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mgx5dx | why are cold baths/showers so off-putting? | Economics | explainlikeimfive | {
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"It's shocking to suddenly have such a drastic change in temperature. But if you gradually make a shower colder and give yourself time to adjust, it's not so bad.",
"Water takes a lot of energy for it to change temperature. Contact with cold water quickly absorbs heat from your skin much faster than similar temperature air, thus quickly making you cold. That being said, I actually enjoy a quick, cold shower right before bed. Gets the grime off without removing the hydrating oils from your skin."
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mgxz75 | The reason for breathing in through your nose and out through your mouth | Biology | explainlikeimfive | {
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"The nose has mucus and air to filter out dust and bacteria. Also the nose's insides are a bit warmer and damper than the mouth so that the air is a bit easier to breathe in and to prevent pneumonia. Basically, nose boogers are just a ball of nasty stuff that would've gone through of you'd have breathed through your mouth.",
"Your nose is smaller than your mouth. To elaborate, your lungs need time to make use of oxygen. If you breathe in and out very fast, your lungs don’t do their job very well. Hyperventilating will make you pass out. Breathing IN through a tiny hole ensures that your lungs get time to get oxygen from the air you’re breathing. Breathing OUT might as well happen as fast as possible, so a larger exit is used. In through your nose goes slow, out through your mouth is fast. Doing it in reverse wouldn’t work as well. Also your nose moisturizes air, while your mouth would dry out from too much air.",
"breathing through the nose has several benefits: * allows you to use your mouth/teeth as a weapon while breathing * filters air impurities by passing it through nose's hair and mucous * warms cold air so it does not damages respiratory system. Breathing though the mouth has some benefits: * allows you a higher air intake. (have you seen 100m olimpiad runners? they breath exclusively through the mouth.) higher air intake = more oxygen = more burst energy. allows you to catch prey/run from predators better. * having a secondary breathing method allows you to breath when your nose is constipated due to a momentary illness.",
"Iirc the hair in your nose along with the mucous helps filter out some of the crap in the air. Secondary benefit is when breathing mindfully, it’s relaxing.",
"Ever since my omnipresent congestion has cleared (probably due to a diet change, but it’s hard to know with any confidence), I have enjoyed nose breathing mightily. I’m totally sold on that aspect of it. The part I wonder about is the mouth breathing exhale. Is it necessary? What benefits might it bring?"
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mgyaje | Why do people sometimes take deep, sharp inhales, instead of a typical breathe? | I sometimes notice my breathing goes into a sort of hibernation mode, gets very shallow and slow, almost to conserve energy? But then I have a deep, full inhale when I notice. What is happening here, and is the hibernation breathing dangerous? | Biology | explainlikeimfive | {
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"No answer here, but sometimes I just want to take that deep inhale but it just doesn't go all the way. I just don't get the refreshing feeling no matter how hard I try. Am I alone?"
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mgyv08 | Why does it seem like all animals like to be pet? | Biology | explainlikeimfive | {
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"They don't. Most animals would hate to be pet, they wouldn't even like you to get near them. But we tend to focus on animals that we get along with. That's why you see a lot more dogs and house cats than people keeping lethal box jellies as pets. It's mostly mammals that like to be pet as it triggers a stress-reducing response. And even then it's just the mammals that trust you enough to be near you.",
"For a lot of mammals, at least, it simulates grooming behavior. That's really what it boils down to. Grooming is always good. So is bonding. So good, in fact, that our distant ancestors evolved to produce a chemical that makes us want to groom (or really just touch each other tenderly) and bond. Social grooming tends to cause the body to release oxytocin (in both parties), which is basically emotional bonding in liquid (don't quote me on that, I've never seen hormones up close and personal) form. All mammals have it, and many other animals have something similar. It's the same thing that happens when you hold your baby or kiss someone you love or let your dog lick you. All the same chemical, just different methods of social bonding. Try an experiment. Have someone you love scratch your head (pointy fake nails are the best if you don't own a scalp spider) next time you're a little upset. Did it have a calming effect? Give you a sense of well-being? That's oxytocin in action right there."
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mgywer | Whats a Trace Route? | Technology | explainlikeimfive | {
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"Internet traffic is made up of sending packets of data from point A to point B. Part of that packet of data is \"number of hops\" which means how many things it can go through until an error happens. This is included to prevent packets being stuck in a loop forever. A trace route is a series of events to attempt to determine the path those packets take from A to B. You start by sending a packet that says \"I only want to go through a single piece of equipment otherwise return to sender\". That gives you the first step. You repeat this by increasing the number of allowed steps until a packet goes all the way from A to B and you build up a full sequence of steps. This entire sequence of steps is the \"trace route\"."
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mgyyz2 | Why can temperature only fall to absolute zero (273.15 C) and not any further? | I've always wondered how temperature can reach astronomically high values but somehow when it falls, it has a hard roadblock. | Physics | explainlikeimfive | {
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"We first need to start by saying that temperature is more than how \"hot\" or \"cold\" something is. Temperature is a measure of energy, and the movement of that energy. Cold objects have less of this energy, hot objects have more. This energy moves from hot - > cold, so what we think of as temperature is really describing the energy and which way it is moving. Absolute Zero is the point where that energy, the literal movement of the atoms in a thing, is at zero or close enough to zero to not be relevant. There is no where to go below that. You can't have something move a negative amount... because then it is moving... That's why it only theoretically exists and we haven't been able to create it. An object at Absolute Zero would literally be sucking heat from everything around it, so it's impossible to create the temperature. There is *always* something that is providing heat.",
"Because heat is a measure of energy. Theoretically, energy can continue to increase on into infinity. But there's a minimum of zero energy, and that's where absolute zero exists."
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mgz7g4 | Why do we never hear about heart cancer? | Biology | explainlikeimfive | {
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"They do occur but are very rare. Cancer occurs more often in cells that divide more often, the thing is unless damaged, the heart rarely undergoes cell division, hence lower chance for cancer [Neat picture]( URL_0 )",
"Your body is made up of little self-sustaining blobs called cells. When your body needs to repair damage, replace older cells, or just naturally develop these cells split apart and duplicate to create more cells. Cancer is when your cells for some reason start replicating for no reason and don't stop. The cells in your heart don't really duplicate themselves. Once you reach a young age your heart cells stop creating more cells. So heart cancer is very rare.",
"It’s very rare! Most statistics won’t even include it, because it’s so rare, the numbers are too low. But it still happens. Sometimes people mistake heart cancer for cardiac diseases. I think in some research regarding this topic they had 12.000 cancer patients, 0,1% had heart cancer, but from those 0,1% only 1/7 was heart cancer, the rest “just” were metastasis-formations"
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mgznpv | How come most things that get plugged into outlets (charging cables and appliances), the plug has a hole in each prong? | Technology | explainlikeimfive | {
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"These holes allow the wall socket to hold the plug more tightly by having small bumps that can slide part way into them. Think of the holes as little handles that the socket can use to hold onto the plug.",
"It was a standard. Manufacturers have to follow the standard. It's not needed now, but people are used to it so get weirded out by ones without holes. They are not meant for putting a lock through to make unusable. It was likely originally a way to let them stay in the socket better, but that function is no longer necessary nor designed into sockets.",
"If you're referring to a NEMA 5 outlet that's common in the US, then those holes are often used for locking the plug so it can't be put in an outlet or locking it from inside the outlet so it can't be removed. It's entirely optional.",
"This video ( URL_0 ) seems to indicate that it was either/both a mechanism for holding the plug in and/or a way to differentiate one design from another when one design was already parented."
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mgzntk | How do kids play the same or extremely similar children's rhyming games across wide regions? | I don't remember adults teaching me those rhymes that me and my neighborhood playmates know and when i was older and meeting other teens i found out they also knew those rhymes, so is that simply by word of mouth? If it is i mean that's an efficient children's information network. | Other | explainlikeimfive | {
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"It's kind of by word of mouth yeah, but it's not an information network. It relies on the fact that children of different ages interact with each other, so you get some overlap between play groups - if you have a group of 9 year olds with one 7 year old who all play a particular rhyming game, and then that 7 year old also plays with a group of 5 year olds and teaches them the rhyming game, you now have an entire new playgroup with the same game, which may also have a 3 year old in it who teaches it to their 3 year old friends. Playgroup overlap isn't just age-based either, it's also geographical. Just taking myself for an example, I lived on a street as a kid, and I went to a school. The kids on that street went to a total of four different schools iirc, so if I had brought a game to them from my school, they could spread it to three more schools from the neutral ground of my street. If someone from one of those schools liked it and brought it back to their street that's on the opposite side of town to my street, they could pass it onto kids who go to schools even further away. This happens because school catchment zones tend to overlap slightly (or in some cases quite significantly), as if the entire country were a giant Venn diagram. Then you also get a little bit of kids moving around as their parents do to top it off and allow some extra mixing between not directly adjacent catchment zones. You also see mutations in the rhymes over great distances, when the carrier of a new rhyme misremembers it or changes it to be funnier, and there's an element of shared media consumption nowadays too. Tom Scott did a [survey]( URL_0 ) a while back about the rhyme involving noisy metal and malodorous crime fighters that indicates younger people today know the egg-laying versions better than older people as a result of the simpsons, which broadcast the almost ubiquitous American version. For this to work the rhyme needed to be known first, but television replaced the rhyme for a lot of children for a generation or so."
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mh11nn | what is the concept of entropy? | Physics | explainlikeimfive | {
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"The universe wants to balance itself out evenly; that's the gist of entropy. Entropy is disorder and randomness spread evenly everywhere. You can create and build something, but given enough time it'll fall apart back into its core components. Take a cup of water; it has plenty of organization since the water is organized in a cup. If you spill the water, it disperses everywhere in a more even/random manner. If you have a hot spot in a room, the room will eventually even out in its heat. That's what entropy is. You may read that entropy is chaos, but that's not exactly true. It's just making everything even everywhere. You can reduce entropy in specific areas, but given enough time everything wants to eventually even out.",
"There are two approaches to entropy. I'm going to go with the statistical one. You have a bunch of red and blue marbles, neatly separated into either side of a bucket. You then shake the bucket a bunch, and the marbles mix together into a homogeneous mixture. No amount of shaking will reverse this process - this is an increase in entropy. Similarly, it I have a hot bucket of water and a cold bucket of water, mixing the two into a lukewarm bucket of water would be an increase in entropy, and once again would be irreversible on its own. The only way to reverse either of these is to do work - to increase entropy somewhere else even more than you decreased the entropy in your bucket. This seems very wishy washy, but entropy can actually often be measured. It is a governing principle in the motion (and use) of heat. It sets an upper bound on the efficiency of our engines, for instance."
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mh12b7 | Why is it that taking a few breaths of pure helium/nitrogen etc is enough to make you pass out or even kill you but you can hold your breath (inhaled or exhaled) and be perfectly fine for a minute or two? | Biology | explainlikeimfive | {
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"Oxygen moves from your blood because there is a higher concentration of it in the lungs than in the blood. Carbon dioxide will move from your blood to the air in your lungs because the concentration is higher in the blood. When you just hold your breath you still have oxygen in them and it can move to your blood and support you. But if there is no oxygen in the lunge the result is that oxygen that is already in your blood moves from it to the gas in your lungs. So the result is not like you add no oxygen but that you remove oxygen from the blood",
"To add to previous comments, your body has no mechanism for telling you it's low on oxygen. That overwhelming feeling to take a breath after holding your breath for too long is because of an over saturation of CO2 in your body, not because you're low on oxygen. This means if you're still taking breathes and exhaling CO2, but the inhales are something other than oxygen, you'll feel perfectly fine until you suddenly pass out and potentially get very sick or die."
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mh13hl | If artificial fruit flavors aren't made of real fruit, how do you mimic the fruit flavor? | It's bizarre to me that artificial strawberry flavor is as similar as it is to the real thing. Do companies just use chemicals similar to the ones found naturally in the actual fruit, or is it just many years of trial and error with random flavorings? | Chemistry | explainlikeimfive | {
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"They chemically break down what gives a fruit it's flavor and then synthesize and concentrate those chemicals into a solution. If you're looking for some demonstrations I recommend looking up \"nile red\" on youtube. He's demonstrated multiple chemical conversions of one non flavorful thing into an edible flavoring agent or perfume amongst other interesting chemistry demonstrations. For instance he takes plastic gloves and eventually ends up with the chemical for grape flavor in some sodas. URL_0",
"Specifically with artificial strawberry flavoring where they claim \"natural flavors\", that comes from beavers surprisingly. There are different chemicals that trigger similar responses to your taste buds and smell receptors as natural objects. Many artificial flavorings are from trial and error for creating chemicals and seeing what the smell or taste like. Sometimes it's intentional with creating a flavor/smell, but other times it's a side-effect of creating something else entirely. When they find a chemical that seems similar to something else, they'll test it to make sure it's safe. If it's safe, then they'll use it for an artificial flavor/color/smell. The reason different chemicals can create the same flavor/smell response to you is how it triggers the receptors. The different receptors require chemicals with specific endings that will interact with the receptors. The receptors don't care what the chemical is, just that it has an end that it can interact with. Natural and artificial flavors/smells are often different, but have similar endings that interact with your receptors the same and therefore smell/taste the same to you.",
"I don’t think that I’ve ever tasted anything that was flavored artificially that I actually felt was convincing. If it’s simply a matter of reconstructing the molecules, why can I always tell it’s fake?"
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mh1bw5 | Why do companies care about their Stock price after they IPOed , since they don't generate any revenue from the change in Stock price after that? | Economics | explainlikeimfive | {
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"Companies are owned by the shareholders. The shareholders want their investments to increase in value so they instruct the Board of Directors to hire a CEO that will keep the share prices high. If the Board doesn't do that the shareholders can vote to replace them, if the CEO doesn't do that the Board can replace them, if the employees the CEO manages don't do that the CEO can replace them.",
"Don't think of the company as a separate entity that has goals. The company is owned by its shareholders, so if the shareholders want to see the value of their equity go up (which typically they do) then they will instruct their staff to act in a way that achieves company value growth.",
"They don't sell all the shares. The company often hold on to a good portion of the shares. This allows the company via the board to maintain control, and also derives a passive income based on stock performance. A big portion of executives bonuses, if not pay, is often linked to stock options. So they care about stock price. People who started up the company or got in early are almost certainly holding stock, who's value can surge during a successful IPO, then continue to grow."
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mh25nd | If I have a super large telescope, would I be looking towards the beginning of the universe no matter which direction I point it? | I read that the Hubble telescope could look 13.2 billion years back in time - what would it see if it turned 180 degrees and looked the other way? | Other | explainlikeimfive | {
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"Everybody is the center of the universe due to how it expands universally. If I were in another galaxy looking somewhere, what I saw would show me as in the center of the universe and what you saw here would show you as in the center of the universe. There's a fixed limit to what can be seen by any telescope so if the Hubble points in one direction it'll see a certain amount of time into the past and if it points in the exact opposite it'll see the same amount of time in the past. There is a caveat though due to things like gravitational lensing. If you find such a lens effect, then you can see further away than you normally could and therefore further into the past. This requires a very specific alignment of galaxies and dark matter between you and the object on the other side of it. If you're referring to this effect as the limit, then the time you can see into the past differs based on how strong the effect is and where it's located. Different lensing effects magnify what's behind them differently so you aren't guaranteed to see the same timeframe into the past with every lensing event found.",
"'Back in time' is not in a physical direction. The Hubble telescope can see things as they were many years ago, because that light has taken a long time to reach us. It would be like if your friend went to a distant city and took a photo and then brought it back to you two weeks later. The city in the photo is how it looked two weeks ago, not how it looks right now.",
"Because light does not travel instantaneously and has a speed limit (C), no matter which direction you point your telescope, it will always view objects as they were in the past. And the further away you look, the further into the past you are looking. For instance, when you view the moon at night, you are actually viewing the moon as it was approximately 1.3 seconds in the past. When we view mars through our telescopes or if you spot it in the night sky, we are seeing as it was between a 3-13 minutes in the past, depending on the relative orbits of Earth and Mars. And when viewing the closest star (Proxima Centauri) to our solar system, we are viewing it as it was more than 4 years in the past. So, you can extrapolate from there, and see, that if you continue to move further away in your observations, you will continuously peer further into the past, irrespective of the direction you are looking. In fact, if the sun spontaneously exploded or extinguished itself, we wouldn't even know it happened until 8 minutes after the fact. We would simply look up and see the sun, without noticing any difference whatsoever. Kind of fun. ELI15: In fact, the latest measurements of the curvature of the universe suggest it is flat (and infinite) and there is no preferential point from which the universe expands. This means the observable universe from earth, the entire universe from our perspective (90+ billion light years diameter, due to inflation), is just one in a likely infinite set of observable universes, all of which, aside from our own, we will never be able to access. And even within our own observable universe, assuming we could travel at light speed, we would still only be able to visit approximately 6% of what we can observe, due to how fast everything is moving away from us.",
"So here is something that needs to be explained so that you kind of get a better picture of what’s going on. When you use a telescope and look “back in time”, it’s not really looking back in time as people would think. Saying you’re checking out a star 5 billion light years away. What you see in the telescope the light given off is 5 billion years old, as that’s the time it took the light to travel to you. That’s why they say you are looking back 5 billion years. Something like the Hubble telescope has the ability to look further than your standard telescope. The further you can look the further these objects are away which means the light takes longer to reach you. There is no need to do a 180 degree turn to see the other way. The telescope orbits the earth going round and round, and it’s always pointing outwards. So it’s constantly working to give us a 360 degree view. Think of it like putting a camcorder on a lazy Susan and then spinning it. You’ll get a view of the room 360 degrees on the axis of the lazy Susan. So turning the Hubble the other way would pretty much just show us pictures of earth honestly lol. As far as whats out there? Basically the universe is expanding at a rapid speed. So it’s not like we will ever be able to see the edge of the universe. So whatever we see through the telescope is the light being shot at us from that direction. We have no way of seeing what is past the edge of the universe.",
"No matter which way you look, you will be looking into the past. Everything you see in front of you, you see as it was at some point in the past. It takes time for the light from any object to reach your eye. Say you're looking at a computer monitor 24 inches in front of you. (using mine as a measure).: The speed of light is \\~186,000 miles per second. So it took the light from your monitor \\~2 nanoseconds (2 billionths of a second) to reach your eye. You're seeing it as it was 2 nanoseconds ago. You see the moon as it was 1.3 seconds ago. You see the Sun as it was over 8 minutes ago. It could have exploded 4 minutes ago and we will not know it for another 4 minutes. The further distant an object is, the older the light reaching your eyes from it.",
"Yes. You would be. However, you will not be able to see it because of doppler effect. As universe has been expanding at very fast rate, the light that was emitted during big bang has also stretched out. The stretching of light means increasing wavelength in the micrometer range. So the light would be a Microwave. Since at the beginning the universe was completely concentrated at a single location with very high density, and it expanded in all directions, we see uniform image across all directions. Sine the waves will be MICROWAVE, distributed uniformly EVERYWHERE throught the COSMOS it is called Cosmic Microwave Background (CMB). So besides being large, the telescope will also need to be able to detect microwaves."
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mh355u | Why do streaming services owned by studios have to pay their parent companies for their own content? | It's like how Peacock paid NBCUniversal $500M for The Office, even though Peacock is owned by NBCUniversal. Or how HBO Max paid Warner Bros $425M for Friends, even though HBO Max is owned by Warner Bros. If a studio owns a streaming service, how exactly is that streaming service paying that studio for the content? Is the studio just paying itself? How exactly does that work and why do they have to do it? | Other | explainlikeimfive | {
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"It is complicated. TV shows and movies have things like syndication rights and some of the actors are due payments from selling these rights. Friends, for example, is a series where the main actors have contracts stipulating that they get some percentage of the payment received by the studio selling these rights. So there would definitely be major legal proceedings brought by the actors if HBO Max didn't pay Warner Bros. The actors would definitely claim that Warner is trying to avoid paying them their cut. These kind of contracts are very common (actors, directors, screenwriters especially famous ones negotiate them). So firms try to have \"arms length\" contracts even between related entities. Even within a big company, there are divisions and typically each division is held to their own financial goals. The head of one division is not likely to subsidize the operations of another division. There are issues of taxes. Especially when it comes to subsidiaries that have operations in multiple geographies. Although a parent company may elect to file a single tax return, this isn't necessarily tax efficient. A company wants to report profits separately especially if taxes in foreign jurisdictions are lower than domestic ones. This gets complicated very quickly. Then there is long term strategy - the parent company might want to spin off subsidiaries in the future. This could be to have a separate IPO or to bring in money from a separate investor. In that case, keeping relatively separate accounts helps tremendously.",
"Imagine this scenario. I make a tv series and I'm owed syndication royalties for whenever it's broadcast. Somebody needs to pay me to show the series and it doesn't matter who the companies are. On a high level it may appear that NBCUniversal is paying itself, but the money is going from company A to company B so the people who are owed money by company B selling the rights can be paid. Also, many companies will operate independently and just happen to be owned by a parent company. They still have to operate like any other company and send/receive money where it's applicable. If I own two companies, for tax purposes at the very least I must show a transfer of money from one company to the other despite owning both entities.",
"Basically, it's important for legal and accounting purposes that the money be transferred between the subsidiary companies.",
"Yes at the \"studio\" level it is likely just paper money getting moved around. But there are checks getting cut down below. Basically why boils down to office politics. While you're correct to say that NBC Universal is buying The Office from itself, in the office politics it is better to say the VP of NBC Streaming is buying The Office from VP of NBC Entertainment, producers of The Office, and anyone else with residuals. (Who exactly signs is unimportant). Yes this is encouraged by the bosses above the VPs but the $$ assigned to VPs are important. So VP of NBC Entertainment has targets and bonuses. He makes money when he sells his shows. He would like to sell to Netflix/Amazon for $$$. So his bosses say we will give you sales dollars for playing nice with VP of NBC Streaming. Likewise the producers / residual holders get paid when shows re-sell. They would complain quite a bit with lawyers and such if the payments from The Office went from a lot to zero. So again a \"sales\" price is documented and used to payout 3rd parties."
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mh3pac | Spiders can crawl up walls into high spaces, why can't they climb out of the bath? | Physics | explainlikeimfive | {
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"They can, given enough time, but bathtubs are designed to be smoother and are consistently more wet than even the walls of a shower. That makes it harder for a spider to get up out of the tub, especially before the humans in the home come in and flood the tub with water",
"Imagine you're wearing socks in your house and you slip over. If you're on a smooth, tiled floor you don't have any grip and will fall over. If you're in a carpeted room, you'll have better grip. This grip between your socks and the carpet is called 'friction'. Although walls seem pretty smooth, they are still a slightly rough surface in comparison to the inside of your bath. The spiders feet won't have any grip and therefore the spider will find it harder to climb out. This is because there is no friction between the spiders legs and the bathtub.",
"Because spiders have some little hooks at the end of their legs. The hooks are what make possibile to climb but this depends from the material. On the bath the hooks have nothing to clinch.",
"Friction. Spiders can go up walls because they're not completely smooth like bathtubs. It's like walking on a normal sidewalk compared to walking on an iced over sidewalk. Uphill."
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mh3rzl | why are you considered a homeowner when you still have a mortgage? | Other | explainlikeimfive | {
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"If you have a mortgage you still own 100% of your home, the only difference is that the lender has the right to take it off you to recover your debt. Consider that if the home goes up in value you get 100% of the gain, if ownership was split then so would the capital gains.",
"A mortgage is a loan. You own the home, and you also have a loan to pay. It's like buying a phone with a credit card; you own the phone immediately, and the fact that you have credit card debt is not related to your ownership of the phone.",
"I'm a homeowner and I have a mortgage. I can decide to do whatever I want to my house because I own it. I built a new door in the house and I repainted a room. I removed some phone ports and a grill vent. When property taxes are due, I have to pay it. When the house goes up in value, those gains are mine. Really I make all the decisions and do all the same things as someone who has paid off their mortgage. The only difference is that I owe money to a bank. That doesn't mean I don't own the house. It just means that if I don't pay, I might have to give up my house. In that case, I still owned it until the bank took it from me.",
"Because you are. The fact that someone else has lend you money to buy it, does not change that. You own the house and you owe money to the lender.",
"So a lot of the answers here are stating that just because you have a loan doesn't mean you don't own the house. And that's true. But as a first-time homeowner, this was super confusing to me, too. I don't own my car until I pay it off. And I don't get the title to the car until I pay it off. But when you buy a house, you get the title deed. The mortgage loan is like a special case of an unsecured loan, insofar as the lender has no ownership stake in the property being purchased. Contrast that to a vehicle loan, where the lender is the second \"owner\" listed on the title until you pay it off and can apply for a title in just your name."
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mh426z | How does Curvature Speed works? Doesn't it break what we thought was a law of physic? | So there was a huge article months ago where some crazy scientists proved theoretically that a spaceship can reach curvature speed (travel Faster than light) There was a post here days ago that said that speed is relative and you can't go further than light because it is the only non relative speed (the example was if you stay on a train that goes 9.8c and shoot a bullet that goes 9.8c you can't exceed C ). So why would their curvature speed work? Also, side question, wouldn't they have to worry about asteroids getting in the way when traveling faster than what they can see? Also, another question, Would travel faster than light make them go back in time? Since If i remember correctly time depends on light or something, wouldn't go faster than it transform you in The Flash and make you go back in time, Technically letting you arrive before you started traveling? | Physics | explainlikeimfive | {
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"FTL travel through space is not possible. Full stop, no \"but maybe\"s, no \"that's just closed minded\" no other nonsense like that. Nobody proved anything. ~~I've seen the paper, it's about as theoretically accurate as the starship Enterprise.~~ it turns out this is a different paper. It still doesn't prove anything, but there is a possible theoretical framework for the warp drives suggested if you make some unverified assumptions. There is no telling what would happen if something did go faster than light, because it breaks our universe. It's like asking \"Okay, but if 3 > 4, what would happen?\" I don't know, it's impossible to tell."
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mh4987 | How do lungs get stronger? | So I’m a runner and one of the road blocks that pops up from time to time is that my legs feel fine, but my lungs just can’t keep up with the speed. I’ve noticed after a hard run, I get a sort of cough and a bit of mucous build up like I’ve damaged my lungs in a way. Is this the same process as other muscles? Create little micro tears in muscle, body sends nutrients to site of damage, tears recover, muscle gets bigger and stronger. Or is there something else at play that makes our lungs stronger over time? | Biology | explainlikeimfive | {
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"It sounds like you may have [exercise induced asthma]( URL_0 ). This doesn't mean you'll have a full all asthmatic attack. Your lungs may feel like they're chafed. I have to use an inhaler before I work out to keep it from happening. Talk to your doctor about it.",
"The lungs themselves are only part of the puzzle. The purpose of lungs is to bring oxygen to your blood. So if your blood and heart gets better at carrying oxygen in larger amounts and more efficiently your lungs wont have to work as hard. Exercise have shown to change many things about your blood such as plasma amount and number of red blood cells.",
"Since others covered your question I will just add that according to recent studies, it's not the micro tears that happen during exercising that make muscles bigger and stronger (hypertrophy), but the metabolic stress introduced during a workout.",
"> I get a sort of cough and a bit of mucous build up like I’ve damaged my lungs in a way Do you also have a metallic taste in your mouth? coughing up a bit of mucous doesn't mean you damaged your lungs by excercise. But points to allergy, a cold or infection etc",
"Coughing and mucus are not, in themselves, a bad thing. Aerosolized metabolic waste comes out of our lungs with every exhale. Also environmental toxins can enter our lungs. When you breathe deeply and exercise, this stimulates the lungs to throw off waste. That's what mucus is for. It's the bodyguard that escorts the waste out, hopefully without damage. Its a good sign. Ideally you want to see thicker darker blobs of mucus surrounded in lots of runny clear mucous. Think of it as a bonus inner shower. Your lungs will get stronger as they are detoxified. If possible, don't wear a mask while exercising. Your lungs get stronger by being challenged and having the nutrients to respond. Micro-tears can happen in the lungs but are not helpful in this case. Mostly they happen from dry air forcing through dry tissues, causing abrasion on delicate tracheal tissue. Stay hydrated, take electrolytes and your ACES. Try to bring up any mucus gently. Most important: practice deep breathing exercises such as yogic breath or wim hof breathing. The lungs will benefit from the growth of blood vessels throughout the lungs. Tiny blood vessels around each alveoli are stimulated by exercise that puts you into a temporary oxygen debt. So push yourself hard aerobically for at least 20 secs 3× per workout. Ie: go hard until you're gasping for breath, just for a short time, about 3 times per workout. Human growth hormone will enhance the growth of the lungs. Your body makes hgh in response to exercise, sleep, relaxation, fasting, meditation and play. Stay away from stress triggers on your lungs until they get stronger( cold air, high histamine food, pollution). Get an inhaler if you can't seem to avoid it. There are plants that can help strengthen lungs Unexpressed grief can be held in the lungs. I hope this helps!"
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mh4r8a | Why women voices sound more comforting than men voices? | Biology | explainlikeimfive | {
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"Maybe a subconscious connection to a mother's voice. Although I'm sure some people find men's voices more comforting as well",
"It probably comes from the womb and childhood. You'll hear your mother's voice before anything else and probably just associate it with safety and comfort. Also, men's voices are just deeper and louder. With most animals, loud and deeper noises are associated more with danger because they usually belong to bigger, more dangerous animals."
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mh5bra | Why aren’t windows that are 64” a standard window size?? | Other | explainlikeimfive | {
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"One of the reasons is how windows are made. You don't just manufacture a single pane of glass for each and every window. Instead, you manufacture a *large* piece of glass, and then cut it up into different sized windows. The way that this large piece can be broken down dictates what standard sizes are. Any deviation from that results in loss from the batch, which comes with a premium cost."
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mh5hqp | Why isn't iron pulled down to the Earth? Would magnetic materials like iron be lighter or a planet without a magnetic field? | Physics | explainlikeimfive | {
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"Earth’s magnetic field isn’t powerful enough to actually move anything with much mass. That said, iron is denser than rock and it is pulled down into the earth by gravity. When the earth was forming and still completely molten nearly all the metal *did* sink to the center. Metal deposits we find closer to the surface were deposited later by asteroid impacts or volcanic activity.",
"Well, to begin, it's worth mentioning that Earth's magnetic field is extremely weak, so any force it applies would also be very weak. Next, iron isn't magnetic on its own. It has to be magnetized. In natural iron, this can be done by Earth's magnetic field, but that resulting magnetization is also extremely weak. Now, we can think about what forces the iron experiences. Think about it this way, if you're looking at a compass, does either end of the needle get pulled down? It doesn't. Instead, it aligns itself with the magnetic field. That's because magnetic fields are shaped differently than other force fields (Google \"magnetic field lines\" to see the shape). They don't just push or pull from the center, they have two poles and the field lines curve out between these poles. When iron is magnetized in the crust, it's already aligned to the magnetic field because that's what magnetized it. It is then pulled slightly harder toward the pole it's closer to, but not so much that it really affects anything. Earth's gravity is far, far stronger than its magnetic field. In summary, Earth's magnetic field wouldn't pull the iron down so much as toward the closer magnetic pole. However, this force is very, very weak compared to Earth's gravity so it has no effect."
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mh5wk6 | Day time vs night time vision | I learned that felines have (around) 6 times better night vision than us humans. It’s hard for me to get a reference as to how good that is. I thought a good starting place is: How many times better can humans see in the daytime vs the nighttime? | Biology | explainlikeimfive | {
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"That's a difficult question to put a number on I think because day time and night time vision work in different ways. During the day, lots of light enters your eyes. Humans have lots of cones in eye the which makes us extremely good at distinguishing different colours. Cats have fewer cones so aren't as good at seeing during the day as humans are. At night time when there's much less light, you need rods to be able to see. Rods don't distinguish between different colours. The reason cats can see much better at night is first, that they have way more rods then we do and secondly, their eyes have evolved to capture more light when there isn't as much around. You can measure these two things and come up with a number like 6. So if cats have 3 times as many rods and their eyes capture twice as much light, you could say their eyesight is 6 times better. You can't really do that when comparing day and night vision because they work differently. During the day, we use rods and cones to see so it's difficult to put a number on. If you want to imagine the difference between human and cat night vision. It'd basically be like watching a black and white movie in really low contrast and really low brightness. A cat would be turning the contrast up by 2 or 3 times and the brightness up by 2 or 3 times."
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mh6d6c | what is wifi ? | Technology | explainlikeimfive | {
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"Wifi is a wireless version of a network cable. Many people will assume it has to mean internet but that's not necessarily the case. Wifi is used in Amazon warehouses by the hand-held scanners people use to scan boxes and items. But that wifi on those scanners does not give them the normal internet. The way Wifi works: a device called a Wireless Access Point (which is sometimes included as part of a modem/router device) has antennas that send out (and receive) radio waves. These Wifi radio waves have specific radio frequencies, and it's those specific frequencies that dictate that it's Wifi and not something else. Certain frequencies can be the radio in your car, other frequencies are for cell phone data/voice service, other frequencies can be GPS navigation, and believe it or not, other frequencies are actually visible light... and so much more. URL_0 But back to wifi. So the antennas that put out waves, send them out into the air. People need wifi-capable devices to look into the invisible part of the radio spectrum that includes wifi, and find the signal. Then we can log in to the wifi network and connect to whatever the Access Point is broadcasting. It could be internet or any other network, even a person to person network including only two people. There's so much more I could say but this is already above a five year old's head probably and it gets worse from here.",
"In a word: light. WiFi is a brand name, it doesn't mean anything. WiFi describes a wireless standard that any manufacturer can implement to facilitate computer networking over *radio*. So a bit of background: microwave ovens. Some guy in the 1940s was working on RADAR for the military when he noticed a chocolate bar in the lab had melted. A quick investigation later, he found the radio waves emitted by the RADAR equipment excited water molecules in the food, heating it. The microwave oven was born shortly after. Microwave ovens are noisy devices on the radio spectrum. Manufacturers try to get by with as little shielding as possible to save on manufacturing costs. This became a big problem when practically every household in the nation got a microwave oven. Luckily, water is excited by very specific radio frequencies, so all microwaves make the same RF noise at the same frequencies. The FCC then allocated the 2.4 GHz ISM band, a range of radio frequencies where microwaves make their noise. The noise renders these frequencies effectively useless for commercial purposes as they're quite unreliable and full of noise. Therefore, they're left basically unregulated. The FCC is the commission in charge of, among other things, policing and regulating the use of radio frequencies in the US. They set the rules. And they say anyone can use these frequencies for *almost* any purpose, but they have to be tolerant of noise and other competing transmissions. So manufacturers LOVE the ISM bands, because they can make wireless products and not have to pay a dime for licensing. So there's a whole slew of baby monitors, cordless phones (are you old enough to remember those?), remote controls, and other gadgets that use these frequencies. Enter the late 90s and the boom of the internet. Naturally, someone was going to do this. We already have Ethernet, a standard of communication, and some of that standard explains how to communicate over coaxial cable and twisted pair, the 802.11 section of the standard goes on to explain how to generate the appropriate radio signals. Here's the thing about the electromagnetic spectrum: *there's only one*. There's only one 2.4 GHz ISM band that is 220 MHz wide. And to operate unregulated, your devices can only transmit using a maximum of 1 watt (which is more capable than you think). Your WiFi router is a lightbulb, the antenna is the element, and the light is invisible to your eye. At 1 watt, it's dim, but almost everything *solid* is opaque to it - this light literally shines through your house and your body with little attenuation. But not only is your router shining light, so is your laptop, your tablet, your phone, literally every WiFi (AND BLUETOOTH!) enabled device is shining light in this band. Every device that is in range of the emitting antenna is getting shined upon, and their antennas are receiving those signals. Every network is divided by an SSID - if you're not \"connected\" to that network, you still get all that traffic over the radio waves, your device just ignores it. Every message to or from one device to another, every device in range is getting rained upon with radio signals they're dutifully ignoring if it's not marked for them. This means the more devices in range, more specifically the more *active* devices all in range, the slower everyone has to go, because only one device can transmit at a time. It's like if you closed your eyes and turned on the overhead light and a desk lamp. Which light is from which source? All you see through your eyelids is light. So it doesn't matter how strong your signal strength is, if everyone is streaming Netflix, everyone is going to have a bad time. This is why you should spare your bandwidth and physically cable in every device you can. Have a desktop computer? Run a cable to the router, don't use a WiFi card. This makes laptop docking stations appealing again. Finally, there's a bunch of revisions to the standard, and they're all lettered. 802.11 is part of the standard document that describes WiFi, but there's 802.11a, 802.11b, 802.11ab, 802.11g, 802.11n... The list goes on quite a bit. They all use more and more bandwidth, even using *additional* ISM bands at 5 and 6 GHz, but at those frequencies, the light has trouble shining through paper, and they're really meant for line-of-sight across the room from the router to a media center. If someone walks in between, the signal drops. Just run a cable!"
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mh6lbp | why do a lot of small YouTubers get shut down for having 10 seconds of a song while some are fully based on playing parts of movies | Other | explainlikeimfive | {
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"You are referencing 2 completely different mediums with completely different copyright rules. Clips of movies can be used under \"fair use\" if its transformative in nature. Meaning the content you are creating must be different than the content of the movie itself. To give an example, a review or an analysis of a movie is considered transformative and therefore fair use because you aren't reproducing the movie or simply presenting the whole movie, you are making a review or an analysis video which just happens to be improved by the use of select movie clips. Music must be licensed if it is included in your video because its seen as adding value or enhancing what you are making. Generally speaking you are allowed to play small clips of audio for review or reference purposes and people do this all the time however because of the widespread misuse of music in videos the recording companies are fairly aggressive when making claims against use of their music which results in platforms making blanket 0 usage policies (twitch and to a lesser extent youtube for example).",
"Some have licenses to use the music, some have permission to use clips, some use it under 'fair usage' policy and some get copyright strike but are allowed to leave the video as long as it's not monetized, but the copyright holder will add monetization to the clip in their video.",
"Youtube uses automated systems to detect copyright infringement. Pirates take steps to defeat those systems. Cheap youtube bootlegs are usually altered. I've noticed a variety of techniques, including speeding it up, slowing it down, reframing shots, or just turning the quality down to \"barely recognizable\" For example, this pirated bootleg upload of Futurama reframes the shot every few seconds. When youtube runs their algorithm, it's fooled, and it remains online. [ URL_0 ]( URL_0 )"
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mh77ic | What do scientists mean when they say that light is an electro magnetic wave? | I've seen one multiple educational videos that draw light as two orthogonal waves traversing through space. What is that trying to represent?What exactly is going up and down? Furthermore, why do people often make the analogy that light acts like a ripple in a pond? | Physics | explainlikeimfive | {
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"There is an electromagnetic quantum field (EMQF) permeating all of space. Electric fields and magnetic fields are classical representations of interactions involving this EMQF. Light is a fluctuation in this EMQF, and this representation explains the photoelectric effect (which isn't explained in classical electromagnetism). If you think of a flash of lightning, it's a lot like a rock tossed into a still pond. This large electric current agitates the gas atoms in the atmosphere, and when they relax they release light in all directions, like how the rock sends waves in all directions on the pond. The surface of the pond is 2D, and the EMQF is 3D, but otherwise it's similar."
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mh7xud | How do Sex Addicts Anonymous Meetings work to avoid people from having sex with eachother? | I know sexual relations are considered not allowed for ANY XA type meeting but with sex addicts people ARE the drug. So it strikes me as really difficult to have a meeting without it being dangerous for relapses. | Other | explainlikeimfive | {
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"These meetings are there to empower you because you want to change. Nothing is stopping an alcoholic from having a drink before a meeting, although they may be asked to leave if they’re influencing other members who wouldn’t do so otherwise. They’re not there to force change on you. Addiction of any kind can only change if the person has reached a point they have the conviction to make that change. They offer support and advice, not rules and punishment.",
"When you're going to an SAA meeting, you are trying to deal with a problem that's negatively impacting your life. If you were just looking for someone to have sex with, you'd be at a bar. The point of the SAA meetings is to work through removing this negative impact. If you like sex and having it doesn't negatively impact you life, then you don't want what SAA offers."
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mh83qk | Why does the Newton-Raphson method work? | I'm creating a program for finding the square root of a number, and I came across the Newton-Raphson method, an algorithm that solves my task. I only saw the pseudocode for the algorithm, but I never really understood why it worked. Can someone explain to me why it works without all the heavy math? | Mathematics | explainlikeimfive | {
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"There is a [neat animation on the Wikipedia page]( URL_0 ) which gives an idea of how this works. Essentially you are pretending that your function is a straight line, not a curve, and then finding where the 0 would be. You then assume that your new point is closer than your earlier one and try again - finding the new line (tangent to the curve at this point) and finding where that crosses the x-axis. And you repeat. It doesn't always work, but when it does, it tends to work fairly quickly.",
"Let's say we're looking for X, and we have A that is smaller then X and B that's bigger then X. In which case A+B / 2 will be a good approximation of X (even though A, or B can be closer to X in certain cases). Think middle of the road, of which A and B are boundaries. Now in case of a square root: 1. Assume N = sqrt(M). We don't know what N is. 2. Let's say X0 is our best guess as what N is. It can be either bigger then N or smaller. But at the same time A / X0 will be either smaller, or bigger then N. 3. That means that N is between X0 and M/X0. We can use the fact above and say A = N and B = M/X0 4. So X1 = (X0 + N/X0) / 2 5. Repeat 2-4 enough time, that you get close enough :) Example. We're looking for root of 10 1. A = 5 B = 10/5 = 2 X1 = (2 + 5) / 2 = 2.5 2. A = 2.5 B = 10 / 2.5 = 4 X2 = (2.5 + 4) / 2 = 3.25 3. A = 3.25 B = 10 / 3.25 \\~= 3.07 X3 = (3.25 + 3.07) / 2 = 3.16 As you can see after 3 steps by narrowing down the left and right side we're reached the result with 2 significant digits which is 3.16. What's important is always choosing a correct functions so that outcome always lies between A and B."
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mh9ejh | why does the moon appear larger earlier in the night, when it’s “rising” as opposed to later in the night when it’s higher in the sky? | Earth Science | explainlikeimfive | {
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"text": [
"We think its because near the horizon you have known objects to compare its size to. Its easily testable that it is just an optical illusion and no size change is happening, hold a coin at arms length and it will cover the moon both near the horizon and at the zenith by the same amount.",
"Your perspective. When the moon is closer to the horizon you have things like trees, houses, water towers, etc. to \"compare\" it to. When it's higher in the sky there's nothing to compare it to. If you could measure the width of the moon at the horizon (where it appears bigger) and then measure the width when it was higher in the sky, you'd find that the measurements are the same. ELI5 = It's an optical illusion."
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mh9er1 | What is the typing noises in the middle and at the end of robo calls? | For example, if you call hr block, you get a robot, after telling her where you want to go verbally, you hear typing noises. | Technology | explainlikeimfive | {
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"It's a \"spinning circle gif\" for your ears -- people are accustomed to hearing someone on the other end of the phone typing while not speaking, so they wait for a response. It's for a \"there will be a short wait\", versus being \"put on hold\" which means \"I have to wait a while\". It's a trick to make you keep listening, or make sure you don't think you've been disconnected.",
"It is a recording to try to make old people trust the robocall. People don’t like change. Think of it like a security blanket."
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mh9g3h | What causes an undertow? | Physics | explainlikeimfive | {
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"Water is constantly moving in most directions. When a wave washes ashore before being dragged back to waters edge you see this at work. Undertow is essentially the same thing on a bigger scale, the water on top is coming towards the coast and the water underneath is going out."
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mh9hd2 | | Why do some places get massive tides while others don't? | Not exactly ELI5 but a better perspective . [Tides]( URL_0 ) | Earth Science | explainlikeimfive | {
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"Geography While the location of the moon changes the height of the tidal bulge, that doesn't actually resolve why some places have stupid large tides. The Bay of Fundy in Nova Scotia has a 13 meter tidal range while the global average is just 1 meter The really big tidal ranges come from geography and geometry forming a resonance for the tides. If you've got an opening just the right width and shape you can stack the waves from the incoming tide to create really low tides and really high tides that make rivers flow backwards. Generally this is seen in relatively wide ( > 100 km) bays that are fairly long and can funnel the tides in",
"Latitude and elevation change. The tidal bulge is largest under the moon (almost directly, it tails a little behind). The further away from the current latitude of the moons orbit you are the less mass(height) of the tidal bulge. Elevation change is the second reason. If the tide is rising by 5 feet, but the slope of the ground rises that five feet over a distance of 20 feet, you only see the tide come in 20 feet. If the ground rises 5 feet over a distance of 200 feet, you will see water rushing in to fill the larger area."
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mh9n96 | Atmospheric Convection | Earth Science | explainlikeimfive | {
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"Sun heats up the Earth, the Earth heats up the air, the hot air close to the ground rises and cool air comes down to take its place where it is heated back up and rises to continue the cycle."
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mh9tco | Why do our bodies/ every living things body need water to survive? | I understand that we need for to survive since we break down the nutrients inside for energy, but the use of water confuses me | Biology | explainlikeimfive | {
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"Virtually all the chemical reactions in our bodies happen \"in solution\"...the chemicals are dissolved, or at least free floating, in a fluid. For humans (and all other forms of life we know about), that fluid is water. Water is what lets the molecules that \"make us go\" move around and interact with each other. Without water we're a pile of non-reacting chemicals. Try baking a cake without the wet ingredients and you kind of get the idea. We lose water to our environment constantly, since we're way wetter than our surroundings and we use some of it to carry waste out of our bodies, so we have to keep replacing it or we shut down and die.",
"Chemical reactions take place easily in the medium of water or using water, with the amount of water on Earth it meant that the life we know have adapted to use those reactions to live, without water being present it is possible that life may have found other ways to exist."
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mhaax8 | Why do we brine meat? Due to osmosis, water moves from the less salty to saltier solution to balance out salinity (eg, shriveled fingers in a pool); articles claim that while brining, the salty solution actually enters meat. If true, why does the movement of saline solution work in reverse? | Chemistry | explainlikeimfive | {
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"> Due to osmosis, water moves from the less salty to saltier solution to balance out salinity **(eg, shriveled fingers in a pool)** That’s not why we prune in water. > Pruney fingers and toes are actually caused when blood vessels just below the skin shrink — a process called vasoconstriction. When your nervous system is functioning properly, soaking in water sends a message through the nerves telling those blood vessels to shrink. The loss of blood volume makes the arteries, veins and capillaries skinnier. Then the skin over them collapses into wrinkles. URL_0",
"Two things, first, the shriveled fingers in the pool doesn’t actually come from water entering your body and is actually a reaction caused by your nervous system. Where the presence of water causes a message to be sent telling blood vessels to shrink. So yes the water is the initial trigger, but what actually causes the shrivels in your blood vessels constricting. But to answer your real question. Osmosis is just diffusion but specific to water. When in a solution anything will diffuse. Like when you put food coloring in a glass of water it spreads out through the glass. If you then put a piece of meat in that water with the food coloring, you’d expect some of that coloring to end up in/on the meat Right? Well the same thing works for salt, just like food coloring moves from areas of high concentration to low concentration (diffusion). Salt will move from areas of high concentration to areas of low concentration. And brine is SUPER HIGH in salt, like close to being saturated with salt. So the meat will have a lower concentration than the brine does, and diffusion will take place.",
"I believe it’s because the salt concentration in the solution is greater then the salt within the meat as is the water content in the solution, it is higher then the water content of the meat. Hence both enter the meat in unequal amounts but overall the meat gets saltier and wetter or “brined” as they call it."
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mhao1v | - How would a scammer get a phone number? I’m getting spoofed calls from scammers, and it’s throwing me off, but one number that I received a call from isn’t associated with me at all yet. | Technology | explainlikeimfive | {
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"I believe it depends on where you live but that phone numbers are listed publicly and it was fairly recently that cell phone numbers also got listed... I may be wrong tho I don't actually have factual information to present"
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mhapx0 | What are the layers of the earth and what purpose do each of them specifically serve? | Earth Science | explainlikeimfive | {
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"Why are you under the impression that they serve a purpose?",
"Crust- crispy outer shell that you can stand on. Useful for growing trees, holding the oceans, and preventing your legs from being burnt off by the mantle. Mantle- hot liquid bit. Earth's gooey centre. Useful for holding up the crust, and for making volcanoes. Acts as the source of geothermal power, and keeps the tectonic plates moving, which allow the map making industry to make a killing every few million years by making the old charts outdated. Core- hot solid bit. A crystal of iron under enormous pressure, the core acts as the magnetic lodestone around which our geomagnetic field is strung. Helps hold up the mantle, and indirectly permits compasses to work.",
"Most models divide the planet into the core, mantle, and crust. The core may sometimes be separated into inner and outer, with the inner being basically a ball of solid metal and the outer being liquid metal. The core is believed to be responsible for generating the electromagnetic field which protects the planet from solar winds. The mantle is the large layer of magma. Flows within the magma influence tectonic action on the crust. The crust is the thin, outermost layer of the planet, originally made from mantle cooled as it radiates heat into space with features changing from tectonic activity as well as weather. It's where all living things exist."
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mhaqrp | Why are drives/memory/disks with more storage not physically bigger? | Technology | explainlikeimfive | {
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"They're standardies sizes, especially for hard drives and SSDs, so even if you could fit the same amiunt of storage in less space, manufacturers choose to use standardised 2.5\" or 3.5\" inch form factors to ensure they fit in every case. Same thing for SD cards, they need to be able to actually fit in the card reader so manufacturers can't just go making their own sizes."
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mhbd7u | How do airplane wings generate lift and why is there less of it when a plane angles itself more vertically? | Physics | explainlikeimfive | {
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"Wings bend the airflow \"down\". Technically, they direct it at 90 degrees to the air flowing past them. But since most airplanes are usually level and going forward, that means down. Then Newton kicks in...for every action there is an equal and opposite reaction. If air is being forced down, there must be a force up on the wing. That's lift. That's about it...all the fancy shaping is generally to reduce drag or improve behavior in high lift situations, but anything that bends airflow down will generate lift. A flat plate makes a perfectly decent wing for low lift situations...that's why paper airplanes and balsa gliders work. When the plane angles itself vertically, the aerodynamic lift doesn't change if the airplane maintains speed. But remember that lift is defined relative to the air going over the wing...if the airplane is angled up, the airflow over the wing is at an angle relative to the ground and the direction of the lift isn't straight up. Only a portion of it is pointed up and opposing gravity. If you're flying straight up the lift force isn't helping you at all (it's straight sideways) and you can ditch the wings...hence why rockets don't have wings.",
"Everyone else has covered how wings generate lift, but to the last part of the question. Starting with general aviation: The wings generate lift by having the top and bottom of the wing moving horizontally through the air. If you rotate this 90 degrees so the plane is going vertically, there is a different in pressure between what is now the top and bottom of the wing, however, because of the angle it isn’t generating any lift, and what now was the top and bottom at the original angle are not generating any lift at all and are just weight. The engines on a plane generate a great deal of thrust, but require the lift generated by the wings as well to keep the plane aloft. So, once you go vertical there is no longer lift being generated by the wings, and the engines alone can’t do the work. In military aircraft you maybe have seen planes go fully vertical, as far as I understand that is due to those planes having an engine that generates enough force alone to move the plane and the wings provide lift to reduce the need to constantly need afterburners."
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mhc8br | How does depression cause fatigue? | Other | explainlikeimfive | {
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"The other answers in this thread sound right enough to me, but there's another angle that hasn't been raised yet. From my experience of being depressed for about half my life and thinking about it a lot to try to understand myself. I'm actually doing pretty well right now - less depressed than I've been for about a decade and actually functioning, so woop! The psychology of being depressed (at least in my case - YMMV) involves a significant thread of avoidance. I dislike my circumstances, don't feel confident in succeeding with whatever I want to do etc. and so want to avoid attempting and \"inevitably\" failing. The result of this is a crushing apathy that is felt as deeply physical. The easiest way to avoid doing or thinking (both painful when depression is fucking your brain up) is to sleep. I'm not sure how this works on a physiological / chemical level, but I've certainly felt the sudden extreme need for a nap when I almost face my fears and just can't.",
"Depression is caused by low levels of seratonin, a chemical in the brain that your neurons use to talk to each other. However, these chemicals are used for a wide variety of things rather than specific things (this is why depression and depression meds can have a lot of different effects). One of the things low seratonin is linked to is fatigue. So it's. It quite accurate to say depression causes fatigue, but they can both have the same root cause.",
"From what I've witnessed from a close relative: It is a constant battle against yourself - there are days on which every second is a constant struggle against negative and destructive thoughts which create strong doubts and a feeling of strong guilt. Fighting this uphill-battle almost daily wears you down. Moreso mentally but through the stress caused by depression also physically."
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mhcjmt | Why is it we can use anesthesia to block out pain receptors, but we don’t use a form of anesthesia to help with after work out pain? | Chemistry | explainlikeimfive | {
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"As with nearly everything, there is a cost and a benefit and in this case, it isn't a dollar cost but the cost in terms of potential side effects. Even OTC pain killers have side effects and overuse makes it worse. So if there is only temporary benefits but potentially bad side effects, generally medication is not recommended. The kind of anesthesia used in hospitals, by the way, are really strong medications and cannot be used without supervision by medical professionals. It is unlikely that for a relatively minor situation like muscle aches after a workout that it would be recommended.",
"Pain is the bodies warning system. We feel pain to earn us to stop doing what we are doing. Blocking pain for working out would lead to people damaging muscles since they would not be able to tell that muscle is done",
"Well, you could, if you wanted to. You'd need a doctor to not accidentally die. And it would demolish your sleep cycle. And the side effects would be bad enough to ruin every workout right after you did it. But yeah, you COULD do it. EDIT: By the way, if you're sore for days and days after your workout, then you're going too hard. You don't get big at the gym, you get big in your bed sleeping and healing. The gym is where you break things down. So if you aren't healing well, *then you aren't growing*, period. When I trained guys, the first thing I did was work on their diet and sleep cycles, as improving those alone will get most gym rats better results without even touching their current workouts.",
"Anesthesia is a very delicate thing to administer, so you'd need an anesthesiologist - you can't just eye-ball a dose. IIRC we don't yet fully understand the mechanisms that cause it to work on the body, outside of it blocking synapses (I'm no doctor, I could be misinformed). Also, having a stab yourself with painkillers after a workout would be something a lunatic would do.",
"You typically don't use anesthesia in the manner you are saying. You use analgesics; this is probably what you meant. The answer is...you can, and people do. Analgesic: Painkiller Anesthesia: Controlled or temporary loss of awareness or sensation You can use anesthetics for pain control, but that is for some awful bad post surgical or post trauma pain. Those drugs come with a whole list of side effects that you would rather not deal with unless you really have to. Post-workout pain will never be that bad. For that, just some tylenol or advil will do you good."
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mhdm9d | How can we sustain 300+ million people constantly using water every day? Talking USA only. | I feel like I use a shitload of water on a daily basis for dishes, showering, washing my hands multiple times per day. I can’t imagine how much water is used every day when you multiply that by 300+ million people. Not to mention how much water is needed on a daily basis for commercial use in the food industry, construction, etc. There must be a lot of water recycled on a daily basis. | Earth Science | explainlikeimfive | {
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"There is a gargantuan amount of water in the air, ground and rivers/seas etc. There is just so much water, practically every piece of the environment has water in it. Water, thankfully is mostly a solvent and not chemically changed by being used. It just moved stuff around, so water isn't really ever \"used up\" since its rarely destroyed. Water is the car and most things are just hitching a ride alongside the water on its way. It can become unuesable from contamination. When the car is filled up with trash, can't really use it for a lot of our hygenic purposes so it has to he treated or \"washed\".",
"Water exists in a cycle. In that cycle, \"using\" water doesn't destroy it, it only pollutes it. Weather is the primary natural recycler, and of course many water treatment plants exist.",
"Water gets recycled endlessly by the environment. If you pee in the woods that water is eventually going to rain down on someone else's head."
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mhdozf | Why do websites need to verify if you are a bot? | Technology | explainlikeimfive | {
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"Imagine you work at the grocery store giving out cheese samples. The sign says \"one sample per customer\", but I'm a greedy cheese monster and I want a lot of cheese for free. & #x200B; If I know how to cheaply build robots which can convincingly pretend to be customers, if each and every one of those robots *counts* as a customer, then I can send an army of robot shoppers to take all your cheese! If you want to save your cheese for your human customers, you might start asking a skill-testing question to keep the robots out.",
"So that the resources they provide are not overwhelmed by automated requests. It adds a layer of security and throttling.",
"It's fairly trivial for a programmer to create a script that automatically fills forms. If there was no validation, anyone could create infinite accounts or send contact forms with garbage data and eventually either exploit a promo for new users or crash the server by making it use lots of resources. There are many other possibilities but the main purpose is to stop automatic bots from exploiting the system. Not that a captcha makes it impossible but it does make it harder for most cases.",
"Every time you visit a webpage, a server has to spend a small amount of computing resources sending the page back to you. That's cool; most websites will rarely have too many visitors at once, and those that do will have the server capacity for it. But now imagine you run a website and someone had a grudge against you. By using an automated piece of software (that's what we mean by a bot here, not a literal robot), they could request so many web pages from your server that those small amounts of resources add up and it's using so many resources to respond to those requests that when someone legitimately wants to view the page, the server doesn't have the available resources to show it to them. This is called a *denial of service* (DoS) attack. In reality, this generally happens with many computers, often infected with malware to make them all send requests to this server, in which case it is called a *distributed* DoS attack, or DDoS. So human verification is a way to prevent that happening. Of course, some sites have additional reasons to not want bots, such as social networks, where bots could be used to manipulate the numbers of likes etc."
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mhds13 | If solar sails work, theoretically, would shining a flashlight out the back end of a spaceship accomplish the same thing? | Physics | explainlikeimfive | {
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"*In theory*, but: If the sun is a fire hydrant that's been cracked open, a flashlight is a spray bottle with a busted nozzle. It's difficult for me to impress just how staggeringly more photons the sun puts out than your flashlight.",
"Yes, but it would require a lot of light and a lot of energy to produce said light. You're also getting only 50% of the efficiency from the light, since a solar sail reflects the light while your thruster only produces it, halving the momentum transfer.",
"Yes - it’s called a photon rocket. Here’s the problem with it - the amount of energy required is 300 MW per Newton. That is, to accelerate 1 kg by 1 m/s^2, you need to generate 300 megawatts. (And actually more due to inefficiencies.) So basically, a photon rocket, given anything within orders of magnitude of current technology, is going to be *extraordinarily* slow. If you’re willing to wait, it can be extremely efficient, but you’re not getting anywhere quickly. (And it’s actually not even *that* efficient in many ways.)"
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mhed1d | How do lighthouses actually work? | I've been listening to a podcast where they cover the mystery of the Flannan Island lighthouse and it struck me that i've never actually understood how a lighthouse works other than shining a beam of light at the ocean? How do the ships know what do and how to steer through the water? | Other | explainlikeimfive | {
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"The basic idea behind lighthouses was to serve as landmarks. A ship’s captain would have a nautical map that would show where the shore was, where any rocks or other dangers were, and of course where various lighthouses were. Then he’d use the lighthouses to help navigate. Most lighthouses had a distinct signal pattern, like Split Rock Light on Lake Superior is a single white beam that flashed every 5 seconds. Some had alternating green and white, or were flashes every 3 seconds, or a flash at 3 and again at 10, or whatever. And it was also known how far out from the shore the light could be seen. So again, for example, if Split Rock could be seen 25 miles from shore, and there was a major shallow spot 5 miles from shore, the captain could gauge where the ship was in reference to which lights he could see and how far out he was from them, allowing him to avoid dangers in the dark. Modern sonar, radar and GPS have made lighthouses almost obsolete as far as navigational beacons, but they’re still very cool, which is why so many are on historic registries",
"They don't actually \"flash\". The light is on continuously. It is surrounded by a cage of lenses that slowly rotates at a constant rate, maybe every 30 seconds. A ship in a particular position only sees the light when a beam passes over it. If it is a 5-second light, it will have six lenses that make the light come out like the spokes of a wheel. (On misty nights, you can see the beams that aren't pointing directly at you, too.) The lenses can be unevenly set up so you get a beam maybe at 8 and ten seconds, making a double flash. Charts have all the time periods, colours and locations marked. A particular pattern will only be used once in a big region, so it can't be mistaken. If you can see two lights (or know your course and speed and tidal drift since the previous light) you can use the bearings with triangulation to find your own position.",
"In the olden days, certain areas of the ocean could be very dangerous. There might be areas where the water is mostly deep, but some rocks stick up near the surface, so if you sail through there, you'll hit the hidden rocks and the ship will sink. So, these places get put on maps and ships try to avoid them. But when you are sailing hundreds of miles, it can be hard to tell exactly where you are. It might be dark and stormy, and maybe you know that there is a dangerous area ahead, but it might be 5 miles ahead or 50 miles ahead, so you don't know where to go to avoid it. So, people build lighthouses near the dangerous areas. The lighthouse gets put on the map, so now, when the ship gets near the lighthouse, the ship knows where it is exactly and where to go to avoid the dangerous area. Basically, ships navigated with maps, and lighthouses were like landmarks saying \"you are here\".",
"Around the North Sea at least it is common to have sectored lights where there is a white beam on the safe passage and red and green beams to the sides. Stray into those and you know which way you need to turn to get back to safe water. Others just flash a known pattern so you can identify them. If you can take compass bearings to two lights you can plot your position on a chart."
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mheval | Why measure the carbon-14 works? Are the carbons atoms create some manner in the life of the organism now dead and fossilized? How do we know that the atoms weren't there before? | Other | explainlikeimfive | {
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"The idea behind carbon dating (measuring carbon 14 isotopes) goes on the line that when a carbon based life form is alive, it’s constantly consuming small doses of carbon-14 in amongst all the regular carbon-12, so the “average” baseline of carbon-14 is about steady. Once something dies, it stops taking in carbon at all, so the level of carbon-14 starts to drop as it decays to non radioactive atoms. Since carbon-14 decays at a known rate, an extrapolation can be done, basically working backward from the amount there right now to what starting average baseline is, giving an estimate of age. It’s definitely not 100 percent though, as things like air pollution, both man made and from things like volcanic eruptions, can interfere with the process.",
"Carbon has two forms, carbon-14 and carbon-12. Carbon-14 will decay to carbon-12 naturally and consistently. Through observation, we know that if we have a billion c-14 atoms, after a certain time, half of them will decay to c-12 (half-life). Carbon-14 is created in the atmosphere and there's a consistent ratio of 14/12 in atmospheric carbon. Living beings take in this carbon from the atmosphere. Plants by photosynthesis, animals by eating plants. So animals always have the same 14/12 ratio as the atmosphere when they're alive. As soon as they die, they stop taking in atmospheric carbon and as c-14 changes to c-12, the ratio of 14/12 in their bodies drops. So by measuring the 14/12 ratio of something dead, we can tell very accurately how long ago it died.",
"Carbon 14 is almost like carbon 12 (which is normal carbon carbon), except it is radioactive. While an organism is living, and taking in air, there is a certain amount of carbon in that air (usually in the form of carbon dioxide). A specific tiny ratio of that carbon will be carbon 14. When an organism stops taking in carbon from the environment, the amount of radioactive carbon is locked. There will be no more added. Carbon 14 decays into carbon 12 over time. So when scientists measure the ratio of carbon 14 to carbon 12, the older the sample is, the less carbon 14 will be in it. At some point there is so little carbon 14 we can't even measure it, and we have to use a different element for dating. This is a very long time, several tens of thousands of years."
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mhex4e | how are ICBM tested for their range without causing false alarms? | Say the usa and soviet union in cold war. History has records of incidents were dalse alarms (including one from the sun) almost started nuclear armageddon. How did they keep testing missiles (ICBM) with longer and longer ranges without it being detected as a real missle? Not to mention there are still states that are neighbored by hostile countries and still manage to do their ICBM tests with ranges encompassing multiple continents. How do they manage it? | Other | explainlikeimfive | {
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"Communication Every missile test and rocket launch is publicized with a listed trajectory and launch window because they all look like real missiles because they are! If the US wants to test a Trident missile out they'll put out a public statement saying what they're launching, when they're launching, what is it's end target, and what corridor will it travel in. Any deviation in these parameters is cause for concern by potential targets But each and every sizable rocket launch triggers the launch detection satellites in orbit which watch for big heat signatures of rocket/missile launches",
"If the USA launches from Vandenburg AFB ([ URL_2 ]( URL_2 )) then everyone is basically OK because everyone on the planet knows that Vandenburg is our test facility. Also under START we are required to give nations telemetry that tells them it is a test ([ URL_1 ]( URL_1 )). *To enhance transparency, the Parties annually exchange telemetric information on a parity basis, for up to five ICBM and SLBM launches per year. These measurements of various technical parameters are made to monitor missile performance during ICBM and SLBM flight tests.* If one launches from Wyoming or Montana - we are all screwed, those are nuclear tipped missiles. That is for Russia and the USA, the two nations with the most ICBMs, by far. It gets dicier when we are talking about non-signatory countries, like Israel. Israel conducts missile tests ([ URL_0 ]( URL_0 )) but they tend to be of pretty short range. I don't know for certain, but I am sure they tell Russia and the USA before they do these things, and tell them repeatedly and insistently so as to avoid being nuked into oblivion by mistake. Then there is someone like North Korea, where we don't really know what they are going to do, and if they tell us, we don't believe them in any real way. This is where the MAD theory comes into play, they can saber rattle but if they launch and it even suggests it will hit a major country or ally they will be nuked into oblivion. Only a few countries can launch ICBMs that can hit anywhere in the world, those countries are Russia, USA, China, Britain, and France. Those nations tend to have diplomatic relations which will prevent us from cross nuking each other because of an error. The risk is just too high.",
"Step one, don’t point it at your enemy. Kwajalein Atoll is where the US aimed many of its test ICBMs. It’s a little circle Of islands in the middle if the Pacific Ocean. Really far from Russia and China."
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mhf0ya | Why does Helium have a lower melting point than Hydrogen? | Pure hydrogen is less dense than pure helium. Why does it have a higher melting point? | Chemistry | explainlikeimfive | {
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"Because density doesn't really change anything - it's about how much the molecules are attracted to each other. Helium is a noble gas, with its whole outer electron shell full, and so it has very little intermolecular attraction - less than hydrogen.",
"The phases of a material (solid liquid gas) don't just depend on density, but also on the forces or links between the atoms (i.e. on the orbitals / chemistry of the atoms). So helium atoms generally don't react with other helium atoms, whereas hydrogen atoms usually form covalent bonds (form hydrogen molecules, H2). So these bonds require extra energy to \"break apart\" and get a material from, say, solid to liquid, or from liquid to gas.",
"Imagine that atoms are hyperactive kids and like to run around and play. This is what atoms are like in gas state, they roam and expand to the edge of how you possibly limit them. To turn them into liquid you need the atoms to stick close to each other and stop moving so damn much. So how do you make the kids stick together instead of running around? You can grab them one by one, but they'll just keep slipping away and run. To guarantee it, you need to force them, and a way to force them is to really lower the room's temperature. When the kids will feel that it's cold, they'll realize at some point that a good way to stay warm is to stick really close to each other and still move every now and then and switch places, but not move away again because it's too cold. This is what atoms are like in liquid state. Now imagine that those kids are really snobby kids that don't get along well with each other and prefer to keep their safe distance. Like some stereotypical noble fancy kids. Noble gas atoms. If you use the same method as in the previous paragraph, they might still get closer together but you're gonna need to make the room much, much colder to convince them that their need to stick together is stronger than their will to be on their own. Helium is a noble gas, and hydrogen is not. To convince the helium, snobby atoms to get along and stick together, you're gonna need a far more dire situation that you would in the case of the hydrogen, non-snobby atoms. **Disclaimer: This is a metaphor only. I strongly urge you not to physically freeze your kids when they're energetic.**"
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mhf447 | How do drugs like ketamine or LSD make you "see" life differently | So ive had on LSD some pretty wierd distortions such as seeing things in different colours or my vision becoming like a fisheye, like i had gopro for eyes How does that work? Is your eye changing, like when your pupils get bigger or just signals in your brain interpreting it like that | Chemistry | explainlikeimfive | {
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"Everything you experience is essentially 'made up' by your brain interpreting inputs it receives form all your senses. If you change the chemistry of the brain, such as taking hallucinogens, you change the way the brain interprets signals it receives.",
"It temporarily alters the sensory perception portions of your brain chemistry. You will hear some people refer to \"hearing colors\" or \"seeing sounds\". While hyperbolic to an extent, from their perspective mid-trip, that is actually a concise, ELI5 explanation of what is happening to their brain. There are a lot of factors that will determine if this temporary alteration is fun or scary (good trip v bad trip)."
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mhfejw | if colors are an illusion created by the brain what does the world look like outside the eye. | Earth Science | explainlikeimfive | {
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"\"Look\" is a word for what the eye does and how the brain processes it. The world doesn't inherently \"look\" any way, any more than it \"sounds\" any way or \"feels\" any way or \"smells\" any way. Those are words for sensations, not for physical qualities. We can measure the available wavelengths of light with statements like \"this object emits light in a narrow band of wavelengths around 650 nm\". You would normally describe such an object as \"glowing deep red\". That's not \"an illusion\", it's just the sensation that a glow of 650 nm wavelength light produces.",
"It doesn't look like anything. How something 'looks' is entirely determined by the thing viewing it. So every animal sees the world slightly differently. There's no \"correct\" way for it to look. Outside of senses, the world is basically nothing. It doesn't look, sound, smell, or feel like anything at all.",
"There's not really a way to answer that question. The only reason we see colours is that our eyes have evolved to be capable of detecting a specific range of wavelengths of radiation and our brains have evolved to be able to extract some information from how exactly those waves behave. Outside of the eye, the world doesn't \"look\" like anything - there's just a load of radiation flying around in the form of waves of different frequencies, reflecting off surfaces in specific ways.",
"Colors aren’t an illusion? Not exactly sure what you’re asking. Light waves are real. They exist whether or not eyes see them. But perception of color only exists when eyes come into contact with the light waves and send signals to the brain. So like yellow length waves bounce off a lemon whether there are eyes present or not. It’s only recognized as and names yellow by an observer."
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mhfihk | Why is GPS free to use? | Technology | explainlikeimfive | {
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"In the states here, it's taxpayer funding. I guess I have to go to a quote. \"In 1983, Korean Air Lines Flight 007 entered Soviet airspace after a navigation error and was shot down, killing all 269 passengers. This incident resulted in President Ronald Reagan ordering the Unites States military to make the Global Positioning System available for civilian use once it was completed, so that similar incidents could be avoided in the future.\" [Here's where I got it]( URL_0 )",
"GPS satellites broadcast, they don't communicate. So there's no extra cost to adding a new GPS locator, any more than there's extra cost to seeing up another TV or radio to pick up local broadcasts.",
"The satellites are in orbit anyway (for military purposes), usage only requires processing capabilities on the *client* side and having large swathes of infrastructure world wide rely on US-owned military equipment gives the US government an **enormous** amount of leverage. There is no reason *not* to offer free access.",
"GPS satellites broadcast a signal, and any number of devices can listen to it. It is infinitely scalable, because the same satellites can serve one device or one billion devices without even knowing it themselves. The US government originally put in the satellite system for military purposes, but has since opened it up to the world."
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mhfsnq | What’s the difference between bird and reptile brains? Do birds feel emotions, and if so, do reptiles not? | Biology | explainlikeimfive | {
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"Birds are kind of reptiles with feathers? In a similar way to how mammals are reptiles with fur. Of course, it's a lot more complicated than that, though. Emotions are not hard lines, they're a kind of on an evolutionary scale from instincts. Fundamentally, instincts and emotions are the same thing - hard-wired components of the brain designed to make us do stuff that will increase our chances of reproducing successfully. The difference is likely not one of complexity of feeling, but rather the way these feelings interact with higher brain functions like sapience, self-awareness and language. Of course, this is still very much an active field of research with many theories, but all the currently active theories I know of that are not theological involve an element of base instinct, with the emotion itself being kind of like the result of that instinct being interpreted and rationalised by the brain. This would be something less conscious animals wouldn't do, or wouldn't do to the same degree. Birds almost definitely feel emotions, but they likely do not have the full suite of emotions found in humans, as many human emotions exist as part of living within a social structure, and they may feel some emotions less intensely or less emotionally as a result of having a relative lack of higher brain function. In humans, emotions have been attributed to a part of the brain called the limbic system. It's thought that this system first arose to modulate the fight or flight response (which manifests in humans as fear and anger), and that later emotions evolved from it as greater emotional complexity was required to navigate a more social and fast-paced lifestyle. The limbic system was present in the common ancestor shared between mammals, reptiles and birds, so at the very least any member of one of those groups that hasn't deliberately lost the structure will have a degree of emotional function, although whether that's experienced *as* emotion and not unknowable instinct will vary by animal and is hard to objectively determine. A big difference between reptiles and mammals/birds is that reptiles are not warm-blooded. This gives them a *much* slower pace of life. Warm-blooded animals generate heat internally, which improves the rate at which their cells can do reactions (reactions go faster at higher temperatures) and that's pretty useful. The cost however is a much higher need for food, and therefore a need to be able to obtain food as fast and efficiently as possible, which leads to fast-paced lifestyles and perceptions of the world, and paves the way for really complicated and interesting brain activity, which is required to be good at getting food and allowed by the higher metabolic rate and energy availability. Reptiles are cold-blooded. They gain the vast majority of their heat from the environment, which means their metabolisms go however fast the environment makes them go. This gives them a much lower need for food, and a much slower pace of lifestyle. This is how reptiles are often able to go months or even sometimes years between eating, where mammals and birds must eat sometimes as often as several times a day. A slow lifestyle like this doesn't need a really active brain though. Such a thing would be a disadvantage even - brains burn a ton of energy and the reptile doesn't have the independence necessary to be able to hunt food that much. Complex brains would be a detriment to a reptile, which values energy efficiency above all. This most likely limits the range and degree of emotions they experience, because they need a brain that will do the job cheaply. As for crows - they're smart as shit. Of course, birds in general are smarter than reptiles in general, but crows are good even amongst birds. They have the ability to make and use tools, to recognise faces (including other crows) and form \"friendships\", to learn by observing other crows and to solve problems to a pretty sophisticated degree, like understanding that you can raise the water level in a tube by dropping objects into the bottom of it."
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mhfyxa | Statistical Significance vs. non-significant | What exactly does it mean when a result is statistically significant vs. insignificant? When we compare, for example, a t-stat and the critical t-value, I know we either reject or fail to reject the null hypothesis based on whether the t-stat is less than or greater than the t-value. What exactly does it mean when the t-stat is greater than the critical t-value? What even is the "t-stat" and "critical t-value" in layman terms? After doing enough problems, I'm sure I'll get it, but I don't like \_not\_ being able to explain this to myself simply - which indicates that I haven't understood it well enough. Can someone please dumb all of this down for me and truly explain it to me like I'm a child? | Mathematics | explainlikeimfive | {
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"Nonsignificant - could just be noise. X and Y can't be said to be different. Statistically significant - can be said to be different. Might or might not be a big difference, but X and Y are not the same. Probably better explanations out there."
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mhh420 | In the Southern U.S, why does a Biological Scientist at a medical lab or university make $13-14 an hour and a Team Member at Target makes $15-17? | Economics | explainlikeimfive | {
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"Because biological scientist isn't an in-demand job. You're basically researching plants, animals, microbes, etc. It's a research job and research isn't very well funded unless it has a direct pipeline to economic return on investment, or strong case for public good (i.e. aerospace and defense as opposed to studying the mating habits of bullfrogs).",
"Likely because target is a corporate chain. Being a corporate chain, they have standards and try to set standards on a wide scale, and it is good publicity if target gives their employees that 15 dollar minimum wage. And they do it across the board, not just in expensive cities, but also more suburban/rural places to avoid the bad headline “target pays its city workers more than they pay everyone else” because that might piss off people who don’t live in the city, even though it makes sense. A medical lab or university doesn’t have that same kind of concern, it’s just a single lab or single university with a budget that they have to balance, maybe they can only afford to pay their employees so much. Maybe they don’t have that same pressure to raise wages because good PR won’t help them. For Target, good PR and good Publicity will hopefully make more normal people go to their stores. For a medical lab, good PR or good Publicity isn’t going to get them any extra money, because the general public isn’t regularly going to a medical lab."
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mhh4td | why genetic diversion between several groups of people is less than within one | I saw it mentioned in several books that, for example, I’m (as a human, who I totally am) more genetically diverse to people living in my country than to people living across the ocean. How can you explain it or did I just get it wrong? My brain (of course only one, as we all have) can’t understand it, because the opposite seems more reasonable. Btw we love this sub. Thanks. | Biology | explainlikeimfive | {
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"I think this more to do with there being more differences within groups than between groups. So it's not that you, as an individual, share more in common with someone from a different group than with someone from within your own. It's more that differences within one group can be large but that average difference between groups tends to be small. Genetics is kind of complicated so think of it like something else. Men tend to be taller than women. In the US, the average man is 5'9 and the average woman is 5'4. An average difference of 5 inches. But within those two groups there can be very big differences. So you can have a women who's 5'9 and another woman who's 5'0 - a difference of 9 inches. It's not unusual for women to be these heights. So there can be much bigger difference between individuals within the group than there is, on average, between the two groups."
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mhhog3 | How do colours work at subatomic levels? | I searched for it but couldn't get anything. I know that if some material is a shade of green colour then light of every other wavelength other than that shade is absorbed. Also that the colour appears due to the visible electromagnetic radiation by de-excitation of electrons. What I don't understand is: Why do electrons keep oscillating between higher and lower states? Electrons can move from one level to another level by emitting photons of different energy. For example for level 5 to level 1, it can go 5- > 3- > 1 or 5- > 4- > 3- > 2- > 1. So why is the apparent colour consistent? A blue pigment absorbs yellow light. So electrons absorb yellow light to excite but give off blue when de-exciting for the same transition. How does this hold conservation of energy? Would there be any observed colour difference if the same light bulb is kept in a blue room with blue objects and then a yellow room with same blue objects? Thanks for helping. | Chemistry | explainlikeimfive | {
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"If a light wave of a given frequency strikes a material with electrons having the same vibrational frequencies, then those electrons will absorb the energy of the light wave and transform it into vibrational motion. During its vibration, the electrons interact with neighboring atoms in such a manner as to convert its vibrational energy into thermal energy. Subsequently, the light wave with that given frequency is absorbed by the object, never again to be released in the form of light. So the selective absorption of light by a particular material occurs because the selected frequency of the light wave matches the frequency at which electrons in the atoms of that material vibrate. Since different atoms and molecules have different natural frequencies of vibration, they will selectively absorb different frequencies of visible light.",
"> A blue pigment absorbs yellow light. So electrons absorb yellow light to excite but give off blue when de-exciting for the same transition. No. A blue pigment absorbs yellow light and *reflects* blue - it doesn't emit blue. But the behavior you're describing, of single discrete energy levels that are constant for each atom and no other means of dispersing energy, only apply to *isolated* atoms. An atom in a low-density gas way out in space does behave that way, and so a 1- > 4 transition would either go 4- > 3- > 2- > 1 or 4- > 3- > 1 or 4- > 2- > 1 or 4- > 1 (emitting higher-wavelength light in the first three cases). But atoms in materials have other ways to disperse energy. They have internal higher-energy states, centered around things like the spin-orientation of their electrons (although these states tend to decay pretty quickly). They have strong bonds to other atoms in the same molecule that are somewhat 'elastic' and can absorb energy by stretching or twisting. (This is how the proteins that detect light in your eyes work - they have a bond that twists when they absorb a photon.) They have weak bonds to the overall structure of their parent material that can do the same. And so on. So an electron can absorb energy but then release it in forms other than photon re-emission."
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mhi414 | How do we get other pictures of far away galaxies that we can not see? | Other | explainlikeimfive | {
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"Long exposures with cameras using powerful telescopes. Many galaxies and other celestial objects are too faint to see with the eye, or with a regular camera. But if you let a camera have a long enough exposure these faint objects reveal themselves in the picture taken by the camera.",
"Imagine that you eat a big burger. Will eating just one make you feel full? Probably yes. Imagine that you eat popcorn. Will eating just one make you feel full? Probably not. However, if you keep eating more and more and more popcorn, at some point it will end up getting you full. Replace the food with light and your stomach with a camera. Will opening your aperture for like ½ a second make the camera absorb enough light to get a clear picture of the moon? Probably yes. Will doing the same with a far away galaxy be enough? Probably not. However, if you expose your camera to the galaxy's light for a sufficiently long period of time, at some point enough light from it will gather up to give you a clear picture of it. Edits - spelling and typos",
"Often they use radio telescopes using wavelengths other than visible light, but we can \"see\" them just with additional assistance.",
"Big telescope capable of detecting faint light with long exposures and accurate direction. Launched up in space so the atmosphere doesn't distort the view. Probably a bit of image processing to remove the last bit of distortion. You end up with this, most of the blobs are separate galaxies billions of stars in each. URL_0"
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mhig5s | Which came first spooky music, or music we think is spooky? | Okay, so when you hear a song, let's say In the Hall of the Mountain King - it's a little bit spooky, a little bit creepy-crawly. Does the music sound this way, and we feel this way because of the inherent sounds themselves? Or have the particular instrument/note combinations been so frequently used for spooky situations that we now automatically associate it as spooky music? The same can be said for anything really, 'space' music, romantic music, sad music. Which way round is the association? | Other | explainlikeimfive | {
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"I believe music came first. The whole gothic sounds that are in say Skyrim and such were once a genre people listened to in church and festivals and such. Then today we feel freaked out. One day Tupac may be the battle music for a dragon fight It was associated with the era it was in. Gothic and ruins hand in hand. Space in the 70s trying to imagine what the future thought would be cool. It’s just what we imagine each sound deserves. I guess that goes there",
"There is a concept called \"reification\". An example is the Star Wars theme. When you hear it, you think of Star Wars, not the music as it is. You represent the abstract music, which has no such association on its own, as a concrete thing, in this case a movie world. As a 21st century person, you've probably grown up watching TV. All those cartoons have backing tracks which programmed you to assign feelings to certain chords, modes and methods of musical resolution. For instance, this does not sound like a wedding to me, but on a certain subcontinent they would disagree. [ URL_1 ]( URL_1 ) I dunno, other people can explain it better, like this guy who actually knows a lot about music. [ URL_0 ]( URL_0 )"
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mhikla | If bacteria such as salmonella and ecoli are killed from ground beef when it’s properly cooked then what gets you sick if it’s left out too long after it’s cooked? | Biology | explainlikeimfive | {
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"Other bacteria in the air settling on it, multiplying, and generating waste products. Why don't those bacteria make use sick when we just breathe them in? Because we are breathing them in at very low concentrations, so our immune system/gastrointestinal tract can deal with them. It's a bit like having an enemy army attacking yours one by one vs all at the same time. If you're fighting the enemy one at a time, you have a much better chance to beat them than if they swarm you.",
"Other bacteria. There are contaminants on surfaces and in the air. We don't normally keep our food in sterile environments."
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mhim9x | Why does Delayed Onset Muscle Soreness (DOMS) happen with muscles? Why does it take your muscles 12-24 hours to become sore and feel pain, whereas with injuries the pain is instant and doesn't buildup slowly over the days | I just went to the gym this morning, and now I'm beginning to feel the pain. Afterwards I felt my muscle being fatigued and weak but there was no soreness/pain. Now 12 hours later I'm begging to feel the pain and by tomorrow morning I will be in a world of pain. Why does this happen? | Biology | explainlikeimfive | {
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"Source DOMS pain is from inflammation, which is need time for immune response to release specific agent (Prostaglandin E2) so we can feel pain. For usual injury, we feel pain directly from stimulation to nerve pain.",
"Instant pain from “damage” of any sort to the body is caused by nerves, and is evolutionary in nature...to teach us with instant feedback HY we shouldn’t stick our hands in fire, or cut ourselves, or whatever. Pain from exertion is caused by other root causes listed by others in other posts, and again, are delayed due to evolutionary reasons. If you felt the pain of the exertion instantly from sprinting, you wouldn’t do it, and would have been eaten by whatever was chasing you!"
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mhipoa | Why do shots feel different for different people? | When I get any kind of shot or vaccination they always say it'll just feel like a pinch, but for me I can feel whatever is being pushed into my arm and it's horrible. When I got a flu shot with my mother she said that it only feels like a pinch for her, nothing else. Why does this happen? | Biology | explainlikeimfive | {
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"Some people are just tougher. Or maybe they don't take the \"just a pinch\" literally. I can always feel the poke, sometimes the slide of the needle, and sometimes the goo going into my arm, and sometimes the removal of the needle. I've never had a shot that lasted more than a few seconds, so it's easy to such up the momentary ouch. Sometimes the goo is just filling a space, so there's a little pressure. Sometimes there's a perceived or real change in temperature. Sometimes whatever it is gets a little disagreeable and can seem to burn. The bulk of that is briefly uncomfortable, and usually returns to normal really quickly. If there's any lasting impact, it's usually an ache, like I bumped into something or lifted something too heavy or for too long. Rarely, but it happens, that initial jab is less than careful, and it's a definite, but small, stabbing pain. It, too, will subside quickly. I've received hundreds of pokes for injections or blood tests by now. The worst were in the assembly lines in school as a kid, or maybe in basic training. But they still only lasted a few seconds. Anyone should be able to handle a few seconds of horrible that doesn't usually lead to permanent damage."
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mhirkl | When you eat something that upsets your stomach and makes you feel ill, how does your stomach know that it doesn’t like it? | Biology | explainlikeimfive | {
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"It's not really your stomach doing that. Generally something toxic or at least irritating gets into the bloodstream and starts affecting other things and the body says that it needs to prevent any more that may still be in the stomach from getting any further.",
"I feel like its more the other way around. Your stomach isn't saying oooh pain it's trying to digest, either making the fluids more acidic or ramming the digestables down faster. Your brain after a few generations of evolution was like maybe we can build feeling responses to this reaction. To say stop eating it you dumb nuts. But we never listen."
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mhiut1 | What happens if you hit the top of the bottle beer, with another bottle beer, in SPACE? | Physics | explainlikeimfive | {
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"Assuming you mean on the ISS which is pressurized to the same pressure as Earths atmosphere would likely still experience cavitation and allow for the dissolved C02 to quickly form bubbles and fizz up as it tries to escape. In a vacuum, it would likely just spontaneously do this upon exposure as all the dissolved gasses would immediately try to equal out the the pressure difference."
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mhjvaa | What do you need to provide a professional Dungeon Master when you want them to run a homebrew campaign? | Other | explainlikeimfive | {
"a_id": [
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"text": [
"There is no such this a professional dungeon master. Anyone who claims to be such is the worst kind of person who will be a guaranteed disappointment. Just run a game for your friends, it's a game for ages 8 and up."
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mhk4li | Why does the water in the pool feel so cold at first, but after a while, it's room temperature or even warm? | I've been a competitive swimmer for almost 4 years and I still don't know why this happens. | Other | explainlikeimfive | {
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"Water conducts much better than air so when you go in your skin will cool quickly, so it feels cold. But after that your skin will be settle in an equilibrium with the water and the heat in your body, at a lower temperature than in air (depends on water temperature of course) so you don’t feel cold.",
"On the initial cold-shock the capillary blood vessels contract and reduce the blood flow from your extremities to your body core so that less of the blood that has been cooled by skin contact with the cold water gets to your vital organs.",
"We don't have the ability to sense temperature, what we can sense is the rate of heat transfer too or from our skin. Cold is heat transferring from our skin, hot is heat transferring into our skin. When you first jump into a pool of water heat is leaving your sin quickly so it feels quite cold. Once you have been in for a bit the temperature of your skin evens out to the temperature of the water as well as a few physiological changes that slow the rate of heat your body looses to the water so it doesn't feel as cold."
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mhk73k | If DNA is identical in all cells of a living organism, what makes some cells become specialized? | I understand that my DNA is what defines me, what makes me me. However, why do some cells become skin cells, others become hair cells, others gut? | Biology | explainlikeimfive | {
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"Imagine having a recipe book but each specialized cell only uses one recipe. To get what you need done you only do a hand full of recipes but you have them all in a book Certain cells turn off parts of the dna or activate others. The information to everything is in every cell but not every cell uses everything.",
"Cell differentiation is also coded for in genes. As an embryo grows the stem cells divide next to other cells who send chemical messages that say \"you're in the heart, so you better become a heart cell or we'llboot you out\"."
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mhknz5 | Because the Earth is spinning, is there technically a point at both polls where you could stand still and the earth would spin you around in circles? | Earth Science | explainlikeimfive | {
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"Sure, that's what's happening when you stand at either pole. You wouldn't feel it because the ground's rotating under you and you turning with it. (eta: or in the case of the north pole, the ice under you.) But if you watched the sky above you, and maybe took a long exposure photograph, you would see that all the stars are spinning in what seems like a circle right around you. (of course it's not them that's spinning, you are!)",
"Not quite. Or at least, there is at any instant, but that point moves around (very slowly and over short distances), so you would have to follow it. The Earth doesn't spin perfectly, it wobbles slightly. There are three main kinds of wobble; an annual wobble, a thing called the Chandler wobble (that repeats every ~435 days), and a gradual drift. This polar drift used to be heading Westwards (and shifted about 20m during the 20th century), but since 2000 seems to have changed direction, possibly related to global warming shifting water mass around. But yes - ignoring that, there are two points - at the poles - were you could stand and you'd spin around once every day."
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mhl0q8 | Can plants/trees live forever? | Suppose you plant a tree in a place where the conditions stay ideal forever, i.e. nutients doesn't decrease, amount of sunlight is always perfect etc. will it eventually reach the end of its lifespan or will it grow forever? | Biology | explainlikeimfive | {
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"The upper age of some species has not been measured, and might in theory be indefinite. It's tough to be sure. Clonal colonies like Pando can keep going as long as new clones are made to replace ones that die. But even among individuals, there are some trees and bushes believed to be thousands of years old. It's not clear if an upper limit even exists.",
"Most species of trees have a life expectancy. Pick a species and Google its lifespan. Some are 50 to 60 years and then there's the Alaskan red cedar that can go as old as 3,500 years. They're all different.",
"Not sure anyone can answer that definitely. There is a 5000 year old tree in the middle east."
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mhlf89 | How does our imagination work? | To expand on the question : how can we see and create images, recreate or create sound and smells in our head? | Biology | explainlikeimfive | {
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"Not eveyone can. Some people can't create images in their head, they dont think in pictures. some people can create images but not color images. Some people only see stills like photos, while others can Create entire 3d environments and objects and manipulate them like its on a computer. some people cant play music in their heads. Some people cant even talk to themselves in their head! Brains all work very differently, and people are constantly studying it to understand why people think is such different ways and what advantages and disadvantages different ways of thinking might have on someone, and why the brain develops one method of thinking over another. And that didnt answer you question at all..",
"Okay so you have in your head millions of these little zappy balls that like to zap each other in specific patterns. Each time they zap in a specific pattern your brain has specific thoughts, actions, etc. When you see hear and smell new things a new pattern is created and added to the list of patterns you already have. When you sleep your brain takes these patterns and tries to make sure you don't have too many patterns and gets rid of or combines them if it can. It is very busy doing this all night which is why you need lots of sleep if you do a lot of learning. But when you imagine things or daydream or remember things you are forcing you brain balls to zap each other in a specific way from your list of patterns. If you do this a lot you will sometimes change the pattern slightly or combine it with other patterns it's running as your body is still breathing and stuff. Which is why studying and chewing gum or whatever is a good memory trick cause your brain zappy pattern for that is used very often and has deep marks left to fill with other stuff temporarily. Imagination is of new things is when your brain takes common patterns you know very well and mixes then up because they have interlocking parts, like legos. If you have a particularly efficient brain that breaks everything down as much as possible you end up with artists, inventors, actors, etc. People whose zappy balls have organized themselves and their patterns in a way that allows them to build better lego models because they have more pieces and more unique pieces. Eventually your zappy balls cant produce enough electricity to zap and then memories will be incomplete as the pattern isn't working anymore due to one ball not zapping. Which is why when your memory starts to fail when your older it can be random unrelated things and not sudden complete amnesia (which is when you lose access to the list of patterns from injury or other things.)"
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mhltfq | How can hydrogen have a cation if its literally just a proton? | After losing its electron is there still something identifying it as hydrogen? Are all lone protons just hydrogen cations? | Chemistry | explainlikeimfive | {
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"gszldsc",
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"A single lone Proton is Hydrogen, with or without an electron. It's a cation because it has a positive charge. Specifically it's H1 or Protium, while Hydrogen with 1 Neutron is H2 or Deuterium, and with 2 neutrons it's H3 or Tritium which is radioactive.",
"A hydrogen cation is often called called a proton, because unless it is deuterium or tritium it *is* a lone proton. There really aren't a whole lot of lone protons floating about, except in solution."
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mhm09x | how tax write offs work | So I ordered shoes through my work place and via my paystubs I absolutely don’t understand So boots cost 200$ First week they took 50$ out of my check (as I expected) Then the next week my check was 200$ more, on inspection, it showed normal taxes being deducted from, then it showed “Shoes +200$” as if it just paid for the boots from my taxes? But proceeded to give me the money? Then the following week they took 25$ from my paycheck So I truely havnt a fucken clue what’s happening rn | Other | explainlikeimfive | {
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"This sounds like something you should get clarified through your HR. Depending on your occupation, but most companies aren’t required to pay for your work boots. You can write your work boots off on taxes, but I’m not sure if you can if your company is covering the cost. It sounds like you need to talk to someone at your company to figure out what they paid for, and then proceed from there",
"This sounds more like a reimbursement than a write off. Reimbursements are not taxed as somehow the government sees the money as already taxed. Least greedy thing they do. To answer the original question: you earn money (taxable income) which derives your tax burden (money government will steal from you). Write offs are used to reduce your taxable income and by extention your tax burden. For the small fry like me I would have to file line item deductions, and those deductions would have to exceed the standard deduction for it to be worth my time to try.",
"Because you need the boots for work, you can exclude the cost of it from your income when filing for taxes. What you're describing is your workplace compensating you for the cost of the boots. On the pay stub, you should have the initial amount which is what you were promised for your pay. One of the sections after that is a rollup of all the additions/deductions. Although your taxes normally show up as a deduction in this section, this section isn't exclusive to taxes. As for tax write offs, if your company didn't reimburse you for the boots, you can claim in your tax filing. As an example, let's say that you make $10,000 over the course of the year. As such, you will normally owe taxes on $10,000 and the tax bracket that you fall under is based on that $10,000 amount. If you paid for the boots out of your own pocket, you can claim that $200 as a workspace expense. As such, the taxable amount and the tax bracket you fall under will be based on an overall $9,500 income. In the future, recommend you post stuff like this in /r/personalfinance/"
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mhm4k6 | if I created a BBQ sauce and used a copacker, could they just steal my recipe | I had a bbQ recipe I wanted to monetize. If I got too big and used a copacker, what is actually stopping them from recreating my recipe? Their lack of marketing? Make more money as a copacker? Fear of being sued? I just dont get the basics I guess. | Other | explainlikeimfive | {
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"gt002i8"
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"Pretty much nothing save for any caveats in any contracts you sign. Recipes aren't patentable. What is patentable is any novel process you invented to produce the sauce. The other company just has to suddenly decide to drop their current contract packing business plan and decide to compete with you. Possible but it's not a very good risk/reward proposition."
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mhmf7e | why does freezer burn occur? | Chemistry | explainlikeimfive | {
"a_id": [
"gszq63g"
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"text": [
"Ice crystals are sharp and poke little holes in your food. The longer something is frozen, the bigger and pointier the crystals get, and eventually the food is so full of holes that it is ruined."
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8
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mhmqm4 | How do you tell the difference between music genres? | Edit: Totally redone since people seem to think I'm completely stupid or something. How do you tell the difference between closely related genres? For example, I saw an artist listed as "pop, bubblegum pop, indie pop, pop punk, electropop" and I don't understand how those are all different genres. Or you have rock, punk rock, grunge rock, and alternative rock. Like what themes or instruments or whatever defines these genres and makes them not the same as all the others? | Other | explainlikeimfive | {
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"So for the instrumentation part I'd honestly just Google the various genres and see but for any genre its usually it has something to do with how the music was generated, the instruments used, the general speed and mood of the lyrics, the note structure, the percussion choice and a few others. It's really very subjective for some bands as well. Go here and just experiment for a better understanding URL_0",
"At a very high level, the larger genres (classical, rock, jazz, rap, etc) are all pretty easy to tell apart based on the traits they have - the instruments used, the rhythms, vocal styles and so on. When you start subdividing the genres, you are just being more specific about how you classify them, and are typically referencing elements of the music that are perhaps less obvious to casual listeners but clearer to devoted fans. So a metalhead will quite quickly be able to listen to a band and tell you whether they are thrash metal or black metal based on the differences in things like the guitar playing or vocal styles, while to an outsider they basically sound the same as they are not so attuned to the general style or differences between them. The trick is in realising that ultimately there are no rules or guidelines to genre classification, other than what is haphazardly mutually agreed by the masses. The band you may consider as garage rock, someone else may classify slightly differently based on their own ideals of what each genre should sound like. So while the bigger overarching genres are pretty set through common consensus over the years, the deeper you go into subgenres the more disagreement you will find."
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mhnkh3 | Why do some TV shows hide well known logos with tape? | Other | explainlikeimfive | {
"a_id": [
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"text": [
"> What legal repercussions could happen if they don’t tape up the logo? Nothing. The Apple logo is trademarked but that only prevents you from slapping the trademark on your own products, it doesn't prevent you from incidentally including the logo in a video you produce. Some logos are also protected by copyright. If all you're doing is videotaping a copyrighted logo up close then that is actually copyright infringement, but in the case of your documentary that's not what's going on. You are allowed to use a copyrighted work if your use of the work is \"transformative\". That doesn't mean what the internet thinks it means, but its extremely clear that if the copyrighted logo is incidentally recorded as part of a documentary interview then showing the logo in that context is \"transformative\" within the legal meaning of that term. So why do they do it? Its an industry standard to block out the logos because broadcasters can, and do, charge to have the logos unblocked. That doesn't mean that's why your particular documentary did that. A weird thing about human nature is that people tend to copy whatever the biggest person in their industry is doing. Sometimes this results in weird behaviors because people copy things without understanding why they're copying them and that sometimes leads to behaviors being copied over into circumstances where the behavior isn't necessary. So for example, its possible that your documentary didn't have any real reason to block out the Apple logo but did anyways because they saw the big TV networks doing it, didn't understand why it was being done, and assumed that there was some legal purpose for it even though there was not."
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mho9vp | Why is it that dreadful tasks such as house cleaning and organization suddenly get done when deadlines for pertinent tasks (studying for exams, work projects) get closer? | Other | explainlikeimfive | {
"a_id": [
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"So assuming you’re talking about procrastination the reason we procrastinate is because the task we need to do brings up strong negative emotions for us (fear of failure or embarrassment or just not knowing if you’ll be able to complete the task) so we choose to do something else that doesn’t bring up those emotions like cleaning or exercise because they feel easier than facing the emotions even though they aren’t fun activities."
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mhojo2 | How do people upscale 24/30 FPS animation to 60 FPS ? | Mostly talking about in some anime openings and edited scenes, like this one URL_0 . Do they really go in and draw extra frames, or is there a program that just adds in extra scenes? | Technology | explainlikeimfive | {
"a_id": [
"gt0364d"
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"text": [
"The easiest would be just copy and paste previous frames. There are also programs that does motion smoothing and would fill in the frames in between. This is known as the soap opera effect."
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mhooyn | Why does scratching the right spot feel so heavenly? And why is it that over-scratching can turn suddenly excruciatingly painful? | Biology | explainlikeimfive | {
"a_id": [
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"text": [
"Itching is the skin's way of getting you to scratch your skin. Maybe there's something digging in there that itching will dislodge or something to that effect. So, positive reinforcement for scratching via endorphins.",
"When you scratch it, it is relieving an irritation. I have never felt over-scratching as excruciatingly and I have butchered my skin from severe eczema on occasion. Sometimes the bleeding skin feels better than the itch in my experience. I am interested in how people feel sensations though. Itchiness is normally felt when in the stage of healing. Scratching unless it is done very mildly (like exfoliation) is not good for the skin at all - it tears and thins it."
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mhoqjs | Why is it hard to cut something from the outside, but if you punch a hole it's suddenly much easier? | Let's say I take a tube. If I try to cut with a knife, it just wont work. However if I take the tip and cut a hole, I can then suddenly cut with the knife the entire thing. | Physics | explainlikeimfive | {
"a_id": [
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"text": [
"You're taking the same force that was once low pressure on a large area, and turning it into high pressure on a low area. That gets you into the tube. Then, you already have a material failure, and things hold together better when there's no failure points."
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mhp303 | How do chemists find out whether or not a chemical is toxic without, well, ingesting it? | Chemistry | explainlikeimfive | {
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"Ok, chemists are told not to lick the science. So they suggest others don’t either. In all actuality, lab testing routinely involves animals and since our closest relatives besides monkeys are mice, if a mouse ingests it and they die it is likely to hurt humans too. ETA: yes, I am a sci dork who forgot to mention why we use the mice/rats outside of similar digestion. 😣",
"Scientist pretty much determine if a chemical is toxic by taking a reference group of animals and check at which dosis kills half of the population. The measurement is called Ld50 (lethal dosis, 50%). By taking the biomass of mice for example into account a lethal dosis for humans can be determined. This is not always reliable due to physiological difference between the two, so sometimes they check the dosis on human tissue cultured in the lab. All chemicals are toxin when breaking a certain threshold."
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mhp5ul | Why do we really get goosebumps? | Biology | explainlikeimfive | {
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"Your skin hairs have muscles whose purpose is to make them stand up. In our much hairier ancestors, this had a dual purpose--it would make the fur much thicker and thus better at trapping heat in the cold, and it would also make the animal look larger and more threatening. Humans still have the same instinct to raise their hair if they're afraid or cold, but because we have so little hair, we just see visible bumps on the skin instead."
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mhpa0t | The difference between RGB and RYB. | I always remember learning that the three primary colors are Red, Yellow, and Blue. Many people rather insist that they are Red, Green, and Blue. When you take paints or markers or something else along those lines, combing RYB will give you all the colors, whereas RGB will not. Furthermore, electronic displays and lights use RGB as their primary colors, not RYB. So what exactly is the "true" set of primary colors. Or are there just two sets that function differently? | Technology | explainlikeimfive | {
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"There is no RYB: printers use CMYK (cyan, magenta, yellow, black). Kids get taught that it's red and blue because those are familiar colours but the technical names as magenta and cyan. CMYK is the system for use with paints and inks, i.e., for subtractive colour mixing. You start off with a white canvas and each layer of paint subtracts a colour: * cyan + magenta = blue * cyan + yellow = green * magenta + yellow = red * cyan + magenta + yellow = black (but not a very good black, so we use black ink) If you're starting off with a black screen and using light to add colours, then you use RGB (red, green, blue). This is additive colour mixing as used on computer monitors and TVs. * red + green = yellow * red + blue = magenta * green + blue = cyan * red + green + blue = white So there are two completely different (in a sense opposite) sets of colour primaries: additive and subtractive. The one you use depends on how you're creating colour.",
"It's a different function. If you're talking about additive colours, as are used on your computer display, then you use RGB--red and green together will make yellow, etc. For printing, the colours are subtractive (they're absorbing some part of the incoming light), and the base colours there are actually cyan, magenta and yellow, not blue, red and yellow.",
"Primary colors are simply any set of colors that can reproduce all other colors by mixing them. The way of mixing defines what colors are primary colors. In paint the way of mixing is subtractive as each pigment of paint - absorbs - \"all but one color\" so a red pigment absorbs all light quite good except for red light which is reflected back to you, thus you see the paint as red. So when mixing paint together more colors are absorbed, thus more colors are subtracted, from the color pool. Due to this behaviour the primary colors of subtractive color mixing of paint in art and design are Red, Yellow and Blue. (This is not the whole spectrum though) However everything that - emits - light mixes by - adding - colors to the pool. So a red light emits \"only in the red\" and a blue light \"only in the blue\". Thus wenn mixing them together you receive blue and red data. So this way of mixing is - additive - and here the primary colors are Red, Green and Blue. So to say \"those are the primary colors\" without mentioning the way of mixing is simply wrong. The definition literally states \"any of a group of colours from which all other colours can be obtained by mixing\". Thus there are no \"real\" or \"unreal\" primary colors. It simply depends on the way these colors are mixed and if all other colors can be obtained. So in the end what colors are considered primary depends on the so called \"color model\". The most common ones are the paint (subtractive), light (additive) and ink (subtractive) models.",
"Primary colours is basically just a set of colours that produce some *gamut* of colours by mixing the primary colours. This means that basically any set of colours can function as primary colours for the gamut that these colours may create. You can technically even have only two or one primary colour for a gamut, although that would be pretty useless (in the case of only one primary colour, the gamut would consist of only that colour). One important fact to note is that it is practically *and* theoretically impossible to create *all* colours from a finite set of primary colours. So no, there are no 3 (or any finite number of) colours that can create all other colours. Any colour gamut is fundamentally arbitrary, but we of course try to create gamuts that cover as much of all visible colours as possible using the technology we have. RGB is often used in screens becasue it covers a large amount of the visible colours and we have the technology to create red, green and blue pixels using e.g. liquid crystals (LCD) or LEDs. Take a look at this review of an LCD-panel over at Rtings: [ URL_1 ]( URL_1 ). Here, they look at at how well the monitor covers at least 4 different colour gamuts, all of which are a type of RGB-gamut (since the panel has red, green and blue pixels): SDR gamuts \"sRGB\" and \"Adobe RGB\", and HDR gamuts \"DCI P3\" and \"Rec. 2020\". Of these gamuts, Adobe RGB is wider than sRGB, i.e. it covers more colours. Similarly, Rec. 2020 is wider than DCI P3. Regarding human vision, we have three colour photoreceptors. Contrary to popular belief, each receptor can actually \"see\" more than one colour. Each receptor responds differently to different wavelengths, see this picture from wikipedia: [ URL_0 #/media/File:Normalized\\_Cone\\_Sensitivities.png]( URL_3 ) Take a look at the L-receptor. It responds most strongly to yellow, but it also responds \"sees\" red and green, and even blue although very weakly. Depending on the responses of the three receptors, our brain constructs an image in our minds. But again, there are no \"true\" primary colours. Animals may have different, or even more, photoreceptors, which for example allows certain birds to see ultra-violet, i.e. colours that humans *cannot see* at all. As others already have explained, creating colours from primaries also function differently depending on whether you use additive mixing (you produce light using some sort of lamp, e.g. a LED or LCD) or subtractive mixing (you remove light by adding e.g. ink/paint). Note that additive mixing is in a sense independent, i.e. the lamps you use shine with the colours that they shine, period. In subtractive mixing, you have some light source (e.g. the sun) that shine on your painting or whatever. The light from the sun is a mix of colours, and then you add paint to *remove* some of the colours from the light so to speak. This means that the colours you get depend on the colours existing in the light from which you remove colours, and also their relative intensities. If you swap the sun for a blue-ish LED-lamp, the colours of the painting will look different even if you have the same paint on it. Basically, a red painting only looks red as long as the light source shining at it actually contains the colour red (or some combination that the human brain would percieve as red). Here is a link to the rather good wikipedia page on primary colours, which I base a large part of my answer on: [ URL_0 ]( URL_4 )"
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mhq4ny | what is happening when old school box televisions mess up and you slap em' up to fix them? | Technology | explainlikeimfive | {
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"Older TVs had more electrical connections that were susceptible to oxidation resulting in poor contact. Smacking the TV created small movements that would break through the oxide barrier or otherwise help restore solid electrical connections.",
"Good old percussive maintenance! A connection gets loose or otherwise degrades. Giving it a jolt can sometimes reestablish those connections. They're big and flexible, which is why they got loose in the first place. Why doesn't it work now? The connections are less likely to get loose or degrade. They sometimes break, but slapping won't help that. Why? Less heat, so damage is less likely. Different kinds of connections - modern electronics have small, rigid chips soldered, at several points, to rigid circuit boards. If a solder point breaks, it's because something is pulled it apart. A slap won't stop the pulling. Plus, in a high-speed system, an imperfect connection may not work at all because of capacitance; it's often not enough for the metal to just be touching, it needs a clean enough connection that charge doesn't build up around it. So even if an angry right hook could make the pieces touch, they would fail anyway."
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mhqeim | Why does hearing yourself speak with a few seconds of delay, completely crash your brain? | Biology | explainlikeimfive | {
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"We subconsciously use our own voices to make sure our mouth is making the noises we want it to. The brain can’t figure out what’s wrong but still tries to correct itself",
"Professional TV audio engineer here, for guests that appear on TV shows \"remotely\" a special mix has to be sent to their earpiece called a \"mix-minus.\" This is a mix of the show audio MINUS the guest's own voice. This is done specifically to avoid the echo effect in their ear that happens due to phone / satellite / net delay getting the signal to their ear. A separate mix-minus needs to be created for each remote guest so that they can all hear each other but not themselves. If you ever see a guest on a show rip their earpiece out in the middle of their hit, it is most likely because the audio engineer sent them the wrong mix-minus and they are hearing themselves on a delay. In a show with many remote guests, its easy to cross up which line is going to which guest. It is also usually a VERY simple fix for the engineer and SHOULD be caught before the guest goes on-air. If the producers are competent, they try to get their guests set up in the commercial break and do a comms check to make sure everybody can talk and hear each other correctly. Sometimes guests sit down seconds to their air time and you've just gotta wing it. The anchors in the studio typically hear the entire mix because the proximity to the audio gear allows for near zero delay/latency for them. EDIT: just realized this doesn't really answer the question posed originally about WHY hearing the echo messes with your ability to talk and think. This was more an interesting side note to it. Hope thats ok!",
"I've done a fair bit of public speaking, and the fucked up thing is that no one warns you about that kind of thing. The first time I went up on stage I had a solid 15 seconds of looking like a moron because I'd start speaking and shut down. I was able to power through it, but it wasn't as graceful as it otherwise might have been, most people just thought it was stage fright, which is embarrassing in it's own stupid way.",
"This is called the stenger phenomenon, and it’s used in audiology if you suspect malingering - someone claiming to have worse hearing than they do. You have them read a passage, and play back their voice with a delay at a volume they shouldn’t be able to hear it at if they’re being honest with their other tests, and watch for them to stumble.",
"Not an answer, but another thing to crash your brain: apparently hearing yourself speak with a few seconds of delay can fix stuttering.",
"This is also the reason referees tend to talk in short snippets with pauses, they’re waiting until after they finish hearing each bit through the speakers before they continue talking.",
"I had this with WebEx for a bit when we first adopted it at work, it made it so difficult to speak I ended up taking my headset off while speaking until I got it sorted. My poor brain just couldn’t cope.",
"Some interesting answers here but I think the answer is very simply this: you're not expecting it. & #x200B; 99% of your life when you speak you don't hear your words repeated back to you. When you do it's always a fantastically strange surprise, so it's all your brain can focus on. Not to mention, it's like having someone interrupt you and talk over you for the entire time you're talking. Again, 99% of your life, you're not talking over people, not only because it's rude but it sounds horrendous. & #x200B; But, once you're expecting it, it's really not all that difficult to tune it out, you just have to try. Concentration is a powerful thing, you can remove concentration from your hearing and point it at the words you're saying, and tune it out, simply as that. It'll take some practice if you're not used to it, but I promise it's a skill you can learn. Next time it happens to you, treat it like an opportunity to practice that skill, to focus on what you want to say without needing to listen to what's being repeated back to you.",
"I just can't stand hearing my voice in general so when it's delayed it make my brain fry and cringe together",
"Can someone explain the question? In what scenario would you hear yourself with a delay? How is that even possible",
"My voice in my head sounds nothing like my voice in real life so when I get that delay thing it just feels like my brother is hiding somewhere out of sight copying everything I say.",
"Fun fact, speaking while hearing your voice with a delay is sometimes used as therapy for people with stuttering problems. John Glenn's wife had a lifelong stuttering problem, but when she was middle-aged, she starting taking delayed vocal feedback therapy. John Glenn practically cried when his wife called him one day, and told him about her day by speaking slowly, but without stuttering once.",
"It’s because you’re not just hearing yourself on a delay. You’re also hearing yourself several seconds in the future because your brain is working out how to make the sounds you want to make to make sense, and you’re hearing yourself in the moment you’re speaking because your brain is making physical adjustments as you go. Adding that extra voice layer not only sounds alien to you, but it also adds an extra speech layer that you’re pre programmed to pay attention to because it’s recognized by your brain as part of you, but coming from an outside source. That, and studies show that most people can only pay attention to two different voices at once. What trips you up exactly is a bit complex, but it’s more than likely a combination of the doubling of your real-time voice, and the fact that your brain is having to process three strands of human speech at once.",
"I don’t get it, when does this happen?",
"This doesn't work on me. Am I broken?",
"Doesnt a slight delay in playback actually help people with a stutter to talk more clearly?",
"Better yet anyone know how to fix this when you call someone and you have this echo?",
"You know what is even weirder? There is one group of people this does not happen to when playing their own speech back: those that stutter. Even weirder, is that this will [fix the stutter]( URL_0 ).",
"Former FOH engineer here. It actually starts at around 110msec for most males, and peaks about 200msec. It is called delayed auditory feedback. Most females are not affected at all, perhaps due to females being better at multitasking. (My thoughts). Ironically it helps some stutterers.",
"As a guitar player who's tried at home recording, latency causes the exact same issue. My rhythm falls apart. Tempo all over the place, like that old wobbly record player effect. But, if I can't hear any playback at all, I can play just fine. It's almost definitely because the brain is always trying to adjust, so delayed input translates into delayed output as well to compensate, but that delayed output contradicts what the brain thinks it should be doing.",
"I remember reading a post on this before on reddit, the explanation was your voice when you hear it, causes your own inner vibrations, you have bass in your voice, etc., when that leaves, everyone else isn't hearing all the extras vocal build, it's like when you hum, the hum sounds really prominent to you but just annoying and small to others, proxmity, bones, mass etc. -- and when we hear our voice back, it sounds puny or weird to us and we don't like it -- so hearing a delay of YOU really messes you up",
"There are areas of the brain that process the intent to speak, the physical action of speaking, and we listen to ourselves and process errors. It’s how we learn to speak and in some ways similar to how we learn to move. When you’re brain is used to hearing you speak “correctly” and all of the sudden it’s hearing the absolute wrong noises come out, this is similar to some aphasias after a stroke. Your brain is telling your mouth to make a noise but is hearing the wrong noise come out, and as it tries to correct it, you sound ridiculous."
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mhruie | Why do phones have a camera bump? Is it a hard problem to solve? | Technology | explainlikeimfive | {
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"There are fundamental physical limits on image quality with miniscule lenses and sensors, so we can't just shrink them down and improve our lens/sensor tech - unfortunately physics doesn't allow that. So for good image quality, especially in low light, we have to make the sensor and lens a certain size. For a given lens size & sensor size, there is a practical limit to how thin you can make the arrangement based on how quickly you can bend light using glass to focus it on to the sensor. We could make thinner cameras if we could find better optical materials (we would need transparent materials that can bend light more). Things like diamond or moissanite are incredible at bending light, unfortunately they have other undesirable optical and physical properties which makes them poor choices in lenses. Sapphire could potentially be used, but it's only very slightly better than the best glasses.",
"Because phone manufactures want to have good cameras and thin phones, and good cameras require larger sensors and larger lenses, which don’t really fit in the thin body of the phone, so they make a bump If manufactures didn’t care about being that thin, they could easily put a larger battery and bring the phone thickness up to the camera bump, but they don’t want to do it"
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mhs69m | How do square rigged ships sail in upwind? Can they at all? | I understand the basic concept for sailboats as the sail acts as an airfoil much like an airplane wing generating lift when air flows over it. But with square sails I can't grasp how ships that had them ever got from point A to point B without always relying on downwind to move forward. | Physics | explainlikeimfive | {
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"It is called tacking, you can alter how the sails \"catch\" the wind, so can push you from side to side rather than in a single direction Sails actually work best when the wind is on the \"quarter\" rather than directly behind them so all the sails are being pushed. By tacking you can slowly in general head into the general wind direction, but never moving directly into the wind.",
"If there isn't enough wind to tack, the ships would \"wear\". It's like turnung left three times to go right."
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mhscc8 | What happens biologically when someone has auditory hallucinations? | Asking from personal experiences of it. | Biology | explainlikeimfive | {
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"Basically, when you hear, see or otherwise sense something your brain receives a signal from your ears/eyes/whatever, analyzes it and makes a conclusion like \"Oh, it's someone saying hello\". But the brain is a very complex and convoluted system with many ways for things to go wrong. If something jams somewhere, it can mistake a piece of memory or even imaginary sound for a real one or come to a wrong conclusion even with the correct input. Many types of hallucinations exist, ranging from mild things that can occur even in a healthy brain to severe cases where a person is practically living in a fever dream unable to distinquish it from reality."
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mhstd4 | If some animals can photosynthesise, would it be possible to add it to humans? To stand in some sunlight and get energy to work out? | Or being as it's a sugar right, would I just become diabetic if I wasn't working out constantly? | Biology | explainlikeimfive | {
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"The energy required to keep a human going is far more than photosynthesis could provide you would need a surface area similar to that of a small tree.",
"If you take a broad view of photosynthesis as not just making energy, but making nutrients, then humans already do something similar. Our skin converts cholesterol into vitamin D using sunlight.",
"Photosynthesis, even under ideal conditions, would produce less than 10% the energy a human needs to survive (I can go through the maths if you want). But the cost of being photosynthetic is high because you need the appropriate cell structure which animals don’t have. While it may not be technically impossible for animals to have such an ability, the cost to benefit ratio simply isn’t there. It’s much more effective to use that energy and time building the photosynthesis cells to instead make bigger muscles so you can catch more food/run away from predators for example. There is a reason plants don’t move around much.",
"First of all, [photosynthesis]( URL_0 ) USES sun energy to force water and carbon dioxide to recombine into sugar, which is then combined into [cellulose]( URL_1 ) which forms the body of the plant. It doesn't produce energy for the plant, it consumes energy to create material (from water and air) to grow the plant. We actually do the opposite of photosynthesis. We eat the sugars (plants), and our cells BURN the sugars with the oxygen that we breathe, producing carbon dioxide and water, and a lot of energy. We do the exact opposite reaction to photosynthesis. The carbon dioxide and water get recycled, from the atmosphere to plants to animals to the atmosphere to plants again. It's a cycle. In any case, you get a lot of energy from food + oxygen, a lot more than you would get if your skin surface was photosynthetic. Gasoline engines get a lot of energy out of burning gasoline; in order to get that same energy from sunlight (with solar panels), you'd have to have a solar panel 30 m x 30 m (100 ft x 100 ft), the size of someone's yard, basically. To get the same energy as we get from food, we'd likely have to have a tree's branches and leaves (I'm not going to do the math)."
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mhsw8f | How do scalper bots buying electronics get past the “are you a robot” check? | I basically read an article explaining how scalpers (people buying up stock and selling them at prices only the foolish and desperate would allow) use bots to buy up stock? But on most online stores I shop at there are bot checkers, so how do they get around that? | Other | explainlikeimfive | {
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"There are services that allow you to send captchas to real humans elsewhere and have them do it and send the results back to the bot to put in. Or there are other bots trained to defeat captcha and can be accessed by the scalper bots to fill it out in a fraction of a second (or purposefully longer depending on what the captcha system looks for)"
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mhsxep | If fear is a response to a perceived danger, why do humans and other animals sometimes freeze up or faint when afraid, becoming more vulnerable? | As I understand it, fear is essentially a warning system to alert you that you are in danger, and encourage you to take action (the Fight or Flight reflex). That being the case, why is it so common for people to freeze up, faint, or become catatonic, when these responses prevent them from reacting to the threat, and places them in more danger? Same applies to other animals. Fainting Goats, obviously, rabbits will sometimes suffer fatal heart attacks in response to fear, etc. | Biology | explainlikeimfive | {
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"The majority flee. A minority freeze in place. The herd survives just fine overall. It's kind of a variant on \"I don't have to outrun the bear, I just have to outrun you\"",
"Freezing in place is often a good survival strategy. You may have noticed a predator, but that doesn't mean it has noticed you. Taking off would be very conspicuous, and the predator would *definitely* notice you, and may chase you. If you stay very still, it may wander past you. Fainting is a side effect and not a desirable effect. When your body reacts strongly to fear, it dumps a load of chemicals into your blood, increasing your heart rate, blood pressure, glucose levels in your blood, etc. Blood is often drawn *away* from your brain so that your muscles can get more energy and oxygen. If your response is too strong, your heart beats to erratically and suddenly your brain isn't getting enough oxygen. Maybe the \"freeze\" part is a bit too strong and your breath catches, too. You try to move too quickly and your body just can't keep up, so you pass out. It isn't *meant* to happen, but sometimes it does. Our ancestors that didn't have a strong enough fear response died as a result. Too strong a response may also get you killed, but there will always be random variation so that some people just react more strongly than would otherwise be safe or healthy.",
"I’d like to know more about this too. I always thought that it’s just our lizard brains backfiring in today’s changed environment. I used to struggle learning to backflip and to this day I think the only thing holding me back was fear. After I froze mid-air a few times and landed on my neck, I started to be afraid of being afraid. It was very bizarre realizing your fear could’ve killed you, but when you think about it, we weren’t made to backflip around.",
"Some predators won't actually attack prey which has fallen over that they didn't kill or attack themselves.",
"I've come to learn this through my own mental health struggles. A fear stimuli leading to panic which leads to action to stop whatever is causing the fear - this is what you'd think normally happens. But when the fear stimuli perceived by the brain is evaluated as having no escape, like let's say an oncoming car or in another case being in a traumatic situation, the body instead goes numb or dissociated or faints as a way to reduce the pain of what it perceives as not just something scary but certain death. For example, if a lion was to walk into your room rn instead of acting you'd freeze up. It's just the brain has evaluated that it's going to go through extreme pain and death so it numbs your senses / makes you faint as a way of coping."
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mhsxev | Digital Audio Fundamentals | Other | explainlikeimfive | {
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"Sound is a wave, think of that sine wave you see on the monitors in movies. We convert that to digital by taking vertical slices at intervals on the time scale, checking the value at each point. Sample rate is how many slices we take per second. The CD sample rate is 44,100 per second, although other formats go up to 96,000 per second. This is thought to be enough that your ears can't discern sampled audio from the original. Now that we have a slice, how fine detail does it have? Do we use 0-100 to represent every value under that curve, no matter how high it is? No, that wouldn't store enough information, meaning the dynamic range of the sound would be too low, so it would sound very bad. A CD uses 16 bits, or 16,556 different values to give us a good dynamic range. Higher quality audio these days uses 24 bits, or over 16 million, to give better dynamic range."
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mht11t | Why do people only sneeze when awake? | Biology | explainlikeimfive | {
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"During REM sleep (the phase where dreams take place), your muscles are paralysed so that you don’t thrash around and hurt yourself. This paralysis extends to reflex muscle contractions, so you can’t sneeze while you are dreaming. In non-REM sleep your muscles are free to move again but the trigeminal motor neurones responsible for triggering a sneeze are still suppressed. It is just about possible to sneeze during this non-REM sleep, but the exertion will normally wake you up."
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mhtoub | Why does increase in binding energy lead to release of energy? | Please explain in the easiest way, I’m very dumb lol | Physics | explainlikeimfive | {
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"I don't think it does. Binding energy is the amount of energy needed to separate a particle from a system, like releasing an electron bound to an atom. So the larger the binding energy, the more energy you need to put in to get that electron out. If you put exactly the binding energy into that electron then it uses all of that energy to escape the atom and leaves with no extra energy. If the binding energy is 5eV and you put 8eV into that electron, it uses 5eV to escape the atom and leaves with the left over 3eV."
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mhu81x | Why do eyes turn red? | Sometimes they just turn real red and I can see the nerves but at other times I cannot. Why does this happen? | Biology | explainlikeimfive | {
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"your eyes are filled with a lot of tiny veins (capilaries). they are almost invisible most of the time. But when your eyes are irritated, when you consume a vasodilator (a molecule that makes your sphincters open) molecule or when you are forcing the focus on something \"hard\" to focus on, your eyes needs/have more blood, making your veins bigger and you can see them.",
"You cannot see the optical nerve in your own eyes (and it would be a cause for concern if you did). If your eyes are red that means the capillaries that provide blood to it are swollen, either due to inflammation, or just irritation. Your eye muscles could be strained from working too hard, or there’s a piece of dust that the eye is working extra hard to remove by blinking, tearing and such."
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mhukxs | What was gold replaced by FIAT money? | Moreover, I also want to understand before the FIAT money fiasco why did only gold achieve an standard for barter. Why did not any other metal met that standard? | Economics | explainlikeimfive | {
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"Fixing the value of money to the price of a commodity which has, normally, very stable prices (due to limited production and demand for non-monetary purposes), effectively ensures stable prices. Gold fit those needs better than most commodities. However, it leaves governments with very limited capability to expand or contract the money supply in response to economic conditions. The \"fiat money fiasco\" has allowed central banks to respond to downturns and are a big reason why the financial crisis and covid downturns didn't look more like the great depression. The big downside of a fiat currency is if the central bank loses its credibility to set inflation targets. For example, see Turkey, where the president, who believes that low interest rates reduce inflation, has repeatedly fired heads of the central bank and the market largely believes (and acts as if) inflation will be high regardless of what the government does. When a central bank is independent and the market believes them when they say \"monetary policy will aim for inflation of x%\" then inflation remains low.",
"Looking historically, all sorts of commodities have been used for trade between nations or groups, often simply as units of account (I'll trade you \"20 cows\" but really I give you the equivalent in iron and you'll pay me back in some form in the future.) Silver and gold are the most common, for various reasons. If you have the idea that before the 20th century money was always backed by gold (or silver) and that now we have these messed up fiat currencies, this is quite wrong. The origins of money are kind of complex, but it seems that it originates just as much in debt and trust as in the use of precious commodities. And don't forget that trust is required for metallic standards too - you still have to trust that a central bank will meet its promises, that it won't devalue (or revalue) its currency, or anything like that. It's not like being on the gold standard is a law of nature and once you're on it it can't be changed."
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mhur9j | where do the electrons in electricity come from and how does that not wreck up other atoms that I assume need those electrons | For example, I was listening to a podcast about hydropower, and the mentioned that the water current does what it does, and shakes these electrons free and that creates electricity, but do the h2o molecules lose an electron, or are there just a ton of free roaming electrons out I'm the world. I have no clue how it all works, do maybe my assumptions are all wrong, Thanks in advance! | Other | explainlikeimfive | {
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"No electrons in H2O molecules get moved anywhere. Water turns turbines (in hydro and pretty much all but solar plants); turbines move rotors of conducting materials (say copper wire) inside a magnetic field. This in turn shakes the electrons in the wires one way and the other; the rotors are connected to the transmission wire and that little movement is the electricity we consume.",
"The water doesn't lose electrons. It turns a magnet inside a coil of wire that pulls loosely held electronics along and induces a current. As it pushes electrons out they travel in a circuit feeding back into where the other electrons are pulled from. The simplest is direct current. The electrons flow out the negative and get pulled in the positive. Alternating current pushes and pulls. With that you can use the earth as part of the circuit. Metals don't hold electrons very tightly. They can flow around. That makes them good conductors. Water is not a good conductor, but if you add some impurities like sodium (a metal) in there it will let the electrons flow. You can get imbalances, but those cause sparks and static that get satisfied from around the environment."
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mhusgl | The US National debt is reaching $30 Trillion. Why does this matter and how can it hurt us? | Economics | explainlikeimfive | {
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"text": [
"The raw number on the debt, strictly speaking, is not important, or at least is kind of meaningless without context; what does matter are things like debt-to-gdp, or the ratio of the amount of debt against the actual amount of economic activity going on. In the US's case, debt-to-GDP bounces around between 100% and 107%, which is high but not really that unusual (greater Euro area is between 90% and 100%). However, the more important thing to understand is that the US economy is not like other economies because it's simply so much larger than everything else, thus trying to compare the US to other nations in this regard is not exactly useful. As a result, not only does the rest of the world not really care about the US debt being \"high,\" but they ***want*** US debt to be high, because that means more extremely safe debt for them to buy, and which they turn around and use to underpin their own central banks. Put another way, if the US starts having issues in paying that debt, literally every other country on the face of the Earth (including the highly disconnected nations like North Korea) will have a bigger problem than the US will, entirely because there is no alternative for the global economy than US dollars and US debt-based financial instruments. There also isn't about to be an alternative for US debt because every other major economy has pretty serious issues, hence why 90-95% of international trade ends up involving dollars, even though the US isn't directly involved in the overwhelming majority of that trade.",
"The cost of debt changes over time. Today, interest rates are at record lows and the US can afford high debt. Interest rates are low because inflation in the US is low and investors don't have other equally-safe places to put their money. All those things can change. In the 1980s, the interest rate paid by the US was 10 times higher than it is today. If poor government policies were to return to those rates, taxes would have to increase dramatically to pay the interest in the debt.",
"The debt payments are what can “hurt” us. Just like you make a regular payment on your car loan, student loans, or mortgage, the government has to make regular payments on its debts. And just like your loans, money spent paying your debt cannot be spent elsewhere. It is worth noting though that not all debt is bad. Just like doctors take on A LOT of debt to go through medical school, but end up with very high salaries (and an overall net increase in take home pay, even after making their debt payments), a country can use debt in ways to increase the overall wealth of a country. The easiest example (and probably least controversial) is during an economic recession. During a recession, there is high unemployment and therefore less consumer spending (which leads to greater unemployment, in a vicious cycle). Since governments rely heavily on income and sales tax, the government also brings in less revenue. However, it is generally accepted that the best course of action is for the government to increase spending (through additional debt) in order to end the recession as quickly as possible. This is all to say that it can get pretty complicated. Just like in your own life, some debt is good and other debt is bad."
],
"score": [
12,
6,
4
],
"text_urls": [
[],
[],
[]
]
} | [
"url"
]
| [
"url"
]
|
|
mhuy5s | How are planets formed? | I understand that planets are essentially space rock that got together and made what we know today as planets, I’m simplifying this a lot but let’s go with it. What I want to know is how those space rocks are formed and then put together to make planets? Where did the rock come from? Is it elements clashing together millions of times over until they form what we know today as space rocks? | Physics | explainlikeimfive | {
"a_id": [
"gt1010y",
"gt10553"
],
"text": [
"Planets form in a region of space with the right sort of raw material. As that material collects, due to gravity, forming a star, the remaining material which has enough velocity collects in orbit around the star. After that's it's bumping into each other until everything is synchronized into a plane, then a ring, then a ball due to self gravity.",
"Our star system is a second-generation one. That means that whatever is in it used to be part of other stars before that. When those previous stars blew up, they formed interstellar clouds of matter. Some part of such a cloud happened to condense into our solar system. And yes, small pieces of stuff lumped together randomly until they formed asteroids, and then planets."
],
"score": [
4,
3
],
"text_urls": [
[],
[]
]
} | [
"url"
]
| [
"url"
]
|
mhvjje | Why do we need to distinguish between rational and irrational numbers? What's the importance of knowing where they fall between the two? | Mathematics | explainlikeimfive | {
"a_id": [
"gt13pvi",
"gt1703z"
],
"text": [
"Because, you can develop a definite value for a rational number, it is exact. Irrational numbers are approximations of the value, the more precise you get with it the closer you are to the true value, but you will never quite reach it. You can take pi to 25 quintillion decimal places, but you still won't have its exact value.",
"same reason you need to distinguish between sharks and piranhas. it probably wont matter to you if you're not doing anything in a related field, but when you do the differences are massive and it is important. rational numbers are all number you can write as a fraction (you could write 0.153 as 153/1000, so this includes all ending decimal numbers) while irrational are those like Pi where that isn't possible."
],
"score": [
8,
3
],
"text_urls": [
[],
[]
]
} | [
"url"
]
| [
"url"
]
|
|
mhvl69 | what does my ISP know about me ?? | and is there any way that i could minimize its "knowledge"? | Technology | explainlikeimfive | {
"a_id": [
"gt14ezf",
"gt13od0"
],
"text": [
"In this day and age, here's what your ISP can see. First, they can see your DNS requests. When you access URL_0 , you have to make a request to know which IP Address URL_0 is. DNS is a plain-text protocol, so your ISP sees all that. Second, they see the amount of traffic coming out of your modem, and the destination IP/Port of that traffic. If they know you access an IP associated with URL_1 on port 443 and download 800TB of traffic from it each day, they know you're downloading a lot of data via HTTPS from URL_1 , even if they can't see exactly what it is. Third, for any website that doesn't use HTTPS and just uses HTTP, they can see everything you access on it. They can see the specific page you're requesting, they can see anything you enter in a form and submit. As for other comments who say \"Just use a VPN\" -- all you do is move the problem upstream to the VPN. At some point your traffic goes over the public Internet without any additional encryption beyond the protocol (i.e. HTTPS). You're just changing who you decide to trust.",
"If you don't use a VPN all the time, your ISP knows everything you do on the Internet. If you want to minimize this, you should use a VPN. Then your VPN vendor will know a lot about you. Maybe it would be better not to do what you're doing online??"
],
"score": [
7,
3
],
"text_urls": [
[
"reddit.com",
"cornhub.com"
],
[]
]
} | [
"url"
]
| [
"url"
]
|
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