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3joj9q | why are chinatowns celebrated in american cities as tourist destinations? what's the cultural significance compared to say a braziltown? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3joj9q/eli5_why_are_chinatowns_celebrated_in_american/ | {
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"We do not have a lot of Brazilian immigrants, and those that we do have are not extremely likely to congregate. \n\nThat said if a Braziltown did form it would not have the same draw as a Chinatown because it is not culturally different enough. Brazil is a former Portuguese colony and much if not most of their culture has developed out of its European roots, just like the US has. Chinatowns do not have European roots, they are vastly different from the culture around them and that difference is what is entertaining and what attracts people. "
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2sfidx | why does the sound of a knife/fork screeching on a dinner plate sound so terrible to us humans? | I almost want to cry after having heard it - but why? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2sfidx/eli5why_does_the_sound_of_a_knifefork_screeching/ | {
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"One theory is like [nails on a chalkboard](_URL_0_) it resembles a monkey screeching where you need to get goosebumps (puff up and look big) and get outta dodge.",
"If you've got an hour to kill, check out this episode of Radio Lab (more specifically the second half). They talk about sound and speech in terms of music, and then they get scientific about why certain sounds are \"painful\" to hear and others are pleasant.:\n_URL_0_\n\nAlso check out some of their other episodes. Radiolab is an awesome place to go if you want to pique your curiosity.",
"The two main theories are:\n1) The sound reminds us of the sounds/calls a lot of primates and apes make when they are scared, in stress or alarmed. It could be hardcoded in our DNA to react to this sound with negative emotion, stress and fear\n2) The typical frequencies produced are the same that can give rise to resonance in the ear canal, thereby amplifying the sound to unpleasant or even painful levels.",
"According to [this article](_URL_0_), the frequency range between 2 kHz and 4kHz is the range that our ears amplify the most. Removing the noise in these ranges was rated to most effectively help with the 'annoyingness' of the noise, even more so than the higher frequencies.\n\nAs well, the 'roughness' of the noise, or how often it changes pitch, also affects how painful the noise can be. Sounds fluctuating between 20 and 200 kHz are the 'roughest' noises.\n\nHowever, the 'most annoying noise' is a knife on a glass bottle, [according to the Journal of Neuroscience](_URL_2_), and you can listen to the top 5 annoying noises [here](_URL_1_), if you're interested. :-)"
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14u6p4 | how do wireless providers make money from mvnos? | Wouldn't creating competition that undersells your own same product while also using your own network be bad for business? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/14u6p4/eli5_how_do_wireless_providers_make_money_from/ | {
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"MVNO's are based on the internal accounting principle that every cost shall be applied to the business unit that consumes the good or service. \n\nBasically, think of Sprint (which is the major network company that serves MVNO's) as two companies: a wireless network operator, and a wireless service retailer. The network operator builds, maintains and operates the network. The wireless service retailer buys service from the network operator, and resells it to retail customers in the form of cell phone contracts. Using the aforementioned accounting principle, the network company 'buys' the network (by building it) and 'manufactures' wireless service; the retail company buys finished wireless service from the network and resells it to consumers. It's similar to how car manufacturers work - Ford builds a car, then sells it to a dealer wholesale, who then sells it to a consumer, retail. Ford makes a profit when they sell it to the dealer, and the dealer makes a profit when they sell it to the consumer. In actuality, the dealer's profit on the sale of a single car is often larger than Ford's profit on the same single car is, but Ford sells millions of cars, whereas the dealer sells maybe a few hundred. \n\nThe MVNO goes to Sprint ant says \"I can buy the wireless service from your network division for the same amount that your internal retail division does, but I can add value (lower cost, better service, different phones, different payment methods, etc) that your retail division can't or won't.\"\n\nSprint likes this, because it helps earn extra revenue for the network, without doing things it might not like to do (eg, cutting prices, or changing policies that discriminate against lower-income consumers). \n\nSo your question starts from a few flawed premises:\n\n > creating competition\n\nMost of the MVNO's on Sprint's network (for example) don't compete with Sprint (they are going after a different market segment - usually pay-as-you-go customers who don't or can't get contracts). \n\n > undersells your own same product\n\nThey are underselling the retail division, but they pay at least the same rates as the retail division does for network access - and potentially more. In addition, the MVNO's probably have to make volume commitments (ie, guarantee that they will buy $X Million in service per annum) which is great for your balance sheet because big commitments are cheaper than a bunch of small ones. \n\n > using your own network be bad for business?\n\nFrom the perspective of the network company it isn't, because they are getting paid more money for the same network service (ie, they have to pay for the network regardless of how many users are on it, by getting more users they are able to spread the cost of maintaining the network over more users and thus increase profitability). \n\nIt's actually a kind of 'best of both world's' mode. \n\nVertical integration actually sucks for shareholders. Wall Street and banks like it, but in the long run it destroys the company through stagnation. ",
"The thought is that MVNOs can reach additional customers that the wireless providers wouldn't have been able to acquire by themselves.\n\nThey do this by targeting specific groups of customers (those who want pre-paid or no-contract plans), offering different phones and devices, and generally differentiating them in some way from the wireless provider.\n\nThere's definitely some cannibalism that goes on, but the hope is that the MVNOs bring in a net gain to the wireless provider.",
"It's actually a pretty clever tactic. If you were selling things, wouldn't it be great to be able to only show people your expensive items, until you were sure they weren't going to buy from those, and then (and only then), show them your less expensive items? This is basically what having MVNOs allows the providers to do.\n\nA lot of wireless customers will just go to the nearest Verizon (or AT & T or Sprint) store and sign-up for whatever plan seems the most affordable with the right features. By limiting the plans (and price points) they offer, providers can push people into buying more than they need (or paying more than they should for what they need).\n\nDoing that causes a lot of people to say, \"Never mind, I guess I don't need a cell phone.\" By allowing MVNOs to exist, the providers can \"recapture\" these lost customers. Getting a customer that pays less than you want is always better than not getting them at all.\n\nIt took me a looong time to get a cell phone. I wanted a cell phone for *very* occasional use. Like, I might make a 5 minute call once a week or so. I wasn't willing to pay more than about $10/month for that, though. None of the providers had anything for me. About two years ago I discovered a Sprint MVNO that had what I was looking for. I hadn't known about MVNOs before that time, or I would have been a customer sooner. Because of that MVNO, Sprint got some of my money rather than none of it. So it was a win for Sprint (and me).\n\nThe providers need to be careful (and they are!) that they don't lose too many customers to the MVNOs. When they balance it right, they get more profit than they would if they just made a perfect-fit plan for every possible customer themselves."
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1j4vab | how do the highs differ and compare to each other in psychedelic/hardcore drugs like ecstasy, mdma, shrooms, dmt, coke, heroin etc..? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1j4vab/how_do_the_highs_differ_and_compare_to_each_other/ | {
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"Well, MDMA and ecstasy are the same thing, and I have not taken that. \n\nCoke is a stimulant so the high is gives you a feeling of alertness and euphoria. It will make you boring to others because all you want is more coke. \n\nHeroin is an opiate, so the high is sedate, warm and dreamy. \n\nMushrooms are hallucinogenic and cause possible hallucinations, and thoughts and conversations feel deep and meaningful, which may or may not be actually true. :) \n\n",
"Uh... you want *this* explained in terms a five year old would understand?"
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15rzmx | how does dairy pricing work, and why do most coupons exclude dairy? | I work at a grocery store and have always wondered. I just assumed it was some kind of dairy mafia or a strong dairy lobby. Then I saw that the latest "Fiscal Cliff Deal" was to hold down the price of milk, and I was all kinds of confused. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/15rzmx/eli5_how_does_dairy_pricing_work_and_why_do_most/ | {
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"The milk prices are set by the Farm Bill, which requires milk prices to stay low. The Farm Bill would have expired along with a number of other bills. The collective expiration and the results those expiring bills would have effects on the economy as a result of changes in spending and taxation that is all called the fiscal cliff. The reason the Farm Bill is included is that it deals with more than just the price of milk, it deals with the taxation of farm goods, disaster aid for farmers, subsidies for farming, and even food stamps. \n\nIf the Farm Bill had expired, the milk prices would have instead been regulated by another bill passed in 1949 that dealt with milk prices. However, this other law would lead to much higher prices, maybe two or three times higher, because it would have changed the way milk is bought from farmers and sold to consumers. \n\nThis increase in milk price would have been good for some milk farmers, but not good for consumers or anyone trying to sell milk competitively overseas. \n"
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5ma4n5 | ; why does traffic construction, (like an intersection), seem to take so much longer than other construction projects of equivalent size (like a medium sized building)? there seems to be huge stretches of time where little to know progress is made. what's going on? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5ma4n5/eli5_why_does_traffic_construction_like_an/ | {
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"Just for starters: There's a ton of ancient and delicate infrastructure under any urban street and there aren't great records of what-all is down there (and you can't see it until you've put a backhoe through it.)\n\nSome of that stuff is natural gas lines -measure thrice, cut once.\n\nIf you built your medium-sized building underground you would be comparing apples to apples.\n\n",
"There's also the matter of money and resources. Most streets and roads are publicly funded whereas most buildings are private, with additional dollars associated to completing it on time and on budget. There's more money to be made in the commercial sector and a larger pool of subcontractors to choose from, unlike in municipal projects where you can only choose workers that have already been certified to work for the state/county. It's also a different skill-set. My brother who was a roofer for hotels could switch to residential without much trouble. But the electricians/ plumbers who work on municipal projects usually have much more training. Many times if you see the same orange cones up for a long period of time its because they're waiting on someone specialized enough to do the work or certify the work was done correctly. \n\nSource: friends and family who work private sector construction. Please correct any misstatements on the public side. ",
"To be fair, one big reason is actually just incentive, it's easy to find other ways to get around when a road is under construction, so not as much money is poured into it. Faster completion of buildings = faster the money comes in. I live in Taiwan, where the same length of road can be patched in a day compared to like a week in Canada (sorry Canadians, lived there once, only reference I got)\n\nThere's also different reasons depending on the road location. Since digging up a road is inconvenient, once it is done, much of what is under the road is also redone at the same time, and each pipe, phone line, electricity, sewers and such are from different companies, so they also have to take the time coordinate.\n\nAlso, for roads where there's empty space underneath (such as for metro) the road is laid down and then taken up again, slightly less thicker each time. This way it compresses the layers each time and makes it much more resilient to pressure.",
"1. Utilities in the work area need to be located by hand excavation (that's the law)\n\n2. Utility relocation, protection, and support can be tedious and time consuming. Gas, steam, and electric are dangerous to relocate, therefore every precaution is taken. Telecom relocation is time consuming due to copper and fiber splicing. Water may only be able to be taken out of service at certain times. Sewer is typically fairly deep and time consuming to shore up trenches.\n\n3. Materials cannot often be brought in and stock piled due to space restrictions. Depending on where you're working, they might not allow you to store any materials on site. This means everything has to be brought in when it's needed, even the excavation equipment might need to be removed and delivered daily.\n\n4. Truck loads of material brought in (fill, concrete, pipe) have to be ordered and picked up or scheduled for delivery. Example: you order a concrete truck and it sits in a traffic jam, it gets there late. If it's been spinning in the drum too long, it's no longer any good and the load is rejected. Now you wait for another load to come.\n\n5. Work permits typically stipulate the times you can work. I've gotten permits where we could only work 10am - 2pm, Monday - Thursday or 8am - 6pm Weekends only. Subtract at least an hour of productivity from that for opening up the job site and cleaning up.\n\n6. Unforeseen circumstances cause a lot of delay (inadequate design on the engineer's part, poor planning on the contractor's part, utilities not known about until the tooth of a machine bucket ripped through it.)\n\nThis is not to say that some of this doesn't happen in building construction, it does, but their job sites are usually less constrained than road work.\n\nSource: Civil Engineer, worked construction in NYC for 10 years.",
"/u/Dennaldo has the most comprehensive answer, but didn't touch on crew scheduling -- maybe it wasn't an issue in NYC!\n\nYou or your prime contractor may or may not have all the various crews that a project needs, available at the drop of a hat -- many construction projects are scheduled a year in advance. The sewer-pipe crew, for example, might be multitasking several road projects at once, since each of them doesn't need a full-time sewer crew. But, they may be working on project 17 on the other side of town for a couple more days when your project is ready for them again. So, everybody shifts to something else for a while.\n\nThe worst thing to have happen is to have a crew show up on their scheduled-weeks-in-advance day, and **you're not ready** -- your project has been delayed by weather, or a previous task isn't quite ready yet. So, to keep that crew busy, they get sent (out of order, so to speak) to a different project, and YOU WAIT.\n\nTo accomodate this, your project scheduler may allocate a week for three days worth of work now and then, so that a previous crew can lose a day without impacting the rest of the project. That's another reason why it may look like nothing is happening -- scheduled slack that turned out not to be needed."
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34c5kk | how did evolution make this bug look like a leaf? | [The bug in question](_URL_0_) | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/34c5kk/eli5_how_did_evolution_make_this_bug_look_like_a/ | {
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"Its ancestors that didn't look like leaves were killed or failed to reproduce. Its ancestors that did look like leaves survived long enough to pass on their genes and produce offspring that also look like leaves .",
"Evolution isn't intelligent, it didn't design that bug to look like a leaf.\n\nRandomly, a bug looked kind of like a leaf. Because of this, he was less likely to be eaten, so he passed on his genes. He created a thousand children that all looked kind of like leaves and they had more children and the gene spread, and then as two leaf-like bugs mated, the effects became more pronounced. Creating bugs that look nigh identical to leaves.",
"Very, very slowly.\n\n10 million years ago, this bug's ancestors may have just looked something like little green grasshoppers. Then, one was born that had a tiny mutation - the edges of his thorax (butt) weren't rounded, but were instead sort of jagged. It didn't change much about his life, but maybe it saved his life from one bird that didn't see him. His kids had that sort-of-jagged butt too, and sometimes they wouldn't get eaten and a round-butt bug next to them would be eaten, so they survived (and bred) a little more.\n\nThen one of those kids had another weird mutation - little ribs that stuck out. He and his kids had a better survival rate than anyone else. Then a kid had a mutation that made him orange - he didn't live long at all. But another kid had a mutation that made him curve this way, or made him a little more green, or a little more X, Y, Z.\n\nA few million generations later, the surviving kids have accumulated dozens of mutations that helped their ancestors survive - they finally look like a leaf, even to the best eyes of humans and hawks."
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9jxzqc | does being a bouncer or security guard exclude you from the consequences of beating someone up? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/9jxzqc/eli5_does_being_a_bouncer_or_security_guard/ | {
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"Depends on where you are, but generally the guide is 'reasonable force'. But bouncers / security guards don't have a 'get out of jail free' card.",
"They are still held accountable for their actions and the use of unnecessary force can and will be punished. Just because someone chose this profession doesn’t mean they get to roll through life giving “free beatings” without recourse.",
"Absolutely they can still be charged with battery or assault. A security guard has a somewhat easier time mounting a defense on the basis of self-defense (which, somewhat confusingly, also covers defense of others), since he has a built-in answer to the question *why didn't you just walk away from the whole situation?*\n\nBut even when they're performing their lawful duties (watching over a store, or ejecting rowdy patrons from a bar, or what have you) a guard or bouncer still has the usual responsibility to use a level of force that's appropriate to the need and situation. One of the principles here is that you can use force to *prevent* someone from committing a crime– against you or against someone else you have a duty to protect– but you can't do it to *punish* them for it."
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3ckkir | if deserts were former oceans, then what is stopping current oceans from turning into deserts? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3ckkir/eli5_if_deserts_were_former_oceans_then_what_is/ | {
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"Only that their low elevation keeps water flowing into them. If you could make the bottom rise up high enough (above sea level), an ocean area that doesn't see much rain would then be a desert.",
"A lot of the surface of the Earth was previously underwater, and many millions of years from now there will no doubt there will be dry surfaces that are today underwater. The shape of the Earth is constantly, if very slowly compared to human lifetimes, changing. \n",
"The continents consist of less dense minerals. Granite is less dense than basalt. Cool basalt will sink into lava. It is more dense. The continental minerals will stay above lava. \nWhen there is not much ice in the world the ocean levels are high producing shallow seas above the continental rocks. When ice sheets form the shallow seas become deserts as the ocean levels drop.\n\nBeyond the continental shelves the oceans are thousands of feet deep. Sea levels vary about five hundred feet depending on how much water is locked up in ice."
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391b5y | what happens if the us president goes insane and orders the military to do something unprecedentedly immoral? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/391b5y/eli5_what_happens_if_the_us_president_goes_insane/ | {
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"If the president were actually crazy, then the 25th Amendment is the plan you are looking for. The most relevant part reads:\n\n > Section 4. Whenever the Vice President and a majority of either the principal officers of the executive departments or of such other body as Congress may by law provide, transmit to the President pro tempore of the Senate and the Speaker of the House of Representatives their written declaration that the President is unable to discharge the powers and duties of his office, the Vice President shall immediately assume the powers and duties of the office as Acting President.\n\nSo, basically, the cabinet and the VP could say \"sorry, motherfucker's gone bonkers,\" and take legal power away from the president, and then undo all the orders. ",
"This has been an unresolved issue for a long time. When Abraham Lincoln was in Congress he wrote this in a letter to his law partner:\n\n\"Let me first state what I understand to be your position. It is, that if it shall become necessary, to repel invasion, the President may, without violation of the Constitution, cross the line and invade the territory of another country; and that whether such necessity exists in any given case, the President is to be the sole judge. ... But Allow the President to invade a neighboring nation, whenever he shall deem it necessary to repel an invasion, and you allow him to do so, whenever he may choose to say he deems it necessary for such purpose—and allow him to make war at pleasure. … If, to-day, he should choose to say he thinks it necessary to invade Canada, to prevent the British from invading us, how could you stop him? You may say to him, 'I see no probability of the British invading us' but he will say to you 'be silent; I see it, if you don't.'\n\n\"The provision of the Constitution giving the war-making power to Congress, was dictated, as I understand it, by the following reasons. Kings had always been involving and impoverishing their people in wars, pretending generally, if not always, that the good of the people was the object. This our Convention understood to be the most oppressive of all Kingly oppressions; and they resolved to so frame the Constitution that no one man should hold the power of bringing this oppression upon us. But your view destroys the whole matter, and places our President where kings have always stood.\""
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8q5eor | how do people swim across oceans? don't they get tired and need to rest? how do they eat, drink and sleep? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/8q5eor/eli5_how_do_people_swim_across_oceans_dont_they/ | {
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"There are support crews on boats to provide him with food and water and a place to rest. The gentleman doing it now also has a small boat that's leading him so that he doesn't go off course (his previous \"run\" was not official in the Guinness Book of World Records since he allegedly floated off course).",
"From the Wikipedia article about Benoit Lecomte: From 16 July to 25 September 1998, Lecomte undertook a swim in stages from Hyannis, Massachusetts to Quiberon, Brittany, France, including a one week stop in the Azores, a Portuguese archipelago[1].\n\nDuring his 3,716 mi (5,980 km; 3,229 nmi) 73 day journey, Lecomte was accompanied by a 40 ft (12 m) sailboat that had an electromagnetic field for 25 ft (7.6 m) to ward off sharks. He was accompanied by a crew of three aboard the sailboat, where he could rest and eat between each swimming period. Lecomte typically spent eight hours swimming each day in sessions of two to four hours.\n\nThe stated purpose of the swim was to raise money for cancer research as a tribute to his father.\n\nLecomte's claim has not been recognized by the Guinness World Records.",
"A guy who is currently crossing the Pacific from Japan to Hawaii ..swims 8 hours a day then gets on a boat, sleeps, eats, shits..and gets back in the next day."
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2e4k14 | what's the hard white stuff that builds up on your teeth, and how do i prevent it from building up? | I always have to get it picked off for at least 10 minutes whenever I go to the dentist | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2e4k14/eli5_whats_the_hard_white_stuff_that_builds_up_on/ | {
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"It's plaque, also known as calculus (unrelated to the mathematical field). This forms when you allow the normal bacteria in your mouth to build up layers of biofilm on your teeth. \n\nYou prevent it by brushing your teeth (properly and for the full two minutes or more), flossing, and rinsing with a mouthwash twice a day. To really prevent plaque, brush your teeth after meals if you can. \n\nThe dentist will still spend time cleaning your teeth even if it's aesthetically spotless because the best way to ensure dental health is to regularly detail clean the teeth with their equipment. "
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2utz46 | (i know little about business.) what would have to happen for a massive and remarkably popular company like starbucks or mcdonald's to ever go out of business? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2utz46/eli5_i_know_little_about_business_what_would_have/ | {
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"These companies are so large and resilient they probably would never go out of business unless something completely revolutionary appeared on the market that ended the need for what they provided. These corporations are deadly efficient and extremely resilient, often able to take huge losses in customers and revenue. They adapt to new trends very quickly and can dump flaming dump trucks of money into marketing and PR to promote themselves. So if you wanted to make McDonalds go out of business for example, find a way to provide good-tasting, convenient food for less than dirt cheap. Or somehow make food obsolete.",
"McDonalds has thousands of locations over dozens of countries. Even if they were found to be serving bushmeat for shits and giggles they'd still survive.",
"A couple of ways a monolithic company will go out of business come to mind. One, the government will shut them down. This may be through anti-trust laws, they may be found guilty of some egregious crime, etcetera (Ma Bell, Enron). Two, the company may decline slowly from lack of customers as public opinion shifts away or a competitor replaces it. Another, very similar reason, is their tech becoming obsolete (Kodak). Fourth, there's always the possibility that a company will attempt to branch out in a direction that's not feasible, perhaps to avoid obsolescence, and winding up deep in debt.\n\nMcDonald's/Starbucks aren't really ever going to become \"obsolete,\" they don't really rely on technology in that way, but they could be destroyed in any of the other ways. ",
"Think about Sears/KMart, JCPenny or maybe even the Office Depot/Max/Staples of the world. Although not as monolithic as a Starbucks or McDonalds, they have drastically lost business in the last decade due to being out-competed by other businesses (especially online) who can deliver the same or better products faster and cheaper. At one point, the Sears catalog was a pre-digital Amazon. They just did not change with technology, markets, and culture fast enough. I don't want to be a downer but unless some of these companies really strike it rich with an innovative new business model, they will continue to fail. Obviously the food industry is different than the examples I've listed, but competition is competition. If Starbucks and McDonalds do crumble, it will take a very, very long time and will come down to them being out-competed. In fact, McDonalds has struggled in recent months (hence the new CEO) in part due to the current preference \"fast casual\" restaurants like Chipotle that offer customization options, especially by millenials. For McDonalds to stay competitive with a more social conscious generation, they will need to adopt a model more like Chipotle. In 2008, Starbucks was really struggling with underperformance due in part to the recession but also over saturation of the market and cookie cutter storefronts, so they brought back their passionate CEO from a decade earlier who re-invigorated the brand. Who knows what Starbucks would look like today if they had not done this - maybe more like a Blockbuster. "
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2j6sx1 | why does the appendix have to be cut out because of appendicitis, why can't it just be cleaned, what exactly is causing the blockage? | I mean cleaned as in having whatever is causing blockage be removed and then being treated with antibiotic/anti-inflammatory, or whatever would be necessary?
I'm asking because right I have been getting appendicitis symptoms, which have been progressively getting worse the past week. I'm not too thrilled to be really cut open. So why can't something be done differently?
EDIT: I appreciate the concerns. But I cannot depend on medical advice here. I will be seeing a doctor tomorrow. Still waiting for a satisfactory explanation. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2j6sx1/eli5_why_does_the_appendix_have_to_be_cut_out/ | {
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"Go to the doctor right away. The appendix will grow and grow until it bursts, and you develop a severe immune response. There is not enough blood penetration to the appendix, and it is filled with so much crap that you would need to manually clean it out. That's a lot harder than just taking it out, and never having to worry about it again. \n\nYou should be posting this from a hospital. \n\nHave you been diagnosed with appendicitis by a doctor or yourself?",
"The appendix is a vestigial organ. So far as we can tell, it once had a use, but no longer does. For some reason, the evolutionary process never got rid of it. Because it doesn't really serve a purpose, it's a lot easier to just go in and cut it out, than to try and fight off an infection.\n\nBut if you've been having symptoms for this long, get to a doctor! It's going to burst if you don't have something done about it, and that's a lot worse than a regular appendectomy. Would you rather have the discomfort of 3 small incisions from a laparoscopy, or have to have them slice open the whole front of your abdomen to vacuum out the vile infected juices that spew out from a burst appendix?",
"Imagine trying to clean out the interior of an inflated balloon without letting the air out, because that's what you're proposing would entail. Typically the blockage is because of its own inflammation as the bacteria inside your appendix begins to grow and multiple. The appendix begins to swell, bloated with bacteria and their toxic waste products. The shit inside there wants to get out, but letting it out could be disasterous to your immune system.\n\nIf you think you're having symptoms, man the fuck up and go see a doctor. For crying out loud, they can do these surgeries with incisions smaller than a pencil. You can literally go in one morning, get it removed, and be home in time for an ice cream dinner.",
"You. Hospital. NOW.\n\nSeriously, this shit can and will kill you. If your appendix bursts you WILL become septic, you WILL have weeks or months of recovery AT BEST, and you might just die, horribly and in agony.\n\nDo not wait, go to the hospital, go to the hospital yesterday.",
" > EDIT: I appreciate the concerns. But I cannot depend on medical advice here. I will be seeing a doctor tomorrow. Still waiting for a satisfactory explanation.\n\nI think OP might be a retard..."
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60caeh | why is it so hard to use our non-dominant hand for things like sports? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/60caeh/eli5_why_is_it_so_hard_to_use_our_nondominant/ | {
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"Since you've been able to control your fine motor skills you have been favouring your dominant hand for most things which means that the muscles in that hand are are more finely tuned and have more 'muscle memory' than your non-dominant hand. Your non-dominant hand just hasn't had as much practice doing things. "
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43r5cj | why does it take so long to exonerate criminals through dna testing if the evidence is right there? | [deleted] | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/43r5cj/eli5_why_does_it_take_so_long_to_exonerate/ | {
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"It's a real simple answer. Perhaps you've seen the Shawshank Redemption, everyone claims to be [innocent.](_URL_0_), so there's a plethora of people claiming to be innocent. \n\nJudges, prosecutors and the cops aren't in a hurry to reinvestigate old cases, and find mistakes that they or their coworkers may have made. Plus plenty of new cases, and a backlog of current cases to focus on. So that only leaves lawyers willing to work for free or very little pay. \n\nThey comb through the cases to find the cases that seem most likely to win. That takes time, and money."
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ppmc4 | why does thinking require so much energy? | A few hours of intense studying leaves me feeling exhausted. Why does this type of mental work wear me out? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/ppmc4/eli5_why_does_thinking_require_so_much_energy/ | {
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"To add to this question: what is physically happening when we think and where is the energy going? I know our brain has synapses and works with a lot of electrical signals. Does concentrating require more \"electrical sparks\" to activate more frequently? This is a great question, OP.",
"Essentially, when you think, signals travel through the nerves in your brain. When two nerves connect there is a synapse. Signals are transferred across the synapse by diffusion of neurotransmitter chemicals. After the neurotransmitters diffuse, they have to be moved back into the first half of the synapse, so that they can carry another signal. This happens via a method called active transport, and is the reason for the energy use.\n\nEDIT: To clarify, synapses are one-way connections. The signal is carried across by the diffusion of chemicals called neurotransmitters, which are released form the first half of the synapse, and detected in the second half. Once they are detected, these chemicals hang around. To move them back into the first half of the synapse requires energy.\n\nEDIT2 Concentration does require far more signals to transfer than simple reflex actions.\n",
"Your thoughts add little workload to what your brain does. Mental tiredness is more to do with patience, you can train yourself to not get tired or you may find some things challenging but enjoyable and therefore not tiring. Five year olds have little patience, and no-one expects them to have much patience. Adults would rather you are tired out most of the time, but you should ignore anyone saying you ask too many questions.\n\nFound these (the abstract is eli10) _URL_1_ and _URL_0_"
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8344rz | how do free games (like fortnite) make profit? especially for a 3d game which employs alot of artists, developers, etc. how do they pay all of these people and still earn enough money to keep the company moving forward? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/8344rz/eli5_how_do_free_games_like_fortnite_make_profit/ | {
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"Microtransactions. They offer a bunch of stuff in game that you can buy. A lot of mobile games get ad revenue as well, but it's mostly in game purchases. ",
"Microtransactions and ads. Most of the great free to play games are based off of cosmetics and loot boxes (The thing everyone is currently bitching about) and ad revenue. There's quite a few people lobbying to get rid of loot boxes. Which will effectively do away with good free to play games. (I understand for full price games why it's dumb) micro transactions can be done tastefully out horribly. It's sad when you say the word micro transactions people cringe, but they've paved the way for some great games.",
"You pay $1 here and there to have different color outfits, mounts (horses), swords, armor, etc. Same performance, just different colors or styles. People like to have a \"unique\" look in-game, and $1 doesn't seem like much, so they pay. Millions of players pay a few dollars each, resulting in huge profits for the game.\n\nThat's micro-transactions.\n\nSome games keep microtransactions restricted to \"fluff\" (outfits etc.), so that the actual game play is kept balanced and \"fair.\" Other games force you to pay to unlock the higher-level or better-performing gear, which results in higher profits but also players being unhappy with the blocks."
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5mkash | if i have a source of light like a flashlight in a dark room, how can i see things that, when the light beam bounces off them, it doesn't reach my eyes? | For example, if I'm holding a flashlight in an otherwise dark room, which I'm pointing at a wall at an angle, how can I see the wall? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5mkash/eli5_if_i_have_a_source_of_light_like_a/ | {
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"The light that reaches your eyes did bounce off into your eyes.\n\nSurfaces don't perfectly reflect light. Then they would all be mirrors!\n\nThe light bounced off in all sorts of directions. Some of that light reaches your eyes.",
"imagine that you are in a room in witch the floor is all covered in rocks. random rocks of all sizes and shapes. if you vertically drop a tennis ball it will not bounce vertically because the floor wasn't smooth. \n\non the micro scale the wall, too, isn't smooth and the photons will scatter in every direction once they hit said wall. some of these \"stray\" photos will reach your eyes and that's why you can see the table. ",
"The light hits the wall and the light scatters. Some of the light will \"bounce\" like a ball in the direction you are thinking of (and will bounce and illuminate other objects) but some of the light will just scatter *everywhere* and some of that scattering light will beam into your eyemeats.\n\nIf you can see it, it is reflecting photons into your eyeball, whether you know where the light is coming from or not."
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2cz5bv | why does spraying on aftershave stop little cuts from bleeding? | It was taught to me as I started shaving and for the most part, it works. If you nick yourself shaving, a dab of aftershave on the offending spot will stop the bleeding almost instantly. Sure, it stings, but that's better than walking around with an open wound.
I happened to cut myself this morning as I was preparing for an interview, which got me thinking about it. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2cz5bv/eli5_why_does_spraying_on_aftershave_stop_little/ | {
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"My best guess would be something like the alcohol causes the blood to clot near the surface. Alcohol dehydrates substances due to its low enthalpy of vaporization (the energy required to change something from a liquid to a gaseous state). Also though on a small scale it would have little effect, the alcohol in your aftershave would also sterilise the cut preventing any puss like fluids escaping. A combination between these would result in the cut appearing to heal faster, though I'm not determined that it would actually limit blood loss, it is more likely it just appears that way.",
"Alcohol irritates open blood vessels and causes them to constrict. It also causes your skin to contract and pinch off the bleeders."
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3mkktj | does a company forcing you to change your password every 6 months (for example) actually increase security? as far as i'm concerned it just causes me to forget my password. | Edit: since I'm taking a beating because this is a question that is able to be answered with yes or no... I'll add to it:
"then why do companies and websites force you to change them?" or "how does it make it more secure if I change it from apples1 to oranges2?"
(Even though most of you already answered accordingly before I got a chance to edit.. Some were not as kind) | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3mkktj/eli5_does_a_company_forcing_you_to_change_your/ | {
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"Studies have shown that mandatory password changes actually reduce security because people tend to either use simpler passwords that are easier to remember, or they just write them down in easy to find places. \n\nEdit: since so many people have asked. \n\n_URL_0_\n\nEdit: don't know how this turned into my highest karma post. I went from 1.3k this morning, to this!! Lol",
"In a cyber security class lab where we have to hack a computer, the password is on a post-it note under the keyboard. That also shows up as a multiple choice question on finals in other classes where I was the TA. \n\nIf its not there, use the picture, the coffee mug. But any place witha 6 month policy also has the majority of passwords on post its under the keyboard. ",
"The theory is it limits the damage that can be done by people who knew passwords at one time to the window when the passwords are valid.\n\nIn practice, not so much.\n\nJust for fun, try calling up your company's help desk and saying you forgot your password and need it reset. If they don't have some reasonably foolproof way of authenticating you, then your company has no IT security.\n\n",
"As others here have said, it decreases security. I hate to be the resident cynic here in ELI5, but here's the truth of the matter: Your organization is going to be compromised. It's not a matter of if, but when.\n\nAll of the steps your organization impose may make it harder, but it doesn't make it impossible for nefarious actors to get into your systems. What all of this security theater does do well, however, is provide layers of cover for people in your organization to hide behind when the excrement hits the air conditioning. These policies allow those in charge to say, \"We were doing everything right! We were following the policy!\" Without any consideration as to the actual value of the policy.\n\nIt's been reported that the OPM hack, perhaps the most destructive intelligence coupe scored against the US government ever, was facilitated by a legitimate password that was given away during a phishing attack. The Chinese, Russians, or whoever don't even have to snoop around in your office to look under your keyboards for written passwords or go all Neo and find an electronic vulnerability in any system. All they have to do is send a well crafted email to the right person and ask politely and they're in.\n\n",
"Where I work, a mandatory pop up every 30-days prompts you to change your password or you can't do any work or even log in to do anything. ",
"I wish I only had one password for work. I have a total of 11 passwords and 3 PINs that I have to keep track of for different apps and security logins. There's 5 different password schemes and the only way to keep track of them is to change them all to the same similar thing when one has to be changed. It's annoying. Lots of people have to use post it notes and simple text files to keep track of them.",
"Every six? Try every three.",
"Where I work there's a policy that your password must be at least 16 characters in length. Passwords change every 6 months so \"password password\" is totally legal. Is this secure? Probably not. Is it easy to remember? Absolutely.",
"I email mine to myself with the logic that if someone is in my email, they can reset passwords on any other account anyway... but you better have a damned good email password too",
"These days I think I would prefer stripping down and doing a full body biometric scan to access my stuff than have to remember a billion passwords for sites all with a billion different password rules ",
"It reduces security, but placates the auditors with one less finding. Unless they are smart enough to audit for multifactor.",
"Password changes are essential for many reasons. \n\n* People re-use their passwords across services. If we don't force password changes, it means that if someone finds out your Facebook password, they probably know your network password too. \n\n* People move on. So Jenny in IT gets fired, but she knows dozens of passwords. If you don't force regular changes, she will know these passwords even in 6 months. \n\n* IT is sometimes lazy. If an account is not removed for any reason (clerical error, IT laziness), at least you can be assured that the account is essentially not functional at the password change boundary. \n\nThere are many other reasons, but I think people can see the point. \n\nAddressing the OP's claim that he forgets his password, it's just so simple to make a super-secure password, without making it hard to remember. Your Middle Name, your Wife's maiden name, your son's middle Name, your address, and * could make this password : \n\n HarveyWilsonTrent8790*\n\n(Yes, if a person has access to a local hash and rainbow tables, this isn't perfect, but it's amazing against web and other brute-force attacks)\n\nSource : Director of IT for two small businesses",
"I actually am a software engineer for a biometrics company and I can tell you that no, they don't because people will just start to write them down places..which is way worse. This is actually one of our selling points for introducing biometrics into the workplace. Our software integrates with Active Directory and will allow users to scan their finger to login to windows instead. \n\n",
"The Information Security field no longer recommends frequent password changes as users will simply resort to writing the password down, undermining the entire point of the password in the first place. ",
"You should consider using KeePass. Its a password safe. You make one really hard password and remember that. You use that password to open your 'safe' and gain access to all your other passwords.\n\n_URL_0_",
"Let's take it to the extreme. Would your password be more secure if you changed it every day? Every hour? Every minute? If you changed your password every second, it would be extremely unlikely that anyone but you would be able to use the password (note that this doesn't mean the system is \"secure\").\n\nObviously, changing your password every second or every day is impractical, so IT security folks have come up with a tradeoff between practicality, convenience, and security and determined that 90 days, or 180 days, or whatever your company chose, is the right amount of time.\n\nThe reason that companies choose these password expiration times is because if an attacker is already in your system, this will limit the time that they have access. Also, if an attacker has acquired password hashes for your system and broken them, this mitigates the risk there also. If the password hash is strong enough that the attacker takes 60 days to crack it, it's useless by the time the crack is complete.\n\nIn reality, there are much better security measures to take such as multi-factor auth, strong password-reset procedures, and strong password policies in the first place. \n\nUsing a strong encryption and having password rules like \"minimum 16 characters\" in conjunction with multi factor and strong reset procedures is the way to go.\n\nSide note on password rules : if you're the person that creates password rules, you only need ONE! Minimum 16 characters. Don't require special bullshit like upper case/lower case/special characters - increasing the password space doesn't increase security nearly as well as password length does. Educate your users to use a passPHRASE as well. A good password can be completely made up of dictionary words, it just shouldn't be a notable quote or literary device such as \"it was the best of times, it was the worst of times\". Sure, this would be a great passphrase in theory, but a strong table might get this one pretty quickly. Something like \"my black and decker drill is eighteen volts\" is much better.",
"This is about the laziest way to \"secure\" anything. Sadly, a good deal of large corporations do this instead of investing a bit more time in proper security.",
"Forcing you to change a password is one of the stupidest things. If you wanna care more about security, just introduce a 2-way authentication.\n\nIt is much more comfortable than forcing the change and even if someone guesses your password on the other side of the world, they will not have access to the code from your cell phone.",
"Imagine some hacker gains access to the password file on the server. Assuming the passwords are hashed well, it could take weeks or months to brute force crack (if the passwords are strong). Hopefully by then most people will have changed their passwords.",
"Some people like to use same passwords at every site. There are frequent news about passwords being leaked from public sites, for example Linkedin. If users have the same passwords in the company and in one of those hacked sites, an attacker can use these passwords leaks to gain credentials in your company without ever defeating your security.\n\nIf you force users to change passwords, they cannot have the same password in use in your company's internal systems and public sites. So in theory it increases security.",
"I have to change my password every 3 months, it is incredibly difficult to remember something with a capital letter, number, and special character that is 8 characters or longer. I've started using my children's names then 123! or 1234! That is super secure, I'm sure.",
"Old job forced a password change every 6 weeks and limited you to having between 6 and 8 characters, at least one upper case letter and one of a list of 3 possible special characters. Other special characters were not allowed.\n\nSo of course everyone had a five letter word with the first character capitalised, followed by an exclamation mark and then two digits starting with 01 and going up by one every six weeks. But it was only protecting people's financial information, so no big deal, right.",
"No. The notion that changing passwords frequently increases security is a myth, which is perpetuated by lazy, incompetent corporate IT people.\n\nIn fact, forcing people to change passwords frequently *decreases* security, because people can't remember them, so they'll either write them down (where other people can find them) or use easy-to-remember (and hence guess) passwords.\n\nFurther, when theft of passwords *does* happen with malicious intent, the passwords are used almost immediately, because even without an enforced policy, people sometimes DO change their passwords periodically. If a company detects a password theft, THAT would be a good time to require password changes.\n\n",
"I once sent out a memo to get the XP computers we were still using replaced, backed up with sources detailing the security and compliance risks involved in keeping these things around for daily use. Local IT supervisor didn't take it very well, and my passwords (only mine) started expiring every 30 days. Oh well.",
"I used to work in support for a company which enforced a 90 day password expiry, and remember the previous 12 passwords. We had a need to sometimes log on as the user to sync their files to a new device, if their current one they have (in the field, like remote sales staff) was damaged/inoperable. \n\nI never had anyone question me when I said \"and I'll need your password\" they just gave it over freely. It's against company policy, and no one gives a shit. To say social engineering is the easiest way to obtain a password is an understatement. \n\nAfter 30 or so times of this happening, it was pretty apparent that 90 day password policies suck shit. 'Giraffe123' 'Monday1' 'Winter1' 'Summer1' etc. and increment to the next number. Typically it was always capital first letter, generic word, number (like my examples above).\n\nSo to summarise, 90 day policies suck shit. It would be better to have an annually changed cryptic password policy (e.g. subject the password to a strong means test / length requirement). If a breach is detected then it should be changed but until then there's little point. Setup 2-factor authentication or something to mitigate risk of compromised passwords.",
"The more often a company forces password changes, the more often you find post-it notes with passwords under people's keyboards.\n\nI used to work for government. Password Post-its were everywhere.",
"From a security perspective, you're much better off using a simple pass phrase than a password, and then not changing it.\n\nFor this to work, the IT department needs to be on point for disabling accounts of people who separate though.\n\nFor example if you use a password like:\n\"My daughter Tina's birthday is December 7th.\" \n\nWith spaces and punctuation, your password is super easy to remember, but really difficult for any sort of password cracker.\n\nAlso, most password crackers don't do brute force anymore. \n\nWhen I'm doing a security audit, I just dump the password database, and paste the hashes into a rainbow table. Cracking most passwords takes seconds, not hours, months, or years.\n\n_URL_0_",
"If you need a password for a fellow workers computer:\n\n1. Look at the post-its around edges of the monitor.\n2. Look under the keyboard and at the bottom side of the keyboard\n3. Look in the top drawers.\n\n90% chance of finding it. This is from personal experience as a consultant working at a bank. Your money is safe with us...",
"Per corporate policy we have to change every 90 days (major tech company). My entire team just changes the number +1 each time, making it less secure.I'm trying to use lastpass for my online accounts at least",
"I work for one of the largest banks, and we have to change our password every 3 months. We're also not allowed to use the same password we used the last 5 times. I forget my password quite a lot since we have to use a combination of caps, symbols, and exactly 8 characters total. Every time I call IT they make sure to completely verify you. They ask questions that sometimes I don't recall the answer to. The problem to me is that since we change our passwords quite a lot, and on different platforms, we end up writing them down and keeping them on our working area.\n\nI'm not worried about IT department, I'm more worried about my coworkers or the people that go through our area.\n\n\nAlso, at my college, they reset our password every semester to our birthday. It's so easy for others to gain access just by knowing my birthday and my login ID (which is my last name,underscore, and a number for everyone)",
"It used to make sense, a long time ago.\n\nA long, long time ago, Unix systems kept password hashes in a world-readable file. (See _URL_0_ for details.) So everyone had access to everyone else's hashed passwords. And the password encryption scheme at the time only supported passwords up to eight characters. Given enough time and computing power, it was almost certain that an attacker could eventually crack a password.\n\nPassword expiration policies mitigated that risk. Suppose it takes an average of 6 months to crack a password. (Someone actually did the math back in the 1970's.) If you force users to change their password every 3 months, then it makes it very unlikely that an attacker will have enough time to crack a password before it expires.\n\nNowadays, it's much more difficult to get hold of hashed passwords. And like others in this thread have said, forcing password changes makes it more likely that people will forget their passwords or use simple patterns. So periodic password changes make much less sense now.",
"Can someone explain the mechanics of how new passwords get rejected for being too similar to previous ones? In theory, a hash of \"password1\" should be completely different than \"password2\". So does this filter method keep some less securely hashed data in order to block similar passwords?\n",
"It's like a lot of things; it's a great idea if you only had ONE password to worry about. I work in advanced telecom with maybe a dozen applications, all with differing password protocols. Most people just write them on the back of their notepad, phone call register or what have you. So much for security. I DID discover a clever way to incorporate upper and lower case, a number and a weird character; Use names, like your parents or any comedic pair, like Martin and Lewis, Abbott and Costello, and format it like this : Abbott & Costello2. Like \"Abbott and Costello too\". Use your parents name, kids names or whatever, it's a hell of a lot easier to remember.",
"My companies security is obnoxiously good. I have 3 passwords to get into anything worth seeing on my computer. One lets the laptop boot, one for Windows, and the third for email/files. New password every 90 days, 10 characters minimum, must include a symbol, lower case letter, uppercase letter and number. No more than 5 letters in a row can be repeated from any previous password ever. If you need to reset it, they physically call you and verify identity. Good news for our clients though I suppose. ",
"Full Disclosure: I work for LastPass.\n\nIf you use a unique password for work only, it typically does very little to increase security, if you use that password ANYWHERE else it does a lot to increase security. Unfortunately most people reuse passwords so the policy tends to makes sense. \n\nIn my opinion you're far better off implementing secondary factor for login (e.g. _URL_0_) and then have a yearly password change policy.\n\nMy favorite story about how badly enforcing password changes too often can backfire involves a woman who was forced to change her password every month, had to have caps, numbers and punctuation, and it kept track of her last 50 passwords. She was proud of her method of dealing with this problem, her password was MonthnameYearNumber!\n\nJanuary2015!\nFebruary2015!\nMarch2015!\n\nShe always knew her password and was able to do it forever, she had no clue how insecure it was -- she had a problem and solved it. You can't trust people, use a secondary factor.",
"it's all fun and games till some one gets your password and a Sony corp incident happens again! if you have a hard time with passwords just use 1password or lastpass to store your passwords that way all you remember is two passwords. your windows log in and you 1password or lastpass password. ",
"No, it decreases security. It motivates people to use passwords like \"Goldfish2014\", \"Goldfish2014b\", \"Goldfish2015\" etc.\n\nLast time I worked at a place like that, I came up with a password so awesome it took me 2-3 weeks to get it into my typing-muscle memory (this was before exposure to Correct Horse Battery Staple) and soon afterwards I got a prompt saying \"o hai, we require password changes _every fucking month_, also we fucking save your last N passwords in an unencrypted format so you can't recycle them\".\n\nMuch of the time, the IT people know this is bad. The problem is that this kind of a policy lets the big decision makers claim to investors or regulators that they follow very aggressive \"industry best practice\" security measures. It's the XML of the 21st century.",
"System Administrator here for a local school. This is called job security for me. 90% of my job is resetting passwords.",
"Imagine a number line that looks like this:\n\n < - **usability** -------------- **security** - > \n\nWhile recent studies showed a reduction of security on more frequent forced changes, forced changes does do something important. Offline cracking can brute force the majority of individual passwords in very little time... usually less than a day, but for the more complex ones a human might use, 1-2 months or longer. These breaches of security might not get caught immediately, either.\n\nDue to offline cracking, it is much more important for privileged users (root or admin) to change passwords frequently, and to use complex passwords. Writing it in your wallet should be good enough. hell, just remember the first and last characters and write the rest in your wallet if you're really concerned ... if someone finds your wallet at least some security-through-obscurity would help significantly. It's possible, for instance, for someone to snag a privileged password file but not be able to assume admin privs remotely. Offline cracking would allow this.\n\nLastly, good security depends on estimating the cost of a breach. If you're protecting a database of vitamin water reviews of a personal blog, you probably don't have to be as diligent as if you're protecting a database of weapon designs from a national lab. If your company has critical data online, what's the worst thing that can happen? Whatever that answer is will determine how secure things need to be made.",
"So in a sort of theoretical sense, a lot of the password requirements that your company has will improve security. For example, rotating passwords on a regular basis cuts the amount of time someone has to take advantage if your account gets compromised. If you haven't changed your password in 10 years, then anyone who has ever known your password in those 10 years, whether you shared it with them, they looked over your shoulder, or they somehow \"hacked\" your password, they can still do damage. Change your password right now, and your account become secure again.\n\nSimilarly, having long random passwords with numbers and symbols are harder to crack with brute-force methods. Keeping a password history and preventing you from using one of your prior passwords keep you from switching back to that password you used for 10 years. All these measures are improving security... theoretically... sort of...\n\nThe problem is, it also makes you more likely to forget your password, which means you'll probably write it down or store it somewhere. Then your account is only as secure as the sheet of paper your password is written on. Or worse, people get frustrated by the requirements and come up with a way of making it simpler. For example:\n\nI once worked at a place that required your password be at least 12 characters, with at least one uppercase letter, one lowercase, one number, and one symbol. The password had to be changed once a month, but it started warning you two weeks before expiring, so it would nag you to change your password every two weeks. It kept track of your last 10 passwords and wouldn't let you reuse them.\n\nThis is over-kill, and is likely to cause more security problems than it fixes. Most people wrote their password down on post-it-notes and stuck them to their monitors, which meant anyone sitting down at their computer knew their password.\n\nA bunch of people, however, figured out an easy way to come up with memorable passwords. They started cycling through a list: Password0!, Password1!, Password2!... Password9!\n\nI brought this up to the IT manager, and he didn't care because he thought those were \"strong passwords\" because they met the requirements. I tried explaining that those are terrible passwords, but he didn't seem to understand.",
"\nIt varies case by case but I suggest regular password changing ISN'T WORTH IT unless it's very easy. It interferes with your a\nbility to remember them.\n\n * Fred Cohen revisits his 1997 writing _URL_2_\n * RJA - _URL_3_\n * Spaf - _URL_0_\n * Schneier - _URL_1_\n\nAnybody arguing that something tiresome is a \"best practice\" should be asked to prove it.\n",
"It depends on what kind of security you're preventing. It absolutely works in some ways and dramatically hurts in others. It will limit an outsider's capability of getting in by 6 months if they saw it on someone's piece of paper or heard it out loud -- but it's still only a part of the puzzle they need to get in.\n\nAt where I worked security was a *huge* deal but people still took it very lightly. Because of the clearance and access we had for some people -- it meant some fairly large law violations for breaking them. Even *then* -- people still didn't take *too* seriously.\n\nPersonally, I told them which passwords *really* mattered and which ones didn't. I also warned them of the consequences of someone \"stealing\" their password on each system (some systems carried different legal requirements and other obligations -- you had to basically pass a \"don't be a dumbass\" test to even legally touch that computer, you *then* had to pass *another* test to get a login for it).\n\nThe thing is this protects against a very specific kind of attack. It does fuck all against social engineering and even makes social engineering easier for *certain* systems.",
"I was on a stretcher in the hospital. All I remember hearing was hospital workers talking about how you should change your password to affirmations. QuitSmoKing@73",
"We are forced to cycle all of our passwords every 6 weeks. We use LastPass to hold them all so we just technically have to remember that one to get into LP and use 2-factor auth. So it's kind of like one PW to rule them all. ",
"My school constantly made us change passwords. I'd always put it off because it was annoying as hell. Then a day would come when I really need to send an important email and I get locked out of my account because I hadn't changed my password yet. Beyond infuriating. ",
"If nobody knows the password it is the most secure thing :)))\nI generate random passwords and use keyring to remember them. So I have to remember just two passwords",
"99% of non-techie people's password list:\n\nwhateverpasswordyouwant\nwhateverpasswordyouwant1\nwhateverpasswordyouwant2\nwhateverpasswordyouwant3\n(...)\nwhateverpasswordyouwant136\n\nSo no, while it's probably wise to change your passwords after some time, forcing people to do it is just annoying and doesn't really improves security.\n\nAnd dumb password complexity rules are harmful too. No one is going to find a 50 characters long password, even if it's only lowercase letters.",
"I used to work at Bank of America. Had to change my password every 20 days so I just used a formula. Lets see if you can guess what's next.\n\n1Bulbasa\n2Ivysaur\n3Venusar\n4Squirtl\n\nAlso for some dumbass reason your password had to be 8 characters exactly.\n",
"My work forces us to change PW every 30 days... and I have around 20 different programs/tools/servers I use that each have different PW requirements and limits... so yeah... obviously they are going to be written down somewhere...",
"Perhaps you should just use a password manager and generate random strong password. No need to remember anything and no need to use crappy passwords.\n\nLastPass and KeePass are free so there's no real excuse in not doing so.",
"Companies forcing you to change your passwords every certain period of time probably means their cyber security is cheap and they want to limit damages from people getting pass logs(trying to get people to outdate their logs) instead of dealing with their clear breach holes.",
"Find an obscure Fantasy/Sci-Fi book from before 1990. Find a long phrase. Use that as your password.",
"In my opinion, no it doesn't. My school requests passwords to be changed every quarter. Me being an IT security major actually used a very secure password and got very annoyed every time I was forced to change it. I requested multiple times to use 2FA instead and force it on everyone. Currently I actually use different complex password for every site and use lastpass to manage them. I secure lastpass with a master password in conjunction with 2FA yubikey. Haven't had an issue ever with this setup.",
"No it doesn't increase security in the slightest. If anything it is one of the root causes of why security is so bad in the office environment. Basically Complex password + Frequent changes = Passwords written down or other notoriously bad habits.\n\nThe background - I've been in the Corporate IT environment since 1998. I've seen A LOT of change and an equal amount of terrible habits. I've worked everything from helpdesk up to Cisco engineer.\n\nThe reality of the matter is, It professionals are the ones to blame for passwords being the giant mess they are. Yes that is right, I said it. We the ones who made the rules and taught users how to abide by our rules did it wrong. In short we have taught users how to create passwords that are impossible for the average human to memorize, yet frighteningly easy for computers to crack. As such the first step that needs to happen is that We IT professionals need to STOP implementing stupid password policies. About 5 years ago I came to a realization. That realization was that it is entirely possible to create long passwords that are easy to remember, yet impossible to crack. Now in this case, password might be the incorrect terminology and given that the \"password\" has gotten such a negative stigma over the years, it is time to adopt the term \"Passphrase\". \n\nOk so let me break this down further. I will use _URL_0_ as my example site as I generally feel their results are a little more realistic. \n\nPassword Example: S32G@#13d\n\nThis is a 9 character password that adheres to the rules and policies of probably 99% of the websites and internal networks out there. it is entirely random, it is nearly impossible for average joe to memorize and yet..it is Pathetically unsecure. A Modern PC can crack it in 275 days. But you think, \"That's almost a year! how can that be unsecure?\" Because a single PC is almost never going to be used to crack it, Thousands are. And when you put thousands of PC's (a botnet) to the task of cracking a password like that? Well it has a lifespan of a few brief minutes before it is rendered useless.\n\nSo let's talk about a Passphrase and show the difference. Now first because there are many words involved in a phrase, there is an endless variety of ways you can change it between websites and still keep it easily memorized. So while I am going to give one example, it is just an example and you can be as creative as you want. The biggest strength to the passphrase is it doesn't matter how long it is, anyone including grandma can memorize it because it is a phrase that has meaning to that person.\n\nExample Passphrase: Thisismyexamplepassphraseforreddit!Itissupereasytoremember!\n\nThis would take a PC 4 novemvigintillion years to crack. I don't even have a personal concept of how many years that is, but suffice to say the easy word is NEVER. This includes a botnet no matter how many computers are involved. Nothing and I mean absolutely nothing on this planet is cracking it. On top of all of that it is almost criminally easy to memorize. Now you will note I included the word reddit in there. I did that on purpose as that is what I call a \"designation word\" within the phrase. What that means is that you can keep the same overall phrase through any site you visit and only change that designation word and have an easy to remember constantly changing phrase with 100's of variations. It doesn't require the use of a password manager which is a single point of failure, it doesn't require bio metrics which at a consumer level are laughably easy to get past. It simply requires the IT Admin to implement a Single Policy.\n\nPolicy: Passwords must have a Minimum of 30 characters. \n\nThat's it. That single policy combined with a concerted effort to reeducate end users AND ADMINS and abolish the absolutely absurd password rules we currently have. Will render forgotten passwords a thing of the past, increase website and network security by an order of magnitudes and bring an end to the absurdity of \"change your password every 90 days\" policies. ",
"Hell, nothings safer than having your account be so safe that you don't even know the fucking password. ",
"We call practices like this \"security theater.\" It makes the authoritative entity (business, government, etc) look proactive and effective.\n\nIn reality, security theater just tricks the simple minded into believing that they are safer, while also providing plausible deniability for anyone in charge when a real attacker comes along and actually does damage. ",
"I like reddit's security measures. You can type your password in a comment and it will automatically censor it like so: ********",
"The current standard is this:\n\nPasswords must be at least 8 characters, alpha-numeric with uppercase, lowercase and a number or symbol; changed at least every 90 days; maximum of five wrong entries before being locked out.\n\nThe reality is that a password that meets current standards does almost **nothing** to protect a user. A study in New York found that those who had their accounts accessed via their password was because the person using it saw it used or found it on a piece of paper and used it immediately.\n\nWhat does make a **secure** log in is not a password but a pass phrase. For example, if you love pizza, your phrase could be something like \"pepperonipizzawithextracheeseandolives2go\"\n\nPicking a phrase that is easy for you to remember means never writing it down. Using a phrase with a very long string makes it extremely unlikely to hack. According to _URL_0_ the phrase above would take a desktop PC about 50 quattuordecillion years to crack.\n\nCompare that to an 8 phrase alpha numeric, which is about 15 hours!\n\nSo the best answer is, create a phrase you will remember but it is unlikely someone else would think of (eg. \"Ihadabluetricyclein6thgrade\") Then, when you have to update your pass phrase, add a number somewhere like \"1Ihadabluetricycle in6thgrade\". Update the number each time, 1-0, then put the number at the other end. Easy to remember and if you forget which number you are on, you are only 1 or so away from getting it right.\n\nSource: Information privacy consultant with a major tech firm, consultant to government. The above constitutes my recommendations to users. ",
"Not trying to be mean, but *HOW* is forgetting passwords such a prevalent problem??? I have three decently complex passwords that I've memorized and I use them for different things. If I had to repeatedly change passwords I'd simply cycle between them. ",
"I think it actually makes everything worse.. people will use passwords like \"disismypass1\" and change it to \"disismypass2\" and so on.. The time a password is used is not the problem, the password itself is and having to change it ever X times a year does not help with that. Maybe services should try to log into some websites with your password (of course not storing any data) and showing the user how easy it is to get your information by using the same password...",
"People have pretty well covered that password rotation can decrease security due to the human element and laziness. Password rotations are beneficial under certain circumstances, which I'm sure someone else has covered in this thread. I'll move on.\n\nIf you give people tools to remember their passwords for them, complexity seems to get a little better. Password managers like LastPass and KeePass/KeePassx do wonders. My passwords are no longer under 20 characters if I can help it. Instead, they're random long strings. This can work for usernames as well. Here's an old banking username that I no longer use:\n\nT+ewpiO.jhajU0asFe@bBa!fajOvqcph_idIpKis[lupBeelredA\n\nI can't remember that, but my password manager does.\n\nDeploying standardized password management utilities for my department has seen good participation. There are a very few cases where people simply refuse to use them. I hate to say it, but they're also the oldest people in the group. Almost everyone else is opting for two factor auth as well.\n\nPassword managers are nice, but they're usually by default only protected with a single password or passphrase. Pick a weak password there, and you've just handed over your entire password vault. This is where two factor auth comes in. [Yubico](_URL_0_) makes a USB key which is recognized by your computer as a keyboard. By pressing and holding the circular area, the Yubikey produces a one time password. Another option is Google Authenticator, which integrates with quite a few password managers. Gaining access to your password vault without the second factor makes the password vault an unattractive option (more work than the contents are worth).",
"Back in the early 2000's when i was an asshole kid, i was on this site where you could chat together and collect stuff and money.\nI used to hack other people, by giving away a dummy account, with a non transferable \"home\". When the recipient changed the password of the account, i could use the \"i forgot my password\" function, and the system would just straight up send me the password that i forgot. 20% of the time, the password was the same as the one they used on their main account, so i could quickly steal all their stuff, change the password of my dummy account, and repeat the process on some other unlucky guy. ",
"Does it bother anyone else that the site remembers your password so they can tell you you're not allowed to reuse it?",
"Have you heard of our lord and savior, keepass? ",
"The idea behind it is to do damage control on leaked passwords. Always assume that someone will give out their password. If they change their password every 90 days it reduces the attack window to less than 90 days.",
"Where I work, passwords are important. The strict password policies (changing every 90 days, using 16 characters with special characters) have resulted in everyone relying on the same tactic of making vertical lines down the keyboard and saving the password to a text file on the desktop. Epic fail, IT, epic fail. I'm inclined to believe that if I were allowed to use a four letter password, it would be too simple for anyone to crack.",
"I'm not in IT, but theoretically wouldn't that stop brute force attacks? If your password is long it would already take a long time to brute force it, and constantly changing password would make it near impossible. \nTL;DR Long + Changing Password = Bad Brute Force Attack",
"Given enough time, any password can be discovered, just by guessing random passwords (aka brute forced). When you change your password, you're essentially forcing the brute-forcer to start over, and forcing a reset means they have a 6 month window to try every possible password combination, and if you have a strong password, that may not be possible\n\nThat said, I get the feeling anyone who does that any more has a really lazy tech/security department who don't do their jobs & leave plenty of security holes that don't require a password anyway.",
"No, because after the second time I have to start writing them down on a sticky note because I forget what the latest password was, sometimes I'll accidentally enter the password from 3 months ago and get locked out. My job also has insane password requirements. One uppercase letter, a lowercase letter, a special character and must be at least 8 characters, but no longer than 12. You also can't use a password you previously used.",
"This is hours too late, so I'm just giving you an anecdote of my time working on a call desk for a large corporation. \n\nWhen I started working there, there was a 6 month policy in place, and then - for whatever reason - it was changed to a monthly policy. The problem, of course, was that the password restrictions were extremely loose - as in 8 to 16 characters, at least one number, and one capital letter. We just set piss-poor passwords each month so we didn't have to deal with calling IT for password resets. For the few months this policy was in action, every member of my team was using either \"MonthYear\" or \"SeasonPassword#.\" As soon as the IT team realized why they weren't being inundated with password reset requests each month, the policy got changed. Still, I consider it one of the funniest, most illogical policies the management there ever came up with.",
"September2015\n\nsomeone in your company is using this password right now\n\nProbably a lot more than one person",
"You know the people with Active Directory access or any access to rest passwords can cause the most damage.",
"There is some recent research into the quantitative advantage of this policy. I learned a little about this when Paul Van Oorschot gave a talk at my University. You can read some of his papers on the subject, [like this one](_URL_0_), that basically states that the advantage, at best, is very minimal. The only advantage seems to be if someone already has your account password then changing it will stop the continued access. For almost any other attack it provides little to no advantage.",
"Most password policies are based on ancient IT folklore. The 30 day password was born in the 80's when someone set a then modern computer to crack a password through brute force. It has no relevance these days. Now the biggest threat isn't from the outside. Firewalls have gotten good at stopping that kind of shit. These days the biggest threat is a barely computer literate employee who clicks on every damn attachment that comes in through an email. Bob sent me Virus.exe? I better run that now!",
"I worked in banking and we had to change it monthly. It got to the point we just taped the PW to our monitor. Security changed it too 6 months so we taped it too our top drawer. Then they just gave strict requirements with no more changing. That worked. \n",
"It's annoying yes. Most secure systems now use a smartcard or software certificate in lieu of a password which makes life slightly better. \n\nThe people that create and enforce the password policy are assuming that the database that stores your password had been stolen by an attacker. Due to a variety of reasons, it's not possible to be sure that it hasn't, so it's safer to assume it has been. Most modern systems use what is known as a hashing algorithm to scramble your password in a non reversible way. The way to defeat this hashing is to either start guessing passwords (brute force), or to take common passwords and hash them the same way. It's then easy to see what the persons password was if the hashes are the same. To combat that, an additional bit of information is added to the hash of your password called \"salt\". That way the attacker would have to create a separate database of hashes with every possible salt.(much more computationally difficult). Password policy was traditionally based on an estimate of how long it would take to obtain the plain text password of a reasonable percentage of the passwords in a database. Therefore if you change it before the attacker had time to \"crack\" it, he still doesn't gain access. \n\nTo combat salts, attackers can also use a \"rainbow table\", which is a pre hashed and salted database of every possible password. Then the computer just has to run through the rainbow table and find a match. That way they can use your account to get what they want before you change it again. Due to this, it is now possible to obtain the plaintext version of a high percentage of the passwords in a database in a very short time. So now most password policy is based off of limiting the amount of time an attacker has to do damage. (In reality, most companies that don't employ cryptographers just enforce what is thought to be the industry best practices)\n\nFrom the users perspective, there is no way to know what password hashing scheme the owners of the system you are using has chosen, so use something like keepassx and use a different password for every system. Imagine you sign up for a website and the owner doesn't know what they are doing. An attacker steals all the passwords, cracks them, and then goes around to thousands of other websites using the same username and password pair that he obtained. Next thing you know, you can't login to Gmail anymore because you reused the same password everywhere. There is federation to combat this, but this post is already too long. ",
"Password change policies that enforce password rotation are not actually trying to prevent brute forcing (you actually don't reduce your attackers time to brute force unless they already happened to guess your new password). These policies are in place to increase password entropy. A policy like this assumes that for your first password (probably first few) that you are not going to pick a password that is sufficiently unique as to be easily guessed, or to be the same as a password you use elsewhere, which means it is open to all the vulnerabilities of that unknown system. So, if they make you change it enough, you are more likely to wind up with a password that has better entropy and is more difficult to compromise.",
"As I work on the security for my website's log in feature, this thread reaffirms a few basic beliefs I have, which is great, because I didn't feel like coding for constantly rotating passwords.\n\nAnyhow, back to reading how awful md5 encryption is.",
"The intent of that policy is to limit the duration of a successful, undetected attack.\n\nFor instance, Mozilla recently disclosed that an attacker had access to private Bugzilla information, and may have had access since as early as September 2013.\n_URL_0_\n\nI hate picking on Mozilla, because I really like the company, but this is exactly what is expected when passwords aren't changed periodically.",
"Password security is one of the most important aspects of security. Both of your examples \"apples1\" and \"oranges2\" should not even be considered as passwords unless you're willing to be responsible for someone losing information. In order to crack a password of that magnitude would take under a minute with a brute-force attack (trying password after password with different combinations of letters, numbers, and symbols) if there is no limit of incorrect attempts. You should have a very strong password using a mix of capital and lowercase letters, numbers, and symbols in no guessable order. By that I mean, don't think of a word, capitalize letters in the middle of a word, and add a number and a symbol at the end. Mix them up. These types of passwords take exponentially longer to crack using brute-force attacks. Some could take weeks if not months. By forcing you to change passwords does two things. If someone is trying to brute-force attack you, it will force them to restart the process. The second thing it does is ensure that if someone DOES have your password, they lose it. Moral of the story, use strong passwords and change them often. More often than every 6 months even.",
"Changing your password every few months protects you in case the website in question is ever compromised.\n\nLets say someone wanted to steal your password for a specific website and use it to do something nefarious. What are the ways they could do this?\n\n1. They could simply try to login a bunch of times until they find a password that works. But most sites are able to protect against this by locking out users after X failed login attempts.\n\n2. They could find a way to gain access to the website's database of encrypted passwords. Unfortunately, these types of security breeches aren't all that uncommon. If the password isn't very long or complex, they can use a large table of pre-computed password- > encryption pairs (called rainbow tables) to lookup your password. But most sites add a long random string called a salt to your password before encryption that make these rainbow tables useless.\n\n3. And lastly, they can simply brute force the encryption, by trying billions and trillions of passwords until they find one that matches the encrypted one from the database. For a modern cryptographic hash algorithm, this could take anywhere from a few months to a few years. The only way to protect against this type of attack is to force a password change (or a salt change, but that would require the user to provide their password again) every few months.\n\nThe last and probably most common way is social engineering, where someone tricks you into simply giving them your password. There's only so much you can do to protect against that.",
"Back when I started high school the computer system made us change our passwords every term, and we were grumbling about it as well. One of my friends told me that her dad, that worked at an electrical plant, used to cycle between his 4 kids names with the same numbers (his anniversary), so it might be John0305 and the next time he'd change it to Jessica0305 and so on every time he was prompted to change. I always thought it was the best way to do it, of course, he was so proud of himself for coming up with it that he told anyone that would listen.",
"Just throwing this out there, but a good way to keep your computer safe is to use a password generator. And then store the passwords in a password safe under a very secure password that you will remember.",
"When I was in Highschool the teachers stored old exams on their G drive that was locked to students.\n\nI told the Librarian I had forgotten my password but needed to get a file off the H drive (student drive) for an assignment. So she logged me into a PC, I then simply logged onto G drive, copied old exams off and profited for the rest of my time there.\n\nHumans are the issue. It doesn't matter how complex your password is if you are going to let people log in as you.",
"My work makes us do it every 90 days. Sucks. Especially considering the crazy number of accounts we each have.\n\nOne thing that has helped: RSA tokens. Now I just have to remember my pin and have my token around my neck. (but sadly not everything that we have uses RSA so I still have other passwords to remember)",
"the best system will just increase the duration between logins. once someone can only log in once a day brute force is basically out of the window.\n ",
"I doubt is increases security, but what it does do is disabled unused accounts, that HR doesn't bother to tell us about. It can also help in cases where an admin password is shared, but changes. I do this for local admin, change it regularly so that I can share it when needed to do support.",
"As an IT Auditor:\n\nIt's a PCAOB/AICPA requirement. Simple as that. Those old-school governing bodies think it increases security, so companies are forced to implement it or risk getting a red mark on their financial filings (long story there). Most stakeholders (stock owners, etc.) will see that there was an issue reported but won't bother looking into it, and that may result in them choosing not to invest in the company. ",
"My company does this. I hate it. Every three months. And the password can't be the same as any of your last five passwords. Log in? Name and password. Internet? Name and password again. Employee site? Name and password yet again. What would you like to do? Copy of your paystub? Name and password and company code. Great time to do some e-learning. Name and password. Done. Send an email? Name and password. Done. Surf YouTube? Name and password. Work on my own schedule? Name and password. I hate it. I and what we do isn't even top secret. I work for an ambulance service and no patient info is in our computer anyway. Nothing. It's stupid. It never works and we can't get help because we work 24/7 but our IT is mon-Fri 8-5.",
"Do you work for best buy? Because we have to do the same dumb shit unfortunately. ",
"When you are forced to change passwords the only real security and mitigation is that someone that already knows your password will no longer know it or someone that has a copy of your passwords hash.\n\nSomeone trying to brute force their way into your account (if that's even possible since many companies have lockout policies) won't be deterred, you may just change the password to the very next one they try, if you change it to one they have already tried them great, you mitigated it, but it's a game of chance. (brute force attacks are rare and should be caught fairly quickly)\n\nSomeone that has your password hash would lose a valid hash since your password (and this the derived hash) would be different \n\nBut the best result is the first, anyone that knows your password no longer does",
"Omg... My work requires I change it every 3 months. My password went from *********** to **********1 to ***********2 and currently I'm at ***********17",
"No it makes it more dangerous. Theirs a reason at one point 1234,ABCD, WXYZ were extremely popular passwords in corporate settings..",
"_URL_0_\nThis comic is a pretty good example of a hypothetical situation regarding this.",
"Not really, same way how disabling cut/paste on login page doesn't improve security but in fact decreases it.",
"I'm working in a high security enviroment, and we practice the three month password circulation.\n\n\nWhy? Well, simply to not have any old accounts lying around with exposed passwords still active. The passwords are not used as the primary way of logging on to our systems. Security cards and visual confirmation does a much better job at that.\n\n\nI mean, remember: No new password eventually locks old accounts.",
"Yes, it does. If someone compromised that account and had no way of getting the updated credentials, you would leave them out.\n\nSecurity is a complex issue. Most like, whatever damage they could have done would have been done before the change is mandated.\n\nBut like everything, for some cases is useful. ",
"my company name is Microsoft (it's not but lets say it is) and I'm an IT technician and everybody changes their password every six month by increasing one number. if their password is microsoft10 next six month they make it microsoft11. It's not preventing anything.",
"Yes it does since if you use brute force it would take sometimes to do it, especially with large database.\n\njust in case if some one broke it and steal your password, the perpetrator can not used it anymore if you change your password.\nI think that 6 month is not enough, each month will more secure.\n\nfor your problems to remember the password, you can always use application for it for example last pass or you can use passphare for example hotpotnoodleinsaturday you can remember it since every saturday you get your favorite meal. or if that your library account you can use anatomyatlasshelf22 since there is anatomy atlas in shelf number 22 make it random as possible but still easy to remember since in most people its easier to remember something as phrase than a word.",
"Just 6 months? My Domain admin passwords have to be reset every 19 days on my IT systems.",
"It actually reduces security because it can't enforce anything but arbitrary password rules (length, special character inclusion, and previous password exclusion), and people will gravitate towards what they can remember -- meaning easy to remember/commonly used passwords that they will then store, quite often, very near their work areas.",
"My top two password tricks: \n#1: I have the same base password phrase for every website, but alter 2 characters in the middle, which match 2 characters in the website address ( any combo works, 2nd and 5th, 4th and 3rd, etc). Thus every site i go to has a unique password which i can remember.\n\n#2: we've all seen \"new password must not match the last 6 passwords used. In one sitting change the password 6 times, and on the 7th change it back to the original."
]
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[
"https://www.google.com/url?sa=t&amp;source=web&amp;cd=7&amp;ved=0CCQQFjAGahUKEwjJv9Cgq5fIAhWJFx4KHUZFAlA&amp;url=http%3A%2F%2Fwww.cl.cam.ac.uk%2F~rja14%2Fshb10%2Fangela2.pdf&amp;usg=AFQjCNF2qjKUOmB600bflIQ3SRHk0p3_Ow"
],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
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"http://keepass.info/"
],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[
"https://en.wikipedia.org/wiki/Rainbow_table"
],
[],
[],
[],
[
"http://man7.org/linux/man-pages/man5/passwd.5.html"
],
[],
[],
[],
[
"https://helpdesk.lastpass.com/multifactor-authentication-options/"
],
[],
[],
[],
[],
[],
[
"http://www.cerias.purdue.edu/site/blog/post/password-change-myths/",
"http://www.schneier.com/blog/archives/2010/11/changing_passwo.html",
"http://all.net/Analyst/2011-04.pdf",
"http://www.cl.cam.ac.uk/~rja14/Papers/SEv2-c02.pdf"
],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[
"https://howsecureismypassword.net/"
],
[],
[],
[],
[
"https://howsecureismypassword.net/"
],
[],
[],
[
"https://www.yubico.com/products/yubikey-hardware/yubikey-2/"
],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[
"http://people.scs.carleton.ca/~paulv/papers/expiration-authorcopy.pdf"
],
[],
[],
[],
[],
[],
[
"https://threatpost.com/attacker-compromised-mozilla-bug-system-stole-private-vulnerability-data/114552/"
],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[
"https://xkcd.com/792/"
],
[],
[],
[],
[],
[],
[],
[],
[]
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2608ab | could a canadian billionaire just give 1 million to every person in canada, cure poverty, and still be filthy stinkin' rich or would it shatter the economy? | I'm curious, in theory, because it could in fact be done what effect would this have on a country? ..The world? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2608ab/eli5could_a_canadian_billionaire_just_give_1/ | {
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"wouldn't he lose all his money after 1000 people?",
"1 billion = 1000 million\n\n\ngiving money doesn't create wealth or expand economy.\nsomehow OWS/Keynesian type ppl can't grasp this concept.",
"Since the population of Canada is just over 35 million people, you would need at least 35 trillion dollars to do this. This is more money than anyone has. It's more than double the GNP of the entire United States in 2011. So, yes this would probably wreak havoc on the world economy. ",
"Good lord. I swear I went to school, and I am embarrassed to say I'm not intoxicated. Apparently my brain wasn't working with whatever crazy math was going through my head. Still was curious on the effect of in theory someone WERE able too."
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186ry7 | if police do the most vehicle chasing, why don't they have the fastest cars? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/186ry7/eli5_if_police_do_the_most_vehicle_chasing_why/ | {
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"Budget?\nThe ones that patrol the highway do have fast cars, but in an urban environment driver skills are more important than speed",
"It's not the speed of the vehicle but the skill of the driver that ends car chases. That and trees! Police want to apprehend the suspect but they must keep everyone's safety in mind first and foremost. Good question.\n",
"Because the radio is faster than any car",
"Having the fastest car gets outweighed by other concerns. Police officers may end up sitting in their car for more than eight hours at a time, while wearing protective gear, a gunbelt, and all the equipment that goes on their gunbelt. They also need to be able to transport prisoners, possibly a partner, radio equipment, potentially computer equipment, first aid kits, possibly shotguns or rifles, drug testing equipment, and whatever else they may need for their shift. They also need a car that's going to be able to do things like force other cars off the road. A car that can do all that is going to be a pretty big and heavy car.\n\nAt the same time, it's not necessarily that important that a police car be able to keep up with the fastest cars on the road, but the police edition Crown Vics had their speed cutout set for 140 mph, which is enough to keep up with most cars. You can always radio ahead for the faster ones.",
"Police in fact almost never do vehicle chasing. Car chases in cities and suburbs are basically *guaranteed* to hurt someone, so they are avoided as much as possible.",
"You might be able to outrun the car, but you can't outrun Motorola.",
"Car chases are way less than 1% of what we do. The Crown Victoria Police Package only has 240 horsepower. For comparison a new toyota minivan has 266 horsepower. Our cars are way more than just a pursuit vehicle, I hate when they are called \"pursuit rated\" because that seems to imply thats what its made for. Pursuits are so extremely dangerous, its probably a good thing we only have that 240 HP. I want to catch every bad guy out there, but most of the bad guys realize that the more dangerous their driving conduct, the faster we will end up calling off the chase. My last pursuit was against a stolen Audi S4, that thing was way faster than my CVPI. Funny thing is, I was able to keep on him being he had no idea how to take a corner, and believe me, the crown vic cant handle for s***.\n\nThe new Ford Taurus interceptors are alright, our dept has the front wheel drive(sigh) V6 version. They have 289 horses, and they get up and go just fine. Thing is, I will use that power for getting to medicals, domestics, and other hot calls god knows how many times more than just a handful of pursuits of vehicles.\n\n",
"It is not about having the fastest car. It is about terrain, knowing the roads, and having a car that can handle the roads.\n\nCrown Victorias have V8's geared real high. They don't accelerate particuarly fast, but they do 100+ mph no problem. The same goes for the Impala, with the 300 horsepower V6. If someone tries to run during a traffic stop, in say a 400 horsepower Mitsubishi EVO, well they may easilly hit 140 before the cop can (interstate chase). However road conditions, traffic, and driver skill all play a part in the chase. The crown vic/impala will lose ground at first, but police officers are trained for high speed driving, and can easilly reach 130+ speeds and at least maintain contact with the vehicle. \n\nJust staying in front of a cop in a chase isn't going to mean you can escape, you must lose them, and despite the fact that your car may be faster than a police interceptor, it doesn't mean that it can lose one. \n\nOn a whole different note, you cannot outrun a police radio.\n\nAnd on another, different note... Dodge Chargers and [SHO Package] Taurus Interceptors can push over 400 horsepower, RWD or AWD. You'd have to be a damn fool to think you could outrun these cars. ",
"They have helicopters",
"They do.\n\nThey call them helicopters.\n\n",
"Police cruisers are more like trucks in car clothing, built for heavy-duty and low maintenance. That's why the Crown Vic has been the preferred fleet vehicle for taxis and police forces for over a decade. They can be modified to go faster, but the Interceptor comes with a heavy-duty driveshaft that I understand can fail at speeds over 135 because of the heavy rotating mass.",
"* car chases are rare\n* in most cases, traffic, route, conditions and skill make top end speed irrelevant\n* the police car is not alone...no car is fast enough to outrun a radio",
"we do have a few supercars here but mostly gifts. In general the police use crowd tactics and try and avoid chasing criminals to avoid the possibility of accidents. If it's a fast car and a good driver then its handed over to the chopper.",
"Because there is not a car made that can outrun their radio..."
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1pa4v8 | why didn't the usaf intervene during the battle of mogadishu? | It would've been very easy for them to turn the tide. Why didn't they? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1pa4v8/eli5_why_didnt_the_usaf_intervene_during_the/ | {
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"Because conducting airstrikes in the middle of an extremely crowded urban area would have been an absolute PR nightmare and jeopardized the entire mission there. Bear in mind that at the time it wasn't at all clear that they'd soon be withdrawing altogether, so outraging the entire population of Somalia wouldn't have been done lightly. ",
"Doc Daneeka makes a fine point regarding the risks of collateral damage, but the better note is that the Air Force lacked the capacity. US Central Command requested that AC-130s and A-10s be made ready to provide support, but President Clinton refused that request because it would've meant forward deploying additional assets in Somalia, and Clinton did not want to expand the US' footprint in Somalia. End of the day, the US Air Force did all it could, but it didn't have what it needed."
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38i2uy | duty free shops | What incentive does a country have to allow duty free shops if they can't earn tax revenue off it? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/38i2uy/eli5_duty_free_shops/ | {
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"You have a customer who wants to buy, say, some alcohol which they will drink in their destination country after their journey. If they buy it duty-free in the country they're leaving, it's now a shop in that country making profit on the sale and that country's government collects taxes on that profit instead of the destination's government.\n\nMore generally, it's an extension of the principle that you don't charge duty on goods which are exported. If you did, those exported goods would be subject to two lots of duty (the country of origin and the destination), so the exports wouldn't be competitive with local products. It's better to have a large successful exporting business generating lots of jobs and taxable profits than to collect duty on a much smaller volume of exports from a less successful business."
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8km7f7 | if there's anything bad with jehovah witnesses? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/8km7f7/eli5_if_theres_anything_bad_with_jehovah_witnesses/ | {
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"I'm not religious at all so this may not be the answer your looking for. I've know many Jehovah's witnesses in my life and have no problem with them but lots of people consider them to be cult like, if you look at some of their rules you can see how it could be considered a cult. If your already nervous about it maybe you should wait a while to make your decision ",
"Parts of their doctrine cause them to refuse blood transfusions and other medical procedures, and they actively shun former members and people who refuse to convert often cutting people off from their families and friends after they convert if those people do not also convert, or after they have left the faith if their family and friends stay. These are seen a major, cult like behaviors by most people. \n\nSome also take issue with their refusal to serve in the military, police, or salute the flag/do other patriotic activities. But these are much more minor objections that most do not care about, though it did give them a very bad reputation during the world wars.\n\n",
"My wife had a friend who was JW, her and her husband wanted to hang out with us. I'm a very essoteric Christian and I wanted to have a legitimate conversation about our beliefs. So we started having them over on Tuesday nights to have a little meeting with just the four of us. The first night was good and we had good debates on the subjects. Then he got really preachy and tried to take over and subtly convert us. I called him out on it and in so many words told him that we would never convert but I liked the conversation but not being told what to do. That's what it became too, him just telling us what to do, and that won't ever work on me. I distill the religion out of Christianity and make it into more of a philosophy. Also, I will always refuse to have the \"I'm right, you're wrong\" mentality, God judges and knows people's hearts, that is never your job. So, he didn't like that these meetings weren't us trying to convert and we never saw them again even though my wife and her were really good friends. I think the church told them to stop seeing us, they're very culty like that."
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y591q | why do things like stone, cloth, wood etc. change colour when it comes into contact with water? | Just something I've always wondered but never got around to finding out the answer. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/y591q/eli5_why_do_things_like_stone_cloth_wood_etc/ | {
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"When light hits an interface between two media, it has a chance of scattering. This chance is dependent on the angle of incidence (which we can ignore for simplicity's sake), and the difference in indices of refraction. The bigger the difference, the more scattering there is.\n\nSo when light hits the fibers in cloth, it scatters a lot, because fibre has a very different index of refraction than air. However, when the cloth is wet, light goes through 3 media instead of 2. First it hits the air/water interface - and the difference in indices of refraction is smaller here than between cloth and air - then the light hits the water/cloth interface - once again the difference is smaller. So the end result is that there is less total scattering, since each interface involves two media that is more similar in indices of refraction. So less light scatters off these surfaces and back to your eye, so the object appears darker.\n\nThis also means that more light is _transmitted through_ the material. This can be readily seen, and exploited, in wet t-shirt cont- uh... Go to bed, it's bed time."
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6svgj9 | why do some roads sound different than others? | For example, I-75 in Michigan has a louder sound than I-75 in Ohio. I know that is because of different agencies/contractors using different materials, but is it the composition of the material, how it is laid down, its age, or some other factor? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6svgj9/eli5_why_do_some_roads_sound_different_than_others/ | {
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"it's a combination of how hard it is and the texture of its surface. age can affect both, especially with different environmental factors in different areas"
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da3j8a | why some pills like nitroglycerine need to be desolved under tongue | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/da3j8a/eli5_why_some_pills_like_nitroglycerine_need_to/ | {
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"They don't have to, but for the purposes they're used for, relieving chest pains, the quicker the release of the medication, the better. Sublingual administration (under the tongue) is one of the fastest ways to administer medications outside of establishing an IV or giving an injection."
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5jltkh | why isn't space always full of light? | "Visible light is a form of electromagnetic (EM) radiation, as are radio waves, infrared radiation, ultraviolet radiation, X-rays and microwaves. Generally, visible light is defined as the wavelengths that are visible to most human eyes"
Given that there are so many stars that have been sending light in every direction for 13.5 billion years (or whatever it is) how is space completely black? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5jltkh/eli5why_isnt_space_always_full_of_light/ | {
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"And you see these stars as... points of light. There's a lot of them once you get away from the Sun's glare. And in between them is... nothing. \"Filled with light\" is merely a metaphor - you can only see sources of light or something that reflects light. Emptiness - which space is for 99.99999999999% or so - is neither.",
"It is very full of light. Problem is that you only see the light traveling towards your eye in front of you. There is a ton of light moving right in front of your nose that you can't see because it isn't going into your eye.",
"Imagine you're part of a large group of people huddled together. People are faced in random directions and are not particularly aligned in any way. \n\nNow imagine that everyone starts walking directly forward from whatever direction they're facing. \n\nNow imagine a 5 foot wide wall. If the people start right next to the wall, there's a good chance that a lot of the people will hit the wall. If the wall is 100 yards away, a significantly smaller number of people will hit it. If the wall is a mile away, you likely won't have anyone hit it. If the wall is on the other side of the country, the odds of anyone hitting it is practically zero. \n\nNow replace the people with photons and the wall with your eye, and that's why space is dark. \n\nYour eyes are used to the number of photons that it is being hit with from the sun on any given day. Some of these photons are coming directly from the sun, but most are bouncing off of something else first. They'll be bouncing off of trees and clouds and the ground and literally everything else you can see. \n\nIn space, you'll still get roughly the same number of photons hitting your eyes directly from the sun, but not from those other sources bouncing light. So the number of photons hitting your eyes is much much smaller. \n\nAnd as for light from other stars? Yes, the sheer number of them makes it seem like you should be getting pelted by a near infinite number of photons, but the stars are so far away that the number of photons that hit your eyes is tiny. The number is so much smaller than what we are used to that your eyes simply aren't sensitive enough to get usable information from them. ",
"I'm surprised nobody has mentioned Olbers' paradox. It asks the question \"if every point in the sky eventually ends in a star or galaxy (or similarly bright object) why isn't the sky fully bright all the time?\"\n\nThe answer is because: \n\n1. There are objects so far away light from them hasn't had time to reach us yet.\n2. The universe is expanding, not static, so there are also some objects so far away the expansion will prevent their light from *ever* reaching us.\n3. Light follows the inverse-square law, so objects whose light *could* reach us but are very, very far away will become increasingly dim because most of the photons aren't hitting your eye.\n4. In addition, light that travels a long way through expanding space will lose much of its energy, eventually shifting down into infrared.\n\nAdditionally, there is nothing in space to scatter the light travelling through it in such a way that space would be lit up as the sky on a planet would be. Although technically, all of space in every direction is actually glowing in the microwave spectrum. This light is known as the cosmic microwave background, and it is the remnants of the light released when the universe became transparent to photons around 380,000 years ago. The CMB itself is a highly magnified image of the original quantum fluctuations that eventually became the large scale structure of our observable universe."
]
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[],
[],
[],
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] |
|
5gv2mr | the patterns seen from lights with glasses off. | When I have my glasses off (I have a -6.5 prescription) and look at a light, I see a pattern in the light. The light appears as a bigger area of the same color, but with a pattern. This seems to be exaggerated when in a dark area with smaller lights (think led on a TV in a dark room).
What is this pattern, and why is it structured the way it is? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5gv2mr/eli5_the_patterns_seen_from_lights_with_glasses/ | {
"a_id": [
"davbdog"
],
"score": [
5
],
"text": [
"Behind your pupil and iris of your eye, there is a clear disk-like structure called the crystalline lens. This lens is connected to muscles that stretches the lens so that we can change our focus from far away to close.\n\nOn both sides of the crystalline lens at the center, there is a Y-shaped suture/line that forms as the lens develops. This can form an asterisk-like or other shapes: _URL_0_\n\nNormally, if you have normal vision or are wearing glasses, you don't see these as the light perfectly focuses to a single point on the light sensing back of your eye (retina).\n\nHowever, since you are nearsighted, without your glasses, most of the light doesn't focus to a point. Nonetheless, some of the light can go through these sutures (which act as a different focusing lens compared to the whole crystalline lens) and focus to a point, forming the patterns you see. Only a small amount of light manages to do this which is why you usually see them easier in darkness."
]
} | [] | [] | [
[
"http://www.oculist.net/downaton502/prof/ebook/duanes/graphics/figures/v1/071b/005f.gif"
]
] |
|
25oqfc | how does the wii u manage to stream to two screens without latency and lag? | And the fact that it's last gen... makes no sense. [I own one btw] | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/25oqfc/eli5_how_does_the_wii_u_manage_to_stream_to_two/ | {
"a_id": [
"chj9fg4"
],
"score": [
2
],
"text": [
"1) the processing for the Wii U is inside the console itself, not the remote/controller. The streaming to the TV is (from an electrical engineering standpoint) free.\n\n2) the streaming of visual output from the console to the Wii U remote screen is done via a slightly proprietary H264 codec (similar to what Youtubes etc. use), highly compressed and at low latency (the Wii U being able to decompress it really fast)... aka the screen is updated/rendered on the console part and sent to the remote lickety-split."
]
} | [] | [] | [
[]
] |
|
8pn3md | why does bread stop expanding while it bakes? | Similarly how does it "know" when to start turning brown? Watching time lapses of bread baking it inflates for a while, stops, then gets the golden brown outer color. Why does this happen? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/8pn3md/eli5_why_does_bread_stop_expanding_while_it_bakes/ | {
"a_id": [
"e0cibyx",
"e0cjwoo"
],
"score": [
16,
2
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"text": [
"Bread expands because the yeast in it is burping out gasses as it eats sugars. \n\nWhen you cook bread, the yeast dies.\nDead things can't eat. \nSo the yeast stops eating sugar, thus it stops burping.\n\n\nThe browning happens when it reaches a certain temperature. It's called a maillard reaction. \n This Temperature is higher than it takes to kill the yeast. \nSo the bread will stop growing, and then browns.",
"That browning \\- which I believe is a form of the Maillard reaction \\- happens (or happens much faster) without the presence of water. I believe what happens is that the steam evaporating from the bread suppresses the reaction at first, but as the water either evaporates or gets incorporated into the bread's structure you see more browning. \n\n\nIn fact, this is an important variable for how the bread's density comes out. If your oven is too dry, the outside of your bread can brown and harden, which prevents the CO2 bubbles from expanding. You wind up with dense bread. Some professional bakers use ovens that can inject steam in the early part of the bake exactly to delay this. This is also why it's common to slice the top of your loaves \\- it gives the loaf more ability to expand as the crust hardens."
]
} | [] | [] | [
[],
[]
] |
|
46a2s0 | why do some countries require tourist visas if you're from specific countries? | [deleted] | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/46a2s0/eli5_why_do_some_countries_require_tourist_visas/ | {
"a_id": [
"d03k8pc"
],
"score": [
2
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"text": [
"If you are from a rich and/or friendly country, you a generally considered less likely to cause trouble, and have little trouble getting visas. People from poorer countries are more of a danger to stay illegally, and typically have to show that is not the case to get visas.\n\nInternational relations play a role, too. After 9/11, the US upped their security measures for foreigners. Many countries took offense, and upped their entrance requirements for US citizens.\n\n > And is the point of the visa to take care of the tourist load on the country's infrastructure?\n\nUsually not. Tourist are a net economic plus, most countries want as many as possible.\n\nWhat they don't want is criminals and people who enter as tourist but plan to stay indefinitely and work illegally.\n"
]
} | [] | [] | [
[]
] |
|
besk80 | why are cherry blossom trees different in germany from the ones in japan although they come from the same source? | According to various sources, TV Asahi in Japan planted Sakura (Cherry Blossom) trees in various cities in the west.
But, the Sakura trees in Germany are much bigger and the petals of the flowers are much more pink. The ones in Japan and China are more white than pink.
Any idea why is that? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/besk80/eli5_why_are_cherry_blossom_trees_different_in/ | {
"a_id": [
"el88mdc",
"el8d43d"
],
"score": [
6,
3
],
"text": [
"In Washington, Japan sent 12 different species of cherry trees [[ref](_URL_0_ )].\n\nIt's unclear what species was planted in the location you're looking at, but the notion that all Japanese cherry trees are the same is mistaken.",
"There are different varieties of blooming cherry trees. Their blossoms can be different colors and sizes, and they can bloom earlier or later in the season.\n\nI visited the National Arboretum in Washington DC and they have many different varieties.\n\n_URL_0_"
]
} | [] | [] | [
[
"https://www.nps.gov/subjects/cherryblossom/history-of-the-cherry-trees.htm"
],
[
"https://dcist.com/story/19/03/28/peak-bloom-may-be-fleeting-but-it-lasts-a-little-longer-at-the-national-arboretum/"
]
] |
|
7at3xu | how come the electricity doesn't conduct through the person getting tased to the people supporting him during taster training? | For example, in this video, _URL_0_ | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/7at3xu/eli5_how_come_the_electricity_doesnt_conduct/ | {
"a_id": [
"dpckgo2",
"dpckizk",
"dpckjke"
],
"score": [
8,
2,
2
],
"text": [
"Elektricity is lazy and always takes thé shortest route back. Meaning from pin 1 of the taser to pin 2 of the taser",
"Electricity will take the path of least resistance to complete the circuit. The two darts connect to the person being \"shot\" and the electricity will travel between the darts. It would be a longer, and more resistive, path for the electricity to travel into the other people.",
"Tasers shoot two little electrodes into the body (ideally). One is positive, one negative. The high voltage between them causes a current pulse in the body. It doesn't all go on a direct path between the electrodes, but it mostly does. After all, that's the lowest resistance path, in general. \n \nSome current could flow through the person's body, through a helper's body, and to ground through their shoes. But that's a lot higher resistance, so relatively little current is going to flow that way. \n \n**TL;DR:** Electrical current will flow along all available paths, with the most current going along the lowest resistance paths."
]
} | [] | [
"https://www.youtube.com/watch?v=FsXCJl0hh34"
] | [
[],
[],
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|
1ezin2 | how does a venus flytrap work? | I can't get my head around a plant that can trap and eat insects without a 'Brain'. How can it tell the difference between an insect and a leaf or even a strong wind?
Can someone explain it to me? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1ezin2/eli5_how_does_a_venus_flytrap_work/ | {
"a_id": [
"ca5awfc"
],
"score": [
13
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"text": [
"It responds to stimulation of hairs inside its trap, which causes it to close (the signal is transmitted via an action potential, similar to nerves in animals). This step can be triggered by any direct contact. I used to have one in a pot that you could poke with a stick & cause it to snap shut. [Here's a gif of someone using a skewer to do so.](_URL_0_)\n\nHowever, the digestion process only takes place if the hairs are stimulated once the trap has already closed, so this requires something alive & moving to continue to stimulate it, so the wind or a leaf probably wouldn't work in most cases.\n\nThese functions don't require a brain, as they're more like reflexes than conscious actions. The plant doesn't choose to close it's traps, it just responds to stimuli.\n"
]
} | [] | [] | [
[
"http://upload.wikimedia.org/wikipedia/commons/9/9d/Dionaea_muscipula_closing_trap_animation.gif"
]
] |
|
3kog67 | why is it typical to see different punt formations in college versus the nfl? | In college you often see a handful of players about halfway between the punter and the line of scrimmage. Why is this prevalent in college and not the NFL? What is the strategy behind it? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3kog67/eli5_why_is_it_typical_to_see_different_punt/ | {
"a_id": [
"cuz5hnd"
],
"score": [
5
],
"text": [
"There are different rules for the \"ineligible player downfield\" penalty. In the NFL, only the players at the side of the formation, known as gunners, are allowed to run toward the punt returner as soon as the ball is snapped. All the people crouching along the line of scrimmage can't go more than a yard forward until the ball is kicked. \n\nUnder NCAA rules, the linemen can run toward the punt returner right after the snap. As a result, some of the linemen take advantage of this and run forward after the snap. The players near the punter in the \"shield punt\" formation can block any defender who managed to get past the offensive line. \n\nSo, to answer your question, NFL rules make it so the punting team probably needs to use gunners on the sides of the field, while NCAA rules allow the linemen to do the running."
]
} | [] | [] | [
[]
] |
|
9pbrfp | how does thermogenesis in the body work when eating? | Does it have a major effect on metabolism or not really? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/9pbrfp/eli5_how_does_thermogenesis_in_the_body_work_when/ | {
"a_id": [
"e818mal"
],
"score": [
2
],
"text": [
"Depends what kind of food. That’s why eating too many eggs won’t cause weight gain as easily as eating too many cookies."
]
} | [] | [] | [
[]
] |
|
a8p01c | why does water vapour come off of stuff that you pull out of the freezer? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/a8p01c/eli5_why_does_water_vapour_come_off_of_stuff_that/ | {
"a_id": [
"ecchjoy",
"ecd6u59"
],
"score": [
5,
2
],
"text": [
"The frozen item chills the air around it. This causes the water vapour already in the air to precipitate out as fog. So, the vapour isn't coming off the item, it's coming from the air around it.",
"When a freezer is cool, the air within it cools off as well. This causes the air inside the freezer to become very dry. As soon as you open the freezer, air (with the room or ambient humidity) rushes in. This is nature’s way to achieve equilibrium in humidity levels. When cold dry air meets warmer, moist air, they mix to form a small fog/mist like concoction. This is what is typically observed as coming off cold/frozen items. "
]
} | [] | [] | [
[],
[]
] |
||
1nl02g | why if i sleep with the fan on i wake up with a sore throat? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1nl02g/eli5_why_if_i_sleep_with_the_fan_on_i_wake_up/ | {
"a_id": [
"ccjj3ce",
"ccjm2bv",
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"score": [
10,
2,
4
],
"text": [
"I think its because you keep air circulating that it will become dry, as a result when you breathe in it will dry out your throat, making it sore in the mornings, take a glass of water to bed with you for just before you fall asleep and as you wake up, it will make a difference, alternatively turn the fan off and sleep with fewer sheets.",
"Just throwing this out there, clean your fan. Dust builds up super fast. Blow your nose before going to bed. Vacuum your sheets and pillows regularly. And stay hydrated.",
"forget dry throat, if you were in Korea you'd wake up dead!"
]
} | [] | [] | [
[],
[],
[]
] |
||
26ali8 | i've noticed that most cultures in the world have loose and flowing clothes, how come we've come to accept "western" clothing | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/26ali8/eli5_ive_noticed_that_most_cultures_in_the_world/ | {
"a_id": [
"chp7i7e"
],
"score": [
2
],
"text": [
"Colonialism. Specifically British colonialism. "
]
} | [] | [] | [
[]
] |
||
8jxk49 | what is an electric boogaloo? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/8jxk49/eli5_what_is_an_electric_boogaloo/ | {
"a_id": [
"dz38gdd",
"dz3j0kd"
],
"score": [
48,
3
],
"text": [
"It's a reference to the 80's movie *Breakin' 2: Electric Boogaloo*, the sequel to the breakdancing film *Breakin'*. The was widely considered to be awful, and the subtitle \"Electric Boogaloo\" is now used by people to denote a needless or subpar sequel that probably shouldn't have been made. *The Passion of the Christ 2: Electric Boogaloo*, would be an example.\n\nThe actual term \"Electric Boogaloo\" was a type of funk/hip\\-hop dance featured in the movie.",
"It is the only thing high school students needed to study to get a five on the AP English Language and Composition exam this year :\\)"
]
} | [] | [] | [
[],
[]
] |
||
5ppui9 | why do some sodas (like coke) produce a lot of foam when it's poured into a cup, from say, a can, while other sodas (like sprite) don't produce nearly as much? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5ppui9/eli5_why_do_some_sodas_like_coke_produce_a_lot_of/ | {
"a_id": [
"dcsvvah",
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"dctdhi4"
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"score": [
24,
17,
3,
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"text": [
"the most important factor in how \"foamy\" a soda acts is which of its ingredients raise or lower surface tension. Aspartame promotes the formation and persistence of bubbles, as do certain preservatives.\n\nThe combination of multiple foam-promoting ingredients and circumstance is why Diet Coke reacts so energetically with Mentos candy.",
"I know this!\n\nThe answer is because sprite, unlike coke, contains citric acid, which lowers the surface tension of the fluid making foam less likely to forms and quicker to dissipate when it does.\n\nYou can create this effect yourself with Coke or Diet Coke by pouring the beverage over a lemon wedge placed in the cup. The lemon oil and citric acid from the lemon prevent foaming.",
"It also has to do with how cold the beverage is. The bubbles are CO2, which are dissolved into the liquid and released as they're agitated or at nucleation points. The colder the liquid, the harder it is for the CO2 to come out of solution. \n\nTry it yourself, take two cans of coke, and put one in a cold fridge overnight and leave one at room temp. Then pour both into separate cups and observe the foam production.\n",
"Well, that's because Coke needs an alcoholic beverage, as far as that russian explains: _URL_0_"
]
} | [] | [] | [
[],
[],
[],
[
"https://mad-rabbit.com/a-russian-trick-to-use-the-coca-without-foam/"
]
] |
||
3ooam8 | how come each language seems to have 10 digits? | Well, I'd imagine not ALL of them. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3ooam8/eli5_how_come_each_language_seems_to_have_10/ | {
"a_id": [
"cvz0qab",
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"score": [
5,
3
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"text": [
"The man reason that so-called \"Arabic numerals\" have risen to prominence in almost every language uses a base-ten counting system, which was originally used with those numerals. Some languages still have their own distinct numeral systems, especially (and perhaps ironically) Arabic, and I believe many of the languages of India, but Arabic numerals are increasingly being used in place of or alongside them.\n\nWhy the base ten counting system became so popular is that the Indian mathematicians who invented positional notation and the digit for zero used base ten, and that's how everyone else learned it. Positional notation is vastly superior for doing calculations compared to non-positional notation (Roman Numerals being a prominent surviving example) so uptake was pretty well universal.\n\nFunny enough, even though our numerals are base ten, our languages still reflect the time before base ten became the world standard. Most of Europe once used a base-twelve counting system, which is reflected in languages like English who have special words for \"eleven\" and \"twelve\" instead of calling them things like \"oneteen\" and \"twoteen.\"",
"Mostly because we have 10 fingers, right?"
]
} | [] | [] | [
[],
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] |
|
1fauz1 | how are pregnancy test never 100% accurate? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1fauz1/eli5_how_are_pregnancy_test_never_100_accurate/ | {
"a_id": [
"ca8h1uu"
],
"score": [
3
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"text": [
"So first there is the obvious \"I took it too soon.\" This comes from the fact that the placenta makes human chorionic gonadotropin, which is the hormone detected by the test. If you take it before it is high enough to be detected, the test will fail.\n\nAll tests have to pick a line at which above a value is considered positive. The trick is to have it high enough so that you don't get false positives, but not so high that you get false negatives. Now you might think, \"but shouldn't it just be positive if the hormone is there and negative if it is not?\" But it is not that simple. All tests have background sensitivity that can cause them to be picking up a reading. The trick is to make that threshold high enough so only true positives are picked up.\n\nSince not every person, placenta, and urine sample is 100% the same, we cannot be 100% sure. \n\n\nAlso tests can be defective. \n\nEDIT grammar"
]
} | [] | [] | [
[]
] |
||
qfahg | high pressure systems and low pressure systems | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/qfahg/eli5_high_pressure_systems_and_low_pressure/ | {
"a_id": [
"c3x5wzg"
],
"score": [
6
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"text": [
"Hi, I will answer this properly since it hasn't been done so far...\n\nThe H and L on a weather map do stand for areas of High and Low pressure. By low pressure they mean the air has a natural tendency to rise due to several possible effects. These effects are normally either intense heating by the sun in tropical or inland regions, causing the air to rise thus reducing air pressure. Or a phenomenon called ''The polar front theory''. It is very complicated to try to explain and has never been fully done, but basically it happens when air mixes around the mid to high latitudes, this forms what you know as warm and cold fronts.\nAir that rises releases energy by losing temperature and condensing water vapor (cloud), this fuels bad weather such as storms or in the more normal lesser circumstances cloudy and rainy weather due to the water vapor condensing out of the air.\n\nHigh pressure systems are the opposite. In these the air has a tendency to descend. This creates more settled weather with air re-absorbing condensed water vapor (cloud) creating clear sky's and light winds. High pressure systems are secondary to low pressure systems, they normally are formed because of a low pressure system.\nThe air rising out a low pressure system has to go somewhere, it will travel hundreds of kilometers across the earth in the upper atmosphere to then descend far away, creating a High pressure system.\n\nAs low pressure systems are generated in predictable areas (the equator due to the suns heating, and around 45 degrees of latitude due to the polar front theory) so are High pressure systems. Here is a link [_URL_0_] that shows how low and high pressure systems control the entire planets weather and climate.\n\nSource: Me (A university meteorology student)"
]
} | [] | [] | [
[
"http://ridge.icu.ac.jp/biobk/deserts.gif"
]
] |
||
2n9aji | preferred stock | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2n9aji/eli5_preferred_stock/ | {
"a_id": [
"cmbmmj5"
],
"score": [
2
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"text": [
"There's more than 2 attributes to a stock. There's common vs preferred sure, but there's also voting vs non voting, an ones that guarantee a dividend vs those that don't, along with other attributes.\n\nPreferred shares are commonly paired with a clause that guarantees a dividend. The fact that the shares are preferred is what forces the company to pay the garunteed dividend FIRST, before it pays any common shareholder dividends.\n\nSay the company can pay $10,000 in dividends and it has 2 shareholders. One would assume that it would be fair to pay each person $5,000 and that would normally be the case.\n\nBut one of the shareholders holds preferred shares that guarantee him a $6,000 dividend that year. So he gets $6,000 and the other guy only gets $4,000.\n\nIn a second example, the guarantee states the preferred shareholder should receive $11,000 a year. But only $10,000 in dividends can be paid, so the preferred shareholder gets all of it and the common shareholder gets none. (the remaining amount owing to the preferred shareholder can sometimes roll into the next year).\n\nSo basically when it comes time to divide up the total dividend payment a preferred share allows you to take your portion first. If your portion is just an equal share then this preference is meaningless, but if your portion is more than an \"equal share\" then you are allowed to take your full portion, because you are preferred.\n"
]
} | [] | [] | [
[]
] |
||
dvl88i | with deepfake voices now sounding almost indistinguishable from human voices, why do computer voices (tts, google maps, etc) still sound like garbage? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/dvl88i/eli5_with_deepfake_voices_now_sounding_almost/ | {
"a_id": [
"f7dd1fl",
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5
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"text": [
"Because they're not deep-fake voices. \n\nThey're deliberately kept out of the uncanny valley by remaining obviously computerized. That way, nobody gets weirded out by an almost human voice.",
"There are a couple of factors at play. First off, think of the sheer volume of things that these voices have to figure out how to say, on the fly. Travel through America and you'll run into all sorts of oddly named streets. Then take into account how much local dialect plays into street names. For example I've spend most of the year in Nashville for work, and drive by the \"Grand Ole Opry\" on a daily basis. Siri insists on pronouncing it \"Oo-Pree\". With that kind of variety, it's going to be more focused on being easily understood, than sounding human. \n\nSecond, we don't want it to sound human. A truly human sounding voice would be off-putting. Meanwhile the fancy computer voice on Star Trek didn't sound human, it sounded like a computer. If Alexa talks to me like a human, then I don't feel special. Sound slightly like a computer, and I feel like I'm living in the future."
]
} | [] | [] | [
[],
[]
] |
||
7eibjh | how exactly do the pens that claim to have special ink help prevent check fraud? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/7eibjh/eli5_how_exactly_do_the_pens_that_claim_to_have/ | {
"a_id": [
"dq53zzr",
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"score": [
3,
3
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"text": [
"Without specific details on the pens in question, some guesses will be made.\n\nI will assume the pen is using an ink with a dye that chemically reacts/binds with the paper, leaving a mark that can not be erased. This prevents the value of the check from being altered, as a properly written check would show a different word and numerical value, and could easily be identified as altered, along with preventing the addressee from being changed.",
"It helps prevent check washing. \n\nBy soaking a check in a solvent like acetone or rubbing alcohol, you can remove what was written with a pen without altering the rest of it. This allows a criminal who has stolen uncashed checks to remove the payee and replace it with their own name and alter the amount.\n\nA special ink can bind to the paper as strong as the printed ink, making it difficult to remove with erasing the entire check."
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51gi8c | problems with cryopreservating humans | I know some very very basic stuff, like the problem of blood expanding when frozen, or the diffiulty of unfreezing, but what are the major problems that keep this technology from being used? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/51gi8c/eli5_problems_with_cryopreservating_humans/ | {
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" > but what are the major problems that keep this technology from being used?\n\nMainly because we don't have any good way of bringing someone who has been pumped full of antifreeze back to life. Even if we can prevent cells from forming ice crystals and breaking as they expand, turning the person to mush upon thawing, we still have some recently thawed dead person.\n\nWhy bother so much when in the best case all you can get is a relatively undamaged corpse?",
"Freezing a human results in the water in their cells to form crystals and expand. This results in the cell bursting. \n\nCryopreservation supposedly removes the water from the body and replaces it with cryoprotectants, which don't crystallize at low temperatures. This allows most of the cells to remain intact.\n\nOne problem is we know of no way to replace those cryoprotectants with water again and restore life to the individual. ",
"[Cryonics](_URL_1_) is the word you want. Its specifically the act of cryoproserving of humans. Even more specifically, cryopreserving humans who are currently too injured or sick to be helped by modern medicine. The idea is to have them sort of \"time travel\" into a future that may help them. The science is a bit different from simply freezing the bodies, and I'm a bit too ignorant to go into detail. The process is called \"Vitrification\", but the wiki link knows more. \n \nI do know that three major hurdles are preventing Cryonics from becoming a mainstream means of helping patients. \n \n* There is currently no known way to revive cryopreserved patients. So right now the best we can do is store them and pray the technology is created. \n \n* Kinda linked to the first one, since no known method of revival exists we don't even know if we *can* revive the patients as they are now. This is made even worse by the degredation of patients as time goes on. While vitrification does slow down decomposition so that it may as well not be, it has its own ways of damaging tissue through long-term use. Those that have been preserved the longest will have to wait the longest for the appropriate technology to exist, if it comes at all, because of this degradation. \n \n* The public finds Cryonics kind of scary, and the laws reflect that. Vitrification causes the least damage if its performed on living patients, but has been deemed illegal on all but deceased bodies. Other laws may also simply ban Cryonics or even its studies cuz... idk, politicians do dumb things all the time. \n \n[The Cryonics Institute](_URL_0_) is much smarter than me though, so they'll have even more in more detail. \n \nHave Fun, Stay Cool."
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18il6x | how come i cannot control my brain enough for me to tell it to stop doing things that i dislike (e.g. diabetes, where it tells the beta cells do something that is harmful to my body, pimples, etc.)? | Is there a way to fix this? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/18il6x/how_come_i_cannot_control_my_brain_enough_for_me/ | {
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"Is this a real question from a 5 year old because I'm having a tough time deciphering the question. If you are asking \"why can't i control everything that happens in your body?\" then...\n\nYour body is like a car. It's a machine built with parts made to do specific jobs. You have a bit of control over the machine, like the steering wheel, gas pedal, brakes, etc but you don't actually have specific control over the entire engine. It \"just works\" with the minimal input you give it. \n\nSome things like headlights can turn on themselves when it's dark automatically in case you forget but you could override them and turn off or on if you want. \n\nSometimes a part breaks, like the speedometer. Even though the car still runs and works, it's really difficult to tell how fast you're driving now. You might get in trouble and get a ticket or even worse, crash if you're not careful. You can try to replace or fix a broken part but sometimes you can't.\n\nThings like acid rain, rocks or salt from the road, or the sun can damage the pretty paint and make it not so shiny. You can't control those things since they are foreign bodies.",
"OK well the brain doesn't control everything in your body. Your DNA does, in fact your DNA controls your brain. Most problems caused in the body are due to problems in your genetics, which cant be fixed with current technology. Also most of your functions controlled by the brain are controlled by the unconscious portion of your brain."
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bi8xx4 | why do orchestras have multiple players with the same instrument? | Is it because they are playing slightly different notes or a different pace? Or is it to amplify the sound and effect? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/bi8xx4/eli5_why_do_orchestras_have_multiple_players_with/ | {
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"It amplifies the sound and effect. If you had one person clapping to a beat compared to fifty it would give it alot more umpf ya dig.",
"Orchestras were around before microphones.\n\nBy having multiple instruments playing the same part you get a louder sound so the whole audience hears the music.\n\nAnd even larger numbers of the same instrument means that you can have different parts being played by different parts of the section and they're still heard.\n\nMusic for smaller gatherings generally only had a single instrument per part played - like chamber orchestras which were often just four musicians.",
"A couple of reasons:\n\nThe more instruments that are playing, the louder the sound will be - so if you go back before the invention of modern amplification, if you wanted to make enough volume to fill a large auditorium, you needed many instruments.\n\nYou can also use this to balance the sound from different instrument sections - if you have one musician playing a loud instrument, you may need multiple musicians playing some of the quieter instruments to create an equal volume and be heard clearly.\n\nNot all musicians will be playing the same piece of music at the same time - with many more complicated pieces of music you may have a large group of the same instrument split into two or more groups and playing different parts."
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dlauwt | why does taking the derivative of a function give you the slope? | So I understand the limit definition of a derivative, it's like the slope formula:
f(x+h) - f(x)/h
as the h gets closer and closer to zero the difference between f(x+h) and f(x) becomes super tiny, until you're basically finding the slope of a single point. Now the line is a tangent.
[_URL_0_](_URL_1_)
Here's what I don't get:
Why does the derivative of x^(3) \- 5x^(2) equal 3x^(2) \- 10x? How did we get from the limit definition to this weird method of multiplying the coefficient by the exponent, and then subtracting 1 from the exponent? Why are those steps even related to taking the derivative?
Thanks. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/dlauwt/eli5_why_does_taking_the_derivative_of_a_function/ | {
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"The most useful thing I was ever taught by a math teacher was that if you don’t know if/how something works, try it with simpler numbers. Take the equation y = 6x. Obviously your slope is 6, but how did we get there? You’ll notice that in every main function equation the slope (often referred to as “m” is attached to your x value) take for instance slope-intercept form: y = mx + b and point-slope form: y - y1 = m(x - x1). The expression is always x time slope, so how do you isolate slope? you take out an x from the value by division (dividing by an x will lower your exponent by 1) the part about multiplying by the original exponent is a bit more complicated though.",
"In particular, the derivative of x^(3) \\- 5x^(2) equals 3x^(2) \\- 10x because it's what you get when you apply the limit definition.\n\nf(x+h) - f(x) =\n\n= (x+h)^(3) \\- 5(x+h)^(2) \\- (x^(3) \\- 5x^(2))\n\n= x^(3) \\+ 3x^(2)h + 3xh^(2) \\+ h^(3) \\- 5(x^(2) \\+ 2xh + h^(2)) - x^(3) \\+ 5x^(2) (expanded terms)\n\n= 3x^(2)h + 3xh^(2) \\+ h^(3) \\- 5x^(2) \\- 10xh - 5h^(2) \\+ 5x^(2) (x^(3) terms cancel)\n\n= 3x^(2)h + 3xh^(2) \\+ h^(3) \\- 10xh - 5h^(2) (5x^(2) terms cancel)\n\nSo ( f(x+h) - f(x) ) / h =\n\n= 3x^(2) \\+ 3xh + h^(2) \\- 10x - 5h\n\n....and taking the limit as h - > 0 leaves you with 3x^(2) \\- 10x\n\n & #x200B;\n\nNow let's say you want to do this for any polynomial term, i.e. something that looks like Ax^(B)..... well, plug it in and do it again.\n\nf(x) = Ax^(B)\n\nf(x+h) = A(x+h)^(B)\n\nf(x+h) - f(x) = A(x+h)^(B) \\- Ax^(B)\n\n= A(x^(B) \\+ Bx^(B-1)h + B(B-1)x^(B-2)h^(2) \\+ ... + h^(B)) - Ax^(B) (just expanding the thing in parenthesis)\n\n= Ax^(B) \\+ ABx^(B-1)h + AB(B-1)x^(B-2)h^(2) \\+ ... Ah^(B) \\- Ax^(B) (multiplying through by A)\n\n= ABx^(B-1)h + AB(B-1)x^(B-2)h^(2) \\+ ... Ah^(B) (Ax^(B) terms cancel)\n\nSo ( f(x+h) - f(x) ) / h =\n\n= ABx^(B-1) \\+ AB(B-1)x^(B-2)h + ... Ah^(B-1)\n\n....and taking the limit as h - > 0 will kill all the terms except for the first one, giving you ABx^(B-1)\n\nTo recap, f(x) = Ax^(B) and f'(x) = ABx^(B-1)\n\n....which as you said, is the\n\n > weird method of multiplying the coefficient by the exponent, and then subtracting 1 from the exponent\n\n & #x200B;\n\nNot really an ELI5, but you said you get the limit definition, so this should make sense. Hope it helps.",
"If you do the algebra - actually calculate the limit of \\[f(x+h) - f(x)\\]/h as h goes to 0 for f(x) = x\\^3 - 5x\\^2 ... you will see that it equals the expression that you found using the shortcut. The shortcut is a generalization of the algebra."
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5z9u6c | can the brain really change the function of the body's organs? | Is it possible?
I've read somewhere a while ago (don't remember where) about the brain reassigning the functions of the body's organs to different tasks, such as when one or more of the organs fail to fulfill a certain function. For example, if the Liver is forced to take on the role of one of the failed Kidneys as well as its original function.
If it is real, what is it specifically called? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5z9u6c/eli5_can_the_brain_really_change_the_function_of/ | {
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"As far as I'm aware? No. \n\nYour organs are all super specialized, and so are the cells that make them up. You can't turn a liver into a kidney for the same reason you can't turn a banana into an apple, they're different things. Similarly you can't make something that's designed for breathing do something that isn't breathing.\n\nNow, if a kidney fails, the liver might have to work a little harder to filter out toxins, but it's not going to be another kidney, and really the liver isn't going to change, it's just going to work harder.\n\nYour brain can do a whole lot of stuff, but it can't make one thing out of a different thing. ",
" > For example, if the Liver is forced to take on the role of one of the failed Kidneys as well as its original function.\n\nTo a certain extent, some waste products of the blood are excreted in the bile duct, into the intestinal tract.\n\nThis has nothing to do with the brain or CNS. It happens even in brain-dead persons.\n\nProbably the most important function of the kidneys is to eliminate excess potassium, sodium, phosphate, chloride, and urea nitrogen. Not to mention water.\n\nThese are all very small atoms/molecules. If these are excreted into the intestines, they tend to get reabsorbed there into the bloodstream. So, the liver simply isn't capable of taking over the vast majority of the kidneys' function.\n\n\n\n"
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4gu1lo | what happens as we grow up that makes us stop liking people of this age and instead like people closer to a different age, and why does this not happen for pedophiles? | EDIT: Sorry for any confusion, meant sexually attracted to | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4gu1lo/eli5_what_happens_as_we_grow_up_that_makes_us/ | {
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"Your question seems somewhat confused.\n\nWhat happens as you grow up is you continue to like people of around your own age. As you get older, so do the majority of your friends. Obviously this isn't universally true, and equally clearly being friends with people younger than you doesn't make you a child molester.",
"Morality and social norms keep most people from messing around with people more than a few years younger (for men. Only we really take the hits for being with someone much younger in most situations). Also, since people naturally as they grow up tend to stick by people their own age group (they're more likely to like/think the same as you), you tend to stay away from those who don't fit this. \nNow most of the above has generally nothing to do with pedophilia, because it's not like pedophiles go their whole life hanging around with kids. (To quickly make this clear, I mean ACTUAL pedophilia. That means pre-pubescent. If you're talking about a 20 something hooking up with a 15 or 16 year old that actually has its own name separate from pedophilia, because their body and mind are maturing. I really hate when people clump every person below 18 together) Pedophiles have a distorted chemical profile in their brain; they don't see things the way most do, and typically their sexual orientation to certain body types/ages stay that way their whole life, and it's not something they can change without serious help from professionals and mental fortitude.",
"I wouldn't say anyone stops feeling sexual attraction to, say, a 20-year-old just because they're in their late 40s.\n\nIf anything, what happens is that your upwards age broadens out. To use the late-40s example again: You still find an 18-year-old to be sexually attractive, but a woman of 60 will have more in common with you in maturity and emotional intelligence. It's just less likely that you'll end up with someone significantly younger than you unless it's a paid transaction.",
"On the flip side of this, I have been attracted to 'older' men (late 30s to late 40s) since well before I was legal. I have never felt attracted to anyone my same age as a teenager or in my 20s. I'm relieved to be in my 30s because my choice in men just gets more and more appropriate. I just hope that it changes as I go beyond my 40s someday so I'm not a 75 y/o cougar prowling for men who aren't even middle aged yet o_O"
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1jwoa7 | half life (not the game). 'what' has been covered, can anyone tell me how / why? | Through this subreddit and google, I have read that the 'half life' is the time a radioactive substance will take to decay to half of its initial value.
My question is this: why do 1/2 of the atoms live x, 1/4 live 2x, 1/8 live 3x, etc.
You have 8 atoms. Atoms a,b,c, & d decay in the first week, e & f in the next, g in the next. 'a' lived for one week, 'g' for three weeks. Are they not the same type of atom? If 'a' had been preceeded by 16 atoms, 'g' would have lived 4 weeks. Why? How did 'g' know when to decay? It's not like these atoms are in cahoots with each other - why do identical atoms with the same number of protons, neutrons and electrons last a different amount of time?
I imagine the most obvious answer would that atoms decay at a slower rate when surrounded by similar atoms, but that would lead to a decay rate related to the ratio of surface area vs volume, which it is not.
WHY?! HOW? ELI5!
EDIT: Okay, I am getting close to understanding now, but not quite there yet.
First, I was always stuck on why *half* of the atoms would live a certain amount of time vs others, but that number is arbitrary - we could have called it one-quarter-life and simply measured things by how long it takes for 1/4 of the atoms to decay.
Second, I was thinking of atoms in the wrong way. Paint peels after ten years, milk goes bad in a week, etc, not half of it. This is comparing apples and oranges, of course, because..
Third, apparently atoms have a statistical probability of decaying. That probability is somewhat constant, so if we measure how long it took that probability to decay half of the atoms, DING, there's your number.
Next question for me is this: why do atoms have a probability of decaying rather than just an amount of time they take to 'decay' or fall part like everything else we have in the visible world?
EDIT2: This has been fascinating - the incorrect analogies just as much as the correct ones! The short answer is: Quantum Mechanics. Quantum mechanics says an atom has a probability of decaying, and if you want to know why, go back to school. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1jwoa7/eli5_half_life_not_the_game_what_has_been_covered/ | {
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"Forget about atoms for now.\n\nFill a shoe box with quarters - let's play a game. You know coins have 50/50 chance of being heads and tails. You put these coins into the box, close the lid, and shake it up. You open the lid, and remove any coins showing heads.\n\nEach time you do that, you'd expect to remove on average half the coins - because there is 50% chance they'll be heads. But wait - if you started with 100 coins, you removed about 50 the first time, then 25, then 13, etc.\n\nBut this doesn't result from any coins actually _interacting_ with each other to affect whether they're heads or tails. This is _purely probabilities_. How many coins you actually remove is based on the size of the starting sample - the only thing that's constant is that 50%.\n\nIt is the exact same thing with radioactive decay. After one half-life, each and every atom has 50% chance of undergoing decay. They don't need to communicate with each other, or affect each other, to result in this type of behaviour - it arises due to _chance_.",
"Contrary to what some people have already answered materials don't have a measurable and consistent half life because of the atoms around them.\n\nFor example if I had 5 million atoms of radio active material with a half life of 1 day. After 1 day I would have about 2.5 million atoms left. It doesn't matter if they were in one pack of 5 million atoms to start with, or 5 separate packs of 1 million atoms."
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2457fq | how do so many actors/actresses from successful television shows manage to never have to work again? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2457fq/eli5_how_do_so_many_actorsactresses_from/ | {
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"Maybe theyve moved on from acting. Not all people do one career for their entire life. Especially females, some go and choose to become moms instead of actresses",
"Residuals, investing etc. "
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3mnzfi | why is finding liquid water on mars such a bigger deal than it being in different forms? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3mnzfi/eli5why_is_finding_liquid_water_on_mars_such_a/ | {
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"Life as we know it needs liquid water. Finding liquid water outside Earth makes it more likely life or proto-life might have evolved in Mars, and more generally if liquid water is common in our solar system, it might be common around the universe and increases the chances there is life somewhere else.",
"Liquid water indicates an environment capable of supporting life (at least life as we know it on Earth). Finding liquid water would raise the chances of finding some kind of bacteria or other simple life. This is why we're so interested in the liquid oceans of Saturn's moon Enceladus and Jupiter's moon Europa - they both have subsurface oceans.\n\nEdit: Thanks, /u/kresentphresh!",
"Also, I would add [Percival Lowell's](_URL_0_) reputation would be rehabilitated and other scientists' reputation would be damaged. ",
"As I predicted, the scientifically-illiterate mass media have blown this announcement wayyy out of proportion. This announcement is interesting scientifically, lacks any deeper meaning for the possibility of Martian life.\n\nThe liquid water flows they have found evidence for are:\n\n--Very small.\n\n--Very short-lived and seasonal.\n\n--Possible only because the water has a very high concentration of perchlorates, which makes them toxic to life as we know it.\n"
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6pz88f | why do birds such as geese or penguins have teeth on their tongues? what lead to this? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6pz88f/eli5_why_do_birds_such_as_geese_or_penguins_have/ | {
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"Geese don't have teeth on their tongues. They don't have teeth at all. \n\nGeese have a series of serrated \"teeth-like\" things on their beaks, which are primarily used to grab and rip meat/fish. \n\n[Here is a young goose chomping on my finger](_URL_0_) it's painless, until they start to tug, at which point they can easily rip the skin and draw blood. Though not at this age as his serrations haven't come in fully. "
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44dobm | if the second amendment guarantees the right to keep and bear arms, how are some parts of the usa able to require gun licenses? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/44dobm/eli5_if_the_second_amendment_guarantees_the_right/ | {
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"Literally the first words of the second amendment are \"Well-regulated\".\n\nRequiring a license for something does NOT infringe on the right to have something. We have a right to get married, but it requires a license. \n\n",
"The 2nd amendment isn't specific. For the same reason that not all speech is free (like perjury, speech that endangers people, etc).\n\nAll it says is that in order to maintain a well regulated militia (the well-regulated part can't be ignored), the right to bear arms will not be denied. There is a lot of interpretation that goes on there. SCOTUS leaves it up to the states, for the most part.",
"As a general principle of constitutional law, no right is absolute. Every right is subject to regulation by either the states of the federal government; the question is by what standard we evaluate each proposed regulation in order to determine whether it is permissible or not.\n\nThe highest standard of review is called \"strict scrutiny\", and it applies to rights like the right to free speech. It means that in order for a regulation to pass \"strict scrutiny\" and be permissible under the constitution, it must be justified by a compelling government interest, it must be narrowly tailored to achieve that interest, and it must be the least restrictive means to achieve that interest.\n\nThe lowest level of review is the \"rational basis\" test. This means that the law or regulation must be \"rationally related\" to a \"legitimate government interest\". This is a very low bar, and so long as the law has some kind of relationship to the goal the government is trying to achieve, it will be allowed. Most state laws fall under this level of review, provided they don't involve a fundamental right protected by strict scrutiny.\n\nWith the Second Amendment in particular, the level of review has not yet been firmly defined by the courts, though some have suggested it should fall in between these two levels of review. Regardless, requiring licenses for handgun purchases would most likely pass any level of review."
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c71ljr | how were we able to film the explosions of atomic bombs? i would assume the sheer amount of force would blow any type of camera to dust. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/c71ljr/eli5_how_were_we_able_to_film_the_explosions_of/ | {
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"Because your assumption is wrong. Notice how all the footage of atomic detonations is from far away? Thats because they don’t have unlimited blast radius. You can look at one, and film it, from far enough away that the shockwave will dissipate before it hits you.\n\nThere is very limited footage from camera’s within the lethal radius, and those cameras were placed in reinforced structures, not directly facing the explosion, rather they are trained on a ‘subject’ to observe as it is destroyed, usually at an angle away from the blast.",
"Place the camera in a bunker and have it look out via mirrors. This also protects from gamma radiation since it passes right through the mirror.",
"There are several ways in which the detonations were photographed.\n\nThe first is to do it from a long distance. For any given sized atomic explosion there is a radius at which it is basically safe to be. You can use [NUKEMAP](_URL_1_) to get a sense of this. Add a powerful zoom lens to a camera and you can see quite a lot, even if you are really far away. They're big but not unlimited in size.\n\nThe second is to protect the camera. There are a lot of ways to do this, but one way they used for the first atomic test (Trinity, 1945) was to put the cameras in concrete bunkers, facing up. Then they put 45º mirrors at the top, facing the blast. So the blast might eventually destroy the mirrors (the cameras were interested in the first milliseconds of the bomb or so), but the cameras themselves were safe in the bunkers. [This Twitter thread has pictures of these cameras, and the results of their filming](_URL_0_). Note that these cameras were close enough that they attached them to a \"sled\" so that a tank could later pull up to them, grab them, and go into a safer zone.\n\nThere are other ways to do this. Remember that while nuclear detonations are powerful, they're not infinitely powerful. It's possible to harden things against them, at least at a distance. And cameras and other mechanical devices can be built to survive things (like radiation fluxes) that humans cannot."
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"https://twitter.com/wellerstein/status/988536394330071040",
"https://nuclearsecrecy.com/nukemap/"
]
] |
||
4pehl6 | why is it when you hear the same sound constantly for hours of the day, when you remove yourself from that environment you can still hear that sound? | I had a stocktake today and for 6 hours all I heard was beeping sounds of the scanners. Now I still hear them when I'm going to sleep. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4pehl6/eli5_why_is_it_when_you_hear_the_same_sound/ | {
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"Brains adapt in weird ways. Their entire goal is to find changes in the senses. \n\nThe brain deal with auditory change by filtering it out when it can predict it. After a while a sound that repeats becomes one big piece of background instead of a second of silence and then a beep. Your eye does this too when you look at something bright and then can see its imprint when you look away. Your muscles do it if you spend a day in the ocean and can feel the waves at night. What your hearing is the brain expecting the sound and filling it in. It's still adjusting for it, so you can still hear it. "
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3gb7cv | how does my gps request a signal from the gps constellation? is there a limit on how many devices can do so? | It's just amazing to me that GPS receivers (numbering in the billions maybe?) can all interface with the satellite constellation. How is this possible? Is it like a TV or radio intercepting an EM signal? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3gb7cv/eli5_how_does_my_gps_request_a_signal_from_the/ | {
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"text": [
"your GPS receiver doesn't interface with the GPS satellite. all it does is listen to the GPS satellite broadcast.\n\nbasically each GPS satellite is a radio station. there's no limit to how many people can listen to the same station. "
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|
1wg9ve | why does snow in southern state cause complete mayhem? | The explanation that they simply don't know how to drive in snow doesn't really seem enough in my mind. I mean, they still have dirt roads and surly they would be extremely cautious rarely having driving in snow before.
My best guess is that the vehicles simply aren't made to be driven in snow, but I really how no idea. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1wg9ve/eli5_why_does_snow_in_southern_state_cause/ | {
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"Snow and dirt are two different terrain.\n\nSnow leads to slippery roads that the usual southern driver is not used to handling that`s why we usually have snow tires specifically to handle driving in the snow better.\n\nDriving in the snow has its own nuances, and it`s a bit hard to explain to someone who has never driven in the snow.",
"The problem isn't just snow, it's ice. Driving on ice is very dangerous, and they don't have any sort of infrastructure to take care of it, like places where it's more common for it to snow. ",
"Warmer climates don't often have snow plows or salt, which is essential for clearing the roads. Schools and business often lack heaters, and drivers don't have snow tires. Lastly, the people are probably not used to snowy and icy driving. The roads are actually worse than they seem in warmer areas because it's slippery ice and slush."
]
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1iglmc | eli9: why can't a person/organisation/whatever display a picture of the prophet mohammed, but so many people in the world are named mohammed and there not be any backlash from the islamic community? | Were there people named "Mohammed" before he allegedly existed? Were there people named "Jesus" before him?
"" - the original spelling and/or pronunciation of these names before being translated. Not the names we use for them today.
Is that the reason why?
Did I just answer my own question??? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1iglmc/eli9_why_cant_a_personorganisationwhatever/ | {
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"It's not the word, it's the picture that they object to.",
"The Muslim prohibition is against images of Mohammed on the grounds that pictures or statues could be worshipped as idols. The idea is that Muslims should worship Allah, not a picture of a holy guy, and that having images of Muhammad could lead to practices bordering on idolatry.\n\nAs for naming a child, there isn't any rule that bans naming a child Mohammed, so it's considered acceptable, much like the Judeo-Christian tradition of naming children after people from the Bible. ",
"I was under the impression that images of people and animals in general aren't allowed and hardline muslims will follow that to the letter. Less fundamental muslims will care less about the whole rule but will still apply it to Mohammed.",
"To answer your secondary questions. \n\nPeople named Mohamed before? Possibly. \n\nPeople named Jesus before? Yes. Jesus is a Greek form of the name Yeshua, which itself is a form of Yehoshua or Joshua in English. ",
"In Islam you're not allowed to make images of the prophet Mohammed specifically because of the worry that could lead to people attempting to worship him as an idol. (Consider all the rather-inaccurate art of Jesus in churchs and you sort of begin to understand this.)\n\nIt's only the prophet Mohammed that's the problem, not the name Mohammed, or for that matter images of other people. (Technically you're really not supposed to make images of ANYONE but even zealots accept that non-Muslims don't follow this rule as long as the image is of anyone besides Mohammed the prophet.)"
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c0o78n | what the proposed extradition bill means for hong kong and mainland chinese citizens (please and thank you) | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/c0o78n/eli5_what_the_proposed_extradition_bill_means_for/ | {
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"China and Hong Kong is under a one country, two systems type of structure where Hong Kong could do it's own thing and China wouldnt interfere, which also included criminal prosecutions. Under this proposed bill criminals in Hong Kong can be extradited to China and prosecuted under Chinas laws, which effectively shatters the one country, two systems format. It means nothing for Chinese residents but have huge implications for Hong Kong residents as HKers are now potentially subject to the more restrictive Chinese laws and criminal proceedings."
]
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||
5ko9ju | why does soda "plop" out of the bottle when you pour it? | When you pour soda, it doesn't come out in one steady stream, it pours out in a string of plops.
This description isn't very good but I think you know what I mean. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5ko9ju/eli5_why_does_soda_plop_out_of_the_bottle_when/ | {
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"When the soda is pouring out the volume of space that plop used to be in needs to be replaced by an equally sized plop of air. When the soda is filling the entire opening of the bottle there is no place for the air to get in. Eventually the air gets tired of waiting for its turn and it forces its way in. The soda briefly stop, the air goes in, and then another plop of soda can come out. This process repeats until you lower the angle of your soda bottle so that soda can come out of the bottom half of the opening and air can go into the top half of the opening at the same time.",
"True ELI5:\n\nWhen soda comes out, air gotta get in.\n\nYou can even make an extra hole to stop the ploppin cuz air can get in.\n\n👍"
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8txcir | why is an action potential called an action potenial? | I understand what an action potential does, but I don't understand why it's called that. I really don't understand what potential means in biology i.e resting membrane potential, action potential, etc. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/8txcir/eli5_why_is_an_action_potential_called_an_action/ | {
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"This isn't really a biology question, more of a physics one. Although I'm not a physicist I can take a shot at answering this, but anyone studying electrostatics (although why would you willingly study this ;)) will be able to define an electric potential better than I can.\n\nA membrane potential is simply the existence of a difference in the electric potential on two sides of a membrane.\n\nWhat is an electric potential?\n\nAn electric potential is just a measurement of work. Specifically, the amount of work it takes to move a unit charge particle from an arbitrary location to a location within the electric field while keeping the unit charge at a constant velocity.\n\nSo, for example, the inside of a cell is negatively charged. Thus, any positive charge will be drawn into the negatively charged electric field, so a negative amount of force is required to keep the velocity constant. In this case, the electric potential is negative.\n\nThe outside of a cell is positively charged. Thus, any positive charge will be pushed away from the electric field, so a positive amount of force is required to keep the velocity constant. In this case, the electric potential is positive.\n\nThus, since there is a difference in the potentials on both sides of the cell membrane, we have a membrane potential.\n\nThe resting potential is the simply the membrane potential of the cell at rest. The action potential occurs whenever there is a quick change in the membrane potential."
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6a6965 | fcc comments. how many are needed and how do they make a difference in policy? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6a6965/eli5_fcc_comments_how_many_are_needed_and_how_do/ | {
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"The SOPA debate led to over 500k comments on the FCC. \n\nLess than a year later, the initial mainstream net neutrality debate that followed led to over 1M comments on the FCC.\n\nSo, to answer your question - historically it seems that you need roughly 500k comments to delay policy change for another year.\n\nThe question is, how many do you have to hit in order to actually cement net neutrality as policy. As that number is purely hypothetical, let's just say that as long as there's a monopoly on ISPs being privately opposed to publicly run, the answer is: infinite comments.",
"Let's say the a regulator wants to ban chemical X from a manufactured product. The regulator has a public comment period so that those who manufacture the product and use chemical X has an opportunity to provide feedback and ask questions about the proposed regulations. Maybe chemical X isn't has harmful as the regulators first thought, maybe the alternative is worst, maybe the costs would be so high to outweigh any potential benefits from banning it, or maybe there is a better way to solve the problem the regulator was trying to solve by banning chemical X. With the public comments, the regulator can then change the proposed regulations or prevent it entirely because now they better understand the impacts.\n\nFor the FCC and Net Neutrality, the hope is that the public comments will show overwhelming public disapproval so that the FCC keeps the current rules, rather than change them. Or, more likely, the hope is to get enough people in Congress to pass a law to overrule the proposed regulations."
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jm1vr | why do phones/mp3 players "lie" about battery percentage? | An example: My phone had a 100%-90% all day long after recharging and the next day it quickly went from 80% to 20%.
Another example: I played with my iPod until it showed me that it only has 20% battery left so I put it aside. a few minutes later it shows that it has over 40%. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/jm1vr/why_do_phonesmp3_players_lie_about_battery/ | {
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"text": [
"Because your phone/mp3 players is like a child eating a cake. Let's say that your parents need to leave to run an errand. They tell their friends, OK, I am almost out the door, my child just needs to finish eating the cake. The mom estimates that it will take about 5 minutes before he's done with the cake. Well, the child get's distracted with the balloons in the room and starts rubbing his fingers in the cake instead of eating it or starts throwing the cake on the floor. That's hard to predict. Maybe it will now take 10 minutes to finish the cake. If the kid just continued eating the cake, it would be done (the cake would be gone) and the original prediction of the mom would be correct. The cake is the battery and the mom is the operating system trying to estimate when the cake will be done. You are the baby that keeps doing different things with the cake. Doing different things with the cake causes it to last longer or shorter. Battery life is estimated based on how the device is being used. Or, how fast the baby is eating the cake.",
"It's actually not all that easy to tell remaining charge on a lithium-ion pack. Unlike other batteries, the voltage stays the same as the energy drops, so you can't quickly 'measure' charge like those old AA batteries where you pressed in the dots. \n\nThere are some ways to use the measurements to estimate state of charge, but they tend to screw up when current jumps up or down-- that's why your phone gets like two bars as soon as you plug it in, but it isn't really charged at all, it's just an error in the measurement.\n\n'Coulomb counting,' or keeping track of the power as it's drawn and just keeping a running tally of your energy, is pretty accurate as long as you are continually monitoring the rate of discharge. This is what notthatguyTHATguy is talking about, the rate of charge can change a lot depending on what you are doing with your phone, so you'd have to monitor it all the time to get an accurate reading. To continually monitor it is a lot of work; in the new electric vehicles, range/charge is really important, so they use a monitoring technique, but it's probably not worth it for your phone.\n\n\nAlso, batteries degrade/lose charge capacity over time. You've probably replaced laptop batteries before. There aren't definitive models for this aging, so it knocks some of the equations out of whack as well.",
"Because your phone/mp3 players is like a child eating a cake. Let's say that your parents need to leave to run an errand. They tell their friends, OK, I am almost out the door, my child just needs to finish eating the cake. The mom estimates that it will take about 5 minutes before he's done with the cake. Well, the child get's distracted with the balloons in the room and starts rubbing his fingers in the cake instead of eating it or starts throwing the cake on the floor. That's hard to predict. Maybe it will now take 10 minutes to finish the cake. If the kid just continued eating the cake, it would be done (the cake would be gone) and the original prediction of the mom would be correct. The cake is the battery and the mom is the operating system trying to estimate when the cake will be done. You are the baby that keeps doing different things with the cake. Doing different things with the cake causes it to last longer or shorter. Battery life is estimated based on how the device is being used. Or, how fast the baby is eating the cake.",
"It's actually not all that easy to tell remaining charge on a lithium-ion pack. Unlike other batteries, the voltage stays the same as the energy drops, so you can't quickly 'measure' charge like those old AA batteries where you pressed in the dots. \n\nThere are some ways to use the measurements to estimate state of charge, but they tend to screw up when current jumps up or down-- that's why your phone gets like two bars as soon as you plug it in, but it isn't really charged at all, it's just an error in the measurement.\n\n'Coulomb counting,' or keeping track of the power as it's drawn and just keeping a running tally of your energy, is pretty accurate as long as you are continually monitoring the rate of discharge. This is what notthatguyTHATguy is talking about, the rate of charge can change a lot depending on what you are doing with your phone, so you'd have to monitor it all the time to get an accurate reading. To continually monitor it is a lot of work; in the new electric vehicles, range/charge is really important, so they use a monitoring technique, but it's probably not worth it for your phone.\n\n\nAlso, batteries degrade/lose charge capacity over time. You've probably replaced laptop batteries before. There aren't definitive models for this aging, so it knocks some of the equations out of whack as well."
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31m5sa | i can't see air, yet i can feel it. when wind blows against my hand when i stick it out of a car window, what exactly is hitting my hand that makes me feel it? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/31m5sa/eli5_i_cant_see_air_yet_i_can_feel_it_when_wind/ | {
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"I believe you're feeling air pressure. When you stick your hand out the window of a car, the air passing by is momentarily blocked and compressed. I, unfortunately, don't know the details of the science.",
"What you're feeling is the collective pressure of trillions of air molecules hitting your hand with enough kinetic energy to move your arm. There are roughly 2.69 x 10^22 molecules per liter of air at sea level. \n\nWhen you blow up a balloon, it's the same thing: air molecules under pressure bounce around randomly, and trillions of them bounce against the walls of the balloon, keeping it inflated. \n\nThe word \"kinetic\" implies motion, inertia and impact. To say that air molecules have kinetic energy means they are literally like small particles flying around and hitting things. "
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||
7n0v8i | how does a finger print sensor work? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/7n0v8i/eli5_how_does_a_finger_print_sensor_work/ | {
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"When you take a close look at your fingers, you’ll notice that there are very small ridges on them. Everyone has a slight difference between the heights of these ridges, the distances between them, and all the empty spaces or unique points of these ridges.\nWhen you use a biometric system to record and use a fingerprint scanner, you often have two systems: an Optical and a Capacitor scanner.\nOptical scanners work by shining a bright LED light over the finger placed for scanning, and takes what is essentially a digital photograph of the finger print. The ridges closest to the scanner will reflect the most light, and the depths and curves will usually reflect less. The scanner records these “images” and sends the data to a computer that calculates the depths and distances between ridges, that are again, unique to (almost) everyone.\nThe second type of scanner, a capacitor scanner, is more commonly found in phones and various tablets, and is more commonly known. These work by using a capacitor that stores a current, and another computer that measures these currents. When you place your finger over a plate where the capacitor is working, the ridges closest to the plate will affect the conductivity of the capacitor, whereas the air in the ridges between will leave it relatively the same as before the finger was placed. A computer records these changes, and because each distance and curve between ridges are different, the recorded difference will be different. This is how your electrical “fingerprint” is recorded!\n\nEdit: I didn’t expect this to blow up so much! In regards to all the interesting questions, I will get to them as soon as I can, and read up on the topic to make sure I’m not spouting none sense. I’m currently slammed at work, but I will make time to answer you all. :)"
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||
2y6mas | why do windshield wipers push the water to the drivers side? | Many cars wipers take the water from the passenger side of the windshield and, push it to the drivers side, that can make it difficult for the driver to see. Wouldn't be safer to do it the other way around? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2y6mas/eli5_why_do_windshield_wipers_push_the_water_to/ | {
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"The wiper is vertical when it reaches the driver's side, getting more water off than the passenger side.",
"They do this so that the driver's side gets cleared better. It sounds weird, but it's true.\n\nThe wipers don't clear the whole windshield, just an arc across it. If you sit on the passenger side, water is pushed away from you, but the wipers only sweep across part of the windshield in front of you (one arc). Compare that to the driver's side, which gets wiped by both wipers. The overlapping arcs cover almost the entire driver's half of the windshield.\n\nThat's worth way more than avoiding the brief moment when the passenger wiper dumps water on the driver's side (which gets immediately wiped again as the driver's wiper returns to the start position."
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nfcgq | encapsulation in java | Basically the title. What is it, how is it used? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/nfcgq/eli5_encapsulation_in_java/ | {
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"Encapsulation is when you make some parts of your program unable to access other parts of your program. The purpose of encapsulation is to help you (or others) safely make changes to one part of your program without damaging other parts. Programs that use encapsulation are also easier to understand.\n\nIn Java, one of the main ways to use encapsulation is to create classes with private member variables.\n\nSuppose you want to make a class that represents a circle. Let's pretend that for some reason it's really important to you that the area of the circle does not need to be computed using pi*r^2 each time you want to find it. You might write the Circle class like this:\n\n public class Circle {\n public double radius;\n public double area;\n }\n\nAnd then when you want to create a circle you just call **new Circle()** and then set **circle.radius** to r and **circle.area** to pi*r^2.\n\nOne problem with this is that you are forcing anyone who uses the **Circle** class to understand the formula for finding the area of a circle. It would be better if only **Circle** needed to know how to find the area. So you might change your code to this:\n\n public class Circle {\n public double radius;\n public double area;\n\n public Circle(double radius) {\n this.radius = radius;\n this.area = computeArea(radius);\n }\n\n public double computeArea(double radius) {\n return Math.PI * radius * radius;\n }\n }\n\nNow you can create a circle without worrying how to find its area. But there is still a problem: what if you want to change the radius of the circle? When you change the radius, you also need to change the area. This is something that anyone who uses the **Circle** class needs to remember. It would be better if they didn't have to remember this.\n\nHere is how to fix this problem:\n\n public class Circle {\n private double radius;\n private double area;\n\n public Circle(double radius) {\n setRadius(radius);\n }\n\n public double getRadius() {\n return this.radius;\n }\n\n public void setRadius(double radius) {\n this.radius = radius;\n this.area = Math.PI * radius * radius;\n }\n\n public double getArea() {\n return this.area;\n }\n }\n\nNow whenever someone wants to change the radius of the circle they call **setRadius**, and the area is automatically updated to match the new radius. People using **Circle** don't need to understand how to find the area of a circle and don't need to worry about messing anything up if they set the radius.\n\nFinally, suppose you decide that you don't want to store the area of the circle inside **Circle** anymore, and you just want to compute it when someone asks for the area. Then you can change the class to this:\n\n public class Circle {\n private double radius;\n\n public Circle(double radius) {\n this.radius = radius;\n }\n\n public double getRadius() {\n return this.radius;\n }\n\n public void setRadius(double radius) {\n this.radius = radius;\n }\n\n public double getArea() {\n return Math.PI * radius * radius;\n }\n }\n\nEven though you've changed the way **Circle** works on the inside, anyone who looks at it from the outside sees the exact same thing. So if somebody has some code that uses **Circle**, you can make this change and their code will still work.\n\nI hope this helps!",
"Encapsulation is when you make some parts of your program unable to access other parts of your program. The purpose of encapsulation is to help you (or others) safely make changes to one part of your program without damaging other parts. Programs that use encapsulation are also easier to understand.\n\nIn Java, one of the main ways to use encapsulation is to create classes with private member variables.\n\nSuppose you want to make a class that represents a circle. Let's pretend that for some reason it's really important to you that the area of the circle does not need to be computed using pi*r^2 each time you want to find it. You might write the Circle class like this:\n\n public class Circle {\n public double radius;\n public double area;\n }\n\nAnd then when you want to create a circle you just call **new Circle()** and then set **circle.radius** to r and **circle.area** to pi*r^2.\n\nOne problem with this is that you are forcing anyone who uses the **Circle** class to understand the formula for finding the area of a circle. It would be better if only **Circle** needed to know how to find the area. So you might change your code to this:\n\n public class Circle {\n public double radius;\n public double area;\n\n public Circle(double radius) {\n this.radius = radius;\n this.area = computeArea(radius);\n }\n\n public double computeArea(double radius) {\n return Math.PI * radius * radius;\n }\n }\n\nNow you can create a circle without worrying how to find its area. But there is still a problem: what if you want to change the radius of the circle? When you change the radius, you also need to change the area. This is something that anyone who uses the **Circle** class needs to remember. It would be better if they didn't have to remember this.\n\nHere is how to fix this problem:\n\n public class Circle {\n private double radius;\n private double area;\n\n public Circle(double radius) {\n setRadius(radius);\n }\n\n public double getRadius() {\n return this.radius;\n }\n\n public void setRadius(double radius) {\n this.radius = radius;\n this.area = Math.PI * radius * radius;\n }\n\n public double getArea() {\n return this.area;\n }\n }\n\nNow whenever someone wants to change the radius of the circle they call **setRadius**, and the area is automatically updated to match the new radius. People using **Circle** don't need to understand how to find the area of a circle and don't need to worry about messing anything up if they set the radius.\n\nFinally, suppose you decide that you don't want to store the area of the circle inside **Circle** anymore, and you just want to compute it when someone asks for the area. Then you can change the class to this:\n\n public class Circle {\n private double radius;\n\n public Circle(double radius) {\n this.radius = radius;\n }\n\n public double getRadius() {\n return this.radius;\n }\n\n public void setRadius(double radius) {\n this.radius = radius;\n }\n\n public double getArea() {\n return Math.PI * radius * radius;\n }\n }\n\nEven though you've changed the way **Circle** works on the inside, anyone who looks at it from the outside sees the exact same thing. So if somebody has some code that uses **Circle**, you can make this change and their code will still work.\n\nI hope this helps!"
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5zuw8g | why is it there are no american made anime? (i.e. japanese style animation) | Aside from the obvious Avatar, I can't even think of another. I'm sure there are others. But certainly not as many as in Japan, or even a sliver of the amount. Why is this? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5zuw8g/eli5why_is_it_there_are_no_american_made_anime_ie/ | {
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"Well anime is a big part of Japanese culture. The American version of \"anime\" is cartoons I guess. Don't know why, but it's just culture. ",
"Avatar would be the closest, right?",
"Well, by definition it isn't anime unless it comes from Japan. The US has several shows that have anime elements in them(Avatar, some of the old Star Wars cartoons, various children's shows) but none of them are really anime. There is *one* American show(RWBY) that's considered anime by some people, but it's debatable and even so it's still somewhat different in style.",
"Because anime comes from Manga first(usually), and america does not have the same number of popular self published artist/writer.\n\nThe popularity of avatar shows there is definitely a market, but japan has a pre-filter on the quality level of what gets picked up by an animation studio in the first place. Writing off source material is called filler, so you might call most of american television programming filler.\n\nPerhaps more anecdotally, japans rail system allows for easy purchase and consumption of their weekly shounen jump series, while americans drive everywhere. If self driving cars become the future, and phones being in everyones hands, they have an opportunity to write stories to sell people. And with enough popularity, get picked up by ~~best corea~~ totally reputable animation studio inside america.",
"Umm... Robotech TV series anyone? - _URL_0_\n\nThis was a US based, US animated 3 part series based off of the Japanese shows started in 1985 that ran for 85 episodes.\n\nIt was fantastic, is 100% American made Anime, and predates Avatar by a long shot.\n\nThe Transformers animated TV show could also be considered American Anime. in fact, a lot of stuff came out in the 80s that might fall into that category, but nothing so firmly as Robotech.",
"Welcome to a classic question that has haunted the anime community for years, and continues to do so today.\n\nWhat is anime? How do we define anime? What distinguishes anime from a cartoon? \n\nEveryone's going to have their own answer to this question, and that effects the answer to yours. For example, one answer might be that anime is animation made in Japan for a Japanese audience. In which case, it's impossible for there to be an American made anime. If we start with the assumption that Avatar is anime, and that anime is a certain 'style', then how do we define that style so that it is simultaneously broad enough to include Kill la Kill, Cowboy Bebop, and K-On! while also being distinguishable from Bugs Bunny, the Secret of NIMH, and Beauty & the Beast?\n\nFundamentally, your question comes down to one of definitions. What makes anime anime? What is the distinguishing line between anime and American animation? What do we do with shows that fall somewhere in between? All of these lines are going to be subjective, and different for everyone. Knowing that, the answer to your question is going to differ.\n\nTo some interpretations, the idea of 'American made anime' is impossible by the definition. \nTo others, American anime could include shows like Samurai Jack, Panty & Stocking, and many others. \n\nUnfortunately, what this all means is that I don't think it's possible to give you an ELI5 answer to your question, since the question itself rests on a foundation that's nothing but individual subjective interpretations. ",
"US animation is heavily influenced by Disney. From the 20s to today Disney has been the world wide leader in all things animation. \n\nSo just like Japanese artists grow up influenced by their cultural world, so are US artists.\n\nOf course there's a market for anime in the US. There's 320 million Americans from all nationalities. There's a \"market\" for everything.\n\nBut few studios or investors will intentionally go after a market of 5 million when it can reach a market of 50 million. Sure, there will be pet projecat, and one-off successes. And that's awesome. But the anime market in the US is tiny compared to the market for Disney style animation.",
"There is. You've probably heard of it too. It's called Disney.\nEarly Japanese anime was heavily influenced by Disney, particularly the art style.\n"
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1vrcvf | how can verizon promise faster internet, by upgrading, when they can't deliver a fraction of the speed i'm already paying for? | I pay for 15D/5U, but have never seen more than 5D/5U. Does not matter what time of day, what day of the week, wired or wireless. How can they get away with under-delivering when they are positive that more speed is available to me (for an extra fee, of course)? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1vrcvf/eli5_how_can_verizon_promise_faster_internet_by/ | {
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"Because their advertising and your contract says \"up to\" X Mbps. As long as their network is configured to theoretically allow that amount, they're legally fulfilling their obligation.",
"how old is your modem? i use cable. but i upgraded my modem a while back and before that i had the same modem for close to 6 years or so. i noticed a HUGE improvement with the new modem. witch then led to me getting a new router as well. \n\nso it could be on your end your losing speed too. but then again its verizon. i would lookin to your equip. make sure it can take the speeds they are \"giving\" and if it can raise hell with the, maybe you have a bad line some where or something",
"FIOS? That shouldn't be happening. They probably configured something wrong during your install.\nCall them up, tell them your network is under-performing ALL the time. \nI have their 75/35 plan and get between 84 and 87 down, and 34 up. "
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2w4b4s | how does massive amounts of snow not cause flooding as it all melts? | As someone living in South Texas, Ive never experienced real snow. How does something like [This](_URL_1_) not cause massive flooding as the snow melts.
Edit: I say **real snow** because the only snow Ive ever seen was about a quarter inch of what looked like Dippin Dots [Pic](_URL_0_) | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2w4b4s/eli5_how_does_massive_amounts_of_snow_not_cause/ | {
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"It doesn't melt all at once and melted it's less water. ",
"1.) It melts slow enough that the drainage systems can handle it with ease.\n\n2.) Water expands when it freezes, and there is a lot of air in snow. So it is not as much frozen water as it might appear.",
"It does, it's just not flooding at the front door. The snow melts slowly in the spring as the temperature rises. Some years there is so much runoff that the Mississippi spills out of it's banks. Some times the Corp of Engineers [purposely floods communities](_URL_0_) to save others.",
"It sometimes does - acutely so if the snow is melted via additional precipitation like rain. However, often the effect is not accentuated too greatly primarily because snow doesn't all that often melt fast enough to cause any great concern. Certain confluences of factors such as rapid warming with rain can cause flooding if there is enough snow and additional rain. The other factor here too that helps mitigate this effect is that snow is just simply less dense than water so as it melts there is still a lot of air space occupying those huge mounds of snow",
"3 reasons. \n\n1: Ice expands as it freezes. \n\n2: Snow piled up is mostly air.\n\n3: Large amounts of snow almost never melt all at one time.\n\nAccording to the [NSSL (National Severe Storms Laboratory)](_URL_0_) 1 inch of rain is equivalent to 13 inches of snow, on average. So even if you have 6 feet of snow, that's only equivalent to around 6 inches of rain, which if it fell all at the same time, might cause *some* flooding, but snow rarely melts all in one day.",
"As a kid living near Lake Erie, a lot of creeks flood real bad. The creeks would start flowing and the lake would still be frozen. The (the authories, in this case) would bomb the mouth of the creek. Sometimes it helped , sometimes it made it worse. I know the Army Corps of Engineers has tried to fix Cattaragus creek for many years. The fire department has a special Firetruck boat combo for when it floods.",
"My area is pretty close to sea level, and at least once every spring we have a big rain while there's still snow on the ground and the ground is still frozen.\n\nOur storm drains back up, streets flood (mildly), the sidewalks are walled in by piles of packed icy snow so rain accumulates in the sidewalks, and the flooded sidewalks have a nice solid layer of slick ice under the water that's developed from months of people packing down snow by walking on it.\n\nIt's REALLY fun.\n\nBut then it all melts and we get on with our lives. Having quality reason boots with great traction helps.",
"Sublimation- a portion of the snow evaporates directly into the atmosphere. ",
"Remember also that 13\" of snow = 1\" of rain. So a 4\" rainfall is 4'4\" of snow. Now a 4\" rainfall will flood things like hell, but snow melts pretty slowly. So it's 4\" over 1-2 weeks, which is often not flood levels.\n\nAlso snow \"drifts\" against walls. It's probably 1' taller against the wall than the average snow level, higher if the windspeed is high."
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"http://imgur.com/wmfay5t"
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2eyoyk | how can gas station/mini-marts (in the us) reject large bills? | I understand that they often do not have the cash available to make change, but on the dollar bills it clearly states that it is legal for all debts, public and private. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2eyoyk/eli5_how_can_gas_stationminimarts_in_the_us/ | {
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"\"legal for all debts\" means *debts*. If they haven't agreed to the sale and you haven't received the goods, there's no debt yet.",
"From the [US Treasury on Legal Tender](_URL_0_):\n\n > ...\n\n > This statute means that all United States money as identified above are a valid and legal offer of payment for debts when tendered to a creditor. There is, however, no Federal statute mandating that a private business, a person or an organization must accept currency or coins as for payment for goods and/or services. Private businesses are free to develop their own policies on whether or not to accept cash unless there is a State law which says otherwise. For example, a bus line may prohibit payment of fares in pennies or dollar bills. In addition, movie theaters, convenience stores and gas stations may refuse to accept large denomination currency (usually notes above $20) as a matter of policy.\n\n > ...",
"A debt is when you owe somebody for goods or services that you have already received. When you set a candy bar on the counter, it isn't yours nor has a debt been created.\n\n",
"Just because something is legal tender doesn't mean they MUST accept it.\n\nIf I buy a $25,000 car and insist that I give them 2.5 million pennies, they certainly do not have to take it."
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x62ty | how natural immunity to diseases works | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/x62ty/eli5_how_natural_immunity_to_diseases_works/ | {
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"What do you want to know in particular? \n\nShort summary is that most foreign proteins illicit an immune response. Bacteria and viruses generally have several of these foreign proteins (called antigens). Your body has the ability to produce immune cells that respond specifically to any antigen. When a bacteria or virus multiplies in your body, its antigens will be all over your body. Certain immune cells capture these antigens and bring them to your lymph nodes, where the immune cell which reacts to the antigens present on the pathogen clones itself over and over until there are large numbers in your body. \n\nThese immune cells kill the pathogen in question, and once they are done some stick around. If that same antigen is detected in your body again, those immune cells that stuck around can multiply quickly to respond to the pathogen before it reaches the levels necessary to make you sick. "
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4jy79y | if you go at the speed of sound could you run on water? | To Reddit ELI5 Community
I thought of this randomly, but what would happen if you run on water at the speed of sound, would you run across, or just sink?
~GeneticTech | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4jy79y/eli5if_you_go_at_the_speed_of_sound_could_you_run/ | {
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"[Identity concealed] is not correct. You can run on water ([just watch this cute little lizard do it!](_URL_0_)), and you can do it at a speed significantly slower than the speed of sound. The exact speed required depends on the surface area and shape of your feet, the frequency and force of your steps, and the surface tension of the water. It's really an engineering question and not a physics question to optimize those parameters to run on water at a reasonable speed. ",
"You can \"run\" on water at much slower speeds than that. [For example if you are being pulled by a boat at a resonable speed you will be able to keep yourself on top of the water with just your feet](_URL_1_)\n\nIf you are moving at the speed of sound, the water would be pretty much as hard as concrete for you. So you wouldn't sink at least. But neither would you have any kind of control, the slightest bump would send you flying out of control. [The speed of sound if about 3 times faster than this](_URL_0_)",
"You don't even have to go that fast. Just freeway speed.\n\n_URL_0_\n\n > J.W. Glasheen and T.A. McMahon, two Harvard biologists who studied how the basilisk runs on water, found that in order to mimic the lizard, a human would need to run at almost 30 meters per second, \"a velocity beyond human ability.\" A man would also need \"an average power output almost 15 times greater than the maximum sustained power output for humans.\"\n\n30 m/s is about 70mph or 110kph. "
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72mfsu | what do engineers typically do all day when working for a company. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/72mfsu/eli5_what_do_engineers_typically_do_all_day_when/ | {
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"Look up detailed technical information and design solutions to little bits of a large, complicated problem.\n\nStudy customer requirements and think about how these might be solved.\n\nLook at problem reports (defects, bugs) and think about what must have gone wrong and how to improve the design.\n\n_URL_1_\n\n_URL_0_",
"You're going to have to be more specific than that. Train engineers run trains around, power utility engineers maintain and improve the electric grid, chip fabricator engineers work the chip production line in the fab plant, et cetera.",
"I visited a power plant once. There were E.E.'s giving us a tour. They had a lot of things to monitor. I am sure there were a lot of things the bosses could think up for them to do which did not include mowing the grass around the plant. But I had the feeling that as long as that plant was running smoothly those engineers were paid to be there. In other words, if something went wrong, the utility would need an E. E. with intimate knowledge of the power plant available. Knowing this, the utility was paying a few extra people to be there always because they would not be available on a moment's notice.\n\nOne thing that fascinated me was a little crank beside a generator. If things failed and that generator was not turning, there was small electric motor available too, but if there was no power, that generator would be cranked around and around. Allowing it to remain motionless would warp the shaft and render it useless. If there was a catastrophe that crank would be turned around and around saving the generator. If no one else was available, the E.E. would turn that crank to save a million dollar generator.",
"Civil engineers live in caves like mole men. You can tell us from other engineers by the dirty fingernails. "
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b3fr86 | how do we sleep comfortably during daylight but not when the lights are on at night? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/b3fr86/eli5_how_do_we_sleep_comfortably_during_daylight/ | {
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"Most likely has to do with the amount of blue light coming off interior lights. The sun is full spectrum and even has a warm yellow glow to it, which is relaxing. Blue light, is hard to focus on and causes eye strain and also is known to reduce melatonin production, which is a hormone produced for sleep."
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21j1ih | the differences between being pansexual, bisexual, and omnisexual? also, how do some people identify as neither male nor female, both, or something else entirely? | Thank you to everyone who gave me a genuine answer! | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/21j1ih/eli5_the_differences_between_being_pansexual/ | {
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"For some folks, labels like gay/straight or man/woman don't \"fit\" right. Some people prefer to skip labels altogether, while others might opt for a term like the ones you listed in your question. Let me try to break it down:\n\n**Pansexual/Omnisexual**: Some people will argue that there are slight differences between the two terms, but for the most part they are used interchangeably. The easiest way to summarize these labels is that these people focus on \"hearts, not parts\"- in other words, they are attracted to people of any gender/sexual orientation (we'll talk more about gender in a minute).\n\n**Bisexual**: This label refers to people who are attracted to both men and women.\n\n**Transgender**: People who identify as transgender do not identify with the sex they were assigned at birth (in other words, someone may have been born with a penis but identify as a woman or been born with a vagina but identify as a man). These folks may (but don't always!) choose to undergo hormone therapy, surgery, etc. in order to physically transition.\n\n**Intersex**: Usually, this refers to someone with sex characteristics that make them harder to categorize as \"male\" or \"female\" the way you probably think of those terms. There are a ton of different ways this can happen, but it's usually caused by some kind of chromosomal or developmental difference (for example, someone might be XXY instead of XX or XY). These folks may end up identifying as male or female or neither- totally depends on the individual.\n\n**Other gender stuff**: There are a ton of variations on gender/labels/how people choose to identify, but the bottom line here is that the gender binary (male/female) just doesn't describe everyone. People may not feel comfortable with choosing one of those labels- they may feel that they are a mix of both identities or that neither applies at all! As an example to drive the point home: Imagine someone identifies more with men and mostly has stereotypically \"masculine\" characteristics, but was born with a vagina and outwardly appears \"female.\" They don't like the label \"transgender\" because they don't plan to transition, and, really, they love their body exactly as it is. It feels weird to them when someone calls them a woman because for the most part they feel like one of the guys, but man isn't quite right either. Then what? They might choose to identify as both or neither, depending on the situation or even the day.\n\nAlso, for added clarity, [here's a neat diagram](_URL_0_) created by Sam Killermann. ",
"These terms, as stated in comments already made, can be confusing because they are used as personal identifiers as well as definitions of various forms of sexuality. This confusion can be understood by imagining two people who identify as Christians, for example. One person might try and live a good life by a set of moral codes, while the other attends church every Sunday and reads the bible in their spare time. Because these words are adapted by people, and used to self identify, their meanings can look differently depending on who's wearing them.\n\nBisexuality refers to a sexual preference for \"both men and women\". From an academic or critical perspective, this leaves out room for people who don't identify as somewhere inbetween, outside, or within both of these gender categories. Someone who is well read on gender and sexuality might use the term bisexual if they are attracted to both men and women, but not trans* individuals. In an everyday setting, like a high school, someone might identify as bisexual while being open to dating trans* identified people. The other terms are less well known, and therefor, less understood.\n\nPansexuality accounts for attraction/love/interest in people all across, or outside, the gender spectrum. In my exposure to the term, it is a way of indicating what some people might regard as \"bi-sexuality\" while respecting that some of the people they are attracted to don't fit in categories like man or woman. In some communities, pansexuality speaks specifically to the disregard of gender in selecting a romantic or sexual partner. The gender indicators of a person take no effect in one's selection of them as a viable partner. This, however, is not shared by all members of the pansexual community.\n\nOmnisexual is more recent a term than those above, and refers to different things by different people. For those who self identify as omnisexual, it often means an appreciation for the specific nuances of all gendered or non gendered bodies and people of the world. Rather than erasing the gendered components of a person when assessing their attraction, these parts of them are incorporated in what makes them desirable and attractive. There are pansexuals who identify with this line of thinking as well, I would even argue that the majority of those who identify as pansexuals and omnisexuals have more in common with one another than the terms lend one to imagine.\n\nAs for your second question, I want to point out the use of these words to mean different things, though are often conflated in everyday conversation.\n\nMale or female are words used to describe the biological sex category of a sexually producing organism. Cats, some plants, fish, and many other beings are categorized by these two words. A two-sex system or binary only accounts for bodies that completely adhere to the biomedical standards that were assigned to each sex. If a person is born with externally male genitals and ovaries, or has an XXY or non-binary chromosomal makeup, these categories don't serve them. In the global West, babies born with these bodies are often surgically intervened or socially raised to represent one gender or the other. The individual, however, might feel as though they are both male and female, or neither. \n\nConversations about men and women refer to gender, not sex. Gender is a social construct, that changes and holds different meanings throughout time and geography. A person is often called a \"boy\" and eventually a \"man\" if they are born and assessed as being of the male sex. Blue and pink blankets, long and short hair, and the many other ways we have to communicate about how we identify fall under gender, which doesn't refer to a person's biological sex.\n\nSo, if you are born into this world, and you are assessed to be a woman, you'll be raised under a set number of societally maintained standards. If you grow up, and realize that what everyone is calling a boy is more like you than what you see is a girl, then you might consider yourself \"trans\". This short prefix is used to indicate the wide range of sex and gender categories that aren't covered by \"man\" or \"woman\", \"male\" or \"female\". You could grow up as a boy, realize you don't feel much like a boy, but also don't feel like a girl. In this sense, you are neither of these categories. You might feel like there is another word to describe your identity in a way that the words you've been taught don't describe. Thus, people identify as \"something else entirely\", as you mentioned.\n\nI hope this was concise and clear, though I know it is super lengthy.\n\nSource: A Women and Gender Studies and Sexual Diversity Studies graduate. "
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5gjk5u | why are perfume commercials so goddamn weird?! | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5gjk5u/eli5_why_are_perfume_commercials_so_goddamn_weird/ | {
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"Perfume commercials - just like luxury car commercials, expensive watch commercials, and so on - are designed to sell the allure of stereotypical sophistication of wealth to consumers. \n\nIt's not supposed to make sense. It's a weird sort of thing along the lines of Hans Christian Anderson's \"The Emperor's New Clothes\" fairy tale.",
"Because you can't transmit smell over TV, and perfume doesn't really smell like much other than perfume.\n\nIf I show bacon sizzling in a pan on TV, your might not be able to smell or taste it, but you can imagine it pretty easily. But if I show you a bottle of perfume, you have no idea, and most people who aren't super serious about fragrance don't have the vocabulary or experience to understand a description like \"notes of orange, gunflint, flint, vetiver and benzoin.\"\n\nSo advertisers are kind of handicap when it comes to describing their product, so they have to get creative.\n\n",
"All they can advertise on TV is the name. You can't smell it on TV. It isn't supposed to be seen when used. \n\nSo, they have to get the audience to know their name, and the shape of their bottle somehow. That somehow is by recruiting a famous name/face and being \"so goddamn weird\"",
"Savage, I'm Johnny Depp, I'm going to dig a home in the desert and put this necklace in it then place a rock on top to mark it. ",
"Those commercials seem to still work though. As proven by this discussion, the commercials were remembered and made an impact",
"What matters for perfumes is that you remember it or atleast it left an impression on you. Be it on video or in person.",
"A few reasons, one they're selling a smell, something that doesn't translate well over tv, print or radio. Second it's a smell, you either like it or you don't. \n\nSo what they're selling is an image of a lifestyle. For example Axe products are mostly marketed to young men, who [buy their own products](_URL_0_). So axe commercials are, [wear this](_URL_4_), get lots of hot chicks fawning over you. Because that's what a young man (generally)wishes for. \n\nColognes that are marketed to older men, like [Polo](_URL_2_) are mostly purchased by women. So the guy is always some suave fit guy who lives an active lifestyle, does cool things, and always loves the his woman. If you are male, what appeals to you in this [commercial](_URL_1_)? Probably almost nothing, you probably have very little interest in seeing a shirtless, fit, good looking guy. This commercial has a lot more interest to women, sophisticated well dressed guy, who looks even better at home. \n\nWomen's perfumes pretty much all sell the same fantasy. Wear this, and you'll have the perfect date with the perfect guy.\n\n_URL_3_\n\n_URL_5_ Same thing, eyes met in a crowd, given a flower by a cute kid who did something innocent yet romantic. ",
"I think there are two main reasons. 1. They are selling a product which is supposed to stimulate your senses and emotions so the commercial has to be a bit mystical. 2. Somebody in the past made a commercial in this style and since then everybody is making it the same way and nowadays they just have to continue it because that is what customers expect the commercials to look like.",
"To make you remember them. Whether you're annoyed or astonished or whatever by them, the point is to get a brand name in your head and it works. ",
"I say the same thing about Drug commercials. Everyone is so unrealistically happy. Especially that one about the skin psoriasis drug with the chick putting a dress on and acting all embarrassed and then comes out twirling around in the dress. That commercial makes me roll my eyes.",
"People have addressed commercials that appeal to demographics, like axe or what not, but don't seem to have touched on the real weird stuff you're asking about.\n\nThese ones seem to me to exploit the same things that artists and musicians often do.\n\nWith clever word selection, combined with certain images and sounds, you can give someone a really strong impression and make it stick with them.\n\nThis seems to rely on a few things. \n\nThe first is things that have very broad associations, things that imply space, grand scenes, atmospheres, etc. The second is associating these with physical sensations and body stuff. The third is making it contradictory to some degree. Basically you want to string together words in a way that imply an enormous amount of other things, associate them with the body and sensations, and give the impression that they somehow fit together when they really don't. Then of course associate that with your product or brand. Stuff like this seems to get stuck in the brain way better than other things. I speculate the brain is constantly trying to reconcile it's model of the world with it's model of the body, so introducing very vague and broad things that touch on both make it get stuck churning over the nonsense data, which makes the product more memorable.\n\nFor example, take this lyric from Far From Any Road by The Handsome Family:\n\nFrom the dusty mesa\nA looming shadow grows\nHidden in the branches\nOf a poison creosote\nShe twines her spines so slowly\nTowards the boiling sun\nAnd when I touched her skin\nMy fingers ran with blood\n\nTo me this song is very haunting, with the music and so forth of course. It implies broad open spaces, it's ominous, it implies both the beauty and violence of nature, it touches on sex/gender on a primal level, it's very textual with body and touch references. It implies some kind of broad unity and mystery of things, but you don't really know exactly what it's getting at, it's an impression that's difficult to articulate or categorise.\n\nDunno if any of that helped or made sense but there you go.\n",
"These ads are using an audio-visual medium to advertise a product that is based on neither sight nor sound.\n\nCreative liberties in the interpretation of said product were taken.",
"This post made me think of an ad I stumbled on the other day & thought what the hell are they selling? \n\n[Flowers...no - wedding venue?...nope. Wedding dress...fuck...chopper ride? Godammit fucking perfume.](_URL_0_)",
"My family and I have a running joke about perfume adverts, as they're always so weird. It started off as, when watching television, if an advert was random or just some stick thin woman flouncing around, throwing adjectives about, we'd call out the perfume advert. Soon enough it has transferred over into everyday life, if something weird is happening or we see something strange, someone is probably filming a perfume advert. Lady on the train talking to herself? Perfume advert. Ice cream man's truck broke down and now he's giving out free ice cream whilst blaring Metallica? Perfume advert. Caught Uncle Steve wearing women's clothing and crying? Perfume advert. ",
"I know [the commercials](_URL_0_). In short, they try to give some weird sense of dropping a European film noir stunt schwanz in her pants. Eurosex sells, or so they figure. As they keep making them. ",
"My favorite. Featuring the very talented Margaret Qualley. _URL_0_",
"One odd note, it's likely scent is objectively the hardest sense to even speak about in any clear way. The words for it, like adjectives, just don't even exist. Not general ones, anyway.\n\nThere are some reasons for this (vision comes down to a few basic, common elements, so does taste, so does touch, so does hearing, but scent doesn't seem to) but the point is... there's not really a good way to simply, frankly talk about a scent, other than tautologies. (i.e. the lavender-scent smells lavendery)\n\nOnce direct description is ruled out, you quickly shift to metaphor (\"the lavender-scent smells like a calm summer day\") and before long you get to the kind of commercial you're talking about.",
"I'd be curious about pre-Calvin Klein [starting with Obsession ads in the early-mid 80's] tv advertisements and how weird or not they were. The Calvin Klein perfume ads were... well, I could youtube up some links, I don't know if they stayed in the zeitgeist or got lost along the way. Y'all kids know what I'm talking about here? Anyways, if you don't, they were striking and wierd and... jejune. _URL_1_ cf. _URL_2_\n\n [David Lynch directed a couple, featuring Benecio del Toro and Heather Graham, both lookin all young and good-smelling and sexy and shit] _URL_0_\n\nAnyways, I don't know if those ads moved a lot of perfume or built the brand or just were commercials that people remarked on and ignored the product being hawked, but I'd wager without looking into it that perfume ads after that being cryptic and arty or oblique are following that ad campaign's aesthetic ",
"They are selling something that, if they described it to you, would not be all that interesting and probably would mean nothing to you. \"It has a little lemon in it, and something that smells vaguely of cat piss but we swear is *not* cat piss, and the following thirteen chemical compounds that have tested well in clinical trials involving impoverished Chinese men paid to sniff impoverished Chinese women all day...\" \n\nSo instead:\n\n1. They sell by image association: the spoken or unspoken promise is that this expensive little bottle of stink will make you sexy or mysterious or dangerous or independent or kinky or strong or healthy or whatever, or at least persuade others (rightly or otherwise) that these attributes apply to you, because they have just shown you sexy or mysterious or dangerous or independent or kinky or strong or healthy images while reinforcing the perfume branding in your mind. \n\n2. They sell by name recognition: when you stare at 300 bottles of perfume on the counter this Christmas season and wonder which one to buy yourself or your SO or whoever, they want very desperately for you to recognize their product's name out of the 300 and associate it consciously or subconsciously with positive things. The ads are intended to train you to automatically feel excited one way or another by the name and bottle and associated ad stuff.",
"Should recommended a parody made by a Brazilian youtuber about this. \n_URL_0_",
"English comedian Lee Mack did a great skit on that particular subject.\n\nHere you go, enjoy:\n\n_URL_0_",
"Like this?\n\n_URL_0_",
"_URL_0_. I know people dont watch youtube videos in the comments but this goes along with this subject so well that your just letting yourself down if you dont watch it. ",
"The plot is to depict an experience. Perfume companies' advertisements sell lifestyles. The companies aim to shape consumer behavior in a certain way. Most perfume advertisements use the plot to associate people to a certain behavior, a certain experience (rebellious, romantic, etc...)\n\nThe advertisements that aim for the younger crowd tend to associate their perfume with a rebellious tendency, or sweet tendency, or whatever the companies find out about the younger population. Those that aim to reach the older population tend to have sexually implications in the plot. \n\nThe slogan is to promote brand recognition. So when you think of perfume in general, you recall that brand before any other brand names. ",
"They're attempt to sell an essence or an atmosphere. And hoping that your imagination will be able to fill in the blanks where there's ambiguity.",
"[The greatest of all time](_URL_1_)\n\n[Runner up](_URL_0_)",
"It's an attempt at profundity within the half minute or so the ad gets, because it's trying to sell a lifestyle, and appear something greater than ultimately a bottle of smelly oil/water.\n\nThe lower tier stuff will still broadly make sense, but the higher up the expense scale goes, the more you enter the heady heights of the well-heeled fashionable trend-setting world.\nWhere people wear funny clothes, everyone looks perfect, and everyone's thoughts are (at least superficially) deemed some interesting deep delve into philosophy.\n\nAnd you to can be part of that world, for the small, small investment of the fat price-tag for an expensive, brand perfume.\n\nPlus the ad is more memorable if it leaves you going \"*dafuq?*\"\n",
"Because they're selling a concept. They're trying to create an impression, play on your emotions. They can't say \"Well, it's kinda citrusy with hints of vétiver.\" ",
"Some products are sold by product attributes and some are by emotional ones. Used to be that more and more products were sold by physical product attributes. Levi's used to be marketed as \"stronger denim, better stitching, rivets by pockets, for example. And these were actual claims that separated them from the competition. But as technology and production methods advanced there was less and less differences between various brands. Any two jeans were comparable in terms of product attributes so brands started focus on building a brand and separating themselves from the competition by style and emotional attributes. One brand claimed the rebellious cool youth, one brand claimed the rough cowboy look, etc. They were focusing on associating themselves with a certain lifestyle, a certain look & feel. Perfume ads are doing this very thing and they're also including the visual language of high end products which also generally tend to focus mostly on emotional attributes and attempt to evoke feelings, distinction, and an identity. We can expect to see more and more products being advertised in a similar fashion.",
"I honestly really enjoy watching perfume commercials. They are very artsy, look nice and sometimes even have good music.",
"You say what a weird fucking commercial but you remember it. Then when you go out to buy some you're like oh that's that perfume that had the really weird commercial. And you wonder what does it smell like?\n\nSo yeah they want you to remember it and maybe when you go buy some you will smell it and like it.",
"Well think about it. You got a product that sells based on smell, advertising on a medium that can't portray that. So you gotta be weird af so that as a consumer, you remember the name at least. I think this attempts to avoid vampire creativity. ",
"Can anyone give us a happy kanye for once?",
"A side question: what were perfume commercials like in the 1950s and 1960s, when most commercials (in the US, at least) were 60-second long-copy narratives by nasal-inflected men? \n\n\"Saaaaay, ladies, is that cheap drugstore store scent letting you down? (♪ wah wah trumpet ♪) (♪ cheesy production music ♪) Go to your nearest fine department store, and demand genuine Chanel #5! Chanel #5, accept no substitutes. A deluxe French scent that smells traditional, but with a drop (♪ ding! ♪) of space-age Aromolon from Dow Chemical! Aromolon, the miracle of modern chemistry that lets you keep that classy Parisian aura all day! Ladies, ask your husband to drive you to the nearest fine department store now, and buy Chanel #5! Ask for it by name! Genuine Chanel #5, now with space-age Aromolon! For a limited time, buy a three ounce bottle of Chanel #5, and get a free chrome-plated cigarette case! (♪ dreamy piano ♪)\"",
"Based on Johnny Depp's recent cologne commercial, if I wear it, I'll travel deep into the desert and bury any sentimental or meaningful trinkets that I typically wear. ",
"It's more than turning a metaphor for odor into tv. There's thought behind it. \n\nSmell is strongly linked to memory. A smell of cooking, or maybe nature can transport you to a time and place in your life. \n\nThe sum of memories is your identity. Your first kiss while camping among the pine trees. That first big night out in the city after a promotion. The floral arrangements of lavender at your wedding. \n\nThis makes up who you are through smell. \n\nPerfumes and colognes aren't just a pile of odors mixed up to get you laid. They try to represent a personality during a time of year. Is the smell light and flowery? Maybe something great for a spring afternoon. Sharp, intense that feels modern? Perhaps that's what you wear to the meeting today. \n\nThe smell becomes you. And to other people you are that smell. And anytime they smell that odor range. They remember *you*. \n\nPerfume and cologne commercials are some of our best attempts to express what creates a memory or what creates an identity in motion. All so you the consumer can help guess when and where that odor would be used, and if it's the right kind of smell you want to embrace and project. \n\nAnd besides. All the weird music video directors need to get paid in the off season. Its a specific kind of director that only works in expressionism...so on the pragmatic side a limited talent pool also narrows how all the commercials look. ",
"Is this from that other r/askreddit thread?",
"This Brazilian guy did a satirical commercial throwing random images and words.\n\n_URL_0_",
"I was watching TV before work today and a commercial came on , I could not tell if it was a trailer for Ghost in the Shell, or a perfume commercial - ended up being perfume. ",
"A while back, I talked about the perfume business with a product manager who actually worked for a well known company normally famous for soap, toothpaste and nappies. Of course, the brand has some designer name on it, and an exotic European brand as \"Cincinnati\" doesn't really stir up enthusiasm.\n\n\"The product is just alcohol with some trace additives\", he claimed, he went on \"Sure those additives are expensive but they go a long way, the Nose (perfumer) costs a bit, but that is it. Once the blend is done, it is all about selling a dream so the packaging and marketing must tie in. The customer must associate the smell with the imagery... A beautiful young lady dancing through a classical European city. The person wearing the perfume must identify with the model in that setting.\"\n\n",
"Let me be pretentious for a minute. One thing you have to bear in mind is that perfumery is an art form, and a lot of perfumers will sit down with the aim of not only making something that smells nice, but with the goals of any other artist in any other medium - expressing themselves, evoking an emotion or an experience. For example, I defy anybody to smell L'Air du desert marocain and not immediately have an image blow up in their head of those huge National Geographic spreads of the desert at night. \n\nA fragrance might have a more concrete idea like \"tropical flowers, in abundance\" or \"figs with milk\"; or it might be something totally abstract, like Après l'Ondée which is called \"after the rain shower\" and smells pallid and sad and like a rainy morning, as described. Still, even without high aspirations (sometimes people will just sit down and go \"I want to do something cool with this almondy aroma chemical I like\" or \"okay, let's do a rose soliflore, but a modern one that won't make our target audience think of Grandma\") I think most fragrances have a mood, the same as the most basic still life or landscape. \"Figs with milk\" could evoke comfort and health and sort of that New Age spa kind of vibe, or you could want to drown the wearer in honey and incense to accent the fig and make them feel like they're dying of decadence on a Mediterranean villa somewhere. Or you could make an astringent, bracing men's fragrance that accentuates the notes in a fig that come from a real plant, a fragrance that reminds people of the sap and leaves of the tree, like taking a walk among wild figs in nature ... you know, you can do a lot here. This is often how perfumers like Jean-Claude Ellena or whoever will approach their work.\n\nThis is the most representational that fragrances can get and I'm using that idea to illustrate a point, but for instance I smelled something called Safran Troublant once that paired saffron and vanilla and the smell was so weightless and so smooth that I couldn't smell it without thinking of a gliding motion ... you see, it has a mood, a feel. How you could represent that in a commercial? I don't know - figure skaters, ribbons of silk. You'd get close, at least. If you showed images of people climbing a mountain in a storm that would have nothing to do with what you got out of the fragrance at all.\n\nSo, you have the mood of the fragrance, or the mood they're aiming for, anyway. I wouldn't really take the fruity floral kind of fragrance (imagine that sugary crap put out by Justin Bieber and Lady Gaga's brands, for instance - that mood is just \"sexy, approachable, girlish, fun\" and not anything too complex, but it has a mood nonetheless) and advertise it with a lot of sturm und drang, same as a museum curator wouldn't put Van Gogh's sunflowers in a room full of paintings of Christ being tortured. It's just not what the fragrance is like.\n\nYou could say - well, a fragrance is just something that smells decent. Sure. And Monet's Woman with a Parasol is just a chick with an umbrella. Can you imagine Axe on a sixty-five-year-old professor of literature? The mood is wrong.\n\n(Honestly, the more realistic answer is that a precedence was set a few decades ago with Calvin Klein's ads and now people in advertising feel like they can have fun and do something weird. But fragrance, being the most abstract form of art, is naturally going to lend itself to this.)",
"Because you have to sell a product based on smell using images and sound. Pretty much the only thing you can do is create a memorable image or sound to resonate in people's minds so they'll remember the perfume when they see it in stores.",
"Ha. I write commercials for a living so maybe I can give you some insight. (Agency side representing many different companies.) \n\nFirst of all, throw all logic out the window. Don't try to build a foundation of reason and assume marketers do the smartest most logical thing to maximize their profits. They'd like to think so, but no. This is too subjective. Often the personality of the marketers making decisions plays a larger role than data or who they're marketing to. \n\nEach product category like automotive, fast-food \"Quick Service Restaurants,\" fashion, etc has a particular culture that's been built up over the years. There's an expectation of what an ad should be and they all (generally) try to mirror each other with small differences. Occasionally, someone has the guts to try something really different but most people generally just want to keep their jobs and feed their kids. \n\nThis is why each car company does ads where they just rattle off car features in voiceover but also do \"brand\" ads that mix things up. Shoes used to be about technology until Nike set a convention that it's more about athleticism. Think about how every jewelry commercial is the same. \n\nSo with fashion/perfumes they need convey a sense of luxury and upscale-ness. Somewhere down the line, someone decided that a cryptic, artistic approach would be appropriate and it must have worked well enough. Their boss liked it. It set a convention and was duplicated. It evolved over the years into what you see today. \n\nThat's why these damn perfume ads don't make sense across many different brands at many different companies. \n\n",
"Advertising signs they con you\nInto thinking you're the one\nThat can do what's never been done \nThat can win what's never been won\nMeantime, life outside goes on \nAll around you\n\nBob Dylan ",
"And then there's THIS ad, which bucks the trend \n\n_URL_0_"
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"https://www.youtube.com/watch?v=n0wLsmwiIRQ",
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605c6n | why do people tend to snap their fingers when trying to recall something? | Does it have to do with the sound or rhythm of the snapping that helps us remember things? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/605c6n/eli5_why_do_people_tend_to_snap_their_fingers/ | {
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"nothing to do with anything. it's learned behavior. it is only done by people who have been exposed to other people doing it. stop next time you're doing it and ask yourself why. you'll have your answer. you're doing it so the person you're snapping at shuts up and lets you think and doesn't interrupt you. its your local way of communicating that you don't want to be interrupted verbally. you're \"thinking aloud\" and don't want their input so you're showing you're not listening by generating noise that you control, and can ignore as you think, but which they feel obliged to accept means 'shut up' because it interrupts them if they try to contribute. "
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358nqs | why does cartoon network (and to some extent other networks) have its logo onscreen constantly? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/358nqs/eli5_why_does_cartoon_network_and_to_some_extent/ | {
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"text": [
"It is to identify the source if it is played at some other time. For people watching it it is just an ad but for, say, a theater showing it it is evidence that they aren't necessarily using a legal source."
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||
3ak26l | why do well-fed pets still scarf down their food in one big bite? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3ak26l/eli5_why_do_wellfed_pets_still_scarf_down_their/ | {
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"Same reason people overeat.\n\nWe are genetically programmed to act as though food is scarce. We eat as much as we can as fast as we can, so we have the calories to go without for a few days. Our bodies don't know food is so abundant that is no longer necessary."
]
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387db9 | why does the troposphere move faster than earth? | It takes the troposphere 2-3 weeks to move eastwards once around the globe.
It takes the globe 1 day to rotate around its own axis, so when earth has spun 14 (21) times, the troposphere has spun 15 (22) times - making it at least 5% faster.
What am I missing? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/387db9/eli5_why_does_the_troposphere_move_faster_than/ | {
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"The atmosphere does not rotate faster than the earth. You appear to be looking at a small segment of the atmosphere: the prevailing westerlies in the lower troposphere in the temperate regions of the planet and attributing that motion to the whole atmosphere. The temperate prevailing westerlies are only one component of the worldwide circulation of air, which also has easterly, northerly, and southerly components, and is quite complex. "
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48vdic | what is actually happening when you "charge" something that is glow in the dark? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/48vdic/eli5_what_is_actually_happening_when_you_charge/ | {
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"The chemical bonds in the glowing component can temporarily store energy and then release it at a constant rate. When \"charging\" it, you're exposing the chemical to ultra violet light (or any wavelength of light i guess it depends), the photons excite the molecules and energy is stored. The energy is then released as the molecules go back to their typical energy state. This released energy takes the form of light.",
"There are certain substances that are [Photoluminescent](_URL_0_) meaning they absorb photons readily, but they emit them much more slowly. That's why if it's inside your house, it will be dull. Take it outside or hold it up to bright light, then put it somewhere dark and there's the glow in the dark.",
"Another question: why do glow in the dark objects lose their ability to retain glow over time? ",
"The electrons in the molecules move up a level and become excited while absorbing photos from the light source. Then when the source goes away the electrons move to a lower energy level and this causes photons to be released.",
"Quick version: this is for glow-in-the-dark things that you charge by light, so no chemical reactions.\n\nIn one sentence: Light hits the object, and its energy is stored in the electrons.\n\nAll material has protons and electrons. The electrons exist in energy states, akin to stair steps. Electrons can absorb light (in the form of a photon) and jump up from their ground state (lowest energy) into a higher, or excited state. This is like jumping from the bottom to a first or second step. (because you jump when you're excited, right?) To get rid of that energy, the electron can emit a photon of light.\n\nLike stairs, you can only jump to an step. You can't jump half a step up and stay there.\n\nFluorescence, things that light up under a blacklight, this happens fast so that when you turn off the blacklight (the exciting light) light the glow stops immediately. But the light coming out of the blacklight isn't the same \"color\" as the glowing things. That's because the electrons don't jump down the same energy level. They hop down to an step in between before dropping down to ground. Like if you were able to go up to the 5th step but want to jump down two steps and then three.\n\nGlow-in-the-dark things are phosphorescent. Phosphorescence is different from fluorescence. It's like instead of jumping straight down, you hop on the banister, and hang on there for a little while before jumping down to the ground. That's why the glow-in-the-dark material still emits light after you remove the light to charge it.\n\nSome things left out: that light energy is related to wavelength, that electron levels have vibrational levels too, non-emissive relaxation."
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67a41w | how does organ compatibility work? | I'm curious as to how organ compatibility works, and why? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/67a41w/eli5how_does_organ_compatibility_work/ | {
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"Multiple factors go into testing if someone is compatible for receiving an organ. The two major tests that must be done are testing for Rh/blood type and Major Histocompatibility complex (MHC). Think of MHC's as a flag that cells show to the body. If this \"flag\" does not match with the recipients then the immune system with reject and attack the transplanted organ. Only identical twins with have identical MHC's so the doctor must try to match them as close as possible. In almost all transplants the recipient must take immuno represent drugs so the body will not reject the organ. \n\nIn regards to blood type and Rh factor the recipient an donor must match. There are 4 different types of blood A, B, AB, and O. AB is known as the universal acceptor and O is known as the universal donor. People with type A blood have antibodies that are specific for this type of blood and can not receive blood with type B antibodies. Type AB blood have both antibodies so they can receive any type of blood. Type O blood have no antibodies so they can donate to anyone however they can only receive type O blood. Blood also has a Rh factor which is a protein on the blood. Someone with a negative Rh factor will not be able to accept Rh Positive blood due to the immune system thinking this protein does not belong. Someone with Rh positive blood will be able to receive whatever blood they want due to the that protein not being there for the immune system to attack."
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2a2ez1 | if the us is allied with saudi arabia, why did we topple saddam hussein and replace him with a cia trained shia who is allied with iran? | Why did we install Maliki? Seems like he is obviously not aligned with American interests. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2a2ez1/eli5if_the_us_is_allied_with_saudi_arabia_why_did/ | {
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"For better or for worse the Americans did in fact install a democratic government. As a result, the Americans could not just \"install\" their preferred candidate for PM.\n\nAfter the civil war, the Americans decided the Iraqi political system needed change. Maliki, since returning to Iraq, had impressed the right people working for the Americans, was not corrupt, and was politically weak which would necessitate building a coalition among the differing factions. The Americans, despite reservations, ultimately decided to back Maliki for PM because he would be able to win support from the Sunni, Shia, and the Kurds. \n\n"
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d8daam | how is interplanetary internet ever going to be possible, even if it does, what could be the possible bandwidth someone would get? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/d8daam/eli5_how_is_interplanetary_internet_ever_going_to/ | {
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"Bandwidth isn't the issue, it's latency. A nice laser or microwave beam could carry a lot of information at a very high bandwidth, but the minimum speed-of-light round trip time Earth to Pluto is 10 hours.",
"There is actually people working at this. Currently the internet standard RFC5050 have multiple implementations and is running on ISS as well as on other probes and satellites. However it is currently being replaced by newer variants. The problem with interplanetary internet is that there is plenty of bandwidth but information only travels at the speed of light so it still takes quite a while for information to arrive. In addition there is issues with planets eclipsing the satellites so communication is disrupted at times. The current Internet protocols is based on the idea that you can establish a continuous communications link between the two parties. So establishing communications takes several round trips of packets before the first data is sent. And if one link in the chain is broken then communication is not possible. So what they do is to send huge bundles of data instead of individual data packets. Each node in the network will take responsibility to deliver the bundles it have received even if it have to store it for a few hours to wait for an eclipse to end or if it finds out it is better to route it a different direction. There is however still a lot of unsolved problems. For example encryption and authentication is not yet quite solved but there are a few ideas and standards out there. There is also a lack of implementations and testing in general. So help would be beneficial."
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6gg94z | why do cops pull you over then ask you if you know why they pulled you over? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6gg94z/eli5_why_do_cops_pull_you_over_then_ask_you_if/ | {
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"It's so you can't then challenge the ticket. If the cop pulls you over, asks you that, and you say \"I was speeding,\" then you can't challenge it later. ",
"Because it puts you on the spot. \n\nWhen you get pulled over, most people hope to get off with just a warning, and part of that is being polite and respectful. Lying is impolite, and will likely get you a ticket, but leave open the option of contesting it in court. Telling the truth (assuming you were speeding or something) is a confession, the officer might respect your honesty and give you a warning, but if they don't, it will be more difficult to contest the ticket.\n\nAlso, like any open-ended question, it helps gauge your level of nervousness and/or intoxication, to help the officer determine if you are breaking any other laws.",
"\n\n\nCop here. From the UK, so I've already seen your comments about being scared of men with guns, I don't have one. \n\nThe answer is different reasons. \n\nI'm not a traffic cop. I don't even carry a ticket book, so if I do stop someone, pretty much 99 percent of the time, it's going to be advice and a warning only. \n\nI therefore ask that question as it gives me an insight into what sort of person in dealing with. \n\n\"I'm really sorry Officer, I was speeding because...\" they are admitting their fault, apologising, being polite - no need to spend to much time here as they know exactly what they've done, a quick warning and they are off. \n\n\"I don't know.\" If it's clear they WILL know, I now know I'm dealing with someone whose willing to lie to me. It's not going to change the outcome, it'll still be a warning, but this time I'm on my guard a little more and on the lookout in case they are hiding something else - probably more likely to run a few checks on them before they go in case there are other issues. \n\n* * * * *\n\nHowever... Traffic Officers may well be asking that question, fully intending to give you a ticket, hoping for the admission as then it's less likely you will contend the ticket! \n\nThere's no \"right\" answer. However, for me (and remember I'm in the UK, I'm not sure how different it is in the US) if I am stopped whilst driving (I have been twice since being in the job) , I'll always admit to what I've done, purely because I know that if the traffic officer wants to give a ticket, they already have the evidence to - if I say \"I don't know\" it doesn't actually help me in the slightest.\n\nUnfortunately, as the member of public you can never really know the right way to play it without knowing what the cops intention is as he's walking over to your car. Politeness regardless of the choice never, ever hurts though! ",
"Haven't seen the \"correct answer\" here so I'll give another reason. I've been taught that it's to show/gain control. When you're the one asking the questions, you're the person of power in the first place. I always ask a question in return to level the field and also keep from admitting guilt. \n\n*\"Do you know why I stopped you tonight sir?\"*\n\n\"I'm not sure what I'm being stopped for to be honest. Why are you stopping me?\"\n\nPolice don't even all use it anymore, usually they do ask a question to gain control but most have a preferred structure of conversation with you and try to be more polite. Probably more of a movie trope than anything. Any cop I've ever talked to have asked how my night was going as a courtesy and then told me exactly what they thought was up, obviously different per case. It's pretty hard to deny an outright question and a lot harder to dodge than an open ended question like \"do you know why I stopped you?\"",
"I got this from a cop: It is a way for the driver to self incriminate, by saying something about your speeding? or any other infraction.\n\nThe best answer is I don't know, followed by polite compliance with requests.\n\nSmart mouthing a cop is grounds for an instant vehicular safety check looking for ANYTHING that is grounds for a ticket.",
"Because it's an admission of guilt. That way, if you later decide to challenge the ticket, the cop can say that you admitted guilt on the spot.",
"Police are supposed to catch bad guys. If a police officer can get a bad guy to tell him what bad thing they did, the police officer can tell the judge what the bad guy said. When the bad guy says what he did wrong, they call it a confession. \n\nIt would be like if it were your job to catch someone stealing cookies, and tell on them to a grown up. Maybe if you thought you saw crumbs on someone's face, you would think they stole cookies, but you might not be sure. But if you ask them why they have crumbs on their face, and they tell you \"it's probably because I ate cookies,\" then you could tell a grown up what the person who stole the cookies said. ",
"I've been pulled over maybe 6 times in the last 14 years and never once had that question asked to me...",
"They want you to incriminate yourself. If you say \"oh sorry I think I was speeding\" first they know you're not going to make a stink when they write you a ticket, and you won't have grounds to fight it. \nSame reason they go \"do you have any drugs in the car?\" If they smell weed or something, makes their job a piece of cake. ",
"Hoping that one dude says \"because you know I killed Hoffa?\"",
"I don't think they have ever asked me that. It might just be a TV thing. Usually they ask for registration and license and say I was dragging some kid behind my car",
"Used to be a cop and it's done because sometimes people tell you a different crime to the one you pulled them for.\nE.g. pulling them over for not wearing seatbelt but the guy says yeah because I was on my cell phone.",
"Then they can put in their report that you admitted to the crime at the scene and then you automatically lose if you bring it to court unless you can prove the cop was lying (good luck with that). That's why you're not obligated to say anything to the officer.",
"Edit: this post was locked way too soon. We're cops with thick skin, we can handle it. Sorry to those I didn't get to answer your questions. \n\nLaw enforcement here. Such a question is done for a number of reasons. \n\nFirst off and probably most important is to establish a dialogue to accertain the persons level of nervousness. Almost everybodies nervous when they get pulled over, however, through experience you quickly start to tell the difference between the type of nervousness that's \"oh shit, I'm about to get a ticket\" and \"fuck, I hope he doesn't find the brick of cocaine in the trunk\" and most importantly \"should I pull out my gun and shoot this pig\" this question usually leads to follow up questions and gives you a baseline of what type of person you're dealing with really quickly and if they might be a threat and if you need to call for backup. Please understand that we may ask you silly, even obvious questions. And sometimes people get really offended when asked where they are going. We don't give a shit where you're going personally, we are painting a picture trying to decide if you're engaging in something more than a simple traffic stop or if you're about to stick a gun in our face. I have asked people what they have for breakfast. It's all about that baseline and observing people's responses to questions they won't usually lie about, vs questions they will lie about. \n\nSecondly, as some have already said, it puts you on the spot and might elicit a confession. As police, we have a lot of encounters with a lot of people and when we get called to court which is sometimes months down the road, most of the time we only have our notes to remind us of these traffic stops (who has time to pull and watch dash cams for a simple traffic ticket that your salary isn't dependent on). If someone comes right off the bat and admits they were speeding, you write that in your notes and at court you get to say, I don't recall our conversation but according to my notes, the person admitted they were speeding. Boom, guilty. \n\nAnother thing, which is probably more of a preference thing, you want to get an idea on what the persons attitude is. As a police officer (and I'll be honest, some take a long time to realize this, some never realize it) the biggest power you have is the power of discretion. Personally, I always took the attitude of 'what did the person do to get themselves in this situation, and what kind of response is needed from me to get them to correct it\" \n\nSo what I mean by this, when you pull over somebody and they start to downplay why you pulled them over, you're obviously going to have a measured response against that. For example, you pull somebody over in a construction zone for speeding. They start telling you something like, \"well I didn't see any workers\". That's somebody that NEEDS to see a ticket, plus the double fine that construction zone usually brings. That's somebody that clearly doesn't realize how many construction workers and other personnel die every year because of people like them. Where as if somebody responds like, \"yes I'm sorry. I realize I was going to fast in a construction zone, I got complacent\", you can say to yourself that they probably feel bad enough getting pulled over and may likely, at the very least, slow down in the future going through construction zones, so you can just give a simple warning or at least not tack on the construction zone enhancement. \n\nMost cops do have a pet peeve though. For example, children jumping around in a vehicle. Don't give a damn want the excuse is, your getting a ticket Everytime. Seat belts and car seats. No other excuse is getting you out of that one. I can't even start to get into how horrifying any type of crime scene is when it involves children, especially motor vehicle accidents. ",
"NJ cop here. I'm fairly new, and we were advised in the academy not to ask if they know why you pulled them over. It's not a game, you're there to try to correct whatever behavior they were doing when you decided they needed to be stopped. \n\nSome people will say things like, \" I'm sorry I know I was speeding\" or \"I'm sorry I tried to make the light\" before I can even introduce myself let alone tell them why I pulled them over. Those people clearly know and they admit they fucked up and I tend to feel that just the act of me pulling them over gave them the Oh Shit feeling that will correct that behavior. \n\nOn the other hand, sometime I'll pull someone and they will say \"oh I thought the light was yellow.\" Etc... I'm VERY lenient with pretty much all traffic infractions. Speeding, at least 15 over even in a 25. Traffic light? It needs to be dead red before someone is even part of the way in the intersection. When I tell someone why I pulled them and they say they thought it was yellow or they didn't know they were speeding.... BS. \n\nI'm very lenient with tickets too. I received MANY when I was younger (10+ years prior to being hired) so I know how much it sucks. I'll probably be more inclined to let something slide if someone is honest and apologetic vs playing dumb. \n\nTLDR, am cop, don't ask that question. Be honest and apologetic vs playing dumb. ",
"You wouldn't believe the amount of times in the jail I've caught someone smoking something or about to do a line of crushed up pills and asked, \"what was the white powder?\" And I get a response like, \"oh man, it was just some Librium.\"\n\nDude. You don't have to admit that you were improperly handling medicine. You just did my whole job for me. Just say idk or something. ",
"Another question that I've seen on Cops and Live PD is, \"you got anything illegal in the car like drugs, knives, guns, or dead bodies?\" The dead bodies comment is supposed to be a joke. Apparently the officer gauges your nervousness by observing your reaction to the comment. Someone who laughs at the comment appears to not be nervous while someone that does not laugh at the comment might be nervous about having any of the aforementioned items. ",
"1- To see if you'll admit to a crime\n2- It makes you less argumentative if you've already admitted to an infraction, like speeding or broken taillight.",
"It's a strange one. They are trying to get you to confess. But they are also seeking validation. \n\nI was pulled over late night. At xmas. Policeman asked why did I pull you over. I said I've got no idea. Genuinely. He noticed my wife and kid asleep in the back seat and his tone changed. He thought I was some boy racer being an arsehole. \n\nHe called in my plates etc. Came back to me and said he saw me run a red light. I had to explain to the policeman that at the certain junction he was at. Where he was waiting. We both had green lights. He had to give way to me and wait his turn. \n\nNevilles cross in Durham if anyone is interested. \n\nBe polite. Tell the police the truth. Remember in England there are cameras everywhere. If you fucked up admit to it. If you know you didn't. State your case. Police are human. ",
"Because you admit guilt. If you tell him you ran a red light, it is evidence and he doesn't need to make a judgment call. He may have thought you were speeding without radar, but if you tell him you were and how fast you were going then you admit guilt immediately. It makes it harder for you to fight the ticket and takes him off the hook.",
"The reason is to see if you will self incriminate, thereby making it easier to get a conviction. If you answer \"Because I was speeding.\" then they don't have to prove as much in court.",
"To see if you will self incriminate something new so they can add to your citation. Keep your mouth shut. Be polite. Only offer what they ask for and point out you were buckled before unbuckling to get insurance ID etc. ",
"I have a few friends that are police members. This is a tactic to measure your awareness, honesty and politeness. Depending on the situation, the infraction, the officers mood, and your answer, it could define if you get a ticket or not. ",
"Cuz I'm young and black and my hats real low? \n\nSir do I look like a mind reader, I don't know? \n\nLyrics are probably off since I haven't heard the song in years but whatever lol",
"To see if you might possibly be willing to incriminate yourself. It's got to work at least some of the time, and it probably makes things a whole lot easier for the officer. It's along the same lines as asking, \"Would you mind if I searched your car?\"",
"I've been stopped a few times since I've gotten my license.\n\nI've noticed that they don't ask why they pulled you over in California.\n\nIt's almost always something like this:\n\n > [Cop lights me up, I pull over to the right shoulder (not the left; I'm not an idiot.) Turn on dome light, turn off radio, open driver and passenger window, shut of engine.]\n\n > Cop: Good evening. Can I see you drivers license, vehicle registration, and proof of insurance please?\n\n > Me: Good evening. I have my license in my pocket. My registration and insurance is in my glovebox. [hand them to the cop].\n\n > Cop: Thanks. I'll be right back.\n\n > [Cop spends about 5-10 minutes at his car. Returns with a yellow paper.]\n\n > Cop: The reason I stopped you is that my LIDAR indicated you were traveling at 51 miles per hour coming down that hill back there. The posted speed limit is 40 miles per hour. This is a written warning, not a citation. If you have any questions, there's a phone number right here and the specific vehicle code is right here. Have a good night, slow it down.\n\n-or-\n\n > Cop: The reason I stopped you is that I observed you making a left turn while failing to yield to an oncoming vehicle. I'm citing you for this infraction. Please sign here at the bottom. This is not an admission of guilt. It's a promise to appear at the courthouse listed here on the date and time listed here. If you intend to appear, you'll need to call this number prior to this date and let them know. If you have any questions, there's instructions on the back and there's a phone number right here and the specific vehicle code is right here. Have a good night, and next time, don't cut off a cop.",
"Because they want to test if you did something else illegal they don't know about. Basically trying to double fuck you with 2 tickets. ",
"They want you to confess. It makes the whole thing easier for them.\n\n\"I suppose I was speeding a little.\"\n\n\"I missed that stop sign.\"\n\n\"My registration sticker is expired.\"",
"In case you have 2 problems but they only noticed one of them, you just pointed out the other.",
"I'm a police officer and I really enjoy working traffic. That being said, I look for major infractions like a suspended license, intoxicated drivers, and people blatantly disregarding the safety of others. I say that to say with some authority that many people overthink why a police officer asks certain questions. \n\nA lot of times they are repeating what they have been taught. They might possibly be asking you questions to further investigate the stop, which is the most reasonable answer. The best policy I can give you is to keep your hands where you can see them, turn on an interior light if it is night time, and be honest and polite. Very few police officers I know genuinely enjoy getting tickets. Not long ago, I received a speeding ticket while off duty for doing 16 over on a highway and I accepted my ticket and apologized to the trooper for speeding. At the end of the day, it sucked to get a ticket, especially as an officer, but I was in the wrong. \n\nRemember, a citation for a traffic ticket is a court bond so you don't have to go to jail. You can technically be arrested for something as menial as not wearing a seatbelt. Take your ticket with grace and always remember, the time to argue the ticket is in court, not on the side of the road. \n\n\nTL;DR: Stop listening to the news. Cops aren't evil. Be apologetic and own your mistake and it will go well for you 9 times out of 10.",
"One of two things, depending on the officer:\n\n* He wants you to confess so you have no possible chance of contesting; also, you might confess to something else that he didn't know about, more money for the local government\n\n* He wants to see if you'll be honest and own up, which can sometimes lead to not getting a ticket\n\nOverall, not really worth the risk, let him tell you what he knows. That's my opinion though",
"Because whatever you say will be used against you in a court of law. Your words can be used as an admission of guilt.",
"In high school, my buddy got pulled over in an early 90s Honda Accord coming out of a newer subdivision mid afternoon. Cop asked him if he knew why.. no clue, wasn't speeding. Cop says we've been having a lot of theft of building materials in the neighborhood. \n\nBuddy's like \"yah, you can hide a lot of siding and 2x4s in my small sedan...",
"Georgia Deputy Sheriff - I do a fair amount of traffic stops and don't write a whole lot of tickets but it's my understanding trainers are trying to get law enforcement away from asking do you know why I pulled you over because it puts every body in a bad situation. \n\nMy favorite approach is \"My name is so and so from department so and so. The reason I pulled you over is you were going 70 in a 45, do you have any reason for going so fast?\" You can still talk to people and gauge behavior without starting the encounter in a negative way. The other thing it allows is less time spent at somebody's car where most of the danger is. ",
"It reminds me to the rhetorical questions you would ask a child. Patronising but also smart because it immediately puts the police officer (in this case) in a strong position. It uses their position of authority to gain the initiative.",
"They want you to incriminate yourself.\n\nRoll down the window before the police officer walks up, have your hands on the steering wheel when he greets you, and respond with\n\n\"How can I help you, officer?\"\n\nWhen he or she asks you if you know why you've been pulled over, say you have no idea.\n",
"They're hoping for an admission of guilt to make their jobs easier. \nYou really have no idea why the officer pulled you over, so saying 'no' is honest and to the point. ",
"I ask the question to determine how honest someone is going to be with me. Every time I ask \" do you know why I pulled you over?\", I already know the answer. When I conduct a traffic stop and the person is honest and open with me, I will always give them a break. ",
"Because they want to see if you admit to doing something else wrong. If you were breaking multiple laws at once, you might blurt out one of them, not realising that the cop has pulled you over for a different one.\n\nFor example, a cop pulls you over, say the line, then you blurt out that your registration is expired and you were supposed to fix it up on the weekend. Then he informs you he pulled you over for running a red, and know he will write you 2 tickets.",
"It puts you in a situation where you either admit guilt and plead ignorance. It gives them a chance to get it over with on the spot.",
"\"Do you know why I pulled you over?\"\n\n\"Why? Did you forget while you walked from your car to mine?\""
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81g4ov | how it is possible to have a cellphone conversation with a person on the other side of the planet in near real time... | How are the signals able to travel so quickly as to seem nearly instantaneous? I would understand if it was light, but aren't cell signals more akin to sound waves? Sorcery I say... | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/81g4ov/eli5how_it_is_possible_to_have_a_cellphone/ | {
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"No, they are radio waves.\n\nSound waves are matter moving and compressing, just like a physical water wave.\n\nLight, radio waves, and the like, are electromagnetic waves that travel at the speed of light."
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43o8k9 | does temple run use gyroscope or accelerometer ? can you explain the differences between them? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/43o8k9/eli5_does_temple_run_use_gyroscope_or/ | {
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"A gyroscope measures orientation (under what angles is your phone being held), a accelerometer measures acceleration (how fast is your phone moving). A game like Temple Run uses your gyroscope, since it has to know if you're leaning your phone to the left or right."
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785m24 | the genetics of haemophilia a. | Why do people get Haemophilia A? What happens at the genetic level that makes suffers bleed so much? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/785m24/eli5_the_genetics_of_haemophilia_a/ | {
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"When you get a cut, it blood can leave at the site of the injury. If this kept happening, it would be bad, because you'd lose a lot of blood. The body has ways to stop this from happening, and we call this clotting. It's the body's way to sort of make the blood less like a liquid and more like a gel, stopping it from running out.\n\nOne way the body does this is through the coagulation (or clotting) cascade. When there's a cut, the cells around the cut release a messenger that basically says \"Ahhh there's a cut!\" This messenger starts the cascade, which is kind of like a pyramid scheme recruiter. It tells 10 of its friends, who each tell 10 friends, who each tell 10 friends, etc. So in a little bit, you have 1,000,000 friends all helping to plug up the injury.\n\nHemophilia A is a problem with one of the \"friends\" that helps to make the stuff to plug up the injury. This friend, (called Factor VIII) is important, because remember this factor recruits other factors to help too, so if it's not there, we miss out on a lot of help to form the clot. \n\nOur genes have DNA, which is the blueprint that tells cells what to build and make - proteins. One of those proteins is Factor VIII. In people with hemophilia A, they have a problem making Factor VIII. Some people have a Factor VIII that doesn't work right, and others just don't make enough of it. Either way, someone with hemophilia A is going to take a lot longer to clot appropriately. \n\nThe gene that tells the body to make Factor VIII is located on the X chromosome. Genetic males typically have one X and one Y chromosome, and genetic females typically have two X chromosomes. For genetic females, if they have one X that is normal and one X that carries the hemophilia A gene, their good X chromosome can make enough Factor VIII that they're fine. But for genetic males, the Y chromosome doesn't have anything for Factor VIII, so their single X chromosome makes a faulty Factor VIII (or not enough Factor VIII), leading to hemophilia A. This is why hemophilia A is much more common in males than females - genetic females would need both X chromosomes to have the affected gene.\n\nA treatment for people with hemophilia A is to inject them with the clotting factor that they lack, in this case, Factor VIII. Other types of hemophilia are missing other factors - type B is missing Factor IX and type C is missing Factor XI.\n\nLet me know if you have any questions! Happy to explain anything at a more advanced or more basic level :o)"
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d4e1q1 | how/why do people get tingles and some don’t on asmr | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/d4e1q1/eli5_howwhy_do_people_get_tingles_and_some_dont/ | {
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"It is unknown because as of yet we don't know what precisely creates ASMR so we can't say why some do and some don't get it at a particular time, however it may be related to childhood and the relaxing sound or environment that was experienced at the time so making what each person finds stimulating their ASMR different because they had different childhood experiences - _URL_0_",
"I might have a minor case of misophonia, because ASMR and the sound of chewing greatly annoys me"
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1xak4c | how is there wifi on buses (ie. megabus) and not on airplanes? | Are planes just too high to access towers on the ground? Is that even how buses do it?
THANKS!! | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1xak4c/eli5_how_is_there_wifi_on_buses_ie_megabus_and/ | {
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"There is WiFi on many planes. The reason there wasn't for a ling time after buses got it is for safety concerns.",
"Some planes have wi-fi. [It ended badly.](_URL_0_)"
]
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|
45j1fe | difference between microcontroller and microprocessor | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/45j1fe/eli5difference_between_microcontroller_and/ | {
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"text": [
"A microcontroller is a small computer on a single integrated circuit containing a processor core, memory, and programmable input/output peripherals.\n\nA microprocessor is just a processor. It is a component piece of a larger computer rather than a computer by itself.",
"Microcontrollers emphasise I/O, often with low power consumption and in rugged environments.\n\nA microcontroller might struggle with, say, beating you at chess or [image processing](_URL_0_), but microprocessors are available that are much more powerful. You’ll need to attach more chips to your microprocessor if you have a lot of sensors or servos, though—unless you get a system on a chip (SoC) that has those features built‐in to the same package.\n\nLike you’re five: a microcontroller works at the post office, handling thousands of letters and parcels. A microprocessor works at city hall, making the big decisions. If your mail person and mayor switched places for a day, neither would get anything done.",
"A microcontroller has more stuff integrated on-chip. It's designed to be built into some dedicated piece of electronics— maybe it runs your microwave oven, a keyboard or mouse, washing machine, or maybe it controls a subsystem of a larger computer. Many microcontrollers don't need any external components once they're programmed, just power and a connection to whatever sensors/actuators they need to do their jobs. They have clock generators, volatile and nonvolatile memory, and a bunch of peripherals that might be handy for interfacing with the outside world, all manufactured on the same chip.\n\nA microprocessor \"just\" has the CPU— the machinery that executes code— and some tightly-coupled stuff like caches and memory controllers. A microprocessor like you have in a desktop computer requires a *lot* of support circuitry just to run, plus bunches of stuff like RAM, a bios, peripheral controllers, bus interfaces, etc., all of which might be on separate chips. But it's designed for performance, capability, and expandability rather than price and compactness.\n\nSomewhere in between are \"systems-on-chip\", or SoCs. Like microcontrollers, these have a bunch of useful/necessary things built in, but still have a few major components like memory or power management off-chip. They're often used in things like phones or tablets, where compactness is important but you need more performance than a microcontroller will usually give you.\n\n",
"The shortest explanation I can think of is that a microprocessor *is the main component of* a microcontroller, which also has additional memory, input/output capabilities, and so on.",
"You can discard the micro from the front of both words to get a clearer picture. A micro-\"controller\" is used to control something, where something is generally a machine. It is in fact a small computer with the capacity to communicate to circuitry. A Micro-\"processor\" is a computer chip designed to execute instructions given to it. These chips form the basis of computers (and micro-controllers). ",
"The MMU which stands for the Memory Managing Unit. \nYou can install an actual OS onto a microprocessor-based system. "
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