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[ "It would be a waste of resources. When you are using fine motor skills one hand at a time is sufficient for most tasks. There is very little to gain from being able to use your hands equally well. So the ability to use both was never selected for as their were other uses for that brain power." ]

[ "Trying to collect some memory...\n\nCPUs can switch from powersaving to full usage in microseconds. The task of the VRM is to provide stable voltage to the CPU under extremely fast and huge changes of the CPU's power requirements, by storing electric energy in very large capacitors. VRMs are rarely components of their own any more, they moved back to the mainboard or are part of a CPU module.\n\nLow-power CPUs may settle with the output of power supply or a battery." ]

[ "Warning: technical subject, so writing this in some very ELI5 form is quite hard. This is more like ELI beginner programmer. To tell if you need anything clarified.\n\nOn Linux:\n\n* Shared memory. Two processes have access to the same block of of memory. Can be done with SysV shared memory with shmget, or mmap + fork\n* Sockets. You can use UNIX sockets, or an actual TCP socket with one process listening on some random port on localhost and another connecting to it. This can be set up with socketpair() + fork()\n* memfd. A memfd is a Linux specific mechanism where you can create a virtual file that can be written to, and the memory then transparently appears readable to another process in such a way that there's no copying going on, but the original sender can't mess with the message while the reader is reading it.\n* Pipes. Pipes are directional, so if you want back and forth communication you want two: one for A to B, and another for B to A.\n* Signals. They allow you to poke another process, basically. No actual data is transmitted only \"Event happened\". Mostly useful for things like \"hey, reload your config file\".\n* Temporary files. You can just write some data somewhere, and have another program read it.\n* Protocols built on the above. For instance, DBus works over UNIX sockets, and adds structure on top of that.", "The most common way to implement IPC are using pipes, named pipes, message queues, shared memory, and sockets. Linux and windows use all of these. \nThe OS almost always handles the process communication so that the user almost never has to deal with it. \nAs for sending the message it depends on the type of message and it’s importance. Some that don’t need to be acted on immediately are sent via message queue, think snail mail. Others that are super important will be sent via a pipe or socket, think instant message. Shared memory messages are like you and you friend watching tv and you both have a remote that changes the channel, You can change the channel at anytime and you both instantly know. \n\nMost processes can communicate multiple ways. They do this so that other processes can easily send info when needed, the same way most people have a phone number, email, text message, instant message and so on and what not. \n\nThis is the basics, there is a ton that is glossed over and much computer jargon that has been simply ignored, but the jist is still there." ]

[ "It started on [2channel](_URL_0_). The culture and large audience of this text-only site led its denizens to go looking for characters to make pictures from, first [the Shift JIS character set](_URL_1_), but then later the whole Unicode character set.\n\nJust like on Reddit, text that looks like a picture stands out and brings in praise, and the community want to one-up it or continue with pictures to make a story.\n\nWestern bulletin boards, message boards, USENET had already been doing the same since the 1980s with ASCII art and ANSI art.\n\n4chan copied what they saw on 2ch and brought their ideas to English-speaking sites. However, their Japanese origin might make them seem niche or undesirable (e.g. for weebs only)\n\nI suspect most people who repeat these little faces store them in a text file so they can copy-and-paste them on demand.", "As a non-japanese person with a basic understanding of the japanese language:\n\nBecause Japanese uses the chinese characters (of which there are many thousands) they just have a autocomplete-like feature where they enter a word in one of their syllabaries (hiragana and katakana) and can choose from a list of possible characters based on their input.\n\nThe Japanese simply added those multi-character faces to the list of possibilities they can select from." ]

[ "Pls link to \"all that talk\". First bit: A bullet fired down would not actually go to Earth due to orbital mechanics - it would actually be best to fire the bullet backwards from the orbit. Now: bullets falling from orbit would just disintegrate unless they were very specially designed. They would likely have to be quite large - more like mortar shells than bullets. These bullets would also have to be fired at very high speeds, since they would have to deorbit themselves in order to reach Earth and orbit is really fast. Lastly, these bullets would have a lot of recoil and the satellite would have to use engines to counteract the recoil. It would ultimately be easier to use missiles instead of bullets and skip those steps. When and if these projectiles did strike Earth, their damage would scale with their size. Anything from a grenade-sized boom from a small bullet to a small nuclear-sized explosion from a telephone-pole-sized tungsten rod-from-god.", "It would hit (or come close to hitting) the gun that fired it.\n\nBecause orbits work by having something move sideways so quickly that you miss the parent body as you fall. This means that, in order to de-orbit, you need to accellerate retrograde (slow down along the orbit) rather than radially in. By accellerating radial in, all you do is slightly shift the orbit and make it elliptical.\n\nScott Manley does a good job explaining it visually in [this video](_URL_0_)", "Nothing special. The bullets would likely fragment upon reentry, but even if they didn't they would slow to terminal velocity before reaching the ground and wouldn't be lethal. Also you would never hit anything at that range so it would be pointless." ]

[ "The pharmacies pay for inclusion in the app/site's listings. They also pay a portion of the discount to GoodRx.", "The pharmacy pays goodrx a portion of the transaction total for accepting the discount card." ]

[ "The same way Bob Marley could sing that he shot the sheriff and \"get away with it.\"\n\nThey're just lyrics, and not descriptions of real events." ]

[ "plastics are generally made of synthetic polymers, which are molecules that are long chains of repeated units. They aren't natural materials in that the molecules that make them up don't occur in nature; they are created by chemical reactions, often a complex sequence of many different reactions, that usually start with crude oil." ]

[ "Wisdom teeth are vestigial. Which means that basically they are a hold over from the days when we used to need them to eat plants. Some people don't get wisdom teeth at all.\n\nThe issue with Wisdom Teeth is not the teeth themselves, but the fact that the jaw doesn't have sufficient space to support them and the teeth push against other teeth leading to impaction which causes issues with your gum tissue becoming inflamed and or infected.\n\nYou don't actually have to have them removed, although this is the most common form of treatment, sometimes you can have corrective surgery to put the tooth in the right place which allows you to keep your wisdom teeth.", "Well it's not like we grow them on purpose, it just happens naturally. Also they don't always have to be removed, they are removed only if they cause trouble.\n\nOur bodies simply haven't caught up. Human mouths became smaller than their evolutionary ancestors' mouths, but the wisdom teeth remained as a sort of vestigial organ." ]

[ "The somatosensory cortex is an area of the brain that contains a map of all your body parts. It has neurons that process the sensory info from your fingers, arms, legs, etc. When a body part is amputated, the area of neurons in the somatosensory cortex that correspond to the sensory info of the amputated part still exists and the brain can mistake for the amputated limb to still be there sometimes. It was found by some studies and now known as the mirror cure which can remove the occurrence of phantom pain.", "There's a theory that the nerves send pain signals to the brain to let it know that something is wrong with that limb, because they're no longer recieving signals from the (amputated) limb." ]

[ "Imagine there is a mountain, and you go around collecting a thousand different Rock samples from different parts of the mountain. All of those rocks samples vary a little bit, but all of them are more than 90% granite. At that point, provided your sampling was done well, you can reasonably conclude that the surface of the mountain is mostly granite.\n\nLikewise, meteorites fall to Earth all the time. Scientists have collected thousands upon thousands of them. And all of them fall within a fairly narrow range of composition, so we can reasonably can say that most meteors should fall within that range of composition. We cannot say with 100% certainty that there are not weird meteors composed of different things, but they are certainly in the minority.\n\nAnd a little note on your terminology: a meteorite by definition has already fallen to Earth, so we can analyze it. You should probably be talkin about meteors instead.", "Part of this is actually done by analyzing the light that the meteorite reflects back. You've probably heard before that different objects reflect some wavelengths of light and absorb others, and that's how we can see colours. At a more detailed level, you can analyze exactly which wavelengths were absorbed using a machine called a spectrometer. Using that data, we then look at what materials we know on Earth could produce the same absorption pattern, and that tells us what materials the meteorite is made of.", "When different elements burn they let off different light patterns. We can look at the patterns of light from an object and determine what it is made of. For more details look up spectral analysis." ]

[ "There are four answers to that and nobody is entirely correct saying any one of them. Depending on the materials you're gluing together and the glue itself it could be any combination of the four following theories.\n\nThe first theory is Adsorption. Basically that molecules in glue have a weak electrostatic attractive force that bonds glue to surface and glue to itself. The molecules in glue have weak magnetic force because some are positively charged and some are negatively charged. They seek out other molecules to bond with like a magnet and hold together.\n\nThe second theory is Chemisorption where the chemical structure of the glue and the thing it is on form a new type of chemical with strong chemical bonds. This commonly occurs when glue is applied to certain plastics.\n\nThe third theory is that the glue bonds Mechanically. The glue seeps into the cracks and holes of a porous or semi-porous surface of the two materials being bonded and dries as the glue in the middle does physically locking the surfaces in place.\n\nThe last theory is Molecular Diffusion. The molecules swap between the glue and the surfaces and equalize with each other causing molecules of glue and material to mix and form bonds." ]

[ "Some religions believe your body is the physical property of God. You are just borrowing it for your time on Earth and at the end when you die he gets it back. You're not allowed to damage it because it's not yours and a tattoo is damaging the skin.", "For hebratic religions is was often to make it clear who was a follower of who. It my understanding that many of the non-Jewish religions used tattoos as ritual markings and branding to show that they are devoted to a specific worship. Since the Hebrew God said have no other Gods before me, and demanded no markings, then one way to stay clearly separate from the other religions was to not have tattoos or body markings. \n\nA good chunk of the Hebrew law was for this reason, and as such many scholars feel like it is not longer relevant today.", "1 Corinthians 3: 16-17 (KJV Bible) says \"Know ye not that ye are the temple of God, and that the Spirit of God dwelleth in you? If any man defile the temple of God, him shall God destroy; for the temple of God is holy, which temple ye are”. \n\nSince our bodies are temples we should treat them with the utmost respect. Tattoos (and other things) are a disrespectful way to treat our bodies that God gave us.", "because religion is a method of control. and therefore restricting what people can do / eat etc. helps maintain a grip on the populace. in Catholicism the act of confession was less about confessing your sins and more to do with placing the priest in a position of power by knowing the naughty things you did. giving him the power over the congregation by being able to remind them he knows there darkest thoughts.", "Tattoos have been used by some religions to mark the bearer as dedicated to a god, and in so doing request the deity's protection as a bearer of the god's markings. In that case, religions that forbid the worship of false gods (Islam, Christianity, Judaism are the most common examples), often also forbid tattooing, so as to avoid behaviors that could lead to worshiping a false god." ]

[ "According to the FDA, the plastic used in water bottles is completely safe for repeated use. They do add that you should wash your plastic bottles because they could have bacteria in them that builds up after being refilled multiple times. Per the FDA, the original source of the rumor that plastic bottles being reused cause cancer was from an email hoax that went viral. That email hoax was based on a student's masters thesis and the thesis has not been peer reviewed.", "What unbiased agency is saying dangerous chemicals will leach into your water? What health authority is providing this information?\n\nThe main concern with refilling one-use-intended plastic bottles is sanitation, not chemical leaching. Once your lips touch the bottle or you crack the seal and air gets in, the odds increase that the \"pure\" water in there gets pathogens in it.\n\nPlastic one-use-intended bottles will slowly degrade over time, but not enough to cause chemical leachate into their water unless you keep them for years.", "The danger of reusing a single-use water bottle has nothing to do with the chemicals but everything to do with its shape. The problem is those ridges in the bottle which are there to make the bottle stronger while using less plastic overall. However, these ridges are excellent places for bacteria to get caught and grow. Once they grow enough, they can make a protective layer, called biofilm, that will protect them from soap and other chemical cleaners. Using a scouring brush to clean the bottle just makes it worse because it creates many tiny grooves for bacteria to get caught in. \n\nYou can reuse the bottle a few times, but you should toss it within a week at most of first drinking it.", "The bottlers don’t want you using the same bottle multiple times. Nestle would much rather people purchase their water repeatedly rather than refill one bottle multiple times.", "'Plastic contamination is rampant in bottled water. That was the unsettling conclusion of a study published last year in Frontiers in Chemistry that analyzed samples taken from 259 bottled waters sold in several countries and found that 93% of them contained “microplastic” synthetic polymer particles.'\n\nThe article goes on to say the World Health Organization is investigating the safety of bottled water. \n\nSource: _URL_0_\n\n(Opinion) We are interacting with these microplastics on a daily basis but directly consuming them seems foolish even without conclusive evidence of their effect on the body. At the very least they are foreign substances that the body has not evolved to process. \n\nOver time we have been able to identify many things as harmful that were seemingly innocuous, like lead paint in children's toys. Just because something is legal and unregulated does not mean it is safe. Use your own discretion.", "**WARNING!** If you refill the water bottle with tap water, you dangerously risk the well being of capitalist businessman as they might not afford to buy a second yacht this year.\n\nA regular store bought water bottle contains 1% plastic, 0.001% water and 98.999% profit (in money terms)", "I think you are confusing 2 ideas about thin plastic. Single use water bottles are completely safe to refill in that concern as all the other comments mention. \n\nI believe you are thinking about heating food/drink inside thin plastic containers in a microwave for example. If the container does not specifically state it is microwave/dishwasher safe, then it cannot be guaranteed to not degrade at all or contaminate whatever it is holding.", "Is this an american thing? I've never heard the claim to never re-use water bottles.", "If it hasnt already leached into the water thats been sitting in that bottle for a few days / weeks, then it wont leech into the water when you refil it and leave that fresh water sitting for a few hours before you finish drinking it.", "Snopes has you covered\n\n_URL_1_\n\nAs has already been mentioned, it’s just the spread of false information. What is undetermined is the effect of heating those bottles on the liquid contained in it. But otherwise, you’re fine.", "It is not actually unsafe to reuse water bottles. That's a myth from the 90's. The plastic used in your water bottle is perfectly safe for repeated use (as long as you're washing it to remove bacteria like you would with any other container). Indeed, the bottles wouldn't be allowed to be sold if they could leech those dreaded \"chemicals\" into the water.\n\nPeople that sell water are certainly not going to go out of their way to dispute that myth, because (as you suspected) it results in people buying more water bottles.", "Are water bottles that got hot in the car and smell funky alright to drink?", "I was under the impression that refilling plastic bottles to be safe in itself, but you're not supposed to drink from them if you've left it in a hot car or something because it's the heat that makes the plastic leach chemicals into the water.", "I have seen that it is dangerous to leave them sitting in a hot car and then drinking from them, but that seems flawed. You would think that sometime during the transportation that they were kept in hot conditions before reaching the grocery store. Local news did a report a few years ago, about reusing bottles that you have kept in a hot car. Apparently they can also create a focused beam of light from the sun and potentially cause a fire in your car.", "This is a complicated question, and there's not really a solid answer on it one way or another! Can you tell us where you're hearing that these reports?\n\nWhat it comes down to is that scientists aren't sure one way or another whether plastic use, generally, is safe or not for storage of food and drink. It comes down to this idea of \"leaching\", and it's kind of a hot topic.\n\nThere's been a few studies done on it in the last decade that basically conclude, \"Well, we're not sure - we should look into it more!\"\n\nThere's a whole lot of debate in this thread about sources, so I've compiled a few of the more recent studies that have been done. I found these with a quick Google search and I've included an ELI5-appropriate summary for each one. :)\n\n[Synthetic Polymer Contamination in Bottled Water (2018)](_URL_5_)\nThis study tested just over 250 bottles worldwide, from _URL_4_ to Lebanon, and found that 93% had some kind of microplastic particles in them (from very small to reasonably small). The study concluded that the particles have to be at least partially coming from the packaging or manufacture process. They recommend more studies on the impact of microplastics on human health.\n\n[Most Plastic Products Release Estrogenic Chemicals: A Potential Health Problem That Can Be Solved (2011)](_URL_5_)\nThis study looked into whether plastic products, including ones advertised as BPA-free, released chemicals that had estrogenic activity (\"EA\") - a chemical that mimicks the estrogen hormone. They tested more than 500 products. They found that nearly all the products they tested released chemicals having some kind of EA, and some BPA-free products actually released more than their counterparts. They recommend changing the way we make plastic to remove the risk of EA leaching.\n\n[Migration of plasticizersphthalates, bisphenol A and alkylphenols from plastic containers and evaluation of risk (2012)](_URL_4_)\nThis study investigated whether or not plastic and additives can migrate into the water from bottles. It used three different ways of testing. BPA was found in all the water they tested in levels below the legal amount, but they warned that since people use different kinds of plastic through the day, they might be consuming more than they think. They remind that BPA has shown negative effects in animal experiments and that more study is needed on the long term effects on humans, and notes that BPA has been banned in Europe.", "What about a plastic water bottle in the sun? Does the plastic being out in the sun do anything to the water inside?", "The thinner plastic in the 'disposable' water bottles is more likely to break down *in heat*, than thick plastic you find in re-usable water bottles. That breaking down *can* cause plastic to mix or leech into the water. For example, leaving water in the car on a hot summer day or in direct sunlight can be like putting plastic in the oven. Bad idea! However, if the plastic hasn't been exposed to heat or a lot of wear and tear, then there's nothing causing plastic to break down and leech anywhere. \n\nAlso there's bacteria that all the other posts are talking about. Disposable water bottles are so wasteful anyways! Why not just get a reusable plastic that can take heat and go in the dishwasher. Better in every way except that you have to carry the bottle home (which you're doing in the re-use scenario anyways) and don't come filled with water.\n\n\nEdit: There's a lot of conflicting research, but it makes *a lot* of sense for thinner plastic that isn't dishwasher safe to not handle heat super well.", "Is it safe to heat a frozen burrito inside the plastic bag, per the directions? I’m needing an ELI5\n\nEdit: the same question applies to using any plastic in microwaves - plastic bowls/cups/dishes.", "I thought it was because bacteria built up on the mouthpiece and cap not that plastic would leach into the water." ]

[ "The deficit is the amount by which spending outpaced earnings.\n\nSo if the debt is 100k, and your deficit is 20k, now debt is 120k. As long as you have *any* deficit, the debt will go up.", "Because there was still a deficit.\n\nAny deficit means that your debt will grow; a smaller deficit just means that your debt grows more slowly. \n\nIf what confuses you is comparing the two percentages, then you can't; they're percentages of different things, and without comparable timings. If you had a debt of 100M and a deficit of 10M, then even if you reduce your deficit by 90% your debt will still be increasing by 1% per year. \n\nSay I did that over 10 years, then I could spend 9 of those years still accruing 10M a year and only lower the deficit in the final year. So my debt would have gone up by 91% and my deficit down by 90%.\n\nEqually I could bring down the deficit in year 1 and so only increase my debt by 10% while bringing the deficit down by 90% (though of course I would choose a different time period -1 year - to report on in this case lol).", "> If the national debt is the sum of money borrowed to cover the deficit, how is it possible that the national debt increased so much while the deficit decreased?\n\nThe national debt is the total of yearly deficits. It grows every year that we run a deficit.\n\nIn the 8 years under Obama the deficits were:\n\n$1.4 Trillion\n\n$1.2 Trillion\n\n$1.3 Trillion\n\n$1.1 Trillion\n\n$679 Billion\n\n$485 Billion\n\n$438 Billion\n\n$585 Billion" ]

[ "They are made of different plastics. Usually the soft plastic bottle is made of PET (indicated with number 1). The hard caps are made using PP (number 5).\n\nIt is currently not economically viable to recycle plastics PP, so most recycling plants don’t have the equipment to handle it. If a significant amount of PP were fed into the machines recycling PET, it could jam or destroy the machines.", "You throw the whole bottle into a single industrial grinder and seperate it by submerging the grinded material into water. The PET sinks to the bottom and PP float to the top due to differences in material density compared to the water. You scoop up the PP on top for your PP end users and you have the remain PET for your other end users.", "They can be, depending on your recycler. They are recyclable here in my municipal recycling program, as long as it is attached to the bottle. Same as metal caps from glass bottles—if they are loose, they are too small and the size is a problem, but if they’re all collected in a can or something, the material itself is recyclable.", "Actually lid is also recyclable, recycle plastic really low in quality compare to virgin raw material, as much as 30% of recycle plastic in virgin raw material can degrade the quality that is the biggest hurdle of plastic recycling. Most places I know accept plastic bottles with lid for recycling" ]

[ "Imagine you buy a new TV. You bring it home, you're gonna replace your old TV. Maybe the new TV is the exact same size as the old TV, so it doesn't take up any more space. But obviously it takes space just to switch them out. You're gonna make a mess, there's gonna be boxes, you have to move the old TV out of the way, etc. So after you're done and you clean up, it doesn't take a lot of space. But you need a certain amount of space just to move stuff around, and your computer is asking for the same thing.", "So you download the update (100MB).\nThen, it gets decompressed to a scratch directory (500MB).\nThe old versions of those files get backed up in case something goes wrong (400 MB)\nThen it gets copied to the final destination (new files 100 MB larger than the old files).\n\nAt that point, you're at 1.1GB total. Then the backups get deleted bringing you down to 200MB (100 for the installer, 100 for the larger updated files).", "Think about it like an inflatable boat. While deflated (compressed) it takes up very little space and is easy to move around, but you can't really use it for its purpuse. But when you inflate it (decompress) you can use it as intended.", "It might be highly compressed, and decompression takes up space, then it has to install which takes up more space. At the end the decompressed contents are deleted. So you end up needing 2x the file size + the download to install something.", "Setup files are heavily compressed to save download bandwidth/time. During installation, the setup program unpacks all the files into proper locations. You may be asking why don't just use those files still packed to save space? It's because uncompressed files can be read and written to, fastest, at full disk speed. If you can accept slower read/write speed for lower used space, you can set the folder to use compression. For Windows, right click the folder > Properties > Advanced button > enable \"Compress contents to save disk space\" and click OK a few times to compress the folder. It will free up some space but may not back down to 100MB since Windows NTFS may use different compression algorithm from the original compression." ]

[ "Because traditionally, \"associates\" are sort of partners in the company, but \"employees\" are assets. It's not official or anything, but people are soured on capitalism and this little pat on the back is meant to make workers feel better about it." ]

[ "Pitch is how our brain translates wave frequency. Wave frequency is how many waves impact our ear in a given time.\n\nThe sound recorded is a series of wave formations to be recreated. Play it faster and it has to make those waves in more rapid succession. Thus it plays back at a higher frequency. Thus our mind hears a higher pitch." ]

[ "> Wearing polarized sunglasses when driving in the rain during the day will help a driver see better. Polarized sunglasses work to block horizontal components of scattered or reflected light, which means they help counteract the scattering of light that atmospheric effects like fog or rain have on daylight. \n\n_URL_0_\n\nEverything gets all shiny when it's wet so even though there's less bright light on a rainy day there's still a bunch of light scatter, glare, and reflections. Wearing polarized lenses, not just any pair of sunglasses will do, helps reduce those effects", "Light has an orientation.\n\nSunglasses are (usually) polarizing filters. That is, they filter out the horizontal components of the light and only let the vertical components through.\n\nWhen you look at a regular light source you'll get all kinds of different orientations. So viewing it (or normal objects that the light bounces off of) through sunglasses just makes it dimmer.\n\nSome light is already polarized. In particular, light that bounces off the ground at a small angle (like the road in the distance) has strong horizontal polarization. Rain will make the road shinier and increase that effect. But if you wear sunglasses that horizontal component is blocked so they'll reduce almost all of the glare but only some of the regular light and things look clearer.\n\nPhone screens also have polarizing filters so you get the same effect. But if you turn your phone 90 degrees the phone will filter out all the vertical components and your sunglasses will filter out all the negative components so your screen will go completely blank." ]

[ "* 100 km/h is a speed.\n* Humans don't feel speed, we feel force and force comes from acceleration\n* Acceleration is caused by two things:\n * Change of speed\n * Change of direction\n* When seated in a train or car you aren't accelerating very much. Sure there are small changes in speed and direction.\n* On a rollercoaster, the entire point is the make you *feel* it. So the entire ride is designed to change your speed and direction.", "The roller coaster is open to the air, and has stationary objects placed in very close proximity to it. It is from feeling the wind and seeing things move past quickly that you develop the sense of speed.\n\nThe rollercoaster also is near continually changing direction. When changing direction you will feel the interaction between your body and the vehicle, becoming aware of the motion.\n\n\n\nEnclosed a rollercoaster and run it on a flat track and it will seem quite slow. Ride a train through a tunnel and it will seem quite fast.", "It has to do acceleration (how fast the speed changes). The acceleration in a rollercoaster is much higher than in a train or car (usually).", "A rollercoaster tends to change directions suddenly. Do the same in a train or car and it will feel plenty fast too." ]

[ "Answer: the idea is that by giving tax breaks to job creators/companies, theyll use the extra money to expand and hire more workers/produce more goods/etc. That will stimulate the economy and cause more people to have jobs and work.", "Honestly just have a look at the Wikipedia article for 'supply side economics'. It's a very good overview.\n\nBasic idea is: if people who have the means and the ability to build and operate businesses are provided with easy operating conditions (low taxation and low levels of regulations), then the increased level of production will lead to increased tax receipts (despite the lower marginal tax rates) and increased wealth generation.\n\n'Demand side economics' is the diametrically opposed view.", "The theory was that if you give tax cuts to the wealthy, they will spend more and invest more and that will create jobs for those lower down the economic ladder. But 40+ years of practice has proven that it's not the case. Time and time again, tax cuts for the wealthy have not produced the type of economics stimulus predicted by those advocating a tax cut.", "Trickle down economics is a pejorative term for supply side economics. The idea is that if you cut regulations and give tax cuts to people who make goods and services, they'll innovate and reduce the cost of those goods and services. \n\nDemand side economists say the opposite. You raise taxes and increase regulations. Then redistribute wealth so people have more money to buy things. Then people will have a greater demand for goods and will buy more things. This idea is related to the trickle-up effect.\n\nNeither side is objectively correct. There are Nobel Prize winners, US Presidents, famous academics, and regular people on both sides of the argument. You can easily create an argument that mocks the other side. For example:\n\n**To mock supply side economics, you could say:** Trickle down economics is the idea that if you give money to the rich, they will create jobs for everyone. What really happens is that the rich keep all the money and only the scraps will trickle down to the common person.\n\n**To mock demand-side economics, you could say:** The price of a computer is $10,000. Instead of giving tax breaks to computer companies so they can innovate and reduce the price of computers to a few hundred dollars each, we should tax the rich and give every person in America $10,000 so they can buy their own computer." ]

[ "Head lice come from eggs that are laid by other head lice. Head lice cannot spontaneously generate. An infestation starts by being spread from another infestation.", "The short of it is that lice infections *don't* start. Just like diseases, there are \"reservoirs\" of lice that don't get eliminated. At any given time on earth, *someone* has lice, and they'll end up spreading it to other people before they get deloused, and so on. There are no 'new' infestations, just sharing from one person to another over time and space. It's theoretically possible that, similar to Small Pox, lice could be eliminated from the world by getting all humans deloused and keeping them that way long enough for all the eggs to die.\n\nThus \"where lice come from\" is more of an evolutionary question.", "Lice spread by very, very small eggs. These eggs can get off the scalp and onto the hair. Then anything that touches the hair can collect them. If that something provides them a new host, when they hatch they will give the new person head lice.\n\nThat's why beauticians soak their tools in disinfectants and clean them between customers.", "Lice cannot spontaneously come into existence. They are born from eggs, laid by other lice. So those lice came from somewhere else, likely someone else.\nIf you're asking where do they originate, I'm sure you could google the evolution of head lice and find some information there of how they've come to evolve the way they have. u/GreenStrong had some great info below, also super interesting." ]

[ "1. Submission of Paper\n\nThe corresponding or submitting author submits the paper to the journal. This is usually via an online system such as Scholar-One Manuscripts. Occasionally, journals may accept submissions by email.\n\n2. Editorial Office Assessment\n\nThe journal checks the paper’s composition and arrangement against the journal’s Author Guidelines to make sure it includes the required sections and stylizations. The quality of the paper is not assessed at this point.\n\n3. Appraisal by the Editor-in-Chief (EIC)\n\nThe EIC checks that the paper is appropriate for the journal and is sufficiently original and interesting. If not, the paper may be rejected without being reviewed any further.\n\n4. EIC Assigns an Associate Editor (AE)\n\nSome journals have Associate Editors who handle the peer review. If they do, they would be assigned at this stage.\n\n5. Invitation to Reviewers\n\nThe handling editor sends invitations to individuals he or she believes would be appropriate reviewers. As responses are received, further invitations are issued, if necessary, until the required number of acceptances is obtained – commonly this is 2, but there is some variation between journals.\n\n6. Response to Invitations\n\nPotential reviewers consider the invitation against their own expertise, conflicts of interest and availability. They then accept or decline. If possible, when declining, they might also suggest alternative reviewers.\n\n7. Review is Conducted\n\nThe reviewer sets time aside to read the paper several times. The first read is used to form an initial impression of the work. If major problems are found at this stage, the reviewer may feel comfortable rejecting the paper without further work. Otherwise they will read the paper several more times, taking notes so as to build a detailed point-by-point review. The review is then submitted to the journal, with a recommendation to accept or reject it – or else with a request for revision (usually flagged as either major or minor) before it is reconsidered.\n\n8. Journal Evaluates the Reviews\n\nThe handling editor considers all the returned reviews before making an overall decision. If the reviews differ widely, the editor may invite an additional reviewer so as to get an extra opinion before making a decision.\n\n9. The Decision is Communicated\n\nThe editor sends a decision email to the author including any relevant reviewer comments. Whether the comments are anonymous or not will depend on the type of peer review that the journal operates.\n\n[Source](\n_URL_0_)" ]

[ "A taser will cause localized muscle contractions while actively shocking, but relies on pain and shock (the medical kind, not electrical) to 'drop' people. Someone who is riding on the right chemicals (even just adrenaline, potentially) can have a great ability to ignore or not feel pain. Thus, being tazed will stop them *while they're being shocked* but they won't suffer the 'aftereffects' that *keep* them stunned.", "Being drunk makes lots of things, like even punches, hurt less. It dulls your brain in general, pain sensitivity is just part of the package.", "People go down (and stay down) after being tased because of the pain. When you’re under the influence, you don’t feel the pain as much, so you don’t go down." ]

[ "The k is used to symbolize the prefix \"kilo\" which is derived from the greek word for 1,000. Other common uses include a kilometer (or a thousand meters) or a kilogram (a thousand grams). \n\nC is similarly used to donate a hundred for a similar reason, derived from \"cent\" (greek for a hundred). Commonly used in a c-note (hundred dollar bill), percent , centimeter, and cents (like the coin)." ]

[ "There are plenty of services where you can pay someone in order to have their bots give you fake followers or likes on social networks like instagram or facebook. Many people use these services to promote their posts in hopes of attracting more attention from real people. Bots can also repost, which is done for similar reasons. Lastly, they can be used to steal accounts and run scams. Bots don't make the most convincing scammers, but they can usually be used to scout for potential victims or even exploit people with particularly simple scams." ]

[ "Simply because animals don’t have anything like the same cognition as human beings. The sounds they make are only a ‘language’ in a rudimentary sense and don’t have the nuance necessary to engage in any kind of constructive conversation; therefore they cannot be ‘translated’ into anything close to a language system." ]

[ "Donations from folks that want to know if this school format works better than other solutions. King James isn't planning to take over all education for everyone, only examine a format and try to learn from it." ]

[ "Rather than the capsaicin found in chili peppers, horseradish is hot because of a chemical called *isothiocyanate*. Think of it like those liquid plumbing clog removers that come in separate bottles and are activated by mixing together. Basically, those two chemicals aren't hot by themselves, but the product is." ]

[ "I can't answer the whole question, but I can answer the one part about turning grey. No, they do not turn grey while hanging off your head. Hair has color because of cells called pigments which are like color deposits (you can see them in your hair under microscopes, pretty cool!). When hair grows out of your follicles, it will keep its pigments forever. When you get old, your hair follicles have trouble producing these pigments. So as your hair grows out, the new hair is simply grown without pigment, therefore grey.\n\n\nQuick edit to try my hand at really ELI5:\nYou have little hair factories on your body that always are pushing out hair, bit by bit making your hair longer. The factory paints the hair as it goes out, but when you get old, they run out of paint! So the stuff that is already painted stays painted, but the new stuff is just unpainted grey. But eventually the painted hairs fall off, leaving only unpainted hair." ]

[ "Yes, but it takes time to figure out how much harm, what kind of harm, and how it compares to smoking various substances. There are good reasons to believe that vaping is safer than smoking the same substance, especially tobacco. Having said that, early evidence of immune system and lung damage from vaping (regardless of the presence of nicotine) should alarm anyone. If you're smoking tobacco, I wouldn't hesitate to switch to vaping, but I'd still have slowly stopping altogether as a long-term goal. If you're not smoking, then it would be pretty crazy to take up vaping regardless of the presence of nicotine in the \"juice\". \n\nIssues include, but are not limited to: \n\nInhaling propylene glycol and glycerine is a pretty new thing, in terms of this amount and frequency. They're \"Generally Recognized As Safe\" (GRAS) by the FDA, but that's in the context of limited exposure, usually through ingestion. \n\nThe heating elements range from very safe and efficient ceramic or titanium, to cheap shit with plastic batting. Burning plastic and metal, or burning \"juice\" is going to be a chemical cocktail you don't want any part of. \n\nWhat's in the juice? This is some wild west, unregulated/poorly regulated stuff, and I wouldn't trust it personally. Sure, some people make their own, but I'd still be cautious. This goes especially for the flavoring agents, that are only GRAS as flavoring additives in food, not something you heat and inhale all day.\n\nIt's fucking obnoxious, and sooner or later (probably sooner) vapers are going to get the same treatment as smokers. \"It's better than a cig\" is only really compelling when you're a former smoker, for everyone else it's just a non-starter.", "Yes, but nowhere near as bad as cigarettes. \n\n & #x200B;\n\nThere's no long term research into the effects of vaping tho, so vapists are practically strawberry shortcake puffing guinea pigs. \n\n & #x200B;\n\nI'll stick to the cigs tho, they make me look extremely cool." ]

[ "The prosecution can decide to drop the charges, immediately ending the trial. The defendant goes free.", "This would just be \"dropping the charges\" against the defendant. The prosecution represents the state, and part of their job is to decide if they have enough evidence to prosecute someone or not. If they decide that a person isn't guilty of the charge they placed on it, then they can drop that charge. No charge, nothing to defend against, no court proceedings.", "In the US, wouldn't that just be the state choosing not to press charges or choosing to drop charges?\n\nThe prosecution is only there to present the state's case to the court. They are not the jury as well because letting them choose the outcome of their own case would be a massive conflict of interest.", "The prosecutors can drop the case. They will talk to the judge to say they are not proceeding with prosecution. The judge will then dismiss the case and the defendant leaves." ]

[ "* Some calls are made by mistake without the knowledge of the caller. \n* If such a call makes it to the recorded message part of a voicemail prompt, it is likely to continue until the voicemail recording session times out. \n* Sometimes toll numbers are called in a billing scam. The details are complex but the main idea is to keep the toll line on the call as long as possible to increase the fee the scammer phone company can collect.", "They check if number is active, also some of the numbers are premium and if you call back they will charge you a lot" ]

[ "> Always wondered how do car / house / personal liability insurances avoid \"cheaters\" or misusage?\n\nIf you make a lot of claims, your insurance rates go up. Also, the insurance companies know that a certain amount of fraud is inevitable and they build that into the premiums that they charge.", "As for profits, consider this: \n\nThe U.S. population is around 330 million, the working age (18-64) is around 63% of that, for around 208 million people. Lets say half of those people have car insurance (cause lets be real, many people don't, but half is probably a very low estimate as car insurance is quite important and often mandatory to legally drive). \n\nAssume very low insurance of $1,200 per year per person (I say very low because that's about what I pay in my area and it's on the low end for my area and lower than I've seen for lots of areas). \n\nThat's an estimated annual amount of about $124,800,000,000.....this is also ignoring the fact that many people have more than one vehicle but only every drive one at a time, but it also ignores other cases that might lower the amount (lower premiums, multiple car plans, etc) \n\nFrom what I can find, the average number of reported accidents in the U.S. per year is around 6 million. \n\nAssuming all of the above (which was found or calculated based on findings from some Google searching), that leaves an average amount per accident of around $21,000. \n\nNow, if you assume 10,000 people crash cars and have claims that add up to $100,000 each, that only amounts to about 1% of the above estimated annual earnings. \n\nNote: There's lots of speculation about that can't be accounted for without significant research, but when it comes down to it the amount of accidents compared to the amount of insured drivers is large enough that insurance companies do turn a profit.", "Lots of math.\n\nLet's say you live in a town of 100 houses. Every year, 10 burn down in accidents, 15 get robbed, and 5 get blown down by a tornado. A subsection of 25 of them have 5 flood every year.\n\nYour insurance will figure that, each year, you have a 10% chance of a fire, a 15% chance of a burglary, 5% of a tornado, and either 0 or 20% chance of a flood. Take these numbers, multiply them by how much they would pay out if it happens, and that's how much your premiums have to cover. Add an extra amount for admin cost and profit, and you're running an insurance company.\n\nIn practice, there's a lot more things to factor in, and trends in these rates also have to be calculated.\n\nPeople are willing to buy insurance, even though someone else is profiting, because a 1% chance of losing $100,000 is \"worse\" than a 100% chance of losing $1000, even if they're statistically the same.", "Doing that is fraud. Most like people don't like commiting fraud because if they get caught they can get fined or go to jail. Or the insurance company won't pay out, and then they've crashed their car and are now screwed. \n\nThat said a lot of people do commit insurance fraud and it's priced into the cost of your policy. Insurance companies will hire investigators to try and catch fraudsters, especially around medical payouts. If you get a payout because you say you're injured at can't work, they may investigate you. They are probably watching your Facebook and Instagram. So when you post photos of yourself playing sports the next day, they'll bust you as your injury is fake.\n\nThe other thing is insurance usually doesn't pay 100% of the cost. There is a deductible you have to pay first. They are hoping you'd rather just not crash than purposely crash and pay a few hundred dollars just to get your car repainted." ]

[ "Fish near the surface where the lightning strikes die, but those swimming deep underwater and away from the lightning keep swimming. The charge dissipates in water.\n\nAs people tend to swim near the surface, on account of breathing air and all, which puts us right in range of the lightning.\n\n\nIn addition, land usually has tall objects around like trees and buildings, so the likely hood of you standing near the strike is low, but in water there aren't buildings or trees acting as lightning rods." ]

[ "People aren't following any kind of rational process for deciding what names to give animals. Sometimes a superlative name sticks, and sometimes it doesn't." ]

[ "Capacitive touch screens do not detect rubber, it detects conductive things. Styluses are made from a special conductive rubber or plastic that conducts electricity like your fingers do.", "Touch screens work with anything that can hold an electrical charge. Fingers, rubber, water etc all do. Towels, makeup brushes etc (I'm in the bath room) don't." ]

[ "Sodium consumption is vital for virtually all animal life on this planet and all species have evolved a drive to find and consume it. Wild animals will find what are know as salt licks, which are literally patches of salt that have made it to the surface that the animals lick, plants that naturally have high levels of sodium, or other sources of salt. \n\nHumans being intelligent and tool users simply got into the habit of mining these sources of salt, cleaning the salt to remove impurities, and grinding it up into a more easily consumed crystal size.", "Sodium is a useful nutrient mineral that along with potassium, among other things, makes your brain run. Since salt os so essential your body “craves” salt. This “craving” is what makes blood so tasty along with “heme” or protein. \nNow once you taste blood, you might start to look for salt elsewhere. \nSalt can be found in the ocean, on the shores of salty lakes and in ancient sea beds. \nOur ancestors were clever and found many ways to obey the crave." ]

[ "You will smell before you taste. For example a fresh habanero will give a spicy aroma while cayenne powder will be an after heat. Remember that smell is an important component to tasting food" ]

[ "From personal experience it seems to be something to do with pressure in the head being somehow equalised by the rush of blood/pressure from vomiting", "Never heard if this before. But it reminds me of my issue, where I'll suddenly feel really sick for like 10 minutes followed by it stopping and ALWAYS a hard as hell sneeze. Then all back to normal. This happens nearly every day, and even other people point it out. \n\nI can't figure out why it happens in that order. But if my stomach turns sour suddenly, I can bet money down that I'll have a uncontrolled super sneeze in like 10 minutes. And the sneeze is super sudden normally, like I don't feel it build up or anything. \n\nMy body is a mystery." ]

[ "The molecular makeup of mucus, long strands of molecules make liquids more viscous. Same as egg whites." ]

[ "It's important to keep in mind genetically modified doesn't mean \"modified in a lab\". \n\nMost of our farmed food is genetically modified. Every piece of corn you've ever eaten is genetically modified. So for most food, the way it's genetically modified is the same way dog breeds are created—selective breeding. Farmers grow their crops and select the biggest or tastiest and instead of selling them, they select those seeds to replant. Then the next generation is selected to be bigger and tastier. \n\nGrapes used to be the size of peas. Corn used to be the size of carrots. And apples used to be good for only cider (they were all basically crab-apples). We've been modifying our food since we started farming. \n\nAs for lab-modified food, there are a few ways, but *recombinant DNA* is the most common:\n\nScientists identify a trait they want to add to a crop (like insect resistance). They find the gene responsible by turning the gene off in a plant that has the property they want in game of guess and check. Then they create a *plasmid*—a little circular bit of DNA. They can use new techniques to insert the gene directly in the plant (CRISPR), but most of the time, they put the plasmid in a bacteria that they can breed at high volume. Then they use a molecular cut and paste with enzymes called *restrictase* and DNA ligase to cut the gene out and paste it into the crop.", "For plants essentially what happens is scientists grab bacteria, inject it with the desired gene and then inject this into the crops." ]

[ "Remember the first time you heard someone with the last name of Butt? It's initial funny is overwhelming. Well thats happening all the time for babies because everything is new." ]

[ "During a big yawn along with your jaw and neck you also move your upper jaw muscles which constricts the ear canal making sounds feel muffled. \n\nSometimes those muscles vibrate , vibrating your inner ear and make you internally hear the sound you hear inside your ears during yawn" ]

[ "Most the time its not. Its when they get back up its a nervous relief" ]

[ "There are different kinds of last names. Job based, Location based, feature based, familial (son of, daughter of, descendant of, etc), and assigned. \n\nFor Job based names you took the name of the profession that you had. If you changed profession, then you would generally change or amend your name to reference that. Most professions were passed down father to son, but apprentices were also a thing and they would change their name from what they had as a child when they took up their trade. \n\nLocation based. Names like Hill, Dale, German names with \"Von\", Spanish names with \"De\", etc are names that are location based. John Hill would be a very local oriented name meaning John who lives on the Hill. The last name Von Bismark means someone \"of Bismark\" which means someone who is from the city of Bismark. These would commonly change when you changed where you live, though the \"Von\" and \"De\" names changed less often as they are more origin based. \n\nFeature based names are things based on someones features. So Little would be attributed to someone who was small (or ironically to someone who is huge), the last name Green could be given to someone with green eyes. Black could be given to someone with black hair or skin. Etc. These names could change from one generation to another. \n\nFamilial names. Some names are based on the name of your father. So John has a son named James. James could be called James Johnson. James then has a son named Peter, he would be called Peter Jameson. So on and so forth. In English we tended to stop the trading of names after a time, and just stayed on one for each generation but other cultures such as Iceland still switch every generation (and they have a different variant for son's and daughters). O', Mc', and Mac in the Gaelic/Celtic cultures means descendant of. They would be based on some famous or \"famous\" ancestor that the family found to be important. \n\nAssigned names were typically the kind taken or given to nobility. This name was likely the first to be passed down unchanged." ]

[ "**ELI5:** \n\nWe often know what their musical instruments sounded like. \n\nAncient peoples sometimes left clues about how their instruments were made. Then, a smart man can make a copy of the instrument - and play it! Sometimes, musical instruments are buried with people, and we can make a copy. Sometimes, an old type of instrument is still in use today. Drums are very old, and very common - you know what a drum sounds like. Flutes are very common, too. If you know the size, shape and makeup of an instrument, a craftsman can probably make a decent copy. Making old style musical instruments is a hobby for some people, and a job for others.\n\nWhat I do not know is what *tunes* were played - another poster may have the answer to that question.", "We don't really as accurate musical notation was not developed until around the the late middle ages and renaissance in Europe. Fun fact: The Catholic Church developed the basic idea of staves, notes, and other basic music notation found in modern music notation. It all stemmed from them wanting to standardize the chants of the Church. Instruments were not originally allowed, and to this day we call voice-only music a capella (in the manner of the church.)", "I found a video on YouTube a while back purporting to have the oldest known melody at 1400 b.c. Music has come a long way!\n_URL_0_", "Music theory and history are some of my favorite subjects!\nMusic has evolved much like language over the years. Just like we have Shakespearean English and barely recognizable old English of Beowulf; written music has certain periods and things that make them distinct but similar. Just like a linguist can read a long dead language a musicologist maybe able to read a notated melody. Unfortunately, a lot of older styles of music notation are vague and/or improvisational and not as specific as it’s metaphorical counterpart. So we have educated guesses as to what ancient music sounds like, but we don’t really know. Some of the vagueness can be taken away by what the instrument sounds like. As another commented, the structure and composition of an instrument often informs use and function.", "Not exactly ancient music, but there are some songs from early America/England and other places that were passed on through ceramics. Musicians were able to scratch sounds into ceramic pots and other wares similarly to how records were/are made!\n\nEdit- yes I would agree more like a music box, I didn’t even think of that comparison!" ]

[ "The short answer is that the process is very similar, but the results are night and day. If you freeze a head, it's *not* coming back using any conceivable technology; it's done. In addition to the reality of widespread cell depolarization and death in the brain, what actually dying doesn't finish, the process of freezing will. Even with \"antifreeze\" added, you're still talking about huge sections of tissue being lacerated by ice crystals. Ever freeze and then thaw out a steak? See the mess of liquid it's sitting in, and how it's gotten a bit mushy? Yeah.\n\nSperm and eggs are easier because they're both single cells, are extremely simple, and have a *huge* surface area to mass ratio. As a result you can literally flash freeze them in an instant, which just isn't possible with something like a whole head. Even then, you don't recover anything like all of the sperm or eggs, but you don't need to. Losing a bunch of sperm in particular isn't a problem, you're freezing millions of them after all. A brain however, is kind of a delicate organ containing many billions of cells, the arrangements and states of which *are you*. Losing a bunch of them to the process, not to mention the ones you lost to actually dying and transport to the facility, is just too much even if you could be thawed without the \"mushy steak\" problem.\n\nFinally, while not a technical hurdle, it's worth considering that eggs and sperm are stored by the people who \"made\" them, and who value them highly. They're not intended to last forever, and wouldn't, and they're something that people who have a connection to them want to recover and use. A frozen head on the other hand? How many generations would need to pass before no one is left to give a crap about it? What future society is going to prioritize reviving a bunch of primitives with more money than sense, and no connection to any living soul?" ]

[ "Accessing an array is O(1). Perhaps you mean searching for something in an array. If the array is ordered then searching is O(log(n)). For an unordered array the search is O(n).\n\nHashing means taking the search key and processing it in some consistent way to produce a single number which you can then use as the array index, i.e., the storage location in the array. If the keys are words then a simple hash would be to add the ASCII values of all the letters in the word so you'd find the entry for the word \"A\" in array slot 65. No searching is required, so the time to find an element doesn't depend on the size of the array (though it does depend on the size of the key).\n\nObviously there are problems with the above simple hashing scheme. The words \"ab\" and \"ba\" would be stored in the same slot. The array would need to be very long to have space for long words. Read up more on [hash tables](_URL_0_) to find out how these and other issues are handled.", "If you're searching for something in an array, you have to first look at the first item in the array, then the second item, and so on until you actually find the item. Assuming the item you're looking for is equally likely to be in any position in the array, you will on average have to check n/2 positions in the array to find it, which is O(n).\n\nIf you're looking something up in a hash table, you give the object to a hash algorithm and get back an index. Then you just look in that one index for the item. You don't need to search through the entire table because the object's identity corresponds directly (via the hash function) to the position in the table where it is located, unlike with a list where the item could be anywhere." ]

[ "There are a few of different reasons. One is the fat content, the second is how the meat is prepared, another is the location on the animal that the meat comes from.\n\nYou can even taste that last factor with other meats, like chicken. Compare the taste of a chicken breast (white meat) to a chicken thigh (dark meat). Even if they are prepared the same way, they will taste different because of the basic differences in the meat.", "Both cuts are cured (soaked in a salt, sugar and spice soluiton to help preserve it by replacing the water in the meat with salt to make it less desirable to bacteria) and then smoked to give it more flavour and further the risk of bacteria growth.\n\nBacon traditionally comes from the pork belly which is very fatty and rich. The meat tends to be tender since the muscles around the underside of the pig don't get much exercise. There are other cuts used like the loin as well, but what most people think of when you say bacon is pork belly. \n\nHam is usually made with the leg, a much tougher muscle since it keeps the pig standing. It's usually aged at very carefully controlled conditions for a long time to dry it and allow certain beneficial bacteria to help alter the flavour. There are all kinds of hams ranging from the cheap supermarket lunchmeat to several year old ham, aged in the basement of a Spanish monastery by monks that only pray and make ham that can cost $20-30 per pound or more." ]

[ "Some vitamins are not water soluble. For instance, you can take a great deal of vitamin C. You’ll just pee it out. (Extreme doses can cause some discomfort.) However, vitamins A,D,E and K along with others can be very dangerous when misused. Overdose can occur and can have issues from skin discoloration to death. \n\nThe MOST anyone should need, unless recommended by a doctor, should be ONE multivitamin per day. Chances are you’re getting enough from 3 meals, but if you have bad eating habits, 1 per day is plenty.\n\nEDIT: Some replies below mentioned some mild discomforts from too much vitamin C, so I’ve changed it from “as much vitamin C as you like”, to a “great deal of vitamin C”.", "**Important:** There is such a thing as *too much vitamins*. Vitamins in excessive amounts can be toxic. OP's mom should talk to her doctor about her vitamin intake.", "If you have an absorption issue then yes, vitamins are needed. If not, they will just pass through your system so long as your diet is decent and the quality of food still retains essential nutrients. Food that has been sitting out in a produce sections has lost it's nutritional value. Frozen is better unless it came straight from the farm. People with liver and thyroid issues should take vitamins or receive infusions. The lack of nutrients being absorbed through the liver can lead to obesity, chronic fatigue and depression.", "If you eat lots of fresh fruit and vegetables probably not. But as people get older they need to eat less, and they digest and absorb vitamins less efficiently. So, it may be more beneficial for older people to take vitamins or get a juicer and make fresh juice.", "Echoing what others have said except when you hit your late 40’s early 50’s. See a doctor and have them do a blood test - when I hit 47 my doctor found deficiencies." ]

[ "Think of neurons as groups of people in different rooms of a building. Each person is very good at one thing and only one thing.\n\nFor example, people in the first room can only smell stuff. And each one can only tell you the probability of it being a certain thing. So one guy can smell and tell you that he’s 40% certain that it is coffee. Another can tell you that he’s 99% certain that it’s sugar.\n\nSo you walk in with an unidentified object, and the people in the first room tells you what they think it probably is. \n\nThen you walk into the next room, where people can touch and tell you the probability of it being a certain material. \n\nIn the next room, the folks can lick and tell you the probability of it being the thing they specialize in. \n\nBut if the guy in the first room who specializes in poisons says this is 99% poison, the guy in the 3rd room (lickers) will pass on tasting it.\n\nSo each room gives you information that the folks in the next room use along with their own skill to decide how likely the object is whatever they specialize in. \n\nAs you make your way through more and more rooms, the accumulated probability information allows the people in the last room to make a fairly confident statement as to what the object is.\n\nFor example:\n\nRoom 1: “This is red in color (99% certain), orange (45%), green (4%)”\n\nRoom 2: “This is the size of a finger (95%), the size of a fist (6%), size of a football (0.5%)”\n\nRoom 3: “Smells edible (88%), smells like plastic (8%), smells like metal (1%)”\n\nRoom 4: “Based on all the info above and its taste, this is hot pepper (97%), lipstick (2%), a pen (0.2%)”", "I'm not really liking the other explanations here, so here's a new one.\n\nNeuron is a thing that listens to many channels, and then does a rather simple choice of sending or not sending a signal. Or rather, it decides how much of a signal to send. Then multiple other neurons listen to that neuron.\n\nArtificial neural network is a mesh of neurons and their connections, simulated in very barebones way.\n\nWhat you basically get is, you send something in to the network, and that something is listened to by some neurons. These neurons then activate to varying degrees, and other neurons listen to those signals, and so on, until some signals you've designated as \"output\" where you are listening to them instead of more neurons.\n\nSo it's a simple \"stuff goes in, neurons get wild, stuff comes out\". Slightly more accurately, numbers go in, and numbers go out, as we use numbers to tell how strong each activation was.\n\nNow, what happens inbetween input and output could be many things. How each individual neuron reacts to the signals they receive can be tweaked. And the cool thing is, we can make this continuous, so that small tweaks result in small change in output. Like, if you make neuron X less sensitive to its input so that every time it gives out a weaker signal(ie. a smaller number) than before, this should only slightly change the output.\n\nThis means we can train these networks by feeding them data, checking what comes out, and evaluating how good the result was. Then we want to make slight changes so it becomes a little bit better. Then you repeat the process.\n\nAnd the great revolution here was, this process can be automated. We have a mathematical formula that tells you how to tweak the neurons to make it slightly better at the task you specified. So all you need to do is get data and figure out how to evaluate the output. After that, neural network can be automatically adjusted to become better and better at that task you set for it. So in theory it means, you can have computer do things that you yourself don't know how to do, but you are able to give it data to train on, and you are able to give numerical evaluation of its output telling it how well it did.", "At the most Eli5 level, it's a machine/program designed to be very good at playing hot and cold.\n\nA single neuron takes in several numbers that you tell it, multiplies them by weights (other numbers) built into (and changeable by) the neuron, slaps the result with a fancy equation to keep it from being too boring, and spits out the results.\n\nBut when it starts out, it has no idea what it's doing. The built in weights are usually random to start. So what happens is you feed it some data that follow a pattern. You tell it \"when I give you the numbers 7, 2, and 5, you should tell me 8\". It looks at that and says \"dang, I got 12, that's too high. Maybe I should count the first number, which was 7 this time, less, so I get a smaller number next time\". Then you hand out another the numbers, tell it what it should get, and it adjusts again, and so forth. \n\nHow much less? Use calculus - not terribly complex calculus, but still calculus.\n\nSo that's a neuron. It's pretty cool, but it's also somewhat limited. What if, for example, you should count that first number less, but only in some circumstance. What you do is you start chaining neurons together. Do it right, and various (groups of) neurons will get better and better at detecting part of the pattern in your data, and others will figure out what it means when certain subpatterns are or are not found and so forth.\n\nIf you're interested and either know are are willing to learn a bit of programming, you can make some yourself to play with.", "The term is used loosely to describe a variety of schemes by which large amounts of data are mathematically manipulated to perform classification.\n\nImagine for a moment there's a large stretch of woods surrounded by various homes and businesses.\n\nNow, no one really wants to walk around the entire stretch of woods just to grab a Slushie. So they walk through the woods instead. When they do so, they trample the soil and bend the brush out of the way.\n\nAs more and more people take their own route through the woods, you'll quickly see 'paths' develop along the most common routes.\n\nThose paths are actually a form of information. If you find a path in the woods, it's connecting one thing to another. The existence of that path tells you something about the relationship between its two endpoints (even if that something is nothing more than \"Bill likes Slushies\").\n\nThat's basically what happens in a neural network. You have complex mathematical structures that are trained in some fashion to have such 'paths' through them that allow you to feed a large amount of data in the front end and get a classification out the other.", "Once you set it up, pick it’s shape, you have to train it so show it pictures or let it listen to things until it gets the right “what is this?” learned. \n\nOnce it is trained, you can show it new things and it will output what it has learned is closest or even output a synthesis or new idea.\n\nThe technical thing you get is a set of neuron weights that express an insanely complex function that has to be processed against new inputs when used. The special CPU that Google built recently is for the post-training phase where they use the trained model via the weights. It was far cheaper per op / watt and better than using Nvidia GPUs, which I think they still use for training..." ]

[ "The Fourier transform allows a function to be broken down into a sum of sine and/or cosine waves (although e\\^i can be used as well) of varying frequency and amplitudes. The goal is to use constructive and destructive interference from the waves to match the original signal as closely as possible.\n\nThe frequencies follow a fixed pattern (2\\*pi\\*n/T for n=0,1,2,3,...). The amplitude of each wave is the mean of the product of the function you're breaking down and the wave(1/T integral from 0 to T f(x)\\*sin(wnx)dx). The specific frequencies and cosine/sine wave depend on each function. So as an example, look at the first 3 terms of a square wave.\n\n1st: 4/pi\\*sin(wt)\n\n2nd: 4/(3\\*pi)\\*sin(3wt)\n\n3rd: 4/(5\\*pi)\\*sin(5wt)\n\nWhen all added together, they make an ok representation of a square wave. Adding more terms would increase the accuracy.\n\nIt's also really common to write the sin/cos terms as e\\^i(n\\*2\\*pi\\*x/T) because e\\^ix is related to sin/cos waves because math black magic.\n\nlet me know if this helps. This was kinda hard without just writing equations\n\nEdit: fixed error" ]

[ "Left Right balance is pretty much a non-issue. The people are all very close to the center of mass so it doesn't create much torque even if wildly imbalanced. Adjusting the trim flap a tiny bit on the end of the wing 10+ meters away results in significantly more torque.\n\nOnly front back balancing really matters because people in the nose and tail are far from the center of mass so if everyone is in the tail the plane will constantly want to pitch up" ]

[ "Pain is actually a very complex process. See, what you experience as pain happens in your brain, not your nerves.\n\nNociception (literally “harm perception”) is the process of a pain-sensitive nerve detecting a noxious stimulus and sending a message back to the brain. All peripheral nerves terminate at the spine, and pass the message on to the spine and up to the brain. But this doesn’t always result in “pain”.\n\nFirstly, there’s what’s called the pain gate. This is a spinal mechanism whereby the spine shuts out one pain stimulus in favour of another - it’s why rubbing a wound lessens the pain. The spine is literally blocking a portion of the pain stimulus in favour of the less painful rubbing.\n\nSecondly, there’s the brain itself. Whole PhDs have been written on this but the summary is the brain decides how much pain to feel based on context. Emotional state, prior experience, concentration and even language itself all have an impact on pain perception. It’s why an athlete might break their ankle but finish a race, while a person with a bad back experiences more pain when he’s having a bad day, or why injuries always seem worse at night when you have nothing else to focus on.\n\nPain tolerance is a mix of all these factors. Some people have alternative nociception pathways (there’s even a congenital syndrome wherein a person has none at all), some have excellent mental strategies for coping and some people literally just have better things to do. Some poor people have experienced something worse and can contextualise it differently. Pain is actually impossible to objectively measure - no two people will experience the same harmful event the same way.\n\nHope that helps.", "Honestly surprised this has so little engagement... so I'll give it a shot in the spirit of being helpful.\n\n & #x200B;\n\nPain starts at nerve endings and sends an electrical signal to the brain. Someone with high tolerance could simply have less sensitive nerve endings, some sort of signal blockage, or different mental processing of the signal. Pain can also be missed / ignored like any other sensation because your body takes in *far* more information than it can actively feed your conscious mind.\n\nELI5: Let's imagine you touch a hot stove. There is a news station in your palm that starts a broadcast to HQ (your brain), asking for help. But maybe your news station has older, slower tech. Maybe the wires are frayed and the message gets distorted. Maybe HQ isn't tuned into that channel when the broadcast starts or they think the danger is exaggerated. In any of these cases you would have a weaker pain response. How much of that is software rather than hardware I don't know.\n\n & #x200B;\n\nI don't know what changes take place in the body / mind while improving tolerance. Shot in the dark, but there is scientific backing for depression / anti-depressants affecting dopamine receptors which has an impact on how much you actually feel the effect of that chemical's release. Caffeine has a similar effect on blocking receptors meant to tell you when you're tired. I'll leave the proper ELI5 on that subject to someone with more secure understanding.", "I think Lawrence of Arabia describes it so beautifully; the trick is not minding that it hurts.", "Some nice answers here. I’ll try to contribute on some additional pain mechanisms that haven’t been discussed. \n\nThere are 3 areas of pain: detection, transmission, and reception. Each of these can vary from person to person yet we lump it all into “pain tolerance”. \n\nPeripherally, you can have heightened sensitization in your skin and many times that’s caused by inflammatory chemicals like prostaglandin. This is “detection” and I find nutrition, menthol topicals like IcyHot, and some NSAIDS do a good job here. \n\nTransmission is from the spinal cord to the middle of the brain called the thalamus. It’s where your endorphins usually try to diminish pain. Some people make more of these than others. Your spinal cord also has some areas along the way that diminish pain sensation, called substantia gelatinosa. Opioids can affect these areas really well...sadly sometimes too well. Physical therapy can be helpful too. \n\nFinally, from the thalamus to your outer brain, you have an inhibitory neurochemical called GABA. It is found in high concentrations surrounding your thalamus. I like to call it your “thalamic shield”, and it does what it sounds. The medications that can affect this? You might have heard of GABApentin or Lyrica (preGABAlin).\n\nThere are many more mechanisms but as far as simplifying the pain pathway, I like to use the 3 areas of pain and then understand why some things work well and some things don’t. \n\nThen throw a total wrench in the whole equation when you bring in genetic predisposition as well as psychology.", "You may be interested in [Lorimer Mosley’s](_URL_0_) and others’ work on pain science in Australia. It seems our brains play a huge role in our perception of pain. Tissue damage is only part of our pain response.", "Maybe some people have an innately high or low pain tolerance - I don't know if there's any science to that. Nobody in this thread seems to have provided any. But I've learned from years of martial arts training that 'toughness', or having a high pain tolerance, is largely mental.\n\nPeople have an instinctive reaction to recoil from pain - if you touch a hot pan, you gotta move your hand quickly or you'll damage it. But there are also a lot of situations where it's possible to disregard pain. You can't ignore it, that doesn't work, but you can train yourself to 'embrace it' by allowing yourself to feel the full extent of the pain and recognising that it's only a signal to your brain, it doesn't rule you and you can disregard it's message.\n\nThere's a strong connection between Buddhism and/or traditional Yoga practices, and some Asian martial arts (particularly Muay Thai) due to the common practice of training your mind to rule your body, and not allowing pain your body experiences to rule your mind. Have a friend punch you in the gut or hit you in the arm/thigh with a bat, and then watch some Muay Thai, and you'll realise just how much fighters can ignore. Body conditioning plays a part too, but nobody is so conditioned that a clean hard blow won't hurt - they just don't let it effect them.\n\nAs a note I want to mention that I've never really been able to make this work for chronic pain, only short term things. Other people have been talking about developing a numbness to chronic pain over time and I think that's equally true.", "This is a side note, but when taking a class in pain management for small children I was taught that proper pain management when doing frequent blood draws is vital for their future pain management. Apparently, having pain stimulus frequently can cause the body to increase the amount of pain receptors in the body, leading to a lower pain threshold. There are simply more signals of pain being sent to the brain than for the normal person, making them feel more pain from the same stimulus.\n\nIn this case, there might also be an added psychological component where pain increases fear, tension and anxiety, which increases pain and so forth.", "You know how some spicy food is too hot for you, but other people find it mild? That's how different pain thresholds work.", "In a very very very simplified answer:\n\nPain is a respone to a real or perceived threat. Pain is influenced by biological, psychological, and societal/cultural influences.\n\nThis means strange things can happen.\n\nNo threat=no pain, even in the presence of real tissue damage.\n\nYoure walking across the street and you roll your ankle. It hurts. Next thing you see is a bus barreling towards you. Youre probably out of the road fairly quickly. Your sprained ankle might not even hurt in this moment because the bus is the bigger threat. Once youre safe on the sidewalk, your ankle might hurt again.\n\nConversely a large perceived threat might hurt a lot, even in the absence of tissue damage or trauma. This is what we see in those with persistent pain states. The pain lasts far longer than the expected tissue healing times, and largely more of a \"processing error\" than true tissue dysfunction. The nervous system perceives a persistent threat requiring your attention and communicates via pain, stiffness, tightness, etc.\n\nSleep quality affects pain, stress/anxiety affects pain, diet, depression, genetics, environment, all affect pain.\n\nSo the answer is very complicated. And i could (and do) teach for hours on the biopsychsocial influences of pain in the individual.\n\nTldr; no such thing as \"pain tolerance.\" Its all about response to a real or perceived threat. If a particular noxious stimulus at that time of day in that state of mind in that level of health requires a response, and if so, how large based on about a million different variables.", "~~Might be a myth but iirc~~ ~~There's a myth~~ \n\n\n*It's open for debate whether women are better at handling higher levels of pain and men handle lower levels better, difference between handling cuts n bruises and having your body split in two by a crotch goblin, an evolution of the type of pain were more likely to experience.*\n\nPerception plays a very significant role. Pain can seem far worse if you're aware of what's going on, for example, you get a paper cut and don't notice until you see it, you recognise what it is and think \"this should hurt\" so then it does.Break a bone, that'll hurt, see bits of bone sticking out? Probably going to 'feel' worse for it.\n\nConversely if you're expecting something to hurt before the fact then the pain can become more diluted, ultimately pain is a damage alert system your mind doesn't need to alert you to damage so much because you're already aware of what's going on but if you stub your toe unaware, sweet mother of god sound the alarm I think we may have just lost a toe here...", "God I’m trying to ELI5 and this one is so hard. \n\nThe biggest contributor to the tolerance thing in my opinion is the memory of pain. There is a whole bunch of things that happen in the body when you are hurt to tell the brain you are hurt. This is “pain”. But the way you feel when you get hurt is the combination of the actual pain signal, and how your brain understands the signal. \nWhen people get hurt badly it affects the emotional part of the brain that responds to fear - this is a safety mechanism to make us afraid of things that are dangerous and hurt us. In the future, the same experience may cause fear, to avoid the danger that caused pain. \nThe emotional part of pain and the memory of the situation will affect future experience. For example someone who is very afraid of the dentist because of a terrible cavity as a kid will be afraid at the dentist. This fear can actually increase the pain signals that get through to the brain and increase the amount of pain that is felt for the same amount of pain signal. \n\nOverall, one big reason people experience pain differently is their own experience and memory affect how their brain feels pain in a certain situation. \n\nGetting away from things a 5 yo would understand - one reason the above is so important in treating pain is that factors that are emotional and not related to pain at all also affect many of the same areas of the brain as these past pain experiences. For example, people with depression or anxiety are more likely to experience chronic pain - certain areas of their brain can become sensitized to a pain experience more easily because of the other factors affecting fear, memory, etc. \n\nGetting a bit off topic, my explanation is why when someone says “I have a high pain tolerance” it usually means they don’t (source am a physical therapist). This person is thinking a lot about pain, their experience of pain, how much pain they have - all these things actually predispose the person to feeling more pain from the same experience than someone who is just oblivious or new to the experience or situation. \n\n[ edit: this last part was meant to be lighthearted :\nAs a side note, stop telling your physical therapist you have a high pain tolerance. It’s for their safety. Their eyes might roll so hard they go blind.]", "As an anaesthesiologist, I might be able to help here. The idea of 'pain tolerance' is not as simple as a describing pain pathways. As formally defined, pain is a 'subjective' experience, one that involves a physical AND emotional response to real OR potential tissue damage. The key here is that it is subjective - two people can experience the same noxious (painful) stimuli, but react to it very differently.\n\nThere are physiological explanations for why nociceptive (pain) signals are amplified or diminished - I'll save you from the long winded explanations, but if you really want to look up stuff, key works 'wind up', 'gate theory of pain', 'opioid induced hyperalgesia', 'endorphins' will shed light into why and how the body is able to modify such signals. But this isn't the same as \"pain tolerance\". This is simply the body increasing our decreasing the transmission of pain signals. These pain signals have to be 'interpreted' by your conscious brain to become 'pain'.\n\nPut simply, think of pain as an experience. There are factors that may increase your susceptibility to having a low pain 'threshold' (psychiatric disease, chronic pain) or factors that may increase your pain threshold (the commonly used treatment methods by chronic pain physicians - distraction therapy, yoga, massage, music, physiotherapy, etc).", "Plenty of good explanations here but I'll add my two pennies: threshold and tolerance are two different things.\n\n* Threshold is when you begin to notice.\n* Tolerance is how much it bothers you.\n\nThese can operate independently of each other. My dentists can pretty much work on me without freezing and I have been warned that I'm the type of person to show up for a check up and lose six teeth because of an abscess. It can sound great not be bothered by pain but it's a necessary signal to get something attended to.", "Fibromyalgia, Stenosis, surgery in 1999 for a busted vertebra in my neck, the bone graft didn't take (and it was my bone tissue, not a donor). Titanium plates and screws hold my neck together. My whole body leans to the right due to my S shaped spine. My knees ache. Surgery in both hands to stop my fingers from locking closed (one still locks, however). Surgery on right shoulder for torn rotator cuff and cysts, during which around 15 - 20 mm of arthritic bone was removed, but of course only on that side so it aggravates my condition.\n\nBut when I go to my monthly followup at my rheumatologist I report pain levels of 3 to 4 out of a scale of 10 (worst pain). He says that isnt very high, but I explained that when you really live in constant pain you try to suppress it, try not to make it the center of your life. Try not to talk about it. \n\nThe pain is bad but I have to tell myself that it isn't so great or I couldn't very well function. He has other patient's who scream bloody murder even though there is nothing evident on X-rays or MRI's. My diagnostics look all messed up, not hard to see that there is a lot that is wrong.\n\nGetting treated for serious chronic pain by a person who doesn't experience any themselves is a difficult and trying situation. They just can't relate, nor can friends, etc. The government is putting all kinds of pressure on the medical community to limit pain meds - I understand that, but my situation is very different from someone who is looking for oxycodone or vicodin with no history of any trauma or degenerative disease. My meds are specifically slow release and kept in a safe to make sure nothing happens to them. I've never, in over a decade failed a drug screen. Never requested an early prescription. But my insurance co recently decided that they wouldn't pay for my full script, and my doc is trying to sell me CBD oil (the non THC type is the only legal kind here) to replace the meds - and of course, insurance won't pay for that in any case.\n\nI feel for anyone who is going through this situation. It really sucks the life out of you.", "'Physical' pain is actually super weird and complicated. It is probably best to think of 'pain' as a broad term which includes a wide range of uncomfortable and distressing physical feelings. Pain is not simply a mechanical process where the input is directly related to the output. Pain stimuli is also filtered through the brain's subconscious and conscious controls for what stimuli become apparent to the person and how intensely that experience is represented to the person.\n\nYou ever see someone hurt themselves but not really react proportionally until made aware of how bad their injury is? That's weird right? Why would their pain tolerance change so dramatically for the same injury with the input of additional information?\n\nThere are biological components for higher and lower pain tolerance, for example people could have different levels of sensitivity in the sensory cells ([nociceptors](_URL_6_)). Hormones can alter pain tolerance too, for example adrenaline and oxytocin. There can also be [psychological factors](_URL_6_) which heighten or lower reported pain experience. \n\nIt can vary for the location of pain (e.g. a broken finger vs a broken a rib), type of pain (small concise location vs large area), source for pain (injury vs chronic condition, burn vs blunt force trauma, etc), familiarity with the pain source (previous experience with same injury), expectation base lines for pain intensity (being told something will hurt a lot vs told it will only hurt a little), use of pain mitigation strategies (e.g. swearing, no really, [swearing can help](_URL_6_)), acceptability for expressing or admitting to pain and many more I have not listed.\n\nThere are also disorders which result in [no sense of physical pain](_URL_6_). Imagine trying to live your life without knowing if something is hot?\n\nThere has been an attempt to try and incorporate these multiple factors in to pain experience to a single model - [the biopsychosocial model](_URL_6_). This is a particularly useful approach to pain for [athletes and people who exercise](_URL_6_). Using this model people can avoid unnecessarily catastrophizing a pain experience, avoid unnecessarily limiting exercise and activity they need to achieve their goals and even potentially avoiding questionable medical intervention (e.g. surgery or injections) based on outdated pain and injury theory.", "Everyone's neurochemistry is different. What one person experiences is not equivalent to everyone else.\n\nHaving taken all of the serotonin drugs I can say the following:\n\n & #x200B;\n\nThere are people whose persona is based on being either low or high serotonin based, or \"balanced\". It was quite the epiphany, really: once I realized \"I'm not reacting the same on this chemical emotionally\" it became evident that \"oh... that's why \\*that\\* person is that way, and this other person is \\*that\\* way\". The contrast was obvious. Some people can handle things a certain way not by magic or \"training\", some other bs - it's because their neurochemistry makes them that way.\n\n Stub my toe not on an SSRI: instantly hurts very bad, but then gets increasingly worse for the next minute. \n\n On an SSRI: instantly hurts, fades away almost immediately. The inability to \\*not focus on the pain\\* makes it a feedback loop that makes it worse and worse. \n\n So when I see X -Gamers slam hard, and then get back up - I now know kind of how that works. They're on the opposite end of the spectrum from a pain-management standpoint; hence their ability to continue to do what they do after falling, breaking bones repeatedly. They are \"tougher\" not because they can withstand pain more, but because \\*they're not perceiving it as much\\*. \n\n It also explains what to me seems like peculiar behavior, \"advice\" to people \"just get over it\", \"suck it up\", \"learn to take the pain\", blah blah blah. No, it doesn't work like that. To someone with a high threshold and tolerance, it may \\*seem\\* to be like that, but again - that's completely ignoring people's brains are different.", "Here's the \"like I'm 5\" version.\n\nPain is personal. If not showing how much x thing hurts is what you grew up with then you'll have a high tolerance. If getting upset after experiencing pain is normal for your life you'll likely have a low tolerance.\n\nTolerance, mostly, is how much you're willing to complain/express pain.\n\nHere's the more adult version:\n\nThe experience of pain, except in niche cases where biology heavily involved, is primarily a learned response to stimuli. Pain is a combination of a biological reaction (nerve endings firing) and your psychological response to threatening stimuli.\n\nIf you have a powerful psychological response to threatening stimuli you're likely to have a dramatically lower \"pain tolerance\" because your brain over-reacts & treats pain as more threatening than it is. This can be measuring in brain activation of \"pain centers\" e.g. stimulation in the brain. \n\nYou can even see these areas light up when imagined pain occurs e.g. someone pretends to throw something at you and you exclaim \"ow!\" before anything even hits you. In that case you won't feel pain but your brain is lighting up so you're expecting pain ironically causing you to react to it before you even know if it will hurt.\n\nCaveat: This explanation comes from an education that's now 10 years old. Correct me if I've made an error here or if new research has come out disproving this theory on pain.", "I did a paper on the addictive nature of pain in my college Abnormal Psychology course. As a dancer, I have a ridiculously high tolerance for pain and was very interested in that response myself. It was decades ago, and the only thing that stuck with me is the addict A/B response. With dance, when stretching for instance, tolerating a certain amount of pain results in gains in extensions. This might be creating an addictive cycle that makes the pain less negative and more of an indicator of progress.\n\nThe interesting juxtaposition is that my skin is EXTREmely sensitive to touch. \n\nWhen I shredded my shoulder, my doctor didn't believe me for almost a a year because I wasn't expressing a lot of pain. He was pretty contrite post-surgery because he found that the labrum was completely detached and the supraspinatus hanging by a fiber.\n\nI don't think the theory that - less sensitive nerves make you more impervious to pain - is the answer.\n\nI also read a book when my daughter was an infant about a stone age tribe that doesn't have a word for pain, because they don't see that kind of body signal as negative. They deal with it completely differently.\n\nThere must be some peer reviewed papers out there on the subject.", "People with chronic pain have the highest tolerance because they have to learn to live regular lives... take care of kids, go to work. We smile and laugh at the birthday party while looking at the clock wondering when it’s going to be cool to slink away and to get home and cry in the shower alone bc sweet baby Jesus the hot water is a relief at least while you’re in there. \n\nThe truth is nobody wants to hear about it. It’s not a comfortable topic & it’s not something you can see like a broken arm, etc and it’s too difficult to understand without experiencing so we just keep it to ourselves or our closest people. \n\nI often have no idea if I’m sick or not. I ended up in the hospital with scarlet fever and the nurse kept asking, “why didn’t you come in sooner!?” Because I didn’t get a high fever until now and that was the only way I had to know I was genuinely sick and not just my normal pain. Had strep for days without a clue. \n\nBut mostly I just wanted to add to this thread that I recently started ldn and am having good results. I think it’s something anyone with chronic illness/pain/autoimmune issues should look into.", "MMA fighter (former fighter, trained 10 years and now I'm training alone) here. I want to add that pain tolerance can be improved DRASTICALLY if you go under certain conditions. I've been hit since around the age of 10, and I can see a lot of differences between my current pain tolerance and my pain tolerance 5 years ago or other people's tolerances.\n\nI can literally burn myself with a flaming metal and resist it (it's effective in treating wounds, but most people just can't do it). I also torn down ligaments during fights and ignored it for too long because I couldn't understand it wasn't a normal \"pain of training\". My right thumb is dislocated because of that.", "To put a spiritual spin on it, there's a parable in Buddhism related to this idea:\n\nBuddha once asked a student, “If a person is struck by an arrow, is it painful?”\n\nThe student replied , “It is.”\n\nBuddha then asked, “If the person is struck by a second arrow, is that even more painful?”\n\nThe student replied, “It is.”\n\nBuddha then explained, “In life, we cannot always control the first arrow, however, the second arrow is our reaction to the first. With the second arrow comes the possibility of choice.”", "I don’t know... and I’m not qualified in any way to say... but could it be that the way pain is experienced is psychological? \n\nThat would make logical sense to me... some people can choose to block out certain pains in a psychological way, choose to ignore it if you will\n\nThat means it may it possible to train the mind in a Pavlovian way to respond to pain stimuli in a way that advantageous to you... I.e learn to have a higher pain threshold", "I don't know about all this chemical stuff, but a doctor once told me (while I was sitting around after a moped wreck I had) that pain tolerance is partly chemical, but mostly \"eh, I've had worse\". Said the 1-10 pain scale rates the patient more than it rates a condition, and it effects a doctors bedside more than it does the treatment.", "Hey. If there isn't a chronic pain site already on here, someone should start one! Sometimes you need advice but most times, it's just nice being able to say \"yeah, I know that feeling\" and not feeling so alone in your pain.", "[_URL_7_](_URL_7_) \n\nlorimer moseley explains it better than me. so watch him.", "There are two things to keep in mind. 1. The signal of pain being sent to the brain and 2. the interpretation of the brain of said signal. These are general rules of how the body interprets the world. \n\nAn example if this would be flexibility. You will stretch to the point of pain. It's the body's way of protecting itself from harm. To increase flexibility is to stretch repeatedly until the body is retrain or relearn what a safe limit is and keep increasing those limits. When that happens the body will perceive pain when you are stretching at the new limit. This also happens with combat sports where they increase their tolerance as the brain reinterprets what is safe. If you truly didn't feel anything at all then you would suffer damage like in leprosy and diabetes. People with these diseases will suffer damage because they lose sensation due to nerve damage and they may have a cut or develop ulcers in the skin from lack of feel. By the way, people who \"enjoy\" pain produce more endorphins, which are the body's natural pain killers, than the normal population. They don't so much enjoy pain but the high that comes when the endorphins kick in.", "As an MD, I'd just like to state that people need to understand just how dangerous and harmful it is to take opioid pain meds on a long term basis. This doesn't need to involve addiction, just taking them chronically. You have no idea the damage you are doing to yourself and the path you are putting yourself on. I see so many patients who do not understand this at all. They think it's harmless. You are literally re-wiring the way your mind and body functions.", "There was a theory I learned back in college but it’s mostly lost to me RE: pain receptors. Apparently it’s shared with sensation, so that’s why people rub their arm when they bang it. It actually dulls the pain either through brain (sensory) or nerve pathway overload. Can’t remember which.", "Man this is educational. I always figured everything hurts the same and some people are just more extra about it than others." ]

[ "What you're seeing is called **total internal reflection**, and it's something you learn about in physics class when you study things like lenses and optics. It all has to do with the angle between the ray of light and the surface of the water.\n\nLet's pretend the water is perfectly horizontal, and doesn't have any waves or ripples on its surface. When a ray of light goes from the air into the water, the light is going to change direction. This change in direction is called *refraction*, and we say the light *refracts*.\n\nWhen the light refracts, it always bends in a very predictable way. If the light hits the surface of the water at an angle, the water will always bend the light so that it is traveling closer to straight up and down. So, light comes in mostly sideways, and then hits the water and turns downwards.\n\nIf light leaves the water, the opposite happens. If it's going mostly straight up, when it leaves the water, it turns so that it's moving more horizontally. If you're in the water and tip your light so it's going more and more sideways, eventually you're going to find a point where when the light leaves the water it's going perfectly horizontally. If you tip the light in the water further from vertical, the light \"leaving\" the water will want to bend past horizontal and go *back into the water*. In other words, the light just bounces off the underside of the surface of the water, and goes back into the water.\n\nHere's a video of a couple guys playing with lasers out on a lake demonstrating total internal reflection.\n\n_URL_0_", "When you look at a swimming pool from a really low angle -- your head a couple inches or so above the water and you're looking 5+ feet out, you notice the water reflects and acts like a mirror. But when you look straight down, perpendicular to the surface you can see clear to the bottom of the pool. The same is true in reverse. If you're underwater and the surface is still (I know this is difficult to do), but you could look straight out to the sky or if it's an indoor pool, the roof. If you look at a low angle again, you'll see the surface act like a mirror. The thing that is different is that when you're under water looking out into air, the angle where the water surface starts acting like a mirror is much bigger than the other way around. The fact that the angle is much larger added to the fact that it's difficult to get a still surface of the water when you're underneath it, makes it feel like the surface isn't see-through. You'll notice it partly is if you have goggle's on and you're looking at something just above the water -- it will just look distorted and wavy with holes of internal reflection.\n\nThe reason that the underside surface has a larger reflection angle is related to how light travels more slowly in water than in air. If you're interested in a more detailed explanation, I suggest you google \"Snell's Law\".", "It is all water, not just your pool. You can see the effect better in clear liquids with smooth surfaces. What you’re talking about is total internal reflection. It happens because of how the water filters the light and interacts with it at the border between the water and the air. The way that the light is gathered and polarized means that it can be totally reflected back from underneath at certain angles, like a mirror. The reflection of polarized light happens above surface too, but not quite like the internal reflection. That is why people out fishing often wear polarized sunglasses, since it removes the glare off the water from the topside" ]

[ "'Instantly' is relative to a preceding action, similar to 'immediately'. If something happens instantly, it happens right after the preceding action. E.g. 'I clapped my hands, and the lights instantly dimmed.' The actual act of dimming from brightness A to brightness B may take several seconds, but the word 'instantly' indicates that they did so immediately after I clapped my hands.\n\n'Instantaneously' is relative to the start of the action itself. If something happens instantaneously, it happens very quickly. E.g. 'I clapped my hands, and the lights instantaneously turned off.' There may be a slight delay before the lights turn off, but the word 'instantaneously' indicates that they did so in an instant, as opposed to, say, slowly getting dimmer until they turn off.", "As verbs, both words mean exactly the same thing - immediately, or so quickly as to be an imperceptibly small amount of time after. \n\nThe difference is that ‘instant’ can also be used as a noun, whereas ‘instantaneous’ cannot. In this case, ‘instant’ means the same as a ‘moment’, though specifically a very short one. Example: “she paused for an instant”. Instantaneous would not be a valid substitute in this sentence." ]

[ "Yellow light (warm light) looks like, and remind us of fire, which is warm and cozy.\n\nBlue light (cold light) is more like ice, which isn't as cozy.\n\nThis is why different light bring different sensations" ]

[ "The products are the same but the difference is in the service level, and therefore the price.\n\nIf you buy \"daily lenses\" and they rot after two days - you are on your own. So, the product costs a little less per lens.\n\nIf you buy \"monthly lenses\" and they rot after two days, the manufacturer is liable for injuring you and they have to pay out. So, the product costs a little more per lens. In fact, it costs almost as much more as the market will bear.\n\nBut, the products themselves, they are the same. By the way this pricing model appears all over the place.\n\nFood: fancy package or crappy package but same food inside. You can pay more to have a luxury product, and how the customer feels is very important (my kids' health is worth buying the best!)\n\nAircraft engines: Airlines don't buy the engines, they are provided on leases from the manufacturer, with service included. So you can pay one price with the power de-rated to a certain level, or pay a higher price to unlock the power. And if the pilot gives it more than 100% rated power, say in an emergency, the warranty is voided and they get charged. With the higher power version, of course the service is required more frequently, so it costs more. But, the two engines are the same equipment.", "The same difference between dishtowels and paper towels. One you use and throw away because it is cheaper and isn't made to be used more than once. The other is the same stuff, does the same thing, but you can wash it and use it again.\n\nDaily lenses aren't made to be washed. They're thinner cheaper less acceptable to harsh cleaning chemicals to get rid of your eye-gunk.\n\n*Can* you wash them? Of course! You can also use a paper towel and hang it up to try and use it again. But at some point you gotta ask yourself is that sanitary?" ]

[ "The steel wool oxidizes, effectively becoming rust. As steel requires a shitload of energy to vaporize, it pretty much doesn't produce gasses to burn, so the reaction only happens at the surface of the steel, not in the air around it. Iron oxide is far weaker in tension and shear than steel, so the integrity of the burnt wool is significantly reduced." ]

[ "Different tolerances to different climates. Some plants need warmth and sunshine all the time and others can do fine up north.", "Different climates and if we're talking naturally, the fact that a lot of areas of the world with similar climates are isolated from each other, so plants that evolved in one place couldn't spread to other places that would otherwise be suitable." ]

[ "There has been. Esperanto was designed after World War 2 to reduce the possibility of war due to miscommunication.", "After religion, language is probably the second most culturally sacred thing that most communities protect. While the idea of a universal language is not mutually exclusive to a cultural first language, this would be controversial if not absolutely opposed by many groups around the world. \n\nOne could argue that a universal language benefits or at least has the potential to improve worldwide education disparities etc etc but it would be a huge lift to get nationalistic/conservative/ethnic groups to not see that as a threat against their communities.\n\nAs a gruesome example, consider Nigeria's Boko Haram - which is violently opposed to \"western\" education especially, it appears, when taught to females. Although extreme, the thinking behind this is sadly, not uncommon.", "Attempts were made.. and ultimately one language exists which is spoken, or at least read by a big part of the human population.. it’s english... And to why there weren’t a attempt to make english, or any other language, the native language for everyone: In my opinion that simply isn’t a desire for most of the people. One reason for that could be the strong bond between language and culture. And most humans don’t really want to change his culture, or they even are afraid of a change, so they would block any attempt to change one of the two things.", "English: Am I a joke to you ?", "There's Esperanto which was developed as a universal language. \n\nBut in terms of world cooperation there are a lot of other things that also need our attention like War/Peace, the Environment, Economy, etc. \n\nLanguage also changes rapidly. The whole reason we have multiple languages is because of those natural drifts and even when you go back and look at older versions of a language its easy to see the changes in what's happened. \n\nLanguage is also an important cultural marker for people. For a long time the English either banned or supressed the Gaelic language in Ireland and Scotland in an effort to help English colonial efforts in those countries and now today you have movements aimed at reviving the language because people feel its an important part of their identity." ]

[ "Yes, it just ends up in the dump, unless they bothered sending the recyclables to recycling. Garbage doesn't randomly spread from the dump to other places, it ended up on the beach because people littered there." ]

[ "Not terribly. The Earth is going to be the main catcher of such asteroids. Despite all the pock-marks on that moon, it doesn't actually catch very many of them. It's just the craters on the moon never go away, save when swallowed by a larger crater.\n\nMicrometeorites are a bigger problem (er, rather, a large -er, more critical concern.) You can deal with them by carefully compartmentalizing your base into individual sealable units. That does add to the overall cost and weight, but odds are, you want your moon base to be modular in anycase." ]

[ "Escaping predators, showing off for mating purposes, shedding parasites can all be reasons why they leap into the air it is then down to the species and circumstances as to what is the main driver.", "There may be a number of reasons and different ones for different animals. A flying fish is more likely to try to escape predators but the same reason is less likely to apply to some giant whale.\n\nTraveling though the air can be faster or at least less energy intensives than though the water. With smarter animals it might even involve some aspect of just for fun.\n\nIt differs a lot based on what animal exactly is doing the flying.\n\nSome of the really weird ones involve squid who fly though the air via jet propulsion." ]

[ "Have you ever tried balancing a long pole or stick on its end with your hands? You have to move your hands towards the direction the stick is falling to keep it upright, and with a little practice your can do so pretty reliably, even while you walk around. \n\nNow imagine if we replace your hand with a motorized ball, and your eyes with accelerometers that can very precisely measure the angle of the stick. We can then program a computer to do exactly what you were doing with your hand, but calculate and correct for the motion of the stick tens or even hundreds of times per second. \n\nThat is basically what that robot is doing - constantly determining which direction it's starting to fall and rolling in that direction to counter the fall." ]

[ "Tears are all produced by the lacrimal (lachrymal) gland, but psychic tears (sad tears) also coincide with other bodily responses, due to their production being driven from the hypothalamus in the limbic part of the brain. - _URL_0_" ]

[ "Once you have something to lose you May begin to feel threatened by the “takers”...or something like that.", "Conservative economic policy tends to lean on the side of less taxes and less government regulation, which are good for corporations and not as much for the average person. So, once you get more wealth and get into the higher tax brackets and have more and more regulation apply to you, the more you might dislike such policy and edge toward the economic right.", "A very simplistic view is that when you are young and have nothing, the idea of sharing and equality sounds great because it may actually benefit you. When you get older and you’ve had to work your ass off to get what you have now, the thought of sharing your earnings with people who don’t want to work becomes a lot less appealing." ]

[ "In most areas, the school system is supported by local property taxes, so if it's a poor/rural area, the tax base won't be as big.", "Questions about the US are generally better in r/askanamerican.", "Unequal access to information, due to inferior resources. Doesn't matter how passionate a teacher is if they're kneecapped with an outdated cirriculum, or saddled with more students than they can give attention to.", "No national curriculum and no legal requiremnt to attent school.\n\nIn Germany e.g. you are legally required to attend school until you are 16, from there you are legally required to either continue school or be in an apprenticeship until you're 18,", "A LOT of states force school districts to do local property tax referendums to pay for, well, EVERYTHING. So, high property values = better schools. It’s the new Jim Crow." ]

[ "Thin skin can sunburn way faster. Because there is less area /depth to absorb the energy. Thin skin also has less hair to protect it." ]

[ "> ELI5: Why do the nails on my ring fingers grow faster than the other nails?\n\n\nYou're weird\n\n\nJust kidding. Most of it has to do with blood circulation. Some people's fingernails grow at different rates. Some people find that different fingernails on one hand grow at different rates . Some people find that their fingernails on one hand grow at a faster rate than those on the other hand." ]

[ "The speed of heat transfer is proportional to the difference in temperature between two objects, which means how long it takes to heat or cool something is (non-linearly) proportional to how large a temperature difference you can make between the desired temperature and the heat source/sink you're using. (It's also affected by the particular materials you're using, so trying to boil water by exposing it to hot air is a lot slower than by dropping it on an iron skillet that's the same temperature, but in household use you frequently are just heating or cooling air.)\n\nIf you're trying to boil water, you're trying to bring it to 100ºC using a flame that's probably around 2000ºC (eg, a natural gas stove). That's a difference of 1900º, which is quite large, so it goes very quickly.\n\nIf you're trying to freeze water, you're trying to bring it to 0ºC using a freezer that's probably around -18ºC. That's a difference of only 18º, so it's going to be relatively slow.\n\nIf you tried to boil water using air that was only 120º, it would also take a very long time. Similarly, if you trying to freeze water using air that was -150º, it would go much quicker. But, our household appliances don't provide those things, so we get what we get.", "I mean if you dip something in liquid nitrogen itll cool down FAST. \n\nThe problem becomes whether or not its practical. Right now it's more practical to create fire which is super good at heating things up than removing heat with our technology." ]

[ "It's essentially talk therapy for a current issue you're having where your counselor makes you categorize the issue into thoughts, actions, and emotions and then address how each of the three relate to the other until you've realized where the unhealthy aspect of the problem is and rationalized your way out of it. Its usually for anxiety disorders like ptsd, ocd, and gad where you fixate on things until you've developed negative repetitive behaviors or thoughts." ]

[ "Caffeine does a lot more than just block sleep hormone receptors. It is also a stimulant which works by forcing a fight or flight response from your body. This is why caffeine not only prevents you from getting tired but actively perks you up. The fight or flight responses are what can cause the adverse health effects. By consuming too much caffeine you force your body to redline and hold it there. This causes stress on your brain, hallucinations confusion uncontrolled muscle movement and convulsions, and your heart, irregular heartbeat chest pain and trouble breathing." ]

[ "Average litter size rounded up to the nearest even number because symmetry is easier to code for.\n\nMammals that have more babies in a litter have more nips", "We don't really know since evolution isn't a sentient entity that we can ask questions of. We can't even run double blind trials. In most cases we can't conduct experiments at all, both because of ethics and the timescales involved.\n\nThat said there are a few hypotheses.\n\nThe human body develops mostly in a mirror image. Soon after conception the embryo folds in half. The line down the middle becomes our digestive tract and the remains of the seam are visible all along the front from the attachment at the bottom of the tongue down to your taint. After that most things just develop the same way on both sides.\n\nSome mammals have more than 1 pair of mammaries but they tend to have more offspring at a time.\n\n2 breasts provide some redundancy. If an injury keeps you from having offspring that can grow up to reproduce you'll quickly lose out to gene lines that aren't as vulnerable to injury. \n\nTwins need two breasts. This one is less likely since, on humans, it's not really practical for two kids to nurse simultaneously.\n\nEvolutionary psychology has a theory that when humans shifted from primarily rear mounting mating to primarily face-to-face males were still evolved to enjoy the sight of two globes of butt. So human females evolved to have permanently enlarged mammaries (almost unheard of among other mammals) to mimic the butt. This is a kind of silly hypothesis and I haven't seen any independant support for it but I like it because it lets me talk about boobs and butts at the same time while still sounding somewhat serious.", "Because nature does not “design” everything to be just enough. We have two lungs instead of one. We have two kidneys but only need one. We’re bilaterally split, meaning we often have two of something, or when we have one, it’s often made of symmetrical parts. Two breasts can feed two children at the same time, or a mother can alternate between them for a single child.", "So one nipple doesn't take all the abuse. The breast needs time to refill with milk, as well.", "Because the human body is all about symmetry. Two eyes, arms, legs, ears, breasts, lungs, etc.", "The answer is 'because that is how humans evolved'. People can speculate as to why evolution took that path, but for the fundamental answer is just \"random mutation lead to humans having 2 breasts and that is the human that survived\".\n\nBecause for whatever reason women with 2 breasts were better at surviving than women with 1 breast or more than 2 breasts. Or maybe more accurately, the children of women with 2 breasts were better at surviving than the children of women with 1 or more than 2 breasts.\n\nAlso, for some reason almost all animals have symmetry. And at a minimum bilateral symmetry. Which means no animal would have an odd number of breasts. But again this is just a random mutation that proved to be the most likely to survive.\n\nIt makes sense that an animals that had more breasts than they did children, as the children would be more likely to survive. If they had less breasts than the number of children then some children would potentially starve. But having more breasts than needed must not have provided more of an advantage.", "At a point, the baby drains both boobs. So two boobs doesn't mean it's for two babies. Also, constant saliva on the nipple REALLY hurts! So it does give you an alternating ability. Probably also because nature likes to be a bit redundant, so if something happened to one of them, such as say said baby got front teeth and loved to surprise bite causing one to spew blood, you can swap to the other until the blood all drains out and heals. (true story - actually tossed my baby on the floor when it happened. Don't judge - it was involuntary.)", "Mammals in general have twice as many nipples as the average number of offspring that have at a time. Humans normally have a single child at a time so they have two nipples." ]

[ "Pensions and 401ks are different. \n\nPensions are paid by your employer. Every payday you make $2000 and your employer kicks in an extra $25 and when you retire you can draw off that fund that's been building since you started working there. And typically there are rules that say when you retire your pension will be at $X amount no matter what. \n\n & #x200B;\n\n401ks are paid by you. So that $2000 you make is now $1975 because its you putting up the $25 to save an invest. But if you quit the job you keep all the 401k money and can put into a new account at your next job. Also sometimes employers do match up to a certain amount in 401ks. \n\n & #x200B;\n\nYou're right that Pensions aren't supposed to run out of money but sometimes they do. Maybe the company wasn't paying into them like they should have been. 401ks are risky because since they're typically invested in the stock market there's a risk that a market crash could wipe out the funds. \n\n & #x200B;\n\nWhen you file for bankruptcy you're telling the world that you don't have the money to pay back everything you owe and in the Mine's case that includes its employees. Now its up to a court to look at what the mine does have and figure out who gets paid, what. That can mean that people do lose money in the end.", "401(k) is a newer type of retirement plan. An employee sets aside some of their salary, and their employer matches a portion (say dollar for dollar up to 5% of salary). This money is then invested in a choice of mutual funds of the employees picking. This account is held by a financial company like Merrill Lynch or Fidelity and is 100% safe from an employer going bankrupt. The worker has whatever the value of the account is when they retire. Depending on how much money the employee sets aside and how well their investments perform will determine what they have to retire on.\n\nIn the past, employers offered defined pension plans that paid X% of an employee's salary forever once they retired, depending on tenure and level with the company. These were typically paid from funds the company held in a pension fund or from operations. Often companies would borrow from pension funds when they needed capital, and sometimes that wasn't enough money for company to right the ship. So the company goes under, the pension funds might be depleted, and there is no ongoing influx of money to fund pensions going forward.", "To take money out of your 401k, you generally have to be \"separated from service\" with your employer. If the people administering the 401k plan can't verify that, because there is no one at the employer to respond to their queries about employment status, then you won't be able to take your money out. No, you can't just wave the front page of a newspaper at them as proof. The bankruptcy process and the DoL will sort it out--eventually. Until then, your assets are frozen. They have not disappeared, you just can't access them." ]

[ "The main theory is called disassociation fue to lack of stimuli.\n\nTo put it simply, your brain is designed to take in the world around you and process it. When nothing is happening your brain basically gets bored and starts acting up. The reason faces get so weird is because of the amount of information in a face, the brain is trained to care alot about faces so when things start to shift due to \"brain boredom\" a different part of your concious brain freaks out because it knows this shouldn't be happening." ]

[ "When you swirl a glass of water, then stop suddenly, the water inside keeps swirling. There's a similar sort of thing inside each of your ears. As you spin, you're swirling the water inside those structures. When you stop, the water keeps swirling, so your brain thinks that you're still spinning.\n\nIn response to that spinning, the brain 'modifies' its movements. Eg, it tries to maintain balance and posture and eye direction to counteract the spin. Which is what 'dizziness' is, more or less.\n\nYou can replicate this yourself with a spinning chair and a friend. Sit them down, spin the chair, then stop and look at their eyes. You'll see their eyes 'twitching', or shifting back and forth, left and right, very quickly. This is called nystagmus. The brain thinks it's spinning, so moves the eyes the opposite way to keep vision 'locked', but eventually the eyes go too far and 'snap' back.\n\n[Example here](_URL_0_)." ]

[ "I did a course on plant based meats in Berkeley. It was an engineering course so I’ll focus on some technical details.\n\nSo the main idea for plant-based meat (PBM) is to find a source of protein that has similar nutritional value as meat, and optimally the same taste, texture, colour and smell.\n\nA popular material for PBM is soy protein. This is because soy protein has very similar amino acids proportions to meat, so it can function as a complete protein and you won’t need amino acid supplements. Another option is a blend of wheat, peas and another plant I forgot. This also produces amino acid proportions similar to meat.\n\nFor taste and smell, there are flavouring compounds in he industry. Givaudan gave us some fake “chicken” and “beef” samples to try out, and they are remarkably similar in smell. Not so much in taste. Impossible foods uses leghaemoglobin, a protein found in legumes, to mimic the haemoglobin in blood. This makes their PBM taste “bloody”, which is actually pretty good even though it sounds gross.\n\nFor texture, there are many tricks used to mimic the muscle fibres in meat. Quorn uses a “flowing stream” to make their fungi grow Long in one direction. The fungi is naturally chewy, so it is a pretty good analogue for meat. There are other methods like a cooking device with 2 cylinders. The PBM is placed between the 2 cylinders and the outer cylinder is spun while cooking. This applies “shear force” which stretches the material and makes the plant fibres aligned in the rotating direction.\n\nFor colour, it’s pretty simple. There are many colouring additives, both natural and artificial, that turn brown when cooked. There are also other tricks like adding searing/grill marks to PBM patties so when they’re cooked they look more similar to meat.\n\nFor the course “finals” I made fake chicken nuggets. It tasted and smelled great but was really dry since PBMs don’t hold water or oils well. You need to mix solid fats like palm oil into the PBM, but those are generally unhealthy (and palm oil itself is unpopular for ecological reasons). This is probably the largest limitation for engineering PBMs.", "Broadly, there's five different families: \n\n\n* Whole or near-whole foods\n * Think tofu, tempeh, mushrooms\n * Doesn't require much advanced food processing, texture heavily dependent on physical processing (e.g.,tofu can be frozen, pressed, boiled, baked, fried, etc) and individual recipes\n * Think more meat-adjacent, as in maybe the same nutrient role and can be savory/have broadly 'meaty' flavors, but not really trying that hard to be meat\n* Basic TVP\n * Extract protein isolates from plants (typically soy, also wheat, pea, etc)\n * Shape and sometimes season or color them\n * Rehydrate for use\n * Common filler in cheap dollar-store burritos and that sort of thing\n* Engineered plant-based meat\n * Uses protein isolates (TVP), but involves a great deal more engineering - think Impossible or Beyond burger, Gardein\n * Often uses extrusion and cooking of some kind of slurry\n* Seitan\n * Wheat gluten, can be extracted by washing a whole-wheat dough with water, is mixed with water and various flavorings and then cooked\n * Cooking methods can vary - simmering or steaming are common, as are baking, frying, or combinations thereof\n * Think Field Roast brand\n* Quorn\n * Really cool fungus tech" ]

[ "Algebra deals with numbers, and formulas / equations / relationships between numbers. Calculus deals with functions, and relationships / transformations between functions.\n\nBasically, algebra is \"basic math\"; you have numbers and you have rules about what it means to add, subtract, multiply, etc. You establish equations and functions (rules that numbers must follow).\n\nThe rest of the math builds on top of this, by taking OTHER THINGS and establishing rules and relationships as if these things were numbers. Things like sets of numbers, vectors, functions, \"surfaces\", \"fields\", etc., you can define rules about how to add, subtract, and otherwise \"interact\" with them or the interaction between them. It's useful; for example geometry is about the interaction and properties of shapes and surfaces, and it's useful to have rigid logical / mathematical rules about how they interact. Because a lot of the real world objects are geometrical, and having the geometry rules helps with understanding these real world objects.\n\nSo calculus takes functions (relationships between variables) and establishes some rules about them and how they can interact.", "Basically speaking, algebra is pushing equations around so that they solve for different variables within them, kind of like puzzles. Calculus, on the other hand, is a really fancy version of finding the slope. You look for equations for the slope at any given time and can use it to talk about the shape and behavior of equations. \n\nThey are both very useful, but two separate areas entirely (although you need some algebra to be able to do much calc)", "In their broadest definitions...\n\nSuppose you take some symbols (1, 2, 3 are symbols... x, y z are other symbols), specify some rules to how they can be changed (we know 1 + 2 = 2 + 1, we decided that that's just how the + symbol works)... And use these rules to give statements that can be proved, or finding unknowns (why not just give a symbol to the unknown, and use these rules to find its value in terms of the other symbols?).\n\nAll of this comes under algebra.\n\n____________\n\nCalculus is the study of 'continuous change'. Or 'continuous varation', and how those changes accumulate.\n\nYou may know the proof where a circle is 'approximated' as a bunch of parallel rectangles (think stripes). The idea is that the area of the circle = the sum of the areas of the rectangles. But you know that at any point, a circle can never be perfectly be equal to a bunch of rectangles. No matter you 'zoom in' so to speak, you will see jagged edges. Like drawing a circle in paint gives those jagged pixels, but if you zoom out, it looks like a circle.\n\nBut this is math, so you say \"the more rectangles you use, the closer the thing you get is, to a circle. When you use infinite rectangles, you'll get a perfect circle\". ... Are you worried there's no such thing as an infinite number of circles, well there's no such thing as a perfect circle either.\n\nSo calculus studies such relationships in variation and accumulation. Algebra is very much the fabric of calculus, because at the end of the day we're using symbols and defining how they can be manipulated.", "Roughly speaking calculus is about studying 'change'. Algebra can can tell you how fast the baseball pitch travelled on average, but calculus can tell you how the velocity of the ball changed and how fast it was going at any point in time. The other area that calculus concerns itself with is the area under a curve. Algebra can tell you the area of well known geometric shapes, but it cannot answer those questions for complex shapes. Algebra is the rudimentary math for calculus however, you will be performing algebra to solve equations in calculus." ]

[ "Lots and lots of reasons. But ELI5. Muscles get stiff because they get used to being short and all the fibres get tighter and closer together. It can also be because of literal knots in the muscle. Imagine you cut a piece of string in half, to make it whole you have to tie a knot in it. The string is shorter but it’s whole. These are knots and there can be thousands. Thanks to healing and massage those cuts can be healed to normal. \n\nPain when stretching is normally due to excessive tearing. It’s your body screaming at you to stop. It feels good because of other reasons that I’m not clear on.", "It is rarely muscle fibers that are the issue. For most of us it is the facia that runs through the muscles that becomes inflexible and inflamed. This prevents the muscle fibers from contracting and stretching as they are designed to do. \nAs for feeling good after stretches (done properly), you have ‘freed’ those fibers and lessened the inflammation in the area.", "NASM Certified Trainer here, the ELIF simple explanation for the stretching would be: it feels good when loosening (getting the knots out) or prepping the muscles for activity. It can often hurt when you are trying to become more flexible because when you push your muscles past it's normal range your body has 2 alarms. The first will try to resist and bring the muscle back to avoid injury (this is where it hurts) but after 30 seconds some complicated process happens and the second alarm will tell the body to relax and loosen up to avoid injury. \n\nSo make sure to hold your stretches for 30second!:)" ]

[ "Plaque is a thin layer of bacteria eating the sugars in your mouth. \n\nIt is linked to diet generally. More sugar = more plaque. \n\nI think mouthwash just kills the bacteria. I don't think it washes away plaque. Maybe it does idk.\n\nIf you brush/floss often enough and don't eat too much sugar, you'll be fine. If not, that plaque hardens and turns into tartar, which is the leading cause of tooth decay and other dental issues. \n\nDoubt humans are the only ones who get it, but who knows.\n\nI'm sure someone can clarify any details I missed because obviously I kept it pretty simple, and I have a shallow understanding of it.\n\nEdit: animals definitely get plaque, may be composed of different bacteria though.", "I was watching The Zoo, I think the Columbus Zoo, where one of the gorillas was having a yearly fiscal. He had plaque from eating a vegetarian diet, and his keeper had to introduce a tooth brushing regimen to help." ]

[ "It possible they would be identified & questioned but if they had reasonable explanation of how spit came to be at the scene & there was no other evidence connecting the spitter to the crime then it highly unlikely they would be considered a suspect let alone charged because the spit alone would never be enough to convict beyond reasonable doubt" ]

[ "Imagine your body has the same properties as air and I placed you into a box that you fit into perfectly. I cool you down, you condense (take up less space) and as such, your body stops touching the wall of the box and you have more room to wiggle.\n\nNow say I heat you up and you expand, you're going to start pressing up against the sides of the box as you take up more space. That pressing up against the wall as the temperature increases is where the increase in pressure comes from." ]

[ "It's actually worse than you think.\n\nThe two week notice is a common requirement for the *employee* to provide the *employer*. IE, if I am an accountant at a company and I want to gracefully quit my job to take employment somewhere else, I should provide a two week notice to my boss.\n\nBut in most, if not all, states, the *employer* has absolutely no legal obligation to give an employee a notification prior to terminating them, except for cases where it's a mass lay-off due to something like a department or factory being closed down.", "In the US, we have what is called \\*at will employment\\* . In short, you can't be forced to work. You're not a slave. You're not an indentured servant. Employment contracts that obligate you (and companies DO write these into their contracts) are legally unenforceable nation wide. If I'm working for your uncle Bob and he's all touchy-feely - yeah, I'm quitting, and I'm not going to wait 2 weeks to 4 months to get out.\n\n & #x200B;\n\nThere are a limited number of jobs in the US where you can be legally compelled to keep working, even without pay sometimes - and this is in some areas of public service such as medicine or law enforcement. Even then, the law tries to be as accommodating as possible.\n\n & #x200B;\n\nAs for 2 weeks notice - this is a common courtesy, because people want a good reference for future employment. There is no legal requirement to actually do this. In practice, many people follow the courtesy, or if you're good at your job you may even negotiate a longer period to ease transition if the employee is leaving in amicable conditions. Most people don't actually need to bother, but they don't know it or they're conservative.\n\n & #x200B;\n\nOf course, the employer does not typically grant you the same courtesy, nor does anyone expect it - they will fire you or lay you off on the spot and security will escort you to the door.\n\n & #x200B;\n\nI've been a professional for 12 years and not once gave a grace period across just a few companies. When I leave, it's immediate resignation, and it's never caused a problem. In 12 years, I can't even recall an employer I interviewed with or was hired by that asked for references.", "2 weeks notice is a courtesy. It is not a requirement.\n\n > In the UK the execs would be on at least 4 months.\n\nOr what? The beefeaters arrest them and handcuff them to their desks?" ]

[ "Your metabolism will adjust to however many calories you feed it. Up to a certain point. Extreme starvation will put the body into starvation mode or a low metabolic state. Once you've reached this mode and you start eating normally again it takes time for your body's metabolism to adjust." ]

[ "Its important to remember than a sonic boom is not an \"explosion\" or event that happens at the moment you break the sound barrier. This seems to be a common misunderstanding. As an aircraft travels through the air above the speed of sound, it creates a very high pressure shock wave that trails behind it in a cone shape, like the wake on a ship. This \"cone\" is dragged along as it flies. At some distance behind the aircraft, this cone shaped shock wave will touch the ground, just like the wake on a ship eventually reaches the shoreline. The people on the ground at this spot will hear a \"boom\" as the wave passes over them. That is a sonic boom. As the wave continues to pass over the ground, anyone it passes will hear the sonic boom. If the plane flew over the entire United States at supersonic speeds, then everyone underneath the aircraft across the entire US would hear the boom as the wave passes their location.\n\nIt's not a singular moment that happens one time. It's a constant event signaled by the movement of the shock wave being dragged along the ground, over the listeners.", "When an object move fast enough through the air (bullet, fighter jet) it have to push all the air molecules in front out of the way\n\nAs it get faster & faster the air molecules can't move out of the way fast enough so they start to compress (stack up against each other) into high pressure\n\nOnce the pressure get high enough the air molecules eventually get out of the way of the object & that high pressure air explodes outwards to low pressure which create a shockwave of air pressure that radiates outwards from that explosion point" ]

[ "Yes and no. \n\nYes because anyone can get diabetes. There are multiple types. Type 1, also known as Juvenile Diabetes because it normally develops in children, is when your immune system attacks the insulin producing cells in the pancreas. Type 1 diabetics will need to inject insulin for the rest of their life. \n\nType 2 diabetes is when your body becomes resistant to the insulin your body still produces. Type 2 diabetes is normally associated with obesity and sedentary lifestyles, but it can affect nearly anyone. \n\nThere are other types, gestational diabetes, LADA, etc., those are the two big ones. \n\nAs an anecdote, I was diagnosed with Type 1 shortly after my 26th birthday. I was in the military, and in the best shape of my life. When I went through the diabetic education classes, I was the only Type 1 in attendance. The others were Type 2. Some of those guys were fitter than I was and they still developed an insulin resistance. \n\nSo to answer your question in a roundabout way: yes you can get diabetes if you eat sugar daily. You can also get diabetes if you only ate lettuce and celery.", "Essentially, no.\n\nThere is no evidence that sugar itself directly causes either type 1 or 2 diabetes. However, excess sugar can cause weight gain, and obesity does increase your risk of things like heart disease, cardiovascular problems, and diabetes.\n\nIf you maintain a healthy weight and consume a balanced diet, the risks of a relatively higher sugar-intake are mitigated heavily. Just remember to brush your teeth." ]

[ "It's both. The noodles are deep-fried prior to being packaged which makes them high in calories and saturated fat. The season packets use a ton of a salt because it's an easy way to enhance the flavor for cheap. Both are bad independently, so together they are worse.\n\nDon't believe the msg hype, unless you have a particular sensitivity to it, it's perfect fine. Here is one article, but there are plenty of science-backed research and studies into this: _URL_0_" ]

[ "The *Latin* alphabet and the *Cyrillic* alphabet are both based very heavily on the *Greek* alphabet. \n\nWhich is why \"a\" (alpha) is the same in all three, and why \"gamma\" is a г or \"rho\" (Р) are the same in Cyrillic and Greek.\n\nHistorically, Slavs adopted a form of Greek Orthodoxy (one major branch of Christianity), but the Greek alphabet wasn't enough to express all of the sounds in the Slavic language so they had to create new ones at times, which is roughly how the Cyrillic alphabet came to be.", "Both the Cyrillic and Latin scripts are derived from Greek, but changed over time in different ways. For example, Gamma (Γ γ), changed to (G g) in Latin script, but (Г г) in Cyrillic. Many sounds are the same because they retained their sound values from the parent script.", "To complement what others have said, the question can be extrapolated to \"why don't we just use a single alphabet for every language? Wouldn't that be simpler?\"\n\nThe answer, as you can see, is that even in ancient times people wanted to have their own alphabet or system of writing to represent the sounds of their own language, which don't exist in another language.\n\n\"But the B sound is the same in all languages!\" Actually, this other tribe here says that their B is slightly different, so they want a different letter for it, and so they create or modify an existing letter to represent the sound they want. And so on.\n\nPeople think they know better, and create letters specifically to match their language. This is complicated by the fact that languages change through time, so the sounds that were originally represented by a letter, no longer correspond to it; a single letter can have different sounds, depending on grammatical rules, dialects, and whatever. For example, in English the letter \"A\" is not always pronounced the same; same with the letter \"E\", or \"I\", or basically any vowel." ]

[ "X-rays are effected by dense substances like bone so they are clearly defined on X-rays. MRI or Magnetic Resonance Imagers work by vibrating molecules under a powerful magnetic force show entirely different views of the body - _URL_0_", "For the most part x-ray photons pass easily through the muscle whereas passing through the bone is much harder so that the areas that show up white or transparent on an x-ray are those that werent showered with photons alot.\nAn MRI on the other hand measures the relaxation of an excited spin of hydrogen atoms and depending on how much water there is in a certain tissue we can determine its type. Seeing that muscles are largely comprised of water they will show up with MRI." ]

[ "Water really likes to stick to things. When you pour at an angle, the force of gravity is more than the sticking force, so it just falls. But when you tip it just a little, the water will pour over and cling to the surface, and hold on as long as it can." ]

[ "Not really... Unless you're using improper form (thus putting extra stress on your spine instead of your muscles and joints), lifting too much for your ability level, or are pushing your body to the extreme.", "It doesn't if you exercise properly. In many cases bad exercise form leads to lower back injuries as it is along with the shoulders the most tender area." ]

[ "Supportability\n\nNTFS is only semi-supported in operating systems other than Windows. Linux and BSD have a free and open-source NTFS driver, called NTFS-3G, with both read and write functionality. macOS comes with read-only support for NTFS; its disabled-by-default write support for NTFS is unstable.", "NTFS caches files (EDIT: This seems disabled by default for removeable drives but can be enabled by the user) for writing instead of writing them instantly like FAT32. This has some benefits but also runs the risk of data corruption if the device is removed before the system finishes writing that cached data. \n\nFAT32 doesn't use caching so it's always safe to remove the drive as soon as the system reports the data is copied, most users tend to simply pull USB drives from the computer without telling the computer to \"remove\" the device (which forces the system to write any cached to the drive then notify the user it's safe to remove). \n\nAlso NTFS is a Windows-specific format (supported by most modern OSs, but not by all legacy systems), FAT32 is older and has wider adoption than NTFS meaning it works on more computers. There's a newer format called exFAT that is supported on modern systems which can support files over 4GB (and has other improvements over FAT32), but it's not supported on legacy systems. \n\nSo in short: NTFS isn't as well suited for removeable devices as FAT32, and FAT32 is more widely compatible with various systems, so it's the default." ]

[ "It's a completely different process. Each has unique artifacts that the other simply can't reproduce. It's also a function of the cinematographer, who may or may not choose to use the media's artifacts for artistic reasons.\n\n35mm film can exist with several different aspect ratios, through the use of special projection lenses, but most digital projector owners don't want to have special glass for movies in ultra-widescreen formats, so they might choose to cut the edges off.\n\nDepending on the camera, each 35mm film frame is exposed for about 1/30^th of a second. This means 24/30^ths of the time the frame is recording and 6/30^ths of each second is used moving the film forward a frame. Digital cameras can come much closer to 1/24^th of a second exposure for each frame, which can minimize blur edge separation in fast-moving objects. This requires very careful lighting control, and unless it's important the cinematographer is likely to use variable exposure time to shoot with the available light, which increases blur edge separation.\n\nMost digital theater projectors are 2K (2048x1080), just a little better than 1080P HDTV (1920x1080). Extra-nice digital theaters are 4K (4096x2160). Basic 35mm film (24mm wide image) is about 3500x1890, 70mm Super PanaVision is about 6900x3000, and 70mm IMAX is 9300x6500. If you look at best-digital vs worst-film, it's about the same, but otherwise film is just a lot more pixels.\n\nFilm can project more colors over a wider range than digital projectors. Particularly in dark scenes, which for instance explains a lot about why some fans with their flat panel TVs set for \"normal TV\" hated recent Game of Thrones scenes while others with their neighbors with their TVs set for \"cinema mode\" lived it. This should be less of an issue in a professionally run theater, which should calibrate carefully for every movie, but it's another variable in the equation.\n\nTarantino is another variable. He's a film affectionato, having said many times that he'd retire if he couldn't shoot on film and have viewers see projected film. He's the sort of director most likely to put a cinematographer in a situation where the unique properties of film are required to get the shot." ]

[ "Fish have sensory organs along the sides of their body, called the lateral line, that can detect changes in water pressure. When one fish turns, it creates vibrations in the water other fish react to, maintaining their schooling pattern.", "They watch each other, and each tries to turn in the same direction as its neighbors. So when one sees something scary and turns, a \"wave\" of direction changes spreads through the group very quickly." ]

[ "When you re-heat things in a microwave, water molecules are what absorb the microwaves and receive the energy. With things like cheese, that makes the water kind of separate out and makes the cheese more 'soggy and stringy' instead of 'foamy'. Texture changes taste. \nIf you re-heat your Mac and cheese in an oven instead of a microwave, it will be much better.", "My mother used to reheat it in a frying pan with a little butter...perfect flavor, and bonus crispy parts.", "Who has leftovers of mac and cheese? 1 box = 1 serving, right?", "Ever heard of a steam oven? Not a high pressure oven, but one where there's a compartment for like half a gallon of water.\n\nYou throw in anything, and you reheat it, but not with warm air, but with steam.\n\nYou steak, cooked to perfection yesterday, will come out of the steam oven like it was freshly cooked.\n\nSame with your Mac and Cheese!", "Probably more significant than the minor issues of moisture loss already mentioned in this thread, (which only really affects texture, not taste,) pasta actually changes its chemical structure when its cooked, cooled for a time and then reheated:\n\n > cooking pasta and then cooling it down changes its structure so it becomes a form of 'resistant starch.'\n\n > Unlike carbohydrates, resistant starch resists digestion by the enzymes in our stomachs - and the sudden highs and lows of blood glucose that result from it - and instead continues travelling to the large intestine, where it acts more like dietary fibre. \n\n > This means that if you cook some pasta and let it cool down, your body will digest it like it’s fibre instead of carbohydrates.\n\nThose once delicious jones-crushing carbohydrates turn into \"resistant starch\" which tastes like old glue...\n\nYou're going to need a *lot* of extra cheese to compensate for that.", "Real Mac and cheese always tastes better the second day, so I don’t know what you’re talking about.", "Mix in a little bit of chicken stock mixed with garlic and salt and pepper, into the mac n' cheese. Then when reheating put a thin layer of colby jack on top. Its like a whole new meal!", "Good homemade stuff doesn't in my experience. If it dries out a little I just pour a little splash of milk in the bowl, heat it, stir it and it's almost as good as new", "Add some milk and put it in some foil, air fry it with some Parmesan on top. Microwaved Mac and cheese is the worst.", "I have had better results using longer reheats at 50-60%. It seems to make the buttery bits re-melt more pleasingly vs being on full blast the entire time.", "While this isn't an ELI5, this article discusses that cooling pasta turns into a \"resistant starch\" which your body then treats more like a fibre than carbs, also raising glucose levels less, reheating it was found to only increase the effects at that point. Perhaps that structural change also effects the flavor: [Reheating Your Pasta Makes It Better For You](_URL_0_)", "The mac keeps absorbing the liquid so it’s dry with no moisture to help transmit flavor. Just stir in a little milk before nuking.", "I don't know if this is that common but I will fry leftover mac & cheese in a pan with some butter and pam, tastes pretty good, then you can also grate some extra cheese in/add some bacon bits or something" ]

[ "One simple mechanism is due to blood sugar levels. \n\nMost of your body can burn sugar for fuel, or other stuff. Your brain can only use sugar (with a few exceptions).\n\nTo keep your muscles and whatnot from using up all the blood sugar and killing you, your body uses insulin as a signal for when it's ok for the rest of your body to burn sugar. If your blood sugar is low, the insulin level drops, so that the sugar in your blood is reserved for the brain. \n\nCarby, starchy foods cause a big rise in blood sugar. This causes a big rise in insulin. This causes your body to burn lots of sugar... which leads to your blood sugar getting low. Low blood sugar causes an especially ravenous type of hunger called glucoprivic hunger, which makes sense because without modern medicine, if your brain runs out of sugar, you're going to fall unconscious and then die. So your body responds by driving you to IMMEDIATELY go eat. And if what you go eat is mostly carbs, we start over again: high blood sugar, insulin, low blood sugar, ravenous eating. \n\nWhen carbs are a smaller percentage of your diet, your insulin levels don't get so high and your body doesn't burn sugar so fast (because it's got plenty of other stuff besides sugar to burn), and so your blood sugar never gets crazy low (driving you into Single-Minded Food Acquisition Mode)." ]

[ "We do not have a very strong understanding of [Delayed Onset Muscle Soreness (DOMS)](_URL_0_). The leading theory is the pain is the result of the small tears your muscles which occur during the part of movement where your muscle is contracting but lengthening (eccentric phase). Muscles can only contract (shorten) but there are parts of movements where your muscle is contracting however a load or another muscle is exerting a greater force and lengthening the muscle.\n\nThe reason you tend to experience DOMS less when you routinely exercise is what is called the \"Repeated-Bout Effect\". This is the combination of your muscles repairing the previous tears and being better adapted for the activity. Your body is also better prepared to deal with new microtears in your muscles.\n\nAs far as why is day 2 DOMS worse than day 1 DOMS - we do not know. It could be just the constant stimulation of the cells that tell our brain we should feel pain (nociceptors) and how our brain processes it. It could be the result of the repair process for the tears and a protective adaptation to try to discourage more exercise until it has better healed. Or both, or something else.", "A few reasons:\n\nForm - when you're out of practice you tend to shake a bit more and that causes more muscle tears.\n\nStabilizer muscles - these small muscles shrink pretty quickly when you don't use them.\n\nWorking out is basically tearing your muscles, then you eat food to give you the building blocks to build them back up and sleep to build them up. You can only do this so fast - but the initial \"from zero\" build is the most efficient. \n\nExceeding your limits - if your limit is a 1 mile walk and you decide to run 2 miles, you're more than doubling your previous comfort limit. After that, you'll probably only add on small amounts. \n\nMuscle \"memory\" - Your body will respond quicker as you get in shape reducing the tear from the workout.\n\nFlexibility - your tendons and muscles get stretched more in a workout than in normal daily use. You're tearing all sorts of muscles that will rebuild with more elasticity. Over time, if you stop working out, they will become stiffer and shorter again." ]