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kycf6b
|
Why does digital storage always have the same values eg. 32gb, 64gb, 128gb, 256gb etc. and why do they double every time they go up in size? Is this a limitation or just a standard?
|
Technology
|
explainlikeimfive
|
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"As you probably know digital computers and storage are implemented using binary logic circuitry and this makes it convenient to work with numbers that are powers of two. In the case of storage, adding 1 bit to the range of your addressable storage also doubles the storage size. It is probably also convenient for the circuit layout to simply widen or mirror in a symmetric way (two paths instead of one, two blocks instead of one) existing structures rather than create new ad-hoc structures to deal with odd amounts of storage... EDIT: I completely missed that this is an ELI5. Ignore.",
"Read the other answers about powers of two. But with flash technology today there’s no need to stay with those standard sizes apart from tradition. The storage has to have spare capacity to deal with defects and failures so a 1GiB drive has slightly more storage than that internally. With SSDs you can get sizes like 200GB, 240GB and 256GB. Spinning disks have had sizes like this for even longer. Even the early floppy disks were multiples of 360 or 400kiB. So, tradition, and having a common set of sizes for all manufacturers makes it easy for consumers to compare value.",
"Lots of great answers, but to go even more for kids, let's say you have 8 light switches. This means you can count from 0 to 8 pretty easy. But computers are super good at adding. What if instead of each being worth one, we make them worth 1, 2, 4, 8, 16, 32, 64, and 128? Now by flipping those 8 light switches on and off I can represent any number between 0 and 255. (Remember the original Zelda game out at 255 rupees? Yes, I'm old...) So the next step is obviously to add another light switch, but we don't have to start at the beginning. The next switch can be worth 256 so now I can represent any number between 0 and 511, the next switch takes me to 1023, and the one after that will take you to 2047. We'll keep adding more and more switches until we can store all the cat pictures...",
"It's because it's based on multiples of two: 2,4,8,16,32... (base 2 mathematics) instead of multiples of 10, which is our standard human number system (base 10 mathematics). Computers use base 2 mathematics essentially because of binary code (where everything is a 1 or a 0). There's a ton more I could get into such as exponents etc, but that should suffice for a 5 year old.",
"In addition to all the other answers I’d just like to point out that this is not always the case. For example in graphics cards it’s quite common to see 3 or 6GiB or 12GiB of VRAM capacity. In this case it’s because some GPUs have a 192 bit memory bus (it’s a half-way step between 128bit and 256bit) and use (usually) one memory chip for each 32bit slice. So you end up with 6*32bit memory chips. You can then pick e.g. 512MiB or 1GiB sizes for each chip, ending up at 3 or 6GiB respectively. GPUs in general have quite interesting interface widths: 64, 128, 192, 256, 320, 384 bit are all common. Combine this with the fact that most memory chips have a 32bit interface and you end up with total memory capacities like 12GiB (192bit/32bit\\*2GiB) or 10GiB (320bit/32bit\\*1GiB). Interface width is also the main reason why high end models usually have more VRAM and higher bandwidth. They just use more memory chips in parallel. But it is more expensive to do so.",
"It all comes down to bits, and simplicity. There's no reason an arbitrary amount of storage can't be used. You could arrange however many memory cells in whatever configuration you want for as much storage as you need. But how do you actually find what you're looking for? That process is called \"addressing\". Basically each bit that gets stored has its own address to tell the system where it lives. There's a lot of different ways to go about having an address and finding the exact place that memory lives, but since we're dealing with circuitry, it's very simple to deal with branches of 2. Imagine you're given a set of directions for a trip like this: \"left, right, left, left, right\". You just need to follow the road until you reach each fork, and take the path the directions say to take. The same thing happens for memory addressing -- each 1 or 0 in the address corresponds to a choice for which block to look at as you get closer and closer to the actual storage place. The first directions will usually refer to which chip group, then which chip within the group, then which bank within the chip, and so on... until the divisions get down to a small enough level to actually find the exact place where the bit is stored. (the memory/storage controller actually usually stops before this and works with a larger group of bits, but this is the general idea) For simplicity and efficiency, it's rare to have storage that doesn't have all of the routes populated along the way. That's why the storage capacity will be a power of 2, since adding more storage really is just a matter of doubling and doing the exact same thing, just with another layer."
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kycsn6
|
How can republicans be pro life while also being pro death penalty?
|
Other
|
explainlikeimfive
|
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"They don't even compartmentalize those two the same way. One is a bad person they have zero sympathy for and the other is the potential second Jesus. You'd be very hard pressed to find one of them who thinks criminals on death row need anything nearing compassion.",
"I’m not one of this belief system, but my parents are. Their argument is the innocence argument. A child is one of purity, and therefore has no reason to be killed. Someone who is receiving the death penalty is guilty to the most extreme extent, so they deserve to be killed. This is typically followed by “the murderer needs to be murdered so they don’t murder anyone”. Again, I don’t subscribe to this, but that’s the basis of it."
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kyd309
|
What's the difference between the real temperature and the "feels like" temperature?
|
Someone tell me if this is the wrong flair
|
Earth Science
|
explainlikeimfive
|
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"The feels like temperature takes into account humidity. On a hot dry day, it feels a lot cooler than on a hot humid day because sweat can evaporate a lot easier on a dry day, making you feel cooler.",
"The actual temperature is only part of the equation. Your body does not actually feel temperature. The body feels the transfer of heat. This is why metals feel colder than wood, when they both are the same temperature (assuming they are both below 37 or so degrees, if they are warmer than that, the metal would actually feel hotter). So the temperature feels lower when the heat is transferred away from your body faster. For example when it is windy, it feels colder. (Hence why we use fans, fans don't actually make the room colder, but they do help with transferring your own body heat away from you). When there is a high humidity it can feel either colder or warmer, depending on other factors. Water does transfer heat well, this is why it could feel a lot colder when there is a lot of moisture in the air in winter. But on the other hand, when it is hot outside, the moisture also prevents your sweat from being absorbed by the air, which means your primary means of cooling down no longer functions, which means it feels much hotter. So moisture, depending on context, can make it feel hotter or colder.",
"“Feels like” temperature is accounting for other forces that affect what the temperature feels like to us. It feels hotter when it’s humid because the sweat that we produce does not get evaporated like it’s supposed to when it’s hot and dry out. When it’s cold, but if feels colder, that’s because of wind chill (how hard the wind is blowing at you)."
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kydevq
|
why do we need toothpaste when brushing our teeth? Doesn’t the toothbrush do the work, especially if you have an ultrasonic toothbrush and fluoridated water?
|
Other
|
explainlikeimfive
|
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"The brush does a lot of work on its own. But the paste has super fine particles that get things the bristles cant. Most tooth paste also has ingredients for better tooth health.",
"Toothpaste has abrasives that helps to get the plaque off of your teeth. It also helps to prevent gum disease, tooth decay, and halitosis."
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7
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kydkxd
|
why does having a roof or even the bough of a tree over a car keep frost from forming on the windshield compared to a car without a roof or “covering” over it? It’s an open structure so it’s experiencing the same temperature and humidity, no?
|
Physics
|
explainlikeimfive
|
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"It's having something between the sky and your windshield, insulating it. The winter sky is very cold, and will radiatively transfer heat with whatever is below it (this is why cloudy mornings are much warmer in the winter than clear skied ones) Think of it like any heat that escapes your car going up flies all the way into space, while if there's a roof or tree or something a bunch of it bounces back down."
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kydray
|
Does hanging really kill by snapping the neck, not by stopping breathing?
|
Biology
|
explainlikeimfive
|
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"That's the intended outcome, yes. If the hangman screws up or wants them to go the slow way, it'll end in slow strangulation rather than a broken neck.",
"Actually it could have generally happened 2 ways. If the person was lucky, their neck would snap, and they would die quickly and painlessly. If they were unlucky, they’d be painfully strangled by their own weight until their death.",
"The depends on the type of hanging. The short drop hanging is when a person is standing on something like a chair or a box, and then drops a foot. This drop does not break the neck and kills by strangulation. In the standard or long drop, the condemned would fall several feet. If properly done, this would snap a person's neck.",
"It depends on how it's done. When hanging was used as a method of capital punishment and was performed by a professional executioner with the goal of humanely ending the person's life then things were setup to cause a neck break and quick passing. In cases where the hanging is not performed by someone who is knowledgeable of how to set things up to cause a broken neck then death is by asphyxiation."
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kydum2
|
How exactly does a “brain fart” occur?
|
So last night i had this said “brain fart” moment, i basically had a cup of hot chocolate in one hand and my phone on the other. While heading into my room i decided that i’d throw my phone on the bed, but for some reason i accidentally threw the cup of hot chocolate onto the bed making a huge mess. So how exactly does this happen? Does our brain just go dumb at simple tasks because it expects us to know what to do on our own? Appreciate responses that comes this way!
|
Biology
|
explainlikeimfive
|
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"I think one example that may have happened to many people is a situation like this: The person finishes eating yogurt, and goes to the kitchen to throw the plastic container on the thrash, and put the spoon on the sink to wash it later, but then, the person ends up (or almost) throwing the spoon away, and putting the plastic container on the sink. So, what is happening? The Brain has two types of memory for stuff we do, one of them is slower, but more careful, and the other is a quick, bot more prone to error. Think of the first time you learned some complex activity, like driving a car, playing a musical instrument, or some hard math concept. In the beginning you probably kept paying a lot of attention to what and how you were doing, and at some point it is a thing that you can do with little effort while paying attention to something else (just because you can, doesn't mean you should. Pay attention while you are driving, plz). Remember that I said that the first type is more prone to errors? It is an \"automatic\" thing that your mind does on the background, if something change, your brain may not pick that change, and do something wrong (e.g. If you drive everyday to work following the same path, and one day you are not driving to work, but the path is the same, until some point where it diverges. You forget about this detail and instead of turning left, you keep driving towards the path you go everyday). Well, that's basically what happened: Your brain decided that activity should go to \"autopilot\" mode, and maybe you are used to throw the cellphone on your bed with your dominant hand, but this time you were using the dominant hand to hold the cup, and you just realized the mistake after the damage was done.",
"They usually happen when you’re under stress, anxiety, or you’re sleep deprived. It can also happen when you’re just distracted and thinking of other things. It happens to me more often after a long day when my brain is overloaded."
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kyerne
|
How are the writings of dead languages deciphered?
|
Other
|
explainlikeimfive
|
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"Maybe without a reference you can't. Most languages have descendents so you could figure it out. But languages that have been completely lost need a reference to be translated. For instance [the Rosetta stone]( URL_0 ) had writings in hieroglyphs as well as Greek. Without that reference, ancient Egyptian language was completely lost."
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"https://blog.britishmuseum.org/everything-you-ever-wanted-to-know-about-the-rosetta-stone/"
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kyetu1
|
Why can't we recycle plastic in the same way we do for metal? Melt it and remold it?
|
Little edit: The question was regarding the mechanical/chimical aspect, not economical.
|
Technology
|
explainlikeimfive
|
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"Well, for one, polymers degrade when melted, so you can't just turn a PET water bottle into a new PET water bottle. It won't have the same properties anymore. You can use post-consumer recycled PET in something *else*, like a CPET microwave dinner tray, but even then you can't just use all of it, you can only use a small percentage of it. EDIT: That \"something else\" can, in fact, be a new bottle, but it will almost certainly be mixed with virgin material and won't be 100% recycled. For two, you can't mix types of plastics, which means that either consumers have to be exceptional at separating their types of plastic (by which I mean the cap *and* ring on your water bottle has to be separated since they're probably PP while the bottle itself is PET) or we have to have people sort through garbage bags full of recycling to separate it, which adds a hell of a lot to the cost. There's also the fact that most plastics have some additives in them, for one reason or another, and plastics with certain additives can't be mixed with others. For three, any contaminants (adhesives from stickers, residue from food or drink, etc) have to be washed off to the point where they're as close to completely gone as possible, which is basically impossible and also adds a ton of labor, again increasing the cost dramatically. (This is also true for paper/cardboard - STOP RECYCLING YOUR GREASY PIZZA BOXES, THEY CAN'T BE RECYCLED IF THERE'S FOOD OR GREASE STUCK TO THEM. *Edit: This may not be true, I'm not sure - my city explicitly says not to recycle pizza boxes with grease on them, but YMMV. Maybe someone with more experience in recycling, or paper/cardboard, can chime in on this one.*) For four, not all plastics are thermoplastics - thermosetting polymers cannot be melted down, they'll just burn up and release a ton of pollutants into the air. And obviously you can't mix thermoplastic polymers and thermosetting polymers. And for five, it's largely just not feasible to *use* post-consumer recycled plastics because it's 1) extremely expensive to buy and 2) can be extremely difficult to work into your existing process while maintaining quality and matching the needed performance without using so little that it's basically irrelevant. You're paying through the nose to use a tiny amount of the stuff you bought, just to be able to put a label on your product that says \"Contains post-consumer recycled material!\" Basically, plastic recycling - while it *is* done to some extent - is ***much*** more limited than the public has been led to believe, and in an amount of cases that would shock the average person, is outright impossible. I guarantee that 80-90% of the plastic items people put in their recycling bin actually end up in a landfill or incinerated because they can't actually be recycled for a myriad of reasons. Source: I work in QA at a plastics manufacturer. LAST EDIT: Okay, this comment alone now makes up more than 90% of my total karma and comments just keep rolling in, so I'm gonna go ahead and disable notifications. Sorry for not responding to all of you, there's just *too many!*",
"Not all plastic melts. “Thermoplastic” ones melt when heated, but “thermosetting” ones are made strong by complicated bonds that don’t break down with heat. They will catch fire first. This is a partial answer, naturally.",
"Plastic processing engineer here. Plastic parts can be ground and reused (regrind) but options for doing so are limited. Plastic has a heat history, the more you melt and reheat plastic, the more it degrades. As the plastic degrades you lose its physical properties. This means you have to use virgin material (no regrind) for many applications, such as automotove or medical parts. Regrind also can be more difficult to process, as it is more prone to part defects. Visible burns in the final product or brittleness would be a few examples. Regrind typically needs to be mixed with virgin material during processing to avoid these defects. The size of the regrind also matters. With virgin material the plastic comes in little plastic pellets, all the same size. When these are melted down they all melt at relatively the same time. With regrind you get bigger chunks and dust. The dust tends to burn while the bigger chunks may not melt evenly. There is equipment to remove dust and more evenly chop parts, but then there is now additional cost to reusing materials. Then you get into contamination issues. Typically when doing regrind you don't reuse consumer products, instead you are taking the scrap at the plant and regrinding it there. Even keeping it at the plant level, the chances for contamination is high. If a part is dropped on the floor and picks up dirt, now its in your regrind. There are many different types of plastic and each may require different processing temperatures. In many cases you cannot even mix different grades of the same material. I may have 5 different types of polypropylene at the plant. each with different fillers or additives that should not be mixed. This creates a logistical problem at the plant, because now you need 5 different grinders and 5 different storage containers for you materials. All it takes is one person putting the wrong part in the wrong bin or grinder and now you have a lot of scrap. Taking this a step further, this contamination could create machine damage in some cases. Incompatibile materials such as polycarbonate (melts at round 400F) and polypropylene (melts around 300F) mixed together could chew up your machines by running unmelted material through. Mixing materials such as PVC and Acetal can create explosive chemical reactions. Many common plastics are thermoplastics and can be remelted. There is another group of materials called thermoset. These materials undergo a chemical reaction to harden them. (example epoxy) These materials cannot be reverted back to their original form and recycled. TLDR: Some plastics can be reused, but process problems and costs make reusing plastics infeasible in many cases.",
"This is a great question and one that more people should be asking:) It start with the fact that not all plastics are the same, there’s all types that can’t be mixed together. So first off we need a better recycling system. For instance one where you would get money for the plastic waste you turn in. Like you get money for metals you recycle. Another thing is that with metals, because of the price difference it is neatly sorted. You’ll get a lot more money for copper then for mild steel for instance. Now to be able to do this we should get better at identifying plastics. You could start by learning how to identify the different types by looking at the recycling triangles! they should be on every plastic part you have and they can help you id the plastic. Now, you should also know that not all types of plastic are easily or even cleanly recyclable. But for the ones that are, yes we could melt them and remold them but, like you couldn’t melt copper and steel together, you cannot melt HDPE and PA together:) If you’re interested in all this be sure to check out Dave Hakkens and the project ‘precious plastic’! (HDPE is one of my favorites bc you can actually, safely, recycle that in your own oven:)",
"ELI5 for an actual 5 year old: Like metal, you can melt ice and freeze it in a different shape. Like plastic, you can't un-fry and re-fry an egg. It's also difficult to separate the quail egg from the Duck egg after stir-frying them together. This is not an exact comparison, but I guess it will do for a 5 year old. Plastic is really quite complex on a molecular level. Metals are simple.",
"Two large issues: * There is no such material as \"plastic\" - there are gazillion different types of plastic, just like how there are a lot of types of metal. So you have to work recycling out for every type individually. And not mix multiple types together. Just like with metals mixing random stuff together makes reusing it borderline impossible. * Plastics are FAR TOO CHEAP TO MAKE. They are made from ludicrusly cheap fossil fuel stuff. Due to this its simply not economical to recycle it - thats an unavoidable issue, even if you want to be enviromentally conscious with your company. As the company that uses non-recycled stuff can do its thing for cheaper, price better, and drive you into bankruptcy. & #x200B; Both issues can only (realistically) be solved by legistlation. & #x200B; On top of these, ther are technological hurdles. Stuff like plastics being made out of long chain like molecules, instead of \"just atoms thrown in randomly\". And with repeated reuse, molceular chains can break and thus shorten. Shorter molecular chain touches and connects to fewr other molecules, thus your material gets weaker. Ofc this issue can be circumvented by grading plastic - and designing the arts for appropriate strength. And when it becomes really useless you can still reprocess it chemically. Technological issues are - in some sense - easier to overcome than legistlative ones. As it can be done by a relatively small hard working group. With legistlative problems you have to fight against large mutlinatinals and various other interests groups pushing back with all their ~~bribing might~~ lobby power",
"I saw this video a while back [Limitations of plastic recycling]( URL_0 ) (I am changing the title because I think the original one was slightly misleading). The main idea is that plastic recycling is not a technological problem but an economic one. Either the technology to completely recycle plastic already exists, or if it does not, we can develop it. But, plastic recycling is not economically feasible. The world works such that if there is money to be made out of it, it will get done (even if it is selling children, or selling drugs, or selling drugs to children). But since there is no money to be made, we (as a country, or a specie) are not doing it.",
"One way to think of plastic is like a weave of long 'fibers' similar to a cloth, but much smaller. When it's originally made its quite strong because those fibers are so long and tangled together. Every time it gets recycled those fibers get pulled apart and many get broken into smaller and smaller pieces. Eventually those pieces of the original fibers are to small to weave together to hold a structure anymore and we don't have great methods for decomposing them back into the original components to make fresh new plastic 'fibers' or a eco-friendly by-product.",
"First, let's limit this to thermoplastics. That's a type of plastic that can be melted. HDPE, ABS, PLA, PET, nylon, polyester, polycarbonate, acrylic are some types you've probably heard of. A big part of the reason that metal is very forgiving when recycled is that the extremely high heat burns off contaminates, and most of what's left turns into slag that's easily skimmed off. It's also not a huge deal if a little bit of other metals/alloys are in the mix. Sure, that changes the alloy a little, but that's easily and quickly tested, and can be addressed. Metals can be recycled over and over, and aluminum is often described as being indefinitely 100% recyclable, and nearly 75% of all aluminum ever made is still in use in either its original or recycled form. Plastic is tough to recycle because a miniscule amount of contaminate, including the wrong type of plastic, can irreparably ruin the entire batch. It's also tough to sort plastic. Bigger rigid items are much easier because automated systems can identify, sort and clean them. Shreds and sheets of plastic are basically impossible unless it comes from a manufacturing facility that already presorts it. Yeah, they might be technically recyclable, but identifying, sorting and cleaning it from a mixed batch of recyclables is incredibly expensive. Like how do sort a \"polyester\" t-shirt? The fabric may be polyester, with cotton or nylon thread, a nylon tag, and possibly some screen printing or embroidery. Another problem is that the quality of plastic gets worse every time it's recycled, which limits its applications.",
"We can, but every time you do that, the quality of the plastic drops. For much of the plastic waste we would recycle, it is not even worth doing it once.",
"It's like reheating and reusing oatmeal, if it was colored green and cinimmon flavor before, you can't take that out. Not only will the texture not be quite the same as before from reheating, but you've got to find a product that it would blend well with (say apple spice flavor) If your bottle is green, you can't make a white bottle out of it, and it wont be the same as the fresh plastic anyway",
"Here's a real attempt at an ELI5 answer. The \"simple\" answer is \"chemistry\". When you melt some things, like water, by applying heat, they just become different versions of the same thing. In fact, for those substances, we tend to purify them with heat. Different things melt at different temperatures, so if we heat substances to very specific temperatures we can separate the stuff we want from the stuff we don't. For example, gold melts at a different temperature than the rocks it's usually found in, so when we throw giant batches of rock into a furnace we get pure gold with still-solid \"slag\" on top that's easy to separate. This only tends to be true with very simple chemical compounds. Since gold is an element, it's as simple as a compound can get. Given any kind of material, we can create a process that will extract gold from it if any gold exists using our knowledge of chemistry. Or, think about paper. If all you did was write on it with normal ink, we can shred it, throw it in water, bleach it, and produce new paper based off those clean wood fibers. The bleach destroys the chemicals that make the ink visible, then the remnants evaporate. However, if instead the paper was used as the wrapper for a greasy cheeseburger, we have to add a step to our recycling machine to deal with the fat related to the food it soaked up. Fat doesn't evaporate, so we have to work harder to remove it, hard enough that it's easier and more efficient to plant new trees so many recycling plants won't deal with paper that has food residue on it. However, plastics are extremely complicated chemicals. To be stable, they require very specific ratios of materials to be brought to very specific temperatures. Too hot or too cold, and they don't make plastics, or they don't make the kind of plastic we were trying to make. That makes recycling plastics very difficult. Some plastics, when melted, cannot reform into the same kind of plastic they were before melting. In theory we could force this to happen, but it involves adding so much heat and so many new materials that it is more wasteful than just letting the plastic go to a landfill. Imagine if you have a $5 bill, but to make another one you have to spend $20 of materials. That's not going to make money. However, it's usually true that we can take a \"complex\" plastic and recycle it as a \"simpler\" plastic without spending as much energy or material as it takes to make the \"simple\" plastic from scratch. So some of these plastics can be recycled, but they don't end up being recycled to the same kind of plastic as they started. This is overall the conflict with recycling: some forms of material recycling cost us more energy and pollution than just manufacturing a new copy of the old thing. If our goal is to reduce pollution, we have to be pragmatic and admit that we just can't recycle some things in a way that helps the planet. However, this leads to other tradeoffs. For example, a milkshake that costs $2 in a styrofoam cup that is impossible to recycle might cost $6 if offered in a completely reclaimable glass container. A lot of people argue it'd be a shame if we lost money like that and found out the only benefit is a cleaner planet.",
"In Sweden we recycle 84.1% of all PET bottles. You get between 1-4 kr per bottle (0,1-0.4 US dollar) when you recycle them. There is sometimes a holder for cans and bottles at the side of trash cans so it’s easier for homeless people to collect them. Win win!",
"Metals are elements: Iron (Fe), aluminum (Al), gold (Au). If you melt them you still get iron, alumium, gold, silver or whatever. Plastic instead is a compound of long chains of the elements hydrogen and carbon. By melting they'll break apart and you'll get something completely different.",
"We recycle food package plastics here in Finland, started a year or two ago. We got a separate color bin for them. Gotta wash and dry them first and check if they have \"PVC\" or \"03/3\" markings on them, and if not, they are good for the plastic bin. But that's the extent of my knowledge. Many do it, once you get used to it, it's no bother. We already had separate bins for paper, cardboard, bio, metal, glass, etc, so it's just one more thing. :)",
"It’s a chemical reaction. It’s like why toast can’t become bread again (this is eli5 answer)",
"I'm a geologist and one of the places I commonly have to work is recycling facilities. All of the recycling that is put in the bins every week goes to a crusher is dumped in the bed of a semi and hauled to a landfill. Honestly, it's fairly disappointing because they're typically making a much bigger mess at the facility pretending to recycle than actually just throwing it in the dump, but whatever makes folks feel good about it I guess...",
"so y’all haven’t heard of the precious plastic project? URL_0 We can recycle plastics on a small business scale. Granted it’s not industrial, but it’s pretty amazing how many products you CAN make with used plastic. Precious plastic is an initiative started by engineer Dave Haakens in the mid 2000’s. Since it started, it has grown to show individuals how to do plastic recycling on their own. It has all you need to start your plastic recycling business: -blueprints and tutorials on how to build shredders, injectors, ovens and molds to repurpose various grades of plastic. - educational materials on how to safely work with thermoplastics -tutorials on how to start your own small business (storefront to finance) -designs for products (ranging from artsy looking bowls to straight up construction beams that can be used to build playgrounds etc.) -message board and community to outsource trouble shooting and start partnerships. Though it’s not exactly 1:1 recycling that people envision, precious plastic is pretty incredible and shows that we can recycle plastics if we get creative.",
"Nevermind the bs.. there is no money in it, so people can't get rich. Metals are worth money, plastic is not.",
"Plastic is an umbrella term for two different families. Thermoset plastics form and cannot be reformed (they burn and become completely unusable) Thermoplastics can be melted and reused.",
"When I was a kid plastic was rare. We returned glass bottles or reused things. How about we go back to that? Get rid of as much consumer plastic as possible.",
"If more people used Polycopralactone it would be awesome. It becomes like clay in hot water. But kind of expensive right now. Greatest craft plastic ever. Seems to be non toxic too. Though I am no expert on plastic toxicity.",
"Simply just because it’s not profitable This video explains the how and why. Also plastic recycling is a ploy used by the plastic manufacturers to help use feel good while using plastic URL_0 (How China broke the world’s plastic recycling industry)",
"Tangential question: Why ban plastic shopping bags? Like, we use those shopping bags as our trash bags, which is what I assume everyone does. If we didn't have those shopping bags, we'd have to go out and *buy* trash bags anyway, and those are usually thicker plastic than shopping bags.",
"Broadly speaking there's two types of plastics. Thermoplastics and thermosets. Thermoplastics actually can be melted down and reshaped and recycled. However, thermosets are significantly better in just about every way. They're stronger, more heat resistant, experience less fatigue from stresses, etc. They're just the better material to make things with. And they're cheaper. But they can't be recycled.",
"Robots love sorting recycled materials. Working with three companies to increase picking efficiency above the 80ish % . I was told this week that HDPE, think milk jugs, is fetching more money than aluminum...even in these times of low oil prices. As a consumer, dont give up on recycling. There are A LOT of very takented people working to solve this issue.",
"Metal is a vague term. There are many kinds of metal and you wouldnt want to throw them all together and melt them. Different metals would also melt at different temps. The same goes for plastic. There are many kinds of plastic and you wouldnt want to throw them all together. Plastic is an organic polymer and not all of it will melt, some will just burn, just like you cant melt meat.",
"Depending on the plastic, we can just melt it and reuse it. Some plastics are basically too sensitive to heat and break down while melting. The result is a useless sludgy mess of a substance that can't efficiently be reused. On the other hand, there are plenty of plastics that melt down and reshape very well, the plastic used in milk jugs, for example. Many items are made with this plastic, but in general, cheap un-reusable plastics are used because they're cheaper to produce. An example of this un-reusable plastic would be the plastic used in a bag of chips (crisps, for you UK folks).",
"There's lots of good answers, but I'll put this in too. I work in a plastics manufacturing plant; we make plastic bags from mixes of low density polyethylene and high density polyethylene specifically. We *want* to use as much recycled plastic as possible, as this allows us to re-use our own scrap/waste. But in practice, as per u/ErikPanic 's excellent post, plastic degrades when melted. We're basically limited to ~5-10% by weight of recycled plastic, and this is remember *exactly the same material, before printing*. Once the plastic is printed, it's basically unusable to us for recycling because the ink acts as a (very inconsistent and low quality) dye. So, assume we've just got a tiny amount of simple black print, a bit of text, on clear plastic bags. Now if ground up and reused, that clear plastic is now smokey black plastic - but worse, because the plastic is degraded, and the impurities (ink) degrade it even further. So in practice, just how much you actually can recycle plastic is (as others have said) very, very limited.",
"Plastic is a broad term for a lot of different materials. They have in common to be chains, but some are more knotted then others, if they are too knotted you can not disassemble them with heating, much like you can not loosen knots by just pulling on the ends. This type of Plastic is called Duroplasts, the only way too reuse it is to shred it into pieces and use the pieces for a different purpose, for example in roadbuilding. Others, called Thermoplasts, can be disassemble with heat, because they are not as interwoven. But each time you heat it you also cut some of the chains. And with shorter chains it loose its functionality. And you can't reuse it if its a mixture of different Thermoplast, or if it is too dirty. Metal is more like Water, you can freeze it and melt it as often as you wish, because you are not destroying anything in this process. An other example would be: Plastic is like Fabric, if you dislike your Dress you can cut and make something smaller, but you cannot make the same Dress with it after you cut it. Metal is like Lego, you can build and disassemble it as often as you wish"
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[
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[
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kyf05g
|
Why is it that everything in Australia is the most poisonous/venomous? Snakes/spiders/plants?
|
Other places have plenty of poisonous shit, but the most worst of every category are all in Australia? What is it about Aus that causes that?
|
Biology
|
explainlikeimfive
|
{
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"Australia doesn’t actually have that many poisonous/venomous (poisonous actually isn’t the right term hear, a snake that bites you and injects you with something isn’t poisonous, it’s venomous, while something that you eat and then kills you is poisonous, basically venom bites you, you bite poison.) l animals in it. Just for brevity purposes I’m gonna just keep saying poisonous in the rest of this post, but I mean poisonous/venomous. Brazil and Mexico both have more poisonous species than Australia does. Really, all tropical areas have on average more of some form of poisonous animal, the most common being spiders or snakes/reptiles. The theory behind this is that since the tropics have more energy on average (more sunlight, which makes more plants, which makes more animals that eat plants) it is easier to sustain a high energy activity like making your own poison, compared to more northern/souther climates. Really, Australia just gets a lot of media/meme attention, particularly cuz it has the platypus, the only poisonous/venomous mammal, but in total numbers it really isn’t that crazy.",
"It doesn’t. The media just likes to amplify anything venemous or poisonous in Australia. But we’re a developed, stable country so lots of people from other developed countries visit here and haven’t had much experience watching out for things like spiders/snakes so they think it’s a huge deal. South America and Southern Africa have more dangerous animals but often people are worrying more about the humans as that’s what the media tells them to watch out for. I lived in Mexico and had people say Australia sounds ‘so scary because of all the dangerous animals’ and I’d be like ‘you are driven to school in an armoured van and have 24/7 security but you think Australia is scary??’. Anyway, point is that humans are far scarier than animals. Animals are, for the most part, predictable."
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kyf8qp
|
How does the cellphone knows its on the horizontal or vertical position? How exactly those sensors work?
|
This is quite a puzzle for me because I don't think its something mechanical because cellphones are slim and compact you can't fit something mechanical in there, and if its a software I don't understand how can a program sense something physical ?
|
Technology
|
explainlikeimfive
|
{
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"It is something mechanical; it's just very, very small. First of all, in order to understand how it works, you have to know about two things: First is that gravity is, from a physics standpoint, indistinguishable from acceleration. This means that, even at rest, the cell phone can detect the acceleration due to gravity and know which way is down. So your accelerometer and orientation sensor are really the same sensor. The second is that there exist substances which are *piezoelectric* (most are crystals or ceramics). This means that they have a different electrical charge depending on how much mechanical force they're being subject to. Put simply, the more you squeeze them, the larger the electrical signal is. Now, inside your cell phone is tiny mass at the end of a tiny fixed beam. (I'm going to stop saying tiny now; it's all tiny). Also attached to that mass are beams which have piezoelectric sensors in them. As the mass is moved by changes in acceleration, the force on each of the sensors varies. If you're moving the phone upward, the down sensor has more force on it; if you're moving it to the left, the right sensor has more force on it, and so on. By measuring the changes in electrical charge of those piezoelectric sensors and combining them (so if it sees the down sensor and the right sensor with higher signals, it knows it's moving up and to the left), the phone knows which way the phone is oriented and moving and can report that to the operating system."
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kyfvfd
|
Why is Trigonometry used in so many applications that have nothing to do with triangles?
|
Mathematics
|
explainlikeimfive
|
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"While the origin of the word relates to angles and measures of a triangle, it is probably more useful to think of a triangle as the simplest polygon and that an \"extreme\" form of regular polygons, ie with the \"most\" sides, is the circle. In that sense, the subject develops naturally to the study of circles and of particular importance in the real world, circular motion. With the further development in mathematics, it has been shown that any closed shape can be inscribed as a series of circular motions of circles of various shapes (although the number of circles might be very large to the extent of requiring an infinity of circles). The other property of circular motion is that it is periodic (ie it eventually repeats). This is very useful for the analysis of periodic motion - the simplest being what many people think of as \"waves\". Waves appear to be a very fundamental property of the universe (light waves, sound waves, radio waves etc etc) So the mathematics of trigonometry lead to circles and circular motion and then to waves and periodic motion in general. It becomes foundational to nearly all physics and engineering.",
"Everything, and I mean everything, can be broken down into triangles, yes, even circles. If you know your way around a triangle you can calculate anything.",
"I am a mathematician. Triangles are used to calculate forces acting on objects at angles. In the simplest case, suppose you have an object sitting on an incline and want to calculate the rate of acceleration that it slides down the incline. Normal gravitational acceleration is 9.8m/s^2 however, the incline changes that. This is where the trig comes in, to account for the angle that the object is sliding down.",
"The first lie they teach you about trigonometry is that it comes from triangles. Trigonometry comes from properties of circles and the triangle stuff is just one useful application (if it came from triangles, then expressions like sin(190°) or cos(5pi/4) would not make any sense, since triangles can't have angles that big). Circles in turn provide a very nice example of periodic motion: Going around a circle one and a half times puts me in the same place as going around it halfway, or two hundred sixty nine and a half times. If we for example want to understand something periodic but more complicated, then you can break it down as a sum of a bunch of sin and cos functions which is easier to analyse than a very complex expression."
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kyg0uy
|
How is England a country, but the UK is also a country?
|
Other
|
explainlikeimfive
|
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"England, Scotland, Wales and Nireland are all countries, but they are not sovereign states. Only the UK is a sovereign state with the power that grants. The distinction between the constituent countries is solely for internal governance. England for example has no international relations, neither does scotland, only the UK is a recognised political entity on the world stage. For all intents and purposes, England, Scotland, N Ireland and Wales do not exist outside of the UK, because no country can deal with any of those 4 independently. And as to your example, no. An Englishman has no social status as ‘English’, he only has British citizenship. As does a Scotsman, as much as the Scottish may dislike it. Edit: This is ELI5, please stop flaming me because i left out a technicality that you personally care about. These are the broad strokes.",
"\"Country\" doesn't mean what you think it means here. The UK is a sovereign state, in the same way that the USA is a sovereign state, or Canada is a sovereign state. England is a country within a sovereign state; Ohio is a state within a sovereign state; Ontario is a province within a sovereign state. In this instance, country = state = province (generally speaking). England, Ohio, and Ontario are not sovereign states themselves - they're **governed by** a sovereign state. Basically, different words are being used in different regions that mean largely the same thing. The USA just decided to call its subdivisions \"states,\" even though the term \"state\" generally refers to a **sovereign** state. (The USA is not the only sovereign state to do this, but it does lead to some degree of confusion in instances like this.)",
"I don't have much to offer, but CGP Grey does a really good video quickly covering all that information: URL_0",
"And what's great britain then? And what the hell is the commonwealth? Most importantly, where's King's landing?",
"As an Englishman, I can tell it's a bit of a mess - governed pretty much entirely our historical and traditional hatred of each other - but the same hatred you might have for a sibling, we can call the Welsh names - but so help us if anyone else gives them the side eye. Best explanation I've seen is in this video by the incredibly eloquent CP Grey, but I'm not sure if I'm allowed to link to it here. England, Wales, Scotland and Northern Ireland are the big players, and are to most of us what we consider \"the UK\", if you live in the border towns (say Bristol) it is entirely possible to live and work in separate countries - but a house would never be in two countries simultaneously. The borders between the countries are more like the borders between states in the US and less like the Mexican border. There are some toll bridges and roads between countries - but you're paying to use the road, and not to get checked to enter the country. As far as government goes, England has the main body of government - what you see on TV (maybe) with Boris Johnson and the MPs in the Houses of Parliament - but the other countries have what is called \"devolved Parliaments\", where they have certain powers over what happens inside their own countries (for Scotland they have the first Minister Nicola Sturgeon, who seems to have gained a decent amount of acclaim, especially compared to Mark Drakeford of Wales, Northern Ireland doesn't even seem to have a head of their assembly). Then you have the Commonwealth - a political alignment of over 50 countries, most (if not all) used to be part of the British Empire from the old days when we would sail around the world sticking our flag into wherever we landed - but at some point the British Empire used to include Australia, India, the initial 13 American colonies, a good chunk of Africa - all ruled under a single monarch. Tldr - it's a cluster fuck, multiple countries, single ruler with some devolved powers for the individual countries - much like how states have local powers. Hope that helps.",
"So many years ago before we invented America, and owned most of France, When the country would be ruled by the monarch (King or Queen) We either through war or marriage took over these countries and in the case of Wales - principality. So the monarch became \"owner\" of Scotland Ireland and Wales. However, to give them a sense of self they remained mildly independent - they show loyalty to the Monarch. So the tribal chiefs of each country (or Principality) would supply troops or taxes to the crown. These chiefs may have been given large areas of these countries as gifts for loyalty in Battle or in the royal court. But they were still a different country. We could have done the same with France but wrong side of the channel and too many other countries interested like Italy. So you end up with 3 countries, and a principality, under the control of the monarch. As we developed Government and politicians, what may apply to England wouldnt necessarily apply to Scotland due to things like ancient land rights etc so each country and Wales (a principality) would have slight variations in law. Ireland was given partial independence which is why you have Ireland and the occupied area called Northern Ireland. Each have a separate parliament and some areas of power are devolved. In Scotland this is quite extensive now, in Wales they can put welsh language signs up next the the proper English ones. When it comes to sport, we have separate teams to represent each country (and principality) because they have separate leagues for sport, mainly because if most of the welsh teams were in the English league they would be filling up all the lower leagues. There are some ridiculous anomaly's, 2 welsh clubs Cardiff and Swansea are in the English football league and although not very good, they come under the jurisdiction of the Welsh Football association (FA) so the Welsh FA often over turn red cards (if a player gets sent off in a football match they get a red card and can be banned for 1 or 2 games), even when its completely outrageous but to be fair they need all the help they can get. The welsh and Scottish are extremely ungrateful for everything the English have done for them and especially on the sports field always play up the huge rivalry. As the English always end up winning in the long run the English dont really care and allow them the odd win here and there to make the games more interesting. If scotland win a football match they go on about it for years, forgetting the last 20 fixtures have been won by England. The Irish have wrongly been occupied for many years and have a true gripe with the English, but thats a wholly different complicated discussion. Basically the English are in charge and like a parent with a young child let them choose what they are going to eat to give them a sense of independence. To this mix you could add the great nation of Cornwall, probably the best county in England and should be a separate and independent Country. Its probably the only Celtic County in the Country, related more to the Celts of Brittany, Basque and Ireland then the Saxon invaders. Would also say, the Scots are probably the bravest and best fighters - i would rather have a company of Scots fighting next to me then any one else if i was in that situation and i have never met a Welshman i didn't like. I'm also Irish/British dual nationality and a European. Finally England is turning into a bit of a shit hole politically its become a corrupt and useless country, Boris is like Trump lite, but without the charm of Trump. Anyone not offended?"
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|
kyg5yk
|
- Why is Venus' atmospheric pressure so dense?
|
I understand why it's so hot, but I can't wrap my head around its atmospheric density. 90x the pressure on earth. it's roughly the same size, and in the same general neighborhood. what causes the crushing pressure?
|
Physics
|
explainlikeimfive
|
{
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"The higher pressure is due to the atmosphere and what it's made of. Earth's atmosphere is mainly oxygen and nitrogen both have a certain weight due to earth's gravity. Venus gravity is lower than earth's. 8,87m/s vs 9,81m/s. But Venus' atmosphere is 96% carbondioxide. This is much heavier than 21% oxygen and 79% nitrogen. Thus the pressure is higher. If we keep pumping carbondioxide into the atmosphere we are basically Terra forming, turning earth into Venus. But this would take millions of years but it possible."
],
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|
[
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[
"url"
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kygjc1
|
why do we act like dummies around crushes
|
I'm pretty sure everyone has had this experience. Why is it so common to suddenly not have the ability to show your best self when around someone we are attracted to in those early crushy days? What's actually happening? Any social scientists have a decent explanation? Do animals do this? I want to know more!
|
Biology
|
explainlikeimfive
|
{
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"Believe it or not, just seeing someone you're attracted to has major effects on the brain. There is some evidence that it immediately deactivates the parts of your brain dedicated to 1) decision-making and reasoning, and 2) processing negative emotions. This might explain why you get giddy and excited and stupid whenever this person gets close to you. Not just that, but it also seems to affect which neurotransmitters, or chemical messenger molecules, are sent back and forth and being used to communicate within your brain. You'll get hit by a surge of dopamine, which is sometimes called the \"feel-good\" hormone. Other ways of triggering dopamine release in your brain include by eating and/or drug use. You'll also get a blast of adrenaline, which is the fight-or-flight hormone that makes your heart rate go up. I'm sure a scientist or clinician can expand on this but it is truly remarkable what happens in the split second that you see someone you like!",
"I believe that all them hormones quite literally affect the way your brain works, inhibiting part of your rational thinking abilities.",
"Physiological effects wrote in this thread are great answers but there's a complementary very simple psychological explanation : You start watching your every move to avoid looking bad which makes you act very unnatural. You also try your hardest to be at your highest but this ends up being your weirdest because you're not used to it and people at their best don't force it."
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[
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[
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kyglp4
|
Why do gas burners go from off to high to low? Wouldn't it make more sense to go from off to low to high?
|
Technology
|
explainlikeimfive
|
{
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"text": [
"It's so that you can minimise the flame on the burner without risking having the whole thing turn off. If it was the other way around you would often try to set the gas even lower to the point that it could easily blow out. But you don't try to adjust a high flame down towards the off position, so it's more reliable (and safer).",
"They need to put out a high volume of gas in order to ignite, then the user can adjust it down to the desired output.",
"Because it needs that higher gas flow to turn on safely so that all the gas burns and doesnt build up, so when you start it, it starts on high gas flow, then you can safely turn the flame down, while still burning all the gas because it already has a flame.",
"Depends on the burner setup. My stove you have to go all the way up to ignite, then it is Light- > High- > Med- > Low- > off. I've also had stoves that go the way you've indicated. So it's a manufacturer discretion thing"
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[
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[
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|
kygmex
|
How do male seahorses give birth? Surely if they have the means of reproduction, that makes them female? What do female seahorses do in this arrangement?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
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],
"text": [
"We commonly say they give birth but that isn't quite right. Like other fish, they don't give birth. They lay eggs. Specifically the females lay eggs, but they lay them in a pouch on the male. While in the pouch, the eggs are fertilized and eventually hatch. When the little fish fry eventually come out of the pouch, it *looks* like a birth"
],
"score": [
21
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kygrxw
|
is water from the dehumidifier and tumble dryer collection tank safe to drink?
|
Chemistry
|
explainlikeimfive
|
{
"a_id": [
"gjfxytt",
"gjg1pxi"
],
"text": [
"I wouldn’t drink it. Technically, condensed water is usually fairly pure, but these machines are not designed for this. How clean are the water tubes? How clean are the condensation coils? It’s like licking the condensation or frost off the inside of a window.",
"Only if you filter it. Dehumidifers are constantly cycling air through them as they run. While condensed water itself isn't unsafe to drink, particles of dust and other contaminants in the air inevitably come into contact with the condensing surface and will contaminate the water. Also, because the water is sitting in a still container, it becomes a breeding ground for bacteria. If you absolutely must use it, I recommend running it through a good water filter and then bringing it to a boil, just to be safe. Same goes for the tumble dryer. That water may be condensate, but it's inevitably going to be contaminated with other compounds."
],
"score": [
13,
6
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kyh8ec
|
Why is it that many of our memories can only be accessed in our brains after we are reminded of them?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gjg1vnd"
],
"text": [
"The memory you are talking about is associative, meaning things and events are linked together so when you are reminded of something it activates all the things associated to that memory giving you more detail about the memory itself. & #x200B; Edit: maybe you're wondering why we can't just access our memories at will? Well it's because those memories might only be weakly associated to things in your day to day, you don't want to remember everything all the time, so it requires a certain activation of pathways to trigger that memory. This is why sometimes retracing your steps, either physically or mentally, helps if you have misplaced something."
],
"score": [
21
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kyhajr
|
why is it so much more difficult to wash oil off plastic containers than glass or metal ones
|
Chemistry
|
explainlikeimfive
|
{
"a_id": [
"gjg7kjr"
],
"text": [
"Plastic is porous in a way that oils like to slip in to it. Which is why greasy and oily foods can colour the container, especially when the surface is worn and scratched. Meanwhile metal* and glass isn't. (Steel and aluminium are, but not so much that oil or greasy can soak in to the structure in a practical sense, but give it a long time and you'll never get that smell out of it)."
],
"score": [
5
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kyhkto
|
How do we find out whether two people look at a color in the same way?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gjg4ma6",
"gjg4x8h",
"gjg6iex"
],
"text": [
"Well, we can't. There is no guarantee that what you call blue is the same in someone else's brain. What's even more complicated is that colours are constructed by your brain and not necessarily faithful to the stimulation from light on your eyes, making matters even more complicated.",
"The short answer is that because they both look at the colour and say \"that's red\" or \"that's mauve\". Do they really see the same thing though? If you could somehow put yourself in someone else's brain would you discover that how they see red is actually how you see blue? Putting the question like that shows how hard it is to answer this question, and perhaps how it's kind of meaningless. What does it mean to say 'put yourself in someone else's brain?' However we can say that people experience colours in both similar and different ways. For example red is a warning colour in nature - but also a colour of excitement - so as a species we're evolved to respond to it. On the other hand, if you say you love the colour red and I say I hate it, then clearly we're having different experiences when we see the same colour.",
"There’s a sort of philosophical angle to this as well, if you want to get into the “theory of knowledge” (or epistemology I think is the term). Basically everything we “know” can be reduced down to assumptions that we make that are “safe” assumptions because there’s a lot of other evidence that supports, confirms, “jives” with those assumptions, and it all helps the world make sense. Even before studying the physics of eyeballs we have enough anecdotal information to see that humans generally respond in the same ways to the same colours (can say that a colour is a light or dark shade of blue and be consistent with how others perceive it). This is how we also discovered colour blindness, was in that certain people had a consistently different set of responses to reds and greens. Putting it all together, you can “safely assume” most humans see colours the same, except for the ones that category that don’t because they have colour blindness. Then you can add a scientific layer with a bunch of further “safe assumptions” about science and how we’ve studied eyeballs, rods and cones, and how they interact with light and so on... I “know” humans can’t fly, but this is really just a very safe assumption I make based on the fact that I’ve never ever seen a human fly, and I know that I can’t."
],
"score": [
7,
4,
3
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kyhyu5
|
Why can't we burn plastic and use it as fuel since it's flamable?
|
Chemistry
|
explainlikeimfive
|
{
"a_id": [
"gjg9rxk",
"gjg7p93",
"gjgdn5u"
],
"text": [
"Well, we *can*. Some places *do*. It's just a very difficult process. Not super efficient and very unclean. Some plastics lens themselves to it better than others, but in general you need to have a really good way of filtering your exhaust. While this *is* an option for disposal of plastic, it is not super economical in most places when you can just throw the stuff out.",
"compared to regular gas or coal, it doesn’t output as much energy. approximately it creates 25% of the heat that coal would. burning plastic is also very toxic, so it would be better idea to just recycle it instead of burning it as an efficient fuel source.",
"\\- Creates toxic fumes \\- Not very energy efficient \\- The ashes are difficult to recycle"
],
"score": [
7,
5,
3
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kyi27f
|
Who would be the indigenous peoples of Europe?
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gjgdcic",
"gjg8gvv"
],
"text": [
"This is not an objective question considering there is no cut and clear definition of indigenous people of Europe. If you mean who were there before the Indo-European language speakers, then the answer would be '[Western European Hunter Gatherers]( URL_0 )' and '[Eastern European Hunter Gatherers]( URL_1 )'. The contemporary nations that you can trace back to have been the oldest peoples to survive the Indo-European migrations would be the Basque people and The Finno-Ugric people. & #x200B; TLDR: **Basque people** (Minority in France and Spain) **Finnish people** (Finland) **Sami people** (Sweden/Norway/Finland) **Estonian people** (Estonia)",
"Europeans are the indigenous people of Europe. 'Indingenous' does not imply that they can't be the dominant cultural group. But there is no clear boundary between indiginous groups. The UK has been invaded or inhabited by many foreign groups over the centuries, and so it doesn't really make sense to claim any demarcation between indigenous British and non-indigenous British. Talking about Indigineous groups really only makes sense when there's a clear separation between one group and another, as there is for the indigenous people of Australia or North America, among others. In Europe, these groups largely do not exist, because everyone has been intermingling with everyone else for centuries."
],
"score": [
6,
6
],
"text_urls": [
[
"https://en.wikipedia.org/wiki/Western_Hunter-Gatherer",
"https://en.wikipedia.org/wiki/Eastern_Hunter-Gatherer"
],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kyj68j
|
Why does listening to some music give us more satisfaction than other music?
|
I heard that music gives you satisfaction because your brain creates a feedback loop of predicting what music will come in a second, and then rewarding itself if it was right. But in that case, why does some music give us more satisfaction than other music?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gjh34w3",
"gjgrtvx"
],
"text": [
"Part of it has to do with tension and release in music. Similar to reading a story, if you were listening to a song and it never really “went” anywhere, you would get bored pretty fast. Satisfying music introduces you to something that feels like the “home” of the song, before taking you somewhere else. Tension builds when you are taken away from that home, which makes it much more satisfying to come back, rather than having stayed there the entire time. This time “home” might be the chorus, having some similar attributes to the introduction of the song, but also surprising you by adding or taking away certain elements. This is another huge contributing factor; playing with expectations. While it might be true that your brain rewards itself when it’s correct about guessing what comes next (not sure how true that is but rollin with it), it’s much more rewarding when something doesn’t exactly meet your expectations. Again, compared to story telling, if you knew exactly what was going to happen, it wouldn’t be as satisfying as a new adventure. It might feel more like recalling a memory. Satisfying music conditions you to predict how the song is going to go, then does something different that isn’t as obvious but still fits with the song. These are just two examples that stick out to me as highly contributing factors. I’d love to hear the others that people come up with.",
"I can't explain it, but I am a sucker for a hook. So several years ago I learned about Pachelbel's progression. The specific combination of the chords is so pleasing to us humans. Many songwriters use it, Blue's Traveler most cleverly in \"The Hook\""
],
"score": [
5,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
kyk692
|
What defines a new species?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gjgpgxn",
"gjgr76i",
"gjgsmyq"
],
"text": [
"The basic definition of a species is a group that will mate and produce fertile offspring. So as long as people from all parts of the world can bang and have babies who can bang and have more babies (after they grow up - ew) then we're still one species. In contrast, horses and donkeys have split, and are considered different species, because they can mate and produce offspring (mules), but mules are sterile. If Irish people suddenly started having sterile babies whenever they married non-Irish people, then the Irish would officially be a new species.",
"The reason you notice so much difference in different human races is because you are used to noticing these differences. Other species have just as much disparity in how they look but since you are not used to looking at them it is hard for you to notice it. But if you spend time around the animals you may notice some of their differences. You may for example be able to tell the different races of dogs, cats, cattle, horses, sheep, etc. from each other just like you can tell different human races from each other. We used to define a species as a population that could create non-sterile offspring with each other. This definition was widely in use for a long time and is still used a bit in non-scientific communities. However there are some serious issues with it when you start looking at some of its edge cases.",
"This is a very complex question. In its simple form, a species is a group of related individuals known to reproduce naturally in the wild. However, this is complicated by the idea you may have two populations of the same species that are separated by some boundary. They don’t reproduce in the wild, but could if they were in proximity. So we move on to genetic definitions. The genetic definition of species is even more wishy washy. When you map the genomes of different members of a genus, and find that several populations are much more closely related to each other than they are to the rest, you might suggest they are of a species separate from the others. At the end of the day, species is a human term used to impose categories on nature when there really aren’t discrete differences. We all evolved from the same organisms, so declaring that some are or are not the same species is somewhat arbitrary."
],
"score": [
9,
3,
3
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kykfw7
|
Why can't we recycle styrofoam? Seems like it's just a bunch of tiny balls molded together that could easily be reshaped over and over.
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gjgumj1",
"gjgvexu",
"gjidkl1"
],
"text": [
"We can recycle styrofoam. There are many producers of styrofoam and other polystyrene products that do accept recycled styrofoam. But there are issues both of transportation and sorting. Firstly sorting different plastics from each other is a very difficult job. Most consumers will just mix different plastics together and even producers will use different plastics in their product making it impossible for consumers to sort on their own. And because different plastics can look so similar it is not something that humans can be able to sort either. This requires dedicated robotic sorting machines that can use various different sensors to differentiate between different plastics and sort it. And although they are coming onto the market now they are very expensive. You might imagine that styrofoam is an exception but there are various different plastics that can be expanded into foam to make something similar to styrofoam but which is made of different plastics then polystyrene. As a twist of fate the recycling efforts of styrofoam have a lot of issues with companies using starch based foams in their packing and promoting it as biodegradable as this will mess up styrofoam recycling when these two very different products gets mixed up. The other problem is that styrofoam have very low density. So in order to transport it from the sorting plants to the factories that use them you need to use a lot of big trucks which would end up carrying almost no weight. This in itself costs more money then making polystyrene from scratch and releases more green house gasses as well. So by recycling styrofoam you might end up increasing your carbon footprint compared to just burning it for energy. There are some cases where big compacting machines can get the density high enough that transporting it to the factories does make sense but that too is very situational and depends on the distance and the cost of transporting the materials for new polystyrene.",
"Chemicals are mixed together to make the foam and those chemicals cant be un-mixed. Once the foam takes shape it can be further shaped by reduction but not addition without the use of adhesive. The foam can be melted down with acetone and reformed like dough that will dry into a harder denser plastic, but I dont know how economical that is. It is usually only for DIY purposes. Mycelium (the part of mushrooms that grow underground) can be grown in molds and used in place of foam is a much more eco friendly and cost effective solution than finding a way to reuse foam would be.",
"Polystyrene foam can be recycled but as with all plastics it cheaper to use virgin stock due to cheaper oil. The market just isn’t buying it."
],
"score": [
33,
5,
3
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kykkp2
|
Why are most songs about 3:30mins long and not longer or shorter? Why is the standard length varying between genres (and during the time)?
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gjgy5ji",
"gjgszib"
],
"text": [
"During the days when vinyl records were the way everyone stored and recorded music, there were standard 10 inch \"single\" records that held about 3 minutes worth of music. Depending on the quality of the sound you wanted, it could store up to 5 minutes. As radio blossomed in popularity, they needed these record singles. Longer disks existed but only held some 4-5 minutes and were more expensive to make. Radio played the most popular music, so pop music artists were incentivized to create music that would fit within that length of time. The loose pop song format was created around that length. While technology has changed drastically and isn't limited to that length anymore, pop music generally still falls within that time limit because pop music still generally follows a similar format. Music - especially pop music - works very well in 8-bar phrases. [4/4 time]( URL_1 is the simplest, easiest to understand time signature, so pop music is mostly in 4/4 time. It also needs to be fast enough to be catchy without being hectic, hopefully right around the perfect speed to dance to, so somewhere between 100-130 beats per minute (probably 100 or 120). Presuming 8-bar phrases, *most* pop music is going to follow this format or something very similar to it: intro, verse, verse, chorus, chorus, verse, chorus, chorus, bridge, chorus, chorus, outro. That's 12 phrases at 8 bars, so 98 bars x 4 beats = 384 beats, divided by ~120 beats per minute = 3.2~3.8 minutes. Even more abstracted, the format goes like: intro, phrase, altered phrase (which has some discord, which creates tension), chorus (home key, which relieves the tension), repeat, outro. You're creating a musical story that follows the [story arc]( URL_0 ) where your verses (whether in the lyrics or the musicality or both) create the rising action and climax through tension and the chorus is the falling action and resolution. The bridge is the highest amount of tension and climax, then big climax into resolution with the final chorus and outro or fade or whatever. If you *really* want to get into music theory, which I am not good at, there are particular chords that are super common that pop music uses in each of these parts. And, of course, music is about repetition so it's not just one verse/chorus, you repeat it a couple times. The variations allow you to repeat the same music phrase so your brain recognizes it and likes it wants it but, WAIT, it's *slightly* different which is super interesting to your brain, and then hey look it's back to that same phrase I already know, whoo, brain is satisfied. That song length is also just about the right size to be interesting enough to keep people listening, but not long enough for them to lose interest before the next song comes on. Again, very digestible. Other genres of music don't follow quite as strict formatting as pop music so they may or may not have longer or shorter music. Pop music is designed to be easily digestible for the widest range of people. Most of those kinds of music don't end up on the radio, though. By the way, I'm not trying to shit on pop music for being formulaic. *All* music is formulaic to some degree. Some pop artists work with the limitations of the genre to be creative and make great music. Some pop artists use the format as a crutch to crank out lowest-common-denominator mediocre music. TL;DR: Records have a physical size limit and since the size of the record dictates how much music can be on it, there was a cap on how long a song could be and still be useful to radios. Musicians made songs to fit those records (which were ~3:30) and ever since then pop music has followed the same musical formatting, which means it lasts for roughly the same length of time.",
"Radio stations don’t want songs to be too long or too short. So for a song to be considered radio friendly artists will stick to this time limit. Billy Joel famously lampooned this with his song The Entertainer where he says even though song is catchy he won’t stay relevant anymore because the radio stations won’t play it."
],
"score": [
19,
3
],
"text_urls": [
[
"https://blog-cdn.reedsy.com/uploads/2017/07/climax-1.jpg",
"https://www.google.com/search?safe=off&sxsrf=ALeKk01P7aCKp1dIlJgvNkHQ-EFtYSu8ow%3A1610811679614&source=hp&ei=HwkDYPPEIua1ggeKuJbYCQ&q=site%3Areddit.com%2Fr%2Fexplainlikeimfive+time+signature&oq=site%3Areddit.com%2Fr%2Fexplainlikeimfive+time+signature&gs_lcp=CgZwc3ktYWIQAzoECCMQJzoFCC4QkQI6BQgAEJECOgUIABCxAzoICC4QsQMQgwE6CAgAELEDEIMBOgcIABDJAxBDOggILhDHARCvAToLCC4QsQMQxwEQowI6BQguELEDOgoIABCxAxCDARBDOggILhDHARCjAjoECAAQQzoHCAAQsQMQQzoICAAQsQMQiwM6BQgAEIsDOhQILhCxAxDHARCjAhCLAxCo"
],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kylscy
|
What is cloud hosting?
|
My dad has asked me to help move his business "on cloud" (whatever that means) and I'm having major trouble understanding all the terms given online!
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gjh29jn"
],
"text": [
"What this means is instead of hosting a website or data locally on a server located at your business, you instead use a cloud provider such as AWS, google cloud, or azure to host it or perform other services. Sometimes this is more expensive, it depends what you’re doing and what you already have. Billing can become really complex. Imagine something happens and a fire burns down your dad’s business and computers are destroyed. How quickly can he get everything back, including business records?"
],
"score": [
4
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
kynhw2
|
- What happens to the ash after combustion of trash in incinerators?
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gjhftu3"
],
"text": [
"Most of the incinerator bottom ash is being sold as aggregate and is used in the industry in a very similar fashion to rock aggregate. For example in concrete or asphalt or just as a filler material."
],
"score": [
6
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kynpuz
|
how are fingerprints not affected by variables like body heat/injury/pressure/etc to the point that we can solve crimes using them?
|
As the title says - I’m wondering how we can really use fingerprints accurately, when there could be so many variables which could alter your fingerprint, especially so that a partial print might be altered. Is it just based entirely on the ridges/patterns? Do they really not change much at all, even if you lose/put on weight, are really cold/too warm, damage your skin eg scratch or burn your fingertips, have been in the shower so your fingertips go all raisin-y, or you’re applying less pressure one time and more the next? Sometimes when I’ve been in the bath or have been cleaning or whatever I struggle to unlock my phone with my Touch ID haha, so I wonder how reliable fingerprints actually are.
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gjhhhcw",
"gjhh1se"
],
"text": [
"Actually, they are. I've heard tales of people employed in heavy hands-on work not being able to provide a fingerprint.",
"Some variables actually do affect your fingerprints. I accidentally burnt the skin on my right hand thumb, and my college biometric couldn't recognize my fingerprints, so I had to write a letter as an alternative."
],
"score": [
4,
4
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
kyojdx
|
Why do some hi-tech devices with fully-drained, permanent lithium ion batteries need some battery charge before working even when you plug them in?
|
I've noticed this with ipads and iphones. If it's completely drained and you plug it in, you still can't turn it on for a few minutes. I don't know if the battery is part of the standard circuit powering the thing or what.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gjho9sj"
],
"text": [
"The battery has to deliver a minimum voltage for the device to work properly. The voltage that a battery delivers decreases as its charge decreases, so if the charge is too low, the voltage will be too low."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
kyq8uf
|
What's the absolute minimum speed a plane has to go for it to stay in the air?
|
Physics
|
explainlikeimfive
|
{
"a_id": [
"gjhydhx",
"gjhyk1x",
"gji2oxe",
"gjhy2jk"
],
"text": [
"It's not really possible to give a simple answer to this - it depends on the plane, and on whether you mean air speed or ground speed. Against a strong enough wind, a light plane could fly while going backwards relative to the ground.",
"To stay airborne, an aircraft has to produce enough lift to offset weight. Lift increases with airspeed, and the angle of the aircraft to the airflow. If speed decreases, the angle must increase. If the angle increases too far, the wing stops producing lift, and the aircraft falls. This is called Stall. The speed at which is this happens can be determined from a pretty simple equation: V = sqrt( 2 * aircraft weight / (air density * wing area * maximum lift coefficient)) Where the maximum lift coefficient is the lift coefficient that occurs right before the aircraft stalls. Using this equation, you can calculate the minimum speed of any aircraft given it's weight, and the density of the air around it. I know equations aren't exactly ELI5 material, but that equation is easy to use, and answers the question for every aircraft, regardless of it's loading, altitude, and local weather.",
"The [Gossamer Condor]( URL_0 ), in 1977, flew a figure 8 course of a little over a mile and averaged between 10 and 11 mph on the course. I would guess that, at liftoff, it was going at a jogging pace, maybe 6 mph or so. So, it can be very slow, but this is getting down there at the minimum air-speed, I would think. You have to have some airflow over the wings to create lift. It depends on the aircraft. This one was human-powered. [You could ride a bike at a leisurely pace and keep up.]( URL_1 ) They later created the Gossamer Albatross that flew across the English Channel powered by a single human",
"For light prop planes, it's around 45 knots IAS, and it goes up from there. You can look this up for almost any plane, and it's called the *stall speed*. If you go slower than the stall speed, your wings lose laminar flow and stop acting like airfoils."
],
"score": [
24,
18,
6,
5
],
"text_urls": [
[],
[],
[
"https://airandspace.si.edu/collection-objects/maccready-gossamer-condor",
"https://www.youtube.com/watch?v=sp7yv67B5Sc"
],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kyqh3d
|
how does Ping work?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gjhzxov",
"gji0v7e"
],
"text": [
"Imagine that you want to see how fast the post office is, so you mail your friend a letter that says \"Hey - send this back to me as soon as you get it.\" As soon as you drop it in the mailbox, you start a stopwatch. When the letter comes back, your stopwatch says it's been six days, so your ping is six days. Internet ping is exactly that, only with an electronic signal from your computer to some faraway computer and back again. For most games, 20-50 millisecond ping is good, 100 milliseconds is getting too slow for fast-reaction games like shooters or Street Fighter, and up around 300-400ms even non-reaction games can get a little annoying. The word comes from submarine sonar, where you send out a sound pulse (which, inside the sub, sounds like 'ping') and time how long it takes to reach an object and bounce back, and the time interval tells you the range.",
"The command in a command line interface, or actual ping between computers/networks? I'll explain both, since they go hand in hand Command line interface : It sends a packet (a small piece of data) that says \"reply to me\" from one host to another, and measures the time it takes to receive that reply, or even says it never received a reply after a predetermined amount of time passes. Ping between networks/hosts : Information can only be sent and received at such a high speed, and when you have routers and switches moving that information around and processing it, it all adds a little bit of latency from initially sending the information from one device to another."
],
"score": [
50,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kyr3ah
|
Why are UFC and boxing matches the only mainstream sporting events where fans need to purchase PPV to watch it live?
|
Other
|
explainlikeimfive
|
{
"a_id": [
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"text": [
"These sports are organized in a kind of ad-hoc way. There's no structured \"season\" guaranteeing a certain number of fights at certain times. Instead, promoters organize events based on who they can get and when. It's difficult to sell that to a traditional TV network. They have schedules to keep and prefer to broadcast roughly the same thing every week. Instead, you sell each event directly to the public via PPV.",
"The problem with fighting matches is you cannot guarantee how long the match will last. So, it is very difficult to sell advertising to make the money you expect to get from the event. The Super Bowl lasts 4 hors, give or take, no matter what. So they know how much advertising they will be able to sell and actually show. Same with baseball, basketball, tennis, etc... A UFC fight might only last 1 minute into the first round. They won't be able to sell 100 30 second commercials in the amount of time that match lasts...",
"PPVs are such a weird thing. I think that never existed in Germany, but we don't even really use PayTV. Who would pay fucking 30€ for a 3hr Event? I have no clue how that works, who pays that? Not to mention you can probably easily watch it for free Online."
],
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46,
24,
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|
[
"url"
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[
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|
kyr6zd
|
Why do mirrors reverse left and right but not up and down?
|
Physics
|
explainlikeimfive
|
{
"a_id": [
"gjiait5",
"gji7rwr",
"gjidj3r",
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],
"text": [
"They don't reverse anything left to right (or up and down). You're thinking of a word printed on a shirt, and when you stand in front of the mirror it looks 'backwards' to you. It's your perception that makes it seem as though it's flipped around, but it's actually you who is flipped around relative to the shirt. To prove to yourself that things aren't actually flipped around, think about the rear-view mirror in a car. When you look in the mirror the driver in the car behind you is still on the driver's side of the car (i.e. on the left side of the mirror, if you live in most of the Americas or continental Europe). All the mirror is really reversing is *depth* relative to the mirror. Things that are closest to the mirror appear closer to you, in the mirror, than things that are further from the mirror. Here's a fun little experiment you can try at home, if you have something clear like a transparent plastic sheet to write on: write a word on that sheet, then hold it in front of you so that you can read it. It will appear in the exact same orientation in the mirror, and the mirror image will be easily readable to you too. Flip it around, as though you were wearing it on a shirt, and you'll quickly see why words look 'backwards' in mirrors.",
"Wear a shirt with some words on the front. Bend sideways at the hip so you're facing the mirror with your torso sideways. The words on your shirt will now be \"up and down reversed.\" The mirror will always reflect light so that the angle of light arriving (\"angle of incidence\") will equal the angle of light reflection. With pieces of yarn and some tape, you can even mark off the 3-D geometry between the letters on your shirt and the reflection in the mirror to show that there's no geometrical left-right tricks going on. Some people sum that up by saying \"You were the one who swapped the letters left-right, when you put the T-shirt on. You started off looking at the face of the shirt to read it, then you flipped it around before putting it over your head.\"",
"None of these is correct. The Answer is that mirrors invert things on the Z-axis, not X or Y. That is, they reverse things forwards and backwards. They *invert* rather than \"flip.\" Here's an excellent explanation. URL_0",
"The mirror doesn't flip anything. It reflects exactly what it sees. You are just used to seeing things flipped left-right because that is what happens in the real world when you face another human. They rotate 180 degrees on the Y axis to look at you."
],
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|
[
"url"
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[
"url"
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|
kyrati
|
why does salt melt snow on roads?
|
Chemistry
|
explainlikeimfive
|
{
"a_id": [
"gji6b3u",
"gji6g1f",
"gjihh9i"
],
"text": [
"It doesn't. The top layer of ice is continually melting and refreezing, so the salt doesn't actually melt the snow or the ice, it interrupts its ability to refreeze. [ URL_0 ]( URL_0 )",
"Adding salt lowers the freezing point of water by disrupting the hydrogen bonds that create the ice. It can still freeze in very low temperatures but most types of salt work pretty well 15-20 degrees below the freezing point.",
"Water molecules like to stick to each other, but they can also stick to other things. Heat makes them stick to each other less, but other things can do that too. When there's a medium amount of stickage to other water molecules, water is it's a liquid. When there's a lot of stickage to other water molecules, water is a solid (ice.) When it gets cold, that makes more stickage to other water molecules happen, so water freezes into ice. Water *really* likes to stick to salt tho. So when you throw some salt on ice, it decreases the stickage to other water molecules because it wants to stick to the salt instead. Since there's less stickage to other water molecules, it melts into water even though its colder than the temp it would normally freeze at if there was no salt to stick to."
],
"score": [
15,
7,
3
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"text_urls": [
[
"https://www.thoughtco.com/why-does-salt-melt-ice-607896"
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[],
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|
[
"url"
] |
[
"url"
] |
|
kyrrsr
|
Why do we burp babies?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gji9sat",
"gjics4z",
"gjjkanh"
],
"text": [
"Because babies tend to swallow a little air when they are nursing, and if we don't burp them, they may be in a bad mood because they have stomach pain, and they will spit up anyway but not on a burp cloth on your shoulder.",
"True story, My wife was 18 when we met and she didn´t know how to burp. She always had indigestion symptoms from trapped air and burping was a great revelation to her :)",
"Besides the whole, swallow air and get a tummyache thing that babies do, they also don't have the core strength/muscle tone to burp for a while after they're born; it's muscle that has get strong enough first even if it's involuntary."
],
"score": [
21,
3,
3
],
"text_urls": [
[],
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|
[
"url"
] |
[
"url"
] |
|
kys5nz
|
Why are there so many file formats for audio, video, and photos?
|
I know there are some formats that are for raw files, but most others are compressed. Why are there so many of those?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gjidy3f",
"gjieohl",
"gjihjfn"
],
"text": [
"[Relevant xkcd]( URL_0 ) Sometimes they serve different purposes. For example GIF and PNG are lossless formats so they are meant for graphics, while JPEG is a lossy format so it's better for things like photographs. Sometimes they're just advanced versions of previous formats, for example PNG is the successor of GIF, with better compression and quality. Sometimes they are just competing formats developed by different companies.",
"NB: lossless and lossy are terms used to describe the method the raw information is compressed. Some formats, like JPEG, actually damages the images...so you lose things like transparency, and get jagged edges on your lines From a photo perspective, raw files are determined by the camera manufacturer. Mostly because each camera company has their own way of processing image data. Keep in mind that raw files are actually just raw data tables that another program has to turn into an image. Camera companies used to saddle their devices with their own software, but now with Adobe being the industry standard, companies often just develop plugins than can be installed to make it easier to process the Data. Other formats like PNG (Portable Network Graphics) are used in graphics because it is lossless, meaning, each time it’s used/opened the information isn’t affected. So it comes in handy when working with graphics and/illustrations. It’s not great for photos since it’s colour profile is strictly RGB (red green blue) which makes it great for screens but not good enough for print; which is why TIFF (Tagged Image File Format) is used. TIFF is a lossless format that has some compression but without degradation and this is the format most print and photographers work with since the colours can be worked in both RGB (screen stuff) or CMYK (printing and paper stuff). After work is done all images and digital anything are often exported to JPEG which is a lossy format...since it’s designed to be on the web the compression puts more emphasis on size instead of quality. So to get the best JPEG you have to start with the best possible version of everything else.",
"These formats were all invented at different times in computer tech history, under different constraints. A lot of early image formats, were devised to go with a particular OS or computer hardware, and the format's colour scheme matched up with the colours that computer was capable of producing, etc. An early frontrunner as a standard was .bmp or \"bitmap\", which was supported by a wide variety of systems including Windows, Macintosh and Amiga It wasn't until the Internet started to become important, that interoperability and data compression began to matter - and, critically, intellectual property. In the early Internet, .gif and .jpeg were the two ruling image formats, and they used quite different types of image compression, and had quite different features. Like .gif could only encode 256 colours, but it could animate. .jpeg could encode millions of colours, but the compression degraded fuzzily and could make text look bad. And the patents to these formats were owned by different entities - and both of those entities required you to pay a licensing fee if you wanted to make and sell software which used these formats. And as time went by, the math and computing theory behind data compression was advancing, so people were exploiting newer techniques to get more usable info into less storage space the whole time too. It was the same with video formats. .mpeg and .avi and .mov (and RealMedia, and some others...) all came with different licensing expenses if you wanted to release software to play them. And the art and science of getting high-resolution video to compress well and look nice, well, there were a lot of approaches with quite different strengths and weaknesses. Around the early 2000s there was a big explosion of different software vendors releasing their own slightly-improved optimized codec as its own uniquely branded and licensed thing, and it became an interoperability nightmare. DivX and XviD were just 2 out of dozens of mutually incompatible and confusingly named formats out there. Various ['Codec Packs']( URL_0 ) started popping up, to try and give users an easy \"this should play most videos you ever find online\" bundle. Each of these formats had a company behind it fighting for market dominance, whereas people writing video player software for end-users, just wanted to be able to support everything without the user having to worry about it. So the end result is that we have a great big installed base out there in the world, of video and image editing software that can all read and write to a pretty big handful of well-known file formats, and a lot of those format wars are now old enough that the original patents have expired anyway. But that's the historical reason for having so many. It's just kind of the messy leftovers of a patent gold-rush."
],
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29,
8,
4
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"https://xkcd.com/927/"
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[],
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"https://en.wikipedia.org/wiki/K-Lite_Codec_Pack"
]
]
}
|
[
"url"
] |
[
"url"
] |
kysk7m
|
how do underwater flares (or matches) maintain a flame or light when they are surrounded by water?
|
Just watched Crawl (2019) and got me thinking. Edit: i should clarify, why do they not extinguish like a normal flame.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gjieugp",
"gjifvnn",
"gjj53yo",
"gjif1j4"
],
"text": [
"We're used to seeing fires that get their oxygen out of the air, but that's not the only way to do it. If you heat up a material with a lot of oxygen in it, like a sulfate, a phosphate or a nitrate, it can break down and release oxygen gas. So a mixture of, say, magnesium metal and some kind of nitrate, could keep itself going underwater. The nitrate breaks down and releases oxygen, then the oxygen helps burn the magnesium.",
"Anything which can sustain combustion underwater is able to do so because the three requirements for fire, namely a fuel, and oxidizer, and adequate heat, are present. For many fires, water is a good choice to extinguish the fire because it disrupts both the oxidizer and heat production. However, it is possible to create mixtures of substances which have adequate contact between fuel and oxidizer despite the presence of water and generate enough heat to continue the combustion reaction even though much of the heat is going towards boiling water. A typical flare that works underwater will have a finely powdered metal like calcium, aluminum or magnesium mixed with an oxidizer like a sulfate or nitrate compound, all bound together with some glue-type mixture. These reactions release a lot of heat and the flare has the oxidizer and fuel in physical contact and therefore the flare can burn underwater. There are also underwater cutting torches which work through a different mechanism, namely that they release high pressure shielding gas around the oxidizer and fuel gases to prevent the water from coming in direct contact with the flame so that the flame is not extinguished. ___ Simpler: Although the fires you're used to generally consume air, you can create fires that don't need air because they use a solid mixture of fuel and oxidizer. Those fires can burn underwater if they can produce enough heat to not be extinguished by the cold water.",
"To add on to the other replies, it's a similar reason to why rockets can still fire their engines in the vacuum of space; they bring their own oxygen with them.",
"A fire needs 3 things to burn: 1. Heat 2. Fuel 3. Oxygen Normally there's plenty of oxygen just hanging out in the air, so that one is a given. If you want an underwater fire though you've got to bring your own oxygen. So underwater flares are usually a combination fuel and oxydizer in a solid stick. Give it a good shot with a friction striker and you have everything you need for a fire!"
],
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3
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|
[
"url"
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[
"url"
] |
kysm8r
|
If I’m in the Southern hemisphere and I see the full moon, will someone in the Northern hemisphere see it too?
|
Earth Science
|
explainlikeimfive
|
{
"a_id": [
"gjifpmp",
"gjigfiv",
"gjifajb"
],
"text": [
"Yes, the phases of the moon depend only on the relative positions of the sun, moon and earth. The moon does appear \"upside down\" to people on different hemispheres though.",
"Yes, or at least mostly yes. The moon's orbit is relatively aligned with the Earth's so it's typically visible from anywhere on Earth each day for the same reason that daylight is. Since the phase of the moon is determined by the sun-moon-earth angle - which doesn't really depend meaningfully on the observer - you will generally speaking both be able to see the full moon. Now, if you are very close to the poles, it is *possible* that the moon will be above the horizon for one of you and not the other, even if it's nighttime for you both. But if the moon is south of the sun in the sky, it's possible for (a) it to be nighttime close to both poles, (b) the moon to be visible for one pole, and (c) the moon to be below the horizon for the other. But this can only happen very close to the poles, where no one really lives.",
"They could; it really depends how far you are. You could be in Ecuador, standing in the southern hemisphere, and someone three feet away from you could be in the northern hemisphere because you're both right next to the equator. :) In that case the two of you would be seeing 99.999% the same sky and you'd probably both see the moon. The further apart you get, the less sky you'd have \"in common\". My intuition says that somewhere between 90 and 180 degrees of angular separation you'd no longer have any sky in common, but I'm not sure I have the geometry skill to figure out exactly where."
],
"score": [
13,
4,
3
],
"text_urls": [
[],
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|
[
"url"
] |
[
"url"
] |
|
kystrn
|
How come we can find cures for up-and-coming diseases in usually less than ten years, but cancer has existed for so long and there still isn’t a reliable cure?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gjiggij",
"gjigh91",
"gjihd8e"
],
"text": [
"We very rarely if ever can cure a disease. We can develop preventative measures like vaccines, treatments like antibiotics or just treat the symptoms to increase comfort. But actually curing anything is quite difficult. We have lots of treatments for cancer already but because cancerous cells are so similar to the hosts it’s very hard to do anything that can kill them without also doing incredible damage to the person.",
"Cancer isn’t a disease as much a malfunction of your own cellular machinery. There are a number on control mechanisms which make sure cells don’t grow out of control, if any of these many mechanisms fail in the trillions of cells in your body, you potentially get cancer. Not all cancers are failures of the same cellular machinery. Not all cancers are equally treatable. The question is how do you get a medicine or therapy to target only the bad cells but not the healthy cells?",
"This is my first time answering on of these so I'll try to make it simple as possible. Cancer is caused by mutations that can come about in many different ways. Because the cause of cancer is so complex (with different genetic and environmental factors), it is much more difficult to treat compared to other diseases. Treatment is also difficult because each person reacts to the treatment differently and it can effect different areas/systems in the body. There is obviously wayyyy more information about this but this is the most basic explanation. Hope that help!"
],
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10,
9,
3
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|
[
"url"
] |
[
"url"
] |
|
kyt4at
|
There a only a handful of viable operating systems out there (Linux, Windows, and (?). What makes it so difficult to make a fresh operating system?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gjij785"
],
"text": [
"It's not. Writing your own basic OS is a fairly common computer science/engineering undergraduate assignment. But that's a purely academic OS that doesn't really do anything interesting and has zero applications. Writing a full-featured modern OS is the evolutionary tasks of hundreds of engineers working for years (potentially much more). It's not trivial so you need to have a really good reason to do it. The major consumer OS's (Apple, Linux, Windows) do almost everything that anybody wants for most applications. Specialized industrial OSs are absolutely a thing but you rarely see them outside their niche. It's like asking \"Why is it so difficult to make a new optical disk format?\" It's not, but there's a giant install base of Bluray players and they do almost everything anybody needs so you need a really compelling reason to get all those people to switch. It's a lot easier, most of the time, to just figure out how to do whatever you want to do on an OS that already exists. OS's also have many of the same core functions...once you figure out how to do that really well, where's the benefit in writing new code to do the same function over again?"
],
"score": [
11
],
"text_urls": [
[]
]
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|
[
"url"
] |
[
"url"
] |
|
kyte6q
|
Why does every building get dusty inside?
|
Earth Science
|
explainlikeimfive
|
{
"a_id": [
"gjikzdw",
"gjj2m45"
],
"text": [
"Because the people inside lose a lot of hair and old skin, dirt from outside gets blown in by the wind and animals (flies mostly, but also bigger ones) bring dirt inside. Dust is a mixture of all the stuff flying around and settting somewhere and is, at least i our homes, mostly made up of dead skin and hair.",
"Dust is primarily made of several things: dead skin cells, fungal spores, tiny fibers from clothes etc, loose bug parts, dust mites and other teeny bugs, and their poop (dust mite poop is what triggers dust allergies). It's pretty much impossible to keep them all out unless the room is hermetically sealed and no humans are left inside, which is not ideal for most buildings."
],
"score": [
8,
5
],
"text_urls": [
[],
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|
[
"url"
] |
[
"url"
] |
|
kytidl
|
Why are there no better alternatives for closing large wounds than stitches?
|
Stitching has been a thing for centuries (millennia?) and yet there still exists no other way to hold together a big wound, why not exactly?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gjilfq0",
"gjikx9g",
"gjikt37"
],
"text": [
"Staples, superglue, rubber bands...there's a variety of ways to close a wound. Stitches are generally cheapest and most effective, however.",
"Sometimes there is no better alternatives because what we have is good or the best we think we can make. There are staples that can be used, but usually not for large wounds. Stitches are very flexible, and they can be done inside and outside the body. They dissolve on their own sometimes. They can do multiple layers of stitches for deep cuts. There is a ton of reasons to use them. And while we have been using them for a long time, we have much better stitches now than we use to. Not everything in this world needs to be advanced. Some day we might have some space aged device that can close wounds instantly. But today we don't.",
"At the end of the day, the way you close a large wound is to bring the two edges of the wound closer together, so that the body's natural healing mechanism can get to work. \"Bring two edges closer together\" is a very simple goal, and stitches work very well to reach it. What \"other way\" would you think is possible?"
],
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10,
4,
3
],
"text_urls": [
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|
[
"url"
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[
"url"
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kytl8u
|
Why are there different variants of sign language? Couldn't one form become universal and be understood by all people regardless of language?
|
Other
|
explainlikeimfive
|
{
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"gjilock",
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"text": [
"This is the something attempts like [International Sign]( URL_0 ) have tried to address. Unsuccessfully. It turns out that getting all deaf people to use the same sign language is not much easier than to get everyone else one the planet to agree to speak Esperanto. The problems with getting people to discard what is often their native language for some nebulous benefit of being able to communicate easier with some other people very far away is that people for the most part don't want to. Language is culture and the deaf community in many places has been very protective of theirs. (Just look into the controversy about cochlear implants to get an idea of how passionate some people are about those issues.) It doesn't help that sign languages aren't related along the same line as the spoken languages that exist alongside them. American Sign Language, is for example based on French sign Language and rather different from British Sign Language.",
"Same reason there are variants of spoken language. Things like BSL (British sign language) and ASL (American Sign Language) evolved after the US had parted ways with the UK but before international telecommunications were invented, so evolved mostly separate. They each have their own, separate, hard fought, histories that I suspect many signers would be unwilling to give up. As a note - BSL isn’t “British English in sign form”, similarly ASL isn’t American English in sign form either. Sign languages often/always have a radically different language structure to spoken ones, including things like “spatial grammar” that doesn’t even really exist in spoken languages. In order to learn to read written English (in the case of people in English language countries) signers need to learn a completely new language - English - that is has almost nothing in common with their own.",
"That is the same reason we all have different languages. It's made up really long ago, all in their own ways. And if you ask them to all used the same language it's like asking a American to speek Japanese.",
"Because people from different regions developed sign language individually. A person's culture also plays into it - for example, some hand gestures that are rude in one country are not rude in another.",
"In the case Black Americans Sign Language, segregation forced African Americans to make their own language (they couldn't attend deaf schools, which were only for the white until relatively recently). I doubt the BASL community is interested in giving up their rich heritage for an international language that might lack some of the nuance their native signing does.",
"Because sign language predates VCRs, television, and the ability to wake up on one side of the planet and fall asleep on the other side. There was no convenient way to transmit the gestures of a visual language when sign languages were being developed, and there was little demand for a single international standard when it took weeks to cross an ocean. By the time we had steam engines or internal combustion engines, regional sign languages were already in place. No single sign language ever became an international standard for the same reason that Esperanto never really took off.",
"In general, it's because each was developed within a single country. International cooperation it the development of it did not occur.",
"I was told of this but in Australia the deaf use Auslan. And a woman went into the local school for the deaf and asked if they had an American exchange teacher working with them. They said yes why. Apparently a bus load of small children past her signing out the song Twinkle twinkle little vagina. LOL. Apparently the sign for vagina in Australia is the same as star in America."
],
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89,
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|
[
"url"
] |
[
"url"
] |
|
kytsql
|
Why is it so much harder to fall asleep when you’re thinking about how badly you need to go to sleep?
|
Yes I need therapy. Yes I’m working on it 😆
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gjiorf9",
"gjj7dpo",
"gjjqunw"
],
"text": [
"Going to sleep had two fases. First your body makes a chemical indicating you are going to sleep. It makes you more relaxed and it starts the production of another chemical that will cause the actual sleeping. If you stress, the first chemical won't be produced. That's because if you are stressed your body must be ready to fight off that lion or other danger. The second chemical needs you to be relaxed enough and don't have to much brain activity in your prefrontal cortex.",
"This is why bedtime stories are useful, they distract you from thinking about actively forcing yourself to sleep. Anyway, recorded books playing while waiting for sleep is helpful.",
"From an evolutionary perspective, being stressed makes your body get itself ready to respond to the stressor. The problem is that stressors used to be significant things, like stuff that could kill us. So our bodies fuel us with necessary shit to stay alert and survive. Our modern stress is a lot less hazardous, but our bodies don't recognize the difference. They just know stress, and they respond accordingly"
],
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34,
16,
4
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"text_urls": [
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|
[
"url"
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[
"url"
] |
kytze0
|
Why do we say people who hear voices in their head/feel people around them are insane and need meds, but religious people who say they feel and hear God are sane and go to church to worship it?
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gjiprub"
],
"text": [
"Because generally speaking, people who \"feel and hear God\" are speaking metaphorically. They aren't talking about literally hearing the voice of God speaking to them. Even the religious would agree that if you are literally hearing a voice speaking to you in your head, it is a sign of mental illness, even if you sincerely believe that voice to be God's."
],
"score": [
3
],
"text_urls": [
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|
[
"url"
] |
[
"url"
] |
|
kyu5oa
|
Why does lightning sometimes not strike the ground?
|
My understanding of lightning is that it is to solve an imbalance of electrons between earth & ground. If this is the case, why do some strikes hit airborne objects and such that can’t be “grounded”?
|
Physics
|
explainlikeimfive
|
{
"a_id": [
"gjiqh1i"
],
"text": [
"The ground isn't some magical thing. Charges that are imbalanced with flow to whatever so long as there are less charges there and they can spread out. They prefer to flow to an oppositely charged region, but neutral will do to as they can both become slightly negative (or positive) and spread out the charge more. Earth is quite a good neutral point, as it's very big and takes a lot of charge to make it charged. But if we're talking an airplane, the metal body takes this role instead. Lightning is the build up of charges in clouds. That's where the charges were exchanged, not with the ground. Most lightning is actually between clouds, or within a large one. Only occasionally does it discharge to the neutral earth. And this makes sense, the earth is neutral here. The clouds are positively or negatively charged, that's where the \"friction\" causing the static build up is happening, not on the ground. Only if a cloud has no oppositely charged cloud near by will it build up enough to strike the neutral ground, that's further away and not oppositely charged, it's a rare lesser alternative. You only think otherwise because it's the one you see, you don't see it within or between clouds, and if you do you're falsely assuming it the ground far away. Ground is so fundamental to the electrical power system, only because we make it so. One end of a generator or transformer literally has its wire attached to some copper rods driven into the ground. We chose to make the ground a wire in our electrical system. I think this is where the confusion about ground comes from. This is a human choice, not some fundamental behaviour that electricity always wants to go into the ground. Hook up one end of a battery to the ground and literally nothing happens, electricity does not inherently flow to ground."
],
"score": [
5
],
"text_urls": [
[]
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}
|
[
"url"
] |
[
"url"
] |
kyul4o
|
why do some gases, like oxygen or hydrogen form a molecule with a pair of atoms, while others like helium are just single atoms flying around?
|
Chemistry
|
explainlikeimfive
|
{
"a_id": [
"gjirxzw"
],
"text": [
"It has to do with the number of electrons available for bonding. The first \"orbital\" can contain a maximum of two electrons. The second \"orbital\" can contain a maximum of eight electrons. Helium has two protons and two electrons, and is happy all by itself. Hydrogen has one proton and one electron, so it bumps up against another hydrogen, and the two hydrogens share the two electrons, and they're both fairly happy. Oxygen has eight electrons total. Two of them are happy in the first orbital. Another four are fairly happy in the second orbital, and the remaining two choose to tango with the loose two from another oxygen. Or with two hydrogens. I can go into better depth, but this is ELI5"
],
"score": [
12
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kyuswz
|
How are documentaries about drugs where they interview drug dealers who wear masks to hide their identity made? How The National Geo or Vice, for example, get in contact with those people and why they agree to get on the camera and risk getting caught?
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gjiwnqc",
"gjivyl4",
"gjixgb5"
],
"text": [
"They likely hired a \"fixer.\" The fixer is often a local journalist, maybe just someone that just knows a lot of people and has a lot of connections and can introduce the journalist to the people they want to interview and extend their own reputation to the journalist. Fixers are crucial components of stories for foreign journalist. They're often a mix between translator, facilitator, driver, bodyguard, etc. Basically you'd have no chance at going and getting this story without first contacting a fixer who can make the right introductions for you and vouch for you. In other words there's almost certainly a middle-man between the guys doing the interview, and the guys being interviewed. They didn't just somehow cold-approach a big time drug dealer they had an introduction. As to why they do it? People love to tell their story to someone. People like it when people are interested in them.",
"They put some measure of trust in journalistic integrity -- that is, journalists guarding their sources. To be able to get first-hand knowledge and the real scoop is immense for a journalist, they would rather not compromise their chance at getting an exclusive story to turn someone in. That and if they mysteriously were found by police shortly after an interview, if they have connections it's possible the journalist may be put in danger since it seems they ratted.",
"There is no risk of getting caught. Those camera crews aren't going to arrest anybody. Journalists don't coordinate with law enforcement because doing that can get you killed and no story is worth getting killed."
],
"score": [
34,
12,
9
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kyv278
|
If we can have super potent versions of THC why cant we have super potent versions of CBD?
|
With synthetic cannabinoids we can have really strong THC why cant we have a synthetic version of CBD that's super strong?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gjj15b8",
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"gjix3c5"
],
"text": [
"Potency with THC is generally that the plants have been bred to have a higher percentage of THC in the bud. In 1970, the THC percentage was pretty low (like somewhere around 10%), today, you can get damn near 50% in a plant (numbers sourced from my ass). The chemical itself is the same, there's just more of it. That's what, on the whole, makes it more potent.",
"I think you are too confused as to just what synthetic cannabinoids are in the first place. The way this whole post reads, it seems you see it as a form of THC that is produced in a laboratory. This is not the case (unless you are talking about delta 8 thc, but even that is still natural as it lays in organic chemistry; we just speed up the process of obtaining a lot by converting CBD)... I digress, synthetic cannabinoids have very little resemblance to any naturally occuring cannabinoid just by chemical structure alone. Pretty much the only thing in common is/are some slightly similar psychoactive effects. So, it's not synthetically produced THC or CBD, at all! It's other completely different super cooked chemicals that just happen to kind of portray some of the effects of cannabinoids. Because of this, I doubt a synthetic CBD would ever get discovered much less even viable to our Earth's total chemistry possibilities. Hope this helped, if not, I'd be happy to try to clear it up some more. I guess it depends on how you define synthetics as well as cannabinoids but honestly, that still would not matter. They are not cannabinoids at all, but rather (mostly) ethyl and methyl indole chemicals. Even meth can cause some play on certain cannabinoid receptors in the animal brain; doesn't mean it replaces THC and/or CBD.",
"What would be the point? Chemical synthesis could make purified CBD, put the cost/benefit ratio isn't there."
],
"score": [
6,
4,
3
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
kywjte
|
- Why does putting the top on a pot of boiling pasta make it frothy and boil over?
|
Chemistry
|
explainlikeimfive
|
{
"a_id": [
"gjj48xw",
"gjj80qo",
"gjjr2m4",
"gjjofdj",
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"text": [
"The starch released into the cooking water stabilizes the froth that you get if you boil it too vigorously. Putting the lid on keeps more heat in so effectively it's like turning up the electricity or gas too high.",
"The lid traps heat and steam ~~, building a little pressure, which can lower the boiling point~~ . It may not be a lot, but can be enough. This then causes the pot to boil more, as it would if just cooked over a higher temperature. The frothy bubbles come from the starches in the water, giving a little extra strength to the surface tension. This doesn’t have anything to do with the lid, though. Edit: pressure increases increase boiling point, but pressure on stove top pot not likely to amount to much",
"Changing boiling-temp water into steam takes a ton of energy, at least as much as heating liquid water up to boiling temp. The phase change itself needs huge energy input. If the steam is free to escape, it carries all that energy away with it. If the steam is trapped by a lid, then when it condenses back into liquid it dumps all that energy right back into the pot. It's like doubling your element's heat setting!",
"This doesn't answer your question but put some butter or oil in the water to prevent this from happening...",
"With the lid on the vapor pressure of water in the limited atmosphere reaches its saturation point. Evaporation is now in approximate equilibrium with condensation. Without efficient evaporation there is no easy way for the system to shed heat from the burner. Water skyrockets toward maximum heat capacitance."
],
"score": [
168,
21,
15,
3,
3
],
"text_urls": [
[],
[],
[],
[],
[]
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}
|
[
"url"
] |
[
"url"
] |
|
kywk3i
|
Why/How do citrus segments stick together after the fruit has been unpeeled but can't re-stick after the segments have been separated? 🍊
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gjmedzn"
],
"text": [
"There's still little fibers between the segments you break when you pull them apart. Like sewing two pieces of cloth together with a couple of stitches of thread. You break the threads, the pieces won't stay together."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kywwbo
|
When they do the taste testing on cooking shows how do they ensure it's still warm and that sauces and stuff aren't congealed?
|
Other
|
explainlikeimfive
|
{
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"text": [
"The way I've seen it explained, they don't. At least on the Australian version of Masterchef. They walk between work stations, and taste it while in progress, but a lot of the time they've made up their minds beforehand, and the tasting is just for show. EDIT: /u/thechosenbum93 posted below citing the same place I read it, so I'm adding a link here. [ URL_0 ]( URL_0 )",
"It depends on the show. I know for Chopped, the judges are allowed to taste while the contestants are cooking, and immediately after as well. The dishes are kept warm until the on camera tasting which can be 30 minutes later or more. On Iron Chef, the contestants finish only one of each dish they make during the one hour contest, for the camera. Then they have additional time off camera to finish four more of each plate to have it ready just in time for judges tasting.",
"During the final tasting that we see on TV, the food is apparently cold. At least on the Australia version of Masterchef. Source: An article by Alice from S4 of Masterchef Australia - URL_0",
"I can confirm the same for the U.K. version of MasterChef. In fact for the first screen test you’re asked to cook the night before, bring it in cold then plate up while explaining the dish, how you cooked it etc directly to camera.",
"Most TV is fake. The impression of what the show is presenting happened - did not happen. It is true for virtually all shows. They make incidents or situations that did not occur to make it look like something did.",
"As others have stated, they don't. However (at the very least on the shows I worked on) you have to keep in mind that the whole thing is staged. The dishes are often cooked more than once and the tasting practically never happens right after the cooking. Most of it competition is done off camera, what you actually see (for both cooking and tasting) is for the audience's sake.",
"Short answer: they don't. Many times the contestant didn't even cook the dish the judges are eating. The cook-off and the tasting are done at separate times."
],
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"https://www.aliceinframes.com/8-things-you-didnt-know-about-masterchef/"
],
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kyxegf
|
why do we wake up earlier as we get older?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gjj9ahx"
],
"text": [
"As one gets older, we don't sleep as well. The part of our brain that determines our circadian rhythms (like our body clock) start crapping out. So your nighttime sleep will get shorter, but you take more naps during the day."
],
"score": [
9
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kyxitv
|
Why are there so many different ways to measure Radioactivity, and how do those methods relate to each other?
|
I have always had a hard time grasping this. Radioactivity has many units of measure: Grays, Rads, Rems, Curies, Roentgen, Sieverts, Becquerels. Why are there so many different unit types, and how do they inter-relate? I have a decent understanding of physics, but not in this specific area. To date I haven't read or heard an explanation that gives an "ah-ha!" moment or makes me quite understand what all these measures actually mean. Yes, I have seen the XKCD radioactivity chart.
|
Physics
|
explainlikeimfive
|
{
"a_id": [
"gjjdie5"
],
"text": [
"Most of these aren't units of radioactivity. Only Becquerels and Curies are. Radioactivity is a measure of how many atoms are undergoing radioactive decay each second. Rads and Gray are units of dose, which is a measure of how much energy (per unit mass) is being absorbed from radiation. This is important, because it impacts how both materials and cells react to radiation. Sieverts and REM are measures of biological impact from radiation. They tell us about how much cell damage and long term health impact is expected. Roentgen is a really weird unit that measures how much ionization radiation causes in otherwise stable materials, and ionization leads to funky cell chemistry."
],
"score": [
6
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
kyxjod
|
In ancient times and places where potable water was scarce and people drank alcoholic beverages for substance, how were the people not dehydrated and hung over all the time?
|
Edit: this got way more discussion than expected!! Thanks for participation everyone. And thanks to the strangers that gave awards!!
|
Biology
|
explainlikeimfive
|
{
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"text": [
"That is almost entirely a modern day myth. There were systems in place to ensure the town's water supply wasn't contaminated and drinking water in most of the world was perfectly fine. They even had a system where tanners and blacksmiths and such would be fined if their cast offs made it into the water supply and they were only allowed to operate in certain areas of town to keep the water supply clean. The laborer's DID drink a lot of ale and beer while working but it was because the alcohol content was so low that it kept them hydrated and helped give them calories to keep up their energy. It was more like medieval Gatorade than actual alcohol as we think of it.",
"Their alcoholic drinks were WAYYY less strong than today’s. A plain beer in history might only be 2-3% alcohol, with modern day beers 4-5% is standard on the low end, some get up to 8%. So, the dehydrating effects of their drinks really weren’t as serious. Also, in most cases, people still drank water, it was only really rare situations where the water wasn’t trusted in cities/urban areas. But even then, take Ancient Rome*, they built massive infrastructure (aqueducts) to bring water into their cities and into their fountains, fountains that people did drink out of. The idea that people never drank water is a fallacy. Edit: Rome not room Edit 2: there are many beers above 8%, I based my point on the most common brands I see, and maybe that’s skewed for me cuz I’m a poor American student who only gets Cheaper light beer. Also to those Belgians who told me that that’s Kiddo beer I’d love to try whatever y’all got goin on.",
"An important thing to point out is that it was never the alcohol that made the water safe to drink. To kill bacteria you need about 60-70% alcohol. The thing that made the water safe was boiling, which is a step in the beer brewing process. Tea or anything made after boiling water would have been safe too.",
"When you think of the kind of beer that people would drink all day, it’s nowhere near the alcohol volume that you’d expect from beer today - small beer back then was more like 1% abv. Many cultures that drank wine would dilute the wine with water to make it less harsh. So there were a lot of ways to minimize the amount of alcohol taken in while still using it to make water potable.",
"You can sustain your water hydration with a 5% beer easily if that is all you drink. Your liver won't like it, your kidneys won't like it, probably your stomach and digestive system but you can sustain off beer for at least 10 years so far....",
"Because they weren't drinking hard liquor 24/7. Beer and other alcohol was heavily diluted.",
"It's not a myth like the other commenter posted. I actually did a research paper on this, the answer is the alcohol content tended to be lower. Yes, typically running water and various water sources existed that weren't as dangerous as we think, but that wasn't true everywhere. People did drink beer/mead more frequently which was ultimately safer because the water is boiled as part of the process. It wasn't instead of water, which I think is what the commenter means, but it was certainly safer. They also found traces of tetracycline in vats from ancient Egypt, there is evidence to suggest it would have been anti bacterial as well. URL_0 URL_1 . Edit: clarification, grammar. If I find the paper, I'll post the sources. I'm on my phone.",
"People used to drink very low alcohol beer called small beer. Brewing removed the impurities. See URL_0 . Tea was drunk in the Far East for the same reason",
"I always wondered this. Wouldnt people just feel like shit everyday of their lives?",
"While a lot of what people have pointed out, lower abv ect., are true. A lot of the aristocracy, including the founding fathers, drank enough to make a frat boy question if it was a good idea. Workers where given given a small amount of alcohol in colonial times. And they would supplement that with stills. However, a lot of the landed gentry would have a solid buzz going at all times.",
"The word you meant was sustenance, btw, which is \"food or drink regarded as a source of strength or nourishment\". Substance would be the physical material that something is made of.",
"The small beer had a low alcohol content (around 1%) so it was more a liquid food than it was an alcoholic drink.",
"Just to add, beer generally has low enough alcohol content to not cause dehydration. Hard liquor though will dehydrate you",
"Well A: most water was fine and B: most beverages had very low alcohol content. Think Lemon, lime and bitters",
"This article theorizes that this might be a factor in the Enlightenment and Scientific Revolution. Once people switched from beer to tea and coffee, suddenly they were inventing all kinds of science, technology, and philosophy. Switch from a depressant to a stimulant and you get more ideas. URL_0",
"I'm a bit confused by your idea that in ancient times good water was scarce? Whatever gave you that idea? They had rivers, wells, cisterns, dams, lakes, ponds, reservoirs and springs. Ancient people weren't morons, they settled near water.",
"Just look up Small Beer. That's your answer. This thread is full of terrible misinformation.",
"In Colonial America they drank lots and lots and lots of beer. But beer could mean many things. They had their stronger stuff for boozing it up of course, but the daily drink was 'small beer'. Small beer was made with the remnants of a previous beer making batch of stuff. The grain and yeast was reused to make a much weaker, more watery beer that was drunk at meals, given to children etc. It wasn't exactly like they were drinking full on alcohol all the time.",
"I saw this one show. I believe it was south or maybe central Americans, and they would chew up these roots and spit the chewed up root into clay pots. Saliva contains enzymes that break down the root starches into sugar. About a week later they all gather and basically have a feast/party with this 'root beer'. Amazingly, it's not boiled or anything. They put a cloth over the clay pots to reduce contamination, that's it. Apparently it doesn't taste that great but it can get around 6 to 8 percent before the yeast dies. So pretty decent drink if you wanna get buzzed. This still occurs today. The host of the show got a hangover, but the aboriginals (iirc) seemed to really enjoy it. It was a special occasion deal, they didn't drink this booze daily."
],
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"https://www.jstor.org/stable/26057861?seq=1",
"https://www.sciencedaily.com/releases/2010/09/100902094246.htm#:~:text=develop%20therapeutic%20agents.-,A%20chemical%20analysis%20of%20the%20bones%20of%20ancient%20Nubians%20shows,practice%20nearly%202%2C000%20years%20ago"
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[],
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}
|
[
"url"
] |
[
"url"
] |
kyyrg0
|
How does mоnеу just lоsе or gаin vаluе?
|
I’ve never undеrstооd how monеу suddenly gаins or lоsеs its vаluе. I’m mоstly referring to The Grеаt Dерrеssiоn and that stосk mаrkеt сrаsh. How did mоnеу suddеnly bеcomе so wоrthlеss? It’s still mоnеу..? I do realize that monеу isn’t a “real” conсеpt and it was mаde up by humаns. I also just don’t know crаp about stосks. That’s all соnfusing to me. I felt like someone on reddit could give an anаlоgy or dumb it down so even I cоuld understand vаguely :D
|
Economics
|
explainlikeimfive
|
{
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],
"text": [
"If you have a five dollar bill, maybe today you can buy a good sandwich with it. That's your base price. Something for some amount. As time passes, costs change. People want more salary. Resources become less abundant or more difficult to get. Companies want more profit. Whatever the reason, it happens. In that sandwich example, maybe the cheese costs more. Maybe the company has to pay for new ovens for the bread. Fuel costs change, so moving ingredients cost more. Now you go to guy the same sandwich, maybe that five dollar bill isn't enough. Sometimes the opposite happens. Early today televisions cost much more than they do now. Through changes in manufacturing, availability of parts because of changes in demand, and recovering the costs of initial R & D, the same television money a few years ago gets more television today.",
"Inflation and deflation is the short answer. The total amount of dollars isn't static. It goes down because cash gets destroyed considering it's just paper. And it goes up when the Fed prints dollars and pumps it into society. If the amount of dollars increases, that means the value of an individual dollar goes down because there are more out there. This is why prices go up during inflation. I personally really liked the book Naked Currency. I thought it was a good eli5 book on what money is."
],
"score": [
4,
3
],
"text_urls": [
[],
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|
[
"url"
] |
[
"url"
] |
kyz4sf
|
If you haven’t eaten for a while and you finally eat why do u feel immediacy better and like u have more energy even though the food couldn’t have been absorbed into you body yet ?
|
Biology
|
explainlikeimfive
|
{
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],
"text": [
"Because your brain lies to you. As the time between meals grows, your brain starts freaking out. It doesn't know the next time you are going to eat. You might not eat again. It begins sending hunger signals. You need to eat. You NEED to eat. I'M RATIONING ENERGY BECAUSE WE MIGHT RUN OUT! And then, ahhhh, a bite of food goes into your mouth. Your brain realizes it was being so silly holding onto all that energy and signals your body thats it's ok to begin burning fuel at a normal rate again. The sugar receptors in your mouth let your body know that sugar will begin coursing into your bloodstream and filling up your energy stores in the next few minutes. Death averted...for a few more hours! There is a great early episode of Radio Lab about something similar. [ URL_0 ]( URL_0 )",
"Simple carbs like white sugar start hitting your bloodstream pretty much as soon as you put it in your mouth. Other than that I'd suspect that the effect is psychological and that you associate the action of eating with a feeling of well being.",
"All food is basically made up of primary food components like carb, protein and fats. The simplest and the most effective way for our body to gain energy is by consumption of glucose. When you eat after not having eaten for a while, the trace amount of glucose gets rapidly absorbed and is used to help make you feel better. And absorption of smaller monosaccharides like glucose can take place in small amounts in the oesophagus as well so the food doesn't even need to reach the stomach. So some glucose is used to make you feel better while the remaining food is still being digested by the body.",
"Simple carbs/sugars go straight to your body's brain and quickly add energy. When eating, your body releases something called Ghrelin, , which tells your body that you have eaten food and you hunger is being fulfilled. That feeling will last for a while (because of the Ghrelin),, but soon will fade if your food doesn't contain enough other nutrients(fat, protein, ..)"
],
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123,
14,
8,
3
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"text_urls": [
[
"https://www.wnycstudios.org/podcasts/radiolab/episodes/91709-limits"
],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kyznmp
|
What is Queer?
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gjjnsaq",
"gjjoou1",
"gjjobdl"
],
"text": [
"Queer just means strange or unusual, and it be some a slang term for someone who was gay. It just means strange or unusual and not at all an offensive term.",
"Queer is a broad term that covers LGBTQ+. It used to be used as a derogatory term and now people in the lgbtq community have reclaimed it, so it is really just another word for lgbtq+, but generally more used by people in the community as opposed to cis/straight people.",
"Not for gay people, queer is another term of one's sexual identity. Me like most other gay men would use the term gay to describe myslelf but a lot of people started using queer. I have yet to figure out what being queer actually is among my community, nor do I care enough about that community to go find out."
],
"score": [
3,
3,
3
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"text_urls": [
[],
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|
[
"url"
] |
[
"url"
] |
|
kz02e8
|
What exactly is a Boltzmann brain?
|
I've tried and tried to understand it but there so much to follow, I can't grasp it in its entirety.
|
Mathematics
|
explainlikeimfive
|
{
"a_id": [
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],
"text": [
"It's an indication that something is wrong with your theory of physics. There are several different boltzmann brains, but probably the easiest to explain is the original. The other versions are broadly similar, but pop up in relation to different theories of physics. So, anyway: the original Boltzmann brain starts with a pretty basic and important question, namely \"why is the universe as we know it here?\" At the time, nobody knew about the Big Bang or the expansion of the universe, and the going scientific theory was that the universe was eternal and unchanging. But if that was the case, it should have long since reached as state of maximum entropy...a \"heat death\" where everything was just a haze of evenly distributed atoms with no stars or planets or anything. That's kind of a problem since there are stars and planets and everything. However, it's also known that entropy is _probabilistic_. If you take puzzle pieces and shake them in a box, they are going to just get more and more jumbled...get closer and closer to that \"heat death\" of perfect randomness. But if you shake long enough hypothetically all the pieces _could_ bounce back just right to form the puzzle again. So the original idea for how we could have the universe is that, over long enough time, the universe just sort of happens to bounce its way out of heat death and back to a low entropy state, and that's the universe that we see. It's _staggeringly_ unlikely, but if you have an infinite universe and infinite time, why not? This is the \"Boltzmann universe\". ...But..then someone pointed out that, while still staggeringly unlikely, it's much easier to just spontaneously generate a brain that thinks a momentary thought than an entire visible universe, in the same way that if you are bouncing around a puzzle box it's much easier to bounce together a couple pieces to make a guy's head than it is to bounce together the whole puzzle... and in fact you should bounce together random heads a huge number of times compared to bouncing together entire puzzles. So any theory which relies on random entropy reduction to generate an entire universe has the problem that anyone in the universe is far more likely to be one of those two puzzle-piece heads than a part of a fully built puzzle. This is contradictory and absurd and rather implies that there's something fundamentally wrong with the theory. ....and indeed, later observations showed there _was_ something fundamentally wrong with the theory, namely that the universe is not eternal and unchanging but instead is expanding and only a few billion years old. As a result, no highly unlikely entropy fluctuations are needed and thus there's no implication of zillions of boltzmann brains for every actual universe. Now, even current theories sometimes spit out boltzmann brains under different situations but if you ask me, that just means we don't know all there is to know about the universe yet.",
"It's just a brain produced by something random; usually quantum fluctuations or \"nucleation,\" depending on what \"kind\" of universe we really live in (i.e., the true fundamental properties of the universe). But other than that, it's literally just a brain. The problem is: how do we know we're \"real\" humans versus just a brain that spontaneously assembled? If the universe exists for infinite time and under certain circumstances, there would be infinite Boltzmann brains. So the probability you're an actual human is basically 0: you're probably a Boltzmann brain with spontaneous memories of being a human."
],
"score": [
4,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
kz0fma
|
How our fingers get those little skin tags around the nails and why they don't just tear off easily/why they are so painful to remove.
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gjjvfwf",
"gjk4s5o",
"gjko84i"
],
"text": [
"They are called hangnails. Don’t tear them off. Trim them with nail clippers. The little slivers will not hurt when you cut them, but they hurt like hell if you tear them out.",
"Literally nobody actually explained anything instead they made fun of OP for doing something they didn't even know was wrong.",
"Might be wrong in a few details. The outer layers of skin is dead skin that is built up as a protective shield and is continuously replaced as it in worn out. Those outer layers are normally kept moistened by your blood and body oils, but can also dry out rather easy. The finger tips dont have a good means to keep moist being so far from a blood supply, so they often dry out. And next to a finger nail that skin isnt likely to be worn off before it drys, and cracks. Once it cracks that crack will go in any path it can till reaching moist skin. Those paths being your finger prints and the moist skin being the living stuff. By ripping out a hangnail you are ripping a hole in your skin. That's suppose to hurt. Cut them off instead with nail clippers, a knife, your teeth, or pinching with the other hands nails. Its a perfectly normal as well. Moisturizers can help prevent hangnails, but you're stuck with them for life like all of us."
],
"score": [
9,
5,
4
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kz0xzs
|
What is space made out of? What is the blackness in space?
|
Physics
|
explainlikeimfive
|
{
"a_id": [
"gjjv8my",
"gjjvh6s"
],
"text": [
"Blackness is just the absence of light. Because light to our knowledge only stops once it hits something or is diverged through smaller particles it passes through, it is \"absorbed\" by these things. Space is so vast and so there's always going to be darkness because of how light ultimately travels. As for itself, space is filled with remnants of many elements that were released in the big bang. There's also the ongoing discussion of dark matter, which is potentially a form of gravity that exists.",
"As for what space is made out of, I don't know. It's basically just a volume in which matter and energy can exist. Especially when combined with time as a fourth dimension, it has been described as a \"fabric\" because things behave differently depending on where they are, leading us to believe it has a slightly non-uniform structure. But what is the blackness? Simple: the absence of light. There's a negligible amount of \"stuff\" in a given volume of space, and deep space appears black because there's no discernible light coming from that direction. The sky is blue on earth because the sun's light gets scattered and becomes ambient, but in space, if a light isn't shining directly into your eyes from the source or from a reflection, you can't see the object. So a lot of it appears black."
],
"score": [
4,
4
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kz1s6n
|
how do we know the universe is expanding? could it not be that light from galaxies at the "Edge" of the galaxy is only just now reaching earth?
|
what the title says. I know enough about space science to know that but not enough for big equations and stuff, which is why i'm posting this here
|
Physics
|
explainlikeimfive
|
{
"a_id": [
"gjk01y4"
],
"text": [
"It's not just that we're starting to see things that are farther out in space. Things are moving away from us, which kind of actually makes it look like we're the centre of the universe. However we've noticed that no matter which point of space we look from, things are always moving away from us. The literal \"space\" between everything in the universe is expanding. As a visual example you could draw dots all over a balloon and start to blow it up. That's probably the best explanation you're gonna get from me using my very limited knowledge aha."
],
"score": [
6
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
kz2l8c
|
Why can't we live forever if we keep transplanting new/younger organs
|
If a person keeps transplanting new / younger organs (Let say every 10 years you replace one part). I understand there's compatibility issues but barring that is that technically not possible? Or does our brain literally just shuts down after time as-well?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gjk55rx",
"gjk4as0"
],
"text": [
"On top of people pointing out you can't replace the brain, there are far more problems to this. The entire body is subject to wear and tear, not just the organs contained in your torso. Your joints, skin, circulatory system, *everything*. Replacing these isn't possible. Also, having even a single transplant means taking immunosuppressive drugs for the rest of your life to prevent/delay rejection or graft vs host disease. The level of suppression you'd need to deal with an almost entirely transplanted body would make you liable to die from a common cold.",
"No. Even if somehow you were able to transplant a brain, you would lose all of your memories. The brain is the only irreplaceable part of your body. Lungs heart and kidney can be replaced. However, your brain contains your whole life on it. It’s like a save file. You’re suggesting to take out the save file and put in your friends. You would forget all about yourself and you would basically become the person whose brain you put in. In conclusion, the only way this might be possible is if scientists find a way to put all of the information from your brain into an artificial brain."
],
"score": [
17,
5
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
kz3elr
|
Why does our stomach start to have intense pain after not eating for a long time?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gjk9x9p",
"gjkcqw9"
],
"text": [
"The human body is amazing, if you don’t eat it knows you need energy and creates hunger pangs. These are contractions of the stomach as a reminder to eat. In the modern world it can also be boredom or a sugar craving due to poor diet.",
"It's basically just your stomach yelling at you for food. Our bodies aren't very good at communicating with us, the best most parts can do is cause pain as a \"something's wrong\" signal. Stomachs have a better vocabulary, they've got nausea and hunger pangs as well, but if you ignore those then all that's left is pain signals. It's also worth noting that your stomach is a bit silly and can't actually tell if you need food. It starts saying \"I'm hungry\" when it means \"I haven't eaten in a while\" or \"don't I usually get some food about now\", and it'll start hurting as if to say \"we're starving to death\" when what it really means is \"I'm empty, and I'm not used to that\". We can go a lot longer without food that our stomachs would have us believe."
],
"score": [
7,
5
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kz3gpe
|
why does brain damage results in people having depressive disorders, raging attitudes, etc etc?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gjkbtfa"
],
"text": [
"The front part of your brain, just under your forehead is the prefrontal cortex. This part does A LOT of things, it kind of relates to everything, including self control, planning goals, personality and social behaviour. As you can imagine, when you get head trauma, that part of the brain gets hit against the skull and causes damage. That means all things the prefrontal cortex helps with don't work like they should, so self control is limited which makes the person easily get angry or impulsive and so on."
],
"score": [
4
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kz3lj6
|
If sound waves travel by pushing particles back and forth, then how exactly do electromagnetic/radio waves travel through the vacuum of space and dense matter? Are they emitting... stuff? Or is there some... stuff even in the empty space that they push?
|
Physics
|
explainlikeimfive
|
{
"a_id": [
"gjka6yt"
],
"text": [
"Electromagnetic waves are waves in the electromagnetic field. A change in the electric field induces a change in the magnetic field and vice versa. If you set up your fields in just the right way you get an oscillating electric and magnetic field which propagates outwards, this is what an electromagnetic wave is. The electromagnetic field permeates the whole universe and so light doesn’t need a medium to exist in because it’s just an oscillation in these fields."
],
"score": [
10
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kz3loj
|
What is space made out of? What is the blackness in space?
|
Physics
|
explainlikeimfive
|
{
"a_id": [
"gjk93tv",
"gjk95ig",
"gjk983e",
"gjkd5d7",
"gjk9zro"
],
"text": [
"Blackness is what we see when no light comes from a place. If a region is empty, and no light comes from it, then it must appear black. Only if a star is on the other side of the space will it appear lit. Space is 'made of' emptiness.",
"Space is made out of, well, space. A bit lacking I know but if you take a glance out of your window the air between the first thing you see and you is basically just air. Now remove that air and every other gas and take away the light from the sun and tadaa you basically have space. Space is a vacuum filled with all kinds of radiation is so vast that between stars can be thousands of light years. And since stars are almost the only thing that produce light out there the entire rest remains dark. Edit: the blackness in space is the absence of things we can see.",
"Space isn't made of anything, it's the absence of matter we call 'space'. Space is black, simply because there's nothing for light to reflect off of.",
"Roughly 68% of the universe is dark energy. Dark matter makes up about 27%. The rest - everything on Earth, everything ever observed with all of our instruments, all normal matter - adds up to less than 5% of the universe.",
"Space is mostly just.. empty. There's almost nothing there. Just single atoms of gasses and some lone particles swishing around. Maybe some dust here and there. The blackness is really hard to explain to an actual five year old. Normally our night sky would be bright, because there's stars in every direction. And they still shine on us. But they are so far away that the space expansion between those galaxies and ours is faster than the speed of light. So the wave length of their light gets stretched so extremely, that it isn't in the spectrum of visible light anymore. So our eyes can't detect it. By the time it reaches us, it is lower frequency electromagnetic radiation, such as UV, X- or even gamma rays."
],
"score": [
5,
5,
4,
3,
3
],
"text_urls": [
[],
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kz3nd7
|
How do video compressors work?
|
I've been using a video compressor under 8mb for discord videos and I've been wondering, how do they work?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gjk9zb4"
],
"text": [
"By getting rid of information that isn’t too important. There are two types of video compression, intraframe and inter frame. Intraframe works like image compression, it looks at each frame of video and tries to reduce the information it needs to store. For example if the image is of the night sky, instead of storing the very low brightness of each black pixel it can just say ‘all of this group of pixels are black’. You lose some information because they likely weren’t all exactly the same colour but it’s close enough. This loss of information is why highly compressed images or video have blocky patches of colour. Inter frame compressions is also important, storing every frame of video would take gigabytes of space for even a short HD video. Instead we start with a frame and then store what transformations need to happen to get each new frame. I.e if someone is waving then you don’t need to store the entire image every frame, just store it once and each new frame the video says to move the block of pixels corresponding to the hand by some amount. Every now and again we need a new frame but doing this can cut down the file size by an order of magnitude. Your compressor is likely doing both to the video file, increasing the space between stored frames and also compressing those frames."
],
"score": [
5
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
kz4cj4
|
How come balloons are so good at collecting electrons if you rub them on your hair, even though rubber and similar materials are generally terrible conductors for electricity?
|
To me it makes sense that if a material is really good at collecting electrons, it should also be a good conductor. but that's clearly not the case. Why not?
|
Physics
|
explainlikeimfive
|
{
"a_id": [
"gjmfjf2"
],
"text": [
"The static generated by rubbing a balloon only occurs because the balloon is an insulator, otherwise the charges would be able to flow freely around the balloon and the local concentration of electrons would dissipate. The balloon is able to collect electrons because the molecules have a high electron affinity, meaning they accept additional electrons and bind them into the molecular structure (so they aren't free to move)."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
kz4eve
|
What are SPACs in finance and why are they so popular recently?
|
Economics
|
explainlikeimfive
|
{
"a_id": [
"gjkjcwa"
],
"text": [
"SPACs are a trick to speed up an IPO of a company. I’m sure you probably are aware of an IPO, when a company initially puts shares on the market and “goes public.” The problem is that for the owners of the company, this has heavy regulation attached to it and constant delays. It takes a while to take a company public through an IPO. Most companies have a lot of assets and statements they have to sort out and publicize before they go public. An SPAC is a bit of a cheat around this system, cheating the regulations by making the IPO look like company acquisition. The idea is that some kind of trusted person on Wall Street creates a new company and takes it public immediately, these companies have no assets and no employees, none of the messy stuff that causes delays in a common IPO. The funds raised from the IPO are then used to buy a company, or at least a large share in the company.The SPAC in effect converts itself into the company. The reasons for their popularity is pretty clear here of course, it’s just faster. The SPAC already likely exists as a public company for when a private company wants to go public, so it just has to negotiate the sale. The sale has significantly less regulations on it. The initial investors in an SPAC actually have no idea what the SPAC will end up as. Investing in the SPAC itself is risky, but later on its less so. There is an element of trust of the executives, though the executives have also put in much of their money into the spac so you can trust their interests align with yours. Typically they were considered sketchy because of course they are bypassing the traditional IPO regulations. But apparently people have been viewing them as more of a burden recently than something protecting investors."
],
"score": [
4
],
"text_urls": [
[]
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}
|
[
"url"
] |
[
"url"
] |
|
kz4ij7
|
Why does humans’ ideal body temperature (98.°6) not make us feel like we’re burning up?
|
If it was 98.6° outside, anyone would be hot and sweating like crazy.
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gjkgbqi",
"gjkgfdm"
],
"text": [
"Because our bodies give off heat by moving around and doing other stuff like digesting food. If we are somewhere hot, we can't lose heat as easily, meaning we get hot and uncomfortable. The best temperature that allows us to lose the right amount of heat is around 20C / 70F",
"You feel like 98 is hot because at that point you body looses all ability to cool. And you body is constantly generating heat that has to be released to the outside or you would overheat."
],
"score": [
15,
6
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
kz570u
|
Why does time feel like it goes by fast when we sleep?
|
8 hours go by yet it feels like only a few minutes went by when sleeping. Why is this? Does the brain make you not remember time when sleeping?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gjl3frn",
"gjl72n8"
],
"text": [
"Most people are good at estimating the time that's passed while they've slept. The only reason it feels it goes by quickly is because you're not conscious. In other words it's no different than time passing by quickly when you're not always checking the time doing other things.",
"Your perception of time is based on your memories and experiences. When you are asleep, you are making no memories and having no experiences, so no passage of time is being recorded. This is also why people with amnesia won't be aware that any time has passed during a chunk of time that they forgot about. And no, your brain doesn't make you not remember, because there is nothing to remember. If you turn a video camera off and it doesn't record anything does that mean you went back and erased the stuff it wasn't recording? No, it just didn't record anything because it was off. You were asleep, so your memories recorded nothing."
],
"score": [
8,
7
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
kz6kau
|
What is the difference between being brain dead, and being in a vegetative state?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gjl8fuv",
"gjl2wfr",
"gjl6x31"
],
"text": [
"Brain dead comes with a declared time of death. There is no neurological function within the skull. On an exam a patient is without the ability to construct the pupils, move the eyes, cough or gag when a breathing tube is wiggled. The most protected part of the brain is the brain stem. It controls breathing. In brain death it no longer functions. (I can explain an apnea test later if desired) Another test used to confirm brain death is a brain flow study. Contrast dye (very mildly radioactive) is injected into the blood stream. If imaging shows there is no blood going to the brain you have brain death. Brain death is irreversible. The media often uses the term poorly creating confusion. If they “woke up” then they never were brain dead. Source: Years of practice in organ transplant. Now in palliative care. One of my patients was declared Friday.",
"With a vegetative state, there is some brain function going on despite the coma. However, brain dead = no part of the brain is functioning.",
"Brain dead is dead dead, very little to no brain function, there’s no coming back from that Vegetative state, there’s function there and a chance you might wake up one day"
],
"score": [
16,
3,
3
],
"text_urls": [
[],
[],
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}
|
[
"url"
] |
[
"url"
] |
|
kz728u
|
How does lactic acid cause muscle fatigue and why+how do we produce lactic acid?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gjl9wte"
],
"text": [
"Lactic acid is a byproduct of anaerobic energy production during intense exercise. Anaerobic energy production occurs when there is inadequate oxygen. Further, build up happens when the production of lactic acid overshoots the ability of the blood to carry it away. Lactic acid buildup lowers the local pH (from usual 7.4 to 6.4-6.6) interfering with a number of biochemical reactions necessary to generate energy for the muscle. No energy = muscle fatigue. The change in pH is also responsible for the characteristic burning feel."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kz7g9v
|
why does Lithium batteries get less efficient after a while?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gjlryk7",
"gjm6628"
],
"text": [
"This is a general property of all batteries. Batteries depend on what’s called an equilibrium or a reversible chemical reaction. In theory the reaction should be able to cycle indefinitely. In reality, every cycle causes some degradation in the geometry of the battery. In the case of a lead acid car battery, an electrode may literally break in half.",
"Batteries produce electricity via chemical reactions. Rechargeable batteries have 1 or 2 chemical reactions that are \"reversible\" meaning that if you put electricity into the battery (charge it), everything will happen perfectly in reverse. However, the chemicals inside the battery don't JUST have 1 or 2 reactions occurring. In reality, there are likely over a dozen different reactions that can occur within the battery. The manufacturer has done their best to prevent the other reactions from happening though, because these other reactions are undesirable. They are NOT reversible. Meaning once they occur, they change something inside the battery permanently. (The reversibility of a chemical reaction has a lot to do with energy transfer. If a particularly stable product is formed, it's extremely hard to break that product apart again, and if you tried, you'd ruin other components of the battery.) There are reasons why these reactions exist, of course, but that's beyond the scope of ELI5. Think of it like this. Imagine a water filter. Water can flow through one way, and it can be forced out the other way to \"clean\" the filter. But occasionally, whenever you do that, a little tear forms somewhere inside the filter or a piece of debris CAN'T be forced out of the filter. As that happens over and over again, eventually the filter is going to be less effective, right? The same thing happens with batteries. You use the, you charge them, etc. but occasionally \"side reactions\" occur that degrade the \"health\" of the battery and make it have less charge overall."
],
"score": [
6,
3
],
"text_urls": [
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}
|
[
"url"
] |
[
"url"
] |
|
kz88kk
|
When a ball dropped from a height hits the ground, where does all the kinetic energy go?
|
Physics
|
explainlikeimfive
|
{
"a_id": [
"gjlm2xw",
"gjlmbo4"
],
"text": [
"Some into deformation of whatever the ground is made of, some into an extremely small change in velocity of the earth, some remains in the ball if it bounces, some into sound energy if it makes noise on impact and some into heat due to inefficiency .",
"When you raise a ball to a certain height it has potential energy. As soon as you drop it, it starts gaining speed. Over time the potential energy is converted to kinetic energy as it gets closer to the ground and speeds up. When it hits the ground, energy can be dissipated in many ways. If it's a rubber ball, some kinetic energy is converted to elastic potential energy as it compresses, then that elastic potential is converted to kinetic energy again as it bounces back up. Some energy is dissipated through heat, some through sound."
],
"score": [
33,
13
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kz8985
|
Why does current prefer to go to the ground from a live wire if the ground is made of tiles and dirt which are resistive materials?
|
If I supposedly touch a live wire while standing on ground with no insulation beneath feet, how does the ground(which is made of tiles and dirt) offer less resistance to current than my body?
|
Physics
|
explainlikeimfive
|
{
"a_id": [
"gjm1eon",
"gjm2omo"
],
"text": [
"I'm not sure what you're asking here. If you touch a live wire while standing on the earth (including on ceramic tiles), some amount of current, which is determined by the voltage, will pass through you and through the tiles into the Earth. In order to calculate how much current would pass from a voltage source, through the person, through the tile, to the ground, you absolutely would need to consider the resistivity of the ceramic tile. That's how insulation works. As to why the ground is considered to be at zero volts, it's because your electrical system that's delivering the voltage is grounded as a voltage reference, by literally driving one or several copper rods into the ground to provide extensive electrical contact between the ground and the electrical system. Because the ground is enormous, it can be treated as an effectively infinite current sink. It can accept any amount of current without driving a voltage increase. This is less true as the current and voltage go up, and a high voltage line in contact with the ground absolutely causes the area around the contact to be at a higher voltage relative to the rest of the Earth.",
"The ground is actually a pretty good conductor, usually. Even if it doesn't have great conductivity, it has great conductance simply due to how big it is. Putting two equal resistors in parallel halves the resistance, and the ground is a lot of resistors in parallel. A continuous spectrum of parallel paths. It has low resistance due to its size. That said, you're right. Sometimes the exact connection point to ground can be lacking. If only a small surface area is in contact, that serves as a bottleneck. The ground at times can be a bad conductor. It depends a lot on the ground composition and the water content. Damp soil and clay can actually be very good conductors. It's not going to be anywhere near copper or aluminum obviously, a #4 wire made of clay is going to be shit. But it's not a #4 wire made of clay, it's the ground. It's massive. Even a cubic metre of wet clay is going to give you a pretty low resistance. Dry rocks might not be a good conductor, and in those scenario grounding things is a little trickier. But don't let that fool you into thinking a concrete slab or tile floor sitting on some soil is an insulator, it's not. It's not rubber. There's some moisture in there, it will somewhat conduct. 120V household might find a way for a decent amount of current through it, potential enough to kill you, that doesn't take a lot. > 25kV line definitely will drive enough current into the ground to kill you, and potentially kill you just for standing on the ground near that point with your feet spread far enough apart. As for why a live wire would want to travel to the ground, it's because the other end of the generator or transformer is connected to the ground. Sometimes just as simple as driving a long copper rod into the ground and attaching a wire off the transformer to this, sometimes you can just use a buried metal water pipe instead, sometimes a more involved grounding system is needed if the soil conditions are poor. Regardless of how, we've set the ground up to be a potential wire back to the source. Compare this to a car, where the negative battery terminal is connected to the frame. As such, the frame always acts a return, any wire connected to the positive terminal making contact with the frame will short back to the battery. When you boost a car battery, you're not even supposed to put the negative clamp on the battery itself, just the frame (to avoid the sparks at a battery potentially off gassing hydrogen). We do the same with the electrical grid, but with the ground instead of the car frame. Why do we make the ground a path? It gives the system a reference point, because the ground (or metal car frame) is everywhere and a good conductor, it defines the common 0V point itself. Why we want the electrical system to have a reference point? Without ground it would be floating, dangerous and unstable. We sometimes even want to use it as a wire, there's some power lines out there that use the ground itself as the second wire. High voltage DC lines will sometimes do this, and power service to remote farms is often just a single live wire. This is why a live wire will flow to ground, if given proper contact. It's a path back to the source and a half decent one at that. Not as preferable as say another wire phase itself, but better than an open circuit and comparable to or less than a load like a motor or light bulb."
],
"score": [
4,
4
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
kz8m7s
|
- How is it that people fall for such ridiculous lies?
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gjlr7r1",
"gjlv4pd"
],
"text": [
"Hard to say for sure, but there are most likely a few factors. First, people tend to be trusting. It takes work to reject something that someone tells you, especially someone who seems confident and informed. Second, you have people who \"know\" the truth because they saw it. They saw Tupac getting gas the other day. Nevermind that it wasn't Tupac, they saw it so it is true. Finally, you have the excitement factor. How cool would it be if the masses were wrong about something but you knew the truth?! Even if deep down you know its probably wrong, its exciting to think what if you are right?",
"People aren't \"convinced\" of things in the way that you naturally think. We tend to think of other people as blank slates that are just waiting for someone to come along with evidence to convince them of this or that. This is not the case. People are like balls of chewing gum rolling across a carpet. They are already covered in opinions and prejudices and desires, which makes them impartial arbiters of evidence. When someone says to them \"I'm going to tell you _____, and then I'll explain why it's true\", they've already decided whether or not they would LIKE the thing to be true before we've even gotten to the evidence, which makes them bias the evidence one way or the other. So, the \"goal\" is not to convince them with evidence, at that point. You don't need to. They already want to believe you. You just need to give them permission. All they need is a defendable argument. It doesn't need to be true, or even mildly logical. It just needs to have a passing defensibility in case someone challenges them on it. It can be as simple as \"An important person heard it from another important person\". Good enough. And voila! You have an excited new believer who is that much more entrenched in their ideas about the world, and will continue on to tell other people!"
],
"score": [
6,
4
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kz8xey
|
Why is it that watching a movie or TV show with a lot of drinking/smoking/sex makes me want to drink, smoke, or have sex; but, watching someone study/exercise/meditate doesn't make me want to do that?
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gjlve2d"
],
"text": [
"It’s probably because you lowkey need that in that moment and these things are interesting to you. When I see movie with drinking, I don’t want to drink too, but if someone in the movie is drawing, I want to draw too!"
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kzbg9a
|
Why does it take a lot of time to move, let's say, 600GB of archives between two folders in Windows 10, but it's almost instantaneous to move the folder itself (with all those archives inside) to another?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gjmmrvr",
"gjmnpv9",
"gjo2r7m",
"gjnt682"
],
"text": [
"The way the file system works is that the windows explorer hierarchy is just pointers to the actual physical location on the drive. And moving stuff between different folders in the windows explorer hierarchy isnt moving the actual data. It only moves the actual data if you're trying to move it between two different drives. It's like you have a lot of junk in your garage and you created a filing cabinet with different folders with paper that that specifies where something is in the garage. You move a piece of paper from one folder in the filing cabinet to another folder. That's fast right?",
"Because of the way the file system is set up, moving a folder from one place to another just requires you to change the pointer telling it what folder that folder lives inside. If you're moving the contents, though, it has to do that but for every single file separately.",
"Only when on the same disc. The folder is simply relinked. So let's say you have Folder A and B and you move A into B, the filesystem is linking A as a subfolder of B. Nothing else is changed. If you move it to another Disc, you'll notice it'll take the same time as usuall as all the content is copied over.",
"Filesystems are like a huge set of library shelves. But the index to what book is on what shelf is stored in the librarian's card system. If you want all the books on, say, gardening, then they point you to the gardening section. But that might include a book on science about gardening. So they'll tell you where that book is too. But if you want to \"move\" a book so that it's in \"science\" instead of \"gardening\", permanently, then you don't have to move the book at all. All you need do is rewrite the index. That's quick, simple and needs no movement of large amounts of data (the book). It's only when you want the book in both gardening AND science (i.e. a copy) that you need to then copy the book - which is exhausting and time-consuming. And if you delete a book, you have to go to the shelves, find it, and remove it and maybe rearrange the shelf (if it was holding others up, for example). That's time-consuming too. So \"move\" is almost instantaneous. Whereas \"copy and then delete\" takes LONG in comparison. It comes up all the time in computing. It's also the difference between pointers and variables, to passing by value, and passing by reference, to DMA versus memory copying, etc. If you want me to tell you where the book on gardening is, that's easy, quick and I don't need to do hardly anything. If you want me to GET you the book, or make you a copy, that takes longer, and more effort and the computer (librarian) needs to do a lot more work. There's a reason that computing uses a \"files / folders\" analogy too. You can copy a file or folder full of files if you want, but it's quicker to just give someone the file or folder (but then it means that you won't have it any more). Note that when you cross filesystem boundaries (e.g. you want to \"move\" from one device to another), this is just like moving a book between libraries. No matter what you do, it involves physical movement, effort and time. So \"move\" between two different drives is often the same as \"copy and then delete\". It's only when everything is on the same drive (in the same library) that \"move\" can be done with just an eraser and an index card."
],
"score": [
47,
13,
7,
4
],
"text_urls": [
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kzbsxn
|
How are credit card numbers generated? Can someone just type random numbers into a website and “guess” someone’s actual card, and buy something with that?
|
Mathematics
|
explainlikeimfive
|
{
"a_id": [
"gjmqaen",
"gjmtoc8",
"gjmspck"
],
"text": [
"In almost any situation, some other piece of information will be verified along with the card number, such as the cardholder's name, expiration, billing address, CVC2 code (cvc1 if the transaction is in person). The card number itself is usually not enough to complete a transaction by itself.",
"1) Card numbers are all numerical from 12-19 digits 2) Major Industry Identifier - The first digit of the credit/debit card is the Major Industry Identifier (MII). It indicates the category of the entity which issued the card. 3) Issuer Identification Number - The first six digits are the Issuer Identification Number (IIN). These denotes the institution that issued the card.",
"I know this isn't an ELI5, but [Here]( URL_0 ) is a good explanation. Basically, they are not random. The numbers are mathematically checked making it a less than 1 in ten chance that a randomly generated number (that starts with the right # based on the info at the linked page) will be a good number. Then there's the security code on the back as well, and in my experience the company charging the card wants at least a zip code, if not my full name and address."
],
"score": [
7,
5,
4
],
"text_urls": [
[],
[],
[
"https://gizmodo.com/how-credit-card-numbers-work-1493331190"
]
]
}
|
[
"url"
] |
[
"url"
] |
|
kzbt1h
|
Why are monitors 144 hz instead of a flat 140 or 150?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gjmsm4i",
"gjo57is",
"gjo6r13",
"gjp2lf5",
"gjnzaa7"
],
"text": [
"It's divisible by 24, which is commonly used for cinema. If it was 140 hz you would have some weird possibility such as 20 frames showing for 7 cycles (which wouldn't sync with cinema), or stretching some frames for more refresh cycles to make 24 frames last 140 cycles (instead of showing each frame for 6 refresh cycles). 150 would have a similar issue. 144hz was the most sensible choice because each frame can be shown for 6 refresh cycles, and it can be split in half for 3 refresh cycles for each eye if used for 3D.",
"Oh boy. 3 comments and 3 different answers. None of which are entirely accurate, but each contains some of the reasons. So long story short, 144Hz is just the perfect nexus of a lot of happy accidents. Firstly, it is divisible by 24Hz where the 120Hz standard is a factor of 30Hz. You'll generally find these two factors behind most monitor refresh rates. Sometimes you'll find oddball refresh rates, but they don't ever catch on. 24 and 30 will be the two factors you'll find as one is the traditional framerate of film and the other is the traditional framerate of television. You scale upward from there. EDIT: I just want to note that there's absolutely no other reason to use framerates divisible by 30 or 24. There's no inherent benefit from them. It's simply adhering to traditional standards. Second, 144Hz brings you under the 7ms pixel response time. 6.9ms to be a little more specific. (1000ms / 144 = 6.944...) This means you can get the full benefit of 7ms response time LCD panels. (This isn't something I'm intimately familiar with so I hope I'm explaining it properly. Just going by how it was explained to me.) Third was bandwidth limitations. I'm unable to find the original source for this at the moment so I'm going by memory. At the time that 144Hz monitors began appearing on the market the bandwidth limitations were in that same range. You couldn't really push much more information to the monitor and because of points 1 and 2, 144Hz was settled on. EDIT: Someone below put in the actual technical specs that backs me up on this: URL_0 tl;dr: The maximum refresh rate of a 1080p image at 24-bit color depth is 159Hz. 144 was picked because of the first two points because it's the nearest \"standard\" refresh rate. There's also anecdotal accounts that overclocking of displays landed on 144Hz because it is exactly 20% faster than 120Hz and was the sweet spot for overclocking. Of course there's absolutely no concrete evidence that I could find. Mainly just going by what people say worked for them.",
"Most of the answer is not really correct. Put it simple: DVI dual link max data rate is 7.92Gbps. 7.92G/1920/1080/24(bit per pixel)=159 The closest number that divisible by 24 (somewhat \"standard\" framerate) is 144",
"Better question why does my 27 inch gaming monitor at 2k 144hz cost more then the 50 inch 4k smart tv I just bought?",
"Lets do some history: it's the 90s and CRTs are everywhere. CRTs will have a noticeable flicker when using a low refresh rate. That's why they're all at least 75Hz or more. The 2000s come around and LCDs go big. LCDs are always backlit and there's no back flickering between the frames. So 60Hz was enough. Now fast forward to 2008 or so: 3D is coming back! But wait: they use shutter glasses to show one frame for one eye while they black it out for the other eye: flicker is back. And 120hz just wasn't fast enough to not see flickering (the 120 hz had to be shared across both eyes. Leading to a 60hz shutter on the glasses, which made the flickering visible again). Now comes 144hz around, 72hz for each eye and the flickering is gone. I sadly couldn't find the source, but that is what I remember reading back in 2010 or so"
],
"score": [
6206,
545,
87,
20,
18
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"text_urls": [
[],
[
"https://www.reddit.com/r/explainlikeimfive/comments/kzbt1h/eli5_why_are_monitors_144_hz_instead_of_a_flat/gjo6r13/"
],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kzc502
|
. Chromosomes DNA and Blood transfusion.
|
When I donate blood, or plasma, platelets, how does my DNA affect that of the person being transfused? Does my DNA Get replaced by theirs?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gjmu08u",
"gjn3dgk"
],
"text": [
"No. Red blood cells do not contain DNA. Plasma is fluid and proteins and platelets do not have a nucleus. Also, red blood cells are made by your long bones, so transfusion blood cannot reproduce new cells.",
"When you inject something into someone else it behaves exactly like that - something foreign injected into someone. Your blood mixes with their blood, and a little bit of you lives in them. Your cells will always be your cells, and theirs theirs. As our bodies are designed to detect and destroy things in our body that 'are not us', normally the reciever's body would destroy your donated blood. But, we have found that blood can be separated into types, and using the right type can minimise this reaction. In the same way, a donated heart will never become the receiver's heart. It will always be someone else's heart surviving in another body."
],
"score": [
16,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
kzchox
|
Why is the computer mouse called a mouse?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gjmwocs"
],
"text": [
"It was originally called X-Y position indicator for a display system. Later it was called a mouse because it looked like a mouse. URL_1 URL_0"
],
"score": [
31
],
"text_urls": [
[
"https://www.devinedesign.net/why-is-a-mouse-called-a-mouse/",
"https://time.com/3831359/computer-mouse-history/"
]
]
}
|
[
"url"
] |
[
"url"
] |
|
kzcmao
|
How are calories counted on nutrition labels? In complex foods is it just the sum of the parts?
|
Chemistry
|
explainlikeimfive
|
{
"a_id": [
"gjmzbbz",
"gjmyj4l",
"gjnl38y",
"gjoc43h"
],
"text": [
"I only worked on nutrition labels for a small company (less than 20 employees), but we had software we entered our ingredients into that generated the label. It was basically the sum of the parts.",
"Theres a branch of science that determines the nutrients in a food. The simple explanation is that a calorie heats one gram of water by 1 degree C. A food Calorie, capital C, or kcal is 1000 calories. You can use a labatory setting and burn the food to see how much it heats water to determine the calories to put on a nutrition label.",
"They used to use a system that would burn things and measure the heat(bomb calorimeter), now they measure exactly what our bodies can burn and ignore the rest. It's call the [modified atwater system]( URL_0 ) and its quite accurate for our needs. In practice theres only 3 things that comprise all food kcal anyway: Fat, protein and carbs.",
"(answer based on US law; professional food scientist) Calories are derived from Fat, Protein, and Net Carbohydrates. All of these macronutrients are summed individually for all components of the food, and then multiplied by 9 (for fat) or 4 (for protein and carbs). 9 and 4 are roughly the number of calories per gram of these nutrients. The amount of protein, fat, and carbs can be derived by two accepted methods 1) Analytical testing by testing the food itself or the individual components (and then summing) 2) referencing previous analytical data for constituent parts, typically from the USDA food database, and then summing them. Calories are, by law, rounded. Calorimetry (burning food and measuring output) has its place in aiding label creation, but on US labels, calories must be attributed to the macronutrients (fat, protein, carbs)."
],
"score": [
8,
6,
3,
3
],
"text_urls": [
[],
[],
[
"https://en.wikipedia.org/wiki/Atwater_system"
],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kzd79n
|
A new rampant UK television advert I've noticed points out that '1 in 2 of us will get cancer'... I've Googled around a little bit... So, out of a friend of mine and I for instance, one of us will get cancer?... That sounds a bit much that half of all the people in the UK will get cancer??!!
|
Mathematics
|
explainlikeimfive
|
{
"a_id": [
"gjn1s6g",
"gjn44vf",
"gjn3bft",
"gjn8ma4",
"gjn83sz"
],
"text": [
"Everyone who lives long enough will *eventually* get some form of cancer. If both of you live into your 70s, chances are pretty good that one of you is going to deal with it.",
"No that’s not how statistics work. Neither you nor your friend are *guaranteed* to get cancer. But if on average, 1 out of 2 people does, then for every however many “2 peoples” there are, that many “1 people” will get it. Half of all people, basically. But that includes *all people* and only holds true on a similarly large scale. Smaller sample sizes (like two people, or even two hundred or two thousand) will tend to deviate from the average quite a lot. The larger your sample gets, the closer your numbers should match. If you look at a million people (a million dead people, unless you can see the future,) probably very close to half of them will have had it at some point or another (assuming that figure is accurate, I haven’t fact-checked it at all, just showing how stats work.)",
"Over a lifetime, given all the types of cancer there are... yeah, 1 in 2 sounds right. Some will have childhood leukemia, others will get lung cancer in their 90’s. Breast cancer, prostate are fairly common, etc.",
"Cancer is what happens to you when nothing else gets you. Stone-age cave-man didn't really suffer much cancer, because he just didn't live long enough. Cancer is a purely by-chance mutation of a normal body cell such that it grows out of all control but the body just thinks it's part of the body. It happens by chance all the time, thousands of times a day, but often the immune system catches it, or the mutation causes the cell to die instead or the mutation is harmless. Things like radiation, carcinogens, etc. increase the risk of it happening (i.e. make it happen more often) but you can't \\*stop\\* it. Even if in a perfect bubble with a new-born baby, cancer can still happen, because it just needs the tiniest thing to cause a mutation. As such, we can't \"cure\" it - we literally have to wait for you to get it and then get rid of it, but you can't stop it happening in the first place (only lessen the chance by not exposing yourself to carcinogens). Hence, over time, if you don't die of anything else, you'll die of cancer eventually. An immortal being able to recover from all injuries and illnesses will get cancer eventually. Their own body has everything it needs to give them cancer, and it's just pure chance whether it forms, whether it gets lucky and is able to grow, whether the immune system catches on or not, whether it forms in a critical part of the body, etc. etc. So, yes, cancer will eventually affect us all - and that's an indication of how good healthcare is now, believe it or not... cancer's always been around but you're far more likely to get it nowadays because all the other stuff won't kill you first. Cancer is body-death. It's cell-expiration. It's life-lottery. Now consider statistics that you can't grasp the scale of - that 1/3rd of women have been raped, 1% of us are intersex (i.e. neither scientifically male nor female), 39% of people are overweight or obese. Half of us getting cancer is pretty much a given - it's literally in all our bodies in potentia, mutations that could be cancerous probably happens every single day in every person on the planet, but our systems are good at weeding them out and the rest is just chance over whether the mutation is in the \"don't stop growing\" part of a cell. Even if we lived 200 years on average, I bet about 80-90% of us would get still cancer in our lifetime. And it's something that you can't \"stop getting\". You can only get better at treating it when you do get it.",
"I can't speak for the UK, but in Canada I believe it's about 45% of people will get cancer at some point in their lives (the top four diagnosed are prostate, breast, lung, and colorectal cancers). Most cancers are diagnosed in people over 65. That doesn't mean that everyone will need chemotherapy or radiation. Some may just need surgery, some may choose no treatment at all. My Dad has had cancer twice, melanoma in his 40s and a kidney tumour in his 60s. Surgery removed both. You would never know he's had cancer and he kept it relatively private. Cancers aren't rare unfortunately. However, our ability to catch cancers earlier, treat them more effectively, and manage the side effects of treatment means more people survive cancer now than at any other point in history."
],
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12,
4,
4,
3
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|
[
"url"
] |
[
"url"
] |
|
kzd7oa
|
What is the scientific answer for why both joy and sadness make us cry?
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gjn3ofk"
],
"text": [
"Crying can be used to signal intense emotion, both positive and negative. Context can generally be used to tell the difference."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kzdwwb
|
Do bears/lions/tigers or whatever really have "razor sharp" claws or are they just big ass claws? Having literal razor sharp claws seems dangerous even for the animal itself.
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gjn7bvk",
"gjna3mt",
"gjndl94",
"gjo0l93",
"gjoctm2"
],
"text": [
"I reckon that house cats have sharper claws than those animals. Sharpness is a factor of thinness. Bear claws are massive. But, when any of those animals swings their arm with all of their power behind it, then yeah, the combination of speed and claw make them pretty dang sharp. Really, though, “razor sharp...” is just a colorful turn of phrase not meant to be taken literally.",
"They might not be able to shave your beard, but all cats except cheetahs retract their claws when not needed. So they're going to be pretty sharp.",
"Not sure about big cats since they have retractable claws, but bears do not. They are big and blunt since they do a lot of digging for food. However, there is enough force behind a swing that it doesn’t really make a huge difference if they’re sharp or not, they will tear through most flesh with minimal effort.",
"Big cats have some pretty sharp claws, but if you tried to use them like an xacto knife, it wouldnt work. More like a big dull pencil But if you were to stab someone with a dull pencil, you will probably still fuck their day up. Bears claws are quite dull, more like a rock that used to be pointy but was on the coast for a long time and got smoothed out. But they're attached to a fucking bear... so they will tear right through you As for it being dangerous for the animal, cats can retract them, so they're basically sheathed. And bears? Bears could have chef knives for fingers and probably be just fine. If you show up to a bear fight with a standard-issue police pistol, your chances are still *real* bad. They're tough as fuck",
"“The expression razor sharp undoubtedly refers to the fact that the keenness required of a functional straight razor is very near the limits of what the physical properties of steel permits.” A full breakdown can be read here: URL_0"
],
"score": [
25,
8,
6,
4,
3
],
"text_urls": [
[],
[],
[],
[],
[
"https://scienceofsharp.com/2014/01/25/quantifying-sharp/"
]
]
}
|
[
"url"
] |
[
"url"
] |
|
kzdyre
|
What is that “chilling sensation” from tea tree oil, bio freeze or icy hot ?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gjnc568",
"gjnc8t4"
],
"text": [
"Biofreeze and icy hot contain menthol, a chemical compound that happens to stimulate the cold-sensitive receptors in your skin and other tissues. This is actually the same reason that capsaicin, the 'spicy' compound in peppers, causes a hot sensation - it stimulates the heat-sensitive receptors. *Why* this is exactly isn't really clear. It seems kind of weird that we would have heat receptors in our cells that also randomly respond to certain compounds produced by plants. One theory is that the temperature-sensing equipment evolved first in animals, and then plants evolved the compounds as deterrents to make animals not want to eat them. But then we humans come along and we're a bunch of weirdos who decide we like the feelings these chemical deterrents cause",
"It's menthol, a local anesthetic (makes the area numb) and counterirritant (it triggers a reaction in the body). It also triggers certain receptors (sensory proteins) in the skin that are responsible for detecting heat loss or cold."
],
"score": [
27,
4
],
"text_urls": [
[],
[]
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}
|
[
"url"
] |
[
"url"
] |
|
kzdzrf
|
Why does the heart muscle not get fatigue?
|
Your heart is beating 24/7, so why does it not get tired like other mussels after they are worked for so long?
|
Biology
|
explainlikeimfive
|
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"Nobody has said it yet, so I will, even though I'm not exactly an expert. 1. Heart muscles are different from skeletal muscles. They are different in that they contain far greater amounts of mitochondria than your other types of muscle. This lets them use much more \"aerobic\" respiration than the other muscles. 2. This increased mitochondria means that your heart *needs* oxygen much more than your other muscles, which is fairly simple, because it is the heart. If that oxygen supply is stopped, your heart is very quick to become damaged. 3. Your heart muscles do get rest, during the ~60% of the time that that quadrant of the heart isn't beating.",
"Short answer: Heart muscle is made of different types of cells to all the other muscles in the body. These cells are better at generating energy than regular muscle and do not get fatigued the same way. Long answer: The body contains three types of muscle — *skeletal/striated/voluntary* muscle, which makes up the muscles you can consciously control for moving, speaking etc; *non-skeletal/smooth/involuntary* muscle, which makes up the muscles you can’t consciously control, like your stomach, intestines, irises, blood vessels etc; and *cardiac* muscle, which is only found in the heart. They all operate by using proteins called *actin* and *myosin* which “ratchet” against one another, though each type of muscle arranges these proteins differently (that’s where the “striated” and “smooth” description ultimately comes from). This “ratcheting” requires energy, in the form of *ATP* (adenosine triphosphate), which is produced by the *mitochondria* (the famous “power house of the cell”), which use glucose and oxygen to manufacture ATP. Simplifying a bit*, skeletal muscle cells have around three seconds of ATP reserves; anything longer than that requires additional oxygen and glucose for the mitochondria to switch into high gear (*aerobic respiration*), which is why strenuous physical activity increases your breathing, burns extra calories, and makes you feel warmer. Aerobic respiration, for biochemical reasons, produces 38 molecules of ATP for every 1 molecule of glucose, but is relatively slow (hence why you have a few seconds of energy reserves to bridge the gap). If the mitochondria get into *oxygen debt* (that is, there isn’t enough oxygen to keep them running at the required output), they switch to *anaerobic respiration*, which lets them produce only 2 molecules of ATP for every 1 molecule of glucose, but is much faster; you can think of this as their “emergency fuel”. Anaerobic respiration also produces *lactic acid*, which inhibits the anaerobic respiration process if it builds up faster than it can be removed; eventually a muscle is temporarily “poisoned” by lactic acid buildup and stops working properly, which we call *muscle fatigue*. This is why you can walk indefinitely, but sprinting is only possible in relatively short bursts. Cardiac muscle avoids muscle fatigue in the following ways. Firstly, it has *a lot* of mitochondria — skeletal muscle cells are around 2% to 8% mitochondria by volume, depending on the muscle, whereas cardiac muscle is around 35% mitochondria by volume. Secondly, it is optimised for “short burst” activity, so whereas your skeletal muscles can contract for minutes at a time and need extended rest afterwards, heart muscle cells will contract for very short periods (less than ~0.25 seconds) and then rest for very short periods (less than ~0.75 seconds). The heart contracts as a complex rolling wave of muscle activity starting from the atria, proceeding down the *septum* (the wall in the middle of the heart), and ending with the ventricles, rather than as a single organ-wide contraction, so at any given moment some of the cells are resting, even mid-heartbeat. Thirdly, the heart has an excellent blood (and therefore oxygen) supply — the *cardiac arteries* arise from the aorta immediately after it leaves the heart to supply the heart muscle, so it gets “first dibs”. Does this mean your heart can’t become fatigued at all? No, actually; it is possible, just very difficult. The heart is largely protected simply by being much less prone to fatigue than skeletal muscle, so it is *borderline impossible* for most people to undertake enough physical activity to fatigue their heart — your regular muscles give out much earlier. Nevertheless, it has been observed in some extreme endurance athletes — the sort of people who will run for several hundred km in one go without resting for several days, far beyond even a regular ultramarathon — that their cardiac output can drop significantly and their heart’s activity becomes much less efficient. And, of course, this is essentially what a *heart attack* is, especially in the case of a *myocardial infarction* — where oxygen supply to the heart muscle is interrupted, typically by a blockage affecting a cardiac artery that supplies the heart muscle. Source: I have an MSc in animal and human biology. ^*Okay, ^simplifying ^a ^lot. ^Look ^up ^creatine ^phosphate, ^glycolysis, ^and ^the ^TCA ^cycle ^if ^you’re ^interested ^:)",
"So, I'm not an MD, but I did take first year medicine studies. The short, it does. Your heart gets rest when your brain rests. While it shuts down certain functions, the heart rate also slows down which takes a toll off. Another major event is how the heart works. The way your heart beats while being used, it gets breaks as it pumps from one section to the next. Much like when you breathe in and out, that moment when you stop is the rest. Now a more complex but simple explanation from here is the pain and tiredness. Your body is really good at ignoring normal function fatigue. When the brain rests, the fatgue starts to go away. Your body attacks areas of inflammation and fatigue. Usually this takes 4-8 hours but changes person to person. Now when your body does fail, and the heart is tired you get a few reactions. Your heart either races until it stops, or it stops. Cardiac arrest, or a heart attack. American heart association has further info, much more detailed."
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[
"url"
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[
"url"
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kzejrq
|
why isn’t there a standard size for a baseball field?
|
Other
|
explainlikeimfive
|
{
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"Baseball is really old, from an era where they had to play wherever they could. So, instead of specifying a field size and shape, they stated parameters with enough leeway to be able to fit a baseball field in uncommon places.",
"Believe it or not, most team sports don't actually have a standard sized field. Notable exceptions are rugby-like football codes (rugby, rugby league, American football, Canadian football), which all have standardized field sizes. In addition, ice hockey and basketball have more or less standardized \"fields\", albeit that various leagues may impose a variety of different standards. Other than these few though, standard field sizes are quite unusual. But back to baseball. Despite what you might have been told, baseball is just one of a whole family of sports called bat-ball games that all kinda developed out of each other. Other sports in this family such as softball, cricket, rounders, French cricket etc all feature an unstandardized field. Baseball is no exception.",
"_Part_ of a baseball field -- the infield -- is standardized. But the entire field has only minimum size requirements because that's the tradition of the sport.",
"The original ballparks were usually build in cities and had to be shaped to occupy the land they were built on. Fenway is the best example of this, with the Green Monster being the result of not being able to use the land behind left field. In the 60's and 70's, parks got closer to standardizing. Many parks from this era have a smooth 8 foot tall fence around the entire outfield, 325 to the foul poles, and 400 ft to center. In the 90's, teams and fans realized this was pretty boring, and so teams can experiment with having inconsistent dimensions, wall heights, and corners. I believe the only rules are a minimum of 320 ft. to the poles and 400 to center, and the league can grant exemptions."
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|
[
"url"
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[
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|
kzeqkc
|
Why can't PC manufacturers use GDDR5 as system memory like PS4?
|
Technology
|
explainlikeimfive
|
{
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"text": [
"GDDR vs DDR is a matter of usage. GDDR is optimized for bandwidth, sending lots of data at once which is good for parallel processing. DDR is optimized for latency which is better for CPU tasks. The numbers are also a bit confusing because the generations don't really line up between the two. GDDR5, and 4 are based on the same tech as DDR3."
],
"score": [
15
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[]
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|
[
"url"
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[
"url"
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|
kzf26j
|
Why do my eyes start to tear up when it’s windy or cold outside?
|
Biology
|
explainlikeimfive
|
{
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"text": [
"The wind drys out your eyes. The point if tears is to protect your eyes as well as lubricate it, so when your eyes dry up, you tear up in an attempt to restore that outer layer of moisture.",
"The wind blows away the moisture on your eyes. Your tear ducts produce new moisture to counteract that. However, because tearducts only 'create' tears in the corners of your eyes, and not immediately on the entire surface of your eyes, the tears are not very efficient in replacing the moisture, because it first has to be spread out by your eyelids, but because the wind is still blowing away your tears, your tearducts have to overcompensate and basically make you 'cry'."
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3
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|
[
"url"
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[
"url"
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|
kzfe9j
|
What does it mean for something (a tax) to be 'revenue neutral'?
|
I could not find a decent explanation of the term Revenue Neutrality, but from what I gathered, it means something like this (please correct me if my understanding is flawed): revenue-neutral tax reform means that a certain tax rate may be increased and more revenue collected from this tax may be used by the government to cut other taxes and still collect the same amount of revenue as before the reform. An example with some context: revenue-neutral modification in capital gains taxes that increases rates sharply on assets held for short periods and decreases them considerably for assets held for 2 years or more.
|
Economics
|
explainlikeimfive
|
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"pretty much. basically just means the government is changing the tax structure but expects to bring in the same amount of money. basically it takes the dildo out of someones ass and puts it into someone elses",
"You are correct. Offseting a revenue decrease in one income stream with an equal increase in another stream or streams",
"This happened by me with property tax. they never did a property tax evaluation for 30 years. In that time one side of the city went up 10x in value while the other side remained the same (taking account inflation). so the city restructure the tax and my tax went down by 50% while the other side of town went up by 3x what they were paying before. in the end the city maintained the same revenue."
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3,
3
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[
"url"
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[
"url"
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kzfkej
|
why many old mathematical equations still unsolved? can't we just use computers to solve them?
|
computers and smartphones today are able to solve all mathematical equations from any textbook so why there still many unsolved mathematical problems that you will get huge prizes to solve or prove?
|
Mathematics
|
explainlikeimfive
|
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"text": [
"Because they're not mathematical equations, they're mathematical *problems*. Lets look at [Fermat's last theorem]( URL_1 ). The theorem is pretty simple: it says that for every n > 2, there are no positive integers values a,b,c,n such that a^n + b^n = c^(n) (this is opposed to n=2 where you can find infinitely many a,b,c values that satisfy this equation). A computer can't solve this problem, because you need to prove it for each and every a,b,c and n. A computer might have *disproved* this theorem by finding a counter-example (if there was one), but proving it is not something a computer can do. Eventually this theorem was proven the \"old fashioned\" way. Another example of such a problem - the [Collatz conjecture]( URL_0 ). You start with some number N, and do the following: if N is even, divide it by 2. If it is odd, multiply by 3 and add 1. Repeat. The conjecture is: no matter which number you start from, you'll eventually reach 1. A computer can't solve this problem, because it would have to test each and every possible number to start from, which is impossible since there are infinitely many numbers.",
"The unsolved problems aren’t equations where someone needs to crunch the numbers, they’re problems that look at the behavior of math where the outcome hasn’t been proven. Some are along the lines of “we’ve noticed this pattern/trait, and it holds true for every value we’ve ever checked, but we can’t prove that it’s actually true for all values or explain why the pattern occurs”.",
"In order to have a computer solve mathematical equations, you first must program the directions as to how to solve the equation. Therefore, if we do not know how to solve a given problem, we cannot program(tell) the computer to solve it.",
"These kind of maths problems tend to be more complicated than simply solving an equation, and many just can't be brute forced by a computer. For example, there is the Twin Prime Conjecture. Twin Primes are a pair of prime numbers only 2 apart - for example, 41 and 43. It is thought that there are infinitely many of these pairs, but how could you prove or disprove that using a computer? You could keep checking numbers for as long as you want, and even if you get to a point where you haven't found any new pairs for ages, that would never be proof that you won't eventually find more if you keep going. Proving something like this takes a degree of creativity to find a new insight into the problem, in some cases launching entirely new branches of mathematics. There's a lot more to it than pure computation.",
"They generally aren't unsolved they are unproved which is a different thing altogether, computers are very good at solving problems, but very bad at proving them.",
"Computers are amazing at making numerical approximations. These mathematics problems are asking for *proofs*. You want to prove that a^2 + b^2 = c^2 . A computer modeler will only demonstrate that something is true with some margin of error. Even if that error is very small, it’s not a proof.",
"The following link is an explanation of the \"N-Body Problem\", a mathematics problem thats been worked on unsuccessfully for hundreds of years. Its a great breakdown of why the problem is so challenging, which can be extrapolated to answering the larger scope of your question. URL_0",
"> computers and smartphones today are able to solve all mathematical equations from any textbook They're able to solve the basic problems of algebra, geometry, and calculus. Those problems are well understood and have been for many centuries, and there are mostly not unsolved problems in those areas. Unsolved problems tend to be in areas like dynamical systems, partial differential equations, or the like that are far less well understood.",
"Because we haven't been able to mechanize creativity and abstract thinking. The moment we do, yes sure.",
"The problems it can't solve are more of a conceptual problem and not just because it will take to long to calculate. Like not being able to divide by zero or other somewhat \"paradoxical \" problems.",
"> computers and smartphones today are able to solve all mathematical equations from any textbook By memorization, not logic. The application isn't solving an equation, it's just following rules a human told it to. It knows all the tricks you are being taught, but someone has to discover them first and then program a computer to do just that. That's all fake, it's memorizing already known answer. It's like you recalling Pythagoras' theorem, that's completely different than discovering and proving it. A computer can numerically solve things. A three body problem in Newtownian mechanic for example doesn't have a solution we know of. There is no equation to answer it, like there is with a two body problem. However, a computer can just approximate it with raw computational power. Same for calculating the digits of pi, just program an approximation and let it rip. Computers are great for numerical answers to hard problems, but they need a human to find an algorithm to approximate. This doesn't get you a solution though, just an approximation answer. You could brute for numerically solve for the lengths of the sides of a triangle, but you need to discover Pythagoras' theorem to analytically (an equation) solve it. A human can do this. A computer can't."
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"https://en.wikipedia.org/wiki/Collatz_conjecture",
"https://en.wikipedia.org/wiki/Fermat%27s_Last_Theorem"
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[],
[],
[],
[
"https://youtu.be/D89ngRr4uZg"
],
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[],
[],
[]
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|
[
"url"
] |
[
"url"
] |
kzgzas
|
how come some words use different prefixes when they’re essentially the same. For example: Existent | Nonexistent, Social | Antisocial...
|
Irrelevant - relevant Unsatisfying - satisfying And how come there are words that are completely different to its antonym Wet - dry Fresh - rotten
|
Other
|
explainlikeimfive
|
{
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],
"text": [
"Essentially =/= exactly Non is like the word doesn't, non-existent means doesn't exist Anti is like the word against, anti-social means against socialization. You can have non-social people (as in people that don't socialize at all), but anti-existent stuff doesn't make sense, as it would be against existence."
],
"score": [
3
],
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|
[
"url"
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[
"url"
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kzhehp
|
Why is temperature its own SI base unit? Isn’t temperature just average kinetic energy, or something like joules/mole?
|
Energy and amount of substance are both base units so can’t you derive temperature from them? Why is it its own base unit? EDIT: energy is not a base unit, my apologies. It can be derived from them though, so if temperature is energy/amount of substance then you can derive it from base units
|
Physics
|
explainlikeimfive
|
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"Temperature is a wholly different scale. While it can be related to the amount of energy in the unit of measure, the fact that different substances have different heat capacities means that the conversion isn’t uniform from energy density to temperature. And since temperature is the driving force of heat transfer, it’s much simpler to have that measurement be its own scale instead of deriving the value every time.",
"With that logic we could convey weight in energy values (from E=mc^2) and distance in time (like light-years). Yes, the units COULD be used to convey everything in the same basis of a minimum set of units, but it's easier to talk about things in units that make sense for the scale of the item at hand. We don't count atoms, we count moles of atoms (a large number to simplify). For temperature we sometimes use celsius, sometimes farenheit, and sometimes use kelvin, but when we want to talk about the energy something is conveying with that temperature we convert to joules. I really want to make a joke making fun of farenheit here but when talking about temperatures that make sense to a human, the farenheit scale makes a stupid sort of sense. A change of 1C ambient temperature is huge compared to 1F, and if you want to avoid decimals (for reasons like programming or discussing with small children) it's pretty good to go with farenheit.",
"*All* units could be expressed in terms of another. In fact there is a unit system that does this, and the only unit it has is \"1\". Everything is just expressed in terms of the physical constants like the speed of light, planck constant, elementary charge, etc. URL_0 The only problem is that it's *really fkin inconvenient*. Pretty much everyone measures lengths and masses on a regular basis, but not a lot of people measure joule seconds or m^3 /kg*s^2. There is no fundamental reason that the SI base units are exactly those 7 we know. They're picked for their relevance to human experience.",
"Temperature is in many situations approximate the average kinetic energy this is the [Kinetic\\_theory\\_approach]( URL_2 ). It is as mention in other posts from this approach the magnitude of a Kelvin is defined. The problem is when you go to a [Thermodynamic\\_approach]( URL_1 ) it is not the same. The definition then is the change in entropy when the heat is transferred to the system. The result is that you can have a [negative\\_temperature]( URL_0 ) in Kelvin if you have a limited number of energy states So for example a laser has a negative temperature. A negative temperature is higher than any positive temperature The temperature scale it+0 K, … , +300 K, … , +∞ K, −∞ K, … , −300 K, … , −0 K. So temperature in thermodynamics is not exactly what you are used to. So you need another unit for temperature the energy per particle because that is not the definition in thermodynamics."
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"https://en.wikipedia.org/wiki/Negative_temperature",
"https://en.wikipedia.org/wiki/Temperature#Thermodynamic_approach",
"https://en.wikipedia.org/wiki/Temperature#Kinetic_theory_approach"
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[
"url"
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[
"url"
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kzhu87
|
How does a breathalyzer work? If it's measuring the alcohol in your blood, how does the air in your lungs indicate that?
|
Biology
|
explainlikeimfive
|
{
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"gjnwdh1"
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"text": [
"Your lungs are where your blood and air get almost close enough to touch, across the membranes in the lungs. While oxygen and carbon dioxide are the main substances transferring, alcohol too will “evaporate” from your blood and enter the air, which you exhale"
],
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5
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[
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[
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