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nnpi7d | Why is shampooing the second time yields more bubbles than shampooing the first time? | I'm not sure if that's just my hair but I always wandered about this. | Chemistry | explainlikeimfive | {
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"Because the first time, you scrub all the oils and stuff, the micelles in the soap cling the the fat and just wash off. When you shampoo the second time, they cling to the water because the oil is gone. This is how they create bubbles.",
"Is it really necessary to shampoo twice then as every bottle instructions say if the first shampoo already clears away the oil dirt etc?"
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nnpnpj | you know how a phone battery after so many recharges and years of use starts to lose its ability to hold a charge, is it a concern for electric vehicles in the future and their ability to hold a charge? | I'm asking because I've seen posts and threads discussing EVs here and there and mentions of as power grids incorporate more renewable energy sources the grids will yet more efficient and thus so will the EVs. Said threads also mention how the idea is for these cars to last 10+ years but I was wondering what about the batteries? I know these cars have huge battery arrays and not the usual car battery for ICE's, but if EV is 10+ years old will the battery it came with still hold the same ability to retain a charge? Or will they discharge like an older phone battery does after many years of use? If so do these manufacturers account for eventually replacing the batteries on these EVs as part of maintenence every handful of years? | Technology | explainlikeimfive | {
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"All batteries degrade over time, and EVs are no exception, in fact even combustion engine cars need their battery replaced after a while However EV batteries are quite large and you typically never use the whole range of your car every single day, and since lithium batteries have their life counted in how many “full cycles” they get, this means they will last longer than your typical phone battery",
"Yes, all batteries, regardless of type or size, will degrade with time. However different types of batteries degrade in different ways and in different lengths of time. Batteries function via chemical reactions. When you recharge the battery you are reversing the chemical reaction to put it at it's original state. But it's not a perfect reversal. Each time you recharge, the battery loses a little efficiency. The battery's ability to maintain that efficiency varies by type. A phone battery is lithium ion. They are capable of going through about 500 recharge cycles, through normal use is about 3-5 years. An ICE car battery is lead-acid. For this type of battery the reaction pulls material off the cathode and deposits it on the anode. Recharging the battery transfers the material back. But in doing so, little crystals form on the cathode which reduce the surface area which material can be transferred back to, reducing the amount of charge it can hold. Over time, and cycles, those crystals build up until the battery is no longer useable. This can take between 3 and 10 years depending on the battery design and use. An electric vehicle battery currently uses lithium ion. Though they're likely going to move towards a new lithium iron phosphate battery. It's not as energy dense as lithium ion, so you'd need a bigger battery but they're much safer than lithium ion, non-toxic, can recharge very quickly and can last about 10-20 times longer."
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nnpv8w | If it’s 30 degrees outside, and it’s freezing inside a house, why does turning the AC to 65 degrees not warm the house? | Other | explainlikeimfive | {
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"Air conditioners work by absorbing the heat in the house into a refrigerant gas, then moving that gas outside to release the heat and condense back into a liquid. If it is a heat pump system, it can be reversed and work as your premise would indicate, but a standard air conditioner system doesn’t work that way",
"Because AC only cools air down; if you're below the set point for the AC, it won't kick on, because it doesn't *need* to kick on.",
"think of heat like water and your house like a boat. The more water in the boat the hotter the boat is. The AC would be the pump designed to get the water out of the boat. So if the boat is 95% full and you want it down to 80% full you turn on the AC pump and you pump out water till it is down to 80%. But if the boat is only 50% full of water, no matter how long you run the pump for you aren't going to get the boat up to 80%. You could, if your AC pump was powerful enough, pump all of the water out of the boat. But you could never pump enough water out of the boat to get more than you had before."
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nnry7f | What does a tree do with the extra energy it makes? | I know trees can store extra energy in sap, but what do they do when they have no more room for storage? I don't see trees getting super fat or growing insanely tall. So what to they do to stop producing too much energy? | Biology | explainlikeimfive | {
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"There are fungal networks in the ground that allow trees to share resources. It's actually very fascinating. Essentially, the trees have a symbiotic relationship with these fungi and share their resources with them and other trees through them. If you would like to learn more, here is an excellent and entertaining radiolab podcast on it. URL_0",
"Trees regulate how much energy they make by growing or shedding leaves, based on the availability of resources like sunlight and water. In temperate forests, deciduous (i.e. non-evergreen) trees grow leaves in the spring and summer when there’s more sunlight to support growth and shed them in the autumn and in periods of drought when they’re not growing as much and the leaves become more energetically costly to maintain than they’re worth. The size and shape of the leaves also plays a role."
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nnsfo9 | Why is color-blindness a male-dominated disability? | Is it like sex-determined characteristic? I know it exists in women too but way less often. | Biology | explainlikeimfive | {
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"Color blindness is like a lemonade in a bottle. Men got one bottle, women get two. It just need one bottle of no lemonade to make a man lemonadeless. But it need two bottle with no lemonade to make a woman lemonadeless. If only one bottle no lemonade, one bottle full of lemonade, that woman still got lemonade (but she gonna be a lemonadeless carrier that might give it to her offspring).",
"Red-green is passed down through the X chromosome, so when females get the XXs, they’re more likely to have the other X dominate. Men are XY, so it’ll be more prevalent. URL_0"
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nnt731 | Why is it only sometimes so difficult to get water out of our ears when other times it flows right out? | Biology | explainlikeimfive | {
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"Surface tension is at it's strongest when you can't get it out. Add more water and change the surface area to change the ability of the surface tension to hold water."
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nntbmh | What is actually happening when my ears ‘close up’ or ‘open up’? | My right ear has been closed up since a flight yesterday and was wondering- What is actually happening in there? | Biology | explainlikeimfive | {
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"There is a tiny tube that connects your mouth/throat to your inner ear. This allows air and pressure to equalize between the two regions. Without the tube the inner ear would be essentially sealed off and would become incredibly painful when there are pressure changes outside. Unfortunately sometimes when your throat is swollen, or something else blocks the tube, then it does indeed become sealed off and the pressure changes cause a lot of pain. Until that tube becomes unblocked the pressure will remain unequal and painful. So, we have certain mouth movements, like yawning, that try and force the tube open, but sometimes it doesn't work and you just need to wait until it naturally loosens up or pops open."
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nntiac | How do spiders and some insects climb up walls and along ceilings? | Biology | explainlikeimfive | {
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"They have special structures in their \"feet\" called setules which are like a feather. The central \"hair\" has lots of tiny branches that end in very sharp points. It's easy to run your fingers down a feather, away from where the bird's body was, but when you try to rub the other way the feather rib tips push against your finger. The spider's setules do this on a microscopic scale. Even polished glass has some surface texture, and the spider just pushes it's feet apart to wedge itself into surface microstructures."
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nnukb5 | Do banks owe each other cash to compensate for account-only transactions? | Economics | explainlikeimfive | {
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"You're making the mistake of thinking that cash is \"real money,\" but it isn't. Its just a convenient way to represent the real money thats stored in the computer system. To help illustrate this point, if you took every piece of physical US currency available (bills and coins), it would only total up to about a trillion dollars, while there's actually many many times that much money in everyone's bank accounts. So how does that work? For one, the treasury doesn't physically print more cash when the government increases the money supply. The Federal Reserve can transfer new money electronically to banks without it ever existing as cash. Secondly, banks can duplicate money through a process called fractional reserve banking, by loaning out money multiple times.",
"The first thing to know is that paper money, likely what you refer to as \"cash\" is a very small proportion of the money in any bank or banking system (or country for that matter). Most money in modern banking system is electronic - it only exists as numbers in a computer. No country prints out paper money equivalent of the money available in their economy. So there is no real issue to resolve here and, no, banks don't need to cart around pieces of paper from location to location. Bank A simply electronically transfers funds to Bank B and vice versa, as required. Banks do loan each other money though. The reasons for that are more complicated generally. Banks are required (by law) to maintain a certain money \"reserve\" in their accounts at the Central Bank in accordance with their deposits and loans. At certain times, banks may require more reserves and some banks have excess reserves of money. They will borrow from each other usually for very short periods (like overnight) just to maintain the required amounts."
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nnv9t6 | If reflective surfaces deflect light, and metal is reflective, then why does it get so much hotter in the sun than an all black surface? | Physics | explainlikeimfive | {
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"White metall will be cooler than black metal. What all black surface are you comparing it with?",
"Reflective metal will not be hotter than black metal. But metals in general will get hotter than say plastics because they are really good at conducting heat; metals have a bunch of electrons than hang around, they get easily excited (and heated up)and pass the energy on to other electrons and so on and get heated up all the way thru. Plastics are generally poor conductors of heat, so the top layer gets warmed, but it doesn’t warm up the ones below before it radiates the heat away."
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nnvebl | How a supplement like Melatonin works and why sometimes it doesn't do anything. | Biology | explainlikeimfive | {
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"It’s basically a hormone. Don’t think of it as “I’ll feel tired and sleep right now” you take it hours prior to that and your brain and body will tell YOU, It’s time for bed.",
"There are several options, how was your sleep Last night, did a workout?, got much screen time without blue Filter, layed in the sun till you went to Sleep, ate some food in the evening? All these are factors if/how well this Supplement will work"
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nny0ur | Why do rainbows always appear in the same spot? | Earth Science | explainlikeimfive | {
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"Rainbows aren’t physical objects with a real location in space. They’re optical phenomena that appear at specific angles relative to the Sun and your eye, as long as there are airborne water droplets somewhere along that line of sight.",
"Rainbows are caused by sunlight passing through water which separates out all the colors. So the location of the rainbow is determined by where the light source is. The rainbow is actually a big circle (Most of the circle is under the horizon). The center of that circle is always on the opposite side of you as the sun."
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nnys66 | How do yo-yos work? | Never got to actually proper use one, saw one earlier and remembered that I don't know how to use one. So, how do they work? It just, makes zero sense to me | Physics | explainlikeimfive | {
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"The string the yo-yo is actually twice as long as it looks. It is folded in half and twisted back on itself. This forms a small loop at the end of the string. When you throw the yo-yo, the unwinding of the string makes the yo-yo spin. The shaft that connects the two halves of the yo-yo together sits in the loop mentioned above. The spinning of the shaft and sitting in the end of the loop is what keeps it from coming back up right away. Higher quality yo-yos actually have a small bearing around the central shaft. The bearing lets the shaft spin while the outside of the bearing either doesn't spin or spins much more slowly. The yo-yo comes back up when the string starts to wind back around the center shaft of the yo-yo.",
"You drop yo-yo. Yo-yo picks up speed as it falls. Strings unwinds, reachs the end and it’s moving so fast it just winds itself back up",
"From a physics standpoint, the yo-yo is a delicate balance between kinetic and static friction. As stated, the yo-yo string is actually a doubled-over string where the midpoint loop has the yo-yo's axle through it. Depending on how tight the string's twist is will determine how much squeezing will be applied to the axle. As long as the yo-yo has enough rotational momentum to overcome the static friction limit to have the string \"catch\" the axle, it will continue to spin freely and slow down over time due to the kinetic friction of the axle and string rubbing together. The technique of yo-yoing comes down to having control over when the string actually catches the axle. Ideally, you want to avoid anything that will cause a shock to the string -- bouncing, snapback, etc. The reason for this is that any slack you give to the end of the string allows for the friction to take effect and catch back on the axle. Once enough of the string is wrapped around the axle, it will be enough to keep the string in place and start the yo-yo winding back up. In order to get a good long spin going, a lot of technique is required to prevent the bounce once the string is unwound. Imagine that you're in an elevator that's crashing down to ground floor. It's like trying to time a jump right before it hits the ground, so that you minimize the actual impact felt. That's what's happening to the string as the yo-yo unwinds -- once it reaches the end of the winding, the yo-yo stops falling immediately, and will bounce back from hitting the end of the string's slack. & nbsp; At least, that's how classic yo-yo's work, with no extra mechanics involved. There are also mechanical-assist yo-yo's which have a centrifugal clutch. These have weights that are held near the center with springs. Once the yo-yo is spinning fast enough, the weights will push against the springs and move outward, which releases the axle and allows it to spin freely on bearings. This means that even if you have a bounce or snap, as long as the axle is free, it's not going to catch the string. This allows you to get *really* fast spins going, as well as have them last a *long* time since there's a lot less friction involved."
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nnysi1 | why homemade cleaning solutions that use baking soda AND vinegar work, don’t they just neutralize each other? | Chemistry | explainlikeimfive | {
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"They don't work. When cleaning use one or the other, never both. Those make good cleaning agents specifically because they are reactive. When you mix them all you are doing is reducing their reactivity and therefore the effectiveness.",
"How about we start listing things that DO work that may be niche :-) -Ammonia on grease -Goofoff on tar -Orange oil on thermal compounds -Alcohol on oil -Nature's miracle enzyme spray on fabrics for all bodily fluids -Simple green on smoke from fire/bbq and slimey mold on pavers -Vinegar on water kettle and other calcium/hard water deposits -Vinegar for grout haze on tiles that just got put down -Magic eraser on latex wall paint that had something leave a mark -Polishing paste/baking soda for burned-on glass stove stains -Copper spray for black mold -Shower foaming spray for inside of windshield -Armorall car fabric wipes for arm rests and steering wheel Edited below with additional stuff: -wet baby wipes for small droplet splatter on bathroom cabinets",
"Ime they don't do anything, for exactly the reason you said. I think people think they're doing something because they see the reaction and feel the fizz must mean it's working. It's never cleaned a thing for me. Give me actual cleaning supplies.",
"The two chemicals combined do a lot of fizzing and bubbling which I suppose may have some sort of physical benefit but I doubt it. The resulting chemical is sodium acetate which basically is pretty much useless when it comes to cleaning. The other one that gets me is when people specify original blue Dawn the essential dish detergent to use in a cleaning formula, as though nobody else has been able to duplicate their chemical formula in 30 or 40 years that stuff has been around"
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nnz7nm | When you accidentally inhale something, like water or food, and you cough it mostly up and are fine, how does the rest get out of your lungs and how do you not get pneumonia? | Biology | explainlikeimfive | {
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"Your airways are all covered with little \"finger-like projections\" called cilia. Their entire job is to grab onto junk that doesn't belong and scoot it back up and out until you can cough it out. Things that don't get pushed out like this get absorbed, ie, water, or attacked and eaten up by the many immune cells that live in your lungs. For pneumonia to occur, you usually need a much larger amount of food or fluid to get deeper in the lungs than most people will achieve with regular choking. More likely, people who get pneumonia already have a respiratory infection interfering with a normal immune response, which allows bacteria to set up shop and go wild 🎉🎉 Edit: Thank you for awards! 😮 Wow! ☺️",
"So I'm a radiologist. One of the tests I do has lots of names but the most straightforward is \"video swallow\" which I perform with a speech pathologist. They mix up different liquids and foods with a material called barium sulfate that shows up on X rays. You eat and drink them while I take like \"video style\" low dose x rays called fluoroscopy. What we we are looking for is making sure food goes down the right pipe. Your windpipe (trachea) is in front of your food pipe (esophagus) and the windpipe has a little flap of tissue (epiglottis) that covers it when you swallow to direct food back to esophagus. Now, sometimes your swallow muscles are paralyzed or weak. This could be from a stoke or other neurologic condition or radiation/surgery. This causes liquid or food to get under that flap and down the windpipe. Sometimes the people hack and cough (as you do when it goes down the wrong pipe) but often they may not even notice if they have a neurologic condition. This food going down the wrong pipe and beyond the vocal cords is called aspiration. The reason I bring this up is because even when people aspirate, it's a small fraction of what they ingest. Most still goes back. And your body does have defenses like mucous and inflammatory cells to protect your lungs. So a little tea or mashed potatoes slipping past once a year isn't going go to do that much. However, if it's happening with every bite or drink every meal them that DOES cause bad pneumonias. Also, when a healthy person aspirates and hacks and coughs, you're actually clearing out a lot of that material that went the wrong way before it's past the cords. Maybe a drop or so falls but that causes such a reaction you protect yourself. Note, this is a very different process to aspirated foreign bodies like pieces of a toy or hotdogs with children or when someone \"can't breath\" and needs the heimlich. If you or someone you know is worried that something substantial was aspirated, seek medical attention.",
"Your lungs are full of mucous. There are little hairs in your airways that push the mucous out, which picks up most of the basteria and liquid you might swallow. If you get water actually in your lungs, you can only hope to cough it out. It will evaporate over time too, but you'll have less lung capacity in the meantime and be at higher risk of pneumonia. If it's not water, it may stay in your lungs forever.",
"If one maintains proper oral hygiene the risk of pneumonia upon aspiration of water is virtually zero. The lungs are moist. So unless the water ingested picks up a bunch of nasty bacteria in the mouth on it’s way toward the trachea it’s not a big deal. When people suffer even severe dysphagia (aka: getting stuff “down the wrong pipe”) it’s not uncommon to implement a “free water protocol” when they are otherwise encouraged to avoid eating or drinking due to a high risk of aspiration.",
"The choking or “gag reflex” will get triggered when the food is still roughly in the throat area. The food would still have to go all the way down food pipe/trachea which is quite long way before reaching the lung tissue, and would be coughed up by a healthy individual before then. Some diseases affect this ability though.",
"just as a side point and I see it all the time. you should never throw peanuts in the air and catch them in your mouth because if they go down the wrong way and into your lungs, you may well cough it back up but the peanut oil will soak into the lung membrane like blotting paper and kill that part"
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nnzkbu | Why does internet upload and download speeds differ? Why is one faster if it's just a different direction? | Technology | explainlikeimfive | {
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"For fiber optic there's actually no difference. But otherwise, it's because there's a physical limit to the bandwidth in the cable. Most people download way more than they actually upload, so the systems are designed around using more of that bandwidth for giving them more room to download with. Best analogy I can think of is a four lane highway going into a city during rush hour. More people are trying to get *into* the city to get to work, so the traffic managers open up 3 lanes going in and only keep the 4th lane for outbound traffic, since there are fewer people using it."
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nnzs26 | How do marketing organizations measure or otherwise 'know' what the true influence is of social media influencers? The number of followers seems like an incredibly crude metric that may not get at actual influence... | Other | explainlikeimfive | {
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"The goal of advertising is no longer as direct as any sort of 1:1 advertisement to sale. The general goal of modern advertising is to increase the share of a product in your mind. Assuming you are a guy you don't use tampons for example. But if your girlfriend asked you to go buy her some I bet you would buy one of the major brands because that feels like the \"default\" and what is \"normal\" and so even though that is a product you might not ever personally need you have carved out a definition of what is acceptable in that space. stuff like influencers are just meant to get good positive associations in your head. In some form that will someday translate to sales, but they don't expect anything like you running out to buy the product right when you hear a youtube say it, they expect your list of options to narrow down a bit. So when you do need to buy a website your mental list of possibilities will have squarespace on it because you heard every single podcast in the last 5 years say it a trillion times. And like, wendy's sassy twitter isn't there to make you run out and buy cheeseburger, it's there to make you like wendy's and think of it sort of generally positively.",
"Sites like google know how many people click through ads directly from the influencers sites like Instagram. The influencers get offered brand deals which usually involve a custom url or code. And they can see the quality of their followers."
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no0dxj | What are Keynesian economics and Austrian Economics? | Economics | explainlikeimfive | {
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"Keynesian economics is called that because it refers to the ideas John Maynard Keynes had about how national economies work. Austrian economics is called that because the people who originally came up with it were Austrian. Keynes (pronounced Kanes) believed that free markets were not the solution to everything, and that governments could spend their way out of recessions and depressions. His school is still capitalist, but with direct government intervention. Later followers of the Austrian school led to the development of the anti-regulation, governments must keep their hands off the economy that was later morphed into Reaganomics. This libertarian philosophy of economics (“lassez-faire” or “anything goes”) underpins almost all Republican Party thought, essentially since Reagan won the argument over Bush, who famously called Reaganomics “voodoo economics.” An important “popular” (here, meaning not insufferably academic) book in the Austrian school is The Road to Serfdom, by Friedrich A. Hayek. There is a third school, led by University of Chicago economist Milton Friedman. He and his “Chicago School” comrades were strongly opposed to social programs like Social Security or Nationalized Healthcare. They are the current dominant force in American economic policy, specifically the way that the “Chicago School” views on unemployment and inflation are the actual policy of the Federal Reserve Bank. This school believes that everyone having a job (“full employment”) would be bad for the economy because it believes that full employment would lead to runaway inflation. Instead they posit that there is a “natural” rate of unemployment. They have issued various predictions over the years about what that natural unemployment number is, and although inflation has remained stable for years (really until just now) and unemployment has consistently been well under this “natural rate” their ideas are still accepted by so-called mainstream economics. Finally, recently a new competing theory has emerged about how all this works, called Modern Monetary Theory. This is closely associated with American “left-wing” politics and specifically with Bernie Sanders and the 21st century progressives. Stephanie Kelton is the economist most closely associated with this theory, and her book The Deficit Myth is a well-written mass market introduction to Modern Monetary Theory. Both the Austrian school and the Chicago school are strongly opposed to the economic theories of Karl Marx. Any errors are mine and unintentional.",
"Keynesians believe that you can use monetary or regulatory policy to more positively influence the overall direction of the market in aggregate over time than free markets left to their own devices. Austrians believe that economists should base policies on human psychology and subjective individual determination of value rather than statistics and game theory. Keynesians believe economic equilibrium is a universal state. Austrians believe it's a state of mind."
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no18jm | Why does water seem to get bluer the warmer or colder it gets, like in the Caribbean or the Arctic? | Chemistry | explainlikeimfive | {
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"The really turquoise blue water comes from seeing things under it, such as white sand, ice, etc. Very deep water is a very dark blue colour. And many areas you may be thinking of have very sharp drops into the water and go rapidly to deep water and/or they have dark rock or dark sand for a bottom. The Caribbean has large shelf’s of very white sand so has large areas of very light water. But also, opaque water that has a lot of sediment also can be dark as it’s not as transparent. Equatorial water tends to be very transparent and so bottoms show better, while areas like the Pacific Northwest are full of life and have lots of sediment.",
"Eva01beast has the best answer so far, but it does leave a few things out. The microscopic stuff that lives in water that we can't see also colors it. There are lots of places where the water is more or less clear because of temperature or salinity. Blue Lake in Oregon is extremely cold and you can see 300' to the bottom because nothing lives in it. The gulf is much more saline than most oceans and that causes some of the clarity as well as the general shallowness."
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no1fmj | Why do we get irritable when hungry ? | Biology | explainlikeimfive | {
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"It has something to do with blood-glucose levels. When you go a long time without food the blood-glucose levels sink and your brain perceives it as life threatening. Also when your blood-glucose levels are low, the body will send out hormones to try to increase glucose levels. Those hormones can also make you feel stressed.",
"Successful life-forms evolve reflex behaviours where they react to states of potential harm in ways which tend to act to reduce the potential harm. Lacking nutrients is an example of such a state of potential harm. A state of irritation is a state where the life-form is energized to act in certain ways (e.g. foraging for food, escaping a hostile situation) which are likely to reduce or avoid the potential harm. By contrast, a state of quiescence or passivity is a state where the life-form is \"de-energised\". It comes about as a reflex reaction to certain conditions in which being quiet, still and/or saving energy tend to reduce or avoid the potential harm. Sadly the reflex behaviors of humans are often not well-tuned to their modern societal environment and this often leads to negative outcomes. For example, getting irrtated at, and abusive to, the staff in a restaurant generally does not mean that your hunger will be satisfied more quickly. For a more advanced understanding look up the term homeostasis."
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no1y94 | if you picked a scab over and over again each time it formed, how would a cut ever heal? Would you have this wound forever or would it heal eventually regardless if you kept ripping off the scab? | Biology | explainlikeimfive | {
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"According to the experiments preformed by a younger me you need to sleep eventually and that’s when it heals over",
"The cut would eventually heal if it didn't get infected, but you would end up with a rather extreme scar.",
"The short answer...yes. Why? Wounds heal from healthy tissue outwards (generally). This healing tissue (often called granulation) is interwoven into existing tissue and it doesn't peel off easily. Scar tissue is seriously tough stuff, much tougher than the skin and tissues around it. The scab you peel is an accumulation of dead skin, intermediate healing and protective tissues and dried blood. Part of my practice as a Community Paramedic is advanced wound care, and quite often I end up removing scabs to promote tissue growth and manage infection.",
"I've tried this. For a small, 10mm dia. scab on my forearm, I kept pulling off the scab as soon as it was solid enough. But each time the scab that formed next was always smaller. I think by the time the scab is solid enough to pull off the outer edges of the wound have fully healed. Or are skin-like, not scab-like. I was gonna ask: does anyone eat their scabs? But then thought it too gross.",
"It just slowly turns into scar tissue and encloses. The pickable part gets smaller and smaller and you're left with a scab sized scar. Mosquitos LOVE ME. One time I was sitting outside with a friend. Same sort of clothing and everything, same location. I got 17 mosquito bites JUST ON ONE OF MY ANKLES. He had like 5 total all over his body. Coincidentally mosquito bites itch for weeks for me. They don't stop even after it's a scab and I've picked it. I still wake up just rubbing it fuckin raw. As an adult I try to stay away from summer evenings outside but as a kid I would have scabs all over my legs and arms every summer. THEY JUST NEVER STOP ITCHING"
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no2ddo | How elemental mercury can be a vapor at room temperature. | I'm not in any sort of dangerous situation involving mercury, but I'm just wondering how this is a thing. On one hand I see [various sources]( URL_0 ) stating that mercury at room temperature can turn into and "odorless colorless gas" but I don't see how that is possible if mercury's vaporization point is suppose to be 356 degrees Celsius. Can you help me? | Earth Science | explainlikeimfive | {
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"Water's vaporization point, AKA its boiling point, is 100 & deg;C but that doesn't stop it from evaporating at room temperature. Mercury is the same. The vaporization point is the temperature above which the substance must all be a vapor.",
"Every liquid has a vapor pressure that changes with temperature. What this means is that no matter what, the molecules in your liquid are trying to push off and escape into the outside world, and some of them succeed. So if you have a glass of water, there will always be water vapor in the air around it. The vapor pressure determines how much escapes to become a gas, but it will always be some amount. The same applies to liquid mercury",
"Temperature is the *average* speed of all particles in a substance. The particles are all banging around off each other. At any time, there will be some that are much slower and some much faster than this average. In a liquid, some of these faster ones will be going fast enough to fly off from the surface and into the gas phase. This is called evaporation (as opposed to boiling, where the whole liquid is turning to gas at once). You know about evaporation because water does it too (all liquids do at some temp). Water boils at 100C but evaporates at room temp, right? That's because some of the particles get randomly bounced up to 100C-speed and fly off. And the warmer the water gets, the faster it evaporates. Think of water at 80 or 90C. If the average is only just below boiling, that means quite a lot of the particles are over 100C, so a lot should be flying off, right? That's exactly what happens, so much evaporation that you can even see steam rising off the hot water. Visible steam starts at like 60-70C btw, proof that water is producing vapor at room temp, well below its boiling point. So if that's evaporation, what's boiling? Evaporation is when the fastest particles can fly off *from the surface* of the liquid. Boiling requires a hotter temp, with the particles in the liquid flying around so fast and banging about so hard that they knock each other farther and farther apart and begin becoming a gas *all through the liquid at the same time, from within*. That's why boiling forms bubbles of gas inside the liquid and evaporation doesn't. The \"boiling point\" is the temp where all of the material becomes a gas and none can remain liquid. To bring it all home: mercury does all the same familiar things we were just talking about for water. At room temp it is a liquid, well below its boiling point, but some particles are always going fast enough to evaporate, so they do. Mercury being a metal is irrelevant to this property, liquids evaporate. Note that at room temp mercury is farther below its boiling point (356C) than water is (100C), so we can predict mercury will evaporate much slower than water. Only a very small fraction of its particles are going fast enough to fly off. But mercury is quite toxic when inhaled, so that slow evaporation of mercury gas can be a health hazard, especially in a workplace where you could breathe it for years."
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no46sk | How do they get seeds of plants, like carrots to put in little bags, to then plant? | Other | explainlikeimfive | {
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"Carrot seeds are from the flowers. Carrots don't produce seeds until it's second year. The seeds are dried out and kept in a cool dry place. Should get five years of shelf life from seeds. Not clear what you're asking I hope this helps.",
"Somebody plants the plant and lets it grow until it produces seeds at the end of the season, then collects the seeds. For your carrots example, this is what the [above-ground part of a carrot plant]( URL_0 ) looks like. From there [you get the seeds.]( URL_1 )",
"Most veggies make seeds in the following way: first the plant grows and makes flowers (carrots are just the root of the plant), then insects pollinate the flowers. After that, depending on the plant, the flowers either turn into fruit (potatoes make poisonous fruit) which contain the seeds or they expose the seeds directly to be blown into the wind (carrots and parsely do this). Try putting a carrot in water and it will grow a stem with leaves which will eventually flower."
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no4kyr | Hurricanes | How do they form and how do they maintain force? I've always been baffled by this. | Earth Science | explainlikeimfive | {
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"Water evaporates (obviously). How fast it evaporates depends on temperature, humidity, and pressure. Warmer water/air, or lower air pressure, means the water evaporates faster. But here's the rub: When water evaporates and mixes into the air, the air pressure goes down! That means faster evaporation. Usually, this doesn't matter much. Air flows from areas of higher pressure to areas of lower pressure, equalizing things. But when a small area has considerably lower pressure than the air around it on all sides, the surrounding air converges on it, and sometimes something weird happens: It all turns. This is the Coriolis Force: In the Northern Hemisphere, everything tends to turn right. So the air being sucked toward the center all turns, and starts essentially orbiting the low-pressure region, moving around it instead of equalizing the pressure. Water keeps evaporating, the pressure stays low, and the \"orbiting\" air forms a cyclone. Meanwhile, over the ocean, there's no terrain to interrupt the airflow. The evaporation of ocean water and the absence of land strengthen the cyclone. But when it reaches land, or colder waters, it loses strength and eventually peters out."
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no4pjp | In power grids, how fast do individual electrons move? | My understanding is that current flow is like when you have a garden hose that is already full of water: as soon as you open the tap, water instantly comes out of the other end of the hose. So when a generator pushes current through a power grid, do the electrons move at the speed of light (as many believe), or is it more a case of them all bumping each other along instantaneously,, as with the molecules of water in the garden hose? | Physics | explainlikeimfive | {
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"It is a great question. The analogy of water flowing in a pipe, sort of breaks down once you get to the level of electrons and such. 1) Electrons are not massless particles. Therefore electrons cannot travel at the speed of light. The explanation is from Einstein: that anything with mass would need infinite energy to accelerate to the speed of light. 2) What is \"moving\" at the speed of light is the change in the electromagnetic field. The term used is propagate rather than move. 3) The speed of individual electrons cannot actually be measured with precision. But the presence of a voltage in wire will induce a \"general flow\" of electrons in one direction. (Imagine water in a turbulent river - we cannot say what speed any particular drop of water is moving but we can tell how fast the entire flow is moving in general) This flow speed is called \"drift velocity\" and is called drift because in most circumstances it is VERY slow. 4) Drift velocity direction depends on which side of the wire has higher voltage relative to the other. In power grids, the voltage is AC, so it swings from positive to negative. In effect the drift velocity switches each time the voltage switches signs and therefore the average drift velocity in the power grid is ZERO. That is, electrons aren't \"shooting out\" at one end of an electric cable. So one can imagine electrons essentially moving backwards and forwards but not really going anywhere. This is just an illustration - electrons don't organize themselves like balls of stuff and their actual motion isn't like cars going down a road.",
"> Water instantly comes out of the other end of the hose. No, actually it's not \"instantly\", that's the part that happens at the speed of light (for electrons). As far as the electron movement, that's called the [drift velocity]( URL_0 ) of electrons in wire, and it depends on the material (what metal it is, dimensions, etc.), and on the electric field (voltage, etc.).",
"I like to think of it as being more like a tube filled with tennis balls. As has been said, there are a bunch of factors that go together to give you the drift velocity. But this is ELI5, so let's give you a ballpark figure. In an electric circuit, the electrons are moving *slowly*. For example, in an average 2mm wire with a current of about 1A, the electrons are moving at about 23μm/s. That's 23 *micro*meters, or 0.000023m every second. To put that into perspective, it would take about 12 hours to travel 1m at that speed. Or, say there was a wire going straight up, and there was heavy rainfall. The water level could actually rise faster than the electrons in the wire.",
"Two different things here The speed of electricity is not how fast electrons move, but instead how fast the electric field moves. It's the electric field that actually does the work, and that moves at a bit under the speed of light. The electric field at your outlet is constantly changing so there's usable electricity there instantly and you don't have to wait for it to come from the power station The actual electrons don't move much. They bounce around off the atoms in the wire and drift in one direction slowly, very slowly The average speed after all the bouncing around of 1Amp of current in a 3 mm^2 wire(roughly the size in your walls) is about 20 micrometers per second. Each electron is moving a fair bit quicker but with all the bouncing they can't make much forward progress"
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no52k0 | What are the differences between a database, data warehouse, data store, and a data lake? What types of software are used? | Technology | explainlikeimfive | {
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"Let's say you owned a restaurant. A database would probably be used to store the transactions for the month or year. It might have things like the menu items and their prices and all the info you need for the day-to-day stuff. A data store might be a data connection that pulls together some of the database data/views along with an unstructured list of news headlines that have keywords related to your genre of food so you can do some quick analytics that might fall outside the scope of just database data. A data warehouse is basically a long-term version of your database. Instead of just containing a year of data, it contains all your database data since the beginning. You can run heavier queries on warehouses - things that take a long time to run but give you stuff like trends of how popular your chicken entree is until you switched to the new cook a year ago. A data lake has no official structure. It's a pretty new concept and sales teams are desperate to try be the group that determines the om official definition. The general idea is that you can put any and all data into the lake. You don't process any data in the lake - it is little more than a virtual hard drive.",
"Datastore: a digital place where you store data. This can be a database or even something as simple as a file. Database: a datastore with formally defined operations for creating, requesting, updating and deleting data. Databases come in a variety of flavors. Relational database: a database that not only stores data, but also stores the relations of that data. Data is generally stored in tables with rows and columns. The columns of the table generally describe the schema, or shape, of the data. The rows of the table generally represent individual records of the table. Tables can be linked or related to each other with \"foreign keys\". For example, an \"Order\" table might have a \"CustomerId\" column which is a foreign key for the \"Customer\" table, which relates the Order and Customer tables together. This gives you an incredible amount of flexibility in how you can query your data, as you can choose to join the two tables together on the foreign key and filter your data by any column from any of your joined tables. Nonrelational database: a database that avoids storing relational data. These are also known as \"NoSQL\" databases. These databases are generally much faster than relational databases, but come with the downside that querying data is much less flexible. It is still possible to relate data in a nonrelational database but it requires special consideration ahead of time to carefully design how your data will be indexed, partitioned and sorted."
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no6thn | How do fruits lose there fiber content when blended? | Other | explainlikeimfive | {
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"They don't. Whole blended fruit has the same fibre content. But if you squeeze the juice out of a fruit and discard the rest, you're losing the fibre.",
"Juicers work differently than blenders. After you juice a fruit you throw away the pulp/fiber. When you blend it all together you get retain the fiber"
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no78u8 | plutonium, uranium, and how a metal can be used as a power source | Title, how can such a small amount of metal be so powerful/potentially destructive? How is the power extracted? What makes it so dangerous? Any other interesting facts? | Physics | explainlikeimfive | {
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"Gonna try to stick to eli5 as much as possible. The reason why they are so powerful/destructive is because they release alot of energy. Now everything that exists is made up of energy, but in order for it to destroy something that energy needs to be released. There are many types on energy, the one released by Uranium in powerplants is Heat for example. But why does Uranium release so much energy? Its because mass is energy. Mass is what everything physical is made out of, mass is \"stuff\". If something is more massive, it contains more energy. On earth we can refer to mass as weight, so you can say \"1kg of mass\", but that only works on earth. If you take 1kg of Uranium to the moon it will still be the same amount of Uranium, but weigh less since the gravity is weaker. This is important because i will be using weight to explain what happens, just know that mass and weight are not the same. So, what happens with Uranium in a bomb? You split it. You use a start energy, and split the uranium. Why does this release energy? Its because the mass that remains is less. The extra mass has been converted into heat. To illustrate, lets say you have 1kg of Uranium. Now you split all those uranium atoms, as in 1 atom becomes 2 atoms. If you did that with all Uranium atoms, gathered them up and weighed them again after splitting you would expect that to weigh 1kg again right? But it doesnt. It weighs less, our 1kg of mass now weighs less. Lets say it weighs 990grams. What happened to those 10 grams of mass? They became heat. But wait. Heat is a type of energy, and we used energy to split the Uranium. Wont that energy split even more Uranium? It will! That is a chain reaction. In power plants and bombs you use this fact. The energy that splitting Uranium releases is enough to split even more Uranium. If you control this energy you get a powerplant. You release just enough so you can use it for power. If you do not control, and let it just do its thing, you get a nuclear bomb. Kaboom!",
"They're radioactive. Radioactive decay produces heat. This heat can be used to heat up water and produce steam. That steam can then be used to drive turbines. Basically nuclear power is a steam engine that has replaced the coal with nuclear fuel.",
"When you burn coal for energy, you harness the energy stored in the molecular bonds. Nuclear energy harnesses the energy from inside the atoms. The protons and neutrons are held together, nuclear power breaks the atom and releases that power. It is far greater than molecular bonds.",
"The nuclei of atoms hold a lot of energy, in significant part because they are full of charged particles (protons) that repel each other pretty strongly - so the nuclear forces have to be *very* strong to hold atoms together. Since the forces are very strong (compared to the electromagnetic force, which holds the energy of chemical bonds), breaking or forming nuclear bonds can release huge amounts of energy compared to breaking/forming chemical bonds (which is what you would do if you burn fuel for energy). As for how to extract that energy from radioactive/fissile elements like plutonium, there are two main approaches: **Radio-thermal generators**: Radio-thermal generators, or RTGs for short are rather simple: they hold a radioactive material, which produces heat as it decays (since those nuclear bonds are being broken down over time). It's essentially the nuclear analog to a slow-burning fire. RTGs are usually only used for powering things like spacecraft that need a self-contained power source, since the materials you need for good RTGs are often highly radioactive and difficult to produce. **Nuclear fission**: This is what you commonly think of with nuclear power. Essentially, some (but not all) radioactive materials are *fissile*. Being fissile means that on top of decaying by themselves, you can also make them decay in a way that releases energy by hitting them with the right particle (usually a neutron). For materials like plutonium, the fission that happens when you hit them with a neutron makes it release more neutrons, which can then hit other plutonium atoms, fissioning them and releasing more neutrons and so on - this is what is called the chain reaction. Because every atom split can cause more than one other atom to split, this is a process that accelerated exponentially as long as there are enough atoms available to split, which is what makes nuclear power dangerous (and enables nuclear bombs) - you can release a lot of energy *very quickly*. In order to produce safe nuclear power, you need to control the amount of neutrons available to start fission events to keep fission at a steady rate (at which point you are producing continuous heat, which you can use to boil water to run turbines to produce electricity)."
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no7pjj | why don’t rugby/football association players gather around the ball making a circle and advance, protecting it from the other team? | Other | explainlikeimfive | {
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"Rugby league and union have something called a ‘shepherd’. You are penalized if your team has the ball and another team member becomes an obstruction. E.g. you (with ball) can’t run behind your team mate as that stops the opposition from tackling you",
"In football, you would have to commit at least half your team for this tactic, if it went wrong you would be very exposed. Also unlike other sports where this might be feasible (nfl, ice hockey) the guarding players wouldn't be able to throw blocks. Even putting an arm out to try and block someone would result in a freekick",
"There's no such rule as obstruction in football any more, however there is a goal against impeding an opponent. If any team even attempted this, they'd concede a free kick immediately"
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no8a5r | What happens to all the dust we inhale? | Biology | explainlikeimfive | {
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"Most of it gets stuck onto the nasal mucus (boogers) and gets removed when you blow your nose or you spit it out. If you dont, it drips down your esophagus and you eat it, so it gets removed through poop.",
"A good amount of the dust we breathe in makes it into our lungs and sticks to the moist surfaces. Goblet cells in our lungs produce mucus, which traps the dust, and then other cells have cilia, tail-like extensions that move together in waves to move the mucus up and out of the lungs. Then we usually swallow the mucus."
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no8sfl | how do slow release medicines like the contraceptive implant work? | It’s the slow release bit I’m confused by-what stops it all going into your system at once? | Biology | explainlikeimfive | {
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"Going off your example of slow release contraceptives: In the arm implant and the vaginal ring, the plastic that you can see and touch is a copolymer called *ethylene-vinyl acetate*, or EVA. The drug is loaded *inside* the plastic (like it's now a mixed-in component of the plastic; it's drug-plastic) and the drug moves from inside the plastic to inside your body by the process of *diffusion.* Diffusion is a chemistry term for substances naturally moving from areas of higher concentration to areas of lower concentration, like how a fart smell eventually dissipates because the fart particles (farticles, if you will) achieve such a low concentration by moving to the formerly fartless areas throughout the room and away from the high concentration area it started out in (the area right by your butt). Basically, the drug is VERY VERY SLOWLY moving from its area of high concentration (the plastic rod or ring it's been loaded into) to the surrounding area of lower concentration (the inside of your body). It \"wants\" to do this naturally, as a property of how things work on Earth at a molecular level, and so we can take advantage of this and just control its rate. Now we can get to your actual question, which was how it doesn't do this all at once. In the fart room example, there's no barrier between your fart and people's noses, but imagine if there were a special membrane sealed over everyone's noses that was engineered to only let certain amounts of fart particles through at a certain rate. The birth control device has a membrane like that, that only lets a certain amount through at a time. They spend a LOT of effort in the labs determining how to get that right, involving a LOT of chemistry equations and math around the drug concentration and solubility and diffusivity, membrane thickness, permeability, level of actual vinyl-acetate content in the polymer, and more. Tldr: concentration of drug inside plastic is engineered, along with permeability of device membrane, to work with the natural process of diffusion. Adapted from: URL_0"
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no9qg2 | if most of our physical attributes are determined by dominant genes, why are mixed-race people usually an "in-between" color of their parents skin tones? | Biology | explainlikeimfive | {
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"Skin color is controlled by what is known as [polygenic inheritance]( URL_0 ). Traits controlled by polygenic inheritance have an additive effect, rather than the dominant/recessive relationship. Effectively, the more dark-skinned genes that you have, the darker your skin will be. If a black person and a white person have a child, the child will have fewer dark-skinned genes than the black parent, but more than the white parent, resulting in a skin color that is in-between the two parents.",
"Skin color is influenced by multiple genes. If you get some dominant genes from one parent and some other dominant genes from the other you are probably going to be somewhere in-between.",
"Just because genes come in recessive and dominant doesn't mean that each trait is just controlled by one gene. Humans only have something like 30,000 genes. Most traits are through the expression of multiple genes and genes can be used for multiple traits. Edit: Should probably also mention that genes can express themselves differently depending on the environment (the nurture part of nature vs nurture).",
"Dominance is not a simple dichotomy. It can be, as in some genetic diseases: Put simply, if the diseased gene produces harmful things, then the disease is dominant, whereas if the diseased gene just fails to produce something necessary, then one functional copy may be enough, making the disease recessive. Skin color isn't like that. Dominance is incomplete. It also involves more than one gene. Combined, these facts allow for great variation in skin tone.",
"Many traits aren't governed by a single gene but by a substantial number of genes interacting in complex ways; even some traits that were thought to be a single gene have turned out to be multiple genes."
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noag73 | Spinning ring stations, Von Braun wheels, "donut cities" - how would spinning a space station ring generate artificial gravity outwards? | [ URL_0 ]( URL_0 ) visual aid Most renditions of spinning gravity rings imply that the gravity would be applied according to my expertly-drawn left image, like the Stanford Torus. But it seems to me like it would only work if you were sideways, like the right image. Why am I wrong? | Physics | explainlikeimfive | {
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"The picture on the left is correct. The ring station under your feet would be accelerating upwards (towards the center). You will experience this as “gravity”. Since the speed of rotation remains constant after the ring has been spun up, there will be no acceleration along the ring, so the picture on the right is wrong.",
"Ever been on the [gravitron]( URL_0 ) at a fair? It works exactly like that. Acceleration is a change in momentum. If you’re moving forward and the curvature of the wall pushes you upward as the floor rises beneath you, you’ll feel pulled down.",
"You ever try out a marry-go-round on the playground? Like you hop on there and someone starts spinning it super fast. What does your body want to do? It wants to fly off the edge, right? If there was a wall there, as would be in a toroidal space station, you could stand up and walk along that wall (which would be more like a floor at that point) assuming it was spinning fast enough. Easiest way to show you is to have you check out “the gravitron” ride at a carnival. If you ever get a chance to ride one, do it and you’ll understand. See: URL_0",
"Fill a gardening can with water. Start spinning around your own axis. You will find that the water, rather than flying in all directions, is pushed to the bottom of the gardening can. This is what we call \"centrifugal power\"."
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nobik4 | What causes increase in saliva during running? | Biology | explainlikeimfive | {
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"So, the study you linked actually DID find an increase in saliva flow rate with exercise, but that was in CONTRAST to previous studies that had found saliva flow to be *decreased* or *unaltered* by exercise. (The water component of saliva is normally secreted during RECOVERY / non stressful type stimuli, aka your parasympathetic nervous system, while proteins such as amylase in saliva are normally secreted during STRESSFUL type stimuli, aka your sympathetic nervous system.) Since they weren't expecting that, and it wasn't the main objective of their study, they weren't really ready with an explanatory discussion of that result. The best they gave was that the exercise environment was kinda cold (10 degrees Celsius, which is 50 degrees Fahrenheit) which could have stimulated saliva flow, and that they were exercising in that relatively cold room for only 20 minutes and \"under these circumstances dehydration is expected to be limited.\" Usually, the general explanation is that it's not so much an increase in saliva as it is an increase in the THICKNESS (viscosity) of your saliva, which feels uncomfortable in the mouth, and so we are more aware of it and more motivated to spit than usual. The increased viscosity is usually thought to be caused by the dehydration of your oral tissue from evaporation during heavy mouth breathing, but the study you linked above shows an alternative explanation, which is the increased production of MUC5B - a mucus-making protein - during exercise. (They noted that this was counterintuitive, since MUC5B is usually secreted during parasympathetic response, aka recovery and not stress, but again since this was an unexpected result they don't have a super strong explanation for it yet.) The purpose of mucus is to catch unwanted matter in your airway and glom onto it, so that it can more easily be moved along up and out of your airway (ideally cough it out). There is mucus in your lower airway, which is super important for protecting it, but your salivary glands also produce mucins (mucus-making proteins) as well. The study you linked above found that when you exercise, your salivary glands make much more of multiple different proteins, so the protein concentration of your saliva goes up. This is probably due to your glands being stimulated by substances that get released in your body during stress (exercise is definitely stress, to your body). One of those proteins is the mucin MUC5B, one of the guys that determines how viscous (thick) your saliva is. This study found that MUC5B concentration increases with exercise, which is another explanation for the increased viscosity of your spit and therefore the need TO spit. Tldr: it's more that the viscosity increases and makes you feel the need to spit it out. New evidence suggests flow may also increase but not super clear on why yet."
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nobqqv | How do you navigate by the stars if the Earth's rotation means they're always moving? | I just finished my ten thousandth watch if Moana with my son, and I do not understand how you can travel by holding your hand up to the starry sky. It would make sense if the stars were stationary relative to your position, but they're not. A star you measure at 10pm is in a completely different position by 2am. I understand the Disney version is an oversimplification, but how does the real thing work? | Physics | explainlikeimfive | {
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"> A star you measure at 10pm is in a completely different position by 2am. Except for one. Since the stars *turn* in a circle there's one spot in the sky that doesn't move— the center of the circle. In the northern hemisphere, just by coincidence, there's a star almost exactly at that spot. A fairly bright one, too, called Polaris, at the end of the handle of the Little Dipper (the tail of Ursa Minor). If you can see and identify Polaris you know that that direction is north, which lets you keep the boat pointing in the right direction. But also, if you can measure how far it is above the horizon, *you're that far north from the equator,* in terms of degrees latitude. If you're in the southern hemisphere, it's harder. There's still a stationary spot in the night sky, but there's no star right on top of it. You can do the same trick by finding the spot where an imaginary star *would* be (by recognizing the stars nearby), but it's harder to get good measurements.",
"The Disney version wasn’t that simplified. Polynesians really did just use the hands. The stars move in a very specific way in tandem with each other. If X shifts to the west, Y will come from the East. These are setting points, so like when the sun sets, you know which way is west and the general time. As you developed experience, you memorized sets of stars and could navigate that way.",
"Stars follow predictable patterns. A star moves across the sky over the course of a day, but if you know where it was at 2 AM last night, you know it's going to be in pretty much the same spot at 2 AM this night. Obviously stars move over the course of a season as well, but there are stars that are visible all year, called circumpolar stars, so those stars in particular are useful for navigation",
"Some very good explanations on how using a fixed point can give you latitude. In order to accurately get longitude, you'll need an accurate time keeper (i.e. a watch). That's actually what drove the race toward making an accurate clock."
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nocjq1 | why is it that adblockers kinda "expire"? | basically I got tired of adds as you do and got a ad blocker it work fine for like \~4 months then i started seeing ads again. later I downloaded brave browser turned on shields and no ads for around \~ 4 months then I started seeing ads again. so I came to the conclusion that google somehow detected that I was using a ad blocker and somehow bypassed it if this is true then how dose it work or if I have it wrong then why? | Technology | explainlikeimfive | {
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"It's a game of cat and mouse often. Ad companies find ways around ad blockers, so sometimes you will see some ads on certain websites for some time until ad blockers start catching up again. Also, you need to update your ad blocker regularly.",
"Ublock origin is currently the best adblocker around. I haven't seen an ad since I started using it. But you do have to let it update. Some adblockers will take money from groups like Google to whitelist their ads so it won't block them anymore. Ublock origin does not, ublock does.",
"1. Adblockers work off a blocklist of known ad-tech domains. They block all requests to those domains preventing ads from loading. It's trivially easy to keep this list updated, so most ad tech companies don't bother changing their domains to get around this because of all sorts of other issues it would cause them. You are seeing ads served from the publishers domain that you are on. Those cant be blocked as easily since they come from the publisher alongside the content that you want to see. 2. Brave is an ad tech company that offers lots of ad formats to buyers while blocking other sources of ads. You are seeing ads from the publisher served like i mentioned above but you are likely also served ads by Brave",
"uBlock Origin doesn't 'expire', but you need to let it update. I don't see ads anywhere, and haven't for a long time.",
"Thats an assumption. But what ad blockers essentially does is scanning the webpages you visit for potential ad content before it's rendered in you browser and hides it. So if the way ads are displayed is changed the ad blocker has to make changes too. I'm pretty sure big browsers make changes actively to make it harder for ad blockers as well as they make money from ads (think google)"
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nodw5y | mRNA levels. This has nothing to do with SARS-CoV-2 vax | Reading over something from lecture today there is a ppt slide that states "Evaluation of levels of mRNA and the signaling occurring at this level is what we refer to as gene "expression" I'm a physical therapist, now in nursing school (for eventually psych APRN), and have taught college-level A & P for the past 3 years. I'm not a complete genetics n00b, but I do not understand what a "mRNA level" is. I'd appreciate any input. Thank you! | Biology | explainlikeimfive | {
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"DNA encodes our genes. The mRNA is a copy of a specific gene that is made to carry the information to the protein manufacturing places (ribosomes). If you want a lot of a particular protein made, you make lots of the mRNA. Example. Skin cells make lots of collagen mRNA because they want lots of collagen made. So, the collagen mRNA levels are high in skin cells. They don’t make any hemoglobin. So the hemoglobin mRNA levels are low in skin cells.",
"The nucleus making mRNA is basically it placing an order for a protein. So think of the mRNA like order tickets at a restaurant, you can tell what is being ordered the most by the number of tickets placed for each menu item. Further, you can make inferences from looking at the tickets. E.g. if most of the tickets are breakfast items, then it was probably breakfast time when they were placed."
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nodz8m | Why do some of us sneeze when going from darkness to sunlight? | Biology | explainlikeimfive | {
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"A.C.H.O.O. Syndrome (yes,seriously) aka “photic sneeze reflex” isn’t fully understood but is thought to likely be caused by the fact that eye and nose nerves run into the brain in the same place so a very strong signal from the eyes might get misconstrued as a signal from the nose needing a sneeze to clear it.",
"I do this too. I read years ago only 25% of people do this. It doesn't happen all the time for me but if I ever feel a sneeze coming on that isn't \"fully rendered\" I can glance up at a light or the Sun to force it to finish. Pretty useful for me haha. Having a half way sneeze is a very annoying feeling.",
"[veratasium had a video explaining this]( URL_0 ) I thought everyone did it until my wife was worried that our infant son had some allergies because he'd sneeze everytime we went outside. Turns out we're in a minority"
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noe3kj | How do silent letters end up in words? | Other | explainlikeimfive | {
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"You got it actually. In many cases where the spelling doesn't match the pronunciation, it's because the pronunciation has changed over time but the spelling didn't.",
"English adopts words from many other languages. So there isn’t likely a solid explanation to cover every case. Some silent letters are from digraph pairs. Two letters combined together would make a new sound which the language of origin for a word has and our doesn’t. Over time, the pronunciation of the word changes to fit our dialect and normal sounds, and the digraph no longer makes any sense because we just don’t make that odd sound anymore. Receipt is part of a small set of words where the extra letter was added because of the origin of the word prior to the language we adopted it from. We took that one from French, but added the p because it was part of the Latin word that the French word came from. Why was that done? No clue at all. There are a few other words where this happens, like island. But many of the words with silent letters have better explanations."
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noem64 | Why does cold water make my sore throat worse, and why does warm water sooth it? | Generally, shouldn't colder temperature help with inflamation. On that note too, why does gout, another inflamation, also react badly to the cold? | Biology | explainlikeimfive | {
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"The esophagus (food pipe of the throat) is one long muscle. While the heat will open the vessels, it will also help relax the muscles. Inflammation is also part of our healing process, so increasing blood flow can help some. So cold, while it can numb pain, doesn't help healing in those regards"
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nofllr | How do you jump from zero to one if there are unlimited real numbers in between them? | Mathematics | explainlikeimfive | {
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"It doesn’t matter how many numbers you can fit between zero and one, what matters is the difference between the start and end points. The difference between zero and one is not infinite, it’s one. One is a finite number, and so takes a finite time to cross. Sure, you cross an infinite number of real numbers while doing so. But the distance between each of those numbers is *infinitesimally tiny,* such that the *total* distance between them all is (not coincidentally) exactly one.",
"Can you explain what \"jump\" means? Is it something in the likes of \"isn't 0-1 same as 0-infinity but just on a smaller scale?\" To begin, the first number system was composed of \"counting numbers (1,2,3,4...), (I,II,III,IV...)\". In here, it is defined as 2 is the next jump from 1. It was defined. It's value was set. The \"values\" were purely theoretical but it is considered to be true according to this system. Later on, this system expanded with the addition of zero (whole number system), negative numbers (integral system), fractions and decimals (rational number system) and so on. The difference between 1 and infinity is that 1 has a set value while infinity does not.",
"By skipping over them as if they did not exist. Counting is not a continous action, it is irrelevant what is between the elements you are counting because you do not need to touch on them for a fraction.",
"There are unlimited real numbers between all real numbers, but that doesn't really matter when it comes to counting or moving between numbers. 0 and 1 are both integers, so if you are counting in integer steps then you jump all of those infinite non integers between them. If you are trying to count in real numbers however then you do have a problem, this is why the set of real numbers is described as uncountable."
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nofqdt | How does reverse image lookup work? | Technology | explainlikeimfive | {
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"There's not a single way but the general idea is to first downscale the image to something small (like 32x32) and then use an algorithm that detects disctintive features of that image and encodes them into an even smaller value, it's like some sort of extreme compression. Comparing this encoded values is much quicker since they're much smaller than the original image. Also the search engine is continually looking for images in the web in order to keep a database of encoded images and the corresponding addresses. So when you give it an image for a reverse lookup the engine encodes the image in the same way, then looks for similar values in the database and finally obtains the images from the stored addresses.",
"There's a paper on the subject: [Fast Multiresolution Image Querying]( URL_0 ), by Charles E. Jacobs, Adam Finkelstein & David H. Salesin in the 1995 Siggraph proceedings. I implemented this from the paper to manage and sort my own image collection, and later worked on it at Google as my 20% project. I don't think any of my own work actually went into Google's reverse image search, so I can't say if this is actually how they do it. The gist of it is this: you scale the image down to a reasonable size, and then use a Haar Wavelet transform on it. This is similar to a Fourier transform, but easier to compute. The transform returns an array of values that basically represent the components of the image in the spatial frequency domain. You pick out the 40 most significant values, truncate them to save space, and essentially construct a \"signature\" of the image. The rest of the algorithm is just a fast way to match the signature to the signatures of images in your database.",
"When you type something into Google, Google doesn't really care that it was words that you typed in. It converts that into digital information, and then uses that information to search for similar information, and then it is translated back into words. With reverse image lookup, it takes that image and converts it in two digital information. Then it searches all over for the same or similar digital information, before converting that information into images again."
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nofyi2 | Does Gerd destroy the lungs? | Biology | explainlikeimfive | {
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"I am a doctor and one of my specialties happens to be the lungs :) so hopefully I can help! GERD (gastroesophageal reflux disease, aka chronic acid reflux, heartburn) doesn't \"destroy\" the lungs in the dramatic sense, but can cause serious damage ***over time*** if the acid reflux is severe enough that it repeatedly comes up the esophagus and spills back into the trachea and then down into the lungs themselves. I have seen a variety of damage from this which can range from: very *mild* (evidence of inflammation only seen on imaging such as CT scan) to *mild* (pesky chronic cough), to *moderate and severe* (frequent coughing, difficulty breathing, and significant abnormalities on imaging). I have even seen *very severe* where major structures of the lungs are severely damaged or scarred, and someone needs extra oxygen to breathe comfortably. It generally takes a long time of severe, untreated GERD for it to start seriously impacting your lungs -- and the first sign of a problem *usually* begins with more frequent need to \"clear your throat\", voice changes (hoarseness), and intermittent dry coughing because the acid irritates your vocal cords and upper windpipe (trachea) first, before it eventually affects the lungs themselves. However, some people do not even realize this is happening unfortunately, or do not feel symptoms of reflux, and thus it goes untreated. Depending on the extent of damage, it can sometimes be reversed if the reflux to the lungs stops (inflammation can be reversed but scarring and structural damage usually does not reverse). Anatomically, acid reflux should not be able to affect the heart at all because there is no connection from stomach acid that can reach the heart. GERD is relatively easy to treat with medication that your doctor can prescribe or that you buy over the counter at a local pharmacy. It is always important to get checked out if you have GERD symptoms consistently for longer than a few weeks/1 month time because it *may* be a sign of a more serious issue that needs to be addressed. Hope this helps!"
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nogioa | waking up to a sleeping arm | Today I woke up to the most dead arm I've ever had. I even sat up and placed my hands on knees and realised my left arm was dead, I couldn't even move it. I was telling my brain to move it but nothing, I picked it up with my right hand and couldn't feel a thing but then I felt a "blood rush" to it and slowly I could move my fingers but very badly. After few mins I was good, what happened? | Biology | explainlikeimfive | {
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"It's not caused by lack of blood flow at all. It's caused by nerve compression. Compressing the nerve cuts off communication to the limb, which is why you can neither feel it nor control it. Cutting off blood flow can cause ischemia, or damage to the tissues of the arm, like the muscle, but nerves have their own blood supply. Cutting off arterial blood flow to a limb is very difficult and major arterial blood has nothing to do with the ability of your extremities to communicate with your brain. The pins and needles sensation you get after removing the compression from the nerve is called parasthesia and is caused by the nerve randomly firing. This is due to ionic flow in the nerve being restored. It takes a minute for communication to return to normal. You will usually wake up if you have a compressed nerve before permanent damage is done, but if you were knocked unconscious or passed out due to drugs or alcohol and had a compressed nerve for hours it can cause permanent damage that takes days or months to repair as the nerve regenerates."
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noglgq | What is soil and how do plants feed off of it? | Biology | explainlikeimfive | {
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"Soil is a fascinating complex material. Most of it is from the decayed matter of other things - compost, essentially. When leaves fall from the trees, they become part of the soil (etc.). With this there are also clays of various kinds (powdered rock essentially), sands (crumbled rock essentially), and other minerals and organics, the products of worm and fungus and bacteria metabolism, and so forth. Soil is a wonderful thing and we lose way too much of it through erosion and deforestation (which leads to more erosion). Plants \"feed\" from it for various minerals that they need, like some need to get nitrogen from the soil, while others can get nitrogen from the air. They do this via their roots, absorbing water and the dissolved minerals up into their systems. As for the bulk mass of the plants, as in most of what makes a tree a tree, they get that from the air. Plants take the carbon dioxide from the air and release oxygen as a waste product. The carbon from the carbon dioxide becomes the carbon in their cell walls. Cellulose, for example (like the wood of your door / table / apartment / etc) is (C6 H10 O5)n. Those six carbon atoms in the molecule come from the carbon dioxide the plant \"breathes\". Related, this is why trees help us mitigate climate change, because they literally suck the carbon dioxide out of the air. And this is why burning fossil fuels make climate change worse, because they put that carbon dioxide (etc.) back into the atmosphere."
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nohg3c | Why is it sometimes not recommended to induce vommiting if you accidently swallow a dangerous substance? | For example some lighter fluids | Biology | explainlikeimfive | {
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"Doctor here, and the other posters are correct in saying that the act of inducing vomiting can be more dangerous than the ingestion of the substance itself. Besides burning the lining of the esophagus, there is also a risk of esophageal tearing from excessive vomiting and subsequent bleeding from the tear (made worse from the already irritated tissue). Many substances can be detoxified in a safer manner, with timely medical attention. It is better to contact your local emergency authorities (e.g. poison control / 911 in the United States) rather than guess yourself, as they can guide you specifically what to do in the event of exposure to toxic substances.",
"Everyone's mentioning the risk of damaging substances transiting the esophagus twice, which is true. But the other reason they give this instruction is the risk of aspiration into the lungs. All of these instructions assume access to modern medical assistance, BTW. You'll also see \"don't give activated charcoal,\" for example, but not (always) because it doesn't work. More like the experts know that \"get your ass to a damn hospital\" is like 100x better than \"just eat a bunch of activated charcoal and expect that to be sufficient.\" They don't want people thinking they should go for plan B when plan A is within reach. Another one is: if your kid drank the old antifreeze (the formulation that tasted sweet), they'd say \"don't give the kid vodka.\" Because they really mean \"don't try to fix this at home - take him to the hospital!\" But if there's a natural disaster that's blocked your access, hospital too far away, you're in a country without medical support, zombies surround you, etc, then alcohol is, actually, the right treatment.",
"Let's say you drank something corrosive like drain cleaner. It would severely damage - corrode - all the tissues on the way down. It you vomited it up, it would do the same thing to the already damaged tissue & make your situation worse. The main component of stomach acid is hydrochloric acid, which is powerful stuff! So, our Stomach lining is designed to handle strong acids. It's better to keep that drain cleaner in the stomach. The docs will suck it out orhave you drink stuff that absorbs the acid & reduces its damage the rest of the way down. It's usually some nasty charcoal stuff.",
"Hospital pharmacist here, in addition to the better alternatives such as neutralizer agents/suctioning, one of the primary purge inducers - syrup of ipecac was discontinued in 2010, in large part due to multiple studies that determined that purging was highly variable and risked more harm than good (esophageal damage, aspiration into lungs, etc. as mentioned by other posters).",
"Some things will cause more damage to the esophagus coming back up. You either have pump it out or take something to counteract it first",
"Some fluid will burn your throat on the way up. That will cause greater problems run. And with a raw throat, stomach acid, and whatever else the fluid has to leach into you. That’s pretty bad mix"
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nohp03 | It seems like the singers I watch all have a "valley" down the center of their tongue. Does this help them sound better? | Biology | explainlikeimfive | {
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"Not necessarily, what really helps the singers sound good is practicing breath control and learning how to make the sound resonate within their throats and mouths. Its basically all practice and repetition the more they use those muscles the better and stronger they get."
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noigwo | If blue portion of the white light spectrum is absorbed (scattered) in the atmosphere due to Reileigh scattering, does it mean that what we perceive as, say, purple colour would look different without the atmosphere ? (because more of the blue spectrum would be shining on the object) | Physics | explainlikeimfive | {
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"No. Scattered isn't the same as absorbed. The blue is scattered so it seems to come from everywhere, the rest directly from the Sun. The *net* is the full spectrum. You get the blue and red and yellow. In the sky we see separate, but the total is white."
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noka9x | If it takes two molecules of hydrogen for one of oxygen to form water, why is there more oxygen than hydrogen in our oceans? | Chemistry | explainlikeimfive | {
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"There is more oxygen by mass because oxygen is significantly more dense (more mass per oxygen atom) than hydrogen. By number of particles (atoms) there is more hydrogen.",
"There isn't, if you count number of atoms. But such measurements are usually done by *weight*, and each oxygen atom weighs, on average, about 16x more than each hydrogen atom. So even though there are two hydrogen atoms per oxygen atom, there's still 8x more oxygen by weight.",
"It takes a lot of energy for a water molecule to separate into its components, so the oxygen and hydrogen dissolved in bodies of waters won't be from there. Oxygen is produced by photosynthesizing organisms floating in the water, and to an extent it's released from hydrothermal vents. Hydrogen isn't produced at the scale of oxygen within oceans."
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nokv85 | Why does an aircraft tire decrease in pressure when weight of the aircraft is applied? | Was installing an aircraft tire the other day and checked the psi on it prior to the install and it was a bit high, was going to bleed off some of the pressure until my coworker informed me the psi will drop a bit once installed on the aircraft. In my mind I expected if you add the weight of the aircraft pressing down on the tire that it will increase the pressure inside of the tire but sure enough I checked it afterwards and it was back within limits. What am i missing here? The tires are filled with nitrogen but wouldnt that be irrelevant as it's still occupying the same volume? | Physics | explainlikeimfive | {
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"Increasing the weight of the aircraft deforms the tire. Makes the cross section of the tire more circular, which increases the volume of the tire. Increased volume means lower psi. However, I wouldn't think this deformation would be enough to change the psi that much. However, you should always check tire pressure fully loaded.",
"Interesting. No idea but I'd be curious if you were to remove it from the aircraft and remeasure, would it still be high, or now low."
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nolura | Why do we make the scrunched up “sour” face when we eat something sour? | Biology | explainlikeimfive | {
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"It's an evolutionary response to protect your teeth. Sour tastes means acid which is bad for your teeth and scrunching your face pulls liquids in your mouth towards the center away from your teeth."
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nom7nj | Why do men pee in these crazy urine streams after having sex? | Biology | explainlikeimfive | {
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"Just a quick reminder that males have a spongy urethra and this particular structure creates a spiral urine stream which expels urine at higher speeds and this functions as a way to remove obstruction, like sperm in this case. Females do not have this structure and why there's a higher incidences of UTI's for females vs. males. After sex, you have a combination of foreign objects there such as: * sperm * lubrication * vaginal fluids * spermicide Which clogs up the very tip and, in the case of sperm, parts of the shaft. This is why it's always good for men (and women) to pee (and wash off) after sex because it cleans, well, everything. The same streams can happen at any time throughout the day but for similar reasons: basic blockage in the tunnel, so to speak.",
"The most likely culprit is drop of semen. It can dry and glue parts of the opening distorting the flow. The guys starts peeing expecting it to flow straight like always, and instead shoots off in a weird direction.",
"The crazy urine streams are caused by semen that has dried at the exit of the urethra. After a short while, the urine dissolves or dislodges the plug and the stream returns to normal",
"Aside from the obstructions mentioned by others, also attempting to pee with erection or after a prolonged erection can cause this just because the head is engorged with blood, thus changing the overall shape of the opening. A bit like lightly squeezing the end of a straw while trying to spray water through it. The water isn't prevented from coming out, but it definitely comes out in a significantly different spread!",
"Pro-tip for your pro tip: break the blockage before urinating by spreading open the opening of the urethra.",
"I've got a tattoo here that fully illustrates.... It's of this rebellious young man, and he's urinating on an FM radio. And then this other stream of urine is going onto that television set. Implausible, I know, but I like to think that he had sex the night before, and a little bit of residue is blocking his urethra, allowing the urine to flow in two separate directions"
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noo64u | When migrating south do birds take breaks? | How can they fly non-stop for thousands of miles? Do they stop and take breaks? | Other | explainlikeimfive | {
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"I may be wrong but I believe this was answered recently. I believe some birds are able to turn off half their brain at a time, in order to rest the other half. Or they can sleep for a few moments and wake for a few moments, rinse and repeat. Their structures also allow them to stay up without using absurd amounts of energy. Their bones are hollow, and the way some birds increase their oxygen intake allows them to be much much lighter than humans. (I don't know enough to go super detailed so hopefully someone else can)",
"\"Yet the most incredible feat of deliberate sleep deprivation belongs to that of birds during transoceanic migration. During this climate-driven race across thousands of miles, entire flocks will fly for many more hours than is normal. As a result, they lose much of the stationary opportunity for plentiful sleep. But even here, the brain has found an ingenious way to obtain sleep. In-flight, migrating birds will grab remarkably brief periods of sleep lasting only seconds in duration. These ultra-power naps are just sufficient to avert the ruinous brain and body deficits that would otherwise ensue from prolonged total sleep deprivation.\" Source: Why We Sleep, by Matthew Walker, PhD. Pg 66. Dolphins and whales do have the ability to have 1 half of the brain get Non-REM sleep while the other half is totally awake, and switch once the one half gets enough sleep. And birds can do this as well! \"Things get even more interesting when birds group together...The flock will first line up in a row. With the exception of the birds at each end of the line, the rest of the group will allow both halves of the brain to indulge in sleep. Those at the far left and right ends of the row aren't so lucky. They will enter deep sleep with just one half of the brain (opposing in each), leaving the corresponding left and right eye of each bird wide open. In doing so, they provide full panoramic threat detection for the entire group, maximizing the total number of brain halves that can sleep within the flock. At some point, the two end-guards will stand up, rotate 180 degrees, and sit back down, allowing the other side of their respective brains to enter deep sleep.\" Same book, pg 64."
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nooax3 | how the fuck do cameras work? | Technology | explainlikeimfive | {
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"A camera has a very light sensitive sensor ( or in an analog case, film) thatight is allowed in very quickly. The brighter the light outside, the faster the shutter opens and then closes. If it is a digital camera, the light is recorded and then written out to a digital file on a memory card. If it is an analog or film camera, the light exposes the film . The film is then placed into a chemical bath to make a negative that can be used to make a print.",
"A tiny pinhole allows light in. This light reacts with something, in the case of digital cameras it is a image sensor chip. This chip is divided up into thousands of squares, which are the pixels. The pixels assign a value to the light it is in contact with This data can then be reconstructed into an image on a computer Cameras before digital cameras worked by exposing a substance to light. that \"burns\" the image into the substance, creating a picture. Edit: wording",
"Willard Boyle, who was working at Bell Labs in 1969, invented a device called a 'charge coupled device'. When the CCD is exposed to light the layer of circuits being exposed can record the photons hitting it as an electric charge. After this happens, a control circuit instructs the circuits that were exposed to light to hand their charges to a coupled capacitor (hence 'coupled') and the last capacitor in each array plops the charge into a current integrator. After this happens the voltages can be recorded in memory as a series of bits - the languages computers understand. If you know the size of the image sensor, the number of capacitors hit by the light, and you can record the voltages at each capacitor hit by the light, you can create a black and white image. If you want a color image, you put a bayer filter in front of the CCD and now each pixel will only pick up a specific wavelength that corresponds to blue, green, or red. If you have enough pixels you can create a color image using a process called 'demosaicing', which is complicated - but think of it as the computer taking all of the data from the pixels and combining the colors to make a continuous color image."
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noogyk | can you lose contact lenses to the sides of your eyeballs or eyelids and what protects it from happening? | It's been a question that has been bugging me for a while | Biology | explainlikeimfive | {
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"Yes it can slide to the side or under the eye lid. It stinks when it happens and can sting. Mostly to fix it you lift the eye lid off the eye a little bit and move the eye around till it moves back to a place you can reach it.",
"Generally speaking, two things keep them in place. Your eye is not perfectly spherical. The cornea, where the contact sits, protrudes a bit. The contact is curved like a suction cup that is perfectly shaped to fit the curvature of your cornea. So the contact stays in place because that’s where it fits best. Also, pressure. If you were to wet your fingers with contact solution, then squeeze a contact between your fingers, the contact will slip out. The white surface of your eye (called the sclera) and the skin on the inside of your eyelids (called the conjunctiva) are much more slippery, and these tissues push up against each other in order to hold your eye in place. This pressure tends to squeeze things out if they are inserted not this space.",
"it happened to me a couple of times, the lense moved deep to the side of the eyeball and kept stuck there for a while, with the irritation and the itch that comes with that. For what i know, the lense can’t be there forever since basically it has nowhere to go but out the eye, your body should reject it if you can’t reach it, but i don’t know really what could happen. In my experience, it took time but eventually the lense move back to the “front” of the eye and then you just grab it.",
"Happens to me all the time. The trick to getting it back to the front is to close your eyes and look in one direction as far as you can (like look as far to the left as you can), keep your eyes at that extreme angle and then look all the way around 360 degrees (you're rolling your eyes but at the most extreme angle you can). This motion usually brings the contact back around. The crummy part is when this happens when you don't have access to saline or a place to wash your hands. You're better off just closing the eye until you can at least wash your hands before you attempt to remove or replace the errant contact."
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nopj9q | (): so grapes and raisins are the same thing, but grapes cost so much more than raisins. Why is this? | I mean, raisins are grapes that have been processed many times, being dried out and having God knows what else done to them. So with all this extra processing, shouldn't they cost more than plain grapes? | Economics | explainlikeimfive | {
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"It's harder to transport fresh grapes and have them arrive in the store looking sweet and juicy than it is to dry the grapes and bring boxes of raisins to the store. You can put raisins in a very cold or very hot truck and not lose much quality, but get fresh grapes too hot or cold and they are ruined.",
"Raisins are made from a wide variety of grapes so they can be made with cheaper easier to grow, lower quality grapes than the fresh grapes we eat. A lot of places also sun dry raisins, which adds 0 cost to the process. Generally other than that just a bit of sulfur dioxide is the only additional cost to keep them from turning brown. Fresh grapes also go bad faster so they need to be shipped faster whereas raisins are shelf stable for a lot longer. So there are added costs along the way to getting grapes to market in a timely manner.",
"Raisins can be made with lower quality grapes that people may not want to eat fresh. They can also be shipped by cheaper means (over longer period of time, in ambient temp, etc). Grapes meant to be consumed need to be higher quality and generally need more expensive shipping means so they can get from farm to supermarket before they rot."
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nopklw | How do Antidepressants work? | Biology | explainlikeimfive | {
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"Basically there are a few \"feel good\" neurotransmitters. When there isn't enough of them released, you can get depression. As another comment explained, there are basically two ways to fix \"not enough feel goods\" in the brain. 1.) Keep the \"feel goods\" in the synapse (space between neurons) by blocking their uptake on the receiving end (SSRI). This works if your problem is caused by not enough serotonin specifically. Or 2.) Stop the enzyme that breaks down the feel goods (MAOIs). This works for lots of things so is a better option for those that an SSRI doesn't help. The tricky bit is you can't just tell which \"feel good\" isn't in the right amount in the brain. You gotta kinda throw things at it until someone feels better.",
"Your brain makes a chemical, serotonin, that makes you feel good. Sometimes the receptors, or sockets, that receive serotonin and transmits the good feeling through your brain don’t get enough. There are two kinds of antidepressants but both seek the same result: more serotonin floating free for the receptors to get more. SRRI blocks the re-uptake sockets that absorb surplus serotonin to recycle it. Instead, it remains floating around so more receptors can receive it. MAOI prevent the release of a enzyme that breaks down the serotonin (again, recycling it), so that like the SSRI, more of the stuff’s left floating for the receptors to pick up and transmit a good feeling.",
"There are a whole ton of medications and kinds of antidepressants if you include off-label use, but the general types are SSRIs (selective serotonin reuptake inhibitors) and MAOIs (monoamine oxidase inhibitors). Their actions can be complicated, probably too complex for an ELI5, but they change the way that neurochemicals operate in the brain. SSRIs help to increase and then maintain serotonin levels in the brain. MAOIs lower the production of monoamine oxidase, which operates to lower serotonin, dopamine and norepinephrine in the brain. By lowering the monoamine oxidase, you increase the levels of the neurochemicals it acts on just because there's less of the monoamine oxidase to reduce them.",
"Just a word of caution about all the ELI5 explanations: they're assumptions about what we think *maybe* occurs, not what we know occurs. The only truly ELI-5 explanation is that there are some simple ideas we are investigating, but we just don't know because it's all very complicated. E.g. 1: people say it increases the availability of seratonin and this leads to more receptor response. But that's on the short-term: your body actually responds to the excess seratonin availability by decreasing seratonin production. Your brain goes through a cycle of over-abundance, decline of seratonin in response, and a small rebound back to production. Overal, the effect seems to be DECREASED activity for people who use the medicine long-term. E.g. 2, it's a major oversimplification to say seratonin or dopamine make you feel good. There are different *kinds* of seratonin receptors in the brain, and different seratonergic pathways that do many things, not just make you feel good or bad. Similar with dopamine. Dopamine is also deeply related to Parkinsons disease which makes you shake, but we don't say dopamine is a \"anti-trembling chemical.\" E.g. 3, the \"selective\" reuptake inhibitors are just preferential: they also act on other neurotransmitters and have secondary affects on the production of unrelated neurotransmitters (for reasons we do not understand), and it's totally possible that these \"secondary\" effects are actually crucial. These complications (imo) likely explain why one medication doesn't work for everyone: the number of specific pathways, the density of specific receptor types, and secondary effects all combine in a very complex way, and so we have a lot of different medications that only work for some people. Since we don't understand why, the best we can do is go through each medicine one-by-one until they find one that works for you, or you determine none of them work (which unfortunately happens for about 33% of depressed patients or more; it's called treatment resistant depression, which also includes psychotherapies and other treatments like transcranial magnetic stimulation not working)."
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noq0st | Why do we often associate “higher” sounding vowels (E, A, I) with sharp edges and “lower” sounding vowels (O, U) with round/dull/circular edges? | A wiki on the topic URL_0 | Other | explainlikeimfive | {
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"It may have something to do with the literal way that we make those sounds with our mouths, make an o or u sound and you will find your mouth contorting to that shape, we see other people make the o sound and so that's the association that cements in our minds, since it's the same mouth shape for that sound globally, it becomes a universal concept that o is round.",
"To quote the researchers in the source of the link you included: \"The Kiki-Bouba effect corresponds to a sound-vision synaesthesia, probably between the tone of vowels and the vertical or horizontal aspect of figures.\" Essentially, in some humans, perceiving something with one sense will cause them to perceive something with another (e.g. some people who hear certain musical notes will perceive colours corresponding to those notes). It seems as though we are hardwired to make connections between different types of stimuli. In that experiment, it showed we associate rounder objects with longer, 'softer' noises (b, p, o, etc.) and sharper objects with noises that are more short and 'hard' (k, t, e, etc.)."
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nos94e | How are you able to feel wetness through latex gloves without getting wet? | Other | explainlikeimfive | {
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"You can feel the lubrication that moisture provides between the glove and the other surface. You can feel evaporative cooling as the moisture evaporates. You can feel the heat transfer from your skin through the gloves yo the (presumably) cold liquid prior to evaporation. All three are the same phenomena that you would feel if there were liquid directly on your skin, so it feels very similar: enough to potentially trick your brain into thinking your hand is wet.",
"You're not \"feeling wetness\". You are feeling pressure and temperature changes that your brain has been trained to perceive as wetness.",
"Your brain perceives localized changes in temperature and pressure as the feeling of \"wetness\". For example: your eyes see your hand go under water but your brain feels temp and pressure changes - so your brain adapts to tell you this is what wet feels like. Since you can feel temperature and pressure changes through latex gloves your wired to \"feel\" wet, even if you aren't actually wet."
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nosnbk | Why ice helps with bruises, burns, torn ligaments, and injuries in general? | Biology | explainlikeimfive | {
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"Ice helps the blood vessels constrict, helpful in the case of inflammation. It can also numb the area for the pain.",
"Ice temporarily decreases blood flow to the affected area and reduces inflammation (helps bruises). Reduced circulation essentially numbs the pain (helps other injuries). You can't feel your foot \"falling asleep\" because of restricted blood flow (icing an injury), but you feel the *rush* of circulation when blood flow returns (removing ice). Your brain perceives the first feeling as tingling or pins and needles because you aren't injured - on the flip side when removing ice from injuries the pain replaces tingling *because* of the injury."
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notzkq | if the heart is a muscle, how can we take muscle relaxers without interfering with our heartbeat? | Biology | explainlikeimfive | {
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"We can't actually, but its the degree of interference that's the trick. If you take a muscle relaxer, something like flexeril, and you take it at the prescribed does, you should be fine. Your heart will relax, and you can have side effects because of that, like dizziness, fatigue, etc. But it isn't going to stop and you won't die. If you take a whole bunch of flexeril, then you will die.",
"The heart is cardiac muscle. It is very similar to but has some distinct mechanisms from skeletal and smooth muscle. Certain drugs can more selectively target skeletal or smooth muscle and only have minor effects on the heart by exploiting these differences"
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nousih | How did Hollywood become the center for pop-culture and the film industry both globally and in just the USA? | Other | explainlikeimfive | {
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"Mostly just a coincidence. Back when movie cameras were new, they were under patent and had to be licensed, and that was expensive, and it was easier to dodge that if you went out west. And once you have film studios in a place, well then you have actors going there for work, and stagehands going to build sets, and seamstresses making costumes, it snowballed into a lot of film industry stuff being built around LA. It could have been anywhere, could have been Salt Lake or Seattle just as easily. Nowadays the industry is physically spreading out, what with it being a lot easier to move people and stuff around. A lot of physical filming these days is done in Georgia and Texas because they offer tax breaks for movie and TV production. As to why it became a global center of film too, the really simple answer is: America was left economically strong after WWII right when the movie industry was picking up, Europe had been bombed to hell and what industry they had was still rebuilding, and America was exporting *everything* back then, which included a lot of cultural exports like film and music and literature.",
"The simple reason, it had warm and predictably sunny weather and diverse terrain perfect for movie backdrops. Additional theory is that Thomas Edison had patents on motion picture capture, but in California filmmakers couldn't be sued for infringing on those patents by making movies. Perfect storm of circumstances essentially.",
"A couple of studios set up shop there because the land was cheap. Actors showed up to work and other studios popped up because that’s where the talent was. Which encouraged more actors to go there ...",
"WWII devastated industry and economies all over Europe and they were in no position to compete with a US film industry that didn't even slow down during the war. Since the US was the ascendent cultural and economic power and occupying half of Europe it could distribute its culture more easily. Europe did bounce back with its own film culture in the 50s and 60s but these were small scale, art house films and couldn't compete with the big spectacle Hollywood films, especially in the US. edit: In the silent film era, there was more international viewership of cinema, but when talkies started, that went in steep decline, especially in the US."
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now728 | How did we determine/know the colors of dinosaurs? | Other | explainlikeimfive | {
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"Most is based on speculation Others, however, are based on the preservation of melanin in certain fossil, such as *Borealopelta markmitchelli*. Unfortunately, it’s exceedingly rare for this level of preservation.",
"Speculation based on educated guesses really. We've only relatively recently become aware that some dinosaurs had varying degrees of feathers or feather-like structures. So there was a huge change in how these dinosaurs were depicted. But for the most part, it's educated guesswork. We can look at how contemporary animals camouflage themselves in environments that resemble those of dinosaurs for instance. It'll give us some indication. But at the same time, camouflage varies a lot. Baby deer are dappled with white spots like sunlight spotting the ground through the tree canopy. But in the same forest, a tiger has vertical stripes to resemble varying colours in vertical growth. So we can guess based on recurring themes and patterns we see in nature and connecting those to an animal's environment. But it's never a sure thing. Nothing about a zebra's skeleton or living habits would suggest that it's bright white and black stripes for instance.",
"We have no idea. We originally thought they were reptilian so we have them reptile like looks and colors. Someone in the last decade we figured out many are bird like and have feathers.",
"There is no way to tell; there are impressions of skin (for example we have impressions from Carnotaurus) which include samples of feathers and rough scaly texture but there's no color. Color is speculative and scientists will mostly look to nature to find answers. Reptiles and amphibians are a good start and this is what was mostly used in the past. Large mammals like elephants, rhinos and hippos were also used leading to the idea that dinosaurs would have been mostly drab, consisting of earth tones (the first three Jurassic Park movies come to mind when thinking of this). Once the link between dinosaurs and birds was established and the discovery that many dinosaurs had feathers science started looking at birds for color inspiration. Many modern depictions have wild patterns and colors similar to birds. Personally I would think it's somewhere in between; some probably had striking colors and patterns while others were probably more drab.",
"They could well be. We base it mostly on reptiles we know wich are typically brown or green for blending in with their enviroment. They could very well have been more colourfull, we simply don't know."
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nowtxx | why it's a crime to buy stocks based off insider information? | You are just using a little rumour to help you out, what's the harm in making a few extra bucks by knowing a thing or two about a certain company? | Economics | explainlikeimfive | {
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"It's not \"a little rumor\", it's hard facts only known to you because of your position. It's akin to watching a lottery drawing before it's aired, and buying a ticket after that. Insider trading is something very different than just being good at judging a company's moves or the overall economic situation. It's specifically if you're using restricted information to make your calls.",
"It’s not a rumor if it’s insider trading, you would have internal knowledge that isn’t made public, imagine knowing ahead of time that X company invented a product that was going to be highly profitable or was about to be acquired by Google, you would put a ton of money into it because you *knew* it was going to happen. The reason Martha Stuart for jailed was because she tipped specific investors about her company doing poorly, so folks removed their money before it sank with the companies value. Any other investors would have blindly invested, and watch their money sink with the ship.",
"Those few extra bucks are taken away from other people selling their stock right now, probably at a rather high price that the stock was unlikely to hit, stock that would have otherwise been unsold had you not bought the stock. They are the ones who lose in your few extra bucks scheme. The market works on the principle that everyone has access to the same information. If this was not the case, the only people with insider information would profit, everyone else would lose money if it was a widespread issue. A few shares in the grand scheme of things might not matter but if it were a bigger problem then no one beside insiders would be able to profit in the market. The spirit of investing as well is generally that your books should be open. The origins of stock investment were more in something more \"shark tank style\" where you would meet with some guy with money, explain your business and why you need money, and they would give you an offer for some slice of your company in exchange for your money. No one would agree to give you money usually unless your books were completely open (otherwise you have no idea what you are investing in) and they could make an informed decision about investing in your business. With modern companies, this tends to be a little more complicated but essentially to keep this spirit up all of your potential investors and potential sellers of investment have to be working off a common set of knowledge. This is why we have earnings and ban insider investing."
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nox0nd | What makes mathematics factual? | Mathematics | explainlikeimfive | {
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"The ELI5 answer is that math is more or less like a game. Mathematics is carried out by a predefined set of rules on a predefined set of objects. Because the game never changes, the allowable moves never change, and so the possible outcomes never change. Any situation in which the rules of the game are allowed is therefore subject to the outcomes mathematics applies to. So things like basic physics which work on just adding and multiplying numbers representing physical quantities are essentially universal because they are a situation in which you are playing the game, just using different words for the same things. & #x200B; Sometimes, the rules of the game do change. This can happen because we find out the game is broken (as in e.g. the crisis of naive set theory), and sometimes it happens because we find out that some other games are also cool or useful, or less controversial. Not all mathematicians agree that we *should* be playing the game that we are, and so they play slightly different games, but this doesn't effect the main allowable moves of the game. The basic things like + and x are still the same, it's that there are some weird edge cases involving things like ungodly huge infinities and what you can and can't do with them that some people object to.",
"It depends what you mean by factual. All math is based off of things called “axioms”. These are essentially statements that you just assume are true, without any proof. The axioms used for modern math are put forth by [Zermelo–Fraenkel set theory]( URL_0 ). Generally, axioms are picked so that they make intuitive sense, like saying that if two things are made up of the same stuff, they are equal (although some axioms needed for math might be less intuitive, like the axiom that infinite sets exist). In any case, everything else in mathematics is proven by using these axioms. As a quick detour, let’s go over mathematical proving. Let’s try to show that 1 + 3 == 2 + 2. Well, first we can use some addition rules (which can be proven with set theory axioms) to make 1 + 3 into 4. Now we have 4 == 2 + 2. We can apply those rules again to turn 2 + 2 into 4 to get 4 == 4. From here, we can see that the set on the left side is made up of all the same elements as the set on the right. Using our earlier axiom, if two sets are made up of all the same elements, then they are equal. Assuming our axiom is correct, 4 == 4 is therefore a true statement, which means that 1 + 3 == 2 + 2 is also a true statement. Again, this is all assuming that we treat our axioms as true statements as well. All of modern mathematics can be proven in this manner, just using the axioms given by set theory. Of course, it usually takes much longer. A good half of a book was dedicated just to proving that 1 + 1 == 2. **Edit:** *u/komandanto_en_bovajo has pointed out that a lot of that half-book was dedicated to setting up mathematics in general, and not just proving 1 + 1 == 2, so my previous statement is misleading.* Anyway, this means that, if you agree the axioms from set theory are factual (go ahead and read through them and see if they make sense), the rest of math is also factual, since you can show that the rest of math is just a consequence of those axioms. *As a side note, nothing is forcing us to use those axioms, except that most people agree they make sense, and that they haven’t led us to any contradictions or illogical outcomes yet. We used to have different axiom sets, but those eventually led to paradoxes, sort of like the mathematical equivalent of saying “this sentence is a lie”. We refined our axioms to get rid of those contradictions, but ZF set theory could still have some that we haven’t found yet. Anyway, nothing’s keeping anyone from deciding they want to make a better math and making their own axioms, except that ZF seems to make the most sense as of now.*"
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nox9l9 | Why sometimes the body gets sweaty after drinking water? | Biology | explainlikeimfive | {
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"I’m curious as to why I always sweat after taking a shower even if the water is not that hot…",
"Not everyone sweats after drinking water. But as you do, one of two things is happening: The appearance of water in the stomach can be interpreted as stress by the receptors in your stomach, and you sweat as a stress-response. Or, your body has been limiting how much you sweat to avoid further dehydrating you, and now perceives that you have started to drink and so it can start to sweat to cool you down properly.",
"When you are dehydrated, you do not sweat. Drinking water gives your body the fluids that it needs and you are able to sweat again."
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noxadr | - If trees release the carbon again that they have absorbed throughout their life, when they die, why do we even plant trees then? | Biology | explainlikeimfive | {
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"The idea is to not let them die. But besides that, they do a lot more than just hog carbon. They produce some oxygen, they help the water cycle (if you look at places where there's heavy deforestation you'll see lower rainfall amounts), they help soil keep nutrients for other life, they provide food for animals including us.",
"This is a system of equilibrium. The more trees are currently alive (or, more accurately, the more raw wood matter is currently in existence), the less CO2 is in the atmosphere. By reducing the total amount of wood matter, we add CO2. By increasing it, we remove CO2. Coal was largely formed by wood matter which was never able to convert back to CO2 and got trapped underground. This means that every tree's worth of coal we have burned becomes a tree's worth of wood matter that must now be sustained. Additionally, not all wood matter is 'recycled' into CO2. Wood which becomes paper or houses or what have you remains in its wooden state and does not become CO2. This is to say that renewable wood farming is essentially carbon capture.",
"They don't release it all at once. They store it in different carbon molecules that mostly get broken down by decomposers and end up back in the soil. Sure some of it gets into the atmosphere via respiration of some of the decomposers but most of it goes into the soil."
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noxd0q | When you instinctively dislike or even fear someone immediately upon meeting them, is there a biological process at play? | Two guys I've met in my life brought me out in a cold sweat instantly upon introduction. I don't otherwise have stellar instincts for people or their motivations. But I know this is something humans experience and I'd like to understand what's happening in our brains and bodies when a person, in an otherwise safe environment, manages to have this effect upon us. Is it scientific, subjective, societal, a combination? Are there "invisible" cues our senses are alerting us to? | Biology | explainlikeimfive | {
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"Not sure about the biological part, but from my experience, our brain tend to recognize traits that we've seen before in other people and extrapolate their probable behaviors. And it picks up on subtle things subconsciously. It might be the way the person acts when no one is looking, or the way they move their eyes, or their head, what they do with their hands. It may not mean anything and I can see lots of false positive detections on this system, but I would generally advise that you be very careful with anyone that triggers alarms in your brain, because our brain's non conscious processes can be very accurate sometimes.",
"I never want to tell anyone to ignore their instincts when they feel unsafe, but this does seem like the sort of question to invite pseudo-science and anecdotes of confirmation bias. Like I remember an episode of House where they say something like \"it's not a surprise you were scared of them, we're evolutionarily hard-wired to recognise sociopaths\" and I followed it up, and that's apparently 100% bullshit. This needs someone qualified in sociology to answer. I'd guess it's probably extremely complicated and nuanced.",
"What makes you think you had good instincts in those situations either?"
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noxvix | Why are NFTs making money? | Why are NFTs selling? And is this just a hype or is there really a future in unique art that only one can have an original of? | Technology | explainlikeimfive | {
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"I don’t understand how there is enough people that this concept exists. Who cares that you have an original gif or video of something? I’ve seen it too and downloaded the file to my computer for free. I think it’s mostly people who invest into the fad only for the potential to flip it to a sucker"
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noxvp2 | why does tickling ourself not work but works when other people do it? | Biology | explainlikeimfive | {
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"This is a myth. Some people are able to tickle themselves. Especially if it's an area with a large amount of nerves. Someone with sensitive feet might be able to tickle themselves with a feather.",
"You can absolutely tickle yourself but when you do your brain is expecting it and prepares for it by dulling the signals. When someone else does it, even if you know it's going to happen you reaction is more intense, which could also possibly be amplified by anticipation."
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noxy3p | In public-private key encryption, what stops someone from decrypting using your public key? | Since you know something was encrypted with someone's public key X, and you know the algorithm, why can't you reverse the process using the public key and read the message without using their private key? | Technology | explainlikeimfive | {
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"I multiplied two numbers together and got 34916677 as the answer. Without using any factorizing tools tell me which two numbers I multiplied together to get that result. You likely won't be able to unless you go try every number one by one until you hit the right answer. However if I give you one of the numbers you can easily find the other. While not exactly the same the private/public keypair are a bit like that. The cryptographic properties we're interested in are arranged in such a way that the two operations: encrypting and decrypting, are really the same operation that just happen to cancel each other out. You can't use the public key to undo the public key because you need to go *the other way*. If you walk ten miles west walking a further ten miles west won't get you back to where you started. In order to undo the public key either you have to have the private key, or you have to guess billions of potential combinations until you hit something that happens to undo the public key. There is not easy way to find that number if you do not already know it, it's all about as hard as just guessing randomly.",
"The fact that the process isn't symmetric. For example symmetric encryption is when you use the same key for encryption and decryption. Like a safe. You open the safe with your key, put stuff inside and then close it using the same key. Asymmetric encryption is often compared to a locked mail box. The mail box is the public key that you expose to the whole world, everybody can see it and everybody can drop mail for you in that. But once someon has dropped mail in it, neither they nor anybody else could get it back out. The only way to get the mail is for your to use your private key that only you have to open the mail box and take the mail out of it.",
"You can. But it takes a prohibitively long time. Public key cryptography relies on the fact that the discrete logarithm is a hard mathematical problem (in the sense that it takes a long time to compute). If you could, say, factor a very large number quickly, you could do it, but no one knows how to do that (or at least, no one has published a method for doing so). It's also possible that you could find another method to do it that doesn't involve factoring large numbers, but no one's figured out how to do that either. Using the best publicly-known methods, decrypting a properly encrypted message would take thousands of years of processor time. And for really secure applications, you can use even bigger numbers and make that into *millions* of years instead."
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noxyxu | Why do we get the urge to peel the rough skin off of a healing wound, when it will ultimately make the healing process longer and the resulting scar look worse? | Biology | explainlikeimfive | {
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"As the skin heals and a scab forms, your brain misinterprets the sensation as an itch. Scientists aren’t sure why healing skin can feel like and itch... but you’ve learned to scratch itches... so you do, despite slowing the healing process. You’re an animal responding to stimuli."
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noybeg | What does an "end in of itself" mean in regards to Kantian ethics? | Because if I'm treating people as an end such as the way I treat art as ends, wouldn't that make it not an ends because like art, I am deriving happiness from treating people as an ends just like how I am deriving happiness from doing art? So, the only way in which I could treat people as an end of itself is if I treat them benevolently without deriving any satisfaction from it because the moment I treat people kindly because it makes me happy to help other, I would be treating them as a means towards my happiness to help others and thus my action is no longer considered moral? Is that what Kant is trying to say? I don't know, his reading is very dense. | Other | explainlikeimfive | {
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"If you derieve happiness from art than it's not an end, but happiness is the end and art is a means to an end.",
"You're allowed to derive happiness from helping people, but helping people only when it increases your own happiness is treating the person as a means to an end."
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noz36q | Photons behave like waves and particles. What does this mean? | I was thinking about how a strong wind can carry sounds further and how that doesn‘t apply to light, as it moves with the speed c. Then i realized how little I understand about light and what it means to behave like a particle AND a wave. | Physics | explainlikeimfive | {
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"Really the problem is that the classical idea of waves and particles doesn’t work at the quantum level. A classical particle is like a tiny solid ball of matter, a classical wave is like a continuous transfer of energy. In reality these are both simplifications. In some cases you can approximate light as acting like a classical wave, and in others you can approximate it as a particle. The reality is that light is neither as they are both incomplete ideas.",
"Photons were a new thing that couldn't be thought of as particles or waves, but most of what they did was familiar if you knew both waves and particles. Like if you knew pretty well how to ride horses and dog sleighs, you could think of reindeer sleighs as either one depending on the issue you had until you learned the details."
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noz9rq | There have been many sculptures where the statue looks like its wearing veil. How do sculptors make stone transparent? | Other | explainlikeimfive | {
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"Veils do not have to be transparent. Their point is that you should not be able to see through them or at least not very well. So transparent vails kind of defeats their point. The reason you can see features which is hidden under a vail is because these features deform the vail wherever they touch. The sculptors just need to make the vail lay as it would on a real person and these features will show. They do have the advantage of being able to put the creases where they want, adjust the posture of the person under the vail as they want and make the wind blow the vail in the direction they want which can exagregate this effect by allowing more features to show then normally. But they are still only shaping the stone to the vail and is not making the stone itself transparent."
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nozlbn | How is it different sides of the world (Canada/Chile) can have similar trees? How did evergreens grow in both places? | Earth Science | explainlikeimfive | {
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"There is some slight variations in the trees that grow naturally in Canada and those which grow naturally in Chile. For example in Canada you might expect to see species such as Eastern Hemlock Spruce or Douglas Fir while in Chile you have species such as the Monkey Tail Tree. These species diverged hundreds of millions of years ago when the climate were completely different and have adapted with the climate to fit the local climate. It is also possible for seeds to be spread for such long distances. For example by strong winds or currents which might get seeds far away. Migratory birds could also help spread seeds very far. And of course humans have been trading seeds between Canada and Chile for tens of thousands of years. In the later years we have been doing this even more and this have become a problem in certain areas. The main reason why it is uncommon to find the same species of trees in two different parts of the world is because there is a local species which is much more adapted to the climate and will outcompete the new species very quickly. However we are now intentionally planting remote species both in gardens and for industrial uses. And when we care for these species and often grow them in large quantities they might get a foothold in the local environment. And it can be hard for the local species to get rid of this foreign invador. It might be that the foreign species is better for the climate in the short run but may not be able to survive for hundreds of years."
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np016a | do satellites orbit the earth or are they held stationary by gravity as the earth turns? | My husband and I are both in the Signal branch of the army but have very different understandings of how satellites move, if they move at all. Do they go around the earth with the rotation? Do they move at a higher rate of speed than the earth? How is it that when I use my compass, I can use the same azimuth to find the same satellite every time, day or night? Help me win this friendly debate! | Technology | explainlikeimfive | {
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"> Do they go around the earth with the rotation? Do they move at a higher rate of speed than the earth? Depends. The closer to the earth they are, the faster their rate of orbit is. Close to earn, the ISS for instance orbits once every 90 minutes. Further away you have things like Geosynchronous orbit which is a special distance from earth where one orbit is one day on earth. And further away, say the moon, orbits once every 30 days. The math governing orbits does not care about how fast the earth is spinning below the orbit. The fact that geosynchronous orbit exists just comes from the fact that the closer you are to earth the faster the orbit, the further you are the slower the orbit, and that this progressively goes from 90 minutes near earth to infinite time the further out you go, thus passing 24 hours as some point. If you want an intuitive understanding of orbits, there is an excellent game called Kerbal Space Program which really makes you understand what is going on. Its a bit silly but the physics there makes a lot of sense after playing it. I have no idea how your compass works, if I were to guess, it uses the fact that orbits are predictable and it has somewhere saved the orbital data for the orbit, figuring out its location whenever needed, this at least is how GPS works.",
"Satellites orbit the Earth. Gravity doesn't hold anything stationary, it pulls objects in. Satellites orbit the Earth at different speeds, depending on how far they are away from the surface: * Satellites at [Low Earth orbit]( URL_0 ) and [Medium Earth orbit]( URL_3 ) orbit the Earth fast than Earth revolves around its axis, therefore they complete one orbit in less than a day. The ISS for example orbits the Earth every 90 minutes. * Satellites at [Geosynchronous orbit]( URL_2 ) orbit the Earth at the same speed that Earth revolves around its axis, so they actually remain above one spot on Earth all the time. * Satellites at [High Earth orbit]( URL_1 ) orbit higher than geosynchronous orbit, so they orbit slower than Earth's revolution around its axis.",
"Satellites orbit their planets. The way this works (for circular orbits, which are the relevant ones here) (in Newtonian theory) is that they move around so fast that the centrifugal force (it's a real force in a rotating F.O.R. . Don't @ me) is equal to gravity, and as such they balance each other out. Because centrifugal force is proportional to the distance form the centre of the planet, this means depending on the distance from the planets centre of gravity satelites need to orbit at different speeds. In low earth orbit (~200-800km), which is where most earth observation, spy and scientific satellites are, this speed is around 7 km/s. A satellite in LEO will orbit around the entire earth once in around 70-110 min. However there is also a type of orbit called geostationary. This is an orbit where a satellite moves at such a speed that it orbits earth once in 23hours56min (siderial day), and since the earth also spins around itself once in the same time, a satellite in an equatorial GEO Orbit will always remain above the same precise point on the ground. This orbit is used for communication and TV Satelites, because it allows you to aim your Satelite dish at them, and not have to move the dish to track the satellite because it's completely stationary relative to a point on earths surface",
"Think of it this way. If you throw a ball along the rotation of the earth, it stays above it for some time, but it eventually falls to the Earth. But what if you threw it so hard that the curvature of the Earth starts to fall away just as fast? Well then you have an orbit. An object in orbit is moving sideways so fast that, even though gravity is pulling it back towards the Earth, the Earth is falling away just as fast as the object is falling towards it.",
"It depends on the satellite. Most stuff in orbit will move across the sky so fast that they are basically constantly falling towards earth and constantly missing because they moved sideways so much. There is however a sweet spot where the satellites are so far away that the speed at which they orbit the earth is exactly the same as the speed at which the earth turns. This is the geostationary orbit and satellite in such an orbit always will remain in the same place above the equator. You can point a satellite dish to a point above the equator and won't have to move it to remain connected to such a satellite. This is the type of orbit where most satellites used for communication are. The main downside of this is that they are really far away, which is bad for things were latency matters. They also don't prove as good coverage if you are far away from the equator. The starlink service that has been in the news recently uses satellites much, much closer to earth. Because they are so close they appear to be constantly moving all the time in respect tot he ground. This requires constantly switching between satellites to stay connected.",
"The orbit of a satellite has very little to do with how fast the earth is spinning. Especially for satellites smaller than something like the moon. The lower something is the faster it orbits. Low Earth Orbit is defined as taking less than 128 minutes to go around the earth. This would be true if days lasted 12 or 48 hours as it is 24 hours. The spin doesn't matter, just the mass. Satellites that are higher orbit slower. There are orbits that just so happen to have a orbital period of about 24 hours, which just so happens to be the same time the earth takes to spin. These are called geosynchronous orbits. Because of they were launched into these orbits, they come back to the same position at the same time every day. There's nothing special about them in a physics stand point. It's just that rocket scientist did the math and launched them that way precisely so you and your dad could point a dish at a point and always get access to the satellite. Now there is a precise band of geosynchronous orbits that has the same period as a day, is perfectly circular, and is also the direction the earth is spinning (IE directly over the equator). This is called a geostationary orbit, and it's where a lot of comm satellites are put. Because from the perspective of a person on the ground the thing isn't moving."
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np1h7o | What would be the last place(s) with water in case of a widespread (extreme) water drought? An apocalyptic scenario, but just for the sake of argument. | Earth Science | explainlikeimfive | {
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"The 2 biggest fresh water reservoir are located underground in South America, the biggest one is in Brazil, known as \"Alter do Chão Aquifer\", and is estimated to provide fresh water for world population for 250+ years in case of shortage. The second one covers Argentina, Brazil, Paraguay, and Uruguay and is known as \"Guaraní Aquifer\" and could provide 200+ years of fresh water. Other estimatives say if world population stagnate at 7 billion people in the future each Aquifer could provide around 1500+ years of fresh water. Edit: Also every continent has some aquifer system beneath the surface.",
"Underground. If everything on the surface had been used up the last go go would be our largest aquifers, places like the Ogallala aquifer",
"The last places to get fresh water (I’m assuming you’re talking about fresh water) after everything else has evaporated away would be glaciers and polar ice caps. So Antarctica, Greenland, Arctic Ocean, places like that."
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np1kii | Why is it that when we drop a vegetable into brine, the bacteria that pickle the veg are always probiotic? | Biology | explainlikeimfive | {
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"You are right that there are lots of different bacteria which could infect the solution. Some of them are toxic while others are not. But this is why we use a specific brine solution. We intentionally create an environment with the right salts, neutrients and acids that the bacteria we want prefer."
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np43vq | Why can't our thumbprint change even if it had a scrape and healed? | Biology | explainlikeimfive | {
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"Your fingerprint exists in the lower layers of skin. If you only ever damage the surface, it will grow back exactly as it was. However, if you damage the lower layers, your fingerprint will be altered by scar tissue.",
"If the dammage is deep enough it can affect them. Fun fact: your ear print, tongue print, dental impressions and irises are all unique to you and can be used for identification too.",
"It can, if taken to another level. Fingerprint mutilation is nearly as old as the practice of fingerprint identification. People use many different methods to try to remove fingerprints. Cutting or sanding them off or burning them with cigarettes or acid is common. Underworld physicians even assist with surgical procedures",
"My thumbprint changed. I sliced it open on a can of spaghetti Os when I was 10. it healed across the cut and 30 years later it’s still there."
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np4brj | why do our bodies do things like pick scabs, scratch rashes, etc. when we know it’s bad for us? | Biology | explainlikeimfive | {
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"text": [
"The mild pain associated with picking a scab also releases endorphins, which can act as a reward. Scab picking, like many grooming behaviours, is also a displacement activity that can help to distract us when we are bored, stressed or anxious."
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np5cps | Why does dark skin protect against the sun? Why can’t pale skin do the same? | I know melanin plays a role. But I also know dark surfaces attract more heat. Wouldn’t attraction of heat be a disadvantage in hot climates? What is it in *dark* skin that makes it protect against sun damage? Why couldn’t the skin be pale and have the same properties? I know people in northern latitudes are pale to absorb more vitamin D but I don’t see why dark skin couldn’t do this. What role does the color play specifically? | Biology | explainlikeimfive | {
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"Melanin absorbs UV radiation, protecting the more sensitive molecules (like DNA) in the skin. I guess it makes you absorb more heat energy as well, but that’s manageable, unlike skin cancer which results from UV damage on DNA.",
"The dangerous part of sunlight is UV radiation because it carries enough energy to alter our DNA. So if we expose ourselves to a lot of UV radiation we risk getting cancer or other gene defects. To protect from that our body produces Melanin in the outermost skin layer that absorbs the UV radiation, before it harms your DNA. The heat itself is not the problem, our body has effective ways to deal with heat. Dark skin can't also produce Vitamin D with sunlight, because it is especially UV-B radiation that is needed to produce it. So dark skin acts kind of like a shutter that closes, so it lets in enough light for the body to produce Vitamin D, but not too much to increase your risk of illness.",
"Not so fun fact. Black people can get sunburns. As my aunt found out on her vacation one year. It may take longer. It's still possible though."
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np5w06 | why does wet sand stick together? | Chemistry | explainlikeimfive | {
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"Damp sand sticks together because water forms little grain-to-grain bridges. Surface tension--the same force that lets some insects walk on the surface of a pond--acts like rubberbands between the grains. Adding water to damp sand fills spaces between the grains. The bridges vanish and the sand begins to flow more easily.",
"Sand particles are quite small, so they have a relatively low volume/mass compared to their surface area (square-cube law). That’s important. Water undergoes strong cohesive (which is responsible for surface tension) forces with itself due to hydrogen bonds, and it also has strong adhesive (sticking) forces as a result of induced interactions with silicon dioxide - also called wetting. These forces help the light sand particles to stick together, especially when you look at the scale where water is extremely effective for this purpose - as opposed to say ball bearings, pebbles, or golf balls.",
"Because water sticks to water, and water sticks to sand. And because sand is rough and hard, and doesn't slip past itself (it rolls instead), the combination can't move much, so it's stronger than just the sticky water."
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np6kfg | how does curing something like salmon or ham actually work and make it safe to eat? | Chemistry | explainlikeimfive | {
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"Whatever curing agent is used (salt, sugar, honey, smoke, etc) draws out excess moisture and creates an environment where nasty stuff that can make you sick can't survive.",
"Short answer: salt kills microbes. Long answer: by increasing the salt and solute concentration in a piece of meat, osmotic pressure will pull water out of any present microorganisms, killing them or at the very least inhibiting their growth. Some, but not all, meats are also cured with the addition of nitrates and nitrites, but these are relatively toxic to humans and are possibly carcinogenic, so their use is declining somewhat."
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np6mzd | Whats the difference between counting cards and just being really good at a card game? | I understand why casinos kick out card counters, the casino wants to make money and card counting is "cheating". But if you are able to do it all in your head, is that not the same as being really good at poker? Knowing whats left in the deck and estimating your opponents cards based of that info and by reading your opponent. How do you prove counting vs skill? Is it just a way for casinos to weed out people who would take a lot of money? | Other | explainlikeimfive | {
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"Counting cards is, indeed, just being very good at a game. It is not \"cheating\" in the sense of violating the rules. Casinos kick out card counter not because they are cheating or doing something illegal, but because the casino is losing money on them as so has decided to decline their custom. Think \"we reserve the right to refuse service.\" The casinos, which are private businesses, are using that right.",
"They kick them out because the casino is a private business trying to make money. Though in practice, kicking people out for card counting is rare. A lot of casinos now just changed the rules slightly for games like blackjack that increase the house edge to the point that card counting doesn't help much. And at ones that haven't, they really don't care if you're just betting $50 in every hand.",
"This is nearly a myth. Casinos almost never kick out card counters. Casinos will, on rare occasion, remove someone who they think is not a good customer - which includes *some* card counters. Most people who try to do card counting will never make money with it, and will just boost the casino's profits. Making money with card counting is wildly over-glamorized in popular media; it is not sitting down with $100 and walking away with $1000 after an hour. In order to make money at all, you have to pay close attention to the whole game and play in a very unusual way. You need to bring in a large bankroll to be able to weather the ups and downs, because you're still gambling, you just have a tiny advantage. You need to not drink anything or get distracted by the casino's plentiful distractions, or you'll lose focus. And there's a bunch of techniques the house can easily apply to cut off your advantage, ranging from increased decks (which reduce the edge) to continuous shuffling (which just makes card counting pointless). Further, even if you pull it off and make a few hundred or thousand dollars on the blackjack table, you need to have the discipline to then leave the casino with that - and never get drawn into the other games that will just drain your money again. So a lot of people think they can do card counting, and try to do it casually, and end up playing more & losing more money than they would otherwise. Overall, the concept of card counting is actually beneficial to casinos. I would not be surprised if some of them actively push the \"we kick out card counters\" concept in order to increase the feeling of \"thrill\" that people get from \"getting away with it\" - drawing more people to try it out and lose more money.",
"Casino’s only run games if the expected return of the game favors the casino. “The House Always Wins” means in the long run, every game makes the casino money. For a game like blackjack, you can actually develop a betting strategy where the expected return favors the gambler. But the strategy requires you to track whether or not cards have been used by “counting cards.” But since it’s private property, casinos can remove you for any reason whatsoever. So if they suspect you using this strategy, they will usually kick you off the casino floor because they only care about money.",
"Card counting is indeed a skill and is just being really good at the game. The reason card counting is made illegal by the casinos is indeed just because they are losing money on it. All the casino games are designed so that the casino is on average making a small profit from every bet. The best example is roulette where betting on red or black would give you double your bet if you win. However the casino have added one or two green numbers where the casino always wins no matter if you bet on black or red. Blackjack is also designed to give the casino a slight advantage although it is less obvious. However it turns out that there was an error in their calculations and they did not consider that players could count the cards and know the distribution of the cards remaining in the deck to get a slight advantage of their own. This is just players being good at the game. There were some attempts at fixing the game but to no avail. But since casinos are private property they can just throw out anyone who is good at blackjack. In places with legislation that does not allow them to throw out people without any reasonable cause they will not have blackjack at all.",
"This discussion misses the most important part of counting cards that Casinos recognize. Changing bet size. When counting cards and odds begin to swing in your favor you begin to bet much larger -- naturally. You also make your bets as small as possible when odds favor the house. This is the dead giveaway that you're counting and taking full advantage of it. If you counted cards and never varied your bet size you wouldn't make any money because you're not taking advantage of your advantage.",
"Casinos very rarely kick out card counters.Card counting is not considered cheating if you can do it in your head and don't use an outside device. Even with card counting, you are very likely to lose money, albeit less than the average joe. Casinos rely on reputation, so they don't wanna be kicking people out left and right. In Blackjack, there's a standard technique where like if you have a 4 and a 10 and the dealer is showing a five, you stay. If you have 14 and the dealer is showing a ten, you hit. Your loss rate with standard technique is like. 2%. A 2% loss rate on casino games means if you bet $1, 100 times, you'd end up with $98 dollars. *And that's really good for a casino game* If you add in card counting you could profit maybe 2% (so, $1 x 100 instances of betting = $102, $2 profit). (It should be noted most people aren't savants and don't actually memorize every single card that comes out). Blackjack is the game where you are least likely to lose money. Craps is second and I believe the loss rate is like 12%. But, 2% is really not a huge deal. If you had a pot of 100,000, you would make 2,000 a day *if* you played perfectly, never had bad luck, and played for hours and hours and hours. And you aren't getting comped drinks or food. Pros who are making a slim profit on the casino make suckers think they can do it too.",
"With poker, the casinos have a system which guarantees a profit. With blackjack, the same thing is true with the exception of card counters. Blackjack with card counting is a game that the casino isn't willing to play.",
"My friend openly counts cards and nobody has ever said a word to him. Counting cards only gives you a slight advantage, but it’s a lot of work. You can’t even really make much money at it because of table maximum bets. Sure, if you find a super high limits table and are doing too good, they might kick you out. But even more likely is they will get you a room and a drink. TLDR: For the average person, there is nothing wrong with trying to count cards.",
"A better comparison game for card counting is Hearts. You absolutely have to count cards to be good at Hearts. That also applies to Spades, Bridge, Whist, and no doubt many other card games. Poker is not a good analog because being good at poker involves many skills besides understanding the odds of a particular card coming out. In BJ, the dealer is playing by a fixed set of rules and does not make decisions, whereas in poker, it is all about understanding what your individual opponents may or may not do.",
"From what I understand when I was trying to learn to count cards in blackjack, casinos don’t kick people out for card counting. They kick people out for using a device to help them card count. Doing something in your head is just what people already do whether they’re good or bad at it. Plus counting cards only works with specific conditions. Like the more decks they use the better since they usually don’t shuffle until they’re near the end, but counting cards really isn’t possible with 1 or 2 decks due to the lack of time the counting of cards would actually benefit you. The reason casinos even use multiple decks is so they have to shuffle less and get in more games, but for high stakes games or tournaments then they’ll just use one deck where counting cards won’t work. The people that the movie “21” is based off of and have a course on how to do it with stories that seem to go against your assumption."
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np6pdp | How does stretching or rolling muscles out help them feel better? | Biology | explainlikeimfive | {
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"Your central nervous system is telling your muscles to “tighten up” because it thinks they need to be tight to avoid injury or harm. Stretching and rolling out can help with the perception of loosening them up, but really it’s your CNS telling them to relax. That’s why you feel better after moving around and stretching when you’re sore because your CNS is toning down. Edit: I apologize. Your autonomic nervous system is toning your muscles down. Source: URL_0",
"What I'm understanding from these replies is that after exercise when the muscles are tight, it tricks the Central Nervous System into letting the muscles go.",
"It loosens the tightness between the myofascia and the muscles. It should be all slippy and slimy but it can get dry and sticky. myofascia is the membrane of tissue that surrounds all muscles and organs.",
"But why do they ache in the first place?",
"You got little guys in your muscles that sense if the muscle is lengthening (stretch) or shortening (contraction) and they work together to make sure the muscle doesn’t go in a position that would hurt it. When stretching, those guys feel the change in length and in return send signals to the nervous system that will tell your muscle to relax. But if you stretch too much, the other guys sense it and make sure your muscle contracts to protect it. And there’s also a release of hormones following that, and this all contributes to tricking your body into feeling better!",
"What I have learned from this is that nobody really knows what’s going on. Nonetheless the results speak for themselves: doing some sort of stretching / mobilization can make you more flexible.",
"So far, no one has said anything that is supported by evidence. We only know that individuals report that they “feel better” but there is no quantitative (measurable) changes. This is also hard to compare to a control group in studies. Honestly it’s likely only placebo.",
"I thought it had something to do with spreading lactic acids through the muscle as lactic acid makes muscles sore so rolling it out dispersed the acid healing in faster recovery time?",
"Your muscles that are excited or grouchy from a good work out or from repeated moments of pain are told to calm down by your brain after you put pressure on them, as long as the pressure isn’t so much it isn’t causing big owchies.",
"Physics Girl has a really good video asking this exact question. URL_0 It has better answers than what I've seen here IMO.",
"Maybe someone can help me with a life long issue: I was born early and got sepsis 3 days after birth. It ruined the growth plate in the right leg. Long story short: the knee and femur were deformed and did not grow in length on its own. So I've had years of limb lengthening surgery to correct it. Issue is, due to still not being long enough, and all the muscle scarring, I can't bend my leg past 75 degrees. This is such a hassle. I want to know, if rolling these muscles may help. Like, what exactly is the issue with these muscles? They are weak, and seemingly can't bend. But also when I do sorta force the leg to bend I feel a massive stretch in my quads."
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np6y20 | Why do most deep sea creatures look like they're hell-spawns? | Biology | explainlikeimfive | {
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"They evolved to deal with conditions that are completely alien to us. As a result, they share very few traits that are recognisable to us. The animals that we find the most appealing, are usually the ones most similar to what we find cute. Usually, other mammals that are warm, soft, have eyes and expressions that we can imagine we see emotions in. Deep-sea fish are not that. For instance, there's extremely little light down there. Not enough to really see by as we do. Deep-sea fish tend to have enormous bulbous eyes. Those eyes don't really let them see things but those huge eyes might just be enough to see other fish or animals as they pass overhead and block what extremely little light filters down from the surface. Noticing that might make the difference between going hungry and catching prey, or spotting a predator and avoiding becoming prey yourself. The lack of light also means the colour works very differently down there. There's not much point in being colourful if nobody can see you. So many deep-sea fish just have that pallid corpselike absence of colour. Others are transparent to avoid casting a shadow against the faint glow of light from above. Some fish are bright red as a form of camouflage. Low energy frequencies of light are filtered out first as you descend underwater. That's why things quickly start to look blue-greenish. Red is the lowest energy frequency of light. So red part of the light spectrum is the most absent in the deep. Without red light to reflect, the colour red is basically invisible. Most deep-sea fish have completely lost the ability to see red. Speaking of prey. Without sunlight, nothing grows down there. Small animals can survive on marine snow. Basically tiny flakes of organic detritus that constantly come down from above. Slightly larger animals can eat the filter feeders that survive on marine snow. But larger animals like deep-sea fish only have one food source available. Each other. The deep-sea is essentially a freezing cold, pitch-black desert. Everything is scarce down there, including opportunities to eat. So most deep-sea fish have maws full of long needle-like teeth. Essentially they can't afford to let prey escape. So when they manage to grab prey, those maws full of needles make sure that prey can't slip their grasp. Deep-sea fish have many other adaptations to deal with the scarcity of food down there. Many fish have enormous mouths so they don't have to pass up on larger prey. Some have incredibly stretchy mouths and stomachs to the point where they can swallow prey that is bigger than they are. Others develop some truly alien adaptations like little bioluminescent lights to attract prey. Remember how red is essentially invisible down there because there's no red light? There's one predator that has its own bioluminescent red spotlight that allows it to easily find red fish in the dark. And the best part is that since most deep-sea fish can't see red, his spotlight is invisible to other fish. The weirdness just keeps going. Energy preservation is very important down there so most deep-sea fish are ambush predators that don't swim around much. As such, they don't have the neat hydrodynamic torpedo shapes we usually associate with fish. Many are just sort of shapeless and blobby to help them deal with the pressure. And they developed many other strange adaptations. When a male angler fish finds a female, he never lets her go. It's very hard to find a mate in the dark emptiness after all. Instead, he bites down on her body and slowly fuses with her to become part of her. The male is nourished by connecting to her bloodstream and slowly wastes away until the male is little more than a pair of gonads attached to the female to provide sperm for her eggs. Simply put, the deep-sea is a completely alien environment that places very unusual demands on its denizens. They look frightening and alien to us because nothing about them makes sense to us in the context we're used to. Their proportions are bizarre, their eyes are disturbing, their teeth look like a nightmare. But for them, those are just the tools they need to survive the world they live in.",
"Part of it is a lack of need for aesthetics that match our own and part of it is that we hardly see them. They don't have common traits we see on the surface so we see them as otherwordly, there is hardly a point in having good eyesight so their eyes look weird, food is scarce so their bodies look weird, their body doesn't need to adapt to reflect sunlight a certain way so their skin looks weird. These are all factors that make them look different to most animals that live closer to the surface and since they are so rare for a common person to see (meaning not popular in the media) then they catch the eye quickly. If you think of any animal you can see how weird they can be, giraffes have really long necks and are super tall, elephants have long noses and funny looking ears, whales are super big and breather through their back with some species feeding out of millions of microorganisms a day, chameleons have independent eyes and can change colors, some octopuses can basically blend perfectly with their enviroment by changing their skin, birds can detect magnetic lines to navigate the planet and the wandering albatross can fly for years without ever touching dry land. But since these are all common and they share some traits with us due to similar living conditions (mostly how we have a need to adapt to sunlight and a way bigger food supply for all) we don't see them as weird because they just look natural. But from an alien's point of view the whole planet is weird.",
"I believe its the otherway around. Artist (and now societal) depictions of demons and scary things has been heavily influenced by creatures. Just imagine being in ancient times and seeing a dead sea creature that has washed to shore- its the stuff of nightmares. Sidenote- depictions of hellish creatures having goat-like features may come from christian painters giving demons the characteristics of the greek god Pan.",
"To add to what others have said: In some cases like the [Blobfish]( URL_0 ), they actually have a somewhat normal appearance in their extreme deep sea environment under 1800psi of water pressure. When they're brought to the surface at 15psi of atmospheric pressure they turn into a gross blob. You wouldn't look so hot exposed to the vacuum of space either, and that's 120x less of a change in pressure than poor ol' blobby.",
"Alongside what /u/Arclet__ said, the other reason why they're so hideous is because they're literally optimized to butcher and kill each other. In the bottom of the ocean there's no plants, the closest herbivore analogues being scavengers. It's literally dog-eat-dog in a hellish environment where energy and food is scarce, so these creatures evolve to 1) spend as little energy as possible by drifting for the most part in the infinite dark, 2) have a mouth as large as possible, horrific teeth that WILL sink deep into prey to prevent escape, and jaws that unhinge and swallow in split seconds. These make the difference between life and death in the abyss.",
"I don’t think there’s a reason for it - animals evolve to thrive in their surroundings, and looking pleasing to humans isn’t high on their list. Beauty is in the eye of the beholder though - maybe we look just as creepy to them :) Edit: corrected spelling",
"It really doesn't help that a lot of the pictures you see are after they've been rapidly decompressed. If you see one at the surface, it's organs have likely exploded and it's features distorted.",
"Creatures look like they do up here, because they are seen by other creatures and their own species, they evolved to look nice and display their patterns and colors. Down there there is no light, they don't need to look all fancy, because no one can see them.",
"Because the physics they're working with is different. Theres a lot of videos circulating around youtube of marine biologists who can't readily identify even well known species on camera simply because of the way they move or contort themselves, like how gulper eels can inflate themselves and squirm around because living deep under water makes that both possible and a thing there are advantages to doing. Same for how large whales can orient themselves weirdly when they sleep or prepare for mating and sometimes their reproductive organs get taken for weird sea monsters by some sailors. Or how some fish can have asymmetrically positioned eyes or eyes that see through translucent skin. All of these features are bizarre to us but make sense to those creatures because they play by laws of physics where moving in three dimensions is the norm, gravity matters less than the behavior of the water they're in for movement, and the amount of oxygen and nutrients they can access varies wildly by much more than on land. This is also why humans generally need lots of equipment that looks weird and a lot if specialized training to get very deep. The pressure of the ocean will destroy the human body a million different ways because the human body isn't designed for that environment and even with equipment safety procedures need to be followed going down and coming up. But these weird creatures can spend most of their lives there because their bodies are adapted to handle it.",
"There are a lot of good answers here already but something I want to add (as someone who works in this field) is that I think the 'deep sea creatures are scary and hellish' narrative is a bit of cherry picking. [There]( URL_3 ) [are]( URL_4 ) [plenty]( URL_1 ) of scary looking animals that live in shallow regions and [there]( URL_2 ) [are]( URL_0 ) [plenty]( URL_5 ) of cute or beautiful animals that live in deep waters. I have a theory that everyone has at least a little bit of thalassophobia and sharing the scariest deep sea animals around helps confirm that bias.",
"At the bottom of the sea it’s both immense in both pressure and darkness and so their bodies have adapted to both of these by getting all hellspawnish and losing things like eyes and whatnot. For an even simpler explanation shits heavy down there and they have no one to impress and so they all just wear whatever works.",
"A few reasons! * They have to deal with extreme pressures, which mean organs get pushed around into weird shapes * Since there is almost no light, they either need large eyes or rely on other senses * Since life can be scarce at certain depths, they have evolved to be very good hunters at finding a specific food source. That usually means that predators have long, sharp teeth to grab on to slimy fish."
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np7hfp | How do companies that focus on space make money? | I understand that there are lots of odd inventions that we use everyday that come from places like NASA but I don't understand the point. What are we learning thats so important? | Technology | explainlikeimfive | {
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"There are companies and governments who need satellites - everything from military reconnaisance to crop monitoring, mapping, weather forecasting, scientific research, navigation, communications and so on. Those companies and most governments don’t have their own launch capability, so they have to pay someone to get their satellites up into orbit. •The rocket companies make money from launch fees. •The satellite companies pay launch fees - but make money from businesses and governments. •The businesses pay for satellites to be designed, built and launched - and make money from services that satellites allow them to offer. •The governments raise taxes to pay for the services and scientific results they produce.",
"Not sure if you're just using NASA an example, but it's not a company and doesn't have a mandate to make money. It has generated a fair bit of revenue in patents and licenses from things its had to invent to get to space, but it's not driving that on purpose. The direct answer: some of them are not making money - today. They are funded by investors to operate on the promise that they will some day before the first companies able to do things in space. You can't just up and build a rocket to the moon. There is a lot of very specific expertise and infrastructure required. The companies already doing that will be the first companies to open space hotels or mine meteors. There are a bunch of companies that can make photocopiers now. But, if you'd been an early investor in Xerox you likely would have enjoyed a long run without competition. Investors are banking on that with some current space tech companies. To add to that, some space tech companies make money by doing things that are impractical for NASA - ferrying commercial satellites to orbit, taking supplies to the ISS, taking tourists to orbit etc. The question of what we're learning is a bit more nebulous. We're learning lots, when conducting experiments you always have to try to control as many variables as possible. But the fact of being on Earth introduces it's own variables. For instance, we've learned that plants only use certain colors of light that happen to be present in sunlight, so we can grow under artificial light much more effectively. We've learned a lot about how gravity affects our bodies. We've driven the limits of computers and advanced our understanding of how flight works. A lot of the drive to smart devices has been supported by wide spread satellite availability. Etc etc. The biggest take a way is that companies don't need to make money if investors are willing to buy their future promises. So space companies that don't have practical functions now are making money by selling shares. For a great example of this read about how Amazon was built, it's only just started to turn a profit, it lost money for more than a decade but was a darling of the business and investing world.",
"You can group what we learn from our adventures into space into 2 really broad categories. 1. Solving engineering problems in space (or space adjacent) often results in stuff we can use on earth. Space presents unique problems for engineers to solve and a lot of times those unique problems and solutions turn out to be really useful for us on earth. Probably one of the biggest things is the CMOS sensor, in other words digital cameras. Another is artificial heart pumps used in surgeries. We could develop them because of the software NASA uses to simulate fuel in rocket engines. This has permeated our society, pretty much all technology you use today got advanced in some way or form by NASA and NASA-related work. 2. Basic research. This is stuff that expands our fundamental understanding of the universe, which in turn lets us create new technologies. Sometimes this doesn't turn into something useful for decades or even centuries. Remember, technology at the end of the day stands on the shoulders of giants. Humanity has known about electricity for centuries. But couldn't really use it for a lot of things for a little more than a century. Today we literally could not have modern society without it. We never know what basic science will be used for in the future."
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np7kex | How did the Romans do complex mathematical calculations with Roman numerals and without using zero? | Mathematics | explainlikeimfive | {
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"The Romans mostly used math for practical purposes...accounting, construction, engineering. And Roman numerals don't have place meaning...an M is 1000 no matter where it is. As a result, they didn't really need an explicit zero. And addition, subtraction, and multiplication in Roman numerals isn't hard. Somewhat tedious if you're doing large values, but once you're used to it not really any worse than memorizing times tables (which you don't have to do for multiplying Roman numbers). Division does suck...but they had abacuses. And abacuses inherently do place-based numbers. So if you needed to do \"heavy\" math you'd just use an abacus and that takes care of most of what makes it look like it would suck if done by hand. Uncoincidentally, the Romans didn't do much with pure mathematics. But that wasn't what they were trying to do either.",
"They mostly didn't. Mathematics in antiquity was mostly the physically practical forms of math. Things like arithmetic, basic algebra, and basic geometry. More complex mathematics such as advanced geometry, advanced algebra, calculus were not invented yet.",
"Doing numerical operations on Roman numerals was tedious, and in general they avoided it. Instead, if something needed to be summed they would use an abacus. For engineering applications, they typically used geometry, the tools of which were a straight edge and a semicircle and can be done entirely without using numbers."
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np85og | How do wild animals keep from dying of infection from wounds and open cuts? | Biology | explainlikeimfive | {
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"Animals have immune systems and blood that clots, stopping wounds so they will heal. This is the same as with humans. If these things don't work the animals die."
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np8dts | Why does a Leyden jar discharge quickly and a battery slowly? | I don't really understand the difference between the two | Physics | explainlikeimfive | {
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"A Leyden Jar is a type of capacitor that stores the energy in an electric field. Like any capacitor it can discharge quickly. It also has a relatively low energy density. A battery stores energy as a chemical reaction. When it discharges, the chemicals in the battery transform. This is a much slower process. It also has a much higher energy density."
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np8umu | Why can't irrational numbers be expressed as a fraction | I know one of the criteria for an irrational number such as Pi or Phi is that it can't be expressed as a fraction, or a ratio of 2 numbers. Why though? | Mathematics | explainlikeimfive | {
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"Because rational numbers are defined as being able to expressed as a fraction. Since irrational numbers are any real number other than rational numbers, it cannot be expressed as fractions",
"Well it is not a why really, this is how we define them. We know that there are some numbers that can be expressed as a fraction (ratio) and we call them rational. And we know there are some numbers that cannot, so we need a name for them too. So we call them irrational! There are also other very interesting questions on that subject, for instance how do we know rational or irrational numbers exists? There is also a concept of algebraic or constructible numbers which is often discussed in conversations like that. I hope this answers your question a bit!",
"Irrational numbers have an infinite, non-repeating string of decimals. Because of this, to represent it as a fraction you would need an infinitely long number over another infinitely long number. And even then, those numbers would still have decimals after the decimal place, meaning they wouldn’t be integers. This can be seen with 1/3, which is an infinite REPEATING string of .3333333.... No matter how many magnitudes of 10 I scale this up by, I’ll still have the exact same tail of 3’s after the decimal. But since the decimals repeat, we can use a little trick in base 10 where we take the repeating string and divide it by 9’s of the same length. So .3333333.... is equal to 3/9. Likewise, 0.142857142857...... is equal to 142857/999999 = 1/7 Irrational don’t behave this way, and no two integer ratio will exactly equal an irrational number.",
"To use an analogy, it’s like asking “why can’t a triangle have more than three sides?” One of the things that makes irrational numbers irrational is that they can’t be expressed as fractions, much as one of the things that makes a triangle a triangle is that it has three sides."
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np97r7 | Why do people laugh during mental breakdowns? | Why is it that when people have mental breakdowns or psychotic episodes they may burst our in uncontrollable laughter? What's the link between laughter, something associated with joy and happiness and a mental state of stress and anxiety? | Other | explainlikeimfive | {
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"From personal experience, I laughed because I felt so ridiculous. But from what I pulled off wiki - Paradoxical laughter is an exaggerated expression of humour which is unwarranted by external events. It may be uncontrollable laughter which may be recognised as inappropriate by the person involved. It is associated with altered mental states or mental illness, such as mania, hypomania or schizophrenia, and can have other causes.[1][2] Paradoxical laughter is indicative of an unstable mood, often caused by the pseudobulbar affect, which can quickly change to anger and back again, on minor external cues. This type of laughter can also occur at times when the fight-or-flight response may otherwise be evoked. The more you know.",
"Stress produces hormones that help you fight or run away from a situation. There is no fighting or running away from mental stress because it's in your head so the body produces an extreme amount of hormones to the point your body breaks down. Laughing produces the hormones that reduces the stress hormones. Sometimes when a mental breakdown happens, what happens externally confuses the brain on how to interpret it. This is called absurdity. Most people laugh at absurd things. With the amount of hormones going thru the body during mental breakdowns trying to counteract each other, the absurdity triggers the maniacal laughter. It's a way for the brain and body to cope."
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np9h5e | If I completely shut down a computer and not use it for months, how can it still tell the time accurately? (given that it isn't immediately connected to the internet) | Technology | explainlikeimfive | {
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"Most if no all computers have a battery backup for stuff like that. If you turn your computer on and the date and time is wrong that battery is dead.",
"A computer's motherboard has a battery, known as the CMOS battery. This battery remembers all the basic BIOS settings on a computer and keeps track of the time and date. If you remove this battery and leave it off for a while you'll notice all BIOS settings have reset and your time will also have to be re-synced.",
"You are not shutting it down completely. CP has a battery on the motherboard that is there to power the real-time clock and to keep bios setting. For a desktop, it is often a button cell battery that is easy to switch but in a laptop, it is often soldered on. Just looked at a motherboard like [one of ASUS's current models]( URL_0 ) and the battery is trivial to spot. It is the large silver-colored circular you seed in just to below the initial P in \"ProArt B550-CREATOR\" that is printed on the motherboard.",
"Inside the computer there is a battery on the motherboard. It provides the power to the current settings of a program called BIOS. BIOS is a simple program that has a handful of settings that in the end, tell the hardware in a computer to start up everything and load Windows (or other operating system).",
"They're never truly off. CMOS battery. It keeps the board alive with a tiny amount of current to store settings and keep time. If you're going to store a machine for more than a year, pull the battery. Sometimes they corrode.",
"Not all computers do this. I've tinkered with a Raspberry Pi 3, and it absolutely always needed to stay powered on or use an Internet service to know the time. The difference between computers that can keep the time and ones that can't is a \"realtime clock\" (RTC) circuit or chip. An RTC is typically powered by a little coin cell battery. On a PC, this battery is usually also used to retain some of the computer's basic hardware settings in its BIOS or UEFI."
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np9z02 | Why is South Africa so prominent compared to other African countries? | I know it is still an impoverished country but compared to other african countries it seems much more civilized and developed. But even more than that it seems like it is much more culturally prominent than other african countries. I never hear about Ghana in casual conversation but I feel like I hear about South Africa more regularly. It has had major historical figures, movies have been set there, people want to travel there. It just seems like it is more out there than the rest of Africa. | Other | explainlikeimfive | {
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"South Africa is unique because : 1) We were not Colonised initially. We were a waystation for boats of the Dutch East India Co. Nothing more. That settlement became bigger and bigger as Europeans from various countries saw the opportunity to create a new lofe here in Africa. 2) The expansion or Colonization of South Africa was due to a breakdown between those who saw themselves as \"Boere\" or \"Afrikaners\" ( Meaning second or third generation immigrants) and the ruler of the what had by then become the Cape Colony. The Boers set out north to find fame and fortune but in the process creates many small wars with the indigenous peoples. 3) Eventually, After a series of small wars and a couple of big ones between everybody, The union of South Africa was created. A South African government under British rule. 4) South Africa is prominent because of our violence. The violence of Apartheid where people protesting for equal rights were shot in cold blood and the violence that stood up against it. Also, the violence of our current time which is extremely high because it mostly senseless unlike Nigeria which has Boko Haram etc. 5) We are extremely mineral rich. We have a shit ton of gold, platinum and diamonds along with amazing natural wonders and wild life. Where in other colonised countries such as DRC, the indigenous people were massacred for their resources, our people were strippes of their rights and often \"forced\" through circumstance to mine these resources. 6) We are prominent because we had nuclear weapons but dismantled them, we have won the Rugny world cup three times( suck it eddie jones), we have one unique biome that is only found here, we have Africa's only Biosafety 4 lab, we have one of the strongest militaries in Africa along with a stable economy(in the past). Source: I am A South African and I studied our history. Feel free to ask questions.",
"One part might be bias since it is one of the few countries in Africa with a significant English speaking population so you'll get more news from there. The other part is that it was one of the few African nations in the Age of African colonialism that Europeans tried to settle with people rather than just exploit and so got a major head start in development because of it.",
"European colonies generally took two forms. In some cases, a relatively small number of Europeans simply supervised native labor for resource extraction. In other cases, the Europeans were the majority of the population, having developed land or displaced populations. The latter occurred in places like North America, Australia and South Africa. As a result, the cultural, economic and technological development of such places was based on the European standard. In most of the rest of Africa, the predominant population was native. As a result, it had a cultural, economic and technological development of the native population. When independence and majority rule came, most of the Europeans left and there wasn't anyone left to maintain an industrialized society.",
"South Africa was somewhat unique as a colony because the goal wasn't (just) resource extraction, but also maintaining a military grip on the country. There was a long period where the most direct route for trade between the Indian and Atlantic Oceans meant sailing around South Africa, thus whoever controlled South Africa controlled the route. Even after the opening of the Suez Canal, South Africa was still necessary as an \"alternative\" route just in case someone ever tried to shut down the Suez. The easiest way to maintain that control involved moving a lot of Europeans to South Africa, and investing money and resources to develop the colony. In addition, the Dutch East India Company that controlled the colony initially basically wanted *anyone* willing to live in the colony, and accepted a fair number of political and religious exiles from Europe (e.g. the Huguenots) in order to grow the colony as quickly as possible. All of these various figures ended up bringing a fairly large amount of intellectual and monetary capital with them. Hence, South Africa had a *lot* of capital injected into it from the outside that many other European colonies in Africa never really got, and that is reflected in the state of the country today.",
"There are other prominent African nations such as Egypt and Nigeria which both have higher GDP then South Africa. What distinguishes South Africa from most other African countries is that it was not so much colonized as settled. In that regards it have more in common with the USA then Ghana. In rough terms the same way that British, French and Spanish settlers started farming in North America in the 1600s onward Dutch settlers started farming in South Africa, the Boers. But also local tribes learned the breeding and farming techniques brought by European settlers which triggered a huge population boom. And just a few years after the American war of independence the British invaded South Africa starting a series of wars, especially after they discovered gold and diamonds (roughly around the time of the gold and silver rush in North America). And although the Boers were relatively well coordinated it was actually the Zulu tribe who mustered the best army and ruled over a large part of the territory and fought the British, even winning notable battles. Eventually everything was under British control. But this meant that you had the unusual situation of a British colony ruling over Dutch farmers, well developed fertile lands, local tribes with well educated and experienced economists and politicians in addition to big gold and diamond mines. And that is kind of what makes South Africa a bit different even today.",
"This isn’t going to be a popular answer... but I’m guessing that it’s because South Africa has the most white people and you’re from a western country that views the relevance of history in the context of how relatable it is to other white people. There are African countries that have more ancient history, countries with more resources, countries with more relevant political events, countries with more notable violent conflicts, countries that weren’t colonized, etc. But South Africa is the only country with a sizable white population. But at least from an American perspective, the only education most people receive on Africa is that the pyramids are in Egypt (and even though Egypt is in Africa, it is usually grouped in with the Middle East) and South Africa/Mandela/apartheid. The other 52 countries are a big blank.",
"I think there are a few factors. Historically, the Cape of Good Hope was a vital stop on shipping routes. The Dutch East India Company had a major presence at the Cape for that purpose. The Cape has always been a key strategic stop for shipping. Because of the influence of colonialism, South Africans participate in many sports that are popular worldwode and have, to varying degrees, made a big impact internationally. So that may draw spotlight to the country from those activities. Also, the impact of Apartheid is major. Apartheid drew massive amounts of negative attention (rightly so) and put the human rights abuses perpetrated by the National Party government in the world spotlight. The world had an interest in the abolition of Apartheid and, I think, continues to have an interest in the socio-economic progress South Africa has made / is still trying to make because of the international knowlefge of Apartheid.",
"Just wanted to bring this to your attention in case nobody’s ever said it to you before: saying entire countries are “less civilized” is a pretty offensive/racist thing to say. From the point of view of people in Ghana, they have no less of a “civilization” than anyone else; they just may have different values, wealth, and technology in their civilization than in someone else’s. Some other, more descriptive phrases for what you might be trying to say is “wealthier,” “more covered by the news,” “more popular for tourism,” “more western,” etc. :)",
"It's just the big and rich. Nigeria has more population, as does Egypt, but per-capita South Africa is more wealthy, while still being the third largest African nation in terms of total GDP. Botswana and Gabon are wealthier still, but relatively small. In European terms, they would be like your Belgium or Luxembourg to South Africa's France/Germany. Now as to why South Africa is as wealthy as it is, I would argue the biggest reason is trade. South Africa features Durban, the largest seaport in sub-Saharan Africa. It's well-positioned to handle intercontinental shipping to South Asia, Australia, Europe, and the Americas."
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npa6cs | Why do spiders not get stuck in their own web? | Like other things can get stuck and not be able to escape, how do they not get stuck? | Biology | explainlikeimfive | {
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"When a spider spins it’s web, not every strand is sticky. Usually only every other is sticky. The spider knows which ones are and are not sticky and only walks on the non sticky ones. There are in fact 7 different types of silk that they can spin. Some are for catching prey, the sticky ones, some are for structure of the web, non sticky ones. Some are for wrapping their food up and some are for egg sacs. Others have other uses. It depends on the species if spider as to what silk it will spin when."
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npai2q | measuring neurotransmitters? | In our society today we can draw blood and determine what levels of certain things (vitamins or what not) people are low on, and then prescribe them things to make their levels “better”. When it comes to mental health/mental illness, why can’t we do something similar with our brain chemicals? Like somehow draw some brain fluid or something and see that this person is low on dopamine or serotonin and then prescribe accordingly? Wouldn’t that help the mental health community immensely? | Biology | explainlikeimfive | {
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"It's difficult to measure neurotransmitters directly, since they are quickly metabolized. But we can measure their metabolites. For example, metanephrine is a metabolite of adrenaline, and homovanillic acid is a metabolite of dopamine. These can be measured in blood, urine and CSF (fluid drawn from the spinal cord). It is used to diagnose certain tumors. These tests are not used in psychiatry, but I suppose they could be. You might need to know a patient's baseline levels first though. I did a quick search and found [this study]( URL_0 ) showing higher homovanillic acid in schizophrenic patients, and [this study]( URL_1 ) showing higher metanephrines in ADHD patients."
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npanpy | What causes faired skinned people to either tan/burn/just stay the same. | For example, me and my partner have been out all day. My skin is fairer than his but I have no signs I’ve been out in it but he has burned his shoulders. | Biology | explainlikeimfive | {
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"Paler skin basically reflects the UV rays. A burn occurs when the UV rays damage or mutate the cells and the skin that's damaged gets flooded with blood to try and repair the cells causing a sunburn or something along those lines. A tan, usually you need at least a little bit of melanin and when the cells are damaged your body overproduced more melanin to try and protect itself from further sun damage Getting lighter with age isn't uncommon among Latinas and Asians. I'd still recommend using a sunscreen because certain rays are still able to penetrate the skin and can cause damage in the long run."
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npb401 | How were medieval navy commanders able to communicate with 100's of ships during war? | During medieval navy wars, there was a lot of smoke and noise from cannon fire. The weather was sometimes stormy. The visibility and sound wouldn't have been that good. How were they able to command ships during such conditions and keep updated with rapidly changing events during battle? | Other | explainlikeimfive | {
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"Using signal flags. A pair of flags used by a signaller in different positions can be used to spell out the alphabet URL_0",
"> medieval navy wars Didn't happen a lot. Naval warfare mostly happened earlier (roman times) or later (post rennaisance) But in general they didn't communicate well. They used flags for signalling, but even in WW1 miscommunications were still very common. So everything basically boiled down to whose pre-battle plan fitted the conditions of the actual battle better.",
"Most of the communication was done with signaling flags. Either they would hoist a string of various flags up in the mast where each flag represents a character but often a special signal determined beforehand. You could also have sailors standing on deck waving two flags like a semaphore. Sometimes the ships would be close enough that in a silent moment the captains could shout to each other. But a lot of it was down to organization beforehand. Each captain would be responsible for their own ship and make decisions based on what they observed and what the plans were before the battle. A common tactic was to fight in a line with the Admiral in the front. The stern of one ship would be close to the bow of the next making it easy to pass orders down the line. So the line of ships could maneuver and fight like one. If they had to quickly turn around there was a Rear Admiral at the rear of the line who could take over command and lead the line.",
"The main ship of the fleet where the person in charge of the fleet resides (today an admiral) is called the \"Flagship\" because ships communicated with literal flags. There would be a codebook with quick messages and an agreed set of quick signals to tell the fleet things like \"withdraw\". The Flagship needs a generalized plan, but for the most part ships are too slow to respond quickly especially when the brawls start happening so once the battle is going its a series of much smaller 1v1 and 1v2 engagements that go until they're done or the Flagship requests a withdrawal. Fleet battles were also relatively small, Trafalgar in 1805 was 73 ships in total. Every ship picked a target and pretty much just dueled that one. The Battle of Lepanto in 1571 is probably the fight with the most mid/large ships with about 400 galleys total but galleys are pretty small and only have like 2-8 cannons so there isn't much smoke and each ship has relatively limited combat capabilities so nothing changes abruptly Captains of ships end up with a lot of liberties in the actual tactical decisions because they are so isolated and so restricted in movement that its impractical to try to micromanage the battle, the ships can't effectively respond to commands in less than a few minutes."
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npbf41 | What is the gamey flavor we associate with non traditional meats like elk, bison, boar, etc? | Biology | explainlikeimfive | {
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"Mainly diet (i.e, no special feed mixes or specific grasses/pasturage to graze on), and more physical movement (less fat, more lean muscle) than a domesticated, farm-raised animal.",
"\"Meat\" isn't just muscle flesh from an animal. There is a very rapid aging process that occurs in meat shortly after an animal dies. Depending on the animal's health and stress level at the time it died, you end up with with one of three outcomes: 1) PSE meat, which is light colored and spongy 2) Normal meat, which is the stuff you find in your supermarket 3) DFD meat, which is dark, tough, and has the \"gamey\" taste people associate with non-traditional animals. The taste itself is the result of the meat being less acidic than normal meat. Animals killed on a large, commercial farm will be in good health and are killed instantly, so that the animal doesn't experience any stress while dying. This results in mostly normal meat being produced from their carcasses. There will be some PSE and DFD meat but it either gets turned into pet food or thrown out. When people go out and hunt meat they're killing animals that are typically in poor health and/or which are under a lot of stress (if for no other reason than that getting shot and slowly bleeding to death is stressful). This almost always produces DFD meat. Because people associate game animals with the gamey taste of DFD meat, some ranches that grow those animals commercially will deliberately produce DFD meat to maintain the gamey taste that people expect. But if you were to kill a game animal in the same manner as a domestic animal (IE, killing it instantaneously when at peak physical condition) then it would taste pretty similar to the meat from domestic animals.",
"It's a combination of everything you've heard below really. The meat itself is an animal's muscle mass. But that muscle is pretty flavourless by itself. The biggest contributor to its flavour is the animal's fat. That's why fatty cuts of meat tend to be much more flavorful than lean cuts of meat. A nice marbled piece of steak or a greasy slice of sausage or bacon has a much stronger flavour than a lean piece of chicken filet. And that fat derives its flavour from an animal's diet. Mass-produced meat often comes from animals that spend a lifetime eating the cheapest possible diets with little variety. You'll sometimes see stickers like grain-fed and grass-fed on supermarket beef, this has a minor impact on flavour. There are luxury meats where the animals are provided a much broader diet. Iberico pork comes from Spanish pigs that are raised in three different stages. In spring, they are fed fresh grass. During summer, they are fed the fresh harvest of grain. And in autumn, they're allowed to run free in the woods to eat acorns. They're raised for at least 6 months in this way before slaughter. Finally, fat distribution also makes a big difference. Animals that get plenty of exercises have much more fat interwoven in the muscle to make that marbled meat. Those Iberico pigs with their varied diets and plenty of exercise have a very distinct flavour profile to their meat. For wild animals, it's very similar. They eat very varied diets as they forage and they get lots of exercise. It adds a lot of flavour to the meat. Ultimately, there are other things that end up in the fat and thereby the meat as well. Things like hormones, medication and other pollutants. But those vary based on what you're eating and how it died so it's hard to account for them. At the end of the day, fat is the primary thing that gives meat flavour. And fat gets its flavour from diet and it's distribution in the body from exercise."
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