q_id
stringlengths 5
6
| title
stringlengths 3
296
| selftext
stringlengths 0
34k
| document
stringclasses 1
value | subreddit
stringclasses 1
value | url
stringlengths 4
110
| answers
dict | title_urls
sequence | selftext_urls
sequence | answers_urls
sequence |
|---|---|---|---|---|---|---|---|---|---|
1jgfoe | space elevators | How does the concept of a space elevator work?
How would we build one, and how much would it cost?
What would it be made out of?
How can something be simultaneously be tethered to the earth and orbiting at the same time?
What would be the scientific use of such a device?
How close are we to being able to make one? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1jgfoe/eli5_space_elevators/ | {
"a_id": [
"cbefkab"
],
"score": [
2
],
"text": [
"Place an asteroid or a space station in geosynchronous orbit, preferably over the equator. At the same time and at the same rate, extend two cables from the asteroid: a cable down toward the Earth, and a cable up away from the Earth. Assuming the cable is strong enough (carbon nanotubes might have the necessary tensile strength), it won't fall down. Why? The segment of the cable below the asteroid would obviously fall down if you cut it at the asteroid (that piece of cable isn't going to stay in orbit; its orbital speed is too low). The segment of cable above the asteroid would be flung off into space if you cut it at the asteroid (the orbital speed of that piece of cable is much too fast). *The two segments of cable balance each other.*\n\nOf course, we don't yet have a material in quantity with enough tensile strength. But we will someday, which will make a space elevator very attractive: energy can be recovered from descending loads to raise the ascending loads. Even if you didn't do that, the energy cost to raise a load to orbit is but a fraction of what it costs with rockets. Of course, even if the elevator cars ascend/descend at supersonic speed, say a thousand miles per hour, it would take a full day to make the trip up or down.\n\nSpace elevators have appeared in a number of science fiction stories; a classic novel about the construction of one is Arthur C. Clarke's *The Fountains of Paradise.*"
]
} | [] | [] | [
[]
] |
|
7nvor7 | sodium fluoride replenishing phosphorus and calcium in teeth. | How does Sodium Fluoride replenish phosphorus and calcium in teeth if the compound has neither of these chemicals? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/7nvor7/eli5_sodium_fluoride_replenishing_phosphorus_and/ | {
"a_id": [
"ds4up0x"
],
"score": [
6
],
"text": [
"It doesn't. The fluoride replaces the calcium, replacing hydroxyapatite (the hard calcium- containing mineral that makes up most of your enamel) with fluorapatite. This is actually a good thing - fluorapatite is much harder than hydroxyapatite, and resists corrosion from acids better. That *does* help protect the calcium you still have left, though. You're not replenishing your calcium, you're replenishing your enamel. \n\nImportantly, this only works as the hydroxyapatite is breaking down. The component chemicals have to be present to reform into enamel, which is why once your enamel is gone, it stays gone. It's a bit like fixing a hole in a brick wall with new, stronger brick, but you didn't bring your own cement so you can only use the cement that's there and when that's gone the hole can't be patched. "
]
} | [] | [] | [
[]
] |
|
4io1e6 | how do big cooperation like microsoft and apple, protects the source codes of their operating systems from leaking | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4io1e6/eli5_how_do_big_cooperation_like_microsoft_and/ | {
"a_id": [
"d2zo3b3",
"d2zqlge",
"d2zub52"
],
"score": [
13,
2,
2
],
"text": [
"Most software that you use on your PC or mobile device is *compiled*, meaning that it's been converted from the original source code (full of comments, explanations, and human-readable variable names) into machine code (that only contains the instructions a computer needs to execute the program).\n\nHowever, it's important to understand that this doesn't keep the software completely secret. Any experienced programmer can *decompile* the software and figure out exactly how it works, it's just a lot more tedious and slow to do so without access to the original source code. However, programmers reverse-engineer how operating systems work all the time, in the course of trying to figure out why they're seeing obscure bugs, and malware authors often do the same in their quest to find bugs to exploit.\n\nThat said, companies still do want to protect their source code. The source code is only stored on managed company computers at their engineering offices, or on laptops that are fully managed and monitored by the company, never on employee personal computers or laptops. That minimizes the chances it's accidentally leaked.\n\nWhen some of the source code does leak, they can use legal means to protect it. Since it's copyrighted, they can sue anyone who tries to share it without permission.\n\nFinally, they have the advantage that the source code is *huge* - many tens of millions of lines of code. That's not something you can hide very easily. The total size of the whole codebase is at least as much as downloading a HD movie.\n",
"You're begging the question that they want to keep the source code secret. You can get the source to Windows if you sign up to their developer program. Apple's I'm not sure, but they're based on BSD, which is an operating system that's open source. \n\n",
"This comment has been overwritten by an open source script to protect this user & apos;s privacy. It was created to help protect users from doxing, stalking, and harassment. \n\n If you would also like to protect yourself, add the Chrome extension [TamperMonkey](_URL_2_), or the Firefox extension [GreaseMonkey](_URL_1_) and add [this open source script](_URL_3_). \n\n Then simply click on your username on Reddit, go to the comments tab, scroll down as far as possibe (hint:use [RES](_URL_0_)), and hit the new OVERWRITE button at the top. \n\n Also, please consider using [_URL_5_](_URL_4_) as an alternative to Reddit as Voat does not censor political content."
]
} | [] | [] | [
[],
[],
[
"http://www.redditenhancementsuite.com/",
"https://addons.mozilla.org/en-us/firefox/addon/greasemonkey/",
"https://chrome.google.com/webstore/detail/tampermonkey/dhdgffkkebhmkfjojejmpbldmpobfkfo",
"https://greasyfork.org/en/scripts/10380-reddit-overwrite",
"https://voat.co",
"Voat.co"
]
] |
||
1mbmus | when is it okay/not okay to sample a song? | This can include things like mashups, bootlegs, remixes, etc | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1mbmus/eli5_when_is_it_okaynot_okay_to_sample_a_song/ | {
"a_id": [
"cc7n9t1",
"cc7qtk9"
],
"score": [
2,
3
],
"text": [
"If you don't want to read a summary here's an article from wikipedia:_URL_0_\n\nWhen using a sample in a new song you are really just taking a little part of a preexisting song and reusing it. This is fine, as long as you have contacted the orginal artist/label and gotten permission (either through good will or purchase).\n\nBootlegs arent really legal.",
"It is always okay to sample a song.\n\nHowever, it might be illegal to distribute copy written material. Generally if you wanted to sample a song, then sell it you would have to get the permission of whoever owns the copyright on the song (usually a record label). Usually securing that permission involves paying money, called \"royalties,\" which is why basically how people make money in the top 40 music industry.\n\nHowever, if you make a mash up and post it on soundcloud or YouTube or something and aren't making any money off of it, pretty much no one will care.\n\nHope that makes sense"
]
} | [] | [] | [
[
"http://en.wikipedia.org/wiki/Legal_issues_surrounding_music_sampling"
],
[]
] |
|
205edq | how does the fashion industry work? how does haute couture, which mostly looks hideous to my eyes, become fashion of the next generation? (or does it?) | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/205edq/eli5_how_does_the_fashion_industry_work_how_does/ | {
"a_id": [
"cfzx8i7"
],
"score": [
3
],
"text": [
"It generally doesn't, much of what you see in those sorts of fashion shows are just too weird and/or expensive to really see any sort of wide adoption in general fashion. But a lot of times those ridiculous looking designs are just extreme demonstrations of a more basic idea, and that more basic idea might find its way into regular fashion in a more subdued way. \n\nThis sort of thing doesn't just happen in the fashion industry either. Car companies are regularly showing off \"concept cars\" that they don't intend to actually mass produce and sell, but rather just to demonstrate various ideas and generate some buzz. Some architecture magazines are full of renderings of crazy buildings that won't actually be built, but their designers wanted to explore some ideas and share some of their thought processes.\n\n"
]
} | [] | [] | [
[]
] |
||
1kidoz | soap kills 99.9% of germs, why doesn't it work when ingested to kill the germs inside you? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1kidoz/eli5_soap_kills_999_of_germs_why_doesnt_it_work/ | {
"a_id": [
"cbp8ltc",
"cbp8rfd"
],
"score": [
53,
2
],
"text": [
"Soap doesn't kill germs at all. Soap is what's called a *surfactant,* which is a chemical that makes it easier for things to dissolve in water. When you wash your hands with soap, it's actually the action of rubbing your hands together and running water over them that removes stuff, including bacteria and viruses.\n\n*Disinfectants* kill germs. We can broadly divide them into two categories: Ones that would make you sick if you consumed them, and ones that wouldn't. We use disinfectants that *don't* make you sick all over the place, particularly in drinking water.\n\n*Antibiotics,* on the other hand, are chemicals which are specifically used to kill harmful microorganisms in your body. What's the difference between an antibiotic and a disinfectant? An antibiotic can be absorbed by the body and transported into your *lymphatic system.* Your lymphatic system is that part of your body that's responsible for moving infection-fighting agents to areas of infection. In order for an antibiotic to reach the infection that's making you sick, it has to \"hitch a ride\" on your lymphatic system to get there. Antibiotics are chemicals that can do that, while disinfectants aren't.",
"First, soap doesn't kill germs, it just helps wash them away. Secondly, digestive enzymes, stomach acid and other stuff just ruins the ability of soap to be soapy. Third, why would you want to eat soap?"
]
} | [] | [] | [
[],
[]
] |
||
do43vg | why is it that when you put pressure on your eyes (like if you were laying down in a certain way that put pressure on your eyes) then you take the pressure off and look around everything is blurry? | I notice it especially when im in bed with the lights off then go to grab a water or something then my alarm clock looks burry af or if i look at my phone i can barely see my screen | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/do43vg/why_is_it_that_when_you_put_pressure_on_your_eyes/ | {
"a_id": [
"f5jtm3p"
],
"score": [
6
],
"text": [
"Your eyelids have a bunch of glands on them that secrete oil. If you press them (or your pillow for that matter) you're squeezing it out like a tube of toothpaste. So while it spreads over your eye and drains, your looking through an oily surface."
]
} | [] | [] | [
[]
] |
|
2ei5du | why do we pace when anxious/stressed? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2ei5du/eli5_why_do_we_pace_when_anxiousstressed/ | {
"a_id": [
"cjzqces"
],
"score": [
2
],
"text": [
"Anxiety makes us want to take action (to fix whatever's winding us up). If we have no action to take, we just walk around to work off the extra action energy."
]
} | [] | [] | [
[]
] |
||
edyg0h | if a fall from a great height into water is like landing on concrete regardless of how you position yourself, why are divers unharmed when diving from 100+ feet? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/edyg0h/eli5_if_a_fall_from_a_great_height_into_water_is/ | {
"a_id": [
"fbm4hmx",
"fbm7vb2",
"fbmbbto"
],
"score": [
8,
2,
7
],
"text": [
"For it to be like concrete no matter how you position you have to go up to a few hundred feet. If you belly flop at 100ft you will probably kill or at least seriously injure yourself. Professional high divers go in hands or feet first which cut through the water and pushes it out of the way.",
"It's about water tension. If you can disrupt the water tension then you theoretically could jump from any height and be fine.",
"This is a matter of [surface tension](_URL_1_). Water is a very unique and, sometimes, trippy molecule. It's got a low molecular weight, but is still a liquid at room temperature due to the fact that its molecules will create temporary bonds called [hydrogen bonds](_URL_0_). \n\n\nThey aren't full on covalent or ionic bonds, but rather about electron distribution for energetic stability. Hydrogen molecules prefer donating their electron to empty their valence shell and oxygen needs 2 electrons to fill its valence shell. When this happens, hydrogen carries a slightly positive charge and oxygen carries a slightly negative charge, creating polarity on the molecule. So neighboring water molecules will fix themselves to each other with the hydrogen and the oxygen atoms causing the molecules to be tighter/closer together. \n\nThis is the state of chemical equilibrium for water molecules, btw. It also creates a relatively solid surface due to the bond proximity. You don't need much force to pierce/break up a single hydrogen bond, but breaking up a fuck ton of them requires a bit of pressure, aka force divided by the area. **If you dive in with a small point of entry, you pierce the water because your force is spread over a small area (of hydrogen bonds). If you belly flop, you are applying less force per unit of area while also interacting with many, many, many, many more hydrogen bonds.** \n\nOh yeah, did you know that those bonds can distribute force across the lattice/surface? That's why a belly flop hurts and why one from a greater height can kill you."
]
} | [] | [] | [
[],
[],
[
"https://en.wikipedia.org/wiki/Hydrogen_bond",
"https://en.wikipedia.org/wiki/Surface_tension"
]
] |
||
2ub296 | how do millions of votes get manually counted in less than a day in the australian election when every single vote needs to be shipped to the capital? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2ub296/eli5_how_do_millions_of_votes_get_manually/ | {
"a_id": [
"co6rnnx"
],
"score": [
40
],
"text": [
" > The counting of votes is known as the scrutiny. The scrutiny commences on election night in each polling place after 6pm when the polling place has closed. Both ordinary ballot papers and pre-poll ballot papers completed by voters within their division are counted on election night. The scrutiny is usually observed by scrutineers nominated by the candidates. \n\nSource: _URL_0_\n\nIt appears they aren't moved anywhere but rather are counted in situ with results electronically communicated to a \"Virtual Tally Room.\""
]
} | [] | [] | [
[
"http://www.aec.gov.au/voting/counting/"
]
] |
||
411c71 | why do long camera lenses have so many individual lenses inside them? how does that work? | This one was kind of hard to ask since the word lens is used for both the overall assembly and the individual optical elements inside it. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/411c71/eli5_why_do_long_camera_lenses_have_so_many/ | {
"a_id": [
"cyytr4t",
"cyytra2"
],
"score": [
4,
4
],
"text": [
"Photographers call the individual pieces of glass elements. \n\nThey're there because each curved surface allows the designers one more degree of freedom to correct optical flaws (go look through a cheap magnifying glass to see how many optical flaws a single element can have). However, each surface increases the light reflection (and reduces the contrast of the final image) which limited designs for many years. Until a Zeiss lens designer realized that old tarnished lenses took better pictures and they worked out coatings that reduce the amount of light reflected, as these coatings improved, reflections have gotten very low on each element and designs can become quite complicated, which allows the final image to be well corrected for many optical flaws. \n\nAlso, technically, short focal length lenses frequently have the most elements (because they must bend light so far which means more corrections in the remainder of the lens). ",
"Ideally what you want out of a lens is for all of the light that originates at one point in the scene to wind up at one point on the film (or CCD, which is the digital equivalent), regardless of where on the lens the light hits.\n\nA single thin lens where the front and the back are both sections of a sphere will accomplish this *pretty* well. The math works out perfectly if you assume that the light gets bent once at the center of the lens, like in [this](_URL_0_) graphic.\n\nThe problem is that light gets bent at both surfaces of the lens, which means that, for example, the ray that was supposed to pass through the center of the lens (the middle one in the graphic) will actually be deflected downward by the first surface of the lens (much like the top two rays), then it'll overshoot its exit point and be deflected back upwards (relative to its original path) by too much and will land at the wrong point. When light passing through different regions of the lens wind up at different points you don't get a sharp image—the light is \"smeared out\" across a region of the image, which is why out-of-focus images are blurry.\n\nThis isn't an issue of focus, though. You get the same kind of blur if you put your film (or CCD) at the wrong distance from the lens (which is why camera lens housing get longer as you change focus), but there *isn't* a place to put your film when you consider the imperfections of a single lens.\n\nPutting a bunch of lenses in series allows you to have individual lenses that are working to correct things like this. They could use fewer, but there's another issue: not all colors get bent in the same way by a lens. This is why a prism is able to separate white light into a rainbow. When light hits the first surface of a lens the different colors start to diverge. Keeping the individual lenses small means that the light exits the lens and is (hopefully) realigned. Cameras that do this poorly exhibit \"chromatic aberration.\"\n\nAll of that deals with focus. There's also the issue of zoom, which requires another set of lenses. The same considerations apply, though. "
]
} | [] | [] | [
[],
[
"http://www.physicsclassroom.com/Class/refrn/u14l5c1.gif"
]
] |
|
fcpj39 | why do our ears always hear our name distinctively even in a noisy place? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/fcpj39/eli5_why_do_our_ears_always_hear_our_name/ | {
"a_id": [
"fjc9wbb",
"fjcah6e",
"fjcclfr",
"fjccqdo",
"fjcd80v",
"fjcdnab",
"fjcekhe",
"fjcg2yq",
"fjcjgp3",
"fjckiu9",
"fjcl8vu",
"fjclbdr"
],
"score": [
7,
1633,
1605,
11,
9,
45,
4,
119,
3,
36,
31,
2
],
"text": [
"Because we're trained to respond to our name for the sake of safety, amongst other things?",
"I took some Psychology classes in University and I believe it has something to do with the Cocktail Party Effect.\n\nSimilar to being at a party, with lots of noise, the brain is able to filter out that noise of the party and focus onto something specific, such as your named being called out among that noise. \n\nBasically our brains have the ability to chose which noises (stimuli) are important among many others.",
"As the other user already stated this is usually considered as part of the cocktail party effect, the reason it happens is because of the way our brain perceives information and “chooses” what to pay attention to. \n\nHearing your name has a relative small threshold and therefore bypass the filter that your brain uses when determining what to pay attention to. Once you hear your name attention is diverted to that sound. \n\nUncommon or unimportant words to you have a high Threshold and won’t trigger your brain to pay attention to them.",
"I'm not a psychiatrist, I just read this somewhere. Imagine walking through a mall. you can't possibly respond to every stimulus there, but the brain is ridiculously good at filtering out information out of necessity and will only subconsciously respond to things that are inherently pertinent to you, so you'll notice someone looking at you or calling your name, or someone fighting nearby (survival instinct), you'll notice, but you won't remember the faces of people you walked past and won't hear conversations you're not actively listening to, etc.",
"I don't.\n\nQuite the opposite, in fact. \n\nVery many utterances -- \"ah!\" \"Huh?\" \"Nah!\" \"Spa!\" -- that I hear in noisy places make me *think* I'm hearing someone say \"Rob!\" and confuse the shit out of me. \n\nIf *only* I'd been named Quentin.",
"In an effort to ELy5. Imagine your brain working two different main jobs- half focusing on the task at hand, and the other half focusing on threats to your safety. The half doing threat assessment is always on- even when you’re asleep (though at reduced power when sleeping). It’s job is to use all senses to keep your heart beating and lungs breathing- and to provide the other half (task at hand) the information it needs to keep doing its job, that is- staying alive. Any information coming to the threat assessment is filtered as “needed” or “unneeded” information. All needed information (your name) is thrust into the task at hands focus, so it can evaluate that information more throughly. Unneeded information is simply let through the filter.\n\nEdit: also known as the Cocktail effect, as others have said.",
"There are alot more neural connections linked to your name than any other sound cue, so you immediately recognise it.",
"Years and years ago had some friends notice this while having lunch at E3. Sitting around chatting when through the din of the crowd the only word that could be recognized was \"EverQuest\". Ever since then we've referred this phenomenon as \"blah blah, EverQuest, blah blah\".",
"Your ears capture all of the sound coming in even whilst you're on autopilot. On autopilot, you aren't listening and the parts of the brain that process the signals act independently and automatically filter out the bits of information that they think will be irrelevant.\n\nSo although you're constantly \"hearing\" everything, these parts only actually switch off autopilot and grab your attention when something passes through the filter e.g. your name.\n\nOne benefit of this is that the rest of your brain remains free to process other information the rest of the time.\n\nOne drawback is that this filter never stops expanding. It can eventually start filtering out things that you might actually want to turn your autopilot off e.g. your morning alarm. So although you might not have hearing loss, picking up on external queues becomes a more conscious effort.",
"It's your brain, not your ears. You filter out all kinds of incomprehensible noise all the time. Your name is instantly familiar to you and is therefore not filtered out.",
"Reticular Activating System. I know a lot of people on here are talking about the Cocktail Party Effect, and using computer or internet analogies but it's actually the RAS, a small part of the brain which is a bundle of neurons that are responsible for essentially, (in laymans terms), filtering things out and letting important things through. It not only works with your own name but anything that is important to you, like the names of your children. It's also the reason why, when you learn a new word, you hear that word being used everywhere, or in the case of one freind who bought a new Subaru, began to notice Subarus everywhere. \n\nEdit: grammar, spelling.",
"I am not a psychologist or physician - so the other explanations might be more correct. \n\nI once read about this phenomenon and the only reasonable but completely astonishing conclusion was that you are listening to all the conversations you hear all the time and it is just a mechanism in your brain that prevents all of it from reaching your consciousness (because consciousness does not have the required capacity to process all of it). When you hear your name the other discussion becomes conscious for you. \n\nYou can try this. If you are at a restaurant you can listen to the conversation on the next table while missing what is going on at your own. Your ears don’t change anything about what they are doing, so this must be happening in your brain. \n\nReading this idea blew my mind at the time. On the other hand it explained to me why working in a place with many distractions is so hard for me."
]
} | [] | [] | [
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[]
] |
||
2s8bdj | will someone please explain a "union" to me? | I used to work at wal-mart & they told us unions were bad blah blah blah, what are they and how are they bad? (I'm assuming they're not bad considering walmart said so & walmart is evil). Ive googled this question but can't find a satisfying answer. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2s8bdj/eli5will_someone_please_explain_a_union_to_me/ | {
"a_id": [
"cnn2ydn",
"cnn2ygl",
"cnn3vin",
"cnn3vqx"
],
"score": [
3,
4,
2,
11
],
"text": [
"When a group of workers, usually inside the same company or field of work, collectively form an organization to represent them in labour disputes and to provide them with protections from any abuse by the employer.\n\nGoing on strike is usually a union decision.\n\n",
"A union is a group of workers united to achieve a common goal. If a single worker attempts to negotiate with a multinational corporation for better pay, that worker will get fired and the company moves on as if nothing happened. If ALL of the workers bands together into a union and collectively negotiate with the company, the company must listen to the demands because the company cannot fire all of its workers.",
"Trade unions help to raise both wage and skill levels. They are associated with a strong middle class.",
"As for the other part of your question (\"... and how are they bad\")\n\nUnions can be viewed as bad for a couple of reasons. From a businesses perspective, they are bad because they force the business to spend more than they strictly \"have\" to on their employees, because they give \"replaceable\" employees (entry level, doesn't require much in the way of per-existing skills, whatever) more power.\n\nTake, for example, a warehouse. There's 100 floor employees, and they all make $8/hr. If one floor employee says \"hey, I work hard, I deserve $10 an hour!\" Well, the boss just says \"nope.\" and if the employee keeps making a big deal about it, the boss says \"not just nope but you're fired.\" The warehouse now has 99 employees and just needs to hire someone to replace the guy who got fired.\n\nNow look at that same warehouse with 100 floor employee, only this time, they all belong to a union. The union rep engages in what's called \"collective bargaining\" and goes up to the boss and says \"hey, we work hard, we deserve $10/hr.\" The boss says \"nope\" and the union goes on strike and nobody works. Nobody works, nothing gets done, and the company loses tons and tons of money. The company realizes the employees are serious, does the math, and realizes it's cheaper and easier to pay everyone $10/hr than to have to fire everyone (and pay their unemployment!), hire 100 new people, train 100 new people (difficult, because everyone who knows what they're doing has been fired), and get back up to speed. So the company gives everyone a $2/hr raise, costing the company $200/hr more than if there wasn't a union.\n\nSimilarly, Unions can bargain for better benefits (retirement packages, better insurance) and bring grievances forward (like bad bosses, dangerous but not illegal working conditions) in such a way that the company has to pay attention to it.\n\nAnother thing unions do, usually professional unions like a plumbers union or painters union, if offer a uniform skill assessment. You can be guaranteed that every member of the plumbers union has at least a minimum skill level and experience and a certain amount of insurance in case they do screw up -- and if they do screw up, you have a 3rd party to take *your* grievance to, which has their own ways of censuring their members short of actually taking them to court... and if you do take them to court, they have their own lawyers to help protect their members from stupid lawsuits -- because the union has deeper pockets than any given plumber, and thus can hire better lawyers or have entire law firms on retainer.\n\n \n\nUnions can, however, become *too* powerful. As the saying goes \"power corrupts,\" and this is usually what companies like wal-mart and anti-union politicians bring up. Take that warehouse example. Say they keep bargaining, and make it almost impossible for someone to get fired, and they keep bargaining, and keep raising the wages, and increasing the benefit. Eventually it can get to the point where the company literally cannot afford to give into the unions demands, but they also cannot afford to *not* give into the unions demands. Or the union can get into shady business, essentially forcing employees to join the union, like a protection racket.\n\nUnions can also result in absurd work rules. Like in the film industry, say you're doing a commercial shoot. The director wants one of the lights moved 5 feet to the left. So you have to call over the light guy (part of the light guys union) to move the light, because if you don't, the union might boycott your future shoots because you're 'stealing work' from the union guys."
]
} | [] | [] | [
[],
[],
[],
[]
] |
|
sycrr | balance sheet vs. income statement vs. cash statement | What are the differences between the three? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/sycrr/eli5_balance_sheet_vs_income_statement_vs_cash/ | {
"a_id": [
"c4i0758"
],
"score": [
5
],
"text": [
"Income Statement: has all the revenue (sales) and expenses (cost of operating the business) and ends at net income\n\nBalance Sheet: snapshot of your company's assets, liabilities, and owner's equity. \n\nCash Flow Statement: starts with your net income from the income statement and shows the flow of cash in your company - what is the cash that is being spent going toward and where incoming cash (not sales) comes from (i.e. Operating Activities, Investing Activities, Financing Activities). After adding in-flows and subtracting out-flows, you end with remaining cash that goes to your balance sheet. "
]
} | [] | [] | [
[]
] |
|
7iyhnl | how do we make different notes when we whistle? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/7iyhnl/eli5_how_do_we_make_different_notes_when_we/ | {
"a_id": [
"dr2carh"
],
"score": [
4
],
"text": [
"By changing the shape of the hole between your lips, you make the air passing through it move past your lips at different pressure and speeds, which changes the way it vibrates, which is what sound is. "
]
} | [] | [] | [
[]
] |
||
2aahiq | if i point a laser beam at the moon and slightly moved it how fast would it be on the surface of the moon | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2aahiq/eli5if_i_point_a_laser_beam_at_the_moon_and/ | {
"a_id": [
"cit37pd",
"cit3fo7"
],
"score": [
7,
3
],
"text": [
"As fast as you like! The speed of the laser spot (which will be several kilometers wide by the time it reaches the moon) will be equal to the product of the distance from your hand to the moon (about 384,000 km) and the angular velocity (measured in Radians per second) with which you move the laser pointer. Suppose you flick your wrist at a meager 1 radian/second while your laser is pointed at the moon: the spot moves across the lunar surface at about 384,000,000 meters per second. That's already faster than the speed of light!\n\nThis doesn't violate any laws of physics because the laser spot isn't a real object that can carry information or do anything else useful. Nothing \"real\" is moving faster than c, so Special Relativity is unharmed by this experiment. ",
"This video should explain\n\n_URL_0_"
]
} | [] | [] | [
[],
[
"https://m.youtube.com/watch?v=lR4tJr7sMPM"
]
] |
||
3f7p3i | why isn't smoking during pregnancy illegal even though the side effect are well known, and is generally frowned upon in society? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3f7p3i/eli5_why_isnt_smoking_during_pregnancy_illegal/ | {
"a_id": [
"ctm299f",
"ctm2ez6"
],
"score": [
5,
2
],
"text": [
"Because a society can't just make laws for every single behavior it deems unhealthy or negative. ",
"See [this ELI5 from a few hours ago](_URL_0_)."
]
} | [] | [] | [
[],
[
"https://www.reddit.com/r/explainlikeimfive/comments/3f6y40/eli5_why_is_it_legalokay_for_a_clearly_pregnant/"
]
] |
||
7v1cvk | do we know why elementary particles behave like waves / what underlying phenomenon causes it to behave like a wave? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/7v1cvk/eli5_do_we_know_why_elementary_particles_behave/ | {
"a_id": [
"dtos7h0",
"dtovppr",
"dtpkm3t"
],
"score": [
17,
4,
2
],
"text": [
"TLDR: No, we don‘t know per se *why* that happens, rather we observed it and adjusted our theories to it. \n\nFor the longer answer, I think we have to differentiate between the philosophial aspects and the actual physics behind it. Let’s start with the physics: Before quantum mechanics, we just assumed that any particle would behave as just that, a particle, it would the typical properties of a particle such as mass, a position and so on. However, at some point, this theory turned out to be inaccurate. In an experiment called the „Double slit experiment“, we discovered that those small particles behaved in a way that we had never observed with a particle before, but rather like a wave. Following that observation, we were able to condense that type of behaviour and many more into the theory of quantum mechanics, the theory that describes the behaviour of exactly those particles, *„quanta“*. \n\nPhilosophically, it is a whole different question, that I fail to answer exactly. We don‘t know why our universe was created the way it was, but what we do know, is that we as humans can build a foundation in an effort to describe the universe as exactly as possible. ",
"No-no, it don't work like this) \nHumans created physical model of wave and physical model of particle. \nBut reality is much more complex, so it's not that a particle behave like a wave - it's that our model can't explain it. \n\nTheir \"natual\" behavior is something third, that in some situations can behave like wave and in some - like particle. \n\nELI5 example would be something like list of paper, green on one side and yellow on other side. \nDepending on angle to this list you may see it green or yellow, but in reality it's both green-yellow one.",
"We also don't know why the elementary waves behave like particles. Or why we're not using the term \"particle-waves,\" since they have the properties of both waves and particles.\n\nIncidentally, most people imagine water waves or guitar-string waves when talking about \"waves\", but those waves are composed of many particles, not just one. A vibrating Ping-Pong ball may be a more accurate visualization. \n"
]
} | [] | [] | [
[],
[],
[]
] |
||
ezrv5j | why do older cars have a kind of line pattern on the headlights and it is a little blurry while newer cars have nice and transparent headlights? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/ezrv5j/eli5_why_do_older_cars_have_a_kind_of_line/ | {
"a_id": [
"fgp3c3y",
"fgqxc9e"
],
"score": [
28,
2
],
"text": [
"Normal driving light (not high beam and not parking lights) has to be asymmetrical, meaning the beam of light needs to light up the road differently. Towards the middle/traffic, the light has to hit the road sooner than towards the side. This is to not blind the oncoming traffic, yet provide enough light (and give you enough time) to react to pedestrians/bikes/animals that could be on the side of the road.\n\nOne could now think that the lightbulb towards the middle is just pointed lower than the one to towards the outside. But that's not the case. Both bulbs are shining on both sides. Asymmetrical.\n\nOn older cars, this effect was achieved by making lines and making the glass thinner and thicker different places, it creates this difference in where the light beam hits the road (if you know about the lights refraction in glass).\n\nToday, this is done in a much more technical way, thus the lines are not needed anymore (also making it much cheaper to replace a broken headlight glass).",
"The patterns in the lens are actually tiny _prisms_ designed to manipulate _images of the filament_ to correctly illuminate the road. Usually, when people think of prisms, they think of [this](_URL_1_). Yes, that's a prism. But it's only one type of prism. The line pattern you see on older headlamps represent other forms of prisms--prisms used to create _image transformations_ such as flips, rotations, etc. Why do we want to effect image transformations? Keep on reading! \n\n----\n\nWe'll start with [a simplified model of the headlamp.](_URL_0_) The relationship of the filament and the reflector is highlighted by this simplified model: the filament emits light, which is reflected onto the road. \n\nFact: _Images of the filament_ are reflected onto the road. [A car's beam pattern is _the composite of many filament images._](_URL_5_) \n\nExplanation: It's really no different than if you walked into your bathroom and looked at the mirror--the _image of your face_ is reflected back into your eyes, into my eyes since I'll be standing behind you, and even onto the bathroom wall behind you. The only difference is that your face isn't exactly glowing hot enough to _emit_ light, so by looking into the mirror, you aren't really making the wall behind you any brighter. But a filament obviously glows hot enough to emit light, so its reflected image will light up the road. \n\nHowever, just putting images of the filament on the road isn't enough. The filament images [are carefully \"remapped\" by the lens and onto the road.](_URL_3_) Those rectangles represent images of the (rectangular) filament. They're placed at all sorts of locations and orientations. How did we rotate those rectangles?? How did we translate them vertically? How did we translate them horizontally? How did we move them all over the damn place?? \n\nWell, that's where the patterned lens comes into play--those [prisms](_URL_2_) are purpose-made to manipulate the image of the filament. The prisms \"play\" with the filament images to effect the necessary transformations.\n\n----\n\n > newer cars have nice and transparent headlights\n\nAdvances in computational power enabled this. Older headlamps with the patterned lenses mainly relied on simple, paraboloid reflectors--unlike today, where we have _complex freeform_ and often [_segemented_ reflectors.](_URL_6_) Look at all the _segments_ within that headlamp. The reflector surface is broken up into little \"strips\" and each of these strips has been individually tuned to manipulate the _filament image_ correctly without the help of lens prisms. \n\nNow, we can specify the appropriate beam pattern and work backwards into a _complex_ reflector [that manipulates the filament image without the help of a lens.](_URL_4_) The geometric characteristics of each _segment_ can be manipulated to send filament images exactly where they need to go. \n\nSend an optical designer back 40 years without today's powerful computers and such a task--calculating the appropriate geometries for each of these numerous segments--would take literally years if not decades for a single headlamp."
]
} | [] | [] | [
[],
[
"https://i.imgur.com/VLWuNzn.png",
"https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcShjX12oAzh-YvAWHE4vD6cvn7-OufXNR-CPhONEpUrynvYe8Dz&s",
"https://i.imgur.com/9ws7pGj.png",
"https://i.imgur.com/Xu5UL5T.png",
"https://i.imgur.com/76ujd9m.png",
"https://i.imgur.com/RVlaopd.png",
"https://i.imgur.com/1b4JLLh.png"
]
] |
||
1v46j3 | why do all invasive species seem to come from asia, and why don't we hear about north american species of fish/insects/bacteria/whatever causing destruction over there? | It seems like every story I read about a horrible, invasive species seems to involve some species that came from Asia and took hold in America: Carp, Burmese Python, and now [this orange juice disease](_URL_0_). Why do so many of the invasive species that hurt US ecosystems come from Asia, and how come we never hear about a species from North America running amok in Asia?
EDIT: consensus seems to be that there are invasive species that go the other way, we just don't hear as much about them through our media channels. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1v46j3/eli5why_do_all_invasive_species_seem_to_come_from/ | {
"a_id": [
"ceoj6jb",
"ceoj8uj",
"ceojh08"
],
"score": [
6,
2,
3
],
"text": [
"For one thing, the media you're exposed to primarily focuses on what's going on here, because that's what you care about. They don't typically report on incidents that happen internationally unless it somehow effects us here, and for the most part, it doesn't.\n\nSome cases, like SARS, or Bird Flu, you heard about--because these could make their way here and effect us.",
"Perhaps because you read local papers and magazines and restrict your Internet to English language sites. The people writing for those sources are going to write about what is local. There have certainly been invasive species elsewhere. Cane toads in Australia, snakes and/or rats brought to Pacific islands, etc.\n\nFrom today's news about Canine distemper affecting Indian tigers... \"Canine distemper virus, a close relative of measles, is associated mostly with domestic dogs, though it has infected and ravaged other carnivore populations. It brought the US black-footed ferret to the brink of extinction in the late 1970s. In Tanzania in 1994, an epidemic probably introduced by tourists' dogs wiped out at least a third of the 3,000-strong African lion population in Serengeti national park.\"\n\nAs a last thought, perhaps so much of Asia is concerned with combating simple poverty that dealing with an invasive carp doesn't rise to the level of significance needed for widespread discussion.",
"The British introduced rabbits to Australia as food and some escaped. They are still trying to control them and at times there have been hundreds of millions of them."
]
} | [] | [
"http://www.washingtonpost.com/national/health-science/florida-citrus-growers-worry-that-deadly-bacteria-will-mean-end-of-orange-juice/2014/01/12/1391c470-7891-11e3-b1c5-739e63e9c9a7_story.html"
] | [
[],
[],
[]
] |
|
3co98x | why do human beings from only about 100 years ago look so different than human beings today? | I'm not just talking height/weight/build, their faces appear different too. If I'm wrong here let me know, but in looking at very old photos it appears as if people's facial features used to look noticeably different than they do today. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3co98x/eli5_why_do_human_beings_from_only_about_100/ | {
"a_id": [
"csxd37s",
"csxd3zp",
"csxd93s",
"csxdnk3",
"csxhdk6",
"csxj18x",
"csxk6e8",
"csxl7fk",
"csxnu43"
],
"score": [
10,
8,
20,
23,
6,
5,
8,
7,
3
],
"text": [
"The quality of life from 1915 compared to now is amazingly different. If you don't count the war and just look at people in general they were less healthy by far and less well fed. \nInfant mortality in 1915 was was at around 140 per thousand in 1915 its in single figures now. \nWe are a very lucky people who have it amazingly well compared to 100 years ago. ",
"Nutrition has improved a *lot* in the last century. Severe vitamin deficiencies are almost unheard-of in the first world today, but were a major developmental issue in the fairly recent past. Iodine deficiency, for example, was very common and could cause (among other things) mental retardation; today iodine is commonly added to things like salt, preventing such deficiencies. Without any more details to work with, that would be my explanation - if you have an example it might be easier to address.",
"In addition to better nutrition and general health today, the cameras are also better. Depending on how far back you're looking at, people may have been asked to sit or stand still for longish periods of time in order to have their picture taken. Someone standing still for 10 seconds looks a lot different from an quick action snapshot.",
"To add on to the comments already - dentistry played a huge role. Many people's faces look distorted because they have no teeth or have crudely designed dentures in their mouths. \n\n",
"Who was considered attractive and worth taking a picture of changed. There are a lot of people around that look like those people did but they do not get their picture taken anymore so you do not see them in the media which somewhat defines what you consider normal.\n\nThe other comments about nutrition, dentistry and so on are also valid points. ",
"I think about how people react when they know someone is taking their picture. They smile to create a virtual happy situation usually. If you've never been photographed, there may be a few automatic gestures that you haven't learned.\n\nI also like *MayContainNugat's* comment about standing still for a long time to get a photograph. ",
"They don't look different. You're just reacting to the difference in hair styles, clothing styles and other faddish things. I recently saw a picture from about 100 years ago and I said to myself, I didn't know Matt Damon was a time traveler. ",
"Consider these things:\n\n1. mouth/dentistry. everything from sticking out, to assuredness of funkiness due to keeping wisdom teeth.\n\n2. aesthetic changes over time.\n\n3. very importantly - photography. Old photos were very long exposure (too long to smile!) this makes you look a little funky.\n\n4. posing aesthetics. If you've never seen yourself in a photo you probably don't know \"how to be\" when in front of a camera. We all do pretty specific things when a camera is pointed at us - those are learned / cultural.",
"Don't forget the importance of a changing gene pool. 100 years ago, immigration from the Mediterranean (Italians, Greeks) and Eastern Europe had barely begun. 60% of Americans had some German ancestry. And when immigrants arrived here, they tended to settle in particular regions, so you didn't have the genetic admixture that you got after WWII."
]
} | [] | [] | [
[],
[],
[],
[],
[],
[],
[],
[],
[]
] |
|
g39oir | how come us humans have to eat all these different food groups to get proper nutrients, like the food pyramid or other models, but herbivores like horses or cattle can just eat grass from the same fields their whole life and be fine? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/g39oir/eli5_how_come_us_humans_have_to_eat_all_these/ | {
"a_id": [
"fnq09xw",
"fnq2ad1",
"fnq3s3g"
],
"score": [
8,
15,
3
],
"text": [
"Other animals have evolved to get most, if not all, of what they need to survive from a single reliable food source - plant matter, for example.\n\nOne of humankind's biggest strengths is that we can survive if our main food source is lost, but we're not quite optimized, so it takes some tweaking to get the nutrients exactly right.",
"Because we're not herbivores and have not evolved (or have evolved out of having) a stomach capable of extracting all nutrients from grass.\n\nCows don't do much endurance-hunting, long-distance running or (one of our biggest energy uses) brain function. They spend most of their lives using their energy to digest their food and build their bodies. We don't. We use the cows already-grown bodies and just steal all their nutrition after their death.\n\nWe've either never eaten grass as our only diet, or have evolved away from eating grass because there was an advantage not to. Not every animal grows in the same environment, or makes the same evolutionary \"decisions\" and yet, they have been successful just as long.\n\nBut if you want quick, compact, nutritious food to fuel a high-energy lifestyle, and have chosen a lifestyle based on walking on two legs (unnecessarily energy-consuming) and endurance-hunting (chasing an animal like a cow day and night until it collapses from exhaustion and then you eat it), then you don't have (and don't want) the biological machinery to eat grass - you won't use it, it's comparatively inefficient, and it weighs a ton.\n\nCows, however, went for a sedate life, not being a predator (hence they become prey), utilising all their energy to extract the most from very-tough-to-digest grass, and turned it into muscle and fat in order to make them difficult to kill for most animals.\n\nHorses went for speed, shyness and strength. But they can't do it for very long. They are very dangerous in the wild, however, until we learned to tame them with tools and techniques that we created (outsmarting them by running them into a dead-end valley, etc. which isn't something you see an alligator do).\n\nDifferent evolutionary paths, branching off all over the place, and we happened to get the one that steals nutrients from other animals by eating their meat after hunting them using brains and endurance, rather than the ones that make all their nutrients but are literally unable to hunt (a cow can't hunt anything, and is as dumb as... well... a cow).",
"Humans are intelligent because we require that intelligence to enable us to get food from virtually any sources at any time and any location, which means that even in changing circumstances we can survive, unlike animals which require specific conditions to survive."
]
} | [] | [] | [
[],
[],
[]
] |
||
717t4n | how do noise cancelling shooters ears work? | I just bought a new pair of ears (long overdue) and I'm curious as to how they have a volume adjustment to hear outside the headphones at normal talking volume, but they can then cancel out louder gunshots. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/717t4n/eli5_how_do_noise_cancelling_shooters_ears_work/ | {
"a_id": [
"dn8qvyp"
],
"score": [
4
],
"text": [
"They work like regular ears to cancel out all sound. Then when you switch them on a microphone on the outside picks up ambient noise, processes it, and feeds it into the speakers in the ear cups. As long as that noise stays within a certain preset decibel limit it is allowed through. Any sound above the limit simply never makes it to the speakers.\n\nThere is actually a very slight delay for processing time, but it's on the order of a few milliseconds."
]
} | [] | [] | [
[]
] |
|
5qyhi5 | why aren't we incredibly thirsty after a long night's sleep? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5qyhi5/eli5_why_arent_we_incredibly_thirsty_after_a_long/ | {
"a_id": [
"dd33iv9"
],
"score": [
2
],
"text": [
"Your metabolism slows at night, and hopefully you aren't losing any fluids while asleep, although you do dehydrate some. I made a point to drink 18 oz or so of water first thing every morning, and it makes a noticeable difference."
]
} | [] | [] | [
[]
] |
||
53mf29 | what can i do to *genuinely* make a difference in climate change and help secure a sustainable future for planet earth? and can i somehow make a comfortable living from it? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/53mf29/eli5what_can_i_do_to_genuinely_make_a_difference/ | {
"a_id": [
"d7ucq3n",
"d7ucrje",
"d7ue25w"
],
"score": [
2,
4,
2
],
"text": [
"There's not really anything you can personally do to make a big difference. But a lot of individuals doing a small amount for the environment can equate to something big.\n\nAnything you could do to make a comfortable living from in this respect would involve a huge amount of capital. You could purchase 100 hectares of clear land and sell carbon offsets using a portion of the money earned to plant trees to offset a company's carbon footprint. You could even allow companies to drill into the land to deposit their pollutant gases. \nYou could develop a clean energy plant and sell the energy on the grid.\nThere's heaps you can do if you have the money.\n\nIf you don't have millions to invest into it there's not a whole lot you can do to make significant change without starting a movement but Al Gore already beat you to that one",
"Become a scientist or engineer and focus on developing renewable energy technologies. Find a job in an organization that is dedicated to decreasing the negative impact of climate change.",
"_URL_0_\n\nBy reading this page and making appropriate changes to your lifestyle (such as reducing meat to once or twice a week) - coincidentally this will also do wonders for your health.\n\n\"Livestock and their byproducts account for at least 32,000 million tons of carbon dioxide (CO2) per year, or 51% of all worldwide greenhouse gas emissions.\"\n\nRenewable energy technologies are literally a joke in comparison!\n"
]
} | [] | [] | [
[],
[],
[
"http://www.cowspiracy.com/facts/"
]
] |
||
8viwsr | why do us cities expand outward and not upward? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/8viwsr/eli5_why_do_us_cities_expand_outward_and_not/ | {
"a_id": [
"e1nnfzj",
"e1nniwx",
"e1nnjyb",
"e1nnqng",
"e1nnvcx",
"e1no7rc",
"e1npzhi",
"e1nqfig",
"e1nqsyd",
"e1nr9jr",
"e1nrtvf",
"e1nsced",
"e1nv71d",
"e1nw3s1",
"e1nxezg",
"e1nxmnf",
"e1ny48e",
"e1nyjnm",
"e1nyrx2",
"e1nz99o",
"e1nzd53",
"e1o02qe",
"e1o0ntt",
"e1o2ct9",
"e1o4bw5",
"e1o4mzb",
"e1o557j",
"e1o5oib",
"e1o5ypw",
"e1o6l75",
"e1o7eha",
"e1o7kmv",
"e1o7zgz",
"e1o9m83",
"e1off25",
"e1ok8n5",
"e1okak7",
"e1okhqs",
"e1olic2",
"e1oo4w8",
"e1oyu8k",
"e1pazr9",
"e1pb23n"
],
"score": [
6,
76,
8971,
53,
335,
18,
5,
776,
2,
13,
35,
634,
2,
12,
2,
148,
4,
2,
5,
117,
5,
2,
2,
7,
4,
19,
2,
5,
15,
2,
5,
2,
3,
5,
7,
2,
2,
3,
3,
14,
2,
2,
2
],
"text": [
"We have the space to spread out here. And it's far easier to build many shorter buildings than it is to build a few very tall ones. ",
"Many modern cities are increasingly growing upwards as well, but the simple physics of it is that even modest resources can create a ground level building. The higher you go, the more sophisticated the methods and the more intense the material requirements become. This means that outward is a more accessible proposition where your only major concerns are infrastructure, roads, power, water, etc. The actual buildings are much simpler. ",
"They expand upward when land is scarce or expensive, and they expand outward when the opposite is true.\n\nIn most cases, it is the later. The US is _huge_ and available land is not a problem that we have to deal with. Most major cities have more than enough surrounding land to expand on to at a fraction of the cost of a skyscraper.\n\nThere are a few exceptions, like New York where the value of being on Manhattan Island warrants the cost of upward expansion, but it just doesn't make financial sense for most cities.",
"Out is significantly easier. In order to expand up you pretty much need to tear up what's there and replace it all, including the roads and other infrastructure.\n\nThink of your average city block with just single family houses versus that same block with large apartment buildings. That's 100x or more the number of people that need power, water, and that'll be driving their cars. You need wider roads to accomodate, much larger water mains and sewage systems, and the surrounding businesses will even need to adapt to the much higher volume of customers.\n\nTo expand out all they need to do is continue with the same general building style. The odd road might need to be adapted to have more lanes, or a new road might have to be put in, but those are minor in comparison.",
"1. Land is much cheaper in much of the USA than in some other, more crowded countries.\n2. When you build upward, you may annoy your neighbors. When you build outward, you don't create this same effect.\n3. Often the builder doesn't have to pay much of the cost of roads, traffic jams, train lines, sewer systems, water delivery systems, and other costly infrastructure. The cost of the \"sprawl\" they create is not paid by them.",
"There is a move towards vertical space. There's something called \"air rights\" which is the value of the space above a building. The air above the roof is so valuable they want to capitalize on it.\n\nIn NYC, you have all these high-rises and then small 1 or 2 story structures. Developers see that as wasted space so they want to demolish smaller units and use that space for taller buildings. \n\nOn the other hand, a lot of colleges have city ordinances that prevent tall buildings (esp in small communities) with a smaller footprint and prefer longer ones that aren't so high.\n\n",
"Depends on the city... Chicago expands upward, New York expands upward.\n\nIn many cities, however, land is cheap and everybody has cars so density had been viewed as less necessary. There were also cultural aspects like whites wanting to flee minorities, the desire to have a patch of land, that caused people to move further our rather than build more densely in closer proximity to the city center.",
"I'd like to add that in addition to building out being easier and cheaper than up, some cities in the US have local ordinances forbidding buildings above a certain height. Boulder, CO is one such place, which restricts buildings to no taller than 55 feet.\n\nEDIT: Spelling",
"Money!\n\nAs so often the answer is: \"Money!\"\n\nIn much of the world it is much cheaper to expand a city outwards instead of building up withe skyscrapers.\n\nYou only see cities full of skyscrapers in places where room is scare and you either have to build up or hours away from where you want your space to be.\n\nThere are some exceptions in the form of vanity buildings like that giant hotel in Pyongyang, but mostly you only get skyscrapers were the cost of building them is made up for by the advantages of being in the place you build them.\n\nGiant sci-fi acrologies and massive cyberpunk versions of *Kowloon Walled City* are not a thing because they would be extremely expensive or unsafe to build.",
"It's a combination of zoning and land use restrictions (and space available). Same reason there are no skyscrapers on the coast of California. ",
"Given the choice, most people would prefer to buy their own land and have their own house. As an area becomes more and more packed, and property near downtown gets more and more scarce, people build upwards and live in condos/apartments.",
"The replies so far are on point. But let me tell you a little story of my neighborhood.\n\nI live in an European city with around 2 Mio people. Rent costs kinda exploded in the past 15 years and apartments are hard to find. People are quite upset about that. Furthermore in my neighborhood there was this old, ugly building. It was built in the 70s for a discount furniture store that closed in the 90s. There was a gym in until like 2002 and since then it's empty. Next to it is a small 60s house, the ugliest thing you've ever seen, also empty. So the city decided to buy the land and build affordable housing there. Good thing, right?\n\nHouses in the neighborhood are around 8 stories, the proposed house is about 10 stories, same as the building that is to be demolished. Additionally there's a slim tower on top of that at the corner, that's anoiter 5 stories. This should create a bunch of affordable apartments, the architects chose a very subtle approach that's neither overly ugly nor overly showy or noticeable. That architect didn't try to compensate their personal issues nor were they trying to set themselves a landmark.\n\nSo there was a neighborhood initative to prevent this building from being built because it's ugly (compared to an abandoned discount store building that has the charm of a rusting shipping container), because it takes away all the sun or just because it's new. Local newspapers picked up on this and discovered that the \"announced specs\" were off, the building is 10cm higher than the old one and their calculation from the door to the subway station was off about 2m. If you went to the article on the homepage of the newspaper or their Facebook page you could literally find dozens of people who were condemning any building with more than 3 stories and idealizing the suburbs and one-family-home as the only acceptable style of building. \n\nSo often enough the reason not to expand upwards (as they do in Asia quite often) is because of morons who complain because of boredom and change itself. I've seen several buildings and plans not making it to construction because of citizen protests. It's ridiculous and stupid and my sole goal in life is to never become one of those people.",
"Expanding upwards is expensive and so it is done only when land is scarce or the cost of buying it is more expensive. The US in general has lots of land so we build out in general. \n\nYou also have to have the right kind of land to build the extremely tall skyscrapers. If you cannot dig down deep enough to get to stable bedrock you cannot build that tall. So if the bedrock is too deep, or if it is something crumbly like shale or sandstone it is not good for building on. ",
"Real engineering did a great video on this very topic: \n\n\n[_URL_0_](_URL_1_)",
"Because outward is way, way cheaper.\n\nHalf a mile west is a few minutes in your car. Half a mile up is a multi-billion dollar construction project.\n\nAlso, there is more out than up. Up only has one direction to go, outwards has four.",
"There are a few reasons that this has and continues to happen in the United States:\n\n1. The value of land. The city of Phoenix, for example, has relatively cheap land compared to the city of New York. Thus, there is little motivation to construct tall buildings, which can cost much more (wood frame vs steel frame).\n\n2. City and State zoning ordinances. Some cities have extremely relaxed zoning laws, allowing builders and developers to do as they please. A great example of this is the city of Houston, where zoning laws have been almost non-existent. This is referred to as urban sprawl.\n\n3. Finally, and this is something I have not seen otherwise noted, a massive portion of the United States has been developed along side the automobile. This has allowed you to live 5 miles from the grocery store with no problem at all and you can see that trend with urban sprawl as a whole. This example makes a lot of sense when you apply it to older cities vs newer cities. Chicago and New York, for example, compared to San Diego and Seattle, which are sprawled geographically.\n\nEdit: changed my last sentence in response to u/fatherweebles\n",
"We, in the US, have a larger square footage to work with in comparison to cities in other countries. Take Romania for example. The apartment complexes have a lot of floors. The buildings have to move upward because there is not enough land to support the population. It’s a very small country by square mileage, as are many European countries. But they really don’t have much to work with when all of the real estate in the surrounding area is taken. Too many residents? Build it taller.\n\nI live in Texas, the state is enormous and the distance between two towns “out in the country” could be anywhere between 10 miles and 50 miles. You can travel for over twelve hours in a single direction and still be in the same state. The major roads seemingly last forever, and it is common for the speed limit to be 75 miles per hour, even on rural highways with two lanes per side. But the cities are also widely spread out. If you drive through the city in moderate traffic, it could take you nearly an hour to reach the opposite side, or longer. Dallas, Arlington, and Fort Worth are huge. Fort Worth is the 15th most populated US city as of last year, with Houston coming in at number 4, and Dallas at number 9. Fort Worth only has a handful of buildings over ten floors high. The tallest building is Burnett Plaza, which is 49 stories and under 600 ft tall. For size comparison, the Empire State Building in NYC is more than double that height. And this is nothing compared to places like Chicago, New York City, or Miami. They have much larger buildings and way more of them, and a large mass of land to build with. My point is, the US is a very big country and with a much smaller population in ratio to the available real estate. ",
"Land is cheaper than the buildings. \n\nWhen this is not the case, cities are generally expanded upward (see New York).\n\nIf it's cheaper to buy land and put a simple and cheap structure on it, that's going to happen more. \n\nIf the land is a significant investment, you're going to want to get as much use of every acre, so you build taller, even when the building gets exponentially more expensive.",
"Because people don't want to live like rabbits in blocks of flats. Most people prefer to have a house with lawn and garden and some living space.",
"Here’s the explanation for my Canadian city, which I’ve been told is one of the most sprawling cities in the country:\n\n\nThe fire code requires higher water main flow rates for higher density streets. Streets with only houses are built with the smallest possible water lines, for $$ reasons of course.\n\n\nSo if you want to tear down a block of houses and build a block of apartment buildings, you also have to tear up the road on that street and install larger water pipes...\n\n\n...but unless you picked juuuuust the right location, you’re going to discover that you have to also tear up and replace the next street over, because the water on your street comes from a street with a small water pipe...\n\n\n...and then you look at the next street over and the next street over and you realize it will cost 5 million dollars extra to build your block of apartments, just because of the fire code. And then you realize that you’d actually make more profit from buying empty land on the edge of town and building McMansions, so you do that instead.\n\n\n\nOf course, it’s cultural too. In my city unfortunately, living in apartments is seriously frowned upon. The majority of society hates them. If people liked apartments, they’d sell for so much money that the extra $5mil cost of tearing up roads wouldn’t even be a problem, because those apartments would sell sell sell!",
"most things like these go the way of the least resistence.\n\nif its cheaper/more profitable to build outside the city, people will do. if its more profitable/better to build in the city, people will build in the city",
"It's much cheaper to connect utilities to a new parcel of land and build a new 1- or 2-storey building than it is to demolish an existing building and build a taller one in its place.\n\nAlso keep in mind that a city isn't a single organization with a single mind; it's thousands and thousands and thousands of property owners with their own interests in mind.",
"I can speak for Philly:\n\nBasically philly has always had an unwritten “gentleman’s agreement” where no building could be built higher than the William penn statue on top of city hall. This was broken in the 80’s and now philly is building more upward than outward",
"Quality of life issues, for one:\n\n\n_URL_0_\n\n_URL_1_",
"To expand upward, you are putting more people per square foot. That's fine until you consider that people need to commute. That means, as you increase this density, you increase the commuter traffic. This forces the use of public transportation. But as places like Tokyo demonstrate, this has hard physical limitations. Once you reach the carrying capacity for your public transportation system, further growth within that immediate area is impossible, no matter what.\n\nOutward growth does not have (exactly) this problem, so long as you add more roads, and scale the residential and business areas somewhat evenly.",
"Cars. Cities on the east coast were built before the car, so they are more dense and walkable. Cities built after the car could be further away. Look up suburban sprawl. ",
"It’s less disruptive to add a new building where there’s never been one before than to demolish an existing building so you can build a higher one. \n\nTurning an 8 story building into a 40 story building takes many months and lots of money. Whoever owns that 8 story building would often prefer to just keep collecting rent from their tenants and leave things as they are. Going a year without collecting rent and then spending millions on a new skyscraper might be a big move they just can’t afford. The owner of that 8 story building is much more concerned with their own pocketbook than with any grand plan for the city’s development.",
"Charleston, South Carolina did it because they have a law where no building is allowed to be higher than the church with the tallest steeples. Not even the parking garages. Since Charleston is on a peninsula, it gets to deal with not only massive flooding that increases each year, but also lack of available parking without the benefit of being New York. Religion is the reason why, in Charleston.\n\nLas Vegas did it because during the housing market crashes they were selling land and making empty housing developments, so that they could continue to take loans from the bank, etc, even going so far as to pay actors to act as \"cool neighbors\" when people came to open house days. Greed is the reason why, in Vegas.",
"in addition to what others are saying, Americans also want to own homes more than people in other countries do. its part of the American Dream and many people couldnt fathom living in apartments their whole lives. That calls for outward expansion and creates suburbs",
"The U.S. is pretty car reliant and suburbs are a staple of American society, so when everyone wants low rise subrurbs it turns into urban sprawl. The U.S. has a ton of land and most cities are situated on flat land so it's cheap, easy, and attractive to build outwards. Some cities don't have those opportunities for a few reasons, most often it's geography though for the big ones like NYC, San Francisco and Miami.",
"Aside from the differences in land value and vertical construction costs that others have mentioned, in many cases, local governments subsidize the roads and parking areas. This means it is considerably cheaper to build out instead of up. This contributes to urban sprawl; it's inherently unsustainable also, so it eventually leads to urban decay. See _URL_0_",
"Canada is the same, we have a ton of land to expand on, why pay more for a skyscraper?",
"Cars. Before cars, people had to remain within walking distance for all their needs. So to keep people close but still have a growing population, you just build up. More modern cities however have been erected after the prevelance of automobiles, making it possible for suburban living.",
"Chicago and New York both have more skyscrapers than the entire eu combined. Why are you asking about the us?",
"San Francisco has nowhere left to build but upward, and they refuse to do that. Rents then go up to the highest in the nation, even more than Manhattan. Then you have cities like Seattle that refuse to either expand upward or outward. The result is you then you get an out-of-control homeless problem.",
"One reason maybe because it's easier to buy vacant land then it is to negotiate a contract for owned land that already has a short building on it.",
"Shortest answer: because most of them have the space to move outward and it's much cheaper.\n\nThe population density in the US is pretty low so unless there's geographical features preventing it (like say NYC being on islands), it's much cheaper for most cities to just extend outward and push the suburbs farther and farther out. . .",
"Living in a large metro area in the US, I wish we could build upward and have all the space in between be efficient highway designs and free parking. That would be the dream",
"A little late, but I'll add my explanation coming from the perspective of a traffic engineer.\n\nWhile cheap abundant land is a part of it. The bigger factor is the post ww2 decision that success meant owning your own home and owning a car. State and federal governments supported this by building lots of highways between cities and through undeveloped land (and through minority neiborhoods) this expansion of highways also led to the decline of American passenger rail. \n\nThen the suburbs were built, the federal government also helped fund these new towns by subsiding mortgages (but not subsiding Apartments except for the very poor). This meant that it often was more desirable and cheaper to move out of the inner city where you took the bus, streetcar or subway to work and move to a place where you had a plot of land and would drive to work.\n\nThis started a cycle where people would move out farther and farther from the city, with a longer and longer commute and where they could afford those cheaper plots of land. This cycle is called \"drive till you qualify\". It also means that the metro areas for mid sized American cities can be the size of European or Asian cities with 5-10 times the population.",
"I see a lot of talk about regulations and stuff.\n\nOne thing missing is cultural. In America, the idea of owning your own land is huge. It's a sign of success. You go out, get your career, get a house, a dog, a wife, a white picket fence, two cars and two and a half kids on a tree lined street with a side drive. Then you build a man cave in the basement to get away from it all, and build a deck to invite people over to watch you singe meat so they'll all be suitable impressed with your perfect life. Then after the party is over you go back to your man cave and cry over your credit card debt with a case of cheep beers before going upstairs to your already asleep wife.\n\nWait. What was the question? Oh yeah. It's also because owning a home is culturally important in the USA.",
"There is a longstanding and powerful desire to own a single family home and a plot of land to call your own, where you can maybe have a pool for the kids and a garden to tend. Not possible in a 30 storey condo tower. \n\nAlso, once that single family scenario is established, there is often significant resistance to any development more dense than that in that neighbourhood.",
"Depends on the ground beneath. The ground beneath Seattle is hard and strong, good for tall buildings. The ground beneath most of Tacoma is soft and weak, which will make buildings sink and collapse. There's strong earth way below the weak earth, but it cost too much to run supports down to it to hold up a building.",
"Upward growth requires a group of people who agree to build one huge thing.\n\nOutward growth only requires many people who build many smaller things. "
]
} | [] | [] | [
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[
"https://youtu.be/3qLsPHz\\_Hr8",
"https://youtu.be/3qLsPHz_Hr8"
],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[
"https://apps.bostonglobe.com/business/graphics/2018/04/tallest-buildings/",
"https://www.citylab.com/equity/2012/06/birth-zoning-codes-history/2275/"
],
[],
[],
[],
[],
[],
[],
[
"https://www.strongtowns.org/the-growth-ponzi-scheme/"
],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[]
] |
||
b1l3i9 | why would a helicopter have no problem carrying thousands of pounds at a low altitude, but cannot carry the same weight at a significantly higher altitude? | Watching Triple Frontier and this is a significant plot point. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/b1l3i9/eli5_why_would_a_helicopter_have_no_problem/ | {
"a_id": [
"eimfij1",
"eimmmf7",
"einaw9s"
],
"score": [
64,
19,
3
],
"text": [
"Air is significantly thinner at high altitude. So a helicopter cannot produce enough lift without anything to resist it.",
"There is less air for the blades to push on. Same reason airplanes can't just fly into space. \n\nI just watched it last night and was pleased that the aviation part wasn't 100% stupid and unrealistic.\n\nThe gearbox probably wouldn't fail; it would probably just not make it over.\n\nBut the part about the weight being too much for the altitude *and the pilot knowing that ahead of time and telling everyone* was totally right.",
"When people say that 'the air is thinner' at higher altitude, think of it like branches on a tree. Sure, the nice thick branches near the base can easily hold a person up! You could probably jump on them or fit two or three people on a single branch.\n\nBut the higher you go, the thinner the branches, and the air, get. Some of them can support you, some of them can support someone smaller than you, but eventually they're too thin to carry as much, or any sizable weight. \n\nEdit: It was brought up that in the scene that raised this question, the problem was maintaining altitude. The example still holds, since a thin branch might work as a handhold, or might even hold weight for a little while, the strain would eventually cause it to break and, at best, for you to slip back down to better footing."
]
} | [] | [] | [
[],
[],
[]
] |
|
nih8i | the difference between science and art degrees in the same field, and the difference between science and applied science. | For example, most college have both a BS Psychology and a BA Psychology program, with different course requirements. What is the difference?
Similarly, what is the difference in a ASBA (Assoc Science Business Admin) and an AASBA (Assoc Applied ") | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/nih8i/the_difference_between_science_and_art_degrees_in/ | {
"a_id": [
"c39cpp2",
"c39cpp2"
],
"score": [
2,
2
],
"text": [
"I can only speak to my expiriance as a BA in Biology major.\n\nBut at my school getting a BS vs a BA in a 'science' field meant taking more difficult classes in your major and allowed less 'elective' courses outside. The specific difference was that to get a BS instead of my BA, I would have needed 9 more credits in master's level courses and I think a thesis (but I can't remember).\n\nApplied science is the study of science and it's uses in the commercial, or 'real world.' Whereas 'science' is mainly theoretical in nature and academic rather than commercial. \n\ntl,dr: A BS requires more 'hard science' classes in the major than a BA; Science=Why? Applied Science=Profit from why?",
"I can only speak to my expiriance as a BA in Biology major.\n\nBut at my school getting a BS vs a BA in a 'science' field meant taking more difficult classes in your major and allowed less 'elective' courses outside. The specific difference was that to get a BS instead of my BA, I would have needed 9 more credits in master's level courses and I think a thesis (but I can't remember).\n\nApplied science is the study of science and it's uses in the commercial, or 'real world.' Whereas 'science' is mainly theoretical in nature and academic rather than commercial. \n\ntl,dr: A BS requires more 'hard science' classes in the major than a BA; Science=Why? Applied Science=Profit from why?"
]
} | [] | [] | [
[],
[]
] |
|
6cfm4f | biting your mouth | So you know how you're eating some good food and then ya bite the inside of your mouth and it really hurts? Then you do it again a few hours/days later in exactly in the same spot. why is that? Help. I feel like I've ravaged the inside of my cheek at this point | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6cfm4f/eli5_biting_your_mouth/ | {
"a_id": [
"dhubcwu"
],
"score": [
7
],
"text": [
"When you first bite your cheek it gets inflamed. It swells a bit and so grows bigger. This makes it easier for you to bite it a second and third chance."
]
} | [] | [] | [
[]
] |
|
d3ysx6 | why are knee extensions bad for your ligaments? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/d3ysx6/eli5_why_are_knee_extensions_bad_for_your/ | {
"a_id": [
"f060bm1"
],
"score": [
2
],
"text": [
"Leg extensions put a lot of pressure on your knees, especially if you have a lot of weight placed on them. They also put tension on your ACL and overall isn’t the best exercise to use when training your quads because the risk of injury is too high compared to the gain"
]
} | [] | [] | [
[]
] |
||
1xfth6 | what is the knot in my stomach when i'm nervous/scared? why is it there? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1xfth6/what_is_the_knot_in_my_stomach_when_im/ | {
"a_id": [
"cfazkn4",
"cfazmuf",
"cfb0lmq",
"cfb0y5d",
"cfb1p1l"
],
"score": [
3,
71,
2,
7,
3
],
"text": [
"Here in the UK it's called [\"Collywobbles\".](_URL_0_) If that's not the most adorable name for acute nervousness, I don't know what is. ",
"During an episode of anxiety, lots of stress related hormones called catecholamines are released, and the body's \"fight or flight\" mechanisms are ramped up through the sympathetic nervous system. \n\nNormally, this fight or flight sympathetic system is balanced by the rest and digest parasympathetic system - both are constantly balancing out the automatic processes in your body such as heart rate, contractions and relaxations in your digestive tract, etc. \n\nSpecifically in the digestive tract, your \"rest and digest\" system of nerves allows for digestive secretions, contractions of the muscles lining your digestive walls, and other mechanisms which allow for your food to be mixed up, absorbed, digested, and moved along. \n\nHowever, when fight or flight takes over, digestion becomes less of a priority, and stress hormones and sympathetic nerves suppress these rest and digest functions. Less secretions, less digestion, less contractions and movement. Because this comes on so quickly, it can cause a nauseous sensation that can feel like knots in your stomach. \n\nAlso stress hormones can cause for more acid production in your stomach which can cause reflux. And your abdominal muscles may be tightening up due to the increased muscle contraction that comes during fight or flight.",
"Your gut actually has a *lot* of nerve endings in it, often earning it the moniker the \"second brain\". As one poster mentioned, during times of stress, a lot of neurophysical changes happen. Catecholamines (adrenaline & noradrenaline) are pumped out, cortisol and other stress hormones are released, and changes in bloodflow cause sudden shifts in the peristaltic (movement) and chemical behavior of the bowels.",
"What a coincidence, this just came out...\n\n_URL_0_",
"My husband almost died last month, he spent 11 days in the ICU and another six in a regular room. Until he regained consciousness and we were certain he would survive, I walked around with that terrible feeling 24/7. It felt like a constant fist in my gut. I could barely eat or concentrate on anything. Just awful."
]
} | [] | [] | [
[
"http://www.oxforddictionaries.com/definition/english/collywobbles"
],
[],
[],
[
"https://www.youtube.com/watch?v=hew3z2FIbME"
],
[]
] |
||
50y63u | where did the idea of zombies came from? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/50y63u/eli5_where_did_the_idea_of_zombies_came_from/ | {
"a_id": [
"d77ug7p",
"d77usyz",
"d77vb7j"
],
"score": [
2,
4,
4
],
"text": [
"The modern idea of a zombie can be considered to be a mix of inspirations from various authors and myths. However, for the most succinct and early example of what we call zombies, you probably want Haitian myths about voodoo magic that dangerous priests practiced to resurrect the dead to use as slaves. ",
"It's not really known where exactly belief in zombies come from. Our word comes from Haitian French, where zombies were believed to be corpses re-animated by witchcraft of some sort; in turn, the Haitians apparently got that concept from West Africa.\n\nIt has been claimed that unscrupulous people could make a drug that effectively put people into a sort of zombie state, in order to put them to work as slaves: there's no evidence of that at all, though. Another suggestion is that it came from observing people with what we today would consider psychological conditions with symptoms like catanonia, mixed in with everybody's desire to see their deceased loved ones again -- the hope that they might one day \"come back from the dead\".\n\nPossibly the reason this belief took off in Haiti was because it chimed in with their experiences of slavery. In Haitian folklore, corpses could be re-animated by magic to become, basically, slaves, doing whatever you asked them to do. You could, though, save a zombie from their enslavement by, for example, feeding them with salt.\n\nIn fact, there were two types of zombie: the body without a soul (which evolved into what we today think of as a zombie), and the soul without a body (the \"zombie astral\", which could be trapped in a bottle and sold to people as good-luck charms -- a sort of snake-oil scam, essentially).",
"I believe that a lot of the Haitian zombie myth comes from the horrible working conditions on sugar plantations during the 17th and 18th centuries. These people were slaves, ripped from their homeland and set to work with unfamiliar and inadequate food. They had no protection from the sun, and even had much of their religions stripped away.\n\nThese people were literally worked to death, with a lifespan in slavery of about two years. When things are this bad, death looks good. Enter the horror story of the time. \n\n\"After you are dead, your body can be raised by sorcerers, who can force your undead body to work forever. Even death will give you no rest.\" It was the worst thing these people could imagine, that they would work on and have no rest after death.\n\nThis is the way it stayed, occasionally tricked out by stories of a man who had raised the body of a woman he loved so he could rape her eternally. \n\nEnter George Romero, who wanted to make an alien invasion movie in 1968. He didn't have the money for alien makeup, so he decided to use zombies. \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n"
]
} | [] | [] | [
[],
[],
[]
] |
||
9yogd1 | what are magnets made of? | I mean, what is the base material to produce a magnet? How are they manufactured?
Now that I think about it, there must be lots of constraints producing strong magnets.
Thanks for the replies! | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/9yogd1/eli5_what_are_magnets_made_of/ | {
"a_id": [
"ea2y9q8"
],
"score": [
5
],
"text": [
"Magnetism is created by the movement of electricity, typically electrons. Electrons spin, and orbit the nucleus of an atom (so they move), and they ARE electricity, so each electron is a tiny magnet.\n\nMost atoms have enough electrons spinning in opposition that the magnetic effects cancel out. Some atoms (iron, cobalt, nickel), the electrons spin the same way, so overall the atom itself is a magnet.\n\nSo, going from individual atoms to quantities of a substance that we handle in day-to-day activities, there are about 10^20 - 10^23 atoms per gram or ounce of material, so the chance of them lining up all pointing in the same direction is very small. \n\nHowever, if you heat up the material to where it gets melty and the atoms get \"loose\", and then apply a magnet in the vicinity, the individual atoms will line up with the magnet, because of the magnetic forces. Then you cool the material to cold solid, and trap the atoms all lined up, so the individual atomic magnets all add up together to form a hand-sized magnet.\n\n[National Geographic Article](_URL_0_)."
]
} | [] | [] | [
[
"https://www.nationalgeographic.org/encyclopedia/magnetism/"
]
] |
|
2ni6fq | why does a wet trampoline feel like it makes you jump higher? does it actually do that? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2ni6fq/eli5_why_does_a_wet_trampoline_feel_like_it_makes/ | {
"a_id": [
"cmdsxww",
"cmdutuc",
"cme4v6p"
],
"score": [
3,
3,
2
],
"text": [
"I recon it doesn't...the only think I can think of is if it is cold water, the trampoline fabric/springs might get tighter as the materials contract.",
"that sounds like a euphemism from a galaxy far away. \n",
"I always thought that the water acted as a lubricant, enabling the fabric to move more freely. Therefore, letting you jump higher."
]
} | [] | [] | [
[],
[],
[]
] |
||
evy0n3 | how does all the digging of tunnels and construction of tall heavy buildings not lead to land cracking and breaking apart? | Always wondered that especially for dense cities like Singapore, Tokyo and New York, how do engineers continue to dig deeper and build higher without risking the land cracking apart like the ice age squirrel's nut cracking the glacier, and having all the infrastructure just sink into the ocean? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/evy0n3/eli5_how_does_all_the_digging_of_tunnels_and/ | {
"a_id": [
"ffyp8z3",
"ffyxond"
],
"score": [
3,
6
],
"text": [
"The ground is really strong. Also, there are engineers who basically only deal with figuring out if the ground can support the loads of buildings and other structures.\n\n_URL_0_",
"Tunnels and foundations aren't dug haphazardly and right underneath the surface. Engineers and geologists study the ground to determine where to dig tunnels and foundations. What they're looking for is bedrock. Bedrock is the extremely hard, sturdy rock that lies under softer material like dirt, mud, clay, or sand. Bedrock is extremely strong. If you build your tunnels and foundations down to bedrock, the weight of of everything on top is distributed over a huge area, and can easily support the weight of anything on top."
]
} | [] | [] | [
[
"https://en.m.wikipedia.org/wiki/Geotechnical_engineering"
],
[]
] |
|
28mjp4 | what are aleph 2, 3, .... n ? why is there an aleph number greater than aleph-1? | I read this reddit explanation of aleph-0 and aleph-1 (_URL_0_) and understand those concepts. However, why are there aleph-2, 3, ... and so on? Can someone explain what these extra aleph numbers mean, and why there is an aleph number greater than aleph-1? Thanks | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/28mjp4/eli5_what_are_aleph_2_3_n_why_is_there_an_aleph/ | {
"a_id": [
"cicc85l",
"ciccnqa",
"cicczhs"
],
"score": [
2,
2,
4
],
"text": [
"Basically, to define an aleph number, you take all the aleph numbers that came before it. Then you count up how many ways you can put that many objects in order, and *that* number is your new aleph number. Since there are many more ways to order a collection than there are elements in that collection, each aleph number is bigger than the previous one (in some sense, *much* bigger).\n\nThere's no limit, in principle, to how many times you could repeat this process, so there are infinitely many aleph numbers.",
"At some point, you'll need to stop looking for superficial answers. You're getting to some pretty out there, abstract stuff - beyond what pretty much anyone that's not a math major in college gets to. If you really want to keep pursuing it, it might be time to engage in a proper study of mathematics.",
"Consider sequences of length 3 composed of zeroes and ones. There are 8 of them: 000, 001, 010, 011, 100, 101, 110, 111.\n\nI give you three of them (look only at rows):\n\n 010\n 100\n 011\n\nWhat are sequences that are not in this array? There are 5 of them: 000, 001, 101, 110, 111.\n\nHere's a way to find one of those 5 sequences in a magic manner. Take a look at the diagonal of this square - it is 001. Flip all bits to get 110. Now, this sequence is guaranteed not to be in the array, no matter what the numbers originally were. It cannot be the first sequence, because they differ on the first place. It cannot be the second one, because they differ on the second place and so on. Even if the array was\n\n 0**\n *0*\n **1\n\nwhere * is a \"wild card\", the sequence 110 could not be in any of its rows.\n\nWhy is this magic? Because it works not only with length 3, or length 10, but even with infinite length.\n\nIf I define a square that has infinitely many rows and columns\n\n 00001...\n 11011...\n 01010...\n 11111...\n 00111...\n ........\n ........\n ........\n\n\nthen the infinite sequence 10100... is guaranteed not to be as one of its rows.\n\nEven more, this argument can be carried out with larger sets. Instead of an infinite sequence (which is a function N - > {0,1}) you take a function X - > {0,1} where X is any infinite set.\n\nWhat it shows is that for every set X, the set of 0-1 sequences indexed by X cannot be put in a 1-1 correspondence with X. So if X is naturals, then the set of 0-1 sequences indexed by naturals (call it Y) is set-theoretically larger. But then there exists a set Z which is to Y as Y to X. You can repeat that process to get a sequence of sets B0 = X, B1 = Y, B2 = Z, ... which are all infinite and progressively larger.\n\nI called them B because the sequence of such cardinals is called beth numbers: beth-zero, beth-one and so on.\n\nYou can wonder if there a set which is larger than B0 but smaller than B1. Turns out, the axioms of the set theory neither force nor rule out this possibility. However, if you assume an additional axiom that rules out this situation, then the sequence of beth numbers becomes the same as aleph numbers. (In general, aleph numbers are all infinite cardinals, while beth numbers are those which can be created from the above construction).\n\nIf you think it's this is the end, you're gravely mistaken. Take a set which is the union of B1, B2, B3, ... This set has cardinality larger than aleph-one, aleph-two and so on. Its cardinality is called aleph-omega. Next, you can take the 0-1 sequences of that, and get aleph-(omega+1), and aleph-(omega+2), and aleph-(omega+3), and aleph-(omega+omega) and aleph-(omega+omega+1), and aleph-(omega\\*omega), and aleph-(omega\\*omega\\*omega), and aleph-(omega^(omega)). You seem to be getting dizzy so I'll stop here."
]
} | [] | [
"http://www.reddit.com/r/explainlikeimfive/comments/x86wt/aleph_numberswhaaat/"
] | [
[],
[],
[]
] |
|
20golm | why does it seem like we don't hear a lot about north africa in regard to wwii? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/20golm/eli5_why_does_it_seem_like_we_dont_hear_a_lot/ | {
"a_id": [
"cg320lv",
"cg326dg"
],
"score": [
2,
6
],
"text": [
"Because America was barely involved in Africa ",
"The short answer is because the North African Campaign was a sideshow. It served no real tactical purpose for the Axis and it was theirs to lose, really. \n\nYou mostly hear about the North African Campaign because of Rommel's Afrika Korps and Montgomery's Desert Rats. Rommel fought a chivalrous war and is generally considered one of the greatest generals of the Third Reich. \n\nOf course, since I'm assuming you're American, it's also because America really didn't play a role in the North African campaign. It was mostly the British Eighth Army's doing."
]
} | [] | [] | [
[],
[]
] |
||
3excb8 | why is sugar bad in soda/energy drinks but not juice? | Red Bull has 39g of sugar and that's been labeled bad. A small Naked juice has 57g but no one says Naked juice is unhealthy. What's the difference? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3excb8/eli5_why_is_sugar_bad_in_sodaenergy_drinks_but/ | {
"a_id": [
"ctj8smm",
"ctj8snq",
"ctj8vmk",
"ctj8xsx",
"ctjh3fc"
],
"score": [
19,
4,
2,
2,
2
],
"text": [
"Nothing. Sugar in juice is just as unhealthy as sugar in soda. \n\nPeople just don't *think* that there's that much sugar in juice.",
"The sugar is bad in either one. Red Bull has very little nutritional value otherwise, which is why it seems unhealthier. The juice has some vitamins, at least.\n\nBut it's true that juice (in general) has a lot of sugar and people mistakenly view it as being more healthy than it really is. We tend associate juice with fresh fruit, even though it has way more sugar than fresh fruit. The juice companies tout their high vitamin-C levels and don't mention the high sugar content. It's marketing.",
"Lots of sugar is unhealthy in any diet. The difference is that fruit juices have nutrients that make them somewhat more worth drinking, while sodas and energy drinks pretty much only provide sugar. There's no redeeming health value to an energy drink (although the energy can be nice), while fruit juice will at least put some vitamin C into you.\n\nA diet with lots of fruit juice can be nearly as bad for you as a diet with lots of Red Bull. Like any food, moderation is the key.",
"People tend to differentiate between sugar and ADDED sugar as in the sugars present in the juice are the sugars naturally present in the fruit it is made of where redbull just pours kilograms of sugar into their vats. The reality is there isnt a nutritional difference, a ton of sugar from either source is bad but juice tends to have a few redeeming qualities like vitamins and minerals",
"The question some may have is where does the sugar come from and how does your body handle it. There are all sorts of sugars, Glucose (simplest), Fructose (Fruit Sugar) and Sucrose (table sugar) and additionally Lactose (milk sugar). Glucose is immediately used and is responsible for the \"sugar rush\". Fructose needs to be broken down in the liver to be used. Sucrose needs a further enzyme to be broken down into one Glucose and one Fructose giving you a sugar rush as well as a later bit of energy. Lactose needs another enzyme to break down. If you have liver problems you might have problems with Fructose or Glucose. If your lactose intolerant, lactose is a problem. If you're diabetic then all sugar has a problem for you. The latest controversy is that people feel High Fructose Corn Syrup which is cheap and used in many drinks is bad, though I don't think there is any conclusive study to say that. It's not much different from Table sugar. So some juices are thought to be healthy because they don't add HFCS or other sugar but there is no substance to such a claims. \n\nI don't think any one really knows BUT high intake of sugar is not considered good and has been linked to diabetes and obesity among other health issues. \n\nA teaspoon of sugar is 4 g. Therefore your Red Bull is 10 teaspoons while the naked juice is a whooping 14 1/4teaspoons. I drink tea and coffee with 1 teaspoon, 2 max. 10? 14? That's too much if you think about it (ever eat 14 tspoons of sugar by itself?).\n\nDisclaimer: I'm not a doctor nor do I play one on TV."
]
} | [] | [] | [
[],
[],
[],
[],
[]
] |
|
2k35pb | how do movies or television shows recreate the abandoned city look or zombies invaded town look, obviously they have large budgets but how do they go about it? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2k35pb/eli5_how_do_movies_or_television_shows_recreate/ | {
"a_id": [
"clhgboc",
"clhpbwd"
],
"score": [
6,
2
],
"text": [
"A lot of the time, they close down the streets for a short time. 28 days later got London to look deserted by shooting before the sun came up and closing the streets off. For the larger landscape views, they just edit with computers. ",
"Digital compositing has reached a point where it is frequently unnoticable. \n\nWhilst it does tend to be noticeable in contexts that are unusual (ie. the abandoned city - you aren't used to seeing it, so you pay a lot more attention to the scene) it is virtually unnoticeable in everyday contexts. Quite a bit of 'location' shooting is done on studio lots now, and if you look at something like Game of Thrones there's a ton of digital set extension that is more than convincing (because even in Europe there aren't that many giant city-castles).\n\n[Examples](_URL_0_)"
]
} | [] | [] | [
[],
[
"http://youtu.be/4ypn0KI43hE"
]
] |
||
62804t | why do large telecom, cable, and internet providers have such a culture of poor customer service? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/62804t/eli5_why_do_large_telecom_cable_and_internet/ | {
"a_id": [
"dfkgfwv",
"dfkicl0",
"dfkk47o",
"dfkk58n",
"dfkl6fs",
"dfkmsao",
"dfkract"
],
"score": [
15,
5,
2,
2,
3,
2,
2
],
"text": [
"In the most simple terms, customer services does not make the company any money. In fact it COSTS them money, so they try to find ways to reduce that cost the most they are able. \nThey only want to keep it so that the cost of lost customer revenue is less than the cost of operating the service. If lost customer revenue is more than service, they will pay to get better service, if less, they will skimp on the service budget until it reaches an equilibrium.",
"Usually, its the cost of customer acquisition vs cost of customer retention.\n\nYou examples are companies that have a high cost of customer acquisition and a low cost of customer retention. This means, it's really expensive to get you to be a customer, but once you are a customer, it doesn't cost that much to keep you.\n\nThese are mostly subscription services, where there is a lot of inconvenience involved in switching to a competitor (if there is a competitor). This means you will accept a heap of abuse before you take your business elsewhere (if you even have a choice). So, they will save money where they can (customer service) and spend money where they must (get new customers).\n\nOn the other hand, services, like a carpet cleaning service find it hard to retain customers, so giving good service becomes a reason you stay. They spend money on customer retention and spend money on customer acquisition and they can't really afford to cut costs on either. In these cases, the place they save money is the cost or providing the service in ways that aren't detectable by the customer.",
"Well, most of the time they know you don't have a choice. \n\nIf you want high speed internet in my area, Comcast is your only option. It wouldn't matter if their customer service consisted of coming to your house every day and punching you in the face, if you need internet, you have to pay Comcast. \n\nEven if you do live in an area with multiple providers, it feels like they all work together to provide a similarly shitty experience so that one of them won't have an advantage over the other, just like they do with their prices. \n\nWelcome to the oligopoly.",
"I would say a big reason is because they mostly operate as a monopoly. In lots of areas you don't really have a choice of phone or internet, or if you do it's 2, maybe 3 companies. Internet is basically a requirement to live these days, phone and TV were historically like that. So have these services that a large majority of people will always buy. When companies don't have any real competition they don't really have to try and keep their customers, because they don't really have anywhere else to go. So, they just simply don't HAVE to care that much to still be hugely successful.",
"Because the don't NEED to treat you well - generally, telecom companies have regional monopolies so they don't really risk losing you as a customer. All you really are is an account that sends monthly payments to them. This might change with new players such as Google entering the market dominated by the major Telcos, and providing new competition.\n\nAdditionally, there is no real separation between customer service and sales. CSRs are expected to upsell or at the very least retain your business (and can lose out on compensation for not doing so), which can come across as pushy and can take away from the caring and service-oriented experience a customer might expect.",
"I work for a small ISP(less than 15k subs) company; we have a great rapport with our customers because we're small enough to miss individuals if they disconnect services compared to Comcast with 50,000,000 subscribers. If we increase prices or provide shitty service; we could lose a sizable amount of business. ",
"Many moons ago I worked in the customer service department for companies like this. Part of the reason the customer service is so poor is because the job is awful. It just is. You sit connected to a phone for 8+ hours a day staring at a computer screen listening to person after person call and take their frustration over the way MASSIVE CORPORATION does something out at YOU. Like I'm the guy that jacked up your rates, or cancelled your service 'cause you're behind in payments. \n\nUsually I talked to well over a hundred people a day, sometimes hundreds a day. Almost all of them pissed off, and a tiny fraction who are reasonable and understanding. Imagine talking to your crazy uncle/aunt/in-law who hates your politics and lifestyle. Nothing you say can make them understand where you're coming from or why you're not going to burn in hell. Now do that a few hundred times a day. \n\nTalking to people in general is exhausting. I'm willing to bet that unless you are a teacher, restaurant FOH worker, or call center worker, you probably talk to less than 20 people a day. Probably 5 of those are more substantive than \"Hey Steve, see the Gonzaga game?\" \n\nIts a job that sucks your soul. \n\nTip from my experience - be nice to call center people. They know they have shitty jobs. If you're that one customer who is patient, reasonable, and polite out of 200 who rage at me on a particular day, guess who is getting hooked the fuck up in any way I can?\n\nIn general, be nice to service people. I never stay at 'nice' hotels, but a situation warranted it last week. Talking to the valet guy over the course of a couple days and treating him like an actual human being resulted in free pizzas, hookups for cheaper transportation, tips on better/cheaper food than the overpriced tourist shit. "
]
} | [] | [] | [
[],
[],
[],
[],
[],
[],
[]
] |
||
70jxi7 | how do tv shows like forensic files find such perfect look-alikes to reenact scenes? | [deleted] | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/70jxi7/eli5_how_do_tv_shows_like_forensic_files_find/ | {
"a_id": [
"dn3pz2t"
],
"score": [
3
],
"text": [
"The industry company called Central Casting keeps a database of over 100,000 actors and actresses seeking work. They can query this database on a wide range of attributes including appearance, so they can quickly find someone close. Hollywood make-up does the rest."
]
} | [] | [] | [
[]
] |
|
46y686 | why is seafood so much more expensive than land based meat? | Seems like land based animals would cost more because you have to had the land to raise them, feed them, veterinarian care, etc. With Seafood all of that is done for you, you just have to go catch it and cook it. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/46y686/eli5_why_is_seafood_so_much_more_expensive_than/ | {
"a_id": [
"d08pa3b",
"d097y6f"
],
"score": [
9,
2
],
"text": [
"Because it can only be collected from the sea.\n\nIf you live in a coastal city seafood is often very cheap, but if you live inland it has to be shipped to you, and it has to be kept from spoiling. That is expensive. ",
"Pricing and perceptions change over time. In other times in history, fish was considered a poor man's food compared to meat. \n\nIn current times, the fact that all \"regular\" meats are farmed makes it less expensive. Farmed animals need more care etc. as you state, but it also is much more dependable and there is an economy of scale involved that makes it much more akin to mass production. \n\nCompare this to game. It needs to be hunting season and individual specimens must be hunted, shot and processed. This is a much more labor intensive way in terms of the ratio of person to meat production. Hunting depends on more variables that are not under control by humans. \n\nFishing, for most species of fish, is much more comparable to hunting. There are only a few types of fish that are suitable to being farmed commercially, most fish is actually being caught at sea. As humans, we've actually become really good at fishing for the most popular types of fish, which has resulted in many popular species becoming (arguably) threatened species. Which of course, makes those fish even more expensive. \n\nAs a last thing, sometimes there will be some form of vested interest in maintaining a certain amount of exclusivity to some foods, which may or may not relate to the actual cost or rarity of the product itself. \n"
]
} | [] | [] | [
[],
[]
] |
|
bjnhg9 | why does pain feel more painful when you arent prepared for it? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/bjnhg9/eli5_why_does_pain_feel_more_painful_when_you/ | {
"a_id": [
"em9m1bh"
],
"score": [
2
],
"text": [
"The element of surprise! Your body can unconsciously prepare for certain things. For instance: if you drink coffee everyday, at 8am, after a while your body begins to prepare for it by producing the \"antidote\" to caffeine. Very similar to how environmental cues can initiate relapse in drug addiction. So when you know you'll be slapped, your body can release endorphins, or any other endogenous analgesia."
]
} | [] | [] | [
[]
] |
||
1mxttv | why do schools and colleges spend so much money on administration, instead of teachers, construction, lower tuition, etc.? | Partially inspired by [this thread.](_URL_0_) | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1mxttv/eli5_why_do_schools_and_colleges_spend_so_much/ | {
"a_id": [
"ccdmczw",
"ccdmgpc",
"ccdr6zd"
],
"score": [
4,
3,
3
],
"text": [
"Depends on the school. But generally, a _URL_0_ a self-contained community, and so it has to be more than just teachers. It has to have dining facilities, police, tutors, IT, roads, all that stuff.",
"Administrators make all the decisions about how money will be spent. ",
"Assholishly I'm going to drag unions into this.\n\nAt my university admin positions were ruthlessly unionized meaning the worst employees couldn't be fired. And there were some doozies. So instead of being able to throw over lazy underachieving employees in the name of efficiency, they just have to hired more. \n\nA friend of mine worked in a department of our uni with an enormous admin. Her VERRRRY half-assed supervisor had two part-time underlings (one of them my friend) hired because she could manage to accomplish all her duties so she could play facebook games and roam reddit for hours instead.\n\nThe university was paying three people to do the job of one person. "
]
} | [] | [
"http://www.reddit.com/r/news/comments/1mxbk0/today_these_itinerant_teachers_make_up_a_whopping/"
] | [
[
"college.is"
],
[],
[]
] |
|
3n7y73 | what are the purpose of butt plugs? | Like do they stimulate something or? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3n7y73/eli5_what_are_the_purpose_of_butt_plugs/ | {
"a_id": [
"cvlljkb",
"cvlm5vh"
],
"score": [
14,
5
],
"text": [
"a) Sexual pleasure through anal stimulation during masturbation.\n\nb) A way to stretch out and exercise the sphincter muscles for easier anal sex, to be able to fit larger objects in one's anus and for more pleasurable anal sex.\n\nc) Please do not experiment with objects without flared ends in your butt. We don't want to see you in the ER.",
"The anus and rectum are full of sensitive nerve endings. To some people they feel good when stimulated. \n\nMore importantly, in men, the prostrate can often be stimulated via anal penetration (which most men find pleasurable; often equating it to a woman's gspot). In women, pressure through anal penetration can reach their actual gspot through the tissues of the body. It also may impart a similar sense of \"fullness\" that one gets from traditional vaginal penetration. \n\nA buttplug is often shaped so that the part on the actual anus is thinner. This allows a larger object to be inside the body without putting continuous stress on the sphinkter. The flared end on the outside prevents it from moving too deeply into the which can be quite dangerous as, unlike a vagina, there is not an \"end\" to the area inside the body. \n\n"
]
} | [] | [] | [
[],
[]
] |
|
4agyjs | why are cars in professional racing almost identical? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4agyjs/eli5_why_are_cars_in_professional_racing_almost/ | {
"a_id": [
"d10ac6q",
"d10aden",
"d10adhm",
"d10aitz"
],
"score": [
22,
10,
5,
6
],
"text": [
"Some classes have very strict rules about just about every aspect of the car. Some in fact run cars that are as close to identical as they can be made. The idea is to take the cars out of it and make it a competition of driver skill.",
"That's not true at all. It depends on the series. \n\nSomething like NASCAR mandates the same shape and car design for everyone on the premise that the determining factor is the skill of the driver. The cars are all of equal performance, so no driver has an advantage because of technology.\n\nOther series have less specific restrictions, based on horsepower, weight, or other factors. WRC for instance has different classes, but you see many different types of cars with different configurations in those races. ",
"Because you're not racing to see who has the best car, you're racing to see who is the best racer (with the best pit crew and build team etc.).\n\nIf you make the cars different, and that one guy wins...did he win because he's a better driver? Or did he win because he spent several hundred thousand dollars more than you to get a better car? That's not fair...or at least, not fair in a \"best driver\" competition. For stuff like street racing, you're also competing with who has the better car - but that reflects the person driving a lot more, since they're generally the ones who put the time and effort into putting it together. But in many professional racing sports, where people have sponsors, if you don't limit the cars to be as close to the same as possible, the winner is just the guy who either has the most sponsors or the sponsors willing to spend the most money.\n\nEDIT: Source: My dad is, unfortunately, really into NASCAR.",
"It depends on what racing you are referring to. For example Formula 1 cars look similar because of regulations. The governing body says \"your rear wing has to be within such and such dimensions\". As it turns out, the most efficient dimensions within those limits are always the same or very close.\n\nIn Indy Car, it's a combination of rules and limitation of chassis/bodywork suppliers. Indy Car bosses wanted to put the driver's skills at the center and also cut costs for the teams. So they decided to literally use the same car for all teams. They just change the colors.\n\nNASCAR is all about regulations."
]
} | [] | [] | [
[],
[],
[],
[]
] |
||
efb3yy | why do baloons do a huge bang when popped | [deleted] | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/efb3yy/eli5_why_do_baloons_do_a_huge_bang_when_popped/ | {
"a_id": [
"fbzds4t"
],
"score": [
5
],
"text": [
"The air in a balloon is at a higher pressure than its surroundings because the elastic tension of the balloon skin is pulling inwards. ... The high-pressure air that was inside the balloon is now free to expand and this creates a pressure wave that our ears hear as a bang.\n\nA simple google search told me that. . ."
]
} | [] | [] | [
[]
] |
|
5yl25f | why do camera lenses have to focus if they're capturing in 2d? | As I understand it our eyes need to focus because they're pairing two flat images to make it one 3D image with depth. Camera lenses, however, need to focus even though they're capturing in 2D, so I imagine there must be some different mechanism in there. What exactly is going on? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5yl25f/eli5_why_do_camera_lenses_have_to_focus_if_theyre/ | {
"a_id": [
"deqwioa",
"deqwjqu",
"deqwmk3"
],
"score": [
2,
8,
2
],
"text": [
"No, you are mixing two different things. Our eyes have to *converge* because they are combining two images. Converging is the action where your eyes turn slightly toward the center of your face, so they hit the same object from two different angles.\n\nOur eyes -- just like a camera -- also have to *focus* in order to turn the image from some distance into a sharp image on a fixed sensor. That's the retina in your eye, and the film or CMOS chip in your camera.",
"Our eyes need to focus separately for the same reason a camera does, and not because we see in 3d. Here's a simple experiment: close one eye and hold a finger right in front of the other eye. See how you focus on the finger and the background becomes blurry? Alternatively, focus on the background and the finger becomes blurry.\n\nWhen we look at a certain point in space, the light coming from this point enters our eyes at various angles. This is because the pupil isn't a single point, it has a certain diameter - some rays of light go through the bottom of the pupil, others go through the top, others go through the middle, etc.\n\nWithout a lens, all these rays of light will hit different points on our retina. In order to see clearly, we need all the rays of light coming from a certain point in space to reach the same point on our retina. That's what the lens does - it focuses the light to that point. The problem is that it can only do this for a specific distance - it can't focus on something close and something far at the same time. That's the reason we need to focus. Camera lenses do the same thing - focus the light coming from a certain distance.\n\n[Here's a diagram, I hope it helps.](_URL_0_)",
" > our eyes need to focus because they're pairing two flat images to make it one 3D image with depth\n\nThat's incorrect, our eyes have to focus for the same reason cameras do and it's not because of stereo vision. It's because our eyes and cameras use lenses. Take a look at [this image](_URL_1_) - the lens in our eye changes focuses to different distances by changing the shape of the lens. Cameras do the same thing differently - they can't change the shape of the lens, so they use multiuple lenses and adjust their positions by which the achieve the same effect.\n\nTo prove this further, you can take a look at [pinhole camera](_URL_0_), a type of camera that doesn't need to focus, because it doesn't use a lens and uses only a tiny hole instead. It's not very useful in practice, but is a nice simple model to get an understanding of how cameras work."
]
} | [] | [] | [
[],
[
"http://static.giantbomb.com/uploads/original/6/65562/2022820-accomodation.png"
],
[
"https://en.wikipedia.org/wiki/Pinhole_camera",
"http://static.giantbomb.com/uploads/original/6/65562/2022820-accomodation.png"
]
] |
|
3purw3 | what happens if you just keep applying skin lotion? | Like say to the same spot, several times a day. Would our skin get overly moisturized or would it just stop absorbing the lotion? What, if any, side effects would it have? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3purw3/eli5_what_happens_if_you_just_keep_applying_skin/ | {
"a_id": [
"cw9mbky",
"cw9o0qp",
"cw9rrn2"
],
"score": [
17,
8,
3
],
"text": [
"Eventually it'll stop absorbing. You'll get an awful rash from the friction. The skin will break down after several hours of light friction and slough off. It'll be like an awful sunburn. ",
"Why do you ask? Been \"moisturizing\" a lot lately?",
"You'd just get younger, right? "
]
} | [] | [] | [
[],
[],
[]
] |
|
1hdg9c | the implications of the recent scotus ruling on the voting rights act. | Both legally and practically, when taking into account the current demographics of the constituencies of the states who will be most effected. Also, how quickly could this decision be reversed if Roberts, Thomas, Scalia, Alito, or Kennedy died or retired and a more liberal justice was appointed by Obama or the next president (who I am just going to assume is going to be a democrat, because, seriously, come on.) | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1hdg9c/eli5_the_implications_of_the_recent_scotus_ruling/ | {
"a_id": [
"cat9edn",
"cat9hgj"
],
"score": [
3,
4
],
"text": [
"Section 5 of the Voting Rights Act says that certain states and counties, identified using a formula found in Section 4, cannot make changes to their election laws without having the federal Department of Justice or a federal court approve them, and to do so, the state or county has to show that the law will not have a \"retrogressive\" effect on minority voting rights - it can't be harder for them to vote, or give them less representation, etc., as a result of the change.\n\nA portion of Section 4 - the section which decided who is covered by Section 5 - was what was struck down, for being based on decades-old data which may or may not be still relevant (there are references to how things were in 1964, for instance). Congress could pass a replacement for it, and the SCOTUS opinion actually encouraged them to do so, but with the current Congress, it might be tough to do. It's not something that will be reversed in the sense that it'll go back to the old language if a new justice replaced a conservative on the bench - there *can* be Section 5 jurisdictions, just not the way they were identified before.\n\nIn practical terms, there is not much that could be passed and upheld in the courts that wasn't before (if anything). It's still illegal to have state laws that discriminate against racial minorities. Furthermore, most of the country wasn't covered under Section 5, so nothing changes there. It's just that in those formerly covered jurisdictions, ones that had a history of racial discrimination, laws could be passed and in effect for a while until a court struck them down that would have previously been not allowed to take effect from the beginning.\n\n > who I am just going to assume is going to be a democrat, because, seriously, come on\n\nThat's not a safe assumption by any means.",
"Ruth Bader Ginsburg summed it up pretty well (paraphrasing): The VRA was working just fine, even in 2006 when it was renewed. There was no cause to overturn it, it would be like getting rid of your umbrella in a rain storm because youre not getting wet. \n\nThe thing is, while it is true that states (especially in the South), no longer are trying to limit voting based on RACE, what they ARE trying to do is to limit voting based on party affiliation. They really do not care if a voter is black or not, they only care that certain voters happen to vote for Democrats, and it just so happens that these voters are minorities. \n\nIf all the minorities were voting for Republicans, then you can bet that the Republican led Southern legislatures would be passing as many bills as possible to actually HELP minorities vote as easily and quickly as possible. "
]
} | [] | [] | [
[],
[]
] |
|
9rwxlv | how does an infant transition from receiving oxygen through the placenta to breathing? how is there a constant supply of oxygen during labor? are there dangers to the brain? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/9rwxlv/eli5_how_does_an_infant_transition_from_receiving/ | {
"a_id": [
"e8k9mcp",
"e8kapvd",
"e8kcdch"
],
"score": [
8,
8,
5
],
"text": [
"The umbilical cord attaches the baby to the mother's blood supply, so the baby does keep receiving oxygen (through the blood) during the birth process. If you google it, the minimum recommended wait time to cut the umbilical cord is 2 minutes after the birth; so, basically, no, there is no interruption in receiving oxygen, or danger to the brain. The baby should cough out the amniotic fluid and breathe (and cry) before they cut the cord.",
"One part of the process is a change that happens in the heart. In the womb, there is a connection between the left and right sides of the heart. Oxygenated blood from the placenta passes into the pulmonary circuit to keep the developing lungs supplied.\n\nShortly after birth this passage closes to separate the two circulations and the pulmonary circuit is fed with veinous blood to be oxygenated. Failure to close properly often required surgery to repair the \"hole in the heart\" baby. Another possible problem is if the baby is delivered feet first. Cooling of the body in the outside air triggers the changes, but if the head is still inside the birth canal, breathing can't t happen so the head needs to be extracted quickly.\n",
"You're asking two different questions. \n\nDuring labor, especially in your baby's case when the baby was all wrapped up in the cord there probably wasn't oxygen flowing freely the entire time. During a uterine contraction the cord will get pinched (either partially or completely) or the placenta wont be exchanging oxygen well, flow will be reduced or stop temporarily (usually less than a minute or two) and then return. Its the same as you holding your breath for a minute, its harmless, the baby is still has plenty of oxygenated blood in its body. There are cases when babys dont get enough oxygen during labor, and we monitor that by watching the baby's heart rate. It dips and then returns to baseline its fine. If it gets too flat, or dips and doesn't come back up, etc we know there is a problem. We don't really think a baby's brain is being deprived of oxygen until that heart rate has been down continuously for at least 6 minutes and in that time we can perform a cesarean pretty quickly. \n\nThe transition itself is pretty seamless under normal conditions because there are shunts built into a baby's circulatory system to change the way blood flows. One of the triggers for closing those shunts and changing that circulation is the baby's first breath. But again, there is no harm in holding your breath for a minute or two. There are complications that prevents shunts from closing, fluid remaining in the lungs, babys not having the urge to breath etc, but these are rare and usually medically manageable. "
]
} | [] | [] | [
[],
[],
[]
] |
||
5srl31 | how are animals trained to sniff out drugs? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5srl31/eli5how_are_animals_trained_to_sniff_out_drugs/ | {
"a_id": [
"ddhb5tu"
],
"score": [
3
],
"text": [
"Basically the same way they are taught to sit or roll over\n\nDogs have an incredible sense of smell (like super freakishly good) - the dogs that are selected to become sniffer dogs are selected as ones that show both a strong talent and desire for that sort of work.\n\nFrom that it's just a case of (in ELI5 terms) just repeating a series of tasks and rewarding them when the do it correctly. So they are given a little bundle of drugs to sniff out - if they find the drugs they get a reward, if they don't they get nothing.\n\nAfter a while they learn what the drugs smell like and that finding them will earn them their reward so they do it. "
]
} | [] | [] | [
[]
] |
||
33dc6n | why aren't legless lizards considered snakes? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/33dc6n/eli5_why_arent_legless_lizards_considered_snakes/ | {
"a_id": [
"cqjs2ac",
"cqjs4ko"
],
"score": [
3,
2
],
"text": [
"We don't classify animals by what they look like - we classify them by their evolutionary history, and how close they are to their relatives. Lizards and snakes have been evolving separately for millions of years, but lizards with and without legs share a much closer ancestor, so we consider them lizards.\n\nThis isn't the best example, but it's why we consider bats to be mammals and not birds. Sure, they have a few obvious things in common with birds, but they have a lot more in common with rats, and from an evolutionary perspective, they aren't far off from rats.",
"It depends on where they fall on the evolutionary tree. Snakes and lizards diverged at one point. Some time later, a species of early lizards continued to evolve to have no legs. They are genetically closer to lizards than to snakes, but they happen to have no legs."
]
} | [] | [] | [
[],
[]
] |
||
348rv9 | does someone with stronger, bigger muscles have a greater resistance to pain than a skinny, scrawny person? | If a 6'5'', 110 lb. guy fell from a tree, would he be more prone to injury or pain than the 6'5'' 220, built guy simply because of the added muscle cushion?
| explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/348rv9/eli5_does_someone_with_stronger_bigger_muscles/ | {
"a_id": [
"cqscdlb",
"cqscj9f"
],
"score": [
3,
2
],
"text": [
"The 220 would be vastly more prone to injury and pain in this example due to weight. Imagine if at 110 he landed feet first with just an ankle sprain. Now add another 110 pounds and maybe that's a fractured tibia. \n\nIn some examples, like when people take cannon balls to the gut, sure strong muscles are why they can do that. However there is no general rule for this. Nor does the additional muscles some how numb up your pain receptors. ",
"Pain is a result of the firing of nociceptors, which are neural receptors specifically made to respond to pain ( & feeling in general). Pain tolerance is a mixture of psychological factors and biological factors. Psychological factors include mantras such as \"mind of over matter\" which many athletes tell themselves to endure the lactic acid burn that occurs during extreme aerobic exercises. Biological factors would include less responsive nociceptors, less opioid release, and things of that nature (Opioids are your body's natural morphine, which acts as an analgesic (painkiller)). \n\nSo would muscle mass/weight have anything to do with pain tolerance? Overall, I would not make that generalization. There are too many other factors to consider when examining an individual's ability to withstand pain."
]
} | [] | [] | [
[],
[]
] |
|
6910rp | why isn't it good to have a lot of vitamins at once? | I'm specifically talking about gummy vitamins/pills. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6910rp/eli5why_isnt_it_good_to_have_a_lot_of_vitamins_at/ | {
"a_id": [
"dh2tuul",
"dh2uhkk",
"dh2xvbo"
],
"score": [
7,
5,
3
],
"text": [
"The difference between a thing being healthy, and a thing being unhealthy, is quantity. Vitamins are necessary for human survival, but you can also overdose on them. Overdosing on vitamins can have various dangerous effects, depending on the particular vitamin.\n\n That being said, even if you don't eat enough to suffer complications from overdosing, then it is likely excess is going to be removed from your body. In other words, you're buying expensive candy and making expensive pee. ",
"Your body can only absorb and store a certain amount of vitamins at a time.\n\nIn some cases, the excess is just thrown away and wasted. In other cases, too much can actually make you sick.",
"There are two types of vitamins: fat-soluble and water-soluble. The water soluble vitamins are more common so if you take too much of these, you'll just pee them out. They do no harm.\n\nHowever, the fat-soluble vitamins are very harmful because they stay in your body and if you have too much, you can get very sick. For example, if you take too much vitamin D you might experience nausea, a loss of appetite, and vomiting. This is because too much vitamin D causes calcium to build up in your blood.\n\nTaking too many vitamins can be very harmful, just like most good things."
]
} | [] | [] | [
[],
[],
[]
] |
|
1ua17i | what characteristics does a film need to win an oscar for best picture? | Some movies that win don't necessarily get good reviews. For example I read a review for "Extremely Loud and Incredibly Close" in which the critic wrote that they believed the movie was made in such away that it would be considered for an oscar. I don't understand how this would be done without also making a quality movie. (the review was negative) | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1ua17i/eli5_what_characteristics_does_a_film_need_to_win/ | {
"a_id": [
"ceg0dco",
"ceg1rqh",
"ceg27aj"
],
"score": [
4,
2,
2
],
"text": [
"Most of the academy's voters must like it.",
"It's important to remember that critics do not vote for Oscars. Members of the Academy (directors, actors, cinematographers, screenplay writers etc) vote for the Oscars. A film needs to be well judged by its peers--which may mean that its being judged by people who know their shit or that its being judged by people who like to play favorites.",
"_URL_0_\n\nThis should help, This was posted on Reddit before.\n\n_URL_1_"
]
} | [] | [] | [
[],
[],
[
"http://i.imgur.com/LhS0fbY.jpg",
"http://www.reddit.com/r/movies/comments/1pi3nc/how_to_win_an_oscar_a_visual_demonstration_of_the/"
]
] |
|
9shz53 | why is falling so serious for older people? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/9shz53/eli5_why_is_falling_so_serious_for_older_people/ | {
"a_id": [
"e8ow5x7"
],
"score": [
4
],
"text": [
"Old people's bones are much more brittle, typically. With use, people's joints also get worn out, making a fall that much more serious. Also, skin deteriorates, making it easier for old people to begin bleeding. "
]
} | [] | [] | [
[]
] |
||
2ao70u | why does it seem like there are no unbiased news sources? | I prefer to form my own opinions and views on topics, especially things of a political nature. But I can't seem to find a news source that actually just gives me straight facts. (Especially not one within the US) Why has news become so focused on their political leans and why can't I find any sources that focus on just facts without injecting their opinions? Shouldn't news and politics be separate? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2ao70u/eli5_why_does_it_seem_like_there_are_no_unbiased/ | {
"a_id": [
"cix354w",
"cix37is",
"cix3bgf",
"cix3kt4",
"cix491y"
],
"score": [
22,
9,
7,
2,
3
],
"text": [
"Everybody has bias, even if they don't realize it.",
"To be human is to be biased, in one way or another.",
"In \"the good old days\" TV and radio networks all had news division, but never really asked or expected that they would make much, if any money. So long as the broke even, they were more or less happy and saw it as a public service and were, in fact required to offer a certain amount of local news by law. There were other anti-monoply laws that prevented any one owner from posses too many media outlets in one geographic region, thus skewing the information aailable to the public However, the 1996 Telecommunications Act \"deregulated\" many media industries allowing for entire markets to be owned by single individuals and/or corporations. As a result, now days almost all major news outlets are now owned by huge corporations who insist on profits above all else. They could care less if the information they offer is accurate, or relevant. It just needs to sell. Unfortunately, about the only way to make the \"news\" profitable is to make it as sensational, biased and/or outlandish as possible in the hopes that it will grab people's attention long enough for them to see an add, or buy the magazine. When profits are the only motive, people can, will and must do all sorts of things to meet their goals. While this fine and even beneficial in most industries, most of the time, it's poison in a profession like the News which is simply about efficiently conveying complex information to people on a daily basis, but has nothing to \"buy\" as such. It was meant to be a public service, not a profit mill. ",
"There's three influences on media: those that do things that are newsworthy (usually government of some kind), those that share the story (media companies), and those that consume the story (us). All three factor in.\n\nGovernments sometimes deliberately manipulate media (e.g. North Korea), but most simply don't share every single little newsworthy thing they do because they want to appear perfect and get re-elected. So they'll introduce bias that promotes themselves and deflects criticism wherever they can. This goes for all forms and agents of government, from the country leaders all the way down to the municipal police.\n\nOn media companies: As another answer pointed out, they're owned by people with their own biases. Those people can be more interested in telling THEIR perspective of the story than a totally neutral perspective that just shares the facts. And they want stories to be big and eventful so they'll get and keep customers.\n\nOn us: Most of us quickly lose interest in dry recitations of facts (or, even worse, absence of facts). Adding opinions and delivering with humor makes it more interesting for us, so more of us watch those types of shows. As a result, the dedicated audience for plain-fact news sources is too small to be cost-effective. This is particularly true when the media company is telling the story that we want to hear (like Fox News, for example, which really appeals to older Americans) or when the story is incomplete. Nobody wants to watch \"we don't know yet\" over and over again, so opinion and analysis fills those holes, and it's VERY difficult to have a truly unbiased opinion.\n\n",
"Because even the presentation of straight facts is biased. Suppose you hear just the facts about how many rockets fall on Israel and never hear facts about Palestinian houses being bulldozed. Would that be just the facts? Yes. Would it be the whole story? No. Would it be all the facts? No, but it is information-theoretically impossible to get all the facts. You just aren't biologically capable."
]
} | [] | [] | [
[],
[],
[],
[],
[]
] |
|
4wrelx | how do engineers build cpus with around two billion transistors in them? | To be more clear with my question, how can an engineer even account for all of the transistors? Two billion seems like a lot of work for logic gates and such. How can they fit them in there and know that it works? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4wrelx/eli5_how_do_engineers_build_cpus_with_around_two/ | {
"a_id": [
"d69cygt",
"d69dc7y",
"d69dcca",
"d69g543",
"d69kqcw",
"d69m96g",
"d69mnz7",
"d69nmhh",
"d69q79m",
"d69s86m",
"d69sq31",
"d69xarn",
"d6a3teo",
"d6a76sb"
],
"score": [
173,
12,
10,
147,
29,
3,
22,
2,
21,
2,
3,
2,
2,
3
],
"text": [
"They don't plot out each transistor by hand. They use higher level programming languages to do it.\n\nSomething called a Hardware Descriptor Language.",
"The process is fairly complex but to ELI5 grow a wafer and then print them using light.\nHere you go: _URL_0_",
"There are two things involved here - Logic Design and Physical Design.\n\nFirstly, if you are building from scratch, you start designing small blocks which have a definite input-output behavior. E.g. you can use these gates and make a block which performs addition. Now, and this is perhaps the most beautiful thing about digital circuit design, once you have designed and tested such a block you can use this block anywhere when you need its particular functionality. The only constraint is that the block will produce the output after a fixed time. As long as you don't rush the block (meaning, try to use the output before this fixed time), this block will behave exactly the same no matter where it is used. It's almost like using lego blocks to make bigger things.\n\nThis simplifies the design process a lot. Once you aggregate the transistors into gates, and the gates into even larger blocks, you don't really have to worry about the working of individual transistors.\n\nAfter the logic design, during the physical design phase, you do two things. Decide the physical location of all these blocks, and make sure that the timing constraints that I mentioned before are adhered to.\n\nTL;DR - The entire design is actually done in small parts which are then glued together.\n\nSide note - Most of the times, things are built on top of existing designs. So when you want to add something, you can safely assume that the rest of it is working fine unless you break it yourself. ",
"There are a few things going on here.\n\n1. Most of that really high count is from repeated functional blocks, like cache memory or cores. Even these high level blocks have repeated components in them. Something like 30-50% of these transistor counts are from high speed cache memory.\n\n2. The design of each of these blocks consists of lower level blocks which may, in turn, have lower level blocks. At some point there was probably an individual engineer responsible for creating and optimizing the lowest level components, but after that they are put together like Lego bricks. \n\n No single human understands all of the low level nitty gritty details of each functional block. Each block has standardized interfaces or interface requirements that other blocks are designed to interact with.\n\n3. There are synchronous \"programming\" languages like VHDL and Verilog which can be \"compiled\" into logic gates. The \"compiler\" can do optimizations on the logic which a human probably wouldn't be able to do. These languages allow for very complex logic to be spelled out in just a few lines of code. \n \n It may be possible that some subsets of transistor locations are placed \"by hand\" to optimize them for some critical usage, but that's increasingly unusual. ",
"I can speak on the construction side of this, since there's a couple very good logic-side answers.\n\nPhotolithography plus chemical vapor deposition and ion implantation are the magic steps behind making such small devices. They know they work because the circuits are organized on the wafer such that a signal or set of signals can be input on the outside and an expected result can be measured elsewhere. This is done with probes, metal contacts that are placed on the wafer by robot to test.\n\nPhotolithography is the use of light and light-sensitive chemicals to mask part of the silicon wafer so other processes can be applied to the entire wafer, but they only \"stick\" to the wafer where there is or is not lithographic material (depending on whether they used positive or negative lithography). Photolithography is done before every other step so each step is only applied in a certain area, and after that step is complete, the lithographic material is washed away, often with a strong acid, and a new layer of lithographic material in a new pattern is applied.\n\nChemical vapor deposition is using gases to deposit atoms on the surface of the wafer. Think of it sort of like electroplating but with gas instead of water.\n\nIon implantation is exactly what it sounds like; a beam of ions is fired at the wafer at a specific intensity to achieve a certain penetration for a certain time to achieve a certain concentration. The wafer is then heated to \"even out\" the implanted areas. This is used to \"dope\" the wafer to a certain concentration of impurities. You want impurities to make your ~~semiconductor resist unintented signals from passing, but you want them to be pure enough to allow intended signals with as little losses as possible.~~ charge carrier concentrations accessible to your control signals. You need sections charged positively and sections charged negatively to create the circuits (PN junctions)\n\nI can answer other questions people have on the subject. I know the theory on it and my brother in law works in a Samsung fab.",
"I'm building a Lego castle(CPU). I imagine what I want my castle to look like(Floor planning). To build it, I need 20 lego windows, 5 lego towers, one or two lego gates. I build 1 lego window using few lego bricks(transistors) and then I check if it looks lego window-y enough(simulations). If it looks good enough for a princess to peer out of, it's good enough for me. I now proceed to make 19 copies of that window using the same kind of bricks used to make that one window. \n\nSame method for the towers and the gates. \n\nI then put it all together to form one big castle which is able to run Crysis on Ultra High settings.",
"For those looking for an ELI16 or older type response.\n\nSilicon wafers are covered with a photo-reactive coating and have an image flashed on them. It's like a Polaroid image kind of.\n\nThen wherever light was shown, the coating gets hardened. The remainder is then washed off.\n\nNow we have a skeleton molding of the circuit diagram with raised outlines. They fill the skeleton molding with copper and then sand/polish all the excess copper off. \n\nThis creates a near perfect circuit.\n\nIt's essentially finished at this point - so they take a tool with 1000's of electric prongs on it and they connect it to the circuit to run through all testing. All the testing is automated here to ensure the base functionality works and to measure different performance metrics.\n\nAdditional info:\n\nMultiple CPUs are printed onto each silicon wafer in small square sections. They're then cut out to be used. What's crazy is that chips from the same wafer can have different performance measurements due to inconsistencies at the atomic level. These different performance measurements then classify which type of chip was created. So a 2.4Ghz chip and a 3.2Ghz chip can be made at the same time with literally no difference in the entire process. These classifications determine if it's a high-end expensive chip or a low-end cheap chip.\n\nThe transistors themselves are all created during this process at once by way of applying different layers of substances/coatings/copper to the wafer disks to create the necessary chemical/electrical pathways and reactions that take place at that low level in the transistor.\n\nThen multiple wafers are layered together to create the super complex diagrams.\n\nThe copper structures/wires ends up looking like the skeleton of a building with copper plumbing running everywhere and connecting different systems.\n\nTldr; Transistors aren't individually created - they are all printed at once after creating the very detailed schematics. It takes teams of engineers years and thousands of revisions/designs to design the type of chips being printed today. Automated systems test all expected behavior of the chip to verify functionality without the engineers having to individually check the transistors.\n\nEdit: here is a great [video on the entire process](_URL_0_) ",
"They shine a light on a piece of photosensitive semiconductor. What doesn't get exposed to light by a mask will not be etched away in the subsequent process, so will have circuits on it. By layering substances which don't want more electrons(negative type, n-type) and substances that want electrons (positive type, p-type) they can be created.\n\nTransistors are gates which can allow electricity to flow or not flow depending upon an applied voltage.",
"Think of it like a large planned suburban community. Vast acre of nearly identical houses on a perfectly gridded road. For the most part there are only a handful of designs, just repeated multiple times. You connect these multiple copies of houses together with small roads to get the people in and out. You copy the neighborhood just next door and connect then with larger roads that can handle heavy loads of traffic. You repeat that a few more times until you have to build a major highway. And that's the basics for vhld design.",
"To you first question - An engineer cannot account for all those transistors by hand. There are teams of engineers with automated tools working in concert to design, build, and test these CPUs. There are some other answers here regarding manufacturing but you should specifically look up designed for test and test.",
"Engineer here.\n\nWe're really fucking careful.\n\nSource: I'm a quality engineer at an automotive manufacturing plant. I don't know shit about other engineering disciplines, I just hate getting grouped in with every other engineer because we are vastly different.",
"Code is written in a language such as VHDL and Verilog which is able to auto create and organize the wires in the most efficient way possible automatically. The engineer simply writes the code that describes which wires attach to which transistors, the engineer doesn't have to worry about board \"real estate\". The code builds the layout map.\n\n \nFabrications can be done through FPGA which are basically programmable hardware that has the transistors pre built or they start a new from scratch integrated circuit.\n\nIntegrated circuits are built using a process known as photolithography. A filter is layed over a silicon wafer and an image is shined on the filter. The image is the map created from the Verilog code. Parts of the filter that were exposed to the light dissolve under a chemical and the unexposed parts survive. Now the filter will allow us to dissolve, deposit metals, and inject boron and phospohous atoms according to the precise pattern of the image. Multiple photolithographies build the wires and create the transistors.",
"Nobody can account for all of them, so let me try to explain how it all works.\n\nFirst, there is a whole bunch of engineers working on a single or small batch of transistors. They make sure that for the size and speed, they work exactly like they want: a switch that you can activate with a voltage. They do a LOT of tests and it takes a lot of time.\n\nSecond, another whole bunch of different engineers work with special program languages that activate switches in certain orders and arranges them to create simple functions (VHDL for instance). The program transforms the driven-switch behavior, in useable commands like add, multiply etc.... These modules are then tested using the transistors made before.\nOnce the modules are ready, it is time to use very specific scripts and simulation engines that will try to put all of them nicely on a chip. It is called VLSI (very large scale integration). The role of this step is to use as little space as possible, and have as little interference as possible between switches. See, at high frequency, electricity doesn't always care for small obstacles, and sometimes tunnels from one switch to another. Thankfully the process is well understood, and the specfic tools try to take it into account as much as possible. At this point, some engineers will have an overview of the result, to add some markers for production for instance, or reorganize in a more esthetic way, but the only tests that can be done is make sure all the functions work the way they should on prototypes. This is done using FPGAs, which are chips on which you can actually program silicon (cool, huh!), then on test runs using actual silicium.\n\nLastly, they make some very precise masks to etch the silicone into chips. The way you build a trnsistor is not piece by piece. Instead, it is stack of layer on top of another. The electrical effect used actually propagates without contact into the silicium. Strange, but that works. This means that digging into layers of silicium, you can assemble transistors just like you can have a piece of ham connecting two sandwiches. Just here, the ham is a piece of conductive material, and the sandwich is a transistor.\n\nIf all the steps are done well, then you can have billions of transistors and thousands of complex modules (who said vertex shaders?) into a relatively easy to manufacture chip.",
"One possible ELI5 (the one I use, I am a digital engineer - I work at one step of the process to design chips). \n\nThis is a bit like software developers. We write a code that describes functions in a (more or less) human-friendly manner. Then we use tools (compilers for the software guys synthethisers for us) that translate those blocks into lots of smaller, much simpler blocks. Then, we use tools to arrange those blocks and order them in an optimized way (so they take less space in the chip, etc.) \n\nWe (almost) never deal with transistor-level stuff. \n\nELI4: if we were designing a house, we would work as follows:\n\n- we write a list of the rooms in the house (one sleeping room with a bed, connected to a living room with a kitchen spot, connected to a bathroom with a shower and a toilet, then the living room is also connected to the outside). \n\n- we pass this code to software that translates it into basic parts (the shower has a bottom, connected to the floor, some glass, connected to the roof, the wall, and a shower head, connected to the water network). It creates and optimizes pipes to run through the house, as well as power lines, etc. \n\n- this list of components is then passed to another software, along with some constraints (the shape of the house, the area of the rooms, and so on), that draws the final plan for the house. \n\nSo we don't manage every single wood fiber or plaster drop. We describe everything in a human-\"friendly\" manner, then software does the rest. \n\nOn a side note: don't feel dumb if you have difficulties grasping how it works in depth, it's a very uncommon topic that most people don't know about. It takes a few years of active studying to learn how to do this stuff, and even then, you have a hard time connecting all the dots ;) \n\nTL;DR: read the ELI4 only"
]
} | [] | [] | [
[],
[
"https://www.youtube.com/watch?v=qm67wbB5GmI"
],
[],
[],
[],
[],
[
"https://www.youtube.com/watch?v=-GQmtITMdas"
],
[],
[],
[],
[],
[],
[],
[]
] |
|
11h5ev | how does duracell powercheck work? | How does pressing on two little circles on the battery show how much charge is in it? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/11h5ev/how_does_duracell_powercheck_work/ | {
"a_id": [
"c6mg9vs",
"c6mh21j"
],
"score": [
51,
7
],
"text": [
"We should get someone with an electronics degree to answer this properly, but my understanding is that by pressing down on this strip you close a contact, effectively short-circuiting the battery with a heat-sensitive strip acting as a resistor. The higher the voltage, the more of the strip is changed/turned transparent.\n\nI assume it's similar to coffee mugs that change their image depending on temperature.\n\nBut again - this is my limited understanding.",
"There's a thin strip of material that conducts electricity and acts like a resistance. When you press the two points on the battery, electricity from the battery can go through the strip of material and this strip warms up.\n\nOn top of this strip of material, there's a layer of a substance (can be a very thin sheet of plastic) which changes color depending on the temperature - this propriety is called Thermochromism : _URL_0_\n\n \n"
]
} | [] | [] | [
[],
[
"http://en.wikipedia.org/wiki/Thermochromics"
]
] |
|
4k3ndh | how do those infomercials/commercials selling products know when you "call within the next 10 minutes" for whatever they addon for free? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4k3ndh/eli5_how_do_those_infomercialscommercials_selling/ | {
"a_id": [
"d3bukml",
"d3bulvf",
"d3buzoo",
"d3bwt0s"
],
"score": [
6,
4,
2,
8
],
"text": [
"They don't actually know, and they don't actually care. That deal is the same price you can always get, regardless of when you call. They simply put a countdown in the advertisement to encourage impulse purchases.",
"Generally, they don't. It's a marketing gimmick to instill urgency in the purchase decision. The more time you have to think about it, the more time you have to decide you don't really need to buy it.",
"Those commercials are airing on various channels, at various times, so it's always within ten minutes of the airing of one. As previously stated, they do it so you feel an urgency, and buy on impulse.",
"I'm going to disagree with the other posters here, only because I have a little bit if experience dealing with purchasing commercial space. My dad ran a call center years ago, and would get an update each morning from the marketing department detailing when and where commercials where going to play, as the center could expect a bump in call traffic at those times.\n\nCommercial slots are purchased by the channel and time slot. Someone in the infomercial company knows pretty closely when commercials are going to play, and where in the country those commercials will run. \n\nThat said, the infomercial company has little concern with when you actually call in comparison to the times the commercials run. They'll still give you the 10 min deal regardless. The reason that it is included in the commercials is to convince the average watcher that they need to call immediately, and not to wait. This psychological trick pops up all over the place, from weekend only appliance sales to real estate agents telling you that other people are also interested in the house. It works very well."
]
} | [] | [] | [
[],
[],
[],
[]
] |
||
235dm0 | why do restaurants tend to dim their lights during service? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/235dm0/eli5_why_do_restaurants_tend_to_dim_their_lights/ | {
"a_id": [
"cgtm8ke",
"cgtmd6d"
],
"score": [
2,
5
],
"text": [
"Well when you go to have a relaxing dinner after a long day at work would you rather have highly stimulating bright light blazing like the noon sun or would you rather have a nice soothing relaxing soft, dimmer lighting?",
"Darker rooms that have a light source on each table cause each table to feel more private, as each guests eyes adjust to the light on the table in front of them and the people lit by that light, making it more difficult to focus outside of that area. By keeping people focused on their table, they're going to hopefully enjoy each others company more, stay longer, buy more drinks, and ideally remember the good time they had at my restaurant.\n\nSource: Years and years in the restaurant and catering business"
]
} | [] | [] | [
[],
[]
] |
||
2iofhn | why dogs and cats are considered to be "enemies"? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2iofhn/eli5_why_dogs_and_cats_are_considered_to_be/ | {
"a_id": [
"cl3z6d8",
"cl40hmk"
],
"score": [
10,
5
],
"text": [
"Dogs hunt smaller animals than them. Cats are hunted by bigger animals than them. It's a dog's instinct to chase things that run from them. It's cat's instinct to run from things that are chasing them. ",
"Decades ago, cats and dogs were outdoor pets, and often allowed to roam their neighborhoods. Cats are about the size of the animals dogs instinctively chase, and cats aren't crazy about being chase and have the means to defend themselves when necessary. This lead dogs and cats to be wary of one another.\n\nThese days, cats and dogs are primarily indoor pets, and given their close quarters, tend to get used to each other and coexist in relative harmony."
]
} | [] | [] | [
[],
[]
] |
||
50d4px | what's the difference between east coast and west coast rap? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/50d4px/eli5_whats_the_difference_between_east_coast_and/ | {
"a_id": [
"d732bo9",
"d732wxw",
"d734fnr",
"d737j96",
"d73azrm"
],
"score": [
16,
9,
14,
14,
4
],
"text": [
"I don't think it matters much anymore as today's music is bleh, but back in the 80's/90's when the \"East vs \"West\" was a thing, i'd say the east coast was a little more poetic/heady/intellectual and the west coast was a little more gangster/chill. West coast always seemed a little more \"This is me and this is my environment\" and East coast was \"This is what i think about my environment\" I always liked the east coast stuff better for the lyrics and the west coast for the music. Bothsides had all different kinds of artists so it's really all the same. The publicized \"Beef\" was more about stirring up controversy to sell records. Rappers are like pro fighters, they need a good angle to get fired up and make a lot of money.",
"I'm not a hip hop historian, but..\n\nEast coast: Fast paced, lyrically dense, emphasis on prose, maybe more 'angry'.\n\nWest coast: Groove paced, some breathing room around lines, emphasis on flow, maybe more 'mellow'",
"Back in the nineties, west coast beats used synths heavily, harder drums, as east coast was more melodic. West coast was heavier into rapping about gangbanging, as east was more into story telling. Now days you can't tell them apart as everyone has mixed styles together. ",
"As others have said, there was really only a distinction during the 1990s. East Coast rap, with artists such as the Wu Tang Clan, Biggie Smalls, Nas, Mobb Deep, they all preferred heavier beats, and they emphasized lyrical storytelling above all else. The beat was there to keep the rapper grounded in his message and to keep the rhythm going, but it wasn't necessarily the focus of the song. You mostly listened to them for the lyrics and storytelling. West Coast rap was defined by artists such as NWA (and then Dr. Dre), Tupac, Snoop Dogg, and Warren G. They tended to have two main styles of song: statement songs, which NWA liked to do, and which focus on a theme and message rather than telling a story; and g-funk, where the beat itself gets as much (or more) attention than the lyrics themselves, which uses more synths, and where the lyrics flow into each other more (at the expense of lyrical complexity).\n\nOf course, as others have also mentioned, these trends were not definitive, and there were plenty of exceptions on both sides. And the East Coast/West Coast theme died out in the early 00's, as rap became a lot more decentralized, and as big artists started emerging from places that did not fit the West/East Coast mold; in particular, Southern rap became its own unique thing.\n\nThat said, the personalities of rappers are often still driven by their birthplaces, and style still sometimes shows itself. ",
"[This guide](_URL_0_) helps illustrate the connections different types of music have. Go to the breakbeat tab, and you can listen to the difference between East Coast and West Coast rap."
]
} | [] | [] | [
[],
[],
[],
[],
[
"http://techno.org/electronic-music-guide/"
]
] |
||
fxwekm | how do surgeons treat injuries they've never seen before? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/fxwekm/eli5_how_do_surgeons_treat_injuries_theyve_never/ | {
"a_id": [
"fmyfyj2",
"fmwtkmq",
"fmwtmh5",
"fmwtwv7",
"fmwuf2v",
"fmx0dbk",
"fmx427w",
"fmxcu6y",
"fmxglty",
"fmxr8lc"
],
"score": [
2,
3,
22,
11,
10,
3,
6,
3,
2,
4
],
"text": [
"Better to r/askdocs about this.",
"6 years of school + 2 years of residency + years of experience to work up from routine surgery to er surgeons.",
"There is a large body of evidence and past cases to draw on, but of course no human can ever remember it all. The nice thing is that humans are built more or less the same way; the stomach leads to the intestines, there are two kidneys, etc. The goal is to get back to that, or as close as you can, while having the person keep living. So if you find a chunk of something that's screwed up beyond repair and the person doesn't need it, take it out. If they need it and it might heal or keep working, leave it in there. If it gets worse, you might have to start looking for a donor.",
"Years of schooling. Checking available resources. Also, you don’t need to learn how to, say, shorten intestine for every different injury. You just need to know how to remove some intestine to get rid of the worse damage and reattach. That part is essentially the same if it’s draino that caused damage or a bullet.",
"Experts don't usually use specific knowledge to solve a problem, but build a solution from general knowledge. In the case of Draino, you have a chemical problem caused by consumption of a non-safe liquid. What the surgeon will be looking for is what organs have been damaged by this, particularly to the point where they are no longer functional. Then the surgeon is going to use knowledge about what can be repaired, what can fix itself if given the correct conditions (removal of the thing causing the harm and the amount of strain/iritation put on it for a period of time) and what needs to be removed or replaced. Surgeons also know things like how critical different parts of the body are for continuous function (For example, you have very little time that you can go without a heart, but you can continue indeffinately without toes), and can use this to evaluate what they treat when.",
"Thankfully, although the human body is complex, there are predictable patterns in the ways that injuries or diseases affect the human body. Also, humans are actually not that inventive when it comes to ways of harming themselves. For example, the specific thing you asked about, swallowing Drano, is a relatively common method of self harm. So much so, that there are grading systems for this type of caustic injury to the esophagus and stomach, and guidelines for what to do with each grade of injury. Guidelines for this problem, and thousands of others are based on scientific study of large numbers of patients. It takes years of training, reading, and practical experience to know what to do in different situations. Ultimately, it is a surgeon's clinical judgement, based on all of that experience, that allows them to decide what to do, even in situations that are \"not in the textbook\"",
"Surgical Resident with a couple years under my belt here. \n\nThere is a huge amount material that we have to remember and that get tested every year. Not to mention we get constantly pimped by our bosses and senior colleagues. \n\nNot going to get into the nitty gritty, but surgery is actually fairly straight forward all things considered. When there is an injury somewhere, you either 1) Repair it, 2) Remove it, or 3) Divert away from it. \n\nTake your Drano example: Drano is a base and generally cause horrible damage to your esophagus. It's probably not something that can be repaired unless it was just a very small amount, in which case you'd just watch. You remove the entire esophagus (ie. Esophagectomy) and stick a gastrostomy tube to feed them in the mean time if you can't reconnect it. Or, if the condition is so bad that the patient can't even tolerate that, you make a fistula (ie. esophagostomy) to divert whatever is going down so it won't further contaminate the injury, and then of course set up a route distally to feed them.",
"Physicians are trained to understand chemistry to a high level, because we are made of many molecules and compounds.\n\nOur bodies work on a principal called homeostasis, which is the attempt to keep our internal environment in the narrow range that allows us to live.\n\nPart of that is an acid-base system, and so understanding acids and bases are in the training physicians recieve.\n\nSince draino is a base, we understand that there is a severe case of alkylosis, and since hydroxl molecules are very reactive we know they can cause tissue damage. \n\nTHEREFORE: treatment would be to attempt to remove contact with the ingested draino, to ensure the acid base balance is maintained, either by removing the hydroxyl or by converting it to a weak base or neutralizing it into salts to prevent further damage. Finally, we must remove any dead tissue and promote an environment that can allow any damaged but functional tissue to recover.\n\nThus the bowel resection was necessary due to damage. \n\nNote: I am not a physician but I am studying medicine, so the treatment with carbonic acid (H2CO3) was essentially an educated guess on treatment, although neutralizing the base is an obvious treatment.",
"By knowing what the human body is supposed to do, identifying what the injury is making it do differently, and implementing a solution that reproduces the originally intended result, even if it's not necessarily exactly the same as it was before.\n\nI'm not a surgeon. I work in repairs. One of the ways I learned to do what I do is to look at two identical tools: one that works correctly and another one that doesn't. To ascertain the cause of the fault in the nonfunctional tool, I'll look for discrepancies between them, such as moving parts in the working tool that aren't moving in the broken tool.\n\nSometimes, you don't need to know a part number or have an identical matching part to fix a tool. For example, the throttle linkage on a small engine is just a metal rod bent in a particular way -- nothing I can't reproduce with an improvised metal coat hanger crudely bent into roughly the same shape. Or I could just bypass the throttle trigger and linkage entirely by tying a string to the carburetor choke that I operate by hand.\n\nSurgeons have the advantage that human bodies are mostly intended to do all the same thing and can implement creative ways to make sure an injured body is still able to do it. That's why, for instance, a colostomy bag is successful. The original intent is to have waste leave the body via the anus, but the body doesn't necessarily need to use the anus specifically as long as waste leaves the body somehow.",
" > I assume that doctors don't learn about the specific problems that affect Drano consumers\n\nNope, we do. Caustic ingestions are not uncommonly encountered emergency room and surgical problems. There are general DOs, DON'Ts, and things to watch out for. For many ingestions, we will touch base with Poison Control, who can offer help with management. We also learn about a lot of other ingestions and how to manage them, like Tylenol, NSAIDs, benzos, opioids, button batteries, magnets, other foreign bodies, etc.\n\nThis is why it takes so long to be one of these specialists. A general surgeon will have typically completed 4 years of undergrad, 4 years of medical school, then 5 years of general surgery residency before practicing on their own. The whole point is that you see **a lot** of cases with supervision before you are practicing on your own. The typical surgery resident will see multiple ingestions like this before they graduate, will be familiar with what needs to be done, and what to watch out for.\n\nIt takes years, and thousands and thousands of hours of work to build this knowledge base. This is why an 18-24 month program after undergrad to be a nurse practitioner or physician assistant is not equivalent in any way to becoming a board certified physician."
]
} | [] | [] | [
[],
[],
[],
[],
[],
[],
[],
[],
[],
[]
] |
||
3977hx | why is it that when i zoom in on an image it gets pixelated but when i take the same image and use a projector to blow it up on a wall it retains its resolution? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3977hx/eli5why_is_it_that_when_i_zoom_in_on_an_image_it/ | {
"a_id": [
"cs0x6qw"
],
"score": [
9
],
"text": [
"It doesn't. Walk close to the projected image and notice it looks a bit worse. The further away you stand the better something looks. The Projector usually casts the image further away from you than the arms length separating you and your monitor. \n\nHowever, another reason is that the projected image actually is blurred. The light isn't cast perfectly crisp and the pixels blur together and smooth the image out a bit making it appear better. your monitor however retains the clear pixel by pixel definition where the pixel boundaries are not blurred. "
]
} | [] | [] | [
[]
] |
||
49jlkz | why is a goods lorry's container rectangular, but a petrol tanker's is cylindrical? | [deleted] | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/49jlkz/eli5_why_is_a_goods_lorrys_container_rectangular/ | {
"a_id": [
"d0s9kob",
"d0s9pbb",
"d0s9pok",
"d0s9u6o",
"d0smt2n"
],
"score": [
31,
5,
3,
2,
2
],
"text": [
"Solid cargo generally needs a floor to be place on. If you have a bunch of boxes it's easier to pack them into a rectangular carriage than a cylindrical one.\n\nWith a liquid this is not the case. Instead, you're worrying about how much stress the structure can take from the pressure of the liquid. A cylinder is way better than a rectangle in this regard.",
"Spherical objects are good storage containers because they are generally stronger than their rectangular counterparts and have a higher volume to surface area ratio which means more efficient storage. However, spheres can be bad for storage because they don't stack well and it's hard to fit a sphere onto a surface without it rolling away. \n\nA lot of solid goods are shipped in rectangular containers because the ease of stacking and safe storage outweigh the benefits of a slightly stronger and more economical container. Liquids, however, don't need to be stacked and will fill any shape into which they are put. Therefore, when storing or shipping liquid it makes more sense to use a spherical container. Of course you still have the issue with spheres being hard to strap down (and also being as tall as they are wide) so they use cylinders instead.",
"Exactly, a round container reduces the sloshing of the liquid. The round walls also increase the structural integrity of the tank. Given the fact that often those types of trucks are carrying hazardous chemicals or heavy liquids (water, oil, acids, gasses, etc.), a strong structure prevents leaks and rupturing if the tanker is hit.\n\nIt's not perfect, but it's better than nothing.\n\nConversely, the rectangular trailer is designed to maximize the internal volume within a given height and width. Since those limits are defined with rectangular coordinates, the container is also rectangular.",
"It is much easier to drain a liquid from a cylinder with a low point than from a flat rectangle with no low point.",
"It's a combination of a round container being stronger compared to a square and having less wall for the same volume. \n\nFor boxes, the walls don't have to contain the load in the same way - the load supports itself from the truck deck and is tied down if it's too heavy. They also need to be stacked efficiently which square shapes are good for. \n\nLiquids exert pressure on their container and fill the space whatever shape it is. \n\nThe weight and overall dimensions of a road going vehicle is what limits how much it can carry. Boxes often carry large but light weight loads so you want to maximise the volume you have because weight isn't necerrarily a problem (think packages full of small things with lightweight lacking material to protect them)\n\n Most liquids that are bulk transported are heavy enough that the weight limits the load more than the volume so you want to minimise the weight of tank compared to the volume it can hold. Cylinders are very strong shapes and have low surface area to volume so are the most efficient and easy to build option for bulk liquid tanks"
]
} | [] | [] | [
[],
[],
[],
[],
[]
] |
|
23judh | why does confetti make the video quality go waaay down in a video? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/23judh/eli5_why_does_confetti_make_the_video_quality_go/ | {
"a_id": [
"cgxp8wu",
"cgy9q2p"
],
"score": [
13,
2
],
"text": [
"video compression works by identifying portions of a video frame which stay the same between the previous frame and current one, or by identifying portions which haven't changed in appearance much but have moved over a few pixels. taking advantage of temporal features like this is why videos are much smaller than a million jpegs and an mp3. \n\nconfetti fucks this all up because each piece is super small and moves more or less randomly, giving the video compression algorithm very few reference points between frames which stay the same. thus, there are no temporal reference points and the video encoder must store each frame without any carried-over information from the previous one. in order to keep the video's size and bandwidth within limits, the encoder must reduce the quality of these frames. ",
"I elaborated on /u/littleperson's explanation [here](_URL_0_), with example pictures. Hope it helps!"
]
} | [] | [] | [
[],
[
"http://www.reddit.com/r/explainlikeimfive/comments/23judh/eli5_why_does_confetti_make_the_video_quality_go/cgy9n05"
]
] |
||
72ckrf | what's the difference between ln and log? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/72ckrf/eli5whats_the_difference_between_ln_and_log/ | {
"a_id": [
"dnhfanz",
"dnhg7fn",
"dnhhav5"
],
"score": [
5,
8,
4
],
"text": [
"The log(x) operator is usually expressed as base 10, or essentially the opposite function to 10^x. \n\nLn is short for natural log, or log base 'e' (approx 2.71828) or the opposite of e^x. ",
"There are bunch of different logarithmic functions, which are equal to one another save for some constant multiplier. So Log(in base 10) equals roughly 3.3 x Log(in base 2). \n\nSo to avoid confusion, some of these logarithms have their own symbol. Ln refers to specifically one that uses number e as its base. Lg is typically used to refer to logarithm in base-10. Mathematicians love the number e based logarithms, and it's sort of the natural choice, but schools tend to like teaching students logarithms in base-10 since 10 is easier number to grasp(base-10 logarithm basically tells you how many digits you need to write down a number, minus one, so for example, without knowing anything about logarithms beyond that, you can tell that 445,483,182 has base-10 logarithm of roughly 8 since the number has 9 digits. Pretty easy to explain).\n\n\"log\" without any explanation can refer to any logarithm really. It's sort of confusing, but sometimes it doesn't matter because the constant multiplier disappears from calculations somehow. Also sometimes it's implicit which logarithm you're supposed to be using. In maths, log refers to natural log, ln. In computer science, it refers to base-2 logarithm because binary number system they use. In many other cases it's base-10, since that's the number system people in general use.\n\nIf it's not explicitly or implicitly clear which logarithm does log refer to, and it matters, then you gotta ask from whoever it was that used that logarithm. To explicitly mark the base, you typically write it like log*_10_* 445,483,182",
"A logarithm is the opposite of exponentiation. Just like you can undo A+B = C by starting C-A = B or you can undo A×B = C with C÷A = B, you can undo A^B = C with Log*_A_*(C) = B. We would read this as \"log base A of C equals B.\" Just like division and subtraction the logarithm takes two numbers and yields a result. \n\nUsually there are only a few bases you care about. One common base is e. This is so common that instead of bothering with \"log of base e\" we just shorten it to \"natural log\" which is written ln. \n\nAnother common base to use is 10. When using a log of base 10 you can call it the common log, which is often written simply as Log. \n\nBe careful that you know the context, though. Some fields are really fond of using log and meaning a different base. For example, computer science frequently uses log when the base is 2 (binary log). Others will assume log is a natural log. \n\nIf no base is specified then log can usually be assumed to be the common log, just be careful. If you see ln then you can be pretty certain it's a log of base e. "
]
} | [] | [] | [
[],
[],
[]
] |
||
4cgy07 | why is it better to drink liquor and then beer? | I've always heard the phrase, "liquor then beer, in the clear. Beer and then liquor, never been sicker." I was wondering why | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4cgy07/eli5_why_is_it_better_to_drink_liquor_and_then/ | {
"a_id": [
"d1i1xmo",
"d1i2c1b"
],
"score": [
2,
8
],
"text": [
"That's an old wives tale that isn't exactly true, alcohol is alcohol. That being said the reason I believe they say liquor before beer is because say you have 3-4 beers in your stomach and you start doing shots. Your stomach can only process so much liquid at a time so while it's working on digesting you are increasingly the total alcohol % of said volume. If you are already drunk you can accidentally take too many shots rapidly without immediately feeling the effect because it's diluting into a larger volume. The delayed feeling can lead to over drinking which will literally sit in your stomach like a time bomb, absorbing more alcohol even after you have stopped drinking. If that makes any sense.",
"So for the most part alcohol is alcohol. If you drink two beers one hour, then have two beers worth of liquor the next hour, your body won't do different things than if you did that in reversed. \n\nWhat's really important is perception, hydration, and when to stop.\n\n If you start out with liquor, youre absorbing a lot of alcohol quickly but you aren't near your limit. Then you switch to beer as you approach your limit. Generally people take a lot longer to finish a beer than a shot, and you start to get full on beer, so you slow down. This means you're approaching your limit at a slow rate. \n\nYour body takes a little while to absorb the alcohol (you don't instantly feel drunk after pounding four shots in ten seconds it takes a while ) , so even after you stop your still getting a little more drunk from the stuff you've already drank but are still absorbing. \n\nSo when your body says woooooah I'm drunk and starting to feel bad, you stop drinking, there's only a little more alcohol in you to absorb, you get a little but not a lot worse, and can handle it. \n\nThe other way around you are downing some beers and absorbing alcohol slowly. The you get a bit tipsy and start doing shots. Now you are consuming alcohol quickly, and when your body tells you \"OK I'm not feeling good, slow down\" you've got a lot more alcohol in your system, because you were taking in alcohol more quickly so got more inside you in the lag time between drinking and feeling it. \n\nSo you aren't getting sick from the order. You're getting sick from the amount of alcohol. If you drink at the same amount of alcohol per hour regardless, order won't matter to you. \n\nSome other factors enter play, like how much water you're taking in per amount of alcohol, because dehydration is also one of the major causes of feeling unwell later from drinking. "
]
} | [] | [] | [
[],
[]
] |
|
389i7o | how do some drinks make you pee quicker than other drinks would? | If I drink a cup of coffee, I'll have to pee sooner than if I drank a cup of water. Why is that? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/389i7o/eli5_how_do_some_drinks_make_you_pee_quicker_than/ | {
"a_id": [
"crtdeyr"
],
"score": [
32
],
"text": [
"Caffeine and ethanol are [diuretics](_URL_0_), substances which encourage the body to produce urine."
]
} | [] | [] | [
[
"http://en.m.wikipedia.org/wiki/Diuretic"
]
] |
|
1eg4qq | why are boxers topping the list of highest-paid athletes? | Professional boxer Floyd Mayweather, Jr has been ranked as the highest paid athlete the last two years by forbes. He has only boxed 3 matches since 2011. How come he earn more then the superstars in nba, football, golf and soccer that frequent the media alot more often? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1eg4qq/eli5why_are_boxers_topping_the_list_of/ | {
"a_id": [
"c9zwjtb",
"c9zwnt1",
"c9zxii9"
],
"score": [
4,
4,
2
],
"text": [
"Think about it this way. A basketball player plays 82 games a year but revenues he generates are split among the 12-15 players on his team, coaches, and the largest share goes to the owners. The Collective Bargaining Agreement in the NBA has rules in place that say the players only receive something like 47% of all revenue brought in. So even if a basketball player plays in 82 games, the money is being split up in a lot of directions, only giving him a small portion of the revenue he brings in, even if he's LeBron James.\n\nA boxer, from my understanding, gets a large majority of the revenue brought in. He is the only 'player' on his team, although I'm sure his trainers, coaches, etc get a (relatively small) portion of the money. \n\nThe highest paid basketball players get ~$20 million a year. Mayweather got $32 million alone for his last fight a couple of weeks ago. ",
"A big part of it is the nature of the sport. Assuming a boxer has \"made it\", they are fighting around twice a year, and there's a big enough fan base that when the fight happens, the arena is sold out, and a lot of times with tickets hitting pretty hefty prices. This is completely anecdotal and I stopped following boxing, but I remember that the cheapest \"nosebleed\" ticket for a Bernard Hopkins super-fight (maybe rematch against Jermaine Taylor) was something like $300. And they're priced like that because of the demand.\n\nSo these fights are HUGE money generators, to the point where these purses get into the tens of millions of dollars. And keep in mind this is all for 1 individual (and I guess his trainers) vs an entire roster in other sports. Then when you add sponsorship, pay per view earnings (which I think is pretty unique to fight sports), and so on, this gets them pretty high up there.\n\nOne last note, I think boxing is somewhat unique in that there's a fairly lopsided pay scale compared to other sports. I think in baseball, basketball, and football, even a bench scrub is making low 6 figures, while in boxing if you're doing 4 or 6 round fights you're still only making a few thousand dollars a fight. It's when you make it to the 12 round fights and become a super star where you really explode, and there's no contract in that if you lose a fight or two, that money flow stops immediately.",
"They are getting their face punched in. Literally."
]
} | [] | [] | [
[],
[],
[]
] |
|
66oefy | why are our back muscles so relatively weak? | I understand why they aren't as strong as our legs or arms. But compared to say the abs, they're very weak. Surely stronger back muscles would lead to less damage/strain and easier lifting | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/66oefy/eli5_why_are_our_back_muscles_so_relatively_weak/ | {
"a_id": [
"dgk0g6t",
"dgk0k3o",
"dgk6niv"
],
"score": [
2,
7,
15
],
"text": [
"They're designed to hold up our abdomens, and that's about it. We're supposed to use out legs and arms for strength",
"What do you mean? My upper back is stronger than my chest and my lower back is far stronger than my abs. I can deadlift 150kg but only squat about 130kg. My back is about the strongest part of my body.\n\nI wouldn't have a chance of curling more than 25kg or so with one arm but I can do rows at like 60kg with no problem.",
"I think what you are asking is why do so many humans have back issues. I think it's because humans are not supposed to sit and lounge all day like we do so much in our society. Back in our primitive days, we did so very little sitting around that our bodies did not adapt to having the need for \"strong\" lower backs. Therefore, as time went on and as technology became a huge part of our lives, we adapted into lifestyles that allow for more lounging."
]
} | [] | [] | [
[],
[],
[]
] |
|
3arthp | why does our sense of temperature change, in regards to air and water? | For example, if I'm in a jacuzzi before it's completely warmed and it's at about 95 degrees, I'm mostly comfortable.
When I'm in a room that's 95 degrees, I feel like I'm about to freaking die. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3arthp/eli5_why_does_our_sense_of_temperature_change_in/ | {
"a_id": [
"csffprq"
],
"score": [
6
],
"text": [
"Water and air conduct heat at different rates, with water being a fantastic conductor of heat and air being an insulator for heat. Your feeling of hot/cold is dependent on how quickly the environment takes heat away from you. And whether or not you're comfortable is dependent on how much effort your body has to use to keep your body at a normal temperature.\n\nWater absorbs a lot of heat quickly and will quickly dissipate it into nearby water. A tub at 95 is close to your body temperature so it'll absorb heat. But since it's already close it wont absorb a ton of heat and your body has an easy time keeping your temperature regulated.\n\nAir will absorb the heat, but it won't move the heat quickly to the rest of the room. If the air doesn't move at all the air immediately around your body quickly reaches your body temperature and your body has to work(sweating) to lower its temperature to keep you from overheating."
]
} | [] | [] | [
[]
] |
|
5m6xo8 | how come domesticated animals such as goats need to have their hooves trimmed to prevent injury? how do wild animals solve that problem? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5m6xo8/eli5_how_come_domesticated_animals_such_as_goats/ | {
"a_id": [
"dc17y8a",
"dc1800n",
"dc1814a"
],
"score": [
2,
2,
3
],
"text": [
"Wild animals experience wear and tear from walking around over rocks and earth. Domesticated animals don't experience near this amount of exposure, thus their hooves or nails may need to be trimmed",
"The quick and easy answer is that they wear down naturally in wild conditions. Domesticated animals live vastly different lives than wild animals, different surfaces, different diets, etc.",
"i think most wild animals that have this done tend to take care of it naturally by just walking around on harder surfaces. rocks and wot not with wear the hooves down. domesticated animals tend to be kept in a field full of soft grass."
]
} | [] | [] | [
[],
[],
[]
] |
||
3vnpvg | why are conflicts going on in the world right now not a world war? and when will it become one? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3vnpvg/eli5_why_are_conflicts_going_on_in_the_world/ | {
"a_id": [
"cxp34i1",
"cxp34rz",
"cxp38bb",
"cxp4w6b",
"cxp64xv",
"cxp8w1z"
],
"score": [
19,
12,
2,
44,
5,
4
],
"text": [
"A world war is [defined](_URL_0_) as the most populous and powerful countries fighting each other. The middle east is troublesome, but not a superpower. If China and Russia jumped into the picture, then we would have a war big enough to involve most of the globe.",
"Both world war were total: it means that everything the country was doing was for feeding the war machine, it changed the living of people even in places were the conflict didn't take place.\n\nYou can argue that the current conflict with the coalition concerns many countries, but the war for the coalition isn't total, it is also quite an occidental/middle east war. World war II took place in the pacific, Asia, middle east, north Africa, America and Australia (never forget Australia and Canada) and Europe. With colonies european powers had, it expanded the areas concerned with the war with mainly India and the indochine.\n\nIs it going to become one? Weeeeell that's what ISIS wants soooo.\nIt is hard to imagine a nuclear war between the US, Europe Vs Russia Vs China, everyone needs China for everything, and a lot of countries need Energy and ressource from Russia.",
"I'm not very knowledgeable on this subject but I presume that although most of the world is involved with the ongoing conflicts, they are not \"at war\" with the countries in question. Also, most of the world needs to be directly involved with the same conflict. (e.g., WWII, involving U.S., basically ALL of Europe, Japan, China, and others.)",
"Never before has world has been in a state of peace such as this. There are almost no active wars going on now, which is unprecedented.\n\nWorld War is a hazy term, but generally speaking you'd want large nations wage active war against each other. Proxy war does not quite suffice, for example, Cold War was fought as a proxy war between US and Russia, never did the two nations troops directly clash, they merely supported different sides of various conflicts.\n\nSyria is sort of a proxy war, for example, with plenty of conflicting interests, but the ones actually doing the fighting are locals for the most part.",
"1. WW: around 17 million dead people\n2. WW: around 80 million dead people\nWar in syria: 240k dead people \nThe current conflicts are sad, but they are nothing compared to the casualties in the world wars.",
"Most of the conflicts going on right now are relatively small. Sure, you've got your hotbeds like the Middle East, Ukraine, etc, but these are small regions of the world. And most of them involve small, radicalized factions fighting for some kind of goal. The major world powers are not presently at a state of war, which would define a world war, nor have the actions of the small factions dragged in other powers through alliances and treaties, as was the case with both world wars.\n\nThe truth of the matter is, while there is a lot of conflict going on, the economy is also so heavily globalized that a world war is highly unlikely to ever happen. Sure, the US and China may not be the best of friends, yet each rely greatly on the other for economic reasons. The same is true with the Middle East: as long as the oil production remains, there is no incentive to launch a full-scale war there.\n\nAs someone else earlier mentioned, we are also living in arguably the most peaceful time in world history ever, though it may not seem like it. And much of that can be attributed to globalization: all the world powers need one another now."
]
} | [] | [] | [
[
"https://en.wikipedia.org/wiki/World_war#Later_world_wars"
],
[],
[],
[],
[],
[]
] |
||
7ra2bh | why are cryptos primarily(always?) mined using the gpu? | This specific question came to mind, but it also solidified the thought in my mind that I don't really understand how a CPU/GPU works and its primary function. Hopefully I can give some more context through some other questions I have, in turn giving more insight to where this question is stemming from.
So, why are cryptos primarily mined using the GPU, but what does that say about the CPU; why is a GPU more efficient at these computations? What specifically is GPU designed for(Image processing?)? Image processing, but what exactly does that process look like? What steps are taken on the path of processing an image? Both virtual steps and physical steps. How does that process correlate to coin mining such that it is more efficient to mine via the GPU?
Does it have to do with registers? Is a register simply a different piece of memory? just closer(easier to access) than RAM? What path would the computation take if the CPU were processing it vs if the GPU were processing it? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/7ra2bh/eli5_why_are_cryptos_primarilyalways_mined_using/ | {
"a_id": [
"dsva9kt",
"dsvhuwm"
],
"score": [
11,
2
],
"text": [
"TLDR: Cpus run your computer, and thus have to be able to do a lot of things well at the cost of speed. GPUs are mostly just process graphics, which is mostly a monotone process. As such they are built to do few things incredibly fast. \n\nCPU are masters of general logic. They can do a lot of different things very well, and as such are great at running your computer and general purpose computing. \n\nGPU's are designed to do one thing very very well: repeated calculation. Their intended purpose is processing graphics which involves a whole lot of doing the exact same calculation over and over and over. Most of graphic processing is just built on linear algebra and a whole lot of matrix multiplication. They are thus optimized to be able to calculate a lot of similar things in parallel using multiple cores. \n\nBecause cryptomining is just running a hashing function again, and again, and again, until you find an answer GPUs are a prime candidate (aside from single purpose CPUs) for mining. Their entire purpose is to calculate a lot of things fast. \n\n\n",
"CPUs and GPUs are designed differently. \n\nCPUs are designed to be very fast at carrying out a list of instructions on individual pieces of data, like adding 2 numbers together. Multicore CPUs can execute a seperate list of instructions on each CPU at the same time. GPUs are slower (especially when making choices) but they perform the same instructions on a large quantity of data at the same time. So instead of being given 2 numbers a GPU is given 2 lists of numbers and adds each pair together.\n\nIn design terms a CPU has a small number (such as 4) of very smart independent cores. A GPU has a large number (as many as 1000 depending on how you count) of very dumb cores that can't act independently - they all follow the same instructions just with their own data.\n\nAll this means that GPUs are very fast at certain repetitive and math heavy tasks. Graphics are their primary function since that requires the same calculations to be performed for millions of pixels. Tasks like mining also work well since it's performing the same math on a large set of data. Other tasks, in particular many real time or serial operations that rely on a chain of decisions are not well suited for GPUs. This is in addition to the fact that programming for GPUs (or even for multicore CPUs) tends to be more labor intensive as tasks usually cannot be done in a clear simple order, they need to be split into parallel components (so it's the difference between making a simple TODO list and requiring a manager to break out gantt charts and plan the timing of the entire thing)."
]
} | [] | [] | [
[],
[]
] |
|
4o7a9z | how do ticket buying bots actually work to buy tickets from, say, ticketmaster? | I understand the concept of how it works. I just don't understand how bots are able to navigate all of the pages necessary to complete a ticket sale and so quickly that no tickets are available by the time I log in by hand. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/4o7a9z/eli5_how_do_ticket_buying_bots_actually_work_to/ | {
"a_id": [
"d4a68pm"
],
"score": [
3
],
"text": [
"They basically execute all of the actions you do, expect the scripting eliminates all of the little delays introduced by a human. No moving the mouse to the text field, no typing in numbers one by one, etc. They're only limited by the speed of exchanging data. Pretending to be a browser is a little slower than interacting with a streamlined protocol (API), but it's still many times faster than a human actually using the browser. "
]
} | [] | [] | [
[]
] |
|
5ynzmn | what are the historical/social reasons that cause americans to tend to define their political affiliations as a fixed variable? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/5ynzmn/eli5_what_are_the_historicalsocial_reasons_that/ | {
"a_id": [
"derldib"
],
"score": [
2
],
"text": [
"In the United States, the Democratic party has for decades been the party of coastal areas and big cities, where the Republicans have been the party of rural areas and non-coastal areas.\n\nRegional affiliation rules the parties, rather than ideology, and whatever is popular in a region becomes the party platform. Party affiliation is usually based on the culture you find yourself in. The actual principles that the parties believe in change from election to election based on what these regions desire.\n\nFor example, Ronald Reagan is a Republican hero even though he created most of the national debt, because at the time the debt wasn't an issue that rural Americans cared about. Once hard times hit and they started caring about that, then balancing the budget became a conservative issue."
]
} | [] | [] | [
[]
] |
||
56sj4v | the difference between an engineer, an architect, and a carpenter. | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/56sj4v/eli5the_difference_between_an_engineer_an/ | {
"a_id": [
"d8lyevu",
"d8lyhds"
],
"score": [
2,
4
],
"text": [
"There is a lot of overlap between architects and civil engineers. But architects are more concerned with the aesthetics and spatial uses of a building, whereas engineers would focus more on physical design requirements (such as earthquake tolerance).\n\nCarpenters build using wood.",
"Architect designs the building - considering what is needed/wanted and considers the functional use of the space, how it appears to the users of the space, and how it will be constructed and maintained.\n\nEngineer - for a building will be concerned with whether the design is safe for people to inhabit taking into account all situations: snow storms, rain, earthquakes, normal and maximum weight loads, etc.\n\nA carpenter follows the design plans and creates the building (specifically a carpenter typically works with wood which is a common building material)."
]
} | [] | [] | [
[],
[]
] |
||
1vszwx | how can multiple processes on my computer be using over 100% of my cpu? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1vszwx/eli5_how_can_multiple_processes_on_my_computer_be/ | {
"a_id": [
"cevhqz1"
],
"score": [
2
],
"text": [
"if you have multiple cores, you can have multiple cpus > 100% available."
]
} | [] | [] | [
[]
] |
||
3ivptx | why are there only 16.8 million of color combinations in most rgb products? | For instance in an RGB keyboard, mouse, or monitor, why can it *only* make 16.8 million colors? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/3ivptx/eli5_why_are_there_only_168_million_of_color/ | {
"a_id": [
"cuk1dzj",
"cuk1evr",
"cuk1gyv"
],
"score": [
14,
7,
3
],
"text": [
"An RGB color has 3 number: a red component, a green component and a blue component. Each of these numbers is encoded in1 byte (this is a standard). 1 byte has a range of 0 to 255, which is 256 numbers. So if you have 3 numbers and each can have one of 256 possible numbers then your total possibilities are 256^3 which is 16.8 million.",
"\"Only\"? How many more colors do you know of??\n\nAnywhoo, RGB colors are stored as 3 8-bit channels; red, green, and blue. An 8-bit binary number has 256 possible combinations (2^8 = 256). Since the final color is a combination of those 3 channels, you have 256x256x256 = ~16.8 million.",
"Because 256\\*256\\*256 = ~16.8 million. \n\nIn the red/green/blue (RGB) format you're talking about the amount of red, green and blue respectively are stored as a 1 byte integer. A 1 byte integer can store 0-255. (The same way a 2 digit number can only store 0-99, a 1 byte integer can only be 0-255)\n\nFor each red value you can have any arbitrary green and blue colours, so each red value can have any given green value. That means 256*256 combinations. Similarly you have another set of 256 variations for each value of blue giving 256^3."
]
} | [] | [] | [
[],
[],
[]
] |
|
1829e2 | no win no fee lawyers. what's the catch? | Surely they can't be that confident they'll win or afford to serve just to go to waste | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1829e2/eli5_no_win_no_fee_lawyers_whats_the_catch/ | {
"a_id": [
"c8ayrfl",
"c8ayycw",
"c8azr7y"
],
"score": [
2,
2,
3
],
"text": [
"Depends, theres 3 main ways, most use a combination of these\n1.Theres a first time consultation fee\n\n2. They will take most of the money you win (so if the court gives you $10,00 the lawyer might take $8,00 of that),\n\n3.They will not take all cases, theres 3 factors at play here\n a. How much they think you will win\n b. How likely you are to win\n c. How long it will take",
"If the case is won, the lawyer gets a larger fee than normal I believe... And if its lost, he's out all the costs. Both parties are kinda gambling.",
"It's all about expected value, and the laywers make that work in their favour by taking a big portion of the winnings. \n\nLet's say the lawyer has 10 cases this month, each with a potential settlement of $1000, and the lawyer takes half of the settlement if they win. Assuming they lose most cases (say 80%), the lawyer will still get $1,000 (2 cases x $1,000 per case x 50% lawyer fee) in earnings this month.\n\nIf that's enough to cover the costs, and their lifestyle, then they are good to go. \n\n"
]
} | [] | [] | [
[],
[],
[]
] |
|
f03axn | why is it easier to read something when i’m the one holding it | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/f03axn/eli5_why_is_it_easier_to_read_something_when_im/ | {
"a_id": [
"fgr96wk",
"fgrbf6k",
"fgrc9gp",
"fgrigwk",
"fgrl4as",
"fgrmt5k",
"fgrmtyb",
"fgrnfkj",
"fgrq922",
"fgrsos4",
"fgru8vs",
"fgruzvc"
],
"score": [
168,
2,
4799,
24,
6,
3,
31,
822,
3,
6,
4,
2
],
"text": [
"The brain is very good at adapting to different circumstances to function optimally.\n\nPart of this adaptation is syncing movements of the eyes with subtle movements of the hands. So even though the image is moving it appears still, allowing you to read.\n\nWhen you aren't holding it, it becomes more difficult for the eyes to sync with the movement of the page so the words appear blurry.",
"You may have vision issues, but as bigjoe said, your brain compensates better when you hold objects.\n\nTry an experiment. Have him set it down and try to read it..you hold it and try to read it then set it down by you and try to read it.\nWhen someone else is holding it, the position is likey suboptimal.",
"[Proprioception](_URL_0_)\n\nBasically, your brain knows where the parts of your body are, even when it can't see them. There are special nerves just for this function. That's why you can close your eyes and move your arms around (or even let someone else move them) and still know where your hands are.\n\nThis still helps even when your eyes are open. Your brain is aware of the tiny movements your arms and hands are making and can correct for them much faster than they can for your friend's movements, which have to be processed visually.",
"brain stabilizes with your hand movements... \n\nIf you've ever smoked, you'll notice the same thing when someone else tries to light your cigarette...",
"Back when research was done through microfiche slides it was super frustrating to have all the data right there on the screen, but only the person moving the controller able to interpret any of it.",
"Your body does a helluva lot better of a job processing minuscule movements when you’re holding something, since to a certain extent, your body can detect those minuscule movements and adapt to it better.\n\nIt’s called proprioception, which is the body’s ability to tell where it’s body parts are. This takes into account even the smallest of changes, meaning it can better wrap its head around its own tiny little movements as opposed to someone else’s.",
"Your eyes subconsciously coordinate with the movements of your hands. They can't do that if they don't get the sensor feedback from your fingers.",
"You want an actual ELI5 answer? Your eyes can't talk to the other person's hands to find out where they are holding the book.",
"Follow up question, why can I smell something so much better when I hold it in my hands vs someone else's hands? I can usually only smell their hands",
"It’s like driving and making a sharp turn. You feel it less jarring because you know what’s coming up and you’re body prepares for it by tensing certain muscles. The passengers don’t know this, so they react to it later, which causes discomfort etc.",
"Because even if you don't see or realise it, everyone's hands are not stable and constantly shaking. When you're the one holding the thing, your brain is aware of all your little movements and can compensate.",
"In short, you manage the optimum distance so your eyes can focus and the amount of time you actually have to look at it for processing."
]
} | [] | [] | [
[],
[],
[
"https://en.wikipedia.org/wiki/Proprioception"
],
[],
[],
[],
[],
[],
[],
[],
[],
[]
] |
||
20k6ho | how does a master key work? wouldn't the key ridges be the same as a different key that isn't a master? | Say I live in a dorm and the Janitor has a master key. Since him and I both have a key that opens my door couldn't I open another persons door with my key since the master key and my key have the same ridges? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/20k6ho/eli5_how_does_a_master_key_work_wouldnt_the_key/ | {
"a_id": [
"cg416ri"
],
"score": [
5
],
"text": [
"A lock has pins inside it. Each pin is actually two, and the ridges in the right key make the place where they meet line up with the place where the cylinder (the part that turns) meets the body of the lock, so it can turn. Many locks with master keys actually have pins in three parts, so there are two correct heights for each pin. Most such systems have the master key use the part that makes you raise the pin higher, so someone with a more common key cannot file theirs down the get a master key."
]
} | [] | [] | [
[]
] |
|
3a5k08 | what's happening when i get alcohol, lemon juice, salt etc in a wound and it stings? | What does it hurt so bad | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3a5k08/eli5_whats_happening_when_i_get_alcohol_lemon/ | {
"a_id": [
"cs9hp0w"
],
"score": [
6
],
"text": [
"Each has a different mechanism of action on cells, including nerve cells. And here, I'm going to assume the wound is open exposing dermal layers and perhaps nerve endings. The very reasons why these are painful make them excellent preservatives of food.\n\nSalt is isotonic, meaning that it will constrict cells as fluid rushes out to maintain a new equilibrium via osmotic pressure. Constriction on a scale the size of a gash is extremely painful. A side benefit is that salt on a wound, while extremely painful can have antimicrobial properties by making the environment unfavorable for bacteria. This is why food is preserved in salt since ancient times. Also as an interesting side-note, when battles were fought near the sea, the wounded would be instructed to swim in the ocean to \"cleanse\" the wounds. As excruciating as that sounds, it saved many lives.\n\nLemon juice is, of course, acidic. Hydrogen ions swing the pH of the surrounding environment much lower and more acidic [H+]. Citric acid is a weak acid, but an excellent chelating agent, meaning that it readily binds to metals. Iron from the blood is drawn to the acid, rupturing blood cells and the like. The primary result is irritation and swelling as the immune system attempts to block excess acid from entering the body and continuing the reaction. This reaction is also very painful. But because of this, citric acid is used as a food preservative.\n\nAlcohol has essentially the same affect, though less so than lemon juice. Ethyl alcohol has two carbons and a hydroxyl group. A reaction occurs that separates < some > of the hydroxyl groups, creating ethane, hydroxyl ions, etc and making the environment basic [OH+]. For the same reasons stated above this is very painful. But a side benefit is that the solution can disinfect by killing bacteria in and around the wound because molecular ethyl alcohol will denature proteins and dissolve lipids due to its solvent properties. A solution of 70% ethyl alcohol in purified water is the preferred method of sanitizing lab spaces. Alcohol is also used in preserving food for this very reason.\n\n/source: biochemist"
]
} | [] | [] | [
[]
] |
|
ky19u | why is everyone cautions about salmonella, but sushi is okay? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/ky19u/eli5_why_is_everyone_cautions_about_salmonella/ | {
"a_id": [
"c2o5xza",
"c2o6yar",
"c2o70i0",
"c2obb37",
"c2o5xza",
"c2o6yar",
"c2o70i0",
"c2obb37"
],
"score": [
15,
5,
8,
2,
15,
5,
8,
2
],
"text": [
"Raw fish in sushi, called *sashimi*, can indeed contain bacteria or parasites. To get rid of parasites, some countries have laws saying that you must freeze the fish at [253 K](_URL_0_) for many hours. Many parasites freeze to death at such low temperatures. \n\nHowever, other foods, like ground beef, often do not have such laws about freezing, so there can be bacteria or parasites that survive.",
"I got salmonella from eating sushi, and I still eat it. As long as you don't go to a vacant chinese buffet at night (like I did whoops), I don't think there's much of a risk.",
"Because sushi is FUCKING DELICIOUS",
"Sashimi is supposed to be made using fish caught in the wild. Free swimming fish have less of a chance to catch parasites. Freezing them on transport may kill off some of the bacteria/parasites that could be harmful to humans, but it's mostly to prevent the overgrowth of them.\n\nIn farmed fish diseases and parasite can spread easier. \n\nWhen you hear about diseases in certain foods, and that you should be aware of them, it doesn't necessarily mean it's coming from the food, or it's natural environment, (think salmonella and spinach) but most likely the processing center that's propagating it from improper sanitary conditions. Having one or two items contaminated from improper handling could cause a whole day, weeks, or months, worth of food being affected from a contaminated processing center.\n\n**ELI5:** When fish are caught in the ocean they get taken to factories to be cut up to be made into food. If the person, or machines, cutting the fish aren't cleaned properly you could get sick. Sometimes people don't wash their hands and could get others sick if the cut the food without gloves. \n\nSo always wash your hands!\n\n",
"Raw fish in sushi, called *sashimi*, can indeed contain bacteria or parasites. To get rid of parasites, some countries have laws saying that you must freeze the fish at [253 K](_URL_0_) for many hours. Many parasites freeze to death at such low temperatures. \n\nHowever, other foods, like ground beef, often do not have such laws about freezing, so there can be bacteria or parasites that survive.",
"I got salmonella from eating sushi, and I still eat it. As long as you don't go to a vacant chinese buffet at night (like I did whoops), I don't think there's much of a risk.",
"Because sushi is FUCKING DELICIOUS",
"Sashimi is supposed to be made using fish caught in the wild. Free swimming fish have less of a chance to catch parasites. Freezing them on transport may kill off some of the bacteria/parasites that could be harmful to humans, but it's mostly to prevent the overgrowth of them.\n\nIn farmed fish diseases and parasite can spread easier. \n\nWhen you hear about diseases in certain foods, and that you should be aware of them, it doesn't necessarily mean it's coming from the food, or it's natural environment, (think salmonella and spinach) but most likely the processing center that's propagating it from improper sanitary conditions. Having one or two items contaminated from improper handling could cause a whole day, weeks, or months, worth of food being affected from a contaminated processing center.\n\n**ELI5:** When fish are caught in the ocean they get taken to factories to be cut up to be made into food. If the person, or machines, cutting the fish aren't cleaned properly you could get sick. Sometimes people don't wash their hands and could get others sick if the cut the food without gloves. \n\nSo always wash your hands!\n\n"
]
} | [] | [] | [
[
"http://www.wolframalpha.com/input/?i=253+K"
],
[],
[],
[],
[
"http://www.wolframalpha.com/input/?i=253+K"
],
[],
[],
[]
] |
||
3gb7ef | could we have another plague outbreak? | With the recent news of people in colorado getting the Plague, could we have another outbreak, like the one that wiped out a lot of the population? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/3gb7ef/eli5could_we_have_another_plague_outbreak/ | {
"a_id": [
"ctwina1"
],
"score": [
2
],
"text": [
"Not like before, no. \n\nModern sanitation as well as advances in how we handle the sick and the dying mean that it might try to start but would never advance to the levels seen in the middle ages. We were still throwing our sewage in the streets in those days. "
]
} | [] | [] | [
[]
] |
|
7b5z6k | how do fish and other aquatic animals deal with the change in pressure from going from shallow water into the deeper parts? | I know most species kind to stay around a certain depth but some species go from a miles down to near the surface. The pressure difference must be insane so how do they compensate for that | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/7b5z6k/eli5_how_do_fish_and_other_aquatic_animals_deal/ | {
"a_id": [
"dpfg2qe",
"dpfj7b5"
],
"score": [
9,
3
],
"text": [
"Because fish don't have air inside them - they have water, due to having no lungs. Water isn't compressible (well, not much), and as a result they don't get compressed at significant depths. \n\nWhales deal with things differently. They allow the air in their lungs (and other cavities) essentially \"collapse\" so that their body adapts as it dives. They can go pretty deep, but not as deep as fish.",
"It is not as much of a problem as you might think. Human scuba divers can reach depths of 1000 feet, which is about 30x normal pressure. It is very dangerous and requires a lot of preparation, but their bodies are just fine at that pressure. The real danger is keeping the air their breath safe. At that depth, anything more than about 5% oxygen is toxic, and the air is so thick the effort you expanding your lungs to draw it in can exceed the energy you get from its oxygen...you literally can suffocate from breathing too hard. There are proposed liquid breathing solutions, like those in the move *The Abyss*, that would allow for much deeper diving, but the technology is not there yet.\n\nMost aquatic animals don't vary their depth by that much. Once you get beyond a few thousand feet in depth, the oxygen content in seawater drops to the point only animals specially adapted to it can survive. Air-breathing animals that dive that deep can hold their breath for extended periods of time, which avoid many of the issues divers face. That also tend to have special adaptations, like collapsable lungs, that help them survive the high pressures. Beaked whales are the deepest divers, and can reach up to 10,000 feet.\n\n"
]
} | [] | [] | [
[],
[]
] |
|
2l3nik | how do professional coaches find elite athletes? | I'm sure there are numerous examples but how did they pick Tom Brady over all the others? Don't get caught up on the player(s) the real question is:
Hundreds of players who play the same position show up to a combine (or the such) how exactly are the coaches able to compare them to one another? Especially those who never played for winning or high profile programs? Is it more science or luck? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2l3nik/eli5_how_do_professional_coaches_find_elite/ | {
"a_id": [
"clr5pgy"
],
"score": [
2
],
"text": [
"There is definitely a huge component of luck involved. \n\nThe short and far too simple answer is scouts look at two things: measurables and intangibles.\n\nMeasurables are straightforward. How tall is a guy? How fast can he run and jump? Etc. Etc.\n\nIntangibles are things you can't measure but have a huge impact in a game. This is hard to explain but the way scout determine this is by watching tape of a player in games. Maybe he does something that you can't put into some sort of measurable metric. For example how does Tom Brady play better when there is more pressure on him when lots of other players can't handle it? Why do Ronaldo and Messi just flat out outplayed everyone else on the field?\n\nScouting is an art that teams try to make a science. Some guys are easy to spot at being good (e.g. Peyton Manning or Andrew Luck). Some guys most teams let slip through the cracks (Joe Montana was a 4th round pick. I believe Terrell Davis was a 7th round pick). Later round picks are the guys that have that something you just can't measure. Call it heart, drive, guts, whatever."
]
} | [] | [] | [
[]
] |
|
79nsng | what happens to dead cells | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/79nsng/eli5_what_happens_to_dead_cells/ | {
"a_id": [
"dp3d7ii"
],
"score": [
2
],
"text": [
"Your body has a waste disposal system. It grabs stuff that shouldn't be there and expels it with the rest of the waste. Ever wonder why specific bodily waste is brown? That's dead blood cells. \n\n"
]
} | [] | [] | [
[]
] |
||
6yvr2t | what happens if you are payed counterfeit money for a good or service? | For instance, lets say you are payed $500 dollars to fix a fridge or something, but when you go to deposit money, you find it is counterfeit cash. What do you do with the counterfeit cash, and is there anyway to get compensation? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/6yvr2t/eli5_what_happens_if_you_are_payed_counterfeit/ | {
"a_id": [
"dmqhrkn"
],
"score": [
2
],
"text": [
"In Denmark, they will spot the counterfeit money, and take it. Police will be called and you will have to give them a statement. If you really dont have any idea you had the illegal cash, you will simply loose the money, and once you told them who gave it to you, they will go there next ect. 95% chance nothing will happend to you, as long as you are honest and forthcomming."
]
} | [] | [] | [
[]
] |
|
saqnv | how the five primary senses work | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/saqnv/eli5_how_the_five_primary_senses_work/ | {
"a_id": [
"c4ci4gc"
],
"score": [
5
],
"text": [
"**Touch** \nYour body is covered in things called nerves. There are nerves on your skin, in your mouth, in your nose, all over the place. Each nerve has a special job. Some are for noticing heat or cold, wet or dry, rough or smooth or for noticing pain. When a nerve detects the thing it is looking for, it sends a message to the brain. The brain knows which nerve is where and uses the messages to build up a picture of what is happening to you. \n\n**Taste** \nThis one works pretty much like touch does except the nerves are called 'taste buds' and are specialised for detecting stuff like sweet and sour as well as all the other stuff. \n\n**Hearing** \nYou know how a breeze makes the windchimes knock about to make a noise? Your ears work sort of like that. There's a little thing in each ear that rattles on another little thing depending on how the air around you is vibrating. The pattern of the vibration then gets sent to your brain so that you can figure out what it means. When someone talks, it makes a certain kind of vibration in the air which your ear can pick up and your brain can turn into words. \n\n**Sight** \nYour eyes work kind of like cameras. There's a bunch of sensors in the back of your eye (the 'retina') for detecting light and there's a lens at the front for focussing the light. Light passes into your eye through the lens and onto the retina where it gets picked up and sent to the brain which figures out what kind of picture it is looking at and what it means. \n\n**Smell** \nThis is kind of like touch or taste except it uses a special kind of neuron instead of nerves or taste buds. Smells travel in the air in the form of tiny particles*. There's a patch of little neuron sensors inside your nose which are good at intercepting these particles and figuring out what they are. The information is sent to the brain which uses the combination of particles to figure out what you're smelling. \n\n*NB not technically the right word for them"
]
} | [] | [] | [
[]
] |
||
duql2u | why do humans pack bond with so many species/things | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/duql2u/eli5_why_do_humans_pack_bond_with_so_many/ | {
"a_id": [
"f7ay7li"
],
"score": [
2
],
"text": [
"Among mammals at least, humans are the most prosocial species we've ever discovered. No other mammal lives in groups as large as us, and maintains relationships with as many unique individuals as us. Furthermore no other mammal practices sharing and cooperative behavior on as significant a scale as us. We evolved to be so cooperative with one another that we developed spoken language as a way to negotiate ever more complex forms of cooperation and organization with one another. Imagine how difficult it would be to try to live with other people (in a house, in a neighborhood, in a city, in a country) if all you could do to communicate was grunt, cry, growl, whine, and make simple hand gestures at them. That's what other mammals' lives are like.\n\nSo eager are we to enter into cooperative arrangements that we sometimes extend past our own species and seek to cooperate with animals. Cats to catch our pests, cattle to give us milk, dogs to, well, be dogs. \n\nAs for *why*? Who knows. Evolutionary biologists and evolutionary *psychologists* will argue about this endlessly, and there's scant evidence to support any of it. For whatever reason, humans evolved to be unusually pro-social and willing to cooperate. We evolved the most acute senses to detect intentions from other humans (and indeed from other animals). Our very strategy for survival is so intimately tied up in cooperating with others that we had no option but to evolve these senses. Humans virtually never live alone in the wild, completely isolated and totally fending for themselves. It's nearly impossible to do. We *need* other humans in a way that few animals do. Many animals are capable of living alone in the wild, and do all the time, even ones that typically live in groups. Lone individuals can and do leave the group all the time and go off to live a solitary lifestyle. For humans, this means almost certain death.\n\nAnd because we're so prone to trying to read other people's intentions, we sometimes get over-eager. Sometimes we detect intentionality that isn't actually there, for example in inanimate objects. Lots of animals do this to some extent, it's smarter to be *too* suspicious than insufficiently suspicious. If you're suspicious of something and you're wrong and it turns out to be harmless, then you're fine, no big deal. But if you're *not* suspicious of something and you're wrong and it turns out to be dangerous, you're fucked. Humans just do it a lot. Because of this, sometimes we read intentions even into objects or things, and develop \"cooperative\" relationships even with things that aren't animals.\n\nTL;DR: Humans are so eager to bond with each other that we developed the capacity to bond with non-humans as well."
]
} | [] | [] | [
[]
] |
||
1b1qfe | where do movies get newborn babies? | I get that they're usually just slightly older babies but sometimes it seems that they're fresh out of the womb. Surely they can't just bring one straight from the hospital when they're born. | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1b1qfe/eli5where_do_movies_get_newborn_babies/ | {
"a_id": [
"c92rgl3",
"c92rzq8",
"c92sr4d",
"c92uj5h",
"c92v1wk",
"c92w53b",
"c92waek",
"c92we1k",
"c92wtr1",
"c92x46k",
"c92x4eq",
"c92xax7",
"c92xi30",
"c92xidq",
"c92ybuf",
"c92yrkz",
"c92zdma",
"c92zi71",
"c9306d4",
"c9312jz",
"c93133x",
"c9314sf",
"c931pci",
"c93205k",
"c9322my",
"c934gxc",
"c936aba",
"c936kg2",
"c936qvz",
"c938nsu",
"c93a55w",
"c93f9j6"
],
"score": [
1678,
21,
132,
83,
5,
37,
27,
36,
4,
3,
13,
3,
8,
28,
5,
4,
5,
5,
4,
2,
3,
5,
2,
3,
16,
4,
3,
3,
2,
2,
2,
2
],
"text": [
"They're pretty much all several weeks old. Because if nothing else - to be in a film you need a bunch of paperwork filled out and filed, and that takes a couple of weeks to do. Also, newborn babies (ie 48 hours or less) are ugly as hell. Three week old babies are cute.\n\nBut there's services in Hollywoodland wherein pregnant women register themselves and their due date, and when it comes time to shoot the baby scene the movie company calls up the baby service and says \"Yeah, I need a black male - how many you got for next Thursday?\" and the Service company makes some calls and comes up with a number - 3, 5, 10, whatever. That many black male babies of the apropriate 3-6 week age. So those mothers drag the kids over next Thursday (assuming the kid isn't sick, or whatever) and they shoot the scene with whichever one is cooperating the most with being covered in jelly[1] and shoved under hot bright lights.\n\nAnd there's your \"birth\" scene. A jelly covered confused child who is hot and blind.\n\n\n[1]It's not actually jelly, but probably dyed petrolum gel or some other similar fluid. You get the idea - something sticky looking that's red.",
"Sometimes, as SecondTalon says, they're real babies, but sometimes they're animatronic models.",
"THIS is why I love this sub. Weird, small stuff like this. I know I have wondered this while watching movies, but the thought never sticks with me long enough to search for the answer. Thanks for asking the question.",
"Or better question: How do actresses in movies give birth to 8-week-old babies?",
"Why is this eli5? Shouldn't this just be a question for /askreddit ? ",
"During pre-production, they encourage the interns to \"network.\"\n\nActually, they just put out casting calls. I saw one once for a union or non-union Hispanic baby. I want to know how a newborn gets into SAG.",
"_URL_0_\n\nThat link goes a little further. If you have twins or triplets you can make $125 as a day rate and $700 for a bump. \n\nIn California (where i reside) the age for babies to work is 15 days with a doctors note and a work permit but only for a total of 20 minutes. They are allowed on set for a total of 2 hrs a day. Other states there is no requirement. ",
"Interesting situation I heard in the Knocked Up commentary. They wanted to shoot a live birth but the baby would have to be a Screen Actors Guild member before time of the shooting so they had to use a previously born baby for that reason...previously born baby. Does that sound weird?",
"I remember from the movie \"Do The Right Thing\", they pulled one straight out of a vagina. Seems like the natural place to find one.",
"Maybe you should just ask your parents... No? Okay, well uh... You see... When two actors in a movie love each other very much, they contact the movie stork, who then brings them a baby actor. I don't know. Look, I am gonna level with you kid. The truth is two people sex and a baby pops out. That's just how it is done. Okay go eat some cookies ",
"I guess another question to follow up is:\n\nHow do they make the babies cry?",
"I have a friend with identical twins and they did this, the benefits being you had 2 chances of getting a happy baby for the shot.",
"Isn't this more /r/answers material?",
"When a mommy movie and a daddy movie love each other very much...",
"From parents who want cash",
"Did anyone else think one of the newborn babies in \"What to Expect When You're Expecting\" looked like it was about 3 months old?",
"They keep a bunch of pregnant chicks on retainer for the eventual shoot date.",
"*Children of Men* actually used a CGI newborn baby.",
"They get them from vaginas mostly. ",
"Dumpsters primarily, waif homes as well.",
"They hire teams of hobos to steal them.",
"Don' they usually go for twins as well because young children can only be under that sort of intense lighting for a limited period of time?",
"I thought you meant where all the newborns are spawning from to ruin a movie. ",
"You really needed someone to simplify this for you?",
"When a mommy movie and a daddy movie love each other very much...",
"Often they'll use babies who were born premature, because they have to be a minimum age, and when premie babies hit that age they'll look like a normal \"to-term\" baby who was just born.\n\nAlso as someone else mentioned, the stuff all over them is jelly and cream cheese because it's illegal to put makeup on babies (but weirdly, food is totally fine).",
"Even better, where did Nirvana get that baby?",
"Producer here. Most babies in film/TV are months old, but if you see a newborn, it's almost always fake.",
"first you get the money, then you get the power, then you get sugar...ZZzzz",
"I thought they used rubber ones where if you give it a small, hard to notice shake the material bounces around and the baby looks alive.",
"When a mommy extra loves a daddy extra VERY MUCH..",
"Thank you for this OP. Wondered that for a long time. Like, who are these mothers pimping out their newborns for cash?"
]
} | [] | [] | [
[],
[],
[],
[],
[],
[],
[
"http://www.slate.com/articles/news_and_politics/explainer/2007/06/where_do_hollywood_babies_come_from.html"
],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[],
[]
] |
|
1vdjnb | how does investing in a startup work? and how do you make a profit as an investor? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/1vdjnb/eli5_how_does_investing_in_a_startup_work_and_how/ | {
"a_id": [
"cer5szi",
"cer5yo4"
],
"score": [
3,
4
],
"text": [
"Same as investing anywhere else, you give them money so they can do business.\n\nThe difference is that you are not investing in a proven company but one that may or may not succeed.\n\nYou are typically given a share of ownership in the company (say 10%). 10% ownership means that you have the legal right to 10% of the company's value/profits. Once the company goes public your ownership will be converted in shares (stock market). You can sell those shares for profit, or hang on and wait for more.",
"It just depends on the deal you make with the business you are investing in. \n\nYou could, for example, invest some start up money, and buy a share in the business. you will then make what ever % you decided on of the profits the business makes. So, for example, you invest $10,000 and own 40% of the business and will earn 40% of all their profits. \n\nYou could also have also have a deal where you lend them $10,000 and they have to pay it back to you + interest. So you make profit on whatever interest rate you decide on. "
]
} | [] | [] | [
[],
[]
] |
||
2uv093 | in films, a syringe wielding character will often inject his victim wherever he manages to jab the needle. depending on what chemical was being injected and where it ended up, what might be the effect or lack thereof? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/2uv093/eli5in_films_a_syringe_wielding_character_will/ | {
"a_id": [
"cobwte7",
"coca6pp"
],
"score": [
6,
2
],
"text": [
"[](/twinurse)This is a fairly broad question with a lot of variables to take into account. In general, though, if you're just stabbing wherever and pushing the plunger, what you are doing is known as an **intramuscular** injection. Basically the drug is being deposited into the soft tissue, where it will gradually be absorbed by the surrounding capillaries and blood vessels. What this means is whatever you're injecting is probably going to take a while because this is not a quick process. Other side effects include swelling, chance of infection, and pain at site of injection.\n\nIf you want a drug to have a fast reaction, you want intravenous or intrarterial injection, meaning that it is going directly into the blood stream. This means actually hitting a blood vessel, which when doing blindly is pretty much sheer luck. Most of the vessels near the surface aren't more than a centimeter in diameter, which means its very easy for a 'straight down' jab to go straight through the vein.",
"Depends on location, depends on the injection.\n\nAlready /u/CommissarAJ/ pointed out the importance of location. Intravenous injections (hitting a vein) can get the drug to spread through the body in under 30 seconds, with actual speed depending on blood flow. Intramuscular injections take more time, depending on where you hit and what you are doing, your blood flow, and other factors. An EpiPen is an intramuscular injection that grants full body relief within about two minutes, although full effect takes more time.\n\nOther aspects of location matter. An injection into the eyeball or piercing through a nerve bundle is going to be radically different than a clean injection into soft tissue or a shallow piercing of the skin around the skull.\n\nGetting back to the crazy person in the movie:\n\nIn all cases, running around with an exposed needle is going to increase the risk of infection at the injection site. Medical professionals use sterile needles that are \nopened immediately before use to minimize the risk of contamination.\n\nAfter that, it depends on what is in the syringe, how much is injected, and where it hits.\n\nSome toxins are quickly fatal even if delivered into muscle. A few grams of cyanide will cause some quickly-spreading cell death, but if they only get 1-2 milligrams into the person's hand or foot the person may survive quite easily. The most lethal toxin known, botulinum toxin, could be fatal with just a scratch if you get enough of the chemical in place. Toxins that cause muscle paralysis could shut down the heart, or they could just paralyze the muscle locally around the injection site, all depending on the details.\n\nIf the syringe contained the same drugs used on lab rats to cause heart attacks, strokes, and other conditions, then enough of the drug could likely cause the same effect in a human if the dose is large enough. \n\nOther chemicals could be hugely destructive if not lethal. If the syringe were loaded with sulfuric acid the attacker could do severe damage just by spraying the contents on the skin or the eyes/face. Injecting sulfuric acid inside the muscle could cause the loss of a limb if that is where they hit, or cause extensive organ damage if the attacker were to reach the chest cavity. \n\nStill other chemicals could give long-term problems. In the 1980s there were quite a few crazies who stabbed people with HIV-infected needles. In that situation it is not immediately fatal but the risk of infection is high. There are many cancer-causing compounds and infectious diseases that would not be immediately fatal but terrible in the long term.\n\nToward the lesser end of the spectrum, if it had the chemicals that cause things like migraine headaches, the most you can expect is a splitting headache for a few hours.\n\nAnd on the farthest end, if the syringe contained saline solution the effect would be minimal. Saline solution is used to flush out IV lines and in placebo injections. The person's body would be like \"thanks for the drink of water, I appreciate it.\""
]
} | [] | [] | [
[],
[]
] |
||
cardpd | how would streaming video games increase input lag/not be ideal? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/cardpd/eli5_how_would_streaming_video_games_increase/ | {
"a_id": [
"etakapp",
"etal14x"
],
"score": [
5,
5
],
"text": [
"No, streaming a game doesn't load the game data onto your RAM. The game is running on the server's RAM, and the only thing being sent to you is picture and sound data so you can see and hear the game that's running on the server. One of the main points of game streaming is that you can run powerful games using a machine that doesn't have enough RAM (and other resources) to run those games itself.\n\nInput data (when you press a button on your controller, speak into a microphone, or use other input methods) is sent through the internet to the server.\n\nBasically it's the same as playing a traditional game on a home console, except the cord from the controller to the console and the cord from the console to the TV are both hundreds of miles long. And you don't own the console.",
" > a service like Xbox Game Pass or PlayStation Now\n\nYou're conflating two different types of service.\n\nGame Pass (and I believe certain games on PS Now) is a subscription service that allows you to download the games onto your hard drive. You then play them locally just like you had bought the game yourself and downloaded it or had installed it from a disc.\n\nPS Now (and Stadia, Project Xcloud, and Geforce Now) is a different beast. With these services, the game is *not* being run on your own native hardware. It's being run on a computer/console in some datacenter in another city. All your hardware is doing is receiving your inputs, sending them to the datacenter, then receiving a video stream of what the computer/console in that datacenter is outputting.\n\nThat's why there's input lag. There is just inherently a delay in information being passed back and forth across the internet. The video stream takes time to get from the datacenter to you, so what you're seeing on stream is X milliseconds behind when it was rendered on the hardware in the datacenter. You then react and press a button or move the analog stick, etc. That input has to travel across the internet to the datacenter. The hardware at the datacenter parses your input, renders the movement of your character or your attack or your dodge or whatever you did, and sends it back to you in the video stream."
]
} | [] | [] | [
[],
[]
] |
||
313pht | what's the difference in pain from "feeling the burn" and actual muscle injury? | As I know, lactic acid causes the pain you feel the day after exercising (which may be proven wrong soon, but that's besides the point). How can one tell the difference between this normal pain and injury? | explainlikeimfive | http://www.reddit.com/r/explainlikeimfive/comments/313pht/eli5_whats_the_difference_in_pain_from_feeling/ | {
"a_id": [
"cpy5hg8",
"cpy5uw0"
],
"score": [
4,
2
],
"text": [
"\"Feeling the burn\" is caused by a buildup of lactic acid on your muscles from you breaking down the contractile proteins that make up your muscle fibers. It it generally a feeling of muscle weakness and tenderness, and is often accompanied by Delayed Onset Muscle Soreness (DOMS), which is soreness that begins roughly 24 hours after you perform an exercise that your muscles aren't used to. All of these should be more benign pain and muscle tenderness.\n\nBut any kind of sharp, acute pain is a sign of actual muscle/connective tissue injury, and should NOT be worked through. The person should stop immediately, apply ice ASAP, and possibly go to a doctor if it's real bad.",
"I've been body building for about 13 years and the advice I always give is \"you'll know when you feel it\". You know right away the difference between pain, and PAIN. An injury is usually sharp and sudden onset. You just know the difference if it happens trust me."
]
} | [] | [] | [
[],
[]
] |
|
cvd65i | how does food change color as it passes through your digestive system? | explainlikeimfive | https://www.reddit.com/r/explainlikeimfive/comments/cvd65i/eli5_how_does_food_change_color_as_it_passes/ | {
"a_id": [
"ey3xdzx"
],
"score": [
5
],
"text": [
"Your body adds bile to the food as it's being broken down. Bile is a digestive juice that is dark green. It colors everything the same color. As the food travels through your digestive tract, most of it is absorbed, but a lot of the bile remains. It gets broken down by bacteria etc to become a brown color."
]
} | [] | [] | [
[]
] |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.