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kvkgr5
|
What is a recession and a depression? What are the differences between the two?
|
Economics
|
explainlikeimfive
|
{
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"giywujr"
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"text": [
"All depressions are recessions, not all recessions are depressions. A recession is an economic term for 2 consecutive quarters of negative GDP growth. A depression is basically a recession that lasts a long time. A short hand might be that a recession lasts months, a depression lasts years."
],
"score": [
7
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"text_urls": [
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[
"url"
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[
"url"
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|
kvkgr9
|
How can allot of subtitles be so wrong? Is it that uncommon for people to watch TV with the subtitles on? Is there something in the process that makes it impossible to improve?
|
Technology
|
explainlikeimfive
|
{
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"text": [
"Live subtitles are often done by people transcribing thigns live which means they don't thave much chance to go back and gix their mistakes if they make them, like if you're typing ans you take away your backspace key andalso you have to type really fast along with stuff that isn't pausing to let you catch up, like how I typed all that. Subtitles on scripted media, like a sitcom, will often just be directly copied from the script, even though maybe a few lines got changed on set, and these changes often don't get communicated back down the line. And then there's the issue of the voiceover translators not working with the subtitle translators that other people have mentioned here, which means they might choose to translate the same media very differently.",
"A lot of times they can be computer generated, others it could be a language barrier. A person may not be aware of spelling of certain things /, words and names, and with live tv, you have to talk at the same place as the conversations, which requires the ability to multitask, listen and type. Mistakes can happen. It also depends on the speaker's accent. It's harder to put subtitles to a mumbler or someone who slurs their words, Also dialect gets in the way. A person from the north east of america would pronounce \"pecan pralines\" as peek-yan pray-lean while a southerner would say \"peh-cawn praw-len\"",
"Can't speak for bad subtitles in the original language, but when content gets translated, it's very common for the subs and the dub to not match almost at all because they're done separately. For example, in the Spongebob movie, Spongebob tells Squidward \"Better luck next time, buddy!\" when he (thinks) he gets the promotion to manager. In the French dub, they chose to translate it as \"Next time it'll be you, don't be disappointed!\", but in the French subs, the translation team went for the more literal \"It'll be for the next time, my buddy!\". Neither team had any contact with either other, but when you watch the French dub with the French subs, you'll think the subbing team is full of morons."
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kvl3hw
|
Why does it hurt when you step into a warm shower after being very cold?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"giyz82d"
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"text": [
"Your nerves have just adjusted to the cold. All of a sudden theyre introduced to warmth. Normally, the water would just feel warm, but since your nerves have now adjusted for colder temperatures, by comparison the warm water now “feels” hot. The same thing works backwards, go from a really hot shower to just warm water and the warm water will feel cold. Humans sense change by matter of comparison."
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"score": [
3
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[
"url"
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[
"url"
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kvlv35
|
How bad is it actually for me to have my laptop on my lap without an EMF blocking mat?
|
Technology
|
explainlikeimfive
|
{
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"text": [
"It is not. You’ll suffer more “damage” from your laptop getting hot running Cyberpunk 2077 than EMF baking your balls/ovaries. The EMF scare is to just sell you EMF blocking lap desks.",
"Literally not bad at all. You forget, we're being bathed in EMF at *all times*. Wi-Fi, cell signals, Bluetooth, AM/FM radio, background radiation from radioactive isotopes of carbon and potassium and a host of other things, UV from the sun, all kinds of stuff. If the EMF from a laptop could hurt you, you'd already have died long ago from the EMF coming from your Wi-Fi router. The only radiation you need to worry about is UV (which can damage your skin cells and lead to skin cancer and other ailments) and potentially alpha, beta, and gamma ionizing radiation, though if those are on your list at all, you likely have far more pressing concerns.",
"In short, like everyone else here has said, it isn’t bad for you. Now the long part to explain why. In hopefully simple terms. To be damaging, electromagnetic radiation must be ionizing or high enough energy. Energy in EMF is directly correlated to frequency. So higher frequency = more energy/ lower frequency = less energy. So the question at what frequency does EMF become harmful? The answer is much higher than you probably think. Picture yourself on the beach. The emf your laptop produces and receives is you throwing a pebble into the ocean. The waves from your pebble quickly disappear in the chaos. No where near close to hurting you. UV rays (also a form of EMF) that will sunburn you if you are out too long are akin to a tsunami at this scale. The difference in energy between a ripple and a tsunami is the same as human emf to UV light. If your laptops emf could harm you, turning on a lightbulb or walking outside would kill you instantly. Seeing that it probably doesn’t, I think you are fine without the emf blocking pad. (To those who might comment to say that my comparison is too small by an order of magnitude here or there, note I didn’t say how large the tsunami was :) )",
"I'd be more concerned what happens when the batteries catch fire. I'm old enough to remember those exploding laptops. I'll never rest one on my lap."
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[
"url"
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[
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|
kvlyrf
|
How come everything funny seems more funny at night?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"giz4coa"
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"text": [
"Your body is fighting sleep, so you have higher levels of endorphins and other chemicals, so pretty much you’re “high” in a sense."
],
"score": [
8
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"url"
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[
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|
kvlyro
|
if a helicopter is hovering does it mean its acceleration is 9.8m/s^2
|
Physics
|
explainlikeimfive
|
{
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"text": [
"If it's hovering, then it's rotors would be exerting a force equal (magnitude) and opposite (direction) of gravity, and it's acceleration would be zero. If it's acceleration were 9.8m/s² down, it would be in freefall (assuming no wind resistance or other outside forces). If it's acceleration were 9.8m/s² up, it'd be going straight up *very* quickly accelerating.",
"No. The net force on the helicopter is zero, lift = weight and acceleration is 0. Gravity is pulling down on the helicopter with force equal to the helicopter's mass accelerating at 9.8 m/s\\^2. The rotor(s) are producing an equal upward force to exactly balance gravity."
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8
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[
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kvnc6m
|
Why do we hold our hand/hands in front of our mouth when something bad happens?
|
Other
|
explainlikeimfive
|
{
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"text": [
"3 reasons come to mind: 1. Social ingraining. We do it because our parents did it. If you notice, adults cover their mouths when shocked but little kids don't. 2. (related to 1) it's considered impolite for your mouth to be open and uncovered for any reason. That's why you cover your mouth when you yawn (or, should). That's why you close our mouth when you chew (or, should). 3. To mentally 'protect' yourself from the thing that just happened. This would be the same mechanism that causes people to cover their eyes from something they've already seen or 'sadness cuddle' with someone they view as protective of them."
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5
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[
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|
kvnk1t
|
Why did cordless home phones from the 90's need a two-foot antenna in the house and now we can walk into the middle of nowhere and talk with no antenna?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gizdw67",
"gizcx0f"
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"text": [
"It has to do with the radio frequency the phones were using. Your cordless phone from the 90s operates on a frequency of around 46 to 49mhz. To calculate the length of antenna needed we use a formula, length in feet = 468 / frequency in mhz. This gives you an answer of 9.55 feet, but that is for a dipole antenna, think of it as a double sided antenna. So we divide that number in half for a single sided antenna and you get 4.78 feet. So now your 4G cell phone is using a frequency of 1900mhz, so if we plug that in you see that we need an antenna that is 1.5 inches. Now the antenna is small enough that it fits inside your phone. The antenna is built in to the circuit board of your phone.",
"They still have a antenna, it just housed inside in the phone. In the old days the radio frequency was low and as a result larger antennas were required , now days higher frequencys are used and the antenna can be very small, also there's been a technology change on antenna design"
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4
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kvnohm
|
Why is there different percentages of milk?
|
I know that they all come from whatever animal or whatever, but I never understood the percentages and stuff. Does it have any health benefits? (I haven’t had milk since I was 4, so I don’t really know.)
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gizd51x"
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"text": [
"The % you see on the box/carton refers to the concentration of fat in the milk. Skim milk is lowest % and full cream is highest. Healthwise there are pros and cons to consuming either substance (to be fair, milk in general is not very good for humans anyway) but which one you'd want to drink would depend on the individuals diet, exercise habits etc."
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"score": [
3
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[
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[
"url"
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kvo2ld
|
How does spice tolerance work?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gizfsqk"
],
"text": [
"A molecule called Capsaicin is one of the “spicy” molecules. When you eat a ton of spicy food, it can change the way you receive the “spicy” molecule. Over time, the pain lessens because the capsaicin (and others) eat away at the sensors for pain in your mouth! This way, you can build up a tolerance by adding a bit of spice gradually to what you eat!"
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5
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[
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kvo6s1
|
if you have an iron bar 11,000 miles long and push one end, the other end won’t move for an hour. What happens with the length lost before the other end moves to go back to its normal length?
|
Physics
|
explainlikeimfive
|
{
"a_id": [
"gizfryz"
],
"text": [
"Even iron will compress under pressure. This is how a spring works. So if you push one end of an iron bar it will be compressed to a shorter length until the pressure wave hits the other end."
],
"score": [
11
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"url"
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[
"url"
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kvoimt
|
Kevlar body armor
|
Technology
|
explainlikeimfive
|
{
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"gizi584",
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],
"text": [
"There are multiple issues the biggest one is called \"back face deformation\" basically it's a measure of how much energy is transferred to the body after a bullet strike. In the case of kevlar there is a lot of back face deformation because the projectile is captured but much of the energy is transferred to the wearer as the back of the vesy bows inwards. Anything bigger than a .22 caliber has a real possibility of cracking ribs when it strikes a vest. That kind of force on a skull can kill someone just as easily as the unimpeded bullet can. But believe it or not, most armor helmets are kevlar. They're just treated with a resin (kind of like fiberglass) that makes them solid. A.solid helmet will have minimal deformation as it transfers the energy through the whole helmet. Unfortunately it's very heavy and wearing kevlar helmets for extended period will put a lot of strain on the wearers neck. Any clear face shields you see are usually not bullet resistant. They're merely there to keep debris out of the eyes. Actual bullet proof visors weigh a lot and would add even more strain.",
"Headgear in movies is problematic because it obscures the actors face. What is the point of hireing good actors if audience is still going to have a hard time recognizing their facial expressions? But even in the real world kevlar is not the only form of body protection. It is a good option when you want something flexible and strong but a bullet proof vest usually consists of other layers of protection such as hardened steel plates or ceramics. The kevlar itself is usually not considered bullet proof. But this is why for example a helmet which does not need to be flexible does not contain kevlar but instead is made up of hardened steel or ceramic composites alone. As for face proteciton this is quite common in both police and military gear but as you say there is an issue of covering the eyes, but also the ears. Firstly the helmet is designed to cover the upper half of the face down to the brows. And soldiers are trained to never expose more of their body then possible. So when facing a trained soldier the only exposed part of the body you will see is usually the eyes and hands. There is also equipment to protect the lower half of the face, either as a collar on your vest or hanging from your helmet. However this often reduces the soldiers effectiveness. Firstly it often obscures vision but most importantly it makes it harder to put the face on the rifle to create the steady connection between the eyes and the optics required for accurate shooting. And most incomming fire which would hit the lower part of a soldiers face will not be at an angle that would penetrate the brain anyway. But you do occationally see drivers and heavy machine gunners with visirs or other protective gear on their lower face. Police on the other hand are more concerned with less then lethal projectiles. So their riot gear tends to be more focused on stopping lower energy projectiles then bullets and shrapnel. This means they can use a lot of plexiglass which have the advantage of being seethrough. They are also less concerned with having to shoulder a rifle. So police riot gear usually includes both a shield and a visir which both help protecte their face."
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4
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"url"
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[
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kvoiys
|
How do kids think things that are beyond their vocabulary?
|
Like how does someone who’s too young to know the word “unconscious” think Mufasa is unconscious when Simba finds him dead in The Lion King?
|
Other
|
explainlikeimfive
|
{
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"text": [
"Early brains don't think in terms of language. They think in abstract concepts. As we get older and learn words, we begin to associate words with those concepts. For example, say you got taken to a farm as an infant, you might remember seeing the big black and white animal that goes \"Moo!\" Just because you don't remember the word \"cow,\" doesn't mean you can't think of the animal. Or maybe you remember the thing that looked a bit like a bald sheep. You don't need to remember the name \"goat\" to think about the animal. In fact, sometimes we still think in concepts rather than words. Some people don't have an internal monologue. I do, so I can't say exactly what that's like, but I imagine it's more conceptual. This is also the reason why talking to yourself can be useful. Inside your brain, your thoughts don't need to be fully formed. But when you say them out loud, you need to actually shape them and focus them, which can help with problem solving. That being said, language definitely shapes the way we think. For example, there are language where 'left' and 'right' don't exist. Directions are always referred to as compass directions, and the people always know what way they're facing. Or, most westerners tend to think of time as flowing from left to right. But in some places where they write from right to left, the think of time flowing right to left.",
"Because brains can understand concepts without knowing the word for them. Animals can understand death and sleep without knowing the word for either. Vocabulary is in itself a concept of the mind. Our brains 'understand' things by categorizing and cataloguing them according to what is similar or dissimilar, and putting a name to it is only one way our minds do that. Let's compare death and sleep. A person or animal or alien or bodiless consciousness or whatever entity can understand sleep from understanding death and understanding that sleep is like death but is not death. It can understand death from understanding life and understanding that death is not life. It can understand life from understanding that person is life (they move, they breathe, they react, etc.), animal is life, but table is not life and rock is not life. If an animal or person becomes 'not life,' the concept of death is born. If the person or animal becomes 'life but also death' or, alternatively, 'not life but also not death,' the concept of sleep is born. As the brain makes more observances and more comparisons, the concept deepens and becomes more refined so that we understand 'unconscious' differently than 'asleep.' Putting a name on something is not necessary for the brain to observe it, categorize it, and compare it to other things."
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3
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kvoltq
|
How did people determine that the elements in the periodic table were, in fact, elements and not compounds?
|
It is the elements that determine the periodic table and not the other way round, but I thought this way of making the question was more direct and easy to understand, despite the possible misinterpretation.
|
Chemistry
|
explainlikeimfive
|
{
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"text": [
"It's all a matter of testing different chemical reactions, and carefully measuring the masses of the substances input vs. the substances output. Suppose you have a tank full of oxygen and a tank full of hydrogen. You've measured the masses of these two samples, and then you combine them in a combustion reaction to produce H2O. By taking a few tries, you fine-tune this reaction so that it completely uses up the gases, with no leftover hydrogen and no leftover oxygen. You also capture the H2O and measure its mass. Now, if the mass of the water equals the combined mass of the input gases, then you know you've accounted for all the matter in this reaction. In this case, you might have found that in order to produce 90 grams of water, you had to combine 80g of oxygen and 10g of hydrogen. And now you have a math puzzle, based on the relative masses of oxygen and hydrogen you used. The ratio is 8 to 1. An oxygen atom has 16 nucleons and a hydrogen atom has 1, so an oxygen atom is 16 times more massive. And to make a water molecule it takes 2 hydrogens and 1 oxygen. That means that every water molecule contains 2 mass units' worth of hydrogen and 16 of oxygen. Or reducing the fraction, it's 1 to 8. That's the ratio we were looking for! Of course, just knowing that one ratio, 1:8, for producing water, doesn't give you all the info you need to work out oxygen and hydrogen's place in the periodic table. But as you find more and more ways to combine different reactants with each other, and measure the ratios for all of them, it starts to be possible to make deductions.",
"Irreducible components was the term! The idea that by no means can you extract any other component with differing properties than what you started with. You cannot extract anything from oxygen gas because all you have is the same thing. But from carbon dioxide you can extract carbon and oxygen. From a gas that extinguishes fire; you get a black powdery solid, and a gas that enhances fire. So not irreducible; therefore oxygen is an element while carbon dioxide is not. They would have known them by different names, but it was this long drawn out process to figure it out. Now we just use a mass spectrometer instead"
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kvp7rx
|
Why some places on Earth are deserts or have a hot desert climate, despite having nearby large body/s of water?
|
Take the Sahara Desert for example, it has 2 large bodies of water, which is the Mediterranean Sea on the north and the Atlantic Ocean to the west. Despite the abundance of moisture and large amounts of water adjacent to its location, it puzzles me. Does it have to do with the air or ocean currents, or perhaps something else? edit:atlantic not pacific lol
|
Earth Science
|
explainlikeimfive
|
{
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"text": [
"In large parts, this is because the air in the Sahara usually does not come from any adjacent place. It comes from above. The areas around the equator get the most energy from the sun and are therefore the hottest places on Earth. (Yes, the Amazon is quite a bit hotter than the Sahara, once you account for night temperatures). Hot air rises. Higher elevation means lower air pressure. So, while the air rises, its pressure falls, and this in turn means that its temperature also falls. Think about how, when a diesel engine compresses the air-fuel-mixture, this heats the fuel up to the point that it ignits by itself. Air rising in the atmosphere and therefore getting colder is the same physical effect, just in reverse. Which leads to the next effect: Cold air can not holf as much humidity as hot air. This means that while the air cools, the humidity changes into water droplets, which fall down as rain. As a lot of rain. Actually, there is so much rain that many of the areas around the equator are known as \"rainforests\". So now there is a lot of dry air in the upper atmosphere. This air has to come down again at some other place, and this other place happens to be around the 30°N and 30°S latutudes. Now there are of course also other factors to consider, like mountain ranges, but this is the reason why most of the dry areas in the world are located around those latitudes - the Sahara, Saudi-Arabia, Namibia, Australia, Patagonia, Northern Mexico/Texas/Nevada - are located around those latotudes, and almost none around the equator."
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kvpbdg
|
WhatsApp, Signal, Telegram. What's the difference between WhatsApp and the others, is it really worth changing?
|
Technology
|
explainlikeimfive
|
{
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"text": [
"Messages sent by WhatsApp and Signal are both encrypted by default, while with Telegram not always. WhatsApp is owned by Facebook and they collect all sorts of data that they can, like location and contacts. They might also read your messages, we cannot be sure. That's because WhatsApp is closed source, while Signal is open source. Every application is built from a source code. That's like a recipe that tells what exactly the given app should do and how it should look. With Signal people like programmers and security experts can check this recipe and make sure that it indeed does what it promises to do and it doesn't have any security problems. They can also check exactly what kind of data Signal collects (as far as I know, they don't collect anything). While with WhatsApp you have to trust Facebook, and given the recent problems that they had with data leaks, people are reluctant to do so. This is purely anecdotal but some people allegedly experienced ads being shown to them about topics that they only mentioned in WhatsApp conversations. Edit: I should have specified that by encryption I meant full end to end encryption",
"If you build a chat service, you will face a tradeoff of privacy and ease of use: If you want to make things secret, and not trust people with your data, then they can't do helpful things with it. On the other hand, the more stuff you put on their servers, and put them in charge of organising, the less problem you have moving your account from phone to phone, or other stuff, but in return you're also giving them the keys to your data. WhatsApp gives apparently private messaging, but they keep track of contact details and locations, and have now said they will be using those to make as much money as possible. They also allow you to move your info from phone to phone, but this means that basically they can get into your data. Also, the system is secret so you can't tell for sure how it works. Telegram is actually slightly less secure than even WhatsApp, in terms of what they tell you they can look at, as it can watch your messages as you send them by default, but they're a smaller company worried about web censorship in russia, so they're more trusted than facebook. Also, more like facebook or twitter, they have loads of semi-public channels that people can use to be public figures within their system, and so they give more features than whatsapp while being less secure, but also have a certain amount of underdog appeal. Signal is from the non-profit software group that makes the code for the encryption for WhatsApp, and they have their own messenger that does all the same basic functions, without the things that risk your privacy. Unfortunately, that means that every random voice message and shared meme goes into a massive file on your phone, and a massive backup that you have to remember to move yourself if you want to get the same info on another phone. And then you have to keep track of your password, security info etc. or you can just use it. Basically because you aren't letting a big company manage your data, you don't get access to all the possible features, but you also just get to talk to your friends without adverts or people listening in.",
"I wrote this for a different thread but will paste it here too. The difference between WhatsApp and Signal/Telegram is as people have pointed out that WhatsApp is a closed-source app run by Facebook. It might be end to end encrypted but it’s collecting and sharing so much other data with Facebook that you really just have to trust Facebook, and because it’s closed source you also have to trust Facebook that it’s really doing what it claims to be. Both Signal and Telegram are run by independent organizations and both are open source meaning private developers and security researchers can audit them and verify what they’re doing. So now what’s the difference between Signal and Telegram? Here are the notable differences security-wise: 1. Most importantly: Signal uses the Signal protocol, which contains very well studied and documented algorithms. By contrast **Telegram uses the proprietary MTProto algorithm.** It might be okay, but it certainly isn't anywhere near as well studied or time-tested as Signal's protocol. Therefore, if you care about the strength of the encryption, Signal's encryption is far superior. 2. The Signal Foundation is a nonprofit with no plans to add advertisements whatsoever. **Telegram is not a nonprofit** and while it currently has no ads, **it has plans to introduce paid advertisements**. 3. Signal is entirely end-to-end encrypted. Including group chats, video calls, etc., even stickers and reactions. All of it. By contrast: **In Telegram, only \"secret chats\" between 2 people and calls are encrypted -- importantly, \"cloud\" (non-secret) chats and all group chats are NOT encrypted.** 4. Signal is easier to use: because everything in Signal is end to end encrypted by default, you don't have to worry about making a mistake. **In Telegram you have to specifically remember to select \"secret chat\" if you want a true end-to-end encrypted message (otherwise it is no better than using WhatsApp)** and from what I remember a **Telegram secret chat is lacking feature parity with \"cloud chats\"**, unlike Signal whose encrypted chats are feature-complete. (on a side note, Telegram also does this thing of claiming its group chats etc are \"encrypted\" in that they're \"transport encrypted\", which is sort of playing on people not to know the difference. This is not sufficient, because it means Telegram themselves can still read the messages. You specifically want \"end-to-end encryption\" meaning even Telegram/Signal cannot read the messages.) So Telegram is certainly *better than* WhatsApp, but if you care about security and you are putting in the effort anyways to switch from WhatsApp to another chat service because of security concerns, you might as well go and pick the one with the strongest security, which at the moment is going to be Signal.",
"Me and my girlfriend have tried all three and we prefer Telegram. It has the best customization and features like tons of stickers/animations, a nice built in gif search, good link previews, spotify album cover preview, etc along with all the basic features the other ones have like encryption. The desktop app is also good for it, much better than Signals.",
"Here's a handy chart for some of these: [ URL_0 ]( URL_0 )",
"I've been booing WhatsApp since forever because I've always had problems with file sharing. For example, if the person sent you an image, it'll compress it, and if you didn't download it before the sender deletes it from his phone, you'll never get it. Telegram is a haven for file sharing. It does none of that.",
"The way I think of WhatsApp (and why I'm switching to signal) is they paid $19bn for it and you don't pay that kind of money to provide a free service to people, they're going to monetize the shit out of people's data. At the end of the day it falls on the user whether they consider their personal lives for sale, I for one do not."
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kvq8cb
|
How do gift card companies make money from discounted cards?
|
Economics
|
explainlikeimfive
|
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"If I buy a $100 gift card for $85, the company is getting $85 right now with the expectation that they'll have to give me $100 worth of whatever they sell at some undefined point down the road. However, not all gift cards get used. Have you ever received a gift card to somewhere you have no intention of going? Or found a gift card you received years ago on a shelf? The company got that money but never had to give anything to anyone in exchange for it. Over time a company can track how much money in gift cards never gets spent by looking at how many gift cards they sell vs how much stuff is bought with gift cards. Say they determine that 17% of gift cards sold are never used. Well, if they sell their gift cards at a 15% discount, they're still making a 2% profit. So the answer is that they know not all gift cards are going to be used, and they've calculated that by selling them at a 15% discount they'll still turn a profit."
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|
kvqgrt
|
Why are drinks fizzier when they're warm?
|
Chemistry
|
explainlikeimfive
|
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"Easy answer: When liquids are cold they can hold more gas. Extra details: In summer when rivers are warmest the water holds the least air, this can go down to 0% and frequently the fish and insects die off. In winter the water can get fully saturated at 100%. The principal of CO2 & O2 in a liquid would be the same."
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kvqlap
|
How are colourblind people able to recognize the colours when they put on the special glasses, they have never seen those colours, right?
|
Biology
|
explainlikeimfive
|
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"Others have already explained this very well. I want to point out that they are not able to recognize the colors. They can now distinguish between colors that they were unable to before. They do have to learn what they are, however. My friend got these glasses, and there was a beautiful sunset as we were driving home from an amusement park. She kept commenting on the colors, and calling them by the wrong names. She also is a retro gamer, and there was a game where she said, \"It's so much easier to play this now that I can see the bullets.\"",
"**Background** To humans, all colors are merely a combination of red (R), green (G) and blue (B). We have cells in our eyes (called cones) that compare intensities of RGB. Why RGB? The colors R,G, and B are spaced distinctly far apart on the color spectrum. And the more distinct and farther apart the cones are on the color spectrum, the wider range of colors we can see, and the more precisely we can tell them apart. **Explanation** These glasses only work for a **specific kind of colorblindness** where the green cones mutate to become more sensitive to the neighborhood of red, orange and yellow light and less sensitive to green. So now when red light comes in, the brain still gets an signal from the green cone, which is wrong. Also, when green light comes in, the green cones, which the brain usually expects to turn on, don't. This overlap of sensitivity between mutated green cones and red makes it hard to tell colors between red and green apart. These glasses help by blocking wavelengths of light between red and green, thus exaggerating the difference such that the mutated green cones can function a bit more like normal green cones. With this comparison ability somewhat restored, the \"color-blind\" can better discriminate in that otherwise problematic area of red through green.",
"From someone who has protanomalous colorblindness, your assumption is correct. We've never seen the colors before and can't reasonably talk about what they are. When I put my enchroma glasses on I'm seeing literally a different world than I normally do. It's the reason that you see a lot of emotional videos where people start crying. It's overwhelming to see the \"real\" world that we miss out on every day, how vivid and beautiful it is. Having protanomaly means I've never seen the color purple with my own rods and cones in the natural world. My eyes cannot physically process that wavelength. The glasses bend the light coming in to give my brain an imitated sense of seeing purple and the proper shades of loads of other colors as well. It really is a thing of beauty.",
"In addition to what's been said, most of those 'reveal' videos are fake. The glasses kit itself will tell you about the importance of conditioning your eyes by wearing the glasses casually for a few hours a day, for a few weeks. I've known half a dozen people that tried them; they only worked for two of them, and neither of those people had a \"Put it on and start crying\" moment.",
"If you just put the colours on paper and asked them to put on the glasses in a white room and list what those colours are, such person couldn't really tell the colours for sure. It's more of a: I know the grass is green, I'm looking at the grass, this must be what green really looks like.",
"Pretty sure a lot of those videos where the person sees color for the first time and starts crying were pure marketing. My gf bought those glasses for her brother. There was no “aha” moment. In fact, the instructions say basically to keep trying them for a while and they should start working over time. They were over $300 and they got returned.",
"Seeing colors is a bit complicated... an object isn’t red or green or blue. It’s made of material that reflects and absorbs different wavelengths (between about 380-650nm). Now our eyes see those wavelengths by basically catching them in 3 different buckets Red, Green, and Blue. Now the only thing is the buckets aren’t side by side, it isn’t that all the light at 499nm falls into the blue bucket and all the light at 500nm falls into the green bucket. They over lap a bit so droplets inbetween fall a little into both (that’s how we can feel a teal that is somewhere between green and blue). The problem is for color blind people their buckets are a little screwed up and they overlap way too much to the point where it’s hard to differentiate between the two. What the glasses do is they actually block the wavelengths where the overlap is the strongest so you get only the light that is coming at the edges of the two buckets. It’s not perfect but it helps tell things apart.",
"My fiancée's family bought me the outdoor glasses. It was our first Christmas together and I bawled my eyes out in front of her family and our kids. I put them on outside and it took about 15 minutes for my eyes to not see everything as one shade of light red. After this, I had to ask her what the colors were of several things including cars, walls of buildings, and natural things. Everything was so much more vibrant and I got chills looking at her eyes in the sunlight. The colors I already knew were so beautiful and bright, new colors like seeing red correctly for the first time was life changing.",
"You have color receptors in your eyes known as 'cones'. These cones are tuned to one of three different wavelengths of light (generally, red, green and blue). They react most strongly to the exact wavelength of their tuning, but they also react less strongly to color near that wavelength. Lastly, you have 'rods' which detect overall brightness. So let's say I shine a pure yellow light in your eyes. Your rods will give you a clue about how bright the light is. To determine the color, your red cones will detect the yellow light as somewhat distant (dim), your green cones will detect the yellow light as relatively close (bright) and your blue cones will detect the yellow light as somewhat distant (dim). The combination of all this information allows you to guess 'yellow' as the color of the light. However, while this system works fairly well for pure wavelengths of light, it doesn't have enough information to accurately describe an entire spectrum of light. In essence, you're just making 'best guesses' at what mixture of color you're staring at. In (most) colorblindness, the issue is that two of your cones are tuned to wavelengths that are abnormally close to one another. To understand why this causes a problem, imagine we're playing a game where you try to find me. I tell you how far away I am from New York, Chicago and Los Angeles. With that information, you should easily be able to triangulate my location in three dimensions. But what if I instead tell you how far away I am from New York, Chicago and Milwaukee? The fact that Chicago and Milwaukee are practically on top of one another means that I'm really giving you information that looks a lot more like two points of data (New York and Chicago/Milwaukee) than three points of data. It becomes much harder for you to locate me because even small errors can confuse the results. The same is true when your cones are tuned to the 'wrong' wavelengths. What color correction lens do is they block wavelengths located in between the too-close cones to reduce this confusion. As a result, your eyes receive an additional bit of information: a known dead zone. So instead of color wavelengths in that range being easily confused, you don't see them at all and instead rely on the color ranges you can easily discriminate.",
"I'm strong deutan, I mix up pretty much all colours depending on the shade of the colour and lighting of the room I can identify a lot of colours, but it's more memorising that grass is \"that shade of brown / green / red\" which happens to be green",
"Trying to be REALLY ELI5 here: First, colorblindness is not just seeing everything in black-and-white. ##WHAT IS COLOR? Our eyes have color sensors. Most people have 3 different colors sensor (Red, Green, Blue). When we look at a color, all 3 sensor are stimulated depending on the color. So, for example, we can see a lot of green, a bit blue but no red at all, and then our brain interprets that as a unique single color. ##WHAT IS COLORBLINDNESS? There are dozens of different types of colorblindness. The most usual are when one sensor overlaps the other, that is: one green-bluish and another blue-greenish. So the sensors are kind of redundant because they will always detect almost the same thing. ##HOW COLORBLIND GLASSES WORK: They filter out that overlapping intersection. So those two almost identical sensors will start to actually detect different colors.",
"Colorblind glasses do not actually make people stop being colorblind. People are colorblind because they are missing some types of sensors and you can not get these back. Instead the colored lenses in the glasses change which colors you are colorblind of. So the colors will change and it will make it easier to see the difference between a lot of colors. Especially if you have different color filters over each eye.",
"They also sometimes think the colors aren't real. My brother wore his glasses out to a public gathering in the woods, with a building for cookouts. He took off his glasses halfway through because he was convinced they weren't working. He thought that the tacky off pink building was white, and that the glasses made him think it was pink. Blew his colorblind mind when we all told him it was pink and he realized we weren't fucking with him",
"Anyone else with blue/yellow colorblindness fucking hate teal & maroon? Cause I hate teal and maroon. Also I’m curious to know how many women here are CB? I am a colorblind left handed woman and statistically should have a penis somewhere around here. maybe I do and it’s maroon.",
"I'm moderate to strong protanomaly colorblind. Reds appear much darker to me. Purple always looks dark blue and light green often appears yellow. If I have a very large sample I can sometimes distinguish the colors but there is no chance if it is small (like a speck of blood looks black, or the little LED lights that flash yellow/green/red to indicate functions on electronics). I tend to fail colorblind tests miserably. I tried the glasses and with the glasses I was able to achieve a perfect score. However, it wasn't like in the youtube videos at all. Maybe if they allowed me to look around a bit more I would have had a more interesting effect. As it was, I passed the test, took a look around the boutique and just thought \"Yeah, they're sunglasses, nothing is in true color but it somehow helped me pass the test\". I was underwhelmed and didn't consider purchasing them. Maybe I'll give it another try some day. But, to answer OP's question. I know what I can't see. I know purple is red and blue and I can see it in certain situations if the lighting is right and the sample is large enough. Its the contrast with other colors that is missing mainly.",
"Colorblind here. Sounds like most people have explained it pretty well. I just wanted to add about my experience with the Enchroma glasses. A local art museum was running a promotion with Enchroma where you got to borrow a free pair of glasses as you tour the museum. The only problem? The whole museum was dedicated to an exhibit by a black and white photographer hahaha. We ended up just going to the roof and having a beer while I looked over the city and looked at people’s clothes.",
"I think non-colorblind people think that being colorblind means you see the world in black and white. Although that may be true for some people it’s not generally the case. I’m red/green colorblind and I tell people I can see primary colors....it’s the shades of colors in-between that I can’t distinguish. I feel like I can see them, just can’t distinguish between them. And remember some of this isn’t as scientific as we are told because even non-colorblind people argue about the color things are.",
"You see, the glasses makes his eyes see those colors because they turn the colors that person sees into those colors.",
"Colourblind data scientist here! - I've built an app that is collecting data on colour vision to try and learn the circumstances that cause the most confusion and to try understand why it is still so common particularly in males. [ URL_1 ]( URL_0 ) test takes 4:25 on average, 100% anonymous. Hoping the results will lead to a more technical ELI5 answer in the future!",
"When you say recognise, do you mean like how they know which one is green and which one is red? I'm partially colorblind myself (red green deficiencies) and I can recognise the basic green and red even without the glasses. However, I am guessing (never tried it) that with those glasses, I can see a wider spectrum of green and red compared to what I could before. It depends on the case since there are many different kinds of color blindness.",
"Colorblind guy here. We kinda do recognize them, and kinda don't. I got a trial pair of The Glasses it seems everyone has tried, and while they work for some colors, they don't work for others (my specific case). The ones they work with I've learned what those colors are supposed to be. For example: Street signs in my neighborhood are green. To me, they're a very muted greenish/brown color, but with the glasses the green *pops*. Traffic lights to me are red, yellow and white (but \"learned: green\"). With the glasses: Red, Yellow and \"I can see where someone might say that's green.\" Colorblindness is really hard to explain...."
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kvqub5
|
The color of an object is determined by how it absorbs/reflects light. But why, exactly?
|
I understand that it has to do with which wavelengths the material absorbs (and turns into thermal energy?). The one(s) that it doesn't absorb, is the color we actually see. But what physical property determines, which material can absorb which wavelength?
|
Physics
|
explainlikeimfive
|
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"each element has has electrons on shells/layers, and those electrons constantly absorb energy and release it, depending on the vibration frequency and the number of electrons a atom has, the energy is released in different frequencies, some of those light. also molecules have Intramolecular bonds which vibrate in different frequencies that absorb light in those frequencies. therefore giving off a color in according to that. A very interesting topic in this regard is transition metals, you have metals like Chromium that have a whole range of colours depending on the oxidation state the metal is in, yellow, red, purple, and its non oxidized silver like color.",
"Its their electron configuration. Electrons sit on little energy shelves where they are stable. When they get hit by a photon thats the right energy to make it to their shelf (and not over or undershoot) then they jump up to their next shelf (they literally teleport there, it has to do with quantum stuff being weird). They get all excited with their new energy and jump up, but its not the same and it doesn’t last, their place is on their old shelf. So they fall back down, and when they do they let go of a bit of energy in the form of a photon. Something a slightly different photon because its changed from being held onto by the electron. If that photon happens to be in the visible range, then we see it as a color. Transition metals (that middle rectangle on the periodic table) and polymers do this the most cause they have more complex electron configurations that allow for a larger variety of levels.",
"Hopefully, I won't get this too wrong. It boils down to quantums. Light waves come in packets called photons. They aren't continuous. Within atoms, there are electrons and they also possess the property of only having certain defined levels of energy (different for each atom/molecule). The energy of a photon is determined by it's wavelength (\"color\" in other words). If the energy of the photon is insufficient to move the electron from a lower energy \"band\" to a higher energy band, the photon is not absorbed and basically passes through the atom. So only photons of certain wavelengths can be absorbed by a particular atom/molecule. The one's that match the energy level transitions of the electrons in that atom/molecule. The reverse is also true. Electrons \"prefer\" to stay at the lowest energy level possible. (very ELI5). So electrons that absorb a photon go up in energy but fairly quickly release that energy. This energy is in the form of another photon with a particular wavelength - but now it can be released in any direction. So incident light on an object has that energy \"reflected\" (this is not a true \"reflection\" but rather absorption then a release). And because those \"reflected\" photons have only certain wavelengths, it gives rise to the perception of color.",
"One of the things is electron orbits. You can think of electrons as orbiting round atoms. (It's not as simple as this, but this is one of the pictures people usually use.) They sit in different layers, and these layers need different energies. The inner layers are the lowest energy. But each layer also has a capacity. You can't just cram them all into the lowest layer. So the layers fill up from the middle outwards. Now, if a photon (a particle of light) hits an electron, it can jump up to a higher layer. But the jump it can do is to a layer that's some amount of energy higher where the photon has that same amount of energy. If the electron falls back down to a lower energy state, it will release a photon with energy equal to that difference. When we get fluorescent materials, say a neon orange t-shirt, there's something cool happening. The electrons are absorbing high energy UV light (which we can't see). This makes them jump way up to a high level. Then the electron relaxes slightly and drops down a bit. This releases a low energy infrared photon (which we also can't see). Then it relaxes again back to the base state, releasing a visible orange photon. This means the t-shirt is reflecting orange light, but is also converting invisible UV to visible orange light, meaning we see the orange getting a boost.",
"Energy level of electrons in atomic orbitals and the structure of the material as in the arrangement of atoms/molecules in the broadest sense. A piece of carbon material will have different optic properties depending on how the carbon atoms are arranged; if they are all random and have loose bonds between them as in charcoal, incoming light will basically bounce between different atoms haphazardly, which increases the chance of photons hitting electrons and imparting their energy. The more haphazard, the longer the journey of a light beam and less chance of it being reflected back; hence charcoal looking black. In case of graphite, carbon atoms are arranged in hexagonal rings, ordered in sheets. Incoming light will bounce between the atoms and will hit some, being absorbed or reflected, but because there’s big empty spaces in the hexagonal grid, it will have fewer interactions and more of it will bounce back, leaving graphite to be perceived as grayish with a metallic sheen (those directly reflected photons). A diamond has a very ordered structure where atoms are tightly bound in a lattice; there’s empty spaces between them, but they’re also packed tightly and orderly with only a few ways the light can be absorbed and many routes it will get reflected or passed through without interacting with any electrons (these are too busy ‘holding hands’ to interact with light). Hence we see diamonds as mostly transparent, and when incident photons hit the right way as very shiny."
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kvrlsz
|
How does the water of an oxbow lake stay there despite it being cut off from a supply of water? What stops it evaporating like a giant puddle?
|
Physics
|
explainlikeimfive
|
{
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"It's cut off from the river as a supply of water, not from any source of water. There can be groundwater that's coming across underground from the river. There can be runoff from the land higher than the lake that will drain there instead of into the river. Water is one of those insidiously persistent things. If there's a route to a lower spot or an area of lower pressure, the water will find it's way there...",
"Quite often they do eventually evaporate, it just takes an incredibly long time since there can be a lot of water in them. They also get replenished by things like rain and runoff, which slows the rate of eventual evaporation.",
"The earth near a river is usually soaked with groundwater. This groundwater replenishes the water evaporating from such a lake, or any pond that doesn’t have visible streams flowing in."
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kvs0uc
|
How does sound 'travel' during Zoom/online calls?
|
I am a teacher that is going to try and explain this to 4 and 5 year olds. They have been in a Hybrid learning model all school year, some children are online and some in person. I'd like to design a lesson around this, explaining how their voices 'travel' with a computer. Reddit, please help me simplify this concept for young children. I'll be discussing audio waves, and designing an art project around that. Any feedback is welcome, thanks.
|
Technology
|
explainlikeimfive
|
{
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"* Your voice makes a sound wave in your room. * The microphone in your laptop wiggles when the sound wave hits it. * The mic creates an electrical wiggle that matches the one your voice made. * The computer checks the wiggle thousands of times a second and writes down a number for how strong the wiggle is each time it checks it. * The computer sends these numbers over the internet to everyone else on your Zoom call. * Then each of their computers look at the numbers and create their own electrical wiggle. * They send it to the speakers which in turn wiggle, which makes the air wiggle. * This creates a wave in the air (just like your voice did) and when that gets to their ears, they hear your voice."
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[
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kvs5b8
|
Since open source software means no one person or company owns it; rather a community owns it, what’s preventing from someone making undesired changes? Also, how can open source software be secure if everyone has the codebase?
|
Technology
|
explainlikeimfive
|
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"An open source project is still maintained by either a project owner or a group of project owners. They have the authority to merge code that others write to add in to the project. Nothing gets in to the main branch of the project without their approval.",
"It's not like everyone has access to editing the main file(s), they can just copy it(them) and make their own one(s).",
"> open source software means no one person or company owns it […] what's preventing from someone making undesired changes? Nothing. But it does not mean those changes will be accepted by the group of people usually associated with that software. For instance, you can make undesired changes to Firefox, but it does not mean your changes will be accepted by the group of people usually associated with Firefox. So if *I* wanted to download firefox, I'd get it from them, and your changes would not affect me. OTOH if your change is good and you submit it to the people usually associated with Firefox, they could accept it and integrate your changes. > how can open source software be secure if everyone has the codebase? Everybody can see how a standard door lock works, you can inspect it yourself, or you can ask a specialist who will tell you how secure it is. Despite this, it does not make the door lock less secure; in fact it's the opposite, as you can inspect it and tell if there are vulnerabilities. Contrast with a proprietary door lock, that you cannot open and for which you cannot see the internal mechanism. You need to trust the door lock vendor that the lock is secure, and it's quite hard to prove it's not easy to break."
],
"score": [
6,
3,
3
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kvsn7l
|
How does Intel Optane work?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gj05ksd"
],
"text": [
"Intel's Optane sits between RAM and Flash in terms of speed and density. Its a lot faster than flash, but not as dense, and is slower than RAM but much denser so it serves as either relatively fast moderately sized storage or a fast cache for an SSD. Optane is built around [3D XPoint]( URL_0 ) which is basically a 3D grid of points and it stores bits by changing the resistance between two points to store a bit. Intel claims its not using memresistors and is modifying the bulk resistance but this seems to be disputed as to if what they're doing really still counts as a memresistor(a resistor with a memory that can be set). One of the most important things is that it is bit accessible so it can be written to quickly, or just edit the modified bits. Your standard SSD uses NAND flash which is only *block* accessible so it has to read the 512 KB, erase the whole block, modify the data, then write the new data to the block. This Read-Erase-Write process is slowwww, but XPoint allowing for bit-wise addressing means you can just write."
],
"score": [
8
],
"text_urls": [
[
"https://en.wikipedia.org/wiki/3D_XPoint"
]
]
}
|
[
"url"
] |
[
"url"
] |
|
kvswxx
|
Why is recycling not done at the level of the dumps themselves by professionals as opposed to individual people?
|
People are always expected to recycle themselves, but wouldn't going through the garbage be easier in the dumps themselves to sift all recyclable waste from non-recyclable waste and sending it to the appropriate places be a more efficient and reliable way of doing things? Is this being done in any country, and if not, why not?
|
Earth Science
|
explainlikeimfive
|
{
"a_id": [
"gj04wg5",
"gj04xxs"
],
"text": [
"Well, not everything that's \"recyclable\" even gets recycled when it is sorted into its own \"recyclable\" bin. So they already have to apply time and energy to sort *that* stuff out. It would become even more difficult to sort out legitimate non-recyclable trash from the recyclable stuff once it's all mixed together. Recycling isn't a very profitable business and most places that recycle just... sell their waste to other countries to deal with it.",
"It would be a massive, dangerous and near impossible task to sift through all the trash that people produce to sort through, and alot of what might be recyclable can get ruined by getting shit all over it. Having people sort through it first makes the process of secondary sorting (becasue that does get done) much easier."
],
"score": [
13,
8
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
kvt7p6
|
How is it that everything revolves around our sun but light and heat can escape it to get to us?
|
Physics
|
explainlikeimfive
|
{
"a_id": [
"gj07flt"
],
"text": [
"Things revolve around the sun because the sun has gravity and \"things\" are attracted by that gravity (for the rest of the crowd, yes that's not how general relativity works, but that's not important here). The faster things go, the less that attraction alters their path. At the right speed to be in orbit, they go in circles or ellipses. If they're not moving at all, relative to the sun, they fall in. And if they're going really fast they escape the solar system and never come back. Light is \\*really\\* fast. Far far far faster than needed to escape the sun. So the sun does pull on the light it emits, a little bit, but it's nowhere hard enough to stop it from reaching us. Things that are heavy and dense enough to stop light from escaping are black holes. Side note: heat doesn't really escape the sun as heat...it's almost light. It turns back to heat when the light runs into the earth. The sun does emit a steady stream of particles that have temperature, that's the solar wind, but compared to the amount of energy coming out as light the solar wind is insignificant as far as earth is concerned."
],
"score": [
8
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kvtfz4
|
how can geologists tell if a certain rock is from 4.1billion years ago rather than say 3.8 billion years ago?
|
Earth Science
|
explainlikeimfive
|
{
"a_id": [
"gj0agzj",
"gj0fl3x"
],
"text": [
"**Radiometric Dating:** By measuring the \"radioactive waste\" or decay products of isotopes found in the rock, we can mathematically calculate the age through analysis of how long it would take for the amount of radioactive decay products to be present. You can think of isotopes as atoms (like a carbon atom) that has a different number of neutrons found in the nucleus. This can be unstable, and over time the atom decays. Measuring the rate of decay for specific isotopes and measuring how much \"radioactive waste\" is present is how you get to dating. It is fascinatingly accurate, but then again it's all just math so maybe not that fascinating for some.",
"A variety of methods give indications. Radiometric dating covers a bunch of techniques, useful for different materials and different ages with different accuracies. There's also context - if Rock A is in the same sediment layer as Fossilized Tree B, we can use tree rings to date the layer and have a pretty good date for the layer. In the end though, almost all scientific measures have error bars on them. It might be \"4.1 billion +/- 0.4 billion\", and thus potentially contemporaneous with the 3.8 billion yo rock. Any good scientist will usually be happy to tell you the error bars and you can make your own conclusions from there. Sometimes the error bars are quite small though."
],
"score": [
10,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kvtqoc
|
How can our body "regenerate" some tissue when we get wounded but can't do it in a larger scale?
|
As an example, if you bite your tongue, as it heals, your own body generates tongue tissue. But if you cut it apart, your body os not able to create a new tongue. Sorry for my english, i'm not native
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gj0ca28",
"gj0cjrq",
"gj0q1ad"
],
"text": [
"Some organs like skin, digestive tract lining, and the blood have very active stem cells that are constantly dividing and replacing lost cells and tissue. Other cells in your body are more differentiated and \"specialized\". They do not have the ability to begin dividing for the purposes of regeneration (replacing lost cells). Specialized cells age and breakdown over time (eye sight gets worse with age). Side note: If you're interested, there is some reading you might enjoy on the anti-aging impacts of intermittent fasting on your cells.",
"Think about this in evolution terms. When our ancestors suffered major injury, they usually died, but shutting the wound as fast as possible gave the best chances of survival. People who survived accidents could still have offspring and were albe to pass their genes. On the other hand if your serious wounds would keep regenerating, this means whole process has to take more time, more energy, and needs care. So in our mind we can see, that it would be more beneficial in present times, but evolution does not see. Its just what gives you best chances of reproduction. And it turns out its not regeneration for us.",
"Imagine the body part is a house. When you're building it the plans and materials are readily available. When you're developing the contractors (cells) that your body has are very skilled workers so you have a great architect, designer, electrician, carpenter, general contractor and they all work together to build up a house using the plans that all these special cells share and work together to complete. Afterwards the plans get photocopied a bunch of times until they're not so good anymore, the skilled workers have left and you're left with the equivalent of the local handyman, there's some left over materials from the build, flooring, drywall, paint, etc... If you break a window you don't need to consult the plans to get it repaired, and the handyman can do it. Break up some flooring, grab some of the spare materials and you can do a patch job but you don't have enough left to fully redo the floor. That's also what causes scars, imagine you're repairing a hardwood floor and the handyman lays the patch in the wrong direction. It's still floor, just wrong. You can see from the leftover materials and the local handyman that most small repairs are a cinch but if I drive a bulldozer over half the house the resources you have available to rebuild (handyman and leftover materials and barely decipherable plans that give you an idea of what it's supposed to look like) are not going to be able to do much to help. One of the goals of stem cell research is figuring out how to 1. Track down the original contractors 2. Find the original plans 3. Provide the body with the necessary materials and have them delivered"
],
"score": [
9,
6,
3
],
"text_urls": [
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
kvtzuv
|
If all electric heaters are 100% efficient, what is the advantage, if any, in replacing an old heater with a new one?
|
[Edit: I was thinking mostly in terms of financial benefit, but safety and others is good too]
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gj0bmn0",
"gj0bsrl",
"gj0daff"
],
"text": [
"The new ones are safer - they'll shut off if they're overheating, they'll shut off if they detect that they've tipped over, and some of them shut off if they've been unattended for a while. Those extra features don't seem to affect the price much, and they're nice to have. Edit: Also, electric heater cords get fairly hot, because they carry a fair bit of current. It's nice to know that your cord's insulation is in good shape, which may not be the case with an older one. Edit 2: I said something about a combustion-product detector too, but that part didn't survive fact-checking.",
"Safety features have improved considerably. And although they’re both equally efficient at creating heat from electricity, newer designs may be more effective at *moving* the heat to actually warm the room.",
"100% efficient as far as the electricity that actually makes it to the heater itself. You could still save kilowatt hours with machines that move heated air more efficiently. Also environmental considerations regarding where that electricity comes from before it reaches your house. I can’t offer a good ELI5, but [this link may be helpful.]( URL_0 )"
],
"score": [
11,
5,
5
],
"text_urls": [
[],
[],
[
"https://www.energy.gov/energysaver/home-heating-systems/electric-resistance-heating"
]
]
}
|
[
"url"
] |
[
"url"
] |
kvuk2e
|
Why does ice stick to my hands when they are wet?
|
Chemistry
|
explainlikeimfive
|
{
"a_id": [
"gj0gjb8"
],
"text": [
"The ice rapidly freezes small water droplets on your skin, before your skin has a chance to warm up the ice and cause it to melt. This is also why sticking your tongue to a metal pole works, or why sometimes ice cubes in a drink will freeze together before they melt."
],
"score": [
4
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kvv91m
|
What the hell is the HOA?
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gj0jlw7",
"gj0lniq",
"gj0ka98",
"gj0k3fj",
"gj0kmby",
"gj0koum"
],
"text": [
"HOA stands for \"homeowner's association\". It's an organization of people who own houses in an area that you agree to join as a condition of purchasing a house in that area. Their ostensible goal is to maintain the value of the property in the area. No one wants to live next to a shitty neighbor, so having a shitty neighbor can drive the value of your property down. In practice, though, this goal ends up getting filtered through petty power-squabbles of whoever happens to be in charge of the organization - hence the generally negative stereotype of HOAs.",
"Very much [Google-able]( URL_0 ). Anyway... An HOA is a Home Owner's Association. The idea is that homeowners in a certain area will group together to form an organisation. People will sign up to be a part of it, and in doing so will agree to a set of rules. These rules will help to give the neighbourhood a particular feel, and stop things from looking out of place. They have an elected committee etc who agree on the rules and implement the policy. People often also pay fees to be a part of the HOA. But the advantage to the individual residents is that they can now act as a group to get work done. If they need to petition the government to get roadworks done, for example, it's easier. Or, if people need housing repairs/maintenance done (gutters replaces, pools cleaned, porches painted, etc.), they can go as a group and hopefully get a bulk discount from whoever would do the job. Going by Reddit stories, many are far from this ideal. But I have no experience as I'm in the UK.",
"Yes it is a group that can tell you what to do with your own house/garden. Not every community has an HOA. HOA stands for Home Owners Association An HOA is a community governing organization that implements rules for a community or condo building. In the US, there are many “planned” communities/neighborhoods/buildings that share amenities such as a neighborhood pool, playground, tennis courts, etc. The HOA collects dues from each home to pay for upkeep of these amenities, ensures that homes don’t fall into disrepair, and other administrative functions like managing recycling services. The HOA exists to govern the community’s rules. Each community has their own rules but often there are rules to ensure uniformity of appearance, such as you can only paint your house in certain colors",
"Very common in newer-built communities in the US. It's an association that effectively \"taxes\" homeowners via HOA dues, and uses that money for gardens, parks, community pools, etc. They're common in planned developments where one or two home developers are paid to build several hundred or even thousand homes in a brand new community. They'll add amenities like a gym, playgrounds, water parks, pools, etc., and they pay for that by charging each homeowner a monthly, quarterly, or annual fee. It's usually in the ballpark of $25-$200 a month. Some can be insanely expensive if the community is high end. The flip side, is what you're see a lot of. Those HOAs have their own rules. No oil stains on your driveway, no weeds in your yard, small pallet of acceptable color choices for painting your house, etc. The people that run the HOA can often nitpick the folks in their community and issue warnings or fines for violations of the community standards. They're notorious for having absolute jerks serve on their boards and it can really make life miserable for people. You can avoid an HOA buy purchasing an older home in an unplanned community, or building a new home on your own purchased plot of land.",
"A lot of suburbian neighbourhoods in the US especially may form Home Owners Associations - i.e. if you live there, you have to be a member. Nominally, HOAs are supposed to be benign or beneficial - i.e. instead of contracting with lawn care by yourself, all 100 homeowners can negotiate a better deal for everyone... a bit like condo ownership. Sometimes HOA communities have to negotiate/pay for utilities or garbage collection where its not provided by the city; maybe you hire security to patrol at night - so this collectivism can make sense. HOAs will often have rules that lay out certain guidelines for homes that belong - having similar looking homes that are consistent in style and aesthetic is usually good for property values. Noone likes that goth neighbour who paints their house completely black or the naturalist down the street who never mows and keeps a jungle on their front lawn and some badgers took up residence and mauled Nancy's kid on the sidewalk. But your membership in the HOA means you volunteer to be held to the rules, for the greater good of all (The greater good - _shut it!_) But more frequently HOAs get hijacked by a few busybodies who use their position maybe as the chair, or some other executive position to start bossing others around... or nitpicking how long you cut your grass, or starting to tell you what you can/should do with your houuse that goes well beyond the scope and mandate of the HOA.",
"It’s basically a ultra local government set up by a developer when they’re building a new tract of houses. In the US it’s fairly common for developers to buy a large area of land, sometimes even hundreds of acres, and then divide it up into small parcels and build a large number of houses on it. The developer doesn’t want the first house they sell to go to someone who puts up a swastika flag and dumps a half dozen rusted out cars on the lawn up on bricks, because that’s gonna make it a bitch to sell the rest of the houses. So they include bylaws about what people can and cannot do to their homes. While the developer is still selling houses they hold a majority of HOA votes so can enforce and control rules. After the houses are sold it gets turned over to the homeowners. The local governments like them, and sometimes require them, because all the roads/sewer/storm water management/etc are the responsibility of the HOA, not the county, so keeps maintenance costs down for the rest of the taxpayers. Some homeowners like them, because they protect property values and provide an effective recourse against some types of asshole neighbors, albeit at the cost of providing other types of asshole neighbors ways to make people’s lives miserable. You see a lot of horror stories - this isn’t entirely representative of HOA’s. The bad stories get a lot more traction than the boring ones. Most are uneventful places to live. Where the HOA board is taken over by assholes it’s ofte because nobody attends meetings or votes for the board, so a small group can end up running everything, though they could be voted out at any time if the residents really wanted to."
],
"score": [
9,
4,
3,
3,
3,
3
],
"text_urls": [
[],
[
"https://lmgtfy.app/?q=hoa"
],
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kvvies
|
Why do Gas Giants exist?
|
If they don't have a solid core, where do they create their gravity to hold all the gasses into a planet shape? I've never understood this.
|
Physics
|
explainlikeimfive
|
{
"a_id": [
"gj0l5lr",
"gj0yaw8",
"gj0mqdg",
"gj0q6n9",
"gj0s6t6"
],
"text": [
"Gas has mass and thus generates its own gravity. Which is enough to make gas clouds collapse into spherical planets, (or stars if there is enough gas).",
"Things don't need to be \"solid\" in order to have mass, and mass is what generates gravity. Further, the gas giants actually *do* have solid cores (sort of; it kind of depends on what you mean by \"solid\") in that their cores are really really strange forms of hydrogen.",
"They still have mass (and much more of it than for example Earth).m. Mass of liquid, gas or solid is still mass and will have gravity. Gas giants are probably the first plantes to form.",
"They are thought to have a small solid core, just that the vast majority of the planet is gas, just like the Sun when you get that much gas into a small area/volume the gravity crushes the atoms and molecules together making the core of a gas giant denser and may even transform hydrogen from a gas to a metal. URL_0",
"Funnily enough, we don't actually know if gas giants have solid cores or not! However, more planet formation theories do use some sort of rocky core (protoplanet). Once that core reaches a certain mass, it starts to accrete enough gas that the gas mass helps it accrete more gas--a process called runaway accretion. This can pump up a small core from \\~10 times the mass of Earth to Jupiter size or larger! There are also theories of direct fragmentation, where gas can collapse in on itself and form a planet directly without a core required. This pathway is more akin to stellar formation and requires very massive protoplanetary disks."
],
"score": [
14,
5,
3,
3,
3
],
"text_urls": [
[],
[],
[],
[
"https://youtu.be/b-gCfHXNIVc"
],
[]
]
}
|
[
"url"
] |
[
"url"
] |
kvvqs1
|
What is the difference between Old Style (O.S) dates and New Style (N.S) dates, and is there any easy way to distinguish the two?
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gj0p507"
],
"text": [
"There are a couple of different things that could be considered as the changes from Old to New. One of them is when the new year changes, and the other is how leap years are handled. When the Julian calendar was developed, people knew about leap years. They knew that the Earth took about 365.25 days to go round the Sun, so a year was usually 365 days, then every 4th year got a leap day (so 366). So far so good. Except this isn't quite right. When you look closer at the length of a solar year, you find that that method of leap years (every 4th year) ends up with about 3 extra leap years every 400 years. So, we switched to the Gregorian calendar. In this system, normal years have 365 days and leap years have 366. If the year isn't divisible by 4, it's normal. If it's divisible by 4, it's a leap year...unless it's divisible by 100, when it isn't...unless it's divisible by 400, when it is. So, for example, 1998 normal, 1999 normal, 2000 leap, 2001 normal. But also 1898 normal, 1899 normal, 1900 *normal* 1901 normal. However, because the Julian calendar was meant to start on a specific date, making the Gregorian calendar line up with it involved skipping a bunch of dates. If you were in Britain in 1752, September started like this: Tue 1st, Wed 2nd, Thu 14th, Fri 15th. There was no 3rd-13th. However, this adoption didn't happen at the same time all over. Britain were a bit late to the party (since the Gregorian calendar was a Roman Catholic invention). This can lead to amusing situations like, for example, William III leaving the Netherlands on 11th November 1688 and then arriving in England on 5th November. & #x200B; The other thing that could be described as the switch from Old to New is the year change. This used to happen between March 24th and 25th. So, the dates would be something like 23/3/1598, 24/3/1598, 25/3/1599. I think most places tended to shift when New Year happened at the same time that they switched from Julian to Gregorian. Scotland didn't, weirdly. & #x200B; To answer the second part of your question, can you easily spot the difference? No, not really. This is why science will sometimes use the astronomical date, where you just start counting the days from 1st Jan 1AD."
],
"score": [
7
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kvw4z7
|
How do they put magnets In iPad cases without fear of damaging the iPad?
|
SSL
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gj0poza",
"gj0qqxt"
],
"text": [
"Magnets are harmless to electronics. The only exceptions are magnetic based devices, such as: * Magnetic storage. VHS tapes, floppy disk, and hard drives. They aren't that susceptible though, it's not like a magnet anywhere near them is doom. Modern hard drives in a computer or laptop (if not already SSD) are magnetic based, but not exactly easy to wipe with a magnet vaguely near the computer. I wouldn't go rubbing rare earth magnets directly on a drive though. * CRT TVs and monitors, the big, old, heavy ones. A magent near then will temporarily distort the image and colour. Electromagnets aim a beam to make an image, so a magnet alters the beam path. A phone/tablet has none of these. It has solid state storage, and it has an LCD or LED screen. Nothing magnetic based.",
"Magnets do not damage electronics in general. Magnetic storage can have problems with magnetic filed but for example, a hard drive has a very strong magnet in it that is stronger than any that is on a tablet case. But it is irrelevant as an iPad use flash memory. Floppy disk and CRT screen can have problems with agents but that is not common technology in the last decade to too. There is two possible part of a tablet that a magnet can have an effect on. One is if it has a magnetic compass and the result is that it do not detect north correctly or if there is a hall sensor or something similar that is used to detect magnets. There are some tables that use them to detect to detect if you close the of the case over the, So you have a magnet on the lid that will be over the sensor when you put it over the screen. That is also how most laptops detect if you close the screen, a magnet in the screen and a sensor in the bottom part- So there is nothing in an iPad or any other tables that a magnet of the damage. At worst you get an incorrect compass reading. A very strong magnet could of course have an effect but we task about the magnet that a human has a problem removing from a metal surface, nothing like that is in an Ipad case."
],
"score": [
19,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
kvwgfq
|
If we know how much damage we’re doing to the environment, why are there not more laws to prevent things like non biodegradable products, and more infrastructure to assist in renewable energy sources?
|
Earth Science
|
explainlikeimfive
|
{
"a_id": [
"gj0rbuu",
"gj0sxw6"
],
"text": [
"Because companies dont want those regulations that would cost them money; so those companies lobby politicians to not make those laws",
"That’s a weirdly deep question that should be simple. Lobbying from businesses is huge but also there’s a group of people who I think genuinely don’t either care or think we make that big of an impact. Also as far as some Christians they think Jesus will come back before the earth gets too bad and possibly by rushing it along they can hurry the return of Christ."
],
"score": [
15,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kvwhul
|
- "They/he" - I am trying, but can't seem to get my head around the "they" pronoun in this pairing
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gj0s2lw",
"gj0ry7q"
],
"text": [
"It means either they/them or he/him is perfectly fine. Some people see themselves as non-gender-conforming people but don’t mind if binary pronouns are used.",
"I think it means you can use either he/him or they/them for this person. However, I’m not certain what they personally meant. I’m sure they wouldn’t mind explaining it to you. Just say “I noticed your pronouns are he/they, what does that mean?” Most people who have their pronouns in their bio are happy to educate others"
],
"score": [
4,
4
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kvwync
|
Enzymes lower the activation energy for certain reactions, but why is that different from changing the energy released or used in the reaction?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gj0v17y"
],
"text": [
"Chemical reactions don’t instantly go from start to finish, there’s a physical process that has to occur where the atoms must rearrange and move past eachother. Since atoms are shrouded in electrons that repel eachother with considerable force, it can be difficult to actually make that rearrangement happen - there’s a high energy “transition state” that occurs when the molecules have contacted but not yet fully reacted. A catalyst changes the process and/or geometry of that transition state, lowering the energy needed to reach it and speeding up the reaction. Now instead of going 10-28-7 and releasing 3 energy, you can go 10-12-7 and release 3 energy. You still release only three, but you don’t have to gather up eighteen first to initiate the process anymore."
],
"score": [
11
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kvx3cx
|
What makes sour stuff sour?
|
Chemistry
|
explainlikeimfive
|
{
"a_id": [
"gj0vgv5"
],
"text": [
"Acid. The taste buds on your tongue that trigger the sensation of sourness are activated by the presence of acid."
],
"score": [
7
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kvxzhb
|
We don’t know what dinosaurs really sounded like, so how and why is the stereotype that they roared?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gj10yn2",
"gj11930",
"gj11865",
"gj11tlp",
"gj11wyz"
],
"text": [
"It's a media portrayal thing. They're big scary predators, so we gave them roars like the big scary predators we know (like a bear or a lion or whatever). Just an artistic choice.",
"We have Spielberg to thank for much of our perception of dinosaurs, including the sounds they made. Actually, most predators don't roar when chasing after prey. It doesn't make sense to scare food away—better to stay stealthy while on the prowl.",
"Roaring is scary, and dinosaurs are scary. Many scary animals roar, so that's a second source of confirmation. There aren't many animals with similar hardware that sound differently. There is some prospect that some may have had a whistle/trumpet sort of sound capability, but they aren't the scary kind, they are more the prey kind of dinosaur.",
"Actually, there’s a scientist who has re-created what various dinosaurs would sound like based on their physiology and the sounds made by their current descendants/near relations. Mostly drum like sounds, whistles, hoots and clucks. As others have said, the roars are to make them identifiable to humans as apex predators (since those are the sounds mammal predators make).",
"There has been some work done on the size and shape of the vocal tract of dinosaurs and therefore the resonant frequencies, T. Rex in particular. The conclusion was that it was probably more like a low rumble, somewhat subsonic to our ears. The movie stereotype is just what the director or sound people thought would fit best with their portrayal."
],
"score": [
7,
7,
4,
3,
3
],
"text_urls": [
[],
[],
[],
[],
[]
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}
|
[
"url"
] |
[
"url"
] |
|
kvyjec
|
why is the history of the world/civilization studied using BC/AD?
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gj15mv4",
"gj1886e",
"gj1cb8e",
"gj15eqn",
"gj15btp",
"gj15jmc"
],
"text": [
"BC (Before Christ) and AD (anno domini - the year of our Lord) relating to Christianity/ Life of Jesus were designated to years based on the reckoning of when Jesus was born. So anything dated before Jesus' birth is BC, after birth is AD. However, more recently these are being replaced with BCE (Before Common Era) and CE (Common Era) to move away from the religious association Edit: as I understand, it was a monk in 525 AD (Dionysius Exiguus) who began counting the years after the birth of Jesus using the dates that were set down in the Easter Tables by the First Council of Nicea in 325 AD - they set out the date for when Easter was to be be celebrated. BC/AD grew in popularity under the Holy Roman Emperor Charlemagne (9th Century) where the system was used as the standard for dating acts of government throughout Europe.",
"I’m going to try to give you a more detailed answer that just “because that’s what medieval Europeans used” and tell you why they used it. Even today it’s hard to tell exactly when something happened. When they created this calendar system in the 6th century they felt they could accurately count back to the birth of Christ by tracing the papal lineage (among other methods). Beyond that it was very difficult to determine when something happened due to different dating systems. For example, the Romans would rarely use a specific year. Instead they would write “in the fourth year of the reign of X.” But the Europeans often wouldn’t know when X reigned or the order of the Roman succession. They did not have access to the historical documents that we have today recovered. So essentially they said, “we know for certain when this event happened and how many years there have been since that event. Therefore will count everything from there going forward and everything else we can figure out later.” That is what led to AD, the number of years Christ has reigned*, and BC, everything before Christ. *in their view",
"BC is before Christ, AD is anno domini (year of our lord). There were many different calendar systems over time but given the dominance and global reach of the west the Gregorian Calendar is the standard. It’s much easier to navigate and trade if everyone has a standard system, which is also why the prime meridian is in Greenwich England, because at the time the British were the rulers of the seas. Now many scholars use BCE and CE as before common era, but IMO that’s dumb because we’re still counting from Jesus we’re just pretending we’re not.",
"Because Christianity dominated/dominates the western world and almost all history was/to some extant is told from the western perspective (former colonies are telling their own histories now but the scholarly nomenclature has stuck).",
"Because it's the dating system that the biggest part of the world is most familiar with, in day-to-day stuff. It's 2021 right now, so if I were to see something that was dated 1000 BC/BCE, I could easily look at that and say \"Whoa, that was about 3000 years ago!\" If I saw something that was dated year 2760 of the Hebrew calendar, I wouldn't necessarily know it, but that's actually the same year as 1000 BC - or one year off, depending on date, but whatever. We always work best in the system that we're most used to. History has many, many dating systems, from long-lived calendars to things like \"in the 5th year of the rule of King X.\" It can be really hard to keep track of them mentally. So to make things easy, we translate the year to the system that we're most familiar with, just like how we (in English-speaking places) might study the history of Germany, or India, or wherever and translate their historical sources into English for study.",
"Because that's the system that was commonly used in Western countries. We need some point in time to start counting the years from, and it is completely arbitrary - choosing to start 2021 years ago is as good as any other point. However, since the BC/AD system has been widely used for the past 1200 years, there was no reason to change it."
],
"score": [
14,
8,
7,
5,
4,
3
],
"text_urls": [
[],
[],
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kvyrjl
|
Why does a pot of water not steam when boiling but once the heat is turned off, it becomes really steamy?
|
Chemistry
|
explainlikeimfive
|
{
"a_id": [
"gj1ic7s"
],
"text": [
"Steam is invisible. What you are seeing is actually steam cooling and turning back to water. When you turn off the heat the steam and nearby air becomes cooler allowing the steam to cool more easily and become visible water."
],
"score": [
5
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kvyw5t
|
if melting point and freezing point are both 32°F, what would happen if I put both ice and water (in separate containers) into a freezer that stayed at exactly 32.0?
|
Chemistry
|
explainlikeimfive
|
{
"a_id": [
"gj183u5",
"gj18pyn"
],
"text": [
"Assuming everything is absolutely perfect, nothing. Water doesn’t instantly freeze at 32, it starts freezing, you need to keep pulling energy out of it (and provide a place for ice crystals to form, which often is impurities but can also be the edge of the container. The ice won’t melt because to break from a liquid to a solid you need to pump energy into it. But if you’re keeping both perfectly at 32, ie no energy is entering or leaving (which in real life is next to impossible but for sake of argument) it won’t change. If you want to look at this graphically, look at a Phase Change Diagram (like the one here: URL_0 ) Notice how when water is changing from solid to liquid, or the other way from liquid to solid, the Line is horizontal while heat energy is being added/removed. That whole horizontal section is at 32 degrees, but there’s still energy entering/being removed to cause the physical state to change.",
"Water can remain a liquid just below normal freezing temperatures and remain a solid just above normal freezing. The water needs energy to force it from one state to another. Ie: solid - liquid - gas. Pure water in a clean bottle that remains undisturbed could remain in stable state, till it receives the input to change from one state to another. Look on YouTube for super cooled water. There are several good videos. Normal water has impurities dissolved inside. The water molecules can crystallize around the impurities more easily. When the first crystal forms, the other molecules can more easily start the shift which can be a chain reaction."
],
"score": [
18,
6
],
"text_urls": [
[
"https://www.aplusphysics.com/courses/honors/thermo/phase_changes.html"
],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kvzip6
|
Why isn't the amount of sleep we need continuous over how long it's been since we've slept?
|
Sometimes I try to go to sleep and just can't get into it, then an hour or two later I'm exhausted and sleep for eight hours. Why isn't it a more continuous process where the less tired I am the less time I need to sleep? Instead it seems to be that I need to hit some threshold for tiredness before I can sleep at all.
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gj1jovh",
"gj25gqd"
],
"text": [
"I don’t know the reason, but I think it kinda does work that way. So about 10 years ago I was going through a really bad point in my life. I started seeing a psychologist, who recommended a psychiatrist. The psychiatrist said I must be on the bipolar spectrum and put me on depakote. 500 mg, 2xdaily. The thing about that drug is that it keeps your brain from switching gears. So I wasn’t having any psychotic episodes, but I also wasn’t in a good mood, or a bad mood, wasn’t anxious, wasn’t depressed, All I felt was boredom. Eternal boredom. So the funny thing is depakote kept me from sleeping. For days. And days. Usually I would be up for 5 days without sleep, sometimes 7days. I was extremely delirious and I could feel shadows creeping all around me. But I wasn’t tired, just bored. Then eventually I’d fall unconscious. If I was up for 5 days I’d usually sleep for about 17 hours, then get up and start the cycle again. If I was up for 7 days I’d usually sleep for 23 hours. I’m happily unmedicated at this point in my life, but i do still suffer from insomnia from time to time",
"Sleep isn't really just a period of time where your body shuts off or refuels. It's a process that goes through 90 minute cycles throughout the duration of sleep. It involves NREM (non-rapid eye movement) and REM (rapid eye movement) stages. NREM 1 is the first part of sleep. You're still close to awake at this time, but breathing, heart rate, and muscle movements start to slow down. NREM 2 is the most common stage throughout the night. It's deeper than NREM 1 and features a further drop in breathing and heart rate as well as body temperature. However, it's not the deepest part of sleep. NREM 3 is the point where your brain actively suppresses your responses to sounds, making it hard to wake up. It's a stage that is most frequent during your first few hours. HR and breathing hit their lowest point here. Children spend more time in this stage than any other age group and the elderly spend the least. REM is the most famous stage as it's credited with being the dream stage. Here, your brain is almost as active as when you're awake. Your heart rate increases to almost the same rate as when awake and breathing becomes irregular. Most REM occurs as sort of brief peaks before you dip back into NREM 2 later in the night. During REM, your brain is sifting through what you did the day before and cutting out any information that's not needed, while further cementing important info in your memory. That's why ample sleep before a test is really important. I believe it's during the first 4 to 6 hours of sleep that your body does self-repair of muscles and other parts. If you wake up feeling sore after too little sleep, it could be because your body hasn't had enough time to properly repair. Sleep is vital to your physical health because of this. Now let's address the sleepiness threshold; yes, you do need to pass sort of a threshold. There are multiple Circadian rhythms that occur in your brain and body that all involve sleep. Certain neurochemicals and hormones like adrenaline, melatonin, and others go through daily production peaks and dropoffs throughout the day and night, affecting when you're tired and how tired you are. These rhythms are heavily affected by your own daily routine as well. If you always go to bed around 10, then your body could have issues preparing for sleep if you suddenly go to bed at 8 one night."
],
"score": [
6,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
kvzkx2
|
What’s left after a brain tumours removed
|
When a brain tumour is removed , is there just an empty space left where it was? And does that space ‘fill up ‘ agin ???
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gj1b250"
],
"text": [
"Air. Apparently after surgery patients can hear the air bubble move around *inside their brain* as they change the orientation of their head. The air is absorbed gradually by the tissue and fluid in the brain, then removed via the lungs and exhaled. The lost volume of air is replaced by Cerebro-Spinal Fluid, the liquid which normally encases the spine and brain."
],
"score": [
25
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
kw0cl4
|
My dad can crack a walnut with his bare hands. Is there something changing in muscles as we get older that makes them genuinely more stronger?
|
Even though I'm 40 and my dad never leaves couch I strongly believe that he can win easily in any strength competition (involving arm strength to be precise). Is there something biologically different in muscles as we get older that makes muscles stronger, and we don't have to exercise as much to keep them that way?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gj1ii19",
"gj1ol83",
"gj1gf1k",
"gj1hshd",
"gj1h618"
],
"text": [
"Cracking a walnut is a technique not a strength thing. Also growing muscles is something you do with training. Sure genetics play a role but getting the strength of a average 60yo isn't limited by your genes.",
"You lose muscle mass and strength by about 1% a year from the age of 50. So strong older men were stronger younger men.",
"Maybe he has a history of actually using those muscles a lot vs you?",
"Men generally have greater tendon strength than women. I've heard it called grip strength to I believe. Some guys can crush apples with bare hands ( not me lol ) but they dont look all jacked up.",
"If I had to guess, he's been able to do that for a long time. Strength peaks at 25, so if your dad is still stronger than you, you probably didn't inherit that gene from him."
],
"score": [
10,
6,
4,
4,
3
],
"text_urls": [
[],
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
kw0dxp
|
How do living things without brains function?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gj1lej1"
],
"text": [
"Same as things with a brain function; endlessly cascading chemical reactions that result in the eventual reproduction of said being. Sure, our brain is a lot more sophisticated than pretty much every other biological machine out there, but that doesn't mean they can't function. You can think of a cell's nucleus as that cell's brain, for all intents and purposes it has the same function as being the central hub that is controlling how things react around it."
],
"score": [
13
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kw0piq
|
Mike Pompeo said Al Qaeda has set up a home base in Iran. How is this at all plausible considering 1) Iran is Shia Muslim and are hated by Al Qaeda 2) Al Qaeda was largely a Saudi organization. Iran and Saudi Arabia are enemies and are actively fighting a proxy war in Yemen?
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gj1iwm8"
],
"text": [
"It’s not really. It’s unfortunately a primarily politically motivated statement. I don’t mean to excuse Iran. There are plenty of Shia terrorist organizations. However Iranian-backed militias have been fighting AQ for a long time. I will point out that AQ is not really a largely Saudi organization. Yes the Wahhabism brand of Islamic terrorism grew from, and maintains a large presence in, Saudi Arabia but it’s found wide appeal with Sunnis across the Middle East and Africa."
],
"score": [
6
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kw1gxh
|
Why do we move our eyes when thinking?
|
If you paralyze someone's eyes can they think as effectively?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gj1nmrm"
],
"text": [
"I'm not sure if there are any other reasons, but looking in a certain direction when thinking often helps to \"activate\" that side of the brain. People often glance to the left when being asked questions because the left side of the brain handles intellectual things including memory recall."
],
"score": [
4
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
kw1te2
|
Should I wash my hands with warm or cold water. Why?
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gj1psnt"
],
"text": [
"as hot as you can handle without hurting yourself. The temperature of water doesn't sanitize any better, the soap and rubbing is what removes germs, but hot water helps break down and lift any oils or greases that are on your hands, which could harbor bacteria."
],
"score": [
5
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kw1z6x
|
Rubbing my eyes world.
|
Exactly what am I seeing when I rub my eyes and everything gets all blue and purple and spotty?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gj2eyue"
],
"text": [
"Your eyes are very sensitive organs, and are filled with fluid. When you rub your eyes, or look at a bright light and get an afterimage, you’re doing the same thing in different ways: over-stimulating your retina. Think of it like memory foam. When you push on the foam, it holds the imprint of your hand for a few seconds but ends up going back to normal. When you push on your eye the fluid tries to compress and ends up pressing on the back, when you look at a bright light the part of your eye takes time to adjust back to normal. That part of your eye is “on” and holding the image for a few seconds while it “bounces back”."
],
"score": [
10
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
kw1zjx
|
How did a brain turn into obsidian in the Pompeii Volcano eruption?
|
Scientists found intact neurons preserved as obsidian in the corpse of a victim of the Pompeii eruption, somehow the intense heat preserved the brain. How did this happen?
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gj1wg9w"
],
"text": [
"The process we're talking about is called \"vitrification\", which is when a liquid is cooled into a solid very quickly so that crystals don't form. The end product of doing that is \"glass\". Obsidian is rock that melted and then cooled quickly. The hard sheen on pottery is also that. When plants/trees need to survive extreme cold weather, some of their tissues survive by vitrifying naturally instead of freezing. A fun example is cotton candy. If you melt sugar and cool it slowly, you get hard candy, but if you cool it quickly by spinning it into little strands, you get a bundle of glassy candy threads. In medicine, vitrification is also used to preserve tissues like a woman's eggs--the tissue is supercooled so quickly that it doesn't just freeze, it vitrifies into a glass. So this poor man's brain vitrified because it was melted (along with his other organs) into a liquid by the intense heat of the pyroclastic flow (deadly volcano gases) and then also cooled back to room temperature quickly. This is extremely unusual because a soft tissue like the brain wouldn't normally vitrify. This is the first known example of a brain being vitrified by heat, even from elsewhere in the Pompeii site. This required unusual circumstances which are not fully understood yet."
],
"score": [
9
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
kw2mzw
|
why does our knee have a reflex to kick when you get hit in the kneecap? any other reflexes we have like this?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gj22f33"
],
"text": [
"They exist to allow us to respond faster than we could if we had to stop to think about it. They work by essentially allowing the nerve that senses something, to fire a pre-programmed message to the muscles, without having to relay the information up to the central nervous system first. So, in the case of the knee one, the patellar reflex, it happens when the tendon is stretched, like in a way it might if your legs give out or something. So, you kick your foot out automatically to try to keep from falling. There's a few of them that we have - mostly to oppose forced movement (if your arm is forced in, it reflexes out), including one's that make our toes curl with pressure to the sole - maybe a holdover from primate ancestry to try to grip a branch. There are other ones that have to do with infancy to help us survive, that go away after your brain starts to mature. For instance, there's a reflex that makes baby's suckle when you tap their chins - which is almost certainly to help them latch on to a nipple so they can feed."
],
"score": [
12
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kw37vd
|
Why do we refer to some singular articles of clothing as a “pair?” Like a pair of pants or a pair of underwear?
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gj278zl"
],
"text": [
"Because they used to be two separate pieces with no crotch seam connecting them! [ URL_0 ]( URL_0 ) ETA a slightly more thorough explanation: It used to be that a \"pant\" (or a \"pantaloon\") was just one tube that went over your leg. You would put two of them on separately, hence a pair of pants. (And of course some of those were called *under*pants because they were worn under your real pants.) Eventually, people started to connect the two pants at the crotch and waist and make the \"pair of pants\" into one garment, but everyone was used to saying \"a pair of pants\" so the name stuck."
],
"score": [
3
],
"text_urls": [
[
"https://www.worldwidewords.org/qa/qa-pai1.htm"
]
]
}
|
[
"url"
] |
[
"url"
] |
|
kw3ijh
|
Look I'm sorry but I genuinely can't tell the difference between $2 olive oil & $50 olive oil. I've even been on a tour to explain why they're different, my brain simply - doesn't care.
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gj1znnw"
],
"text": [
"OK, so you don't care, what's odd about that? I think that multi-million dollar Jackson Pollock paintings look like paint spilled on the floor and wouldn't pay a nickel for one. So what? You're talking about your personal taste, that's not something we can explain, it's inside you. There's nothing wrong with having personal opinions, and there is no reason everybody ought to expect to think and like the same things. Humans are all unique individuals."
],
"score": [
5
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kw3thd
|
What is a polar vortex, and what is happening to it in 2021?
|
Earth Science
|
explainlikeimfive
|
{
"a_id": [
"gj255y9"
],
"text": [
"Imagine an arctic hurricane spinning in tight formation above the North pole, with super cold air. Now, it weakens and loosens up, and fragments spread further south with the super cold air, dipping down into populated areas and causing temperatures to drop dramatically."
],
"score": [
4
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kw49a1
|
Why does playing chess consume that many calories but playing videogames, which, in theory, uses a lot of brain capacity, doesn't?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gj25cvv",
"gj2i8hd"
],
"text": [
"Your brain is a huge calorie hog...thinking hard requires a lot of energy. Most videogames, however, don't actually require a lot of thinking, especially when you get good. They require a lot of \\*attention\\*, but that's not the same thing. Practicing video games is all about establishing muscle memory and reflexes so that you \\*don't\\* have to think hard, you just react. This is sometimes called getting into a \"flow state\" which is very efficient but not like the type of thinking you do in chess. There's no such thing as a \"chess reflex\" beyond a few standard openings.",
"Frame challenge: playing chess does not use very many excess calories. Those that it does use, are due to high stress. Playing a high stress, fast-paced competitive videogame, e.g. StarCraft 2, DoTA, would burn the same amount of calories, plus more due to the constant physical activity. [People have used chess as a model for studying stress responses and therefore have done a detailed metabolic analysis.]( URL_0 ) The key data is in table 1 (p. 347); here it is, converted to Calories/hr: > Energy expended (Cal/hr): Before / Beginning / Middle / End > > ------------------------ ----------- ----------- ----------- ----------- > > Mean : 91.8 / 100.2 / 91.8 / 93.0 > > Minimum : 68.4 / 70.8 / 70.2 68.4 > > Maximum : 120.0 / 132.0 / 120.6 / 122.4 > These are comparable to light physical activity (desk work, etc.), and not even close to jogging (400-500 Calories/hr for someone weighing ~70 kg). So, no, chess grandmasters do not rate that highly when it comes to caloric expenditure."
],
"score": [
20,
6
],
"text_urls": [
[],
[
"http://www.ncbi.nlm.nih.gov/pubmed/18987876"
]
]
}
|
[
"url"
] |
[
"url"
] |
|
kw4rtn
|
Classical voice training
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gj2bahk",
"gj2tbd1",
"gj2avsg"
],
"text": [
"Here are a few things that are focused on during vocal training. 1) Breath Control - being able regulate how the air is used during singing. Keep the vocal folds together and not letting breath escape while singing. 2) Relaxation of the vocal tract - basically keeping all the muscles relaxed from the vocal folds all the way through to the lips and everything in between. Your larynx (where your “adam’s apple” is) needs to stay relaxed and in a lowered position. A relaxed tongue is also super important. 3) Lots of space in the vocal tract - lifting your soft palate, (the part that flaps when you snore) making sure your tongue is always in the correct position for all the vowels that you sing on, and letting your voice resonant within your vocal tract and nasal cavity. That’s what gives classically trained vocalists their power. 4) Practice controlling the really small muscles within the larynx to access the entire vocal range - both men and women have different “registers” or parts of their voice that sound different throughout their range. (How high and low they can sing) Practice is needed to even out those register “changes” so it sounds like one fluid sound from the lowest to the highest. That’s why boys voices typically “crack” during puberty. They don’t have control over their voice and it accidentally flips to the wrong register suddenly. I could keep going but I think that’s a decent overview.",
"The big one that no one else mentioned was vowel shaping. Learning the correct lip, jaw, neck placements for producing the pure vowel sounds. Ah, oh, ee, ay... etc That's the big reason why you don't hear accents when trained artist sing, but do when you hear them talking.",
"Being \"classically trained\" to sing involves being taught how physiology (the way our bodies work) can change how you sound (watch opera singers, and how *freeking wide open* their mouths are when they sing--and how clear and *loud* they can be, even without amplification). Breath control (so you can sing for longer without getting winded), pushing from your belly/diaphragm instead of \"singing with your chest breath\" (unless you want to make a *different sound*, then you *can* sing *in a certain way* with your chest), posture, and other techniques, as well as understanding some music theory and the intentions (if known) of how the music the singer is singing are all also parts of being \"classically trained\"."
],
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12,
7,
3
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|
[
"url"
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[
"url"
] |
|
kw5fzd
|
Why does the same supermarket less than 5 miles away have a completely mirrored store?
|
Economics
|
explainlikeimfive
|
{
"a_id": [
"gj2kjch"
],
"text": [
"Supermarkets are intentionally design to make customers walk around so that they see as many products as possible to encourage impulse purchasing. This is why the dairy is always in the back, and milk and bread are kept separate. The kinds of things people are most likely to buy if they're just dropping in for one or two things are strategically located to maximize opportunities for additional unplanned purchases. Reversing the floor plan makes it so the people who shop at one store are not as familiar with the other one, increasing unplanned purchasing. Theres a whole science to how supermarkets are laid out to increase spending. Everything from where things are (such as flowers and produce by the door), what products are near other products, and which shelf certain items placed on is all planned out carefully and is driven by careful analysis of sales patterns and psychology. Using a reversed plan means they only need to map it all out once, but can still change it up for two stores in the same area. There are some interesting articles out there on the psychology of supermarket layouts if you're curious. EDIT: Here's an infographic that lays out some of the basic concepts: URL_0"
],
"score": [
3
],
"text_urls": [
[
"https://www.bestmarketingdegrees.org/science-of-grocery-shopping/"
]
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}
|
[
"url"
] |
[
"url"
] |
|
kw5hp3
|
Given how fast ruins are covered by vegetation and dirt, how can something as simple as Nico Ditch (a 2-meter deep ditch) still be visible 1000 years after it was first dug?
|
I came across this Wiki page: URL_0 The ditch was dug sometime between the 5th and 11th centuries. That's 900-1500 years ago! There doesn't seem to be any record of anyone maintaining it between now and then in any systematic way, so how is it still around? Shouldn't it have filled in with dirt and vegetation by now?
|
Earth Science
|
explainlikeimfive
|
{
"a_id": [
"gj2cj3p"
],
"text": [
"The short answer is it has. The ditch would have been much more pronounced 1000 years ago. That you still see it today is a testament to how deep and wide it once was. Edit to add after reading up on the wikipedia page there, apparently the ditch was used as a property boundary for many years after it outlived its usefulness as a defensive fortification. That would have lengthened its life and made it less likely to be backfilled, although it appears much of it has been anyway."
],
"score": [
3
],
"text_urls": [
[]
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|
[
"url"
] |
[
"url"
] |
kw5uxt
|
What is the aristocracy? Is it just rich people?
|
Economics
|
explainlikeimfive
|
{
"a_id": [
"gj2f5m8"
],
"text": [
"The aristocracy is not necessarily rich. They are a group of land owners that have some type of hereditary title within the country. This title was given to them, or to their ancestors, for some type of service they did to the crown/country. In many places, the title certainly helped them become rich, because aristocrats were often the only people that owned land; the land was a gift alongside their title. Aristocrats don't necessarily need to be rich. It was possible for aristocrats to be relatively poor. If they ran up large debts, or failed to make any decent money from their land, they could be broke. You see a few aristocrats in the UK selling off their family castles for next to nothing because they (and their predecessors) squandered their money. Being rich also did not make you an aristocrat. Members of the clergy could become rather rich, especially abbots of wealthy and productive monasteries. However, they were a part of the clergy, not the aristocracy. The main difference being that none of the clergy members had hereditary titles—they were typically not allowed to have children. Commoners could also be rich. Starting in the late middle ages and early modern period, traders and artisans could earn quite a lot of money. It was not uncommon for them to have more money than aristocrats, but since they had no title and no land, they remained commoners. To be fair, the modern usage of the word aristocrat does often mean rich people, especially in republican society like the USA or France. Technically, there are no hereditary titles in the USA (they are outlawed in the Constitution) but the rich and powerful could be described as aristocratic."
],
"score": [
9
],
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|
[
"url"
] |
[
"url"
] |
|
kw64c7
|
Help a father describe how the placenta detaches normally from the uterus
|
My seven year old daughter has been very curious about how the birthing process works. I found a good collection of educational videos online about mammalian pregnancies including humans, but none of them explain in a normal pregnancy how the placenta detaches. Does it detach when the uterus contracts after the baby is delivered? Are hormones released? All of the above?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gj2hy0e"
],
"text": [
"Your call on telling a 7-year old this. After delivery, contractions continue. Without the fluid (and baby) to fill the womb and push back on the contractions they hurt less and shrink the womb more. The placenta isn't shrinkable, or solid enough to resist the contractions (these muscles are strong). As a result, it is sheared off from the uterine wall and ultimately expelled/delivered."
],
"score": [
6
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
kw655v
|
Why does the ISS require thrusting to maintain orbit, while the moon has been orbiting the earth for a long time without any problems.
|
Physics
|
explainlikeimfive
|
{
"a_id": [
"gj2fnr8",
"gj2g6po",
"gj43iri"
],
"text": [
"Atmospheric drag. The ISS is high, but there's still enough atmospheric drag to slowly lower its orbit. Without the regular boost, the orbit would drop lower into the atmosphere and drag would keep increasing to the point the orbit gave out.",
"The Earth is 12,742 km wide and the ISS only orbits at an average height of 408 km from its surface. If you shrunk the Earth down to the size of a balloon, the ISS would only be about 0.3 inches [0.8cm] from its surface, which illustrates just how close it is to the planet. While the atmosphere at this height is very, very, ***very*** thin, it's still there. Which means that the ISS is always slowing down due to atmospheric drag, eroding its orbit continually. This is why the ISS needs a boost every now and then to push its orbit back up.",
"Just to add, the moon’s orbit is also one that is slowly moving away from the earth. In a few millennia the moon will be far enough so that eclipses will never happen again. The ISS on the other hand is on an orbit that will eventually have it fall back to earth unless it is stabilized."
],
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59,
17,
5
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|
[
"url"
] |
[
"url"
] |
|
kw6955
|
For someone who struggles with depersonalization, what are some reasons that I think I’m in a coma/dead are irrational and make no sense?
|
Physics
|
explainlikeimfive
|
{
"a_id": [
"gj2kh4u",
"gj2i1q0"
],
"text": [
"Have you seen the movie inception? The main crew keep a small item to test if they are in reality or not. When they aren't sure, they use it to confirm. Like spinning a top, or such. If you haven't seen it, it may provide some perspective and mental tricks to help.",
"If you chuck a ball in the air, it will always fall in an arch shape, but it also will fall in an unpredictable arch. All kinds of things around you have their own patterns that you can only experience if you're alive and interacting with them, our own constructed ideas of them are never quite as good, reality always surprises us. So you can just chuck a ball up in the air, try and catch it, throw it in different ways, catch it again, pay attention to how it falls, and that interaction is both only something that a living person can do, and also a thing outside of yourself that you can keep exploring if you want to."
],
"score": [
4,
3
],
"text_urls": [
[],
[]
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|
[
"url"
] |
[
"url"
] |
|
kw6mzf
|
how did elevators work before electricity?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gj2jq5z"
],
"text": [
"Believe it or not, elevators have existed since grecian times, and to answer your question, there have been a lot of methods used to use elevators: Mechanical power from humans and pack animals, steam, gear systems, combustion motors, even primitive hydraulics and water displacement (which some elvators, and the Panama Canal, still rely on). The PASSENGER elevators you're probably asking about pretty much always did run on electric motors, but mining elevators, construction elevators, and freight elevators before 1880 (when electric passenger elevators were invented) have only recently run on electricity. EDIT: Corrected canal"
],
"score": [
12
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|
[
"url"
] |
[
"url"
] |
|
kw6yxs
|
Why do different employers have different pay schedules (weekly, bi-weekly, monthly), is there a benefit for employers to have different schedules?
|
Economics
|
explainlikeimfive
|
{
"a_id": [
"gj2mdwf"
],
"text": [
"Employers choose payroll systems with three considerations: 1) not making their workers mad; 2) minimizing their costs; and 3) maximizing their cash flow. For businesses with constant cash flow, schemes like bi-weekly minimize costs. This is a common scheme, and the low-cost payroll provider no doubt supports it. For businesses with cyclical cash flow, they try to schedule expenses (like payroll) after their revenue comes in for more positive cash flow. There are limits, farmers can't expect workers to go all summer raising crops only to be paid in the fall after the harvest comes in. This would violate rule #1. Practically, they are playing this summer's workers with the proceeds of last year harvest, which impacts how rapidly they can expand."
],
"score": [
6
],
"text_urls": [
[]
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|
[
"url"
] |
[
"url"
] |
|
kw76v4
|
Why do lights flicker bofore a power outige
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gj2n5tu",
"gj2vh1k"
],
"text": [
"Typically because power outages are caused by some kind or short circuit that causes a surge in power draw before the system automatically shuts down. Say a tree branch falling knocks down a power line in your neighborhood, that power like is suddenly grounded, and massive amounts of electricity are going to surge into the ground through it pulling a surge before the system gets shut off either by an automatic system, or by actual physical breakers burning out",
"There are \"fuses\" in the line called oil circuit reclosers or OCRs. The purpose of these OCRs are like fuses, if they detect too much current, they open the circuit (killing power to the line). The difference between OCRs and fuses is that the OCRs can also automatically close the circuit, restoring power to the line whereas once a fuses opens, it stays open until someone from the power company manually shuts it again. OCRs exist because occasionally tree branches and wildlife can create a temporary short in the system and power needs to be cut before too much current melts the power lines. Once an OCR detects this high current, it opens the circuit, waits a fixed amount of time and then closes the circuit again. If the OCR doesn't detect a high current after it closes, it stays closed and power remains on the line. If it still detects a high current once the circuit is closed, it opens again. It opens the circuit three times. After the third time, the OCR stays open until the source of the short can be investigated. As an end user, you see the power go off, come back on, go off, come back on, and then go off and stay off."
],
"score": [
9,
3
],
"text_urls": [
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|
[
"url"
] |
[
"url"
] |
|
kw7qvm
|
When a sunset makes the sky purple and pink, why do photos you take of this with your smartphone always end up in reds and yellows?
|
I’ve experienced this with half a dozen phones. Even when you try to edit the photo, you can almost never recover the actual colors that were in the sky.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gj2ryqh",
"gj3bzfz"
],
"text": [
"For the same reason why an old turn of the 20th century photograph doesn't look right. It's a crude representation of what we actually see. Don't fool yourself into thinking your phone is different, it's still a crude representation. Just a better one, much better. No photo your phone takes, nor an image it displays is correct, it's a crude attempt at it. A few reasons why it is still crude though. To start with, you're viewing this on an screen. The screen can't show all the colours you can see, nor all the contrasts you can see. [See here for various red-green-blue (RBG) colour gamuts]( URL_0 ). That funny shape is all the colours your eyes can see. The colors are obviously on the screen so are washed out from what they really could be, but gives an idea. As you can see, RGB three primary colours only draws a triangle that captures part of the colours we can see. That whole thing you were taught in school about three very fundamental and fixed primary colours? A total lie. It's good enough, most of the colours we name are on there. But not all their shades, not all their hues. Some RGBs are better. Different and more pure blue, green, and red pixels can get more covered, but never all. A four primary colour based display and image would be better, but would also make displays much more expensive and files much larger. You'll note the one RGB triangle actually goes outside of the visible gamut, and its triangle tries to cover more of it. It relies on an impossibly red red, but that's fine for the mathematical storage of the image, just means you need to select values that are possible to actually display, and this imaginary extension allows for more of those. Assuming you have a display that can do it, which you probably don't. A very high quality printer, with a lot more than three primary colour inks, might be able to. The rainbow pure colours are actually the curved edge of that shape, not a single true rainbow can be show on a RGB screen. They all look wrong, faded out. The red, green and blue colours a screen can make aren't as pure as a rainbow, and anything they make through combination won't be as pure either. That means a small triangle within that fill possiblity of colours. Why do some displays look better? Because they use high quality pixels that push more to the limits of a very pure red, green, or blue on the edge, a larger triangle. And that's assuming an analog view of just colours. Digital information is stored as bits, there's jumps in it. Not only can you only go within that triangle, you can only go within a grid on it. More missed colours. Then there's brightness and contrast. Again, it's digital so there's fixed brightness steps too, not any brightness is possible. As well, a screen is limited in contrast. Blacks are a dark grey, and whites are not as bright as they could be. A high dynamic range, HDR, display can improve this, both with more bits (so more fine steps) and more brightness on the actual display output. And that's just the display and the file being shown on it, this would all apply to only a computer generated image. Next is the camera. Again, same issues doubled up now. It's digital, it has RGB based sensors. It has all the same limitations. On a phone, your display is probably better than your camera, photos taken with real cameras (or 'shopped) will look better than what it takes. Additionally, the RGB sensors are just best approximation of human cone cells. They don't have the same sensitivity to each colour, and they don't even pick up the same spectrum. Go aim your TV remote at your phone camera and hit a button, you'll see a purple glow that your eyes can definitely not see. There's IR light out there, especially from a sunset, and your camera is going to pick this up and it's going to distort the colours. Then there's more photography related tricks. There's things like white balance, focal length, field of view, saturation. Adjusting all of these makes for better photos. You with your phone are a bad photographer. A professional photographer could get a better photo by playing with these, even without better equipment.",
"Mostly white balance. The software behind your phone's camera is designed to make pictures (especially of people) look good. One way it does this is to correct for lighting in a way that imitates the way that our brains work. Without it, a face might look reddish under incandescent light but greenish under fluorescent light. Unfortunately for this to work really well, you need a large part of the picture to be a recognizable color: a blue sky or an approximately white wall. When you take a picture of a purple sky, your camera assumes that there's some funny lighting and that you want the color fixed. You may be able to get around it by manually setting the WB or by by pointing the camera at something neutral colored and holding the shutter button half pressed to keep that setting while you take the picture you want."
],
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23,
4
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],
[]
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}
|
[
"url"
] |
[
"url"
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kw7xer
|
Can glasses that make you see like mantis shrimp be created?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gj2r0m1",
"gj2u3w7",
"gj2rru6"
],
"text": [
"No. The human eye has four kinds of light-detecting cells. This limits the number of 'colors' we can see to four, but since one of these times is mostly indiscriminate to color, the number is actually three. Glasses can block out some colors that rest 'between' the colors we see, causing improved color sharpness (how enchroma glasses work), but they cannot change this basic limit of three colors.",
"The other commenters here have addressed colour perception very well and it's bad news there. There's another way a mantis shrimp's vision is special, which is that they can perceive the polarization of light. Polarized light is a weird idea. You've probably heard that light is a wave. One property that a light wave can have, is what direction it 'waves' in. Light that's coming into your eyes can be waving up-and-down, or left-and-right, or any diagonal direction in between. Or, it can be a mixture of waves waving every-which-way. Reflecting off certain materials in certain ways can make light polarize one way or another, so the polarization can tell you information about the shape and contour of what you're looking at. Mantis shrimp can see what direction the light is polarized in, because the openings of their eyes have a squiggly, narrow shape which obstructs the light in just the right way. Naturally, we can't see the polarity of light. But we do have polarizing *filters* which will 'flatten' the incoming light to only light polarized in one direction, and block any light going the other direction. And one thing we use those filters for is to make sunglasses. If you wear polarized sunglasses, you'll be seeing the world filtered so as to show you only one component - maybe the horizontal component - of the light that's coming in. The mantis shrimps can see both at once, and see different polarities of light in different ways at the same time, and wearing sunglasses you can only see one at a time. But try tilting your head from side to side while you're wearing them. You might notice that certain parts of what you're looking at darken, and others lighten, as you're tilting your head back and forth. Especially try doing it if you're looking at a lake or something like that. [eta: Anything made of transparent plastic or acrylic, is probably a good thing to try looking at too. Explore and you may find certain views where the effect is much more dramatic.] That might give you some *tiny* glimpse of what it'd be like to see polarity.",
"We have three color receptors in our eyes, able to differentiate the spectrum from post-ultraviolet to pre-infrared. Glasses aren't going to add an additional 13 receptors in the eye. Sorry. 乁( •_• )ㄏ"
],
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9,
8,
3
],
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|
[
"url"
] |
[
"url"
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|
kw8kax
|
How are animals that eat only one kind of food not horribly malnourished? Do they need a narrower set of nutrients than humans?
|
Biology
|
explainlikeimfive
|
{
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"text": [
"Animals (including humans) are able to synthesize some of what their bodies need, and the things the body can’t produce on its own need to be directly ingested. An example is vitamin c. Humans don’t produce it, so we need to eat it to avoid nasty things like scurvy. Cats and dogs need it, but their bodies can self-produce the needed amount, so they don’t need to consume any from food. To be fair, I don’t know much beyond that, but I’d guess that animals that subsist on very narrow diets probably have a combination of relatively minimal nutritional needs (in terms of mineral/vitamin diversity) and the ability to synthesize whatever different things they do need. edit: adding some additional info, inspired by several of the other comments below and elsewhere to the post. Also added a couple \"just ok\" links, which do provide some jump-off points to better sources. \"Narrow diets\" might not be as narrow as they seem to us. For example, whereas humans tend to eat mainly muscle tissue (mostly protein), carnivorous animals eat muscle + organs, which provides a lot of nutrition. Also, surviving != thriving. [link]( URL_1 ) Similar to the synthesis concept I mentioned, is a more symbiotic approach, such as that in cows. Cows eat a lot of grass, yet are able to meet their protein and nutritional needs. Their four chamber stomachs break down the grass more completely than ours, and hosts bacteria that feed on the grass as this happens, and the cow in turn ends up deriving nutritional value from the bacteria. [link]( URL_0 ) In summary, it seems like the main reasons animals get by how they do is because: they're still here. They're either specialized to process their diets, and/or we're ignorant about what they're actually getting in their diets.",
"Different animals are able to digest different things and have different nutritional requirements. Example is dogs and cats. You can’t give a cat just dog food because it lacks an amino acid that dogs produce on their own but cats need through their diet. But you can’t give a dog just cat food because it’s too high protein.",
"In many cases, animals that eat almost exclusively one kind of food will have rare diet supplementation and they actually do get all the necessary vitamins. Wild cats eat grass, even though they are carnivores. There's lots of videos of horses/deer eating mice and birds that get too close, even though they are herbivores. Or goats and other animals traveling far distances to get salt intake. Housepets will eat flies or bugs that they encounter around the house (just for a relatable example). They may not do it very often and it is a negligible part of their calorie intake, and have adapted to conserve and more aggressively absorb the rarer nutrients in their diets. Common nutrients less so - like Vitamin C, which some animals produce themselves, but our diet expects it and we get scurvy without it.",
"It’s nature. If you eat the thing no one else wants then you can eat as much as you want. For example pandas and koalas. They eat food nothing else eats, but it isn’t very nutritious, so they have to always be eating. Which is fairly common for plant eaters. And they do have health problems, it makes it hard to have babies for pandas. And unhealthy things in koalas relating to similar organs.",
"The most basic life forms only consume one thing and their bodies produce the rest of what they need. As diet diversifies, we get more of what we need. If your diet contains a lot of Vitamin C, for example, you won't be affected by genetic defects that stop your body producing Vitamin C. So, over the millennia, organisms lose the ability to produce vital nutrients and if their diets compensate, then all is well and the genes are passed on. If not, they die just like every other unsuccessful genetic variant.",
"I think most people don't realize just how high our standards are now. We, by and large, expect a safety level that is far beyond what is simply needed to stay mostly healthy. Humans can do a lot of things considered unsafe (like eating raw meat, or consuming certain chemicals, etc) and life a long, healthy life. However, with the law of large numbers, we can consider it very unsafe. For example, take something based on eating a meal. It could have a very low chance of actually getting you sick. Lets say only one in a million meals eaten produces a ugly, fatal reaction. If you eat 3 meals a day, 365/year, and do it for 100 years, that is only 110,000 meals over your life. You can do that activity every day and still pretty likely never hit the reaction. The US population is 330 Million. If everyone did that then you'd be looking at 1,000 preventable deaths a day. There have been humans who have only eaten one type of food and been seemingly healthy. Hell, there was the one guy who lost a ton of weight by not eating for over a year. Doesn't mean it is good advice for the population at large, or that you'd be advised to take whatever risks are involved. Most people would consider a 1 in 10 chance of getting severe nutritional deficiencies unacceptable, even though that means 9 in 10 people don't have problems. tl;dr: We live in an era of high standards.",
"Equine/bovine animals (like cows and horses) can survive pretty much exclusively on grass - which I assume is one of the good examples for your question. All living things consume energy. Energy is what allows the replication of cells to preserve life. Many plants survive by absorbing sunlight and converting the energy in that warm sunlight into \"food\" through photosynthesis. They also, however, absorb basic nutrients, like nitrogen, from solid particles in the soil, which supplements the energy they get from photosynthesis. They absorb these nutrients through their roots with the help of water which helps to absorb the minerals. You might think of plants as taking sunlight to heat their oven and the minerals as the ingredients in the meal they \"cook\" to \"eat.\" Animals which primarily depend on grasses and grains as food eat those plants, which have already converted minerals and sunlight into a new, more complex form of energy. The animals \"steal\" this energy from the plants, having already done a lot of legwork. These animals have specialized digestive systems and organs which produce the more complex proteins they need to develop muscle and fat, which aren't obviously available in plants (but the building blocks are there). Carnivores take this a step further and \"steal\" the nutrients from animals which already converted the energy from plants into valuable and readily available proteins (among other nutrients). This same concept occurs throughout the chain of life, with fruits and vegetables and grains all creating different concentratioms of sugars, fiber, carbohydrates (a sugar) and proteins and other basic vitamins and minerals which animals eat to quickly and easily obtain the energy they specifically need to live and reproduce. Humans generally need a wide variety of foods because we have some of the most energy-intensive processes. Our basic living functions could be sustained with some basic sugars and carbs and a little bit of protein, but we have evolved to be able to grab more of that protein through carnivorous diets, and we have successfully been able to reach a wider variety of fruits and vegetables to obtain these nutrients for such a long time. Our brains are also extremely energy-intensive and require fats, oils, and specialized proteins to fuel the specialized higher-thinking regions of the brain. Dolphins are another highly intelligent species and depend on meat for their sustenance, and because advanced predators can obtain these easily through eating meat, our bodies developed to harness that advantage and has allowed our brains to develop further than pretty much all other organisms. When an animal produces waste, there are insects and bacteria which take *that* specific form of energy and break it down even further into the more basic nutrients found in fertile soil, allowing plants to then reabsorb it in a new cycle. The abundance of specific organisms, and the concentration of certain animals producing that waste, affects the stability of that ecosystem. Grass and plants can only absorb so much of certain nutrients in a given timeframe. Same with the bacteria and insects which break down the waste of animals. All of this is limited by the availability of basic minerals and nutrients in the earth's topsoil (where small organisms can break them down and plants can absorb them theough their root systems) and how quickly plants can absorb sunlight for useful energy. So again, a recap: animals with simple diets obtain simple nutrients, and are very limited in their evolutionary advancement with respect to brain development and advanced processes. However, all nutrients are basically formed by basic building blocks, like nitrogen, hydrogen, oxygen, sodium and even metals, combined with a fuel for combining and using those minerals for \"life\" processes, which is harnessed from the sun via plants and photosynthesis in relatively large quantities. Edit: Equine is horses and bovine is cows",
"Humans are actually kind of rare among mammals in how few nutrients we can self synthesize . Vitamin C is the one I'm most aware of.",
"Yep. Human bodies are far too finicky. For eg. Lions Tigers etc can make Vitamin C and won't get Scurvy.",
"Aren't certain human peoples or tribes also like this? For example Inuit who largely eat seafood. Other peoples who survive mostly on dairy. I've heard a bunch of examples but never really looked into it. Just looked up one I heard of... cow blood. These peoole drink a lot of cow milk and blood... however looks like they eat some other stuff too. URL_0",
"There's a bit of a catch 22 where the requirement for some vitamins and minerals is higher if you consume certain foods. Many animals also have digestive systems designed to draw more nutrition out - think of a cows \"4 stomachs\". (Not literally 4 stomaches) A lot of nutrient dense food is indigestible to humans - like the whole grain of rice for example. All the good shit is in the bit we usually remove, but we can't actually digest this adequately without fermentation of some kind. Some people advocate yogurt to soak brown rice before cooking for this reason. And so much of animal food habits are about niches of availability and balance. Pandas ARE malnourished by any reasonable definition. We supplement their diet in captivity. But in their niche in the wild they're fine. The problem is that the niche is so very very specific it's not resistant to even minor change. So like, humans do not eat their \"wild diet\" which would have been very varied and included lots of things most of us simply do not eat today - like organ meats. So we have a warped world view of it being \"easy\" to become deficient.",
"I'll have a go at this- glad my metabolic pathways module at uni has finally been put to use. Though this answer will probably get lost! To approach this question, it's good to first think about how the body works. Our main function is to create energy from what we eat, and to ensure that the variety of cells in our body all function together so we can move, grow, reproduce and react to the environment. Within our cells, we have many different enzymes, which are little blobs of proteins that perform chemical reactions. The food we eat is taken apart by these enzymes to release energy, and fitted back together using energy to create other molecules, which can perform different functions within our bodies. Nutrients we eat- vitamins, carbohydrates, fats and proteins, are just a mix of mostly carbon atoms, often with some oxygen, sulphur and nitrogen mixed in. But how many atoms, how those atoms are joined together and the nature of how they are bonded dictates which molecule it is. The vitamins we eat- like vitamin b12, are used by our enzymes to either be built upon by enzymes to create different molecules, or are used by enzymes to help perform the reshuffling of molecules. The carbohydrates and fat we eat are broken down to release energy. Proteins are made of many little molecules called amino acids all joined together to create one big molecule that can form a blob shape, or a long fiber type shape. We split up the amino acids and reshuffle them to make new proteins- like being added into our muscle cells or creating enzymes. We have many enzymes in our body, each performs a different reaction. You can think of the nutrients we consume being passed through a series of enzymes, each making a little tweak and change to the nutrient, so that it can transform into another molecule. (Bare with me I'm getting to the main point!) A good example of this is essential fatty acids. Fatty acids are typically a long chain of carbons with some oxygens at one end of the chain. Fatty acids differ in the amount of double bonds present in the chain between carbons, and the length of the chain. . Each fatty acid has different roles in the body; such as being used in cell membranes; the composition of different fatty acid containing molecules within cell membranes can affect the cells function, structure and a variety of things. Neuronal cells have a very different membrane composition to red blood cells, as each have different functions. Humans have enzymes that can turn a single bond between 2 carbons into a double bond, and so turn one fatty acid into another. However, we lack an enzyme that can create a double bond in fatty acid chains past a certain point on the chain. But fatty acid molecules with that double bond that we are not able to create are still needed within our body to be used. These fatty acids will need to be eaten, as the body is not able to produce them- we have all heard of essential fatty acids omega 3 and omega 6. As humans have evolved with food sources available that provide these 2 fatty acids, we did not need to make the enzyme to create them. Our cells spending time to create the enzyme that can make omega 3 and omega 6 would be a waste of energy, because we were getting more than enough through our diet. Other animals have evolved in different environments with different foods available. Based on what foods are available, the animals body would evolve to produce the enzymes needed to take the food eaten and transform the nutrients into a variety of molecules needed in their body to be used structurally and functionally. Cats make enzymes that produce vitamin C, but as we evolved around lots of fruit and vegetables we had enough from our diet that we didn't need to bother making the enzyme that can make vitamin C. We know that vitamin C plays an important role in our body, as not eating enough causes scurvy. So cows we see eating grass- grass has a specific composition of different nutrients. Cows make the enzymes to break down the grass into everything their body needs to function. During our evolution, we ate a different diet to cows with foods that have a different composition of nutrients within them compared to grass. So now we produce a different set of enzymes compared to cows. While cows have the needed enzymes to be happy and healthy on just grass, we don't have the same set of enzymes that cows have, so we wouldn't be able to process the grass into all the different molecules our body needs to do the very vast amount of functions our cells within our body do. Sorry this is so long! It's a super interesting question.",
"Like Koalas that like only eat Eucalyptus. Like wtf haha. Smooth brains don't require nutrients lol",
"Are you thinking about vitamin c? Almost all animals synthesise that in their livers, only a few primates and a few rodents need to eat fruits and vegetables for their vitamin c",
"I feel like your question is in error. Human Chow is indeed quite possible, without malnourishment. They even sell it now: It's called Soylent. People use it instead of food all the time."
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"https://medium.com/a-microbiome-scientist-at-large/how-does-a-1-200-pound-cow-get-enough-protein-506797b53845",
"https://www.scienceabc.com/eyeopeners/if-human-health-requires-a-balanced-diet-how-do-animals-survive-on-such-narrow-diets.html"
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|
[
"url"
] |
[
"url"
] |
|
kw8xr8
|
... How do gnats just... show up?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gj2z4wo",
"gj41pg8"
],
"text": [
"A single gnat will lay somewhere between 20-100 eggs. Possibly even more. So one gnat gets in, and about a week or two later, boom, instant swarm of gnats. Also the eggs can lay dormant for a few weeks. So they can wait to hatch, though it's still a few days till the larva turns into flying gnats.",
"This doesn't answer your question But, putting a layer of sand on your potted plant's soil can reduce your fungus nat problem. It makes it very difficult for them to access the moist soil underneath to eat/lay their eggs. Around 0.5-1 cm should do it."
],
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3
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|
[
"url"
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[
"url"
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|
kw95wr
|
Why is a cancer a lot worse when it happens a second time?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gj2z7z4",
"gj328ji"
],
"text": [
"The first time it can be localized to one or a cluster of tumors. The second means it was more wide spread and/or has become more wide spread than originally thought. You can have lots of little tumors which are harder to remove. Early detection is what you hope for.",
"It’s evolution on a very small scale! Think about it like this: cancer is a bunch of cells basically going haywire and not following any rules. They’re constantly changing for the bad and for the good - while cancer cells can, for instance, multiply lots, they can have certain dependencies and sensitivities as well (these are targets for a lot of therapeutics!). The more unstable and mutated a cell is, the more likely other cell machinery isn’t working correctly putting the cell at high risk of a meltdown (apoptosis). In a treatment-naive primary tumor, the population of cancer cells is pretty diverse. Other than the immune system, the cells haven’t had too much pressure on them, lots of them can get by and continue growing. But when you treat, especially using chemotherapeutics or radiation, you’re causing mass cell death. Preferably, these treatments wipe out all cancer cells, or at least enough to prevent the residual cells from continuing on. Unfortunately, we often struggle to eliminate enough of the cancer. While the unstable and highly mutated cells can be totally wiped out, populations of therapy resistance cells that were lucky enough to get a helpful mutation are then given the opportunity to grow into secondary disease. As a result, the same treatment won’t work nearly as well, if at all. Plus, these hypothetically therapy resistance populations may be more aggressive or metastatic than the inital heterogeneous population. Please feel free to correct anything that’s wrong! I’m a PhD student studying cancer evolution and love this stuff"
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4
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|
[
"url"
] |
[
"url"
] |
|
kw9sph
|
How is Congressional censuring considered a punishment?
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gj32pib"
],
"text": [
"Its supposed to be an act of public shaming. You can certainly debate if its effective or not at this goal immediately, but censuring someone of a high level, like a President, would certainly go down in the history books with their time in office."
],
"score": [
7
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|
[
"url"
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[
"url"
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|
kw9yg8
|
Gaullism and "The Gaullism Myth"
|
I have read the wiki page and read a few articles but I still cant wrap my head around what this ism exactly means. I understand that it is a very specific thing during a specific time and maybe that's why I am having trouble.
|
Economics
|
explainlikeimfive
|
{
"a_id": [
"gj33ruk"
],
"text": [
"Gaullism is French nationalist movement where the French saw themselves as a both a historical and current exceptional power, and should focus on themselves. This would include avoid getting into free trade agreements with other countries, allowing French colonies to split away because they were a burden to mainland France, etc. Gaullism called for a strong central power, where the French president had a lot of control over the country and the executive was stronger that the legislative. To support these ideas, Gaullist historians like to focus on moments in history that put France above the rest of the world. These traits seems fairly right wing, but also included leftist elements such liberal views on the economy, trade unions, and stuff like that. In other words, it was an ultranationalist movement, but one that wasn't really far right like other nationalist movements of the time. It wasn't \"we want to conquer to the world\" nationalism, but more like \"we want to control out or own faith\" nationalism. I am not sure what the myth part is suppose to mean. Maybe the myth is how Gaullists tried to portray France as shinning star in history, which is certainly an exageration."
],
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|
[
"url"
] |
[
"url"
] |
kwaf34
|
If coordinates use minutes and seconds because of the Earth’s rotation, what do they use for other planets and why?
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gj35d0b",
"gj35ijw"
],
"text": [
"Coordinates use minutes and seconds because that's how we chose to divide angles into smaller segments. It is because earth is round, and has nothing to do with earth's rotation.",
"They don't use minutes because of earths rotation. Then we would need to split earth in 24 hours first to make it match rotation, but we split it in 360 degrees before. \"Minute\" just means \"reduced\" (related to \"minor\") while seconds are named like that because they are the second time you divide by 60. (Originally called Minuta Secunda in Latin) So both just mean \"divide by 60\" once or twice wich is the base of the babylonian number system."
],
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13
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|
[
"url"
] |
[
"url"
] |
|
kwal8w
|
How are standard adult dosages for medicines determined when each body has a unique composition and reacts differently?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gj36iua"
],
"text": [
"In sciences, there's a tendency for things to trend towards the average/mean. Most people are 'average'. They aren't so unique or exceptional that they require special considerations - and if they do, these considerations are accounted for. Drugs have what's known as a therapeutic index, which basically measures how lenient you can be with dosing and still have it do what you want it to do but not cause any significant side effects. The wider this index, the more lenient you can be. It's the space between the dose needed to be effective and the dose needed to cause an adverse effect. The closer the space (or the narrower the index), the more the need for titration/adjustment, which is where you're started on a dose and it's slowly increased until its effective. These usually have a dosing scheme based on your body weight or kidney/liver function or some other measurement. Some drugs may have a standard dose and then titrated until its effective but not causing adverse effects. Kids vary a lot in weight throughout their growth so you have to be especially careful with their dosing. This is why when kids take medications, there's a chart telling you how much they should take if it's an off-the-counter drug."
],
"score": [
9
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|
[
"url"
] |
[
"url"
] |
|
kwamb7
|
How do nature documentaries avoid disrupting the animals?
|
Other
|
explainlikeimfive
|
{
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"text": [
"You try to be unobtrusive when you're filming, and you can use concealed cameras, but sometimes they just have to go in and shoot for days, or weeks. The first several days, the animals are noticing you're there, and they're weirded out and you get bizarre footage of animals staring at you. But if you're in the same spot day after day and you never bother them, eventually they decide you're not interesting and they get back to normal behavior, and now you can get footage that's actually a decent representation of the animals.",
"A variety of ways and sometimes not at all. Extremely long zoom lenses can allow crews to film from a considerable distance. Automated cameras can be placed in carefully selected locations and record without anyone being near and so on. Animals are largely very predictable. They're habitual, we know what they want and need. So rather than running around trying to catch them on camera. We can set up and watch places like watering holes, popular trails, resting places and so on. But it's also important to understand that wildlife documentaries are highly edited. They're edited to give an accurate picture of reality but the way they do that is very manufactured. For instance, when lions hunt, most of their hunts end in failure. And the hunts that do succeed can cross a lot of distance very quickly as the animals run and chase. That makes it very difficult to film from start to finish. So when you see a lion hunt in a documentary, you might be looking at footage from dozens of different hunts all edited into a single running scene. It's an accurate depiction of a hunt but it's not like you can tell that the lioness that leaves the resting place isn't the same one that runs after the zebra or brings it down. In a similar vein, many shots of small subjects like two insects mating, are often filmed in entirely artificial settings. Often the documentary makers build tables covered in plants in a greenhouse studio setting and then introduce the insects hoping they'll do what they do. The insects still show their natural behaviour because they really don't have the ability to differentiate between an artificial set and their natural environment. And sometimes the animals do get disturbed and that's likely footage you can't use. [For example, here's a polar bear examining a plexiglass camera position.]( URL_0 ) The camera position was set up to watch a seal breathing hole that bears use to hunt. But this one was more interested in the cameraman. [Here's a fun article about a cameraman who specializes in filming insect behaviour in artificial sets for documentaries.]( URL_1 )",
"They use telescopic lenses, so they can film from far away. If they are showing you up close action it is probably staged. I did a snake-handling course a while back and the guy said one of his biggest incomes was doing nature documentaries. He had a huge collection of poisons snakes to milk for the production of anti-venom. He explained how he would let the snake slither through a pipe so the head came out the other end so they could stage the snakes' movement for documentaries. Just move the pipe around and keep the dangerous end away from people. It then all comes down to angles and editing. We have a lion park just around the corner from us with some almost tame lions. Only killed a few tourists who they didn't know. These big cats have also been hired out to shoot documentaries. They will drive them to a location that looks good and put down a horse carcase film the lions eating it. Then again mounted cameras, clearly placed cameras, clever editing and camera angles you have some footage of lions on a kill. Not all documentaries are shot like this but if it is close up overly likely they are using captive animals who are used to being handled. As stated elsewhere, animals also have routines that are easy to follow. In the national parks here in South Africa, the game rangers also know how to track and locate animals. They do this for a living, it can take them a few hours to track down a target. As the animals become used to vehicles they no longer take notice and it becomes easier to use vehicle-mounted cameras to film them. I have been on game drives where I could reach out with my hand and touch rhino, elephant. and other antelope. We were that close. These animals are so conditioned to the vehicles the game rangers use its easy to drive right into the middle of the herd. Yet if you climb out of the vehicle or move too much the animals become disturbed. They can become aggressive and attack. We have been chased by lion, rhino, elephant and buffelo before. It is easy to get really good shots if you film in situations like this. Not hard at all."
],
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"https://www.youtube.com/watch?v=9G1aHkLHQ2I&ab_channel=AnimalChannel",
"http://retouchist.net/blog-1/2016/7/12/have-you-ever-wondered-how-some-nature-documentaries-are-filmed"
],
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|
[
"url"
] |
[
"url"
] |
|
kwaxgy
|
What causes the difference in taste preferences?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gj3ab0q",
"gj3c1zu"
],
"text": [
"Your body needs different nutrients at different points in your life. Sometimes you might feel the urge to eat a specific food it might be the fact that your body needs the nutrients that that food contains. Ex. Some people hated tomato soup when they were young but now they love it because fresh tomatoes contain several carotenoids, particularly *lycopene* which very few items contain (watermelon, apricots, pink grapefruit). And that might be what your body is missing so it makes you want to have tomatoes. I hope I was of service.",
"It has a lot to do with not only cultural upbringing in terms of food but also with what you eat a lot. Your body customizes itself to so many variables in life including chemicals (enzymes) for food digestion, meaning that if you eat more vegetables, your body will produce more of those enzymes and you will become more sensitive to the taste of them, as in experience flavor deeper. Some things will be turned down a notch, like spiciness/hotness as your body becomes more accustomed to it so you could, technically, progress from a jalapeno to a California reaper if you were so inclined..or crazy. Also, if you don't eat a specific food, your body will stop producing those useless enzymes, waste of energy. So vegetarians and vegans do literally feel sick after eating an animal product because their bodies lack chemicals needed to digest those things."
],
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10
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|
[
"url"
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[
"url"
] |
|
kwblvc
|
Why is there a residual taste of the fizzy drink it contained (e.g. Mountain Dew) when reusing rinsed plastic bottles for the first few times?
|
Chemistry
|
explainlikeimfive
|
{
"a_id": [
"gj3pgdi"
],
"text": [
"Same reason tupperware becomes semi-permanently stained by tomato sauce, plastic is permeable to an extent (which varies depending on the type of plastic and molecules it's being exposed to), artificial flavouring molecules are absorbed into the plastic during the time it's in contact with a highly saturated solution (the soda) then released when it comes in contact with a less saturated solution (the water)"
],
"score": [
8
],
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|
[
"url"
] |
[
"url"
] |
|
kwbtx6
|
How does Bethany Hamilton (from Soul Surfer) not go in a circle when she paddles her surfboard?
|
If she only has one arm, wouldn’t the board just keep going in a circle instead of a straight line out towards a wave?
|
Physics
|
explainlikeimfive
|
{
"a_id": [
"gj3czec"
],
"text": [
"It’s possible to move the one arm in an “in and out” arc during each stroke that compensates. If the one arm angles so it sweeps under the board it will counter the torque applied by the rest of the stroke. I’d imagine it’s not easy but not impossible. It’s also possible to paddle a canoe in a straight line without switching sides. You do kind of a J shaped motion at the end of the stroke that again opposes the torque from paddling on only one side."
],
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3
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|
[
"url"
] |
[
"url"
] |
kwc2rz
|
Perfect silicon spheres were developed to redefine the kilogram because the platinum kilogram was changing in weight even in extremely strictly controlled physical conditions. If dust can ruin the platinum kilogram, why are people allowed to touch the silicon version?
|
How is it that the sphere doesn't become 'contaminated' with extra atoms from skin, clothes or even breath? Or is it just that these contaminants are very easy to clean off afterwards?
|
Physics
|
explainlikeimfive
|
{
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"text": [
"Not sure about silicon spheres, but the kilogram is now defined in terms of fundamental constants rather than a lump of something. The definition is in terms of the Planck constant, the speed of light and the atomic transition frequency. A lump of something is simpler, but as you note, is prone to changing over time.",
"As I understand it, because the silicon version has done it's job. The kilogram was the last SI unit that relied on a physical object as a reference point. The platinum kilogram was just that. It was a kilogram. The silicon spheres were a tool to help define Avogadro's number (a constant that links the mass number of a chemical to it's weight in grams) to the required accuracy. By doing this, the Kg could then be redefined as a mathematical formula based on universal constants, rather than \"that block of platinum in the vacuum chamber in France\".",
"Because the sphere themselves were not the new kilogram they just have 1k of mass for measuring purposes, the real definition of the kilogram is calculated with physical constants. so if the spheres are lost or destroyed it doesn't matter.",
"It’s important to note that they didn’t want to create just any sphere, they wanted to create the closest thing to a perfect sphere as physically possible. If you can create a perfect(or sufficiently close to perfect) sphere, and the material you make it out of is solid and pure, then using the density of the material, it’s volume, and knowing the molecular mass of the material (in this case silicon) you can get a sufficiently accurate measurement of the number of atoms in that object, and therefore how many moles are in that object and then you can call that object’s mass the kilogram, and then you can define the kilogram in terms of Avogadro’s number.",
"They designed the sphere because they didn't want the kilogram to be based on a physical URL_1 they made the sphere so that they could calculate the number of atoms of silicon in it, it is made up entirely of silicon 28. Kilogram is now defined by planks constant. You could watch an amazing video by veritasium - worlds roundest object. URL_0",
"Veritasium has great videos on both [the Silicon sphere]( URL_0 ) and the [new Kilogram definition]( URL_1 ).",
"The silicon version is no longer the definition of a kilogram. It's more like an example of a kilogram. If it gets some dust, we can accurately measure how un-kilogramatic it is because we have a non-physical way of describing a kilogram"
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],
[
"https://www.youtube.com/watch?v=ZMByI4s-D-Y",
"https://www.youtube.com/watch?v=Oo0jm1PPRuo"
],
[]
]
}
|
[
"url"
] |
[
"url"
] |
kwccfl
|
What is the difference between utilitarian and deontology?
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gj3fh3y"
],
"text": [
"Deontology is based on a series of ethics, kind of moral rules, rights and wrongs, if you will. They are based in various theologies (see; kants universal maxims, etc) and inform what is considered the ethical greater good/outcome in this philosophy. Is it informed very heavily by a bunch of people's ideas of what is moral/good and is hugely variable. There are very old school ethics and more contemporary ones. This variability means it's hugely subjective and one can pick and choose which deontological philosophy to apply. Utilitarianism is based on consequences....decisions are made to ensure the consequence always = the greater good of all outcomes. It is relatively more objective however still open to philosophical discussion because there are many philosophical layers when determining the net good of an outcome. This ethic is applied on a case by case basis and there are no other rules or moral obligations to guide your decision other than purely maximising good for the greatest amount of people"
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kwciju
|
How can we witness a galaxy's death as it's happening when the galaxy is 9 billion light years away?
|
Physics
|
explainlikeimfive
|
{
"a_id": [
"gj3g62g"
],
"text": [
"We can't. We're witnessing it 9 billion years later. It takes 9 billion year for the visual of that galaxy's death to reach us. What you see when you see a galaxy dying is the image of what happened eons ago. Funnily enough, it mean that a dead galaxy still impact many other billion years after its death."
],
"score": [
5
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kwclnq
|
Why do humans have to cook their meat, but no other animal needs to?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gj3iqfe",
"gj3h4jb",
"gj3he6j",
"gj3h358",
"gj3jxd4",
"gj3hh85"
],
"text": [
"Humans are an evolutionary oddity to an extent! Meat became more predominant in our diet as early hominids developed more complicated societies that could hunt with more success. It's not super usual for animals to cross from vegetarian to carnivorous diets like this. Note we lost our big ape-guts, which monkeys need for processing crude vegetable matter because we learnt to cook things, meaning food we consumed was more readily digestible. This is why folks on paleo diets need to eat sooooo much veg, our bellies aren't great at extracting raw nutrients. Humans CAN subsist on raw meat but it must be very protein rich, brain and organs especially. Dogs can subsist off much leaner meat because they have been carnivorous forever. There is a theory that humans and wolves came together because humans were discarding the lean meat from the carcasses they killed. Wolves began to follow humans because of the cast off meat & gradually we began to work together. How nice!",
"Your body will process raw meats just fine. We cook meats to prevent food borne illnesses. Many of these illnesses are due to the way modern meats are butchered, stored, and sold.",
"We don't *really* need to; we eat carpaccio and sashimi, for example. I think there are a couple of factors: the meat we have access to is rarely freshly killed, so there is an additional risk of bacterial spoilage (along with other risks, like parasites); and we also have the luxury of eating ideally (\"can't eat that, you might get sick\" isn't going to dissuade a starving animal). Plus, our bodies have probably evolved a bit alongside our capacity to cook meat, so our digestive systems may have changed to become more efficient and flexible but a little less resilient.",
"Because we are vulnerable to illnesses from raw meat such as salmonella from chicken .But big cats, they have stomachs with stronger acids and more enzymes which help them properly break down food and also kill bacteria in the raw meat. Also animals eat fresh meat, so the flesh hasn't had alot of time to pick up bacteria. To summarise: animals have evolved to have better stomachs which allow them to easily digest the food",
"eating fresh raw meat is perfectly fine, in most cases. however, most meat humans eat are far from fresh. they have been stored for weeks/months, giving bacteria plenty of time to grow. so it's best to cook it to reduce the possibility of getting sick. however, certain meats like steak, you can eat raw perfectly fine, as long as you sear it and kill any bacteria on the outer layers.",
"Humans don't have to cook all meat, we still do eat some raw meat sometimes, but the odds of getting sick are greatly reduced through cooking, it tastes better, and nutrients get aborbed better as well. Many theories pose that the stomach biome in earlier humans was a lot stronger and has since weakend after learning to create fire and we started cooking meat for thousands of years and / or cooking even evolved us into having bigger brains and split us off from other primates."
],
"score": [
13,
11,
6,
4,
3,
3
],
"text_urls": [
[],
[],
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kwe16f
|
how does Parkinson’s work? does it happen when you flex certain body muscles?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gj3nxgq"
],
"text": [
"Parkinson's attacks the neurons and nerve receptors in the brain. It causes a rapid decay and alters the natural cycle of death and rebirth our cells naturally experience (although this decays as we get older). Because of this as our neurons, the cells responsible for sending movement signals to our muscles, become impaired and unable to perform to what we want them to do or create dopamine, a reason for the movement issues (like trembling). The rest of the mind hasn't deteriorated yet as fast as the muscles so it creates a very clear disjunction and acute awareness that the body isn't doing as it is told. Parkinson's also impacts the nerve endings that produce norepinephrine, this is the main chemical responsible for maintaining the sympathetic nervous system that moderates blood pressure, heart rate etc. This loss explains the digestive and fatigue issues regularly recorded and stated. Parkinson's is a horrid degenerative disease and I hope that noone you or I know experience it."
],
"score": [
10
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kwecms
|
Why does alcohol relieve anxiety?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gj3oxre"
],
"text": [
"Because your brain gets poisoned so you don’t give a damn. They day after is a whole different story A more specific explanation can be this: (google helped me) Alcohol is a sedative and a depressant that affects the central nervous system. At first, drinking can reduce fears and take your mind off of your troubles. It can help you feel less shy, give you a boost in mood, and make you feel generally relaxed."
],
"score": [
3
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kweqbk
|
Why do E-commerce companies have a 30-day return policy?
|
Economics
|
explainlikeimfive
|
{
"a_id": [
"gj3r69r",
"gj3r843"
],
"text": [
"They can, unless they are in a location that has laws to the contrary. Many consumers are used to 30 days though so why would they change that?",
"Because of various rules and regulations. It really depends on where you live as well, as its all different. Broadly speaking though, most shops have a mandated return period. With online shops they also have to take shipping into account as well. So let's say your brick and mortar down the road had a 14 day return period. But they also sell stuff online. Because of that they add another 14 days to the return policy-- 1 week for it to ship to you, another week for you to ship it back to them. 30 days is a nicer round number, so they go for thirty. Now, they *could* say \"14 days if you bought in store, 30 if you ordered online\", but that makes the policy more confusing. Plus, if the shop next door only does 14 days, but you do 30, you'll get more customers! Customers like longer return periods, and assuming you're selling quality goods, it doesn't hurt your bottom line as a business. Of course, if you're in the UK for example, the law says 30 (as a minimum) , so that's why they do it."
],
"score": [
4,
4
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kwf4m9
|
The Central Intelligence Agency released old UFO documents. Why do the documents look they way they are? The text appears to be un-carefully printed or just ruined.
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gj3te4v",
"gj3tn3v"
],
"text": [
"The look is due to the way that government documents in the US were typed up on a typewriter - they had to follow a very specific format. The little dots and \"smudginess\" to the document is due to multiple copies being made of copies being made of copies and the wear/degradation of paper over time. You have to understand that most of these documents were not specifically created to be of any soft of archival quality. The typewriters, paper, and storage facilities were all purchased from the lowest bidder on a contract.",
"from the few that I've glanced at I would say - they pre-date using computers for word processing so were typed - typed letters were generally less crisp - especially if the type was worn and/or dirty - they might have been photocopied - again photcopies were less crisp years ago. - they might also be carbon copies and/or copied using a mimiograph/ronegraph/gestetner style machine - finally they do have the look of documents that have been stored on microfiche Every one of these processes is less crips and clear than modern printing - and if the document went through several - eg a carbon copy that was then put on microfiche - then the issues are magnified."
],
"score": [
7,
4
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kwf9rl
|
How come some fruits ripen after harvest and some just rot? Is there a way to know which fruits will fall in which category?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gj3y9tk"
],
"text": [
"So in terms of ripening, there are two types of fruits- climacteric and non-climacteric. The difference between the two lies in a chemical called ethylene (specifically ethylene gas), which converts the naturally occurring starches in the fruit into sugars. Blueberries and strawberries, for example, are non-climacteric and contain very little ethylene, so that's why they decompose into mush after extended time off the vine. Pears or mangoes, however, are climacteric and contain significant amounts of ethylene which makes them become sweeter over time. [Here's a little article about it I found]( URL_0 .) Hope it helps 🙂!"
],
"score": [
20
],
"text_urls": [
[
"https://madison.com/wsj/news/local/ask/curiosities/curiosities-why-do-fruits-such-as-peaches-and-melons-stop-ripening-when-they-are-cut/article_2efcffd2-03c1-11e1-b065-001cc4c03286.html#:~:text=Fruits%20that%20can%20ripen%20after,into%20sugar%20even%20after%20picking"
]
]
}
|
[
"url"
] |
[
"url"
] |
|
kwfjtx
|
What is the difference between a $10 HDMI cable and one that costs $100?
|
I know that a $100 on could be super long, but that’s not what I’m asking. Why is one 3ft cable $10 and another brand for the same length is $30?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gj3ulmj",
"gj3ul1h",
"gj3wneo",
"gj3vwuw"
],
"text": [
"Branding, mostly. And for the really expensive ones, there might even be gold contacts in the cable. It’s very much a means of taking money from stupid customers; no-one’s realistically going to tell a $10 cable from a $30 cable from the screen. The only relevant difference between the two, last I checked, is the brand stamped on the cable.",
"There are different hdmi versions, as far as I know its 1, 1.4, 2, and 2.1. They could also be gold plated which will make them resistant against oxidization. The newer ones generally have a better refresh rate and are capable of 4k. Many of them are overpriced though, the most expensive isn't necessarily the best.",
"On paper ? a higher quality cable has better soldering, thicker wires which can support more bandwidth, a mash or metal film coating over the cable bundle to filter out external interference. in reality ? as long as its certified for the HDMI revision you want to use it for and your device is less then 5 meters from the TV, you´re wasting money getting anything else then the 10 buck cable as long as its certified for the HDMI version you need. For longer distances you might need shielded cables.",
"Just watched a market place review on cheap and expensive cables. The gold or platinum coating is just a gimmick and does not improve anything. They found that there was no discernable difference between cheap and expensive cables. There was a note on longevity and functionality, will it be moved regularly, swapped between ports regularly or does it have to bend into certain places. However this was not tested, but discussed as a consideration. I do know know about different generations of HDMI and their cables. From my experience, if there is a generational difference, it will be clearly labeled on a specs in the small print on the back, rather than a big advert on the front."
],
"score": [
10,
7,
3,
3
],
"text_urls": [
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
kwfxoo
|
How do archaeologists know that trepanning happened when the cavemen were alive? They could have died, their skin rotten away, and their skulls - some caveman's art project.
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gj3wfex",
"gj3xnrw"
],
"text": [
"Because when bones have been broken in some way and then healed you can see that, so the trepanned skulls have the round hole, with regrown bone around them.",
"Bones will grow back over a long time. This is how a fracture will heal up over time. The process is slow and it only grows back a few millimeters a year. But it does take place. So we can clearly see when a fracture is healing as it grows back in a perticular way that cause it to be more rounded. And any microcracks which forms as you fracture bones will be healed within a very short time. Living bones is also quite different from dead bones as there is a lot of soft tissue making up the structure of the bone. So if the bone is fractured long after the person is dead then it will look differently. This is quite facinating science which is used by archeologists to date different fractures in bones from historical sites. We can tell what caused the fractures and how long before death it was made or if it was made after death. A fracture can therefore not have been lethal or made after death if there is significant signs of bones growing back which would have required years."
],
"score": [
17,
7
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kwg6lf
|
Please explain to me what is unhealthy about drinking diet soda
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gj3y7f0"
],
"text": [
"Answer : The chemical alternatives to sugar (engineered to trick your taste buds but provide fewer calories) are carcinogens in high quantity. You die of cancer, not diabetes."
],
"score": [
4
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kwg7xf
|
Why did the ice clear my pond?
|
My pond was quite murky, then one day it froze over and the water is now crystal clear why?
|
Earth Science
|
explainlikeimfive
|
{
"a_id": [
"gj42wsl",
"gj46nk9"
],
"text": [
"Most likely the ice on top slowed the turbulent action of any wind, allowing the suspended matter to settle out.",
"Clear ice forms in very specific circumstances. The day and night must be calm, the day time temperature must hover just above freezing, the night time temperatures must plunge below freezing quickly. This forces all the particles in the water down towards the pond bed and forms a smooth surface above that is crystal clear"
],
"score": [
5,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
kwhdh7
|
How do cameras work? How did someone figure out that you could capture an image on film?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gj45r1n",
"gj45mvn"
],
"text": [
"Before we had plates to capture the image and keep it, there was something called a camera obscura, basically just a dark room or tent with a tiny hole. If done correctly, light shines through the hole and creates an image on the wall. The camera as we know it is kinda a shrunken version of this \"The History of Camera Obscura and How It Was Used to Create Art\" URL_0",
"We've had rudimentary 'cameras' for thousands of years - modern photography is just the slow evolution of that technolgoy. Some believe the [camera obscura]( URL_0 ) was invented as early as 1,000 BCE. The camera obscura is a small hole in a wall or tent that projects an image onto the opposite wall of a darkened room. While quite interesting, it isn't an amazing technological leap - it is really just a hole and that could have been invented by accident. Painters have used the camera obscura for art since its invention, tracing and painting over the images projected by the camera obscura. Once we discovered photosensitive chemicals - chemicals that would change color based on exposure to light - it didn't take long for people to start trying to use the camera obscura on these chemicals. Once they figure that out, modern photography was born."
],
"score": [
3,
3
],
"text_urls": [
[
"https://mymodernmet.com/camera-obscura/"
],
[
"https://en.wikipedia.org/wiki/Camera_obscura"
]
]
}
|
[
"url"
] |
[
"url"
] |
|
kwhhhl
|
Why does the water temperature in the shower change when a toilet is flushed?
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gj457az"
],
"text": [
"The shower has both hot and cold water running to a mixing valve. Depending on how much cold vs. hot water you let through the valve, the temperature of the shower changes. When you flush the toilet, there is a short drop in cold water pressure. This allows more hot water to get through the valve in the shower, increasing temp. Once the toilet is done flushing, the water pressure is restore to normal and the temperature corrects."
],
"score": [
10
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kwhigv
|
Why is data protection and cyber warfare considered the most imminent threat to humanity?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gj47als",
"gj4bbpl"
],
"text": [
"Algorithms for websites goals are to keep you using their platform or service for as long as possible. So in a search engine it's goal isn't to show you the most popular links, or the best answer to your questions, but what it thinks you will like and click and what will get you to come back. And usually that is either the most popular link or most accurate answer but sometimes it's not, and that's where the issue is. For example, years ago if you googled, \"Did the Holocaust happen?\" or \"Was the Holocaust real?\" it would only show posts that said the Holocaust didn't happen because the type of person that is searching this question is statistically more likely to want the results to say no. Or during elections if a Democrat googled \"Donald Trump\" you would get vastly different results than if a Republican search the same thing. Because it's showing you things it thinks you will like. And if they didn't know if you were Red or Blue they could see if you lived in a dominately Red or Blue area and guess the likelyhood of your affiliation. Or based on your previous clicks, previous purchases, music you listen to, youtubers you subscribe to, basically they can build a profile of what you would interact with based on the data they collect. And because they can reference your data with data they get from others they can see how likely their tactics will work on you. Now they are trying to be more active on the quality of the results not just if it's something you will click but these things happen all the time and add up. And so you can have a completely different sense of reality based on your internet experience",
"Data protection is good, so that's not a threat to humanity at all. Cyber warfare isn't going to kill any humans any time soon, because humans can live without electricity. They can't live where and how we live today, so there will be some losses no doubt, but many, many humans will survive. The threats to humanity are: Global warming, Nuclear war, and rogue biotechnology. These are the three things that hold some possibility of killing **all** the humans on this planet. There is also some really unlikely natural disaster stuff, but most of the risk is to man-made disasters. There is active debate about the relative risks of these three, but that's all subject to many, many unverifiable assumptions."
],
"score": [
4,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kwhj5m
|
what happens to the body moments before we die of old age?
|
Biology
|
explainlikeimfive
|
{
"a_id": [
"gj45qnh",
"gj45mc4",
"gj47j9j",
"gj4u8di",
"gj5hb40"
],
"text": [
"“Old age” is a general category for a wide number of more specific age-related organ failures. When media says someone died “of old age” they really mean “this guy was 89 years old and had a large array of age-related health issues. Nobody bothered to do an autopsy, he had been infirm for a long time.”",
"There's no such thing as dying of old age. It's what adults tell kids to be nice and soften the blow. There is always a disease, illness, disorder, etc at the root cause of why someone dies. In fact one day we will cure all diseases and illness and basically cure dying of old age.",
"As others answered the old age part, I’ll answer the other: Essentially, one necessary part of the body such as the heart shuts down and fails to start again, causing cascading organ failure throughout the body. Once the lungs shut down and energy is no longer provided to the brain at all, all electrical signals in the body halt. Shortly after that, rigor mortis sets in as the muscles lock in place. Usually prior to this the bowels clench, releasing their contents. After this, the body is out of homeostasis as the immune system has shut down, and the bacteria in the gut, appendix, and outer surfaces begin to devour the body.",
"\"Old age\" isn't really a specific cause of death. The phrase describes someone who, due to the natural progression of old age, is unable to recover from events that younger and healthier individuals may have. If I get a cold, I'll get the sniffles and be fine. If a 95 year old man gets a cold, he may develop a mild pneumonia. Because of his age and fragility, he may need to stay in bed to recover. During bed rest, he gets up to use the restroom, but he's weakened by his bedrest and already has poor balance. He falls and breaks his hip. Now he has a cold, a mild pneumonia, and a broken hip. He's 95, there's no way they consider surgery. He has that broken hip for the rest of his life. Now he's sedentary, maybe he throws a DVT and dies. Maybe he gets MRSA in the hospital and dies. Maybe the pneumonia worsens and he never recovers. Instead of saying \"well, it all started with a cold...\" and telling the whole story, people just say he died of old age because, really, he *did* die of old age. A cold wouldn't have killed him if he were younger. He wouldn't have needed bed rest if he were younger. He wouldn't be as prone to falling, or have bones more prone to breaking, or be unable to withstand surgery. In the ER, when we'd see very elderly folks die, we'd describe it amongst ourselves as \"too many years\". They're dead because, at the end of the day, everyone dies of something. They technically died of heart failure, or an aneurysm, or of a stroke, but really it's just a numbers game. Once you get enough years under your belt, one thing or another will end up doing you in.",
"As an ICU nurse that has watched and assisted many to pass as pain free as possible, moments before death many things happen. Usually, the first thing to happen are the muscles in the body become so weak that they can no longer expand the lungs enough to oxygenate the body. When the body becomes hypoxic, extremities become cold and pale, as the body is trying to preserve vital organs by subverting blood from the limbs to the organs. By this point the kidneys have failed and urine has dried up. The toxins not being expelled by the urine are now circulating through the arteries and infecting everything, causing the heart to have irregularities to its beat. The body goes into compensation by trying to hyperventilate, without effect, but to the nurse and family at bedside this looks like the patient is struggling to breathe and perhaps that they are now fighting for their life. But the brain activity is pretty slow at this point in the hypoxia and the brain stem is only acting in the way it was designed to survive. The patient is essentially brain dead. There may be a flickering of synapses that open the patient’s eyes but they are not there. The Sino Atrial node that fires electrical impulses to keep the heart beating begins to fail causing the heart rate to fail and become highly irregular. The arteries throughout the body lose their constriction which drops the blood pressure to zero by the end. Being in the ICU, I have not witnessed too many people lose their bowels after death. I can remember one, but it wasn’t much. The sphincter loosens and anything towards the end will expel itself. It’s not a big deal. Time of death is announced once it is confirmed there is no heartbeat or breath sounds for at least a minute. It’s usually pretty obvious by grey/purple skin tone and lack of any movement. Watching this so many times, especially now that COVID takes them much faster, I fully believe in the power of medicine to help facilitate this passing. If your death is imminent, let it at least be pain free. That is one thing we really don’t know. Can the dying feel the pain of death? My patients only ever felt this possible pain for a few moments as I pushed as many medications as were available to me to assist in comfort. Hopefully this answers your question in a science-y way! 😄"
],
"score": [
14,
3,
3,
3,
3
],
"text_urls": [
[],
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kwhwf0
|
When a fragile object such as a glass or porcelain bowl is bumped/dropped almost hard enough to break it, is the tension in the object somehow conserved so that it will break more easily next time? Or can it take just as much force as before the initial drop/bump?
|
Physics
|
explainlikeimfive
|
{
"a_id": [
"gj49fg4",
"gj4s8fh"
],
"text": [
"If you're making stained glass you mark the break line with a scratch which causes stress in the glass and means the fracture will follow that line. HOWEVER, you only have a short period of time to make that break or the glass settled back down into a lower stress state. So, if you drop a bowl twice in quick succession you might be able to build up a cumulative effect, but in the longer term that stress will dissipate.",
"The strength of glass is dominated by the size of the imperfections. If you exceed the strength of the glass it generally fails catastrophically (it shatters). It is possible to hit glass hard enough to produce imperfections, but not hard enough to make it break, but it is hard to do. In general glass does not fatigue like metals. If you bend metal back and forth you create and extend little cracks. Each time the stress (force) on a metal is released, the area around the tip of the crack yields. So it takes a little different shape. The material yields (takes on a bend at large scales) rather than breaks. So the metal heals a little bit each time, but never all the way. As a material gets harder and harder, it is able to yield less and less. So the force required to break it, comes closer and closer to the force required to cause it to yield. For all intents and purposes, for glass these are the same point."
],
"score": [
6,
5
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kwinbz
|
What is higher order function in Computer Science?
|
I'm self-studying Computer Science. One of my study stuffs mentioned higher-order function and didn't explain well. So I browsed some resources online but still do not quite understand it. Please help. Thanks in advance.
|
Other
|
explainlikeimfive
|
{
"a_id": [
"gj4du6l"
],
"text": [
"In computer science and mathematics, we can think of a function as being a \"thing\" in its own right, in the same way that a number or a string of characters are things. A higher-order function, then, is a function that takes *other functions* as inputs. A basic mathematical example is the derivative, where the input is the original function and the output is another function that is the derivative of the input. Other examples include things like iteration, where you might have a function that takes in another function and an argument, then applies the input function *twice* to the argument. In the same way that you can have a function that takes in a number and returns its square, you can have a function that takes in a function and returns some other function."
],
"score": [
10
],
"text_urls": [
[]
]
}
|
[
"url"
] |
[
"url"
] |
kwj6nf
|
what’s the point of using credit cards? Why would you bother borrowing money on such a short term loan?
|
Economics
|
explainlikeimfive
|
{
"a_id": [
"gj4fipy",
"gj4flow",
"gj4i8qd",
"gj4llkv",
"gj4jbks"
],
"text": [
"Well, for one, it builds credit. You're more likely to get approved for loans if you have a record of paying off debt (however small). Also, it's way more secure. It's waaaaaay easier to cancel fraudulent charges on a credit card that get money back removed from your checking account.",
"In the US at least - better security on your account compared to using a debit card tied to a checking account. Also easy reward points that you can use for cash back, reduce costs of items in stores, traveling, gift cards, etc. If you're paying it off every month then you don't accrue any interest so it basically is \"free money\".",
"Another reason is access to a product or service when the actual cash for it isn't immediately available. I get paid twice a month. Unless my toilet breaks down during the correct week, I may not have enough cash on hand (or in the bank) to get it fixed before terrible things happen. Ergo, I put it on a card and pay it when the money is in the bank.",
"Aside from all the other explanations here, where I live (Argentina) with a credit card you can buy stuff and pay in some amount of monthly payments (usually 3, 6 and 12 months). A credit card is pretty much the only option for paying this way (not including bank loans for buying cars or houses), so, if let's say your refrigerator blows up, and you don't have enough money saved to buy one in 1 payment, you can buy it with a CC and pay a fraction every month. In stable economic periods (which unfortunately are rare here) you can even get those monthly payments without interests, meaning you end up paying the same amount when you add all the payments, as you would have payed in cash. But, even if you have to pay interests, sometimes it is still the better option (because the payments are set at the time of purchase, they can't get more expensive, and sometimes the inflation of currency makes the interests negligible) or sometimes that's your only choice, apart from not purchasing your much needed refrigerator, because you don't have all the cash saved.",
"Credit cards came around because transfering money were dificult and time consuming. Carrying around large amounts of money were problamatic, checks were also dificult to use and took time. Especially as a lot of the shopping were done by wives, kids and servants who could not be trusted with handling money as the husbond were busy working to get the money to spend. So shops usually allowed people to buy things on credit. I still remember this in the 90s as you could just walk into the local grocery shop and get whatever food you wanted without paying. Everything was written down by the casheer in a big book and once a month they would send a bill for everything. This made payment much easier as you could send one big check at the end of the month. A lot of shops will still extend similar credit to companies as it could be hard to manage company credit cards for all your employees as well as discounts you have negotiated. It is much easier to tell your employees to go to the shop to pick up the items and then just flash the company ID to the store employees as they ring it up to have it billed directly. The problem with this system was that larger stores could not keep track of all the people shopping there. A lot of the people shopping did not have any sort of ID and it could be hard to keep track of who were authorized to purchase on behalf of who. So the stores started issuing their own ID cards with this information. Then to avoid having to carry multiple ID cards for different stores they grouped together and issued one card that was accepted in all stores. And this soon grew country wide and then world wide. It can be argued if credit cards are still useful. Some countries did jump over credit cards and implemented debit cards first. But these generally require a connection to the bank to verify the transaction. In places where Internet connections are not guaranteed and banks do not always want to work smoothly with each other debit cards are harder to implement."
],
"score": [
30,
7,
4,
3,
3
],
"text_urls": [
[],
[],
[],
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
|
kwjppj
|
Why is our recorded voice different from the voice in our head? Which one is ‚real‘?
|
Technology
|
explainlikeimfive
|
{
"a_id": [
"gj4jf7f",
"gj4jph8"
],
"text": [
"Things you hear in the world are coming into your ears, hitting your eardrums, and interpreted by your brain. When you speak, your ears hear a combination of your voice coming out of your mouth combined with the vibrations of your vocal chords, traveling through the flesh and bones of your neck and skull. That serves to dampen the sound. This makes it sound deeper to your brain than it sounds to other people who are only hearing the sound coming from your mouth. When you hear your recorded voice, you’re getting just the oral audio without the internal vibrations. This is what your voice sounds like to other people.",
"When you hear yourself speak, the sound is partially conducted through your skeleton (skull bones) which pitches it lower. Hearing the sound just with your ears sounds higher pitched than what you are used to. I believe that's why broadcasters and singers wear headphones when recording/broadcasting so they can hear themselves as others do."
],
"score": [
4,
3
],
"text_urls": [
[],
[]
]
}
|
[
"url"
] |
[
"url"
] |
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