? | Technology | explainlikeimfive | {
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"Data roaming allows you to have a data connection when you're not on your \"home network\". For example, if your contract is with AT & T in the US, if you're on AT & T's network you're not roaming, if you're on anyone else's network (typically in other countries) you're roaming. Roaming data charges can be \\*very\\* high (like thousands of dollars per month) so most phones have the option to turn data roaming off. You should generally leave it off unless you're sure that your plan covers data roaming and/or you want to pay the potentially very large bill.",
"By default, your phone connects to the cell tower that is owned by your cell phone service provider (AT & T, Verizon, T-Mobile, Cricket, etc.). And, it is constantly trying to connect to a cell tower to make sure you have service, as long as you're not on Wi-Fi or airplane mode. Now, with Data Roaming *off*, your phone will *only* connect to cell towers that it is authorized to according to your subscription plan. So if you're a T-Mobile customers, it will only connect to T-Mobile towers, or towers related to a T-Mobile service. With Data Roaming *on*, your phone will *try* to connect to a T-Mobile tower first, but if it can't find one, it will connect to whatever else it can find to ensure you've got a steady connection. This is great if you're outside your normal service provider's area of coverage, *but* it can also cost you extra for data, phone and messaging fees when you're on the other provider's tower. How much you owe, if anything, will depend on the terms of your plan. As far as having it on or off... Really just recommend keeping it off if you have good coverage with your phone, unless you've got some magical contract that makes it free :\\",
"Roaming in this context is the act of using your phone in an area/country not covered by your provider. Within your home country, your phone works via the network provider that provides your contact. An AT & T phone connects through AT & T cell towers, and AT & T deal with everything. They only have the license to broadcast their signals in certain countries however. So if you travel into a country where your provider doesn't exist, your phone is now useless as there is no appropriate network available for you to connect to. This is where roaming comes into play - your network knows it is a useful feature to have your phone be able to work in multiple countries, so they have made agreements with the network providers available in various other countries to allow your phone to work - so instead of connecting to your usual network, your phone will connect to the local company that your network has an agreement with and still work. The issue is that this can come with a cost. Because you are not using your normal network, there can sometimes be additional charges to use your phone which can be pretty expensive. The option in your phone's settings to turn off days roaming means you can stop your phone from sending or downloading any data if it is not connected to your normal network, unless you specifically allow it - so you won't get a nasty surprise because your phone has been quietly downloading email in the background, running up a data bill that is being charged by the megabyte. Incidentally a lot of networks will have better agreements that will not cost you so much - European carriers for example I believe all have no roaming charges. So if you travel from Germany to Spain, you will connect to the local network, but will use your normal phone allowances and it won't cost you any extra. So if you are traveling, definitely check with your network to see what the rules and costs will be."
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nsfy7b | How do dinosaur bones stay in tact for millions of years? | Biology | explainlikeimfive | {
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"Bones of Dinosaurs and prehistoric animals are protected from rotting by layers of sediment. As its body decomposes all the fleshy parts wear away and only the hard parts, like bones, teeth, and horns, are left behind. Over millions of years, water in the nearby rocks surrounds these hard parts, and minerals in the water replace them, bit by bit.",
"They don't. They become fossilized. Once the organic bits rot away and the bone is surrounded by rock water slowly wears away the bone and minerals from the water take its place. It eventually forms a different kind of rock, but in the shape of the bone that used to be there. So when we dig them up we have the surrounding rock and a different rock in that shape: a fossil."
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nsgblc | why do screens look weird through cameras? | I would post an image of what I’m talking about but image posting is disabled. | Technology | explainlikeimfive | {
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"This is a phenomenon called a moire pattern. Basically, the pixels of the screen are misaligned with the scan that your digital camera performs. It doesn't happen with non digital cameras.",
"Because the screen doesn't have a constant picture, it's actually cycling through and blinking the pixels so fast that we just see a constant image. A camera takes a picture very fast (and sometimes not all at once) so your picture captures the screen as it's in the middle of going through pixels.",
"These are called Moire patterns. [They form when you overlap two patterns]( URL_0 ). Parts where both grids stick out appear to add together and form darker structures. Your digital camera has a grid of sensors that react to the incoming light, which is uses to determine pixel values. Your screen is also made of a grid of pixels. These grids usually don't align, so a Moire pattern forms."
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nshggg | How do sunflowers “know” which way the sun is facing? | Earth Science | explainlikeimfive | {
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"To know which way the sun is they have light sensitive proteins which detect the energy in the light from the sun. To face the sun, when the proteins detect the light they cause a series of chemical reactions in the stalk of the sunflower which moves water in and out of its cells to create pressure and tension stretch and bend the stalk towards the sun!"
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nsi1wf | What is "fresh air"? Is air not just air? | Earth Science | explainlikeimfive | {
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"text": [
"Air near human habitat, especially big industrial cities, has higher concentrations of co2, smoke, nitrogen oxides, smog etc. When we go away from it to the country or to a mountain, we sense (and smell) the difference and we call it fresh air",
"Also, if your locked up in a room, even a room thats recirculating air through an ac unit or the like, the air can start to feel “stale” or “stuffy”. This is when you have people saying “open the window and let in some fresh air” in which you are simply cycling out the old stuffy air with “fresh” air.",
"The concept of “fresh air” is a Victorian one. The Victorians were terrified of suffocating in their houses - even though studies have shown that their houses were far more draughty than our modern houses with our well-sealed doors and double-glazing and proper waterproofing, and modern houses experience a complete change in air every thirty minutes whether we want to or not. The general medical advice in the 1800s was to always leave at least one window open (regardless of weather) to allow “fresh air” to circulate and avoid suffocation. This was especially important for children. Fresh air has maintained its reputation for health benefits, but its meaning has changed slightly over 200 years. Now, it means “air without pollution” instead of “air containing oxygen.”"
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nsj55m | Why are refrigerator doors harder to open when they’ve just been closed? | Physics | explainlikeimfive | {
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"When the door is closed, the air inside cools. Air expands with heat and contracts when cooled. The fridge door is not a perfect airtight seal. So the air pressure inside and outside will eventually equalize (as the air inside cools, warm air will slowly leak in and balance the pressure). So the first time you open the door, the inside and outside are at equal pressure (despite being different temperatures), and it's easy to open the door. When you open the door, all of the cold air \"falls\" out the bottom of the door (cool air being more dense, and therefore heavier, than warm air). This is replaced by warm air entering near the top of the door. When you close the door, you now have a mass of warm air in contact with the walls of the fridge and the items in the fridge. This causes a rapid cooling of the air, which makes it condense, which creates a vacuum inside the fridge. If you open it again soon enough, you must fight this negative pressure sucking the door closed. If you wait long enough, the door seals will leak enough air in to allow the pressure to equalize, and it becomes easier to open again."
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nsjp1y | Why aren't computer-viruses as common on cell phones as they are on PCs? | Technology | explainlikeimfive | {
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"There’s a few reasons. The first, and most obvious is that most software is installed through an App Store now which (in theory) vets the submitted code. Things do slip through, but it’s not as common now. However, the biggest element is that computers as a whole are just more secure now. Things like (good) virus detection being built into an OS standard and into web browsers, better practices (such as how Microsoft Office handles Macros), and other bits (Like MacOS’s ability to block non signed apps), just combine to make computers harder to infect for the average person. Of course the underlying code has been improved too. But, it’s important to note that viruses are a threat on mobiles.",
"They are really common on phones. Like terrifyingly so. There have been a lot of malware takedowns over the years on both the iOS store and the Play Store for apps that have been installed millions or tens of millions of times. You can also get malware installed from just browsing web pages. There have been cases where just receiving a text could install malware on your phone. The thing is that in pretty much all of these cases the malware is designed to hide itself. So you don't know it's there. They usually just want to track you. Sometimes they make you send spam texts. Or fake adclicks to a specific developer. Or mine crypto. Or just steal all your private data or bank accounts. Or just sit there waiting for instructions. And they usually go through insane lengths to stay hidden. Some have been mass installed by millions and only seemed to target a handful of people. This problem is WAY worse for devices that don't get security updates anymore. As in the absolutely mind boggling number of old Android devices out there that haven't received any security patches for years. Most of the users of these devices don't even know they've been compromised because at the end of the day most of the malware wants to stay hidden as much as possible.",
"Frankly, I think it's because of Windows. Android and iOS devices run on Linux/UNIX. These operating systems are much, much more secure than Windows. Windows still runs on some very old code that was originally written in the 80s and 90s. To this day, there are ways of breaking into Windows systems that haven't been addressed for decades. For example, when booting into safe mode, it is possible to replace the on-screen keyboard app with a copy of Command Prompt in Windows' files. When you boot the machine normally, you can access the \"on-screen keyboard\" without logging in. Now that you've replaced it with Command Prompt, you have direct access to enable the default administrator account and get in without ever cracking the owner's account. This method of bypassing Windows security has existed for as long as I can remember. It's shockingly bad."
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nsk0rk | Why do your joints ache when you have the flu? | Biology | explainlikeimfive | {
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"Tissues in the joints tend to inflame when you're sick. Those inflamed tissues are now under more pressure than they should be, which causes the pain. The inflammation is a side effect of proteins our white blood cells produce in order to fight infection. Our own tissue also reacts somewhat negatively to it.",
"When your body has an infection, the white blood cells need to gain access to the infected areas. Many white blood cells will be circulating in the blood and will need to leave the blood vessels to get into the tissues where the virus/pathogen is located. This is called extravasation. The blood vessels themselves are made of cells that are lined up side by side. During extravasation, the white blood cells will send signals telling these vascular cells to stand apart (leave space between them) so that the WBCs can get through more easily. This has the good effect that the WBCs can get where they need to go but the disadvantage is that fluid from the blood also leaks out. This fluid can cause swelling and puts pressure on the tissues causing pain."
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nsk4u2 | What does solder actually do in electronics? | I understand that part of it is for structural support, but what else is it for? | Technology | explainlikeimfive | {
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"It is basically just conductive glue. It holds electrical components in place and allows them to conduct electricity along a path between them and the next components in the circuit.",
"It’s a means of connecting wires to wires, or wires to circuit board, which means energy/data needs to be passed through it. It is structural - but also conductive; meaning any electronic signals can still pass through solder and into whatever the solder is connected to."
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nskzs6 | Why do we most often feel disgusted/uncomfortable when scratching certain materials? (Wood, chalk, etc.) | Biology | explainlikeimfive | {
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"text": [
"It's the same feeling we get when people shriek at the same frequencies. It's part of our fight or flight system that gets engaged."
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nslaca | Why does room temperature water give the sensation that it is cooler than room temperature air? | If I leave a glass of water on my nightstand overnight and drink it the next morning, the temperature feels notably cooler than that of the air surrounding me. What causes this sensation? | Biology | explainlikeimfive | {
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"We don't sense the absolute temperature of our surroundings. We sense the temperature of our own surface tissues and the rate at which it's changing. Our bodies are constantly generating heat and dumping it into the environment. Our skin exists at the boundary between the warm body and the cool environment, and its temperature is somewhere in between the two, dependent on the rate that heat is flowing. Water is approximately 1000 times denser than air, and has a much greater ability to absorb heat. Since water can carry away body heat much quicker than air, it causes the temperature of our skin to drop, which causes us to perceive that the water is cooler.",
"Worth noting that on top of the fact that what we feel isn't temperature, which has already been mentioned, water is almost always actually cooler than the air. This is because water constantly evaporates, and another way to think of evaporation is the fastest particles in the liquid jumping out of the liquid and becoming gas. This overall cools the liquid because only the high energy molecules can leave, leaving water constantly being cooled until its fully evaporated. Same reason why sweating works. This causes the water to come to an equilibrium between the evaporative effect and the effect of normal heat transfer from the table/cup to the liquid. That equilibrium is lower than the actual average temperature in the room."
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nsmpma | why when flying, do we have to have our seat in the upright position if it’s only an inch difference? | Other | explainlikeimfive | {
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"Safety - not just for you, but for the people behind you. For you, your lap-belt may not (but probably will) work as effectively if you're leaning back than if you're sitting straight up. The force of any impact would cause your body to move forward, and if you're leaning back, your upper body has further to travel (and get up to a higher speed) before the belt stops you. This is why in the brace position, you're told to lean forward. For the people behind you, by having your seat leaning back you're reducing the amount of space in front of them (which stops them effectively taking the best bracing position) and putting a barrier in their way.",
"In the event that you have to evacuate the plane, it is easier to get out if the seat in front of you is not reclined.",
"The seat in an upright position is in it's most forward position, it becomes physically harder to move seat forward anymore than it already is. If you were to impact in a reclined seat it would be much easier for the seat to catapult you forward or worse collapse on you. In addition in an impact situation the upper seat moving forward or collapsing would put additional strain on the seating anchors; possibly allowing the whole bench to break free and move throughout the aircraft freely."
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nsmzl1 | How do cheeses get their different tastes? | It’s my understanding that most cheese starts out as milk, then boiled for curds, then salt is added, and they’re aged. However, we know the difference in taste between cheddar cheese and Gouda cheese, for example. Where does this taste difference come from? | Other | explainlikeimfive | {
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"Well for starters, there are many different animals whose milk we use to make cheese. Cheese made from cow's milk tastes very different from cheese made from goat's milk. Even the diet of the animal influences the taste. Beyond that, you pasteurize or not pasteurize the milk, change the consistency of the curds, add different amounts of enzymes, have different amounts of moisture, use different strains of bacteria, and age the cheese in different conditions for different lengths of time. All of these factors will produce cheese with wildly different textures, consistencies, aromas, and flavors.",
"Things that affect the flavor of cheese: * the kind of milk you use (cow, goat, sheep, buffalo) * what that animal was eating when it produced the milk * how much fat is in the milk * what type of bacteria or mold culture you add (that's what turns the cheese into cheese) * how long the cheese is allowed to age There's a lot of possible combinations and that's why there are so many types of cheese."
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nsn7xt | The light of the sun takes 8 mins 20 seconds on average to reach earth, would the consequences of death of the sun be felt after that 8mins or would they be felt immediately. | By consequences I mean: the effect of the sun on the life on earth, E.G: heating of the earth & #x200B; \*I know that we would witness the death of the sun 8min20sec after its death (because everything we see is from a past whether distant or close \[stars vs object thats getting moved\]) & #x200B; WOuld gladly add specification to the question if necessary. | Physics | explainlikeimfive | {
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"All of the results of an event are limited to traveling at c. If the sun straight-up vanished tomorrow, it would take 8:20 for our planet to no longer feel its gravity. To no longer experience its light, or the heat carried by its light.",
"It would take that 8 minutes for us to realize anything has occurred. The light itself, the heat that the light creates, as well as the gravitational force all travel at light speed. Nothing travels faster than light, including all forms of information.",
"No effect travels faster than the speed of light. Even gravity propagates at the speed of light. So there will be no effects noticed on earth until at least 8 min 20 seconds.",
"The heat we get from the sun is the light. They’re the same thing. Not all of it is visible light, but it’s still just different frequencies of light. So all of the light, and therefor the heat as well, that was emitted from the sun would continue to hit us for 8 minutes before we’d see it go out. The other effects would be things like gravity. So if the sun just disappeared or something the planet wouldn’t be able to orbit around it. But gravity ‘moves’ at light speed too. So we’d see the light disappear at the same time the gravity would fade and send the planet flying off into the void."
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nsnf7q | What exactly happens in the body that causes it to feel instantly better or “quenched” the second you drink water when you’re thirsty? | Biology | explainlikeimfive | {
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"When you're dehydrated, the mucus membranes in your mouth and esophagus dry out Drinking water moistens the mucus membranes, which send signals to your brain that you are no longer in danger of dehydration"
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nsnu0d | How does the newly required vertical 911 location work? | I can understand how cell tower can triangulate using x and y coordinates, but how does the tower know z? I would have thought that would be something the phone would do but it's apparently on the carriers. How the heck does that work? | Technology | explainlikeimfive | {
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"Carriers could already use GPS as a reference point for altitude if there were four or more satellite signals reaching the phone. To further enhance location accuracy, your phone has a barometric pressure reader. Pressure changes with elevation (this is also one of the sensors fitbits use to determine floors climbed for the day). & #x200B; Readings can be pulled from this sensor and combined with the GPS / tower triangulation data to get within a 3 meter vertical reference point for the caller. The carrier requirement wasn't to develop an entirely new z-axis technology, but rather to refine the accuracy of the measurements and send the results over the e911 system. & #x200B; ELI5: Your phone already knows your rough elevation, so all carriers have to do is grab that info from your phone and send it to the 911 center."
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nso2ni | Why Ceramic Spacer would break after ISO alcohol applied(and dried) but not before. | Why would a ceramic spacer break in half when put to a butane/propane torch after having being drenched in ISO alcohol(and dried off thoroughly) when it normally would be able to deal with those heats? | Chemistry | explainlikeimfive | {
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"Is the ceramic glazed? If not then it would be porous, this will lead to the alcohol being absorbed into the ceramic and when heated it cant escape easily and will boil putting massive amounts of stress into its internal structure. Similarly when i was in the scouts a favourite trick of mine when i was in charge of building the fire we used to sit around in the evenings i would put a damp cinder block into the middle of it then build the fire around it, it took a few hours but it would break in two with a loud cracking noise as the water in it got hot enough to make steam and blow itself apart. It used to make everyone jump and i found it hilarious, no harm done."
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nspqba | Why do fingerprints stay the same despite pressure and stress throughout our lives | Biology | explainlikeimfive | {
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"The outermost layer of your skin is primarily dead cells. It's a very thin but very effective plating of armor that is constantly getting worn away by the environment, but it's getting replaced from underneath just as fast as it wears away, if not faster. Those dead cells keep growing into the same paterns (AKA your fingerprints) because they're growing in the same pattern as the deeper layers of your skin. That underlying skin stays relatively unchanged since the outer layers protect it. If you manage to damage these layers from severe burns, corrosive chemical exposure, or deep flesh wounding, you *can* permanently alter or even destroy your fingerprints. But common activities practically never make it past the outer layer, so in most situations fingerprints will always grow in the same pattern across your entire life.",
"Had a guy at work who polished/regrained metal stuff with wire wool for years as part of his job, I ended up giving him a fob to get in the doors as he had absolutely no fingerprints whatsoever and that was with a reader at max sensitivity as well.",
"Just to elaborate on the other answer, it's the dermal layer of skin that contains the blueprint. The epidermis is the part you see and the \"dead skin\" which gets old and wrinkly. There are changes with time to skin flexibility but the blueprint remains the same",
"It was my understanding that fingerprints actually don’t stay the same because of the reasons you stated. They actually do change a bit, so often times you do need to get reprinted. Also the reasons scanners eventually don’t work.",
"My finger tips were burned when I was a child and I tried picking up a hot pie dish. Going through LAX airport is fun on an international trip. Takes ages for the machine to go green on all 5 finger tips. I get lots of questions",
"I used to work for a company that installed fingerprint readers in hospitals. Part of my job was walking hundreds of nurses through putting their finger or thumb down on the reader and associating it with their login ID. Most nurses in their 30s and older had such smooth fingerprints from repeated hand washing that that their prints could not be recognized by the reader. Thumb prints were less likely to be unreadable so we could often use those.",
"I nearly successfully guilltoned my finger, and my fingerprint was altered with the injury, certainly. It was a bad injury. Permanent nail bed damage on the other side too. Despite all, the original fingerprint has made some of its way back after about 5 years, which I was amazed at. Where it was really bad, my print is definitely going to stay altered. But it's trying to be normal as best as it can.",
"I’ve worked as a fingerprint scanner technician, that’s a great question! The simple answer is they don’t. We can always tell if someone does a job with their hands for example because the fingerprint scans have the remains of many cuts and scars. What stays the same is the general pattern of ridges along your fingers, and fingerprint scans have some margin for error to account for exactly what you’re asking about.",
"Fun fact: you also have palm prints. There is a correlation between the distance of “whorls” (where the lines swirl together) in palm prints and psychopathy. Source: worked for a twin study in a university psychology lab and took palm prints to study said correlation. It was one of many things we recorded/tested."
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nsr42o | Why is it that I'm losing weight when I'm eating more? | Biology | explainlikeimfive | {
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"There can be a few reasons! Foods contain water and can help hydrate you. When you’re hydrated on a regular basis your body tends to drop it’s ‘water weight’. When you are not hydrated regularly your body thinks ‘fuck, this person isn’t giving me enough water - I better keep some spared just in case of emergency’. Also, when you don’t eat enough food regularly your body will purposely slow down its metabolism in order to reduce the chances of entering a state of atrophy (muscle wasting). It does this because if your metabolism is too high while you’re calories are too low, there’s a big energy imbalance so the body will try to protect itself. Another reason could be you’re not actually eating more, you’re just eating more frequently, but less/same calories but you’re full for longer and won’t feel the need for ‘unhealthy’ snacking. For example, someone who eats some cereal, a doughnut for lunch and a regular dinner may be eating say 2000 calories because the cereal is high is calories and the doughnut is 500-600 calories which is a lot for a very small, not-so-energy-efficient meal. However change your diet to a ‘healthier’ cereal (more energy efficient) and your lunch to a similar calorie but more filling and have small snacks in between each meal you may be eating the same or even more, but your meals are bigger therefore you think you’re eating me because well, your having more nutritious, hunger satisfying meals. I know you said you were eating 1300kcal per day, this example above is for other people who may wonder why eating ‘more’ (larger frequency, similar calorie) is helping them lose weight. Hope this helps!",
"A higher calorie intake will not cause you to lose fat faster. It's almost entirely calories in Vs calories out. So all else being equal, eating less loses fat faster. However, over short timescales there can be fluctuations.. especially water weight. Your weight can easily go up or down 2-4lbs a day based entirely on how much water you're drinking. And remember theres water in your food, and carbs tend to help your body store more water too. There is also some nuance in whether you're losing fat, losing muscle, and/or gaining muscle. That can blur the lines a little. But the effect is usually much smaller than the impact of a good diet over long term or water weight over short term. I would question your trainer's advice. What they're saying doesn't make sense, so there may have been some more nuance in there that's been missed"
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nsrbnn | I seriously can’t wrap my head around the idea of “time is relative”. | I just don’t get how time is faster and slower on planets that aren’t Earth and how this affects how we age as well. | Physics | explainlikeimfive | {
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"Time being relative is a byproduct of the fact that the speed of light in a vacuum is a constant regardless of your frame of reference. That probably sounded science-jargony and didn't help, so let's take a step back and talk about velocity/speed and frames of reference. There's a classic physics thought experiment where you have a truck going down the highway at 55 miles per hour, and in the back of the truck is an athlete or robot or something that can throw an object out of the back of the truck at 55 miles per hour going the other direction. From the frame of reference of the truck, the ball will be going backwards at 55 miles per hour (because the robot/pitcher/whatever and ball were stationary from the reference point of the truck), but if you're looking at this from the side, the ball will seem to stay right where it was released, because the imparted force that accelerates the ball to 55 miles per hour backwards is exactly cancelling out the forward velocity (from earth's reference frame) that was bestowed onto it by the truck. Now here's the next part of the trick, and where our intuition fails us: *Light in a vacuum moves at the same speed no matter what you're doing around it.* Let's take our truck and turn it into a rocket that can move at a significant percentage of the speed of light. And let's replace our ball-throwing person/robot and replace it with a flashlight. If this behaved the same way that the ball did, if we took our rocket and accelerated it to 0.5c (or half the speed of light) and from the reference frame of the earth looked at the light from the flashlight (it's a really bright flashlight), it would appear to be moving at 0.5 c as well (since it would be moving at 1c but would have to negate the 0.5c the ship was moving at), but we've tested this and despite it making no intuitive sense, *the light from the back of the rocket will be traveling at 1c (or just c)*. Similarly, if we take the flashlight on that same rocket and point it towards the front, and we take our intuition from the ball experiment, we might expect that light to be going at 1.5c, but it, too, will be going at 1c *no matter where we measure it from.* The ship sees it going at 1c, Earth sees it moving at 1c, Mars sees it moving at 1c... you get the picture. This is a case of *special relativity* - where velocity will cause time dilation and an increase in mass, weirdly. This is true of all velocities, but it's only really significant once you get closer to the speed of light. As for gravity, it's the same basic idea; the gravitational force should accelerate anything towards its center of mass, but since light's speed is constant, time in the local area gets distorted by the gravity. And as weird and alien as this all seems, we've managed to prove this experimentally using nuclear clocks and fast planes. Perfectly synchronized nuclear clocks, one left stationary at sea level and one put into a plane and flown around at a high speed by our standards but low speeds by light's standards, desynchronized as much as Einstein's equations predicted they would in those conditions.",
"Think of it as velocity. Lets pretend you are sitting in a car, the car doesnt make any sound or bumps or anything. Its like the car is not there. When that car is moving you dont feel that. In your experience, you are sitting still. On the outside there is a person who is standing still waiting to cross an intersection. When you approach that person it looks to you like that person is heading towards you, because in your experience you are sitting still. But to the person on the intersection it looks like you are heading toward them. From their perspective they are still. This is relativity in velocity. You both experience the other moving, because relative to eachother you are moving at different velocities. But both of you are also experiencing no movment from your own point of view. You experience your velocity as usual, its everyone else who is moving faster or slower. It is the same thing with relativity in time. You always experience one second as one second, but when you look at other people it will look like their time is passing slower or faster. So other people will look like they move in slow-motion or fastforward, because you are comparing them to your own experience of time. So 1 second for you, might be 10 seconds for someone else. So it looks like they are in slowmotion. But from their perspective, 1 second for them is 0.1 seconds for you, so it looks like you are moving in fast forward.",
"The best way to understand this is to look up some videos on the light clock example. You have a ball bouncing up and down between two plates. Each time it returns to the lower plate is one cycle. It's on a cart. If the cart is stationary and you are watching from the side you just see the ball go up and down. The path of the ball is a vertical line | and the lenth is L Now the cart starts moving sideways. From where you are watching, the path of the ball forms a triangle /\\ The vertical length traveled is still the same, L, but the path the ball takes, h, / is longer than L due to geometry (Pythagorean Theorem) You can draw a triangle and confirm this with a ruler. So with the cart moving, the ball takes a longer path. We have one of two options to consider now. From your stationary perspective, the ball can either continue to hit the two plates at the same rate it did when the cart wasn't moving, in which case it would have to travel faster because it is now taking a longer path. Or it can travel at the same speed along the longer path as it did along the vertical path, in which case, from your perspective, it would now be traveling slower vertically and would take longer to hit the plates from your perspective. Light cannot travel faster that light speed so if the ball is replaced with a photon, it chooses the second option. It travels at fixed speed along the path it takes and from your stationary perspective, as the cart moves by, the clock appears to move slower. To a person on the moving cart though, the photon still is only moving up and down and appears to do so at the same rate as when the cart was stationary. Everything on the moving cart appears to be moving in slow motion as you watch it go by. Everything the cart passes appears to be moving in slow motion to the person on the cart for the same reason. But everything off the cart looks normal to you and everything on the cart looks normal to the person on the cart. Edit: I just wanted to add a more intuitive understanding. Most people are familiar with scenes in movies where the person can move unusually fast (The Matrix, Quick Silver in X-Men and other movies/shows) and from their perspective the rest of the scene is in slow motion. It's similar to that if we say they are the observer."
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nss40q | How do currency mints know how much cash to produce based on monetary policy and how much cash is available? | Let's say there is a cash shortage because people are hoarding cash overseas or on the black market, how does the mint predict how much should be produced without flushing the country with cash? Am I looking at it the wrong way? | Economics | explainlikeimfive | {
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"Quick answer? They don't know how much cash to produce, generally speaking. I'm going to explain this process respective to the United States, as other countries, while generally utilizing the same system, take different approaches. First off, the United States Mint only produces coins, not printed bills. That is the job of the Bureau of Engraving and Printing (BEP). Both of these bureaus fall under the United States Treasury, a cabinet-level department. The Federal Reserve, our central bank, immediately receives printed cash and produced coinage, and stores it in one of the 12 nationwide locations. From there, private banks and lenders request \"hard cash\" from the Federal Reserve as public demand for tangible cash goes up (generally around the holidays). Conversely, when the demand for tangible cash goes down, banks and lenders tend to return excess amounts of on-site cash back to their accounts at the Fed. As for the people \"hoarding cash overseas\", the United States Treasury (specifically the Internal Revenue Service) tracks all cash stored overseas by US citizens and nationals. You can thank the Foreign Account Tax Compliance Act (FATCA/2010) for that. The FATCA requires US citizens and/or their banks to reveal their foreign assets to the IRS. This information ultimately assists the Treasury in calculating the tentative amount of hard cash to produce. Now, obviously there are loopholes and illegal activity (black market operations as you mentioned) that obscure this calculation, however, this number is somewhat negligible to Treasury Dept. calculators and policy-makers. Additionally, the Fed and Treasury allow a small percentage of cash to their calculations for any +/-. The government has invoked numerous mitigations to ensure the proper amount of cash is fluctuated and deducted, despite illegal activities and overseas dealings. FATCA was just one example. This same explanation goes for damaged/destroyed tender, which is suppose to be reported immediately to the Treasury, but is often not.",
"Frankly, cash and coins are a tiny fraction of the money out there. Balances on bank accounts - personal and corporate - are much easier to track and much easier to manipulate. The Federal Reserve manages monetary policy electronically by changing the interest rates it pays/charges banks and by buying and selling bonds, again almost always electronically through these bank accounts. cnmi02's answer covers the \"how much cash is available\" part of your question."
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nssdly | How can a tiny spider body hold so much silk? | Or do they make it as they need/shoot it? If so, how do they have enough material/ingredients for it constantly? | Biology | explainlikeimfive | {
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"It's a liquid when inside them. Also, it's so thin that if you condensed a whole web down the overall volume would be tiny.",
"Also, have you ever had one of those colds where you just produce a neverending stream of snot? Like a near tidal supply of grim goblins? Mother nature's got some loot bag steez man. A spider's webbing is a cinch."
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nssh6w | Why is problematic to have enlarged heart? | If heart is the muscle, then why having bigger and stronger muscle is not beneficial?. Especially for something as hard as pumping blood. But my doctor insist that i should be careful and not strain too hard. | Biology | explainlikeimfive | {
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"Not a doctor but from what I remember whilst the heart is enlarged it hasn't gained much mass so the chambers may be bigger the walls are thinner and thus may rupture more easily. If I'm wrong then feel free to correct me.",
"Your heart enlargened because it already is harder for your heart to pump blood and it needed more muscle to do the job. The bigger your heart is, the worse it gets at the job and it hinders itself, so you want to prevent further growth, or risk heart failure and death. So your heart grew to compensate for things like increased blood pressure or something else, but now it has to work harder, because the heart chamber is a bit bigger and the increased mass of the heart itself has become a problem. Were you to put additional strain on your heart by doing sports or other activities it would need to grow even more, potentially killing you in the process."
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nsshqi | What are linear equations used for? | Mathematics | explainlikeimfive | {
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"Loads of things. Take, for example, a taxi. Taxis charge a certain amount of money for every mile you go, plus some initial fee. We can write this as P=r•D+c, where P is the total price, r is the rate per mile, D is the distance, and c is the initial cost. We can then plot a graph of P against D and work out how the price changes as you go along. Now, say there is another taxi firm that charges a different rate and initial cost. You could plot *that* one on the same graph, and see which is cheaper for a given distance, or work out at what point they are equal. This is perhaps a silly example, but there are so many things that use linear equations. If you're going at a constant speed, then distance vs time is linear. Or a constant acceleration, speed vs time is linear. The amount of force to stretch a spring to a given distance is linear. And these are just a few things.",
"Everything. Linear equations turn into linear algebra, which has applications in pretty much every single field you can imagine. For example, in computer science we have: Machine learning, Google's page rank algorithm, storing data in a computer, building models of networks, etc. Linear algebra is up there with calculus as the most practical areas of mathematics.",
"Like any equation, it's a foundation for helping explain/predict a phenomenon you care about by building a model. Not all relationships between variables are linear, but we like linear because it's easy. A simple example would be in a laboratory. Suppose you have a sample that contains something you care about (compound X) but you have no idea how much it contains. In chemistry, it's a common practice to build a calibration curve based on samples with known concentrations of compounds you're looking for. Calibration curves are often linear, that is, the relationship between signal in the instrument and concentration of the compound form a straight line when plotted. What this allows the analyst to do is build a model that can be used to calculate the concentration of the unknown. If my calibration curve says a known concentration of 10 for compound X gives an instrument reading of 10, and 5 gives 5, 0 gives 0, etc., we say that relationship is linear because it has an equation of y=x, which forms a straight line, and proportionally changes together. So, when you know this relationship, and you analyze your sample of unknown compound X concentration, and let's say it gives a value of 3 in the instrument, you now can use your equation to say the concentration of compound X in my sample must be 3, and you rejoice because you just did great science."
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nssn34 | Why does skin peel like tissue paper after sun burn? Does it only happen on humans? | Biology | explainlikeimfive | {
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"The top layer of skin is killed from UV damage and the followup repair response (badly damaged cells will kill themselves on purpose to avoid becoming cancerous) and eventually separates from the living layers underneath. Most animals are more resistant to sun damage thanks to fur, feathers, or scales that better shield their skin from the sun. Those that are not can definitely suffer the same sort of injury with the same results.",
"Humans are really unique in that we don’t have anything covering our skin. Most species have hair or feathers or are underwater. Species like hippo can suffer the same damage but they also spend almost all day in water as a way to defend themselves from the sun."
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