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mva8io | What do physicists mean when they say photons do not experience time? They took time to get from A to B, so didn't they experience time in that journey? They had one position at time X and another at time Y, isn't that a different experience? | Physics | explainlikeimfive | {
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"That's a conventional way of understanding time and it works for pretty much everything we encounter in our daily lives but it just an approximation. When we're talking about relativity, the rules change. The speed of light is constant for all observers in all reference frames. Light is always traveling at the speed of light. Since light can never be at rest, it has no valid reference frame, so it's impossible to \"put yourself in perspective of a photon\". That perspective simple doesn't exist, so it's meaningless to say photos can experiences time. Now of course light has a finite speed and we can measure that speed in \\*our\\* reference frame, but you just can't do it from the photon's reference frame because it doesn't and can't have one.",
"As you go faster, your relative times goes slower, and there is a limit to this equation when your speed is equal to the speed of light, where theorically, time is \"stopped\" for you if you move at lightspeed. From your perspective (where you don't go at lightspeed), the photon is to a place A and then to a place B. From the photon perspective, time don't flow, so it's both at place A and B.",
"Check out the Twin ~~experiment~~ paradox. One twin gets on a Spaceship and starts traveling at very high speeds (like 80% the speed of light for example). A couple months go by and he returns to earth, but finds that his brother is a shriveled old man, because from his perspective decades have passed. How and why this happens is a question of general relativity and can definitely not be explained in an ELI5, most certainly not by me. However if you take this to its extreme and travel at the speed of light, time will have slowed down so much you will travel anywhere \"instantaneously\", however only from your perspective. Everyone else will still have to wait 4(?) years for you to get to Alpha Centauri.",
"Time isn’t universal, it’s relative. This is a result of special relativity called time dilation. For example if someone was travelling at close to the speed of light to the closest star around 4 light years away. From Earth we would observe their trip as taking 4 years, but a clock onboard the ship would show less than that, the closer they are to the speed of light (relative to earth) the less time their clock will show for the journey. If you take the limit of this then something travelling at the speed of light will take 0 time to make any journey. That said this is a bit of an abuse of the theory, in reality nothing with mass can travel at the speed of light, and anything that can (photons for example) doesn’t have a valid reference frame in special relativity. Effectively it’s nonsensical to imagine what a photon experiences."
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mvakog | Why are cold beverages usually more refreshing? Can a hot beverage be Refreshing? | Biology | explainlikeimfive | {
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"Because the colder beverage stimulates the nerves on the top of your mouth more than a hot one and causes you to feel it more. A hot beverage can be refreshing too but less than a colder one."
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mvaofi | Why is the society so afraid of the woman's nipples? They can show 90% of their boobs on YouTube wearing bikini as long as they cover up their nipples, but the moment there is a nip slip, it is censored, what's the taboo behind woman's nipples? | Biology | explainlikeimfive | {
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"Society is not afraid of the female nipple, although I think it'd be hilarious if it was. Give people jump scares every time they go to watch porn. Society just believes that it is inappropriate for the female nipple to be on display in certain contexts, like most public environments. Society operates under a set of broadly agreed upon rules designed to make cooperation and interaction with other humans go as smoothly as possible. One of these rules is a general sense of modesty. Clothes aren't strictly necessary, and there have been societies in the past that used clothing differently, but most societies have come to the conclusion that they operate best when people are covering up certain parts of their body, largely from the perspective of minimising visible sexuality. Anything associated with sex society expects to be obscured in most contexts, and that includes boobs. The degree to which they should be obscured can vary though. Right now, the level at which people will think certain outfits are inappropriate is earlier than exposed nipples - walk around with large portions of your breasts exposed and a lot of people will think that's pretty inappropriate. Exposed nipples simply serves as a basic guideline for \"*definitely* too much\". A good way to look at this is through the example of the bikini. Most people think bikinis are fine in the context of beaches, swimming pools and some other holiday-style contexts. Most people also think bikinis would be extremely inappropriate at funerals. The male nipple also has many contexts its seen as inappropriate. The whole thing of \"no shirt, no shoes, no service\" is an example of that. As for where these things come from, it's largely about the fact you're breaking a norm, rather than anything specifically offensive about the thing you're wearing. A bikini is inappropriate at a funeral because the norm is that you wear modest clothes at such an event. Wearing a bikini to one is an implicit statement that you don't respect the deceased person, because it's more important to you to take this opportunity to flout the social norms. If however it became normal to wear a bikini to a funeral, such an act would no longer be seen as disrespectful. So, the female nipple is inappropriate in public largely because not many people actually go topless in public, not many women especially. If suddenly everyone woke up tomorrow and decided to never wear anything above the belt ever again, it'd only be a few weeks before everyone was fine with the female nipple. Just look at nudist colonies. There, it's often seen as ruder to wear clothes than to not wear them, because the norm is to not.",
"I've seen twitch girls showing cleavage and sideboobs all day but the moment a nip slip happens, the ban hammer comes down, like people are allergic to public woman nipples, doesn't compute with me.",
"Really not sure. Women have a right to show nipple in my opinion. I also have the right to stare.",
"I think it is about women's bodies as currency. They carry a price tag (not always monetary). By censoring and moving the point of control to outside the person who owns the body, that person does not own themselves. The agenda and price is determined elsewhere. A fully naked woman (or man, to be honest lol, but in this society we're all like, nakid women go brrrrrrr) is disturbing because women are meant to be naked only for the men who own them or pay for/look at them. Because of that assumption, she's also - according to the world - sexually available . If she's naked on her own terms that's A Problem. Maybe look up google scholar about these taboos, there will be some pretty cool reading I think nipples are more symbolic at the moment, than any other specific reason. In Victorian England it used to be ankles that were the hot item du jour, to the point that people would cover up their *table legs* so as not to make an erotic statement.",
"free the nipple is an equals right movement. It’s still a taboo showing your breasts or going topless to the beach. But a guy can.. It can be inappropriate when it comes to men staring. All types of men already look at your cleavage or seeing you breastfeeding … The very word (let alone the image) goes straight to the minds and loins of men the world, making up all sorts of conflicting thoughts and scintillating fantasies. The VS already has 5 or 6 states supporting being topless in public. And don’t forget that many people are like Barney Stinson. “Boobs?”"
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mvaxig | Why are certain vitamins such as C and E applied to the skin in the form of serums? Why isn't having vitamin C enriched food enough? | Biology | explainlikeimfive | {
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"The body is not uniform in terms of the chemicals found in certain locations. Some bits of the body have more and less of certain things than others. When you consume nutrients, they enter the body through the small intestine and their first stop is the liver. From there, they may be stored or modified, or distributed via the bloodstream to other parts of the body. Consumed vitamins tend to be distributed evenly between cells, because the body can't preferentially send it to some places over others. That's generally fine in most cases because you're just using these vitamins to stay healthy. However, if you want to try and use vitamins to prevent physical signs of aging, then you really want to be maximising the vitamin delivery to the skin. For that, it would be more efficient to apply the vitamin directly to the skin, which for the same amount of vitamin would put a lot more in the skin and comparatively less in other cells. Topical creams are not an appropriate substitute for dietary vitamins, because vitamins are needed for more than just skin health, but there is evidence that extra vitamins in creams can improve skin quality more efficiently than extra vitamins in diet. Having vitamin C-enriched foods is plenty to ensure normal bodily function, but if you're a big pharmaceutical company wouldn't you want to sell an overpriced, unnecessary product to people who care about appearing youthful if the science was just enough on your side to make it not technically false advertising?",
"There's no reason to apply vitamin C to your skin. Vitamin C is acidic and can cause the skin irritation and can thereby temporarily reduce the appearance of wrinkles (but that's temporary).",
"Vitamin A and C do help the skin look youthful but in such high concentrations they cause irritation, burning, stinging and redness. Skin creams and serums with them in in effective concentrations are prescription only. As for Vitamin E it's an anti-oxidant and the science around those is sketchy at best, anti-oxidants in the body help deal with free radicals which can affect DNA and damage cells however they also help fight bacteria and infections. There's no evidence rubbing in or eating anti-oxidants leads to a higher amount within the body. Skin creams in general are generally snake oil, the 3 active components are a moisturiser, a soluble polymer and hydrogen peroxide. The moisturiser moisturises, the soluble polymer will be much like those found in hair gel and firm the skin just like putting sticky tape on your face and the hydrogen peroxide burns the top layer of dead skin off leaving you with that tingling sensation and that warm glowing feeling. Everything else is largely bullshit or in too low a concentration to be effective."
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mvazru | Why is the tongue more efficient than the fingers in spotting where the food is stuck between my teeth? | Biology | explainlikeimfive | {
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"Any answer saying the tongue is more sensitive is wrong. It's definitely not about sensitivity. The fingers are super sensitive and can pick up differences, textures, stretch, general form factor a fraction of a millimeter and even less. The tongue cannot. It boils down to \"maps.\" Your brain has a map of everything around you which it references as you move or interact with the thing. Some things are better represented visually (e.g. the map of a room is more eyesight based whereas for an instrument the map might be more touch and sound based). Your tongue has a better touch-based representation map of your mouth than your fingers do. The brain knows, based on the very same sensation of food, what muscles to contract to reach that food using a tongue, but not so much how to do so with fingers. **Edit:** The tongue might be slightly better at certain forms of touch but altogether the fingers are way, way, way, way, way better tuned for all sorts of touch.",
"There are waaaay more nerves on the tongue. Even though the tongue feels big in your mouth, it's tip is much smaller than your finger. The tongue is far more sensitive and much more flexible. Because of those differences, not only can it can squeeze more deeply into the cracks between your teeth, it can interpret that sensation more accurately. In other words, the tongue is better at finding food between the teeth because that's exactly what it was made to do.",
"I'm sure all the science about nerve endings is the real reason, but I've always thought about it like that's where your tongue lives and it's the difference between finding something in your own home, versus trying to find something in your neighbors home.",
"The tongue and mouth in general have way more nerve endings per unit surface area than your hands. To prove this: 1. take two toothpicks (or any other thin pointy object you can put in your mouth.) 2. Now, hold the two toothpicks so that their points are less than half a centimeter apart. 3. Without looking at your fingers, lightly poke your fingertip with these two points. 4. Can you tell that you poked yourself with two points? Probably not, and if you did, it was a bit vague and unclear. 5. Now poke your tongue in the same way. 6. You can definitely feel the two distinct points touching you, unlike your finger. You can do the same experiment on your lip and palm. It's the same reason which nicking your finger slightly is just a mild annoyance, but a nick in your mouth can make it excruciating to eat.",
"Same reason your finger can pick up a quarter off the ground better than your tongue. They are purpose designed appendages. Couple that with muscle memory and you got a pretty good location finder.",
"I'd guess it's because your tongue lives in your mouth, and your fingers live on your hand. So naturally, being a resident of your mouth, the tongue is \"at home\" in your mouth and has somewhat of a home field advantage. That to me would be the reason why your tongue is more or less a seal team 6 when you deploy it in your mouth to find bits and pieces of food that are mia/kia in the whole war your mouth has declared on food it comes into contact with. Albeit a weird analogy, it fits for this particular combat engagement and of course, has somewhat of a home field advantage. And that being said, no soldier gets left behind.. so the tongue is sent on the recovery mission to find any stragglers left on the battlefield and almost always completes the mission. Sometimes you gotta call in a support team from the 101st toothpick battalion.. and if they have a hard time then they call in their heavy support team of the 32nd which are currently using the mint \"flossers\" direct attack munition that is ~~laser~~ hand guided directly onto the few remaining insurgents dug in deep in the molar region of the battlefield. But, the seal strike team, along with their advanced weaponry provided by those strike teams seem to always get the job done.",
"Your tongue lives in your mouth, it knows where everything belongs. It also notices things that are out of place, like you in your room. And, just like when your friends visit, your fingers are also only visitors, so they are not as familiar with the surroundings as someone that lives there.",
"Point of reference. The only thing a certain part of your tongue usually touches is a certain part of your teeth. Whereas your hands need to touch anything and everything. If your hand spent all of it’s time since birth inside of a baseball mitt, what the inside of that glove feels like would basically be burned into your brain. If a pea fell into the glove it’s be the only feeling different to your glove your hand ever felt, you’d be super aware or where that pea was. It’s why your mouth feels so bizarre after getting a tooth removed or after getting a gap you’ve had for a long time bridged."
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mvcnp6 | what is the space time continuum | Physics | explainlikeimfive | {
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"Imagine a typical XY graph - a line going up and down for the Y axis, and a line going across for the X axis, the usual. Any time you make a dot on that graph, the dot has both an X location and a Y location, right? Even if a dot is right on the X line, it still has a Y location; that just happens to be Y = 0. That means that we can call the *entire* graph the \"X-Y Continuum\". Any point that exists on that graph, no matter where, is \"experiencing\" both the X axis *and* the Y axis - the two axes are basically just different parts of an address but it's all a single continuous graph. Same thing: if we're sticking with the XY graph analogy, then everything in the universe has positions on both a \"space\" axis and a \"time\" axis, and the universe is the single continuous graph - the \"space-time continuum\"."
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mvdgdm | How does the brain work differently for people who enjoy the sensation of pain? | Biology | explainlikeimfive | {
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"Aa far as I know, masochism isn't considered a neurodivergence, so probably no difference. When you feel some types of pain, your brain liberates endorphin as an anesthetic, and that can cause pleasure. But that isn't exactly masochism, though it's part of the experience for masochists. Putting it simply, masochists like pain. They don't feel pain differently, they just like the feeling of pain itself, same as some people just can't stand spicy food, while others like in a certain moderation, and a few are crazy for it. Edit: typo",
"In the body, there isn't any difference between arousal (fear) and arousal (sexual). It's just your body getting ready to do *something*. How we experience it depends on how we interpret the context. So in a context that isn't dangerous, pain still causes arousal which can get interpreted as something other than fear. So no, the brain doesn't work differently, just how you think about it does."
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mve0ec | / Why our mouth turns downwards when we're talking and on the brink of crying? | Self explanatory title but why is it that when we are talking and on the brink of crying, or in a stage of heightened emotion, that our mouths turn downwards in the stereotypical :( I understand that it's facial muscles but what triggers that response? What chemicals/brain messages/ etc causes that? | Biology | explainlikeimfive | {
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"Facial expressions have one purpose: communication. Turns out early humanoids survived better when they were able to tell how their friends were feeling. Over millennia, it’s been engrained into our brains that when we feel sad, we may get more help if we show our sadness. It just so happens that we ended up using smiling for happiness and a downward mouth for sadness, some monkey species have it completely opposite and a smile could be a sign of aggression for example."
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mve38u | why do some apps give you gift cards just for scanning receipts? | I know there are different apps or websites that give you “points” for just scanning your receipts from other stores, and you can redeem points for different rewards like gift cards. What is the website gaining from this? It always seems too good to be true because I don’t know how they’re making a profit. | Technology | explainlikeimfive | {
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"A good rule of thumb is that if a company is giving you a free product, you are the product. They're getting information on what someone of your profile (age, gender, income, background, location) tends to purchase. Compiled with everyone else doing it, they can sell that kind of information to companies interested in creating more targeted ads to the demographic they're interested in.",
"They Gain lots of knowledge about your habits. What you shop, where you shop, when you shop. With that info they can build a profile about you. They can deduce if you have a family, likely ages of kids etc etc. They can then sell that data so that “appropriate” ads can be directed your way.",
"Besides, gift cards are not very expensive - especially when you have so much and detailed information about your customer that you can share Basically, they go see the vendors offering gift cards and say: \"What kind of new customers are looking for? I can select them based on if they purchasing habits and send them your gift cards\"."
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mve4gd | How do phones keep track off time while off and without internet connection? | Technology | explainlikeimfive | {
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"Even when your phone is off, there is still a very small circuit that is powered. This circuit, among other critical things, is keeping track of the current time. It consumes very little power, so it doesn't drain the battery. Even when the battery says it's dead, there's enough charge left to maintain these low power critical functions. Every computer device that keeps time will have a battery somewhere to help it keep time when its main power is gone. Even a desktop computer will have a watch-style battery on the motherboard to keep the circuit going. One extra advantage that cell phones have is that, if they ever happen to go completely dead, they can set their time back via GPS. The way GPS works, satellites in known positions are broadcasting a signal that contains their time. If you get 3 pings and know the current time, you can figure out your relationship to those 3 satellites and it narrows it down to one point. If you can get pings from 4 satellites though, you can actually narrow down your position *and* the time from them. This is why phones have such accurate timekeeping.",
"There is a type of chip called a Real Time Clock which is specifically designed to use as little power as possible to keep track of time. It is usually connected to a tiny battery or even just a capacitor so that it can keep track of time even when the device is powered off and the main battery is out of power or disconnected. It can also be programmed to send a signal to the device to power on or at least wake up from deep sleep at certain times."
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mve4qy | how do Alzheimer's and dementia drugs help? What do they do in a patient's "head"? | Biology | explainlikeimfive | {
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"Neurotransmitters are released from neurons to stimulate the next neuron. Afterwards the neurotransmitter is broken down by an enzyme. In Alzheimer's they have limited function of neurons and not enough of the neurotransmitter to trigger the next. The drugs inhibit the enzyme that breaks down that neurotransmitter, this allows a concentration of the neurotransmitter to help the neurons \"fire\" thus stimulating better function.",
"Brain needs chemicals to work properly. You may have heard of some like dopamine or serotonin. Treatment is based around making sure we have the right levels of these chemicals, either by adding more or blocking excess chemicals. Some treatments work by mimicking them Incase the chemicals our brain produces don’t work normally.",
"It's debatable if they really do work. I recall that it's either hit or miss : SOme people see clear improvement of the symptoms (but the progression is still the same) and some absolutely no effect at all. The drugs for treating alzheimer's symptoms are increasing acetylcholin, which is a neurotransmitter, a molecule that allows communication between neurons, it was shown that it was kind of lacking in Alzheimer's disease patient and depending on the brain area, acetylcholine is involved in memory and attention. So increasing acetylcholine could help potentially."
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mvf1fc | the separation between the conscious and "unconscious" mind | Biology | explainlikeimfive | {
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"Well hey! I’m not a psychologist myself, but I don’t agree with your psychologist! Of course there’s a subconscious mind handling all of your daily processes like breathing and digesting like you said, but if you look a little deeper in there’s a LOT of things in your head that you can’t control! Beyond fears common to most humans and dictated by evolution, you can’t consciously control your phobias. You can’t consciously control your taste in food or people! You can’t consciously decide your own sexual orientation! And I hate to pull out the vague-card, but I sure as heck can’t consciously decide what to dream at night (And my dreams are just so weird man). Also, once you get very good at skills, you can start to do them without even thinking. If ’you’ aren’t thinking about these things, what part of your brain is? Once you start thinking about all the things your subconscious mind does, you might even end up in ‘do we even have free will at all’ kinds of territory. Well, pulling back, did your psychologist specifically say ‘subconscious thoughts’, as more in relation to intrusive thoughts? Because those do also exist for a lot of people, and are bad thoughts that they would really not be having. And what about people with mental illnesses like schizophrenia, or even depression? They can’t consciously control their feelings or thoughts even more than the rest of us! I generally like to think of the brain as this vast and complex machine that does stuff and processes things and is always working, and consciousness itself is more of an emergent property of all of those things working together. So I would disagree with your psychologist and claim that the brain is MOSTLY subconscious!"
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mvf9a1 | Why are "stop" buttons (on TV remotes, DVD players, etc.) typically red squares if stop signs are red octagons? | Other | explainlikeimfive | {
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"Simple answer: There is no relation between the two. Just because one shape means stop on the road, doesn’t mean stop in an entirely different category should be the same. For the same reason, the play button doesn’t have to be a green light. History of the two have no crossover.",
"They have nothing to do with each other. The development of the traffic signs is actually quite interesting and the shape of the stop sign was chosen because this was a very distinct shape that was easy to spot even if the sign itself was dirty. The stop button for A/V equipment was coincidentally developed around the same time but in a completely different way. At that time most equipment used tape which could move in both directions. So the play button and especially the fast forward buttons needed an arrow to indicate direction. The stop button however had to be symmetric and in a similar style to the other buttons. So the square was chosen to indicate stop and the other simple shape, the circle was chosen to indicate record.",
"The play/pause/stop symbols appearing on modern media players come from the ones originally invented for tape recorders. They were meant to be understood by anyone without any language barrier and simple easily recognizable shapes. Usually it was the record button that was red though with all other being black or whatever color stood out against the material they were on. Red stands out though and may be used for stop buttons for all sorts of machinery when you want to make it easy for someone to shut things down. Octagonal stop signs had been around for a few decades before that, but they became fixed in their current shape and color in the Vienna Convention in the 60s. They are unrelated to one another. One telling you to stop and another being you telling a device to stop what it is doing. That both may come in red is just a function of red being highly visible and used to make things stand out."
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mvgc2t | Why do we like listening to sad music when we're sad? | Other | explainlikeimfive | {
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"Oddly enough, the Pixar movie \"Inside Out\" explains it pretty well I think. It's ok to BE sad. Sometimes in order to cope with the situation and move on from it, the emotions just need to be embraced rather than ignored. Embracing those emotions sometimes means bawling for an hour listening to sad songs.",
"maybe taking solace in the fact that others have felt this way before? that it's okay to be sad, and to embrace the emotion fully, and to feel connected to others? sadness is a very lonely emotion, especially when it's not due to some kind of universal event"
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mvgcbl | In the house, why does heat set at 68 feel different than ac set on 68? It’s the same temperature but they feel very different! | Other | explainlikeimfive | {
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"Others have mentioned humidity which can definitely make a difference. Another big difference is from radiant heat. On a hot day, the heat not only warms up the air, but also the walls of your home as well, and those walls radiate heat back inside. Your body absorbs radiant heat much more readily, thus why you can feel warm by a campfire on a cold evening. Your standard thermostat can't accurately account for radiant heat, so even though the air temperature may be the same, you'll feel warmer on hot days as the walls warm you up.",
"There's something called relative humidity. Air can hold a certain amount of dissolved water. The capacity of the air to hold that water changes with the temperature of the air, with hotter air holding more water than colder air. If you're heating up air from the outside, it doesn't add any humidity to it. While it contains the same amount of water, the relative amount is lower. Because the relative amount is lower, the air actually tries to evaporate moisture out of your skin, since it can hold it better than your skin can. This makes a heated room feel dry. If you're cooling down air from the outside, it might actually be holding into more moisture than it can at room temperature. As you cool it down, it actually loses ability to hold water, so it condenses down. This means the air coming out is actually very moist.",
"It's probably several differences reasons and I can think of three. 1. Humidity plays a big part in how the air feels. If you're heating to 68 then it's likely winter time and humidity is low. If you're cooling to 68 then it's summer and humidity is high (though the AC does pull water from the air, it could very well still be wetter than winter air. 2. Depending on the current season, 68 can feel cold or warm because you're more accustom to the current outside temp. In the winter, 68 feels warm compared to the outside temperature and you're likely wearing more clothes. In the summer, 68 may feel a bit chilly because it's hot outside and you're likely wearing less clothes. 3. It's 68 according to the thermostat which is only capable of reading the temperature of the air that directly surrounds it, meaning the actual average temperate of the room could be higher or lower. Let's say it's winter and you're heating to 68. The vent that supplies the heat is on the opposite side of the room as the thermostat. The heat will kick on until the thermostat reads 68, but the air outside the vent could reach a temperature much higher than that before the air around the thermostat heats up. This means the average temperature of the room would be a little higher than 68. The opposite would happen in the summer, where the air around the vent would become much colder before the air around the thermostat hit 68, meaning the room would be colder on average. In other words, your thermostat says it's 68 in both cases, but it's likely a bit hotter when heating and bit colder when cooling.",
"The temp you set is the goal temp to get the air to. You don't get 68 degrees by generating 68 degree air. For heat, you blast 100 degree air to mix with the existing ambient air until they mix to reach 68 degrees and then the furnace shuts off. And when you want to cool a room to 68 degrees, the AC blasts 40 degree air which mixes with the air in the room until the combined temp is 68 and then the AC shuts down. But there will be hot or cold spots in the room, especially in proximity to your vents, so you may feel more of the cold AC air or hot furnace air in spots until it mixes adequately.",
"Worked in AC business for 16 years, the difference is based on where your thermostat is compared to where you are \"feeling\" the temperature difference. When your AC turns on there are only two things that change on most modern AC units. 1: the compressor or the heating element is on or off 2: fan speed (even this is for units less than 10 years old) When your Air conditioner is told by the thermostat \"it's cold, we need heat\" it turns the heating to on and the fan to on. No matter what that heat is at 100% and it's forcing air through the duct to the different rooms. So if you are in your bedroom with the heat on it is actually a bit hotter than if you were standing next to the thermostat because heat takes some time to travel and the thermostat takes time to recognize its at the correct temp. And for cooling the opposite happens, cooler Temps further from t-stat. Also as mentioned before the humidity is a factor as well. Heating a house does not remove humidity while cooling does. Edit to add: this is how most residential AC systems work, there are some that are smarter and have a few more bells and whistles that try to even it out but usually come with a premium cost and maintenance so I didn't delve into those systems. At the heart of those systems the above still applies generally. If your interested in some of those let me know and I'll delve deeper."
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mvgret | What is "sexual communal strength" in this quote "people high in sexual communal strength – those who are motivated to be non‐contingently responsive to their partners' sexual needs – are able to sustain higher sexual desire over the course of time and navigate sexual disagreements" | Here is the abstract. URL_0 | Other | explainlikeimfive | {
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"It means empathy. Understanding what is required by another to experience pleasure and taking pleasure in providing that without expectation of a return."
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mvhdre | Why is cow meat red and bloody and chicken meat is not bloody? Does the chicken muscles not have blood? | Biology | explainlikeimfive | {
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"That’s not blood coming out of the beef. It’s myoglobin, helps deliver oxygen to the muscles. nearly all the blood is drained before it’s packaged, and since meat is about 70% water... it’s pretty much just “meat juice” Also, store bought poultry are raised in tight confined areas, so the chickens muscles don’t get much use. Most commercial poultry are Cornish crosses, who finish out in just eight weeks. Beef on the other hand, are usually around 9 months to maybe a year depending on how efficiently they can put on weight. Much more time for the muscles to be active and need more oxygen.",
"As others have said, there isn't blood in any properly butchered meat product. The thing that makes \"red meat\", like cow or ostrich, different from \"white meat\", like chicken or pork, is not the presence of blood or the type of animal. Chickens and ostrich are both birds and cows and pigs are both mammals and all of them have blood. The \"red meat\" effect is a compound called heme. This is a common organic compound, even some plants produce it. Lots of heme = red meat; less heme = white meat. The vegetable meat substitute people use plant heme to make \"impossible\" fake ground beef."
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mvhp2g | What happens to muscles when they are stretched regularly? | What's the difference between a flexible person's and an inflexible person's muscles? Why can't a person just do the splits? Can someone stretch too much in a day like lifting or running? | Biology | explainlikeimfive | {
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"The body has a protective response called the stretch reflex. When you stretch a muscle rapidly, the muscle sends input to your brain, the brain sends a response back to shorten the muscle in an attempt to protect that muscle from being overstretched. This contraction while the muscle being stretched is what can cause injury. When you stretch regularly in a controlled manner, you don't trigger this reflex which allows you to extend the muscle further than normal. This allows the muscle to remain relaxed and temporarily lengthens the muscle. To my knowledge the primary difference between flexibility and lack of is the suppression of the stretch reflex. A flexible person doesn't literally have longer muscles at rest, but their body is more adapted to relaxing muscles and allowing them to temporarily lengthen beyond their normal length. Without practicing flexibility it's difficult to overcome the reflex and your body is less able to relax as heavily. This is why you don't static stretch *before* a workout - that relaxation and temporary lengthening actually makes it more difficult to generate power so your performance *is* worse than if you didn't stretch. Dynamic stretching has a different purpose though - to bring blood to the muscles used for the pending workout. Not sure if there is \"too much\" stretching possible in a day, assuming you aren't intentionally forcing stretches or anything."
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mvhumv | How do rats digest solid stuff like plastic, sponges ? | Biology | explainlikeimfive | {
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"They generally don't, they either pass it as is, or it gets stuck and builds up into an obstruction and kills them",
"if you're seeing a rat chew through plastic, they likely didn't swallow it, they just chewed it."
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mvij55 | How did the word 'right' come to mean both a direction and 'correct'? | Other | explainlikeimfive | {
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"The original meaning of “right” was “correct” or “straight” or “true” - as in a “right triangle” or “right answer.” Around the 12th century, the term started to be used for the hand that was stronger for most people. The interpretation was that this was the “correct” hand for writing or doing tasks.",
"You might be interested to know that the word \"sinister\" comes from the word for \"left\": URL_0 Right-handed people are more common. Left handed people were looked down upon."
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mviomy | Is it possible to disprove the laws of physics | This is something I've been wondering about for some time. Is it possible that some laws of physics are straight-up wrong, and can be disproved as our understanding/technology improves? How concrete are the laws of physics? Is it possible for us to be absolutely certain about anything? | Physics | explainlikeimfive | {
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"Scientifically, it is possible to prove any of these things...Well, maybe not *wrong*, persay, but *inaccurate*. Basically the whole process for scientific discovery goes like this: Scientist 1: Hey, so I did X,Y,and Z, and [result] happened! Other scientists: Lemme try! Hey I did the same things, and [result] happened too! You're right! This is how our understanding works. But then this guy can come along... Grumpy Scientist: Yea, well, you did X,Y, and Z, and got [result], but if you do A,B,C *and* X,Y,Z, you get [more specific result], which gives us a better understanding of [result]. Other scientists: Holy crap he's right! So science just builds on what we know, have observed, and it will inevitably shift around *a little*, but proving things like the basic laws of physics just flat *wrong* is highly unlikely.",
"Being disprovable is a fundamental basis of all science. All scientific laws must be disprovable, because that's how science improves. Science loves being proven wrong, because that means that we've figured out something new and we've improved our knowledge.",
"Yes. \"Laws of Physics\" could also be known as \"Good Theories That Haven't Been Disproven. Yet.\" Or \"What Happens Every Time, So Far\".",
"As a general rule, nothing is 100% completely rock solid certain in science, or at least it's not treated that way. Scientific laws are not immutable- they're just extensively, rigorously proven methods of defining natural phenomena of the universe. In other words, scientific laws are a way of bringing the fundamental properties of our universe down to human scale. However, *disproving* a scientific law entirely would be monumentally unlikely, given the extremely rigorous methods that go into formulating them. It's also not what science aims to do. However, it's possible that tomorrow someone makes a new earth-shattering discovery that proves an existing law *incomplete* and forces us to reevaluate/reformulate it to accommodate this new knowledge- and there are many brilliant humans around the world going to work each day trying to do just that.",
"That's kind of the point if science. It is to have an idea something is wrong and use the scientific method to prove it. But if your wrong that's also good as it helps to further prove something else.",
"Technically this pretty much has to happen at some point, because we have two major theories at the moment describing how the universe works--quantum theory at very small scales, and relativity theory at large scales. The problem is, those theories contradict each other in some details, so they both can't be 100% correct. At some point someone will figure out a theory that works at both large and small scales consistently, the so-called \"Grand Unified Theory\", and something in that is going to disprove something in one of those big theories, it pretty much has to.",
"Let's say you decided you wanted to know what colors of cars existed in the world. Every day, you wake up bright and early at 7am and start watching the road in front of your house. You keep a tally of all the different colored cars you see. All day you watch, until you go to sleep at 10pm. You saw tons of cars - some blue, some silver, and some black. But never a red car. You theorize that there are only blue, silver, and black cars that exist. Every day you continue your observations and they are confirmed. Only blue, silver, and black cars. One day you happen to wake up early - 6am - and look out your window to see a red car driving by! Holy shit! A red car! You'd never seen a red car before. You thought they didn't exist! It turns out the neighbor up the road that drives a red car has to be at work by 630, and so you never saw him drive by in your previous experiments. Now you update your theory to include the existence of red cars. You tell your friend about your theory and he looks at you like you're crazy because he's been doing the exact same experiment from his house and he only ever sees red and yellow cars! Now you both have to update your model of the world to include this difference - there exist red, yellow, blue, silver, and black cars, but there are some special rules about when and where they can be seen. That's how science works. You make a theory based on available evidence, then you find new places to look to see if your theory is still accurate. If not, you update your theory, and repeat the process! We've been looking at some things in physics long enough that its unlikely that we find a new, every day situation where, like, gravity ceases to exist. But if we look in rarer and weirder situations like inside a black hole or in the nanoseconds following a particle collision or something, we may find exceptions for some of the physical laws we know.",
"Yes - it is absolutely possible to prove something held as a scientific law to be wrong. Today's scientific laws are the product of doing exactly that for thousands of years. Back in the 4th century BC, the Greek philosopher Aristotle stated that falling objects accelerated at a rate directionally proportional to their weight. He \"proved\" this assertion by using a thought experiment - the idea of dropping a cannonball and a feather from the top of a tower. Everyone knew how differently feathers and cannonballs fell, so his statement went unchallenged for hundreds of years, and everyone just accepted it to be true. In the 6th century AD, the Egyptian philsopher Philoponus put this thought experiment to the test, but instead of using a feather and a cannonball, he used two dense weights, one twice as heavy as the other. If Aristotle's assertion was correct, the lighter of two would take twice as long to hit the ground. When he actually did the experiment, the two weights hit the ground at almost the same time - the lighter one did take longer, but only slightly. Philoponus later made a quite profound comment in regards to his disproving Aristotle: > Our view may be completely corroborated by actual observation more effectively than by any sort of verbal argument And that's pretty much how science has worked ever since - it's not enough to simply have an idea that makes sense, you have to be able to prove it experimentally.",
"\"Laws\" and \"Theories\" in science are written in such a way that they are [Falsifiable]( URL_0 ) which means that it would be possible to prove them wrong There are statements that are impossible to prove wrong like if I were to claim that there were an invisible teapot in orbit around Mars that is completely invisible to all detection methods ever, you have no way to even approach that to disprove it, the statement itself is impossible to prove false, it is \"unfalsifiable\" But laws and theories in science and math come with hard rules that you could prove don't actually align with reality. If you show up with good data showing that gravity *actually* falls off with Radius^2.005 and not Radius^2 then you will have proved Newton's Law of Universal Gravitation to be incorrect. There'll be a lot of push back and people will rerun your experiment to double check but if it holds up we'd go through and update the equation in every textbook. In general we try not to call something a \"Law\" unless it has sooooo much existing experimental evidence behind it that its exceptionally unlikely to be far off of reality There are also a lot of poorly represented theories in science that may be competing to be the leading theory with one ahead at any given time and that leads to a lot of public confusion, but providing the particle theory of light wrong didn't mean that the physics was straight up wrong, just that our modeling of it needed adjustment because light sometimes does act like a particle."
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mviwfs | Why are we doing things like converting to paper straws and trying to invent new plastics when we have hemp, an extremely fast growing, biodegradable resource that can be used to make plastic, paper, cloth, etc.? | Other | explainlikeimfive | {
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"Because hemp is stigmatized due to being in the same family as marijuana. There is no other real reason, hemp has many uses but they’re not realized or used en masse due to it’s relation to a drug. With that being said, as marijuana is being legalized and destigmatized we’ll be seeing more hemp-based plastics, paper, cloth, etc.",
"Hemp is related to weed and we all know weed will cause the downfall of society. So the cotton and logging lobbyists push to keep hemp growing illegal. Even though hemp contains almost no THC, it’s still illegal under the blanket statement of “cultivating cannabis is illegal”.",
"Hemp is one of the sources of fiber material we are using to replace plastic. However it is not the only one. Trees produce way more fiber for the same effort and is therefore much cheaper. We also have a lot of infrastructure to produce cotton, bamboo, and other natural fibers in addition to hemp. We are even able to make fiber polymers from monomers like sugar which is how we make fibers from corn syrup. All of these types of fibers does have different properties and might require different steps in processing to get the right properties you want. So instead of limiting ourself to only one source of material we do use any number of materials depending on which is cheapest and easiest to work with for our purpose."
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mvjcmk | Why are there tensions between Ukraine and Russia? | Other | explainlikeimfive | {
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"There's a lot of history there, but the immediate tensions are because Russia has an abnormally large number of troops stationed on the Ukraine border and Russia has previously demonstrated their willingness to unilaterally invade and take over Ukranian territory (Russia is still occupying Crimea, part of the Ukraine, and has been since 2014). So it's not at all beyond reasonableness that Russia would, again, push into Ukraine and take more territory, and they appear to be preparing to do just that. However, the domestic situation in Russia is also very complicated right now and Putin has a record of using small foreign conflicts to distract from domestic issues, so this might all be posturing. Ukraine is, by far, the largest of the Russia client states from days of the Soviet Union, possesses a huge industrial and resource base in their own right, and has been increasingly aligning with \"The West\"/the EU since the USSR broke apart. Russia views this is a threat to their regional dominance, a source of considerable value while their domestic economy is faltering, and a loss of their traditional buffer between Europe and Russia.",
"Because Russia's #1 geopolitical goal is to maintain it's sphere of influence against The West and the U.S., and Kyiv tends to lean toward the West. However there are still thousands of people, largely East of Kyiv (the Separatists) who still identify primarily as Russian and Moscow uses them as justification to return this territory to Russian control, but really it all goes back to maintaining as much foothold as possible against Western powers.",
"All nations perceive threats around them, based on history and geography. Russia perceives powers within Europe to be a threat to them, as evidenced by the fact that almost all invasions of Russia that have been an existential threat have come from Europe (the one outlier being the Golden Horde of the mid 13th century, which came from Mongolia). Part of the way Russia feels \"safer\" from potential threats from Europe is by establishing a buffer between itself and Europe. Ukraine is, historically, part of this buffer, across multiple conflicts between Russia and powers in Europe. More importantly, Ukraine is essentially the \"final\" buffer, as any opponent that can cross the Dnieper River will be easily able to invade Russia's industrial heartland (particularly in the modern era with mechanized warfare). After the end of the Cold War, Ukraine has been gradually gravitating towards the EU for various reasons (primarily economic). This has gradually made Russia more and more unsettled, and as a result they've been trying more and more desperately to keep Ukraine (or at least, the parts of Ukraine east of the Dnieper) on their side and in their orbit. In 2014, Ukraine experienced a revolution that pushed it much further towards the EU and away from Russia. In response, pro-Russian separatists, backed by Russia, rebelled in East Ukraine and sought to basically align with Russia, leading to the breakaway Donbass region in East Ukraine, as well as the annexation of Crimea by Russia. This all very nearly led to more direct conflict between NATO and Russia, but Obama and Putin effectively froze the conflict, with the US responding to Russian belligerence with sanctions, but not really anything more than that. In return, Putin did not push further into Ukraine, which in turn could have led to a direct threat to US allies and NATO nations Poland and Romania. Now, however, that conflict appears to be thawing out, and it's difficult to tell whether the current buildup of Russian troops is a precursor to an invasion of some (or all) of Ukraine, or simply a means to test Western resolve against the *potential* for an invasion of Ukraine."
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mvjs6n | what is "polycentric law"? | Other | explainlikeimfive | {
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"So, if a crime happens in your town, the police come and investigate, and if a criminal is caught they get tried in the local court house by a judge, using the laws of your society. There is one police force, one judicial system, and one set of laws governing what is and isn't a crime. There is a monopoly on law, basically. In a community with a polycentric legal system you could have multiple entities that are responsible for all of that. Historically this existed with things like guilds or the church, which could have their own system of courts and laws which could impose justice. If a business was wronged by another business of the same type, they could go complain to the city watch (who might not care) or they could take the matter to the guilds, which might give a more favorable judgement or have specific laws to deal with the crime that is more applicable. There is basically an overlap of jurisdictions (the regular city watch and the guild) and two separate sets of laws being imposed (the regular laws of the land and the guild laws)."
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mvkl58 | Is it possible to explain and give an example of EBITDA for a 5 year old? | Economics | explainlikeimfive | {
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"Companies make money (\"earnings\") by getting paid to do stuff. They also have costs...they have to pay employees, taxes, buy equipment, pay rent, etc. As long as your money in is bigger than your costs, you're making money. But...some of the costs are things you can control and some aren't. You can't control taxes. You also can't really control accounting rules, which is how companies keep track of all the different costs are spread out over time and the stuff they own. EBITDA takes out all the stuff that you don't really control to give you a better measure of how much business the company is really doing and how \"healthy\" it is, which can be a lot different than what the accountants say."
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mvlp13 | How can people live off off just one food source? Wouldn’t that have some adverse side effects? | Biology | explainlikeimfive | {
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"Depends how nutritionally diverse the one food source is. Some, typically called \"superfoods\" contain a wide range of nutrients that allow them to cover a lot of bases. Others are so nutritionally poor that all they're really providing is calories. It also depends on the nutrients missing. Some deficiencies manifest much faster than others. Compare for example vitamin C deficiency, which is scurvy, to vitamin D deficiency, which is fragile bones (something you can go never knowing you have if you just never happen to fall down the stairs). Another thing to consider is that we're all living with a bunch of adverse side effects of being alive already. Just because you experience them doesn't mean you necessarily realise that's what you're experiencing or how to fix it.",
"Adverse side effects, like death and being really sick and in bad health is a major issue. We don't see this much in modern times in developed countries, but in human history (and even in poor areas now) malnutrition is a major issue. Living off a single food source, or food sources poor in necessary vitamins or such can cause massive issues and death, we're built to get a lot of stuff in our diet and need it to survive. If you're not able to get a proper diet, things aren't gonna go well over time. You could live off a single source, if that contained everything you need. There are many \"meal replacement\" products on the market that you can live off fine, and people do (its basically a drink packed with vitamins).",
"Yes but depending on what the food is they are eating will depend on how quickly they experience side effects. If you live exclusively on McDonald’s hamburger patties, you’ll see side effects sooner than if you live on Boost meal replacement shakes.",
"Well, in most cases today anyone living off of a single source is either using a diet that was honed over the last few thousand years (think monks) or is using a diet that was designed with modern knowledge and would be less harmful, or includes supplements"
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mvlp6o | Why do sunsets and sunrises look so different? Isn't it technically the same thing? | Earth Science | explainlikeimfive | {
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"Keeping it truly ELI5: the air is typically warmer in the evening than it is in the morning, which can affect how moisture and dust are suspended in the air, which affects what we see.",
"I want to add to some of these answers as a gas phase chemist: The composition of the atmosphere at each level is different in the evening vs. the morning. The sun having been out all day drives a ton of complex chemical reactions in the atmosphere - so by the time the sun sets, there's an entirely different mixture of chemicals in the air than when it comes up. That's not the whole story but it does cause some of the differences.",
"Keep in mind that one is constantly getting brighter and the other is constantly growing dimmer/softer. It’s subtle but it’s there and is noticeable (hence the reason we watch in the first place). This is in addition to what is mentioned about particles and humidity. That’s also why it’s harder to tell the difference in photos as opposed to experiencing it in real life or seeing it on film.",
"One difference is that a lot of smog and water vapor builds up in the sky during the day, between car exhaust, other pollution, water evaporating from day's sun and heat... the refraction of light off all these particles in the sky is what causes the vibrant colors. The cooler air and lack of modern activity during the night means less of that stuff in the sky at sunrise.",
"DO they look different? I've never noticed any difference. What exactly looks different about them?",
"Here's [an article on that exact subject]( URL_0 ). The key excerpt is the following: > All \"twilight phenomena\" are symmetric on opposite sides of midnight, and occur in reverse order between sunset and sunrise, the authors note in \"Color and Light in Nature\" (Cambridge University Press, 2001). That means there's no inherent, natural cause of a major optical difference between them. In short, in the absence of other factors (increased pollution through the day, etc) there is no real natural difference, but there may be a difference is in the observer's awareness of the time of day and your body's physiological response as well. For example, your eyes may be more sensitive in the morning due to being dark adapted, so your perception may be a bit different than it is in the evening. The one thing that *is* different between sunrise and sunset is the angle at which the sun leaves/approaches the horizon: > According to the astrophysicist Neil Degrasse Tyson, director of the Hayden Planetarium in New York, there's also a trick for distinguishing a sunrise from a sunset played in reverse. Because of Earth's tilt, the sun doesn't rise or set along a vertical line, but at an angle. \"When viewed from all latitudes north of the Tropic of Cancer (23.5 degrees north latitude), the sun always rises at an angle up and to the right, and sets and an angle down and to the right,\" Tyson writes on his website. \"That's how you can spot a faked sunrise in a movie: it moves up and to the left. Filmmakers are not typically awake in the morning hours to film an actual sunrise, so they film a sunset instead, and then time-reverse it, thinking nobody will notice.\"",
"They might look less different than you think - sometimes one will be used for the other during filming!",
"The ELI5 version: your eyes see differently depending on whether it's getting brighter or darker. Longer version: During the day your eyes are light-adjusted, and you're primarily seeing the world through color-sensitive cones. As the sun sets and the world gets darker, your eyes don't shift to night mode as fast as the light level changes. So your eyes remain sensitive to color, with an emphasis on reds, greens, and blues; but it gets perceptibly darker faster, and due to the [Purkinje Shift]( URL_0 ), as your eyes adjust to darkness the blues and purples stand out more. During the night your eyes have had time to get dark-adjusted. You're primarily seeing the world through mostly monochromatic rods that are 1000x more light sensitive than the cones. You see the sunset coming way ahead of the sun actually cresting the horizon, but because of the Purkinje Effect you see the blues of the sky most prominently. As sunrise approaches your rods pick out subtle changes in light easily, but are largely insensitive to changes in color. Those changes in color happen after the sun crests the horizon as your eyes start to become light adjusted. But at this point the Purkinje Shift is happening in reverse, so as your eyes get light adjusted they pick out the pinks and reds and oranges mostly prominently, and the blues and purples seem muted in comparison to sunset.",
"ELI5: temperature changes and differences in dust, moisture, clouds, etcetera change what we see on the ground! Much more complex explanation: (I’m on mobile sorry for bad typing) sunsets aren’t blue because the water and nitrogen in the air cause Rayleigh scattering so most of the blue light gets filtered out and scattered (also why the sky is blue) but since the sun is low in the sky and therefore a ray of light spends more time in the atmosphere all of the blue light is stripped out. The colors we see in the sky are strictly due to more scattering of what’s left of the other colors and are due to different things like clouds and moisture and dust. Dust suspended in the sky is quite fine, so it’s actually somewhat transparent but only to certain wavelengths. Every element and combinations of elements has a well understood spectrum of what happens when light hits it. It will either absorb and in turn re-emit, reflect, transmit, or scatter. As the different types of dust and therefore a different combination of elements are in the sky as well as different moisture content, pressures, and temperatures (yes pressure and temperature do affect how light behaves) the sunset we see from the ground can be drastically different day to day and it’s also why sunrises and sunsets look different from each other. Source: I’m an optical engineer light do be my jam",
"The difference is in the location. Your sunrise comes from behind the picturesque mountains to the east, while your sunset dips below neighbor Cletus's run-down work shed.",
"Temp and barometer are both different at night and in the morning which changes how particles respond to air and light. On top of that, one is going up and the other down. I doubt color temp across the spectrum is different between the two but the fact they're opposite direction has to do something to your eyes. I think one thing that makes a difference is that the sunrise and sunset are actually just an illusion for the first and last 15 minutes respectively. When you see the beginning of the sunrise you're not actually seeing the sun but a reflection off our atmosphere. Even when the sun pokes over the horizon it's still not actually the sun. I assume reflecting from two different directions makes a difference in how it looks as well. There's enough differences between the two that it makes sense they don't look the same.",
"They don’t. In fact there used to be a website where you’d vote on which you were seeing, and it was fun because you couldn’t tell."
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mvmxsz | If atoms are 99,9% emptiness, how can they keep things together ? Like, if my skin is 99,9% emptiness, why is it able to keep blood and organs in it ? | Chemistry | explainlikeimfive | {
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"Touching, as you probably consider it, does not exist. All interactions take place at a distance - like magnets. While electrons are, as particles, incredibly tiny (even compared to other things on an atomic scale), they still repel other electrons and *very forcefully so* if those other electrons get too close. So, while an electron does not physically occupy the space in an atom, it still has claim to that space and will prevent other electrons from occupying said space.",
"Imagine atoms are balloons. Balloons are mostly empty space (air, but bear with me), but even so, balloons cannot pass through balloons. In an atom, the electrons buzzing around super fast on the outside form the 'skin' of the balloon. Electrons repel the electrons from other atoms, just like the skin of balloons make them bounce off each other. So your skin is a bunch of balloons glued together. Your blood is also a bunch of balloons, so it can't just slip through. Organs are lots and lots of balloons glued together, so they can't fall through either.",
"The [electromagnetic force]( URL_1 ) allows chemical bonds to form. These bonds give solid matter its rigid structure. At the atomic scale, particles can't pass through each other primarily because of a quantum mechanical effect called the [Pauli exclusion principle ]( URL_0 ). The Pauli exclusion principle is mostly responsible for keeping particles, like electrons, separate.",
"Try sticking your hand into a spinning aircraft propeller, and you’ll get the general idea.",
"It seems like you are thinking of protons and electrons in an atom as some sort hard, impenetrable bodies of a certain size -- like tiny billiard balls. If you are under this impression, then you would think that contact forces between these billiard balls are the only real forces that exist -- and so any action-at-a-distance, like gravity or magnetism -- likely seems very mysterious to you. Actually it's the other way around. Everything in the universe is action at a distance. Contact forces are just an example of action over very tiny, tiny distances. Atoms in a molecule or in a solid material are held together by electromagnetic forces -- the electrons in one atom are attracted to the protons in the other atom, however the two atoms can't get too close together or else the protons in the nucleus will start to repel each other. There is a certain distance where these attractive and repulsive forces cancel out, and that is what make atoms \"bond\" to each other. This bond distance is much larger than the \"size\" of the proton and electron (actually protons and electrons don't really have a \"size\" -- again they're not billiard balls, it's better to think of them as fuzzy clouds). But still pretty tiny, in human terms. Depending on a lot of factors, these bonds might be so rigid that the atoms can't move around at all (like in a solid), or they might allow for some viscosity (in a liquid), or they might be so weak as to be non-existent (as in a gas)."
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mvmyao | Can a tree stump grow back into a full tree? | Earth Science | explainlikeimfive | {
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"Depends on the species and health of the tree. Some store enough resources in their root systems to re-sprout from a stump. The stump itself doesn’t grow a new tree, but a new tree is generated from the still-living root system.",
"I don't see why not if the conditions are right. We cut trees all the time on our property. If they were healthy, they always sprout new branches from the trunk (at least the deciduous ones come to think of it). Most of the time we cut those back or even use a herbicide if we have to, but obviously we didn't want a tree there. If you cut a tree and just left the stump it would pretty much grow back if you give it time. Keep in mind, the open wound is a good place for pests and disease to get in, the new structure will never be as sound as the old and it won't look as nice as the one the stump came from."
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mvp1uw | Why does dizziness cause upchucking? | Biology | explainlikeimfive | {
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"Because your brain is tricked into thinking you've been poisoned, so it ejects its stomach contents.",
"It's just a precautionary measure in case your disorientation is being caused by poison that you've ingested, or possibly rotten food."
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mvpee2 | why does food get less crispy after it cools down/if you put it in the fridge? | Chemistry | explainlikeimfive | {
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"This is simply due to the humidity inside of the fridge. The water in the air softens up the food through absorption, especially food that is fried. Pro tip: put crispy foods in the freezer to preserve crispiness! Don’t put it in hot though!"
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mvq3ii | Why does varnish make paintings color pop more and become more clear? Why does it make the grain in wood come out and be more defined? Is it the same kind of thing? | Other | explainlikeimfive | {
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"Same reason polishing them does. A surface that looks oks flat is actually very rough at a microscopic level. All those various surfaces reflect the light in different directions. When it is varnished or polished the surface is much smoother and from any given direction the light is either reflected from the surface (looking like a “shine”) or it reaches the wood, paint etc. and then comes back at your eye with the color of the material."
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mvrvd5 | How do we “hear” the voice inside our head with no physical sound? | Biology | explainlikeimfive | {
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"When you talk and others talk to you, your brain lights up in places that process language. When you have an inner monologue, those same places (and some new ones) in your brain light up. Because the same part of your brain that listens to others is also listening to you, you process it as hearing a voice in your head.",
"The same neurons fire in your brain when you imagine something as when you experience it. So you can “hear” your internal monologue because your brain is effectively simulating the experience of you speaking.",
"Not everyone does. My misses has pictures, no internal monologue. She vocalizes a lot. She thought movies and tv that had a character's internal monologue were just doing it for effect, and \"crazy people\" had it until I told her most people have voices.",
"The really weird thing is that you can also change the volume of the voice in your head. Like, you can \"hear\" it yelling if you want."
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mvsxyw | How come we can't know exactly what is the population of a country at any time? | Why are censuses needed for this purpose? Can't we just count birth certificates and deduct death certificates, or count the amount of active ID cards? Aren't these numbers available on some database, or even multiple ones that could be brought together? Even though it's obvious that these methods won't be accurate to the individual, and probably for some countries not even available, why stops them being used? What am I missing here? | Other | explainlikeimfive | {
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"Delays in reporting and records being published to public databases. Sure, the hospital knows how many births and deaths they had that day, but that information may not be sent up the chain to higher levels of management for days or weeks.",
"Censuses collect much more information than just the number of people and are important for all the other data they collect. The population data from a census are usually going to be more accurate than trying to count birth and death certificates, which often aren't collected nationally anyway. To say nothing of immigration, illegal or otherwise, which can be very hard to count. A census is much like a stocktake that businesses do because errors and inaccuracies accumulate and you want to keep track of them. Not everyone even has an ID card.",
"From a US perspective the first issue is that the census is a Federal mechanism and all of the things you've mentioned are state-level things. Basically you're asking why the Federal government doesn't compel the states to give over demographic information about it's populous. The answer is: it can't. That's a design of a Federal government. There are limits to what the Federal government can compel the states to do. Remember back a few years ago when Trump demanded/requested voting information from the states? Many of the states refused because the Federal government lacks the authority to demand this information. Secondly, relying on things like birth certificates, death certificates, IDs, and such is the fact that you will be excluding people that don't have those things. You're taking for granted that these things are universal, but they are not, and the ways in which they aren't universal isn't random. If it was the case, for example, that there wasn't a significant difference, demographically and statistically, from people that have IDs that don't, then there probably wouldn't be an issue. But there is a difference, so by relying on IDs, you get a skewed image of the demographic breakdown of the US."
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mvtm77 | Why haven't new companies started filling the gaps in the market for long lasting appliances/electronics ever since many other companies have designed them to fail after a certain period of time to increase consumerism? | Economics | explainlikeimfive | {
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"There is no money in it. Consumers for the most part shop for the cheapest item that has the features they want. To make an item that lasts many many years would make it vastly more expensive. Also, technology changes so fast that after a few years electronics are outdated and being replaced anyway."
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mvu03r | How can the universe be infinite and at the same time ever expanding? | Physics | explainlikeimfive | {
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"The universe isn't expanding *into* anything. The universe *is* everything. So when physicists say the universe expanding, they mostly just mean that the space *between* everything is expanding.",
"There’s no reason to believe the universe is infinite. There’s also no reason to believe the universe is finite. It is, however, absolutely expanding, and we know this because every galaxy can be measurably careening away from one another, some faster than the speed of light. All this means is that matter has a speed limit, but space can do whatever the hell it wants",
"Usually the demonstration for an expanding universe is to draw dots on the skin of a balloon and inflating it. That will show how all the dots grow apart from each other in all directions at the same rate. But I feel that demonstration adds some unhelpful details. Like, sure, the balloon gets bigger, but if I put a box around the balloon, then it can't grow. The balloon is expanding into something. So what is the universe expanding into? The balloon model only makes sense when you consider the skin of the balloon itself is the *only* thing that exists. Above the skin, or inside the balloon don't exist. Your entire \"universe\" is restricted to the 2D space that is the balloon's surface. A flatland, if you will. It has no edges and is perfectly continuous. And as it expands, it needs nothing to expand into. It just does. It's still really hard to shake the idea that the balloon is just a 3D object that is expanding into a room, though, even though that's missing the point. Maybe a different way to look at things is not that space is being \"dragged\" off in any particular *direction*, but that space is multiplying. Space itself is literally spawning more of itself, everywhere, constantly. I have a galaxy at point A, and there's another galaxy at point B. I use a measuring device to see how far away from each other. I measure a distance of 100 imaginary space units. I measure it again a bit later and find 110 imaginary space units. Neither of the galaxies actually moved anywhere, ten new imaginary space units were just spontaneously created in between us. If you're wondering why space isn't \"bunching up\" on itself, well, why would it? It's not a tablecloth. Space doesn't need space to fit into, it *is* space. if extra space was spontaneously created somewhere, it doesn't need to \"fit\" there, it will just be created."
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mvu4i2 | Why do so many foster homes turn out to be abusive? Don't these people WANT to look after kids? | Other | explainlikeimfive | {
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"no. often times people are in it for a steady income or the power and authority they are given over a child by the state. it is a fucked up system we drag children through. I'm sorry.",
"You get paid to foster kids in your home. The amount varies, but it’s not insubstantial. A 2003 study by Grimm and Darwall actually examines the problem of foster abuse. You can get between 200 and 500 bucks a kid, per month, for fostering. All you have to do is be able to look like a good potential temporary home for kids, sadly. Additionally, while some people who abuse are in it purely for the money, some start out with good intentions, but a good percentage of foster kids have emotional, mental, or physical issues that can be frustrating to deal with. My parents fostered a girl the same age as my sister for a year, when we were all in our early teens. She had been abused badly. It caused issues with her behavior (hoarding, fighting, trying [@12] to use sex as a weapon), and eventually, while they never were abusive, they decided to stop fostering...although initially they were hoping to adopt one of the “future” fosters some day. People who want, or need, the income can’t just stop fostering, but they frequently do stop caring for the kids, in any real and healthy way. And while there certainly is some sexual abuse, the majority of the known instances of abuse are neglect-based, or physical abuse-based.",
"Like many things you see on the \"news,\" it's not as bad or as common as many think. However, many of the bad people do it for the money or they are people who never should have done it in the first place. They aren't patient or good with kids to begin with.",
"I can speak as someone who spent time in the CPS/CWS arena. Sometimes kids need to be removed from there parents due mainly to abuse, imprisonment, or death, if there is no next of kin, children under 18 become “Protectants of the State” (I thinks that’s what we were called in the 80’s). The state doesn’t want the responsibility for taking care of kids so like many other large corporations, they contract out the work. As we have seen historically, some contractors are better than others. There is no difference, some are great and do the best possible job & others do just enough to keep the money flowing. In truth most foster homes aren’t that bad. They feed you, clothes you, and make sure you go to school, even see a Dr. once a year. It’s the ones who tend to have multiple kids that are off the rails."
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mvuqds | What makes a melody "Christmas-esque" | I know that Christmas songs are only "Christmas songs" because we have come to associate a certain sound to a particular theme, but what is it in particular that makes that association? Is it a type of scale or instrument or "chord progression"? Same question but also for 80s music, 90s music, r & b, country, literally any classification of music. | Other | explainlikeimfive | {
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"You pretty much said it. It’s about the instruments and how they’re used as well as how the song was written and produced. Take 80’s music: reverse reverb snare hits, drum machines, synthesizers, epic guitar solos! Take country music: ‘traditional’ instrumentation (rock band plus mandolin, banjo, and slide guitar), specific vocal style (twangy) and harmonies, specific subject matters (trucks and momma). Christmas music: the bells!, lots of orchestra, the same song by 6 different people, lots of traditional songs from a million years ago, they say Xmas or talk about a holiday season"
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mvux4j | Does water have a maximum amount of solutes it can have, or does each solute have its own maximum? | For instance, say you have pure water -- 0 tds. And I put 10x, 10y, and 10z in the cup of water. Would the water have a limit: like holding 25 total, or would it be more like: 7x, 3y's 15z's? I hope this make sense (8/10) | Chemistry | explainlikeimfive | {
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"So get this, you can put sodium chloride in until it reaches its maximum, then if you tried to put sodium carbonate in, it wouldn't dissolve, cuz your maxed out on sodium, but if you put calcium carbonate in, it would, because your not maxed out on calcium or carbonate. Lookup the common ion effect.",
"Can someone do an ELI5 on the question itself?",
"Each substance has its own solubility. So even with a single solute there won't be the same amount of each in solution at saturation (the solubility). You may be able to dissolve 7 x but only 3 y, even when they are the only substance in the water. There is no one number of total amount of stuff that can be dissolved in the water. But mixing different chemicals does have some effect on the solubility of each other so you won't necessarily get exactly 7x and 3 y if you put both of them in your cup of water. There are several reasons the solubility shifts . The first depends on whether a chemical turns into *ions* in solution or stays as the same molecule. The second has to do with *activity coefficients* of the dissolved species. The third has to due with the formation of *complexes* in solution. Some substances dissolve in water by forming neutral species of the same formula as found in the solid. These are less affected by other dissolved substances. Hold that thought until we touch on activities. But some substances break apart and form ions in solution and these tend to be much more soluble. Salt, NaCl, is very soluble in water because if forms Na^(+) and Cl^(-) ions. Water molecules are slightly attracted to these ions which keeps them separated so you can \"fit\" more in solution. At saturation there is an equilibrium between the solid and the dissolved ions that can be mainly defined by the concentration of Na times the concentration of Cl. Same thing for potassium chloride, KCl, which forms K^(+) and Cl^(-) ions. So what happens if you dissolve as much NaCl as you can in water then add KCl? Now you have increased Cl^(-) so the value for Na concentration times Cl concentration goes up and solid will precipitate out until you get back to equilibrium. Whether or not the two substances share the same ions, there can still be an influence on each other. The presence of a lot of ions in water changes the *ionic strength* of the solution. The electrical charges interact between the ions and the equilibrium shifts. Finally, some chemicals can increase the solubility of others by forming new ions or neutral species called complexes in the solution. Sodium citrate is pretty soluble in water but lead oxide is not. If you put lead oxide in a solution of sodium citrate, some of the citrate combines with the lead and increases the solubility of the lead oxide."
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mvv8e0 | why does listening to music release feel good chemicals? | Biology | explainlikeimfive | {
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"This post had some good discussion. TLDR: Humans like to predict things correctly (dopamine rush when you recognize leopard spots through the underbrush), but also like to be surprised. So the third or fourth time you hear a song, you have both effects stimulating you because you broadly know what's coming next, but haven't memorized it. URL_0"
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mvxejq | if, for example, a Greek man is taught English by an English speaking person with no speech deficiencies, why does the pronunciation come out different? | Other | explainlikeimfive | {
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"Language is a physical skill as much as a mental one. Each language has a specific set of sounds or \"phonemes\" that when strung together make words. Each of those phonemes correspond to a different mouth and throat shape. Unfortunately for us, not every language shares the same set of phonemes. So each new language a human learns they need to master the physical mouth and throat shape needed to pronounce that phoneme correctly. On top of that each language has specific rules that can dictate how a letter is pronounced when in a certain position in a word. So pronouncing a phoneme at the start of the word that they have never had to before can throw off their pronunciation.",
"As a Greek dude I think I can help in this post! You know how a new keyboard always feels weird? It’s because your muscles have adapted to the shape and size of the old one. The muscles of your mouth also develop a certain memory over certain sounds. So when you pronounce certain words your mouth knows that when you go for a “u” sound they need to be in a certain position. Unfortunately this is not the exact position you need to have to nail down a perfect English “u”. Just like how in a keyboard you expect to hit cntrl alt but you hit windows space or something And because it’s good enough (I.e people understand you) you never develop the new muscles, especially since you go back and forth between languages",
"Some languages have unique sounds, most Asian languages struggle with with a hard \"r\" sound as an example. So it's unnatural for certain people to make specific sounds. It takes loads of intensive training to overcome those specific sounds.",
"Speech requires our tongue to acquire muscle memory to pronounce different sounds a certain way. So even when we learn a new language unless we keep trying to practice that accent repeatedly till we gain the muscle memory to be able to create those new sounds we will continue to sound like we have a different accent"
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mvxnym | why is math so commonly the subject that every child has hated? What separates math from the rest of the subjects? | Other | explainlikeimfive | {
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"Math requires ever more abstract thinking. It requires you to imagine a number of things and add or subtract another number of things from that. Most of the time you never see, touch, or manipulate those things. It's actually best shown with coins. Let's say I have 5 quarters, 2 dimes, 1 nickel, and 3 pennies. Now you know, in total, I have $1.53 of value, but value is an abstract thing. To a child I have 11 pieces of money so I have 11 total value. The fact that a quarter is worth 25 pennies or 5 nickels is beyond what they are able to grasp at first. However as the brain develops it gets better at abstract thinking. And math class challenges the developing brain just beyond what it is usually capable of in order to help develop that abstract thinking skill.",
"More than any other subject Mathematics is about a right and a wrong answer. Even Science is more about developing the critical thinking skills required to come to said answer, while Mathematics is almost exclusively about just which answers are wrong and which are right with minimal element of 'discovering' the subject. Kids don't like to just be told 'this is right' and 'this is wrong'. Hell, *people* don't like this, which is why conspiracies get so much truck: it's often seen as admirable or good to question what you've been told and some adults take that as carte blanche to question all the way to first principles even though they have no understanding of the subject matter.",
"Read [the mathematician's lament]( URL_0 ). Math as it is taught in US primary and secondary schools has nothing to do with how it is taught in undergraduate and graduate schools. It's taught as wrote memorization, which isn't fun, but then seques into algebra, which is problem-solving logic puzzles, which cannot be solved using wrote memorization. Like Carl Sagan observed, kids have the creativity crushed out of them in primary school, and then have to be re-taught it in college. Why not just don't crush it out of them in the first place? You'll save a lot of resources. Note math isn't the only problem. History as taught before college also has nothing to do with the academic community of historians. The Texas Board of Education dominates what gets put in those textbooks. Unlike math however, colleges have to re-educate freshmen regarding history. If you take remedial math it's because you didn't learn math; if you take remedial history it's because you did learn what you were taught, but what you were taught was lies.",
"I'm not sure but I think it occupies a completely different part of our mind. We must detach and assess problems objectively and learn how to solve things logically. Maybe the teaching technique isn't always right for the age group.. People complain that maths is abstract and has no real world application. But it teaches us how to solve problems. (Edit. *Some kinds of* problems. Not every thing can be solved with logic) As in, the headspace and working through the process. You can't be subjective in maths. Not that subjectivity is inherently bad, but sometimes it's not about your position",
"Probably because it is the most objective with the least leeway for interpretation and independent thought. Math is math, and kids want to be creative not controlled.",
"My experience is that I want to solve the equation in the way my mind works, and I definitely don’t want to show my work when I know the answer is correct. My sixth grader has the same issues, even with common core.",
"It’s definitely about the teaching methods. Generally math is boring, repetitive, and has no “real application”. I loved physics. I hated math class. Physics is literally just applied math, but physics is fun. You can do experiments and hands-on stuff to demonstrate the formulas. Math is usually “find X *because*” where other applied math classes have more of a tangible part that makes it more engaging."
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mvxoh8 | What’s the psychology behind commercials that barely mention or show their brand but still gain popularity? | I don’t understand the point of commercials that barely have any name recognition, or mentioning of their brand name? Like half the time I see a commercial and don’t even know what it was about or brand it was supposed to make me buy? For instance, Zillow just had a commercial about a girl with split personalities but the personalities all took physical form as her in a bunch of chairs in an office. The name Zillow was barely visible and not mentioned till the end and even when mentioned it wasn’t really emphasized. | Other | explainlikeimfive | {
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"> For instance, Zillow just had a commercial about a girl with split personalities but the personalities all took physical form as her in a bunch of chairs in an office. The name Zillow was barely visible and not mentioned till the end and even when mentioned it wasn’t really emphasized. You say it’s not effective but you’ve gone out of your way to ask this question and mention their company name twice. I’d say that’s an effective ad.",
"This technique is called soft sell advertising. The branding in these types of commercials is subtle because the emphasis is on telling a story. Bonus points if they can provoke an emotional response that viewers will subconsciously connect with their brand."
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mvyk93 | How is digital money different from paper money? | I am not talking about cryptos, but how a country starts to use a digital version of their currency. I mean we already make cashless transactions with Cards, Google/Apple pay, WeChat pay etc. Does it only differ in the way that we cannot withdraw it and make an untraceable purchase? What about currency conversion? | Economics | explainlikeimfive | {
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"Everything stays the same except you can't withdraw cash. The majority of money is digital already, and exists only in bank accounts."
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mvzivh | Why do barbers always slap a leather strap with a straight razor, before using? I get that it sharpens but how and how much? | Physics | explainlikeimfive | {
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"It doesn't sharpen, it hones. there's a difference. Sharpening is when you´re taking material off the blade to make a blade sharper or create a new edge. Now a good edge is very fine at the tip and will bend, honing basically bends it back to be as straight as it can be, it does not take off material. Now you can do both, some people sharpen their straight razors when they only need a small touch up by using diamond paste which is basically wax with diamond dust mixed in to it with the hone/leather strap. and this abrasive takes a bit off the top and sharpens.",
"They're honing and straightening the blade. Imagine the end of the razor blade is made up of lots of tiny razors. When it gets used, these razors can get pushed about a bit, meaning they don't all line up. By swiping the blade backwards along the leather strop (that's the name), all the tiny razors get aligned again, making it straight. It's similar to combing your hair. Sharpening a blade actually involves taking off a layer or metal. That's more like the tiny blades actually becoming blunt, so you strip them off to reveal a fresh layer below."
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mvzn6g | Why is it so hard to clench your fists when you just woke up? | Biology | explainlikeimfive | {
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"When you sleep, your body is flooded with a chemical to stop you from acting out your dreams. When you wake up, that chemical is still present and has to wear off. Kind of like any drug slowly wears off.",
"No movement. Lack of blood flow. Must wait til flowing actively which involves moving around. Much like leg cramps. Stretch too fast and you cramp/Charlie horse due to the slow/insufficient blood flow. There’s not enough oxygen or calcium or potassium right there where your muscles need it."
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mvzzj9 | Why do we feel things, like bugs, walking on us when there's nothing there in reality? | Biology | explainlikeimfive | {
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"What you perceive is influenced by top-down processing. What's that mean: bottom-up processing would be the sensory cells on your skin telling you something is touching you in some way. Top-down processing is identifying that sensation as bugs because that's what it feels like in your opinion (lots of little movements sorta randomly scurrying across your skin). You look: there's nothing there. Your top down processing made a guess and was wrong. The reason this is a top down process is because you're inferring what the sensation is caused by based on past experience and what you think is likely, rather than just passively experiencing a sensation. The sensation was probably just air, an itch, you rubbing against something without noticing, etc. Stuff you experience all the time and feels fine, even ignorable. But sensations don't always produce the same perception (experience). Our perception of a sensation is influenced by that top-down processing. And sometimes it misattributes sensations. And once we assume something is the cause of a sensation, we also start matching our experience to what we expect it to be: you swear you could literally feel the individual legs of a spider or something. Your brain forced that assumption to fit the sensations, and so it really did feel that way to you."
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mw0v98 | why/how did coaxial cable become the standard for radio to antenna interface? | Just wondering how and why it became such a ubiquitously good choice. I'm assuming because the copper cable offers the least resistance and reduces signal loss. There seems, at least to me, to be no have real improvements to this and am curious to know why. Or if there are indeed newer and better performing interfaces. | Technology | explainlikeimfive | {
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"You know how an antenna (or \"aerial\", in case your British) is just a metal rod or even just a piece of wire? Now, any antenna can not only receive radio waves but can also send them: if you feed a pass a radio signal as electric current through a wire, the wire will produce radio waves, which radiate out perpendicularly from the wire. Now, if you receive a radio signal from an antenna and want to transmit it to your radio or TV set, you wouldn't want the connecting wire to send most of it back out just into the air, because this way, the signal would leak out, and hardly anything would arrive at the other end of the wire. The point of the coaxial shape is to prevent the cable from acting as a sending antenna, as an ordinary wire would. In a way, the electromagnetic wave is trapped between the central wire and the surrounding shield and moved along through the cable. This works if the radius of the cable is well matched to the frequency you want to transmit",
"Coaxial cable has an outer cylindrical sheath with a second conductor at the core. Because the sheath completely surrounds the core, electric and magnetic fields are only created inside the cable, and don’t “leak” into the outside world. This is bad: it means your cable becomes an antenna radiating electromagnetic waves, and at high frequencies you can lose a lot of signal this way. But just as important is that antennas work as both senders and receivers. The outer conductor oof a coaxial cable also acts as a shield to stop electromagnetic waves from outside from causing interference.",
"The main reason is that coaxial cable is so good at containing the signal and rejecting interference, because the outer conductor acts as a shield. You can run a whole bunch of coax cables together with minimal transfer of signals between them, or from nearby electrical noise. Coax is more expensive, and it's \"unbalanced\", i.e., the two wires are different, so you need a \"balun\" (BALanced/UNbalanced converter) at the end, but today the benefits of coax outweigh the cost. There is still some use of simple twin-lead because it's cheap. It used to be quite common for TVs when it was all VHF, but it was often inadequate once UHF channels came into use because it needs more care in installation to deal with higher frequencies. For very high frequency work, microwaves and above, waveguides win over coax. These can be just a hollow copper pipe of a fixed diameter, and they have lower losses than coax."
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mw1e7v | how does our brain decide what noises to ignore when we sleep, and when the noise is "enough" to wake us up? | Biology | explainlikeimfive | {
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"It is also clearly a learned response. I had two small children at one time (now they're big), and each of them would wake up once or twice a night. My wife and I split the duties - I took the girl child, and she took the boy baby. After only a couple of days, I slept through the boy's cries, and she slept through the girl's, but each of us woke up immediately when \"our\" kid was crying. In the morning we didn't even know if the other had been up. Note that when the kids cried during the day, we usually couldn't tell which was which. But our sleeping brains did.",
"In simplest terms, it's based on potential danger level. If the sound appears normal or benign, your brain \"ignores\" it. If it somehow crosses that threshold, your brain will decide it needs more attention and wake you up. As you get older, though, that line gets a bit more \"blurry\" as you brain catalogs things that it will or will not wake you up for such as ambient noise while you fall asleep like the TV, radio, animal noise, or normal neighborhood sounds"
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mw1gst | Why are people with darker skin more tolerant of the sun/heat, when lighter colours are better at reflecting light? | Biology | explainlikeimfive | {
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"Melanin absorbs uv light which is the harmful part of sunlight. Darker skin has more melanin so less damage from the sun",
"Tolerating sunlight betters is not a question of heat tolerance. The damaging part of sunlight isn't the heat energy absorbed which human bodies can dispose of relatively easily. The difference in heat absorption isn't the key matter. Sunlight is damaging because of high energy radiation in the ultraviolet (non visible light) region. This kind of radiation can cause cellular damage and mutations. There is a compound called melanin in skin that helps mitigate this damage. Melanin causes skin to be darker - light skinned people generally have less melanin and therefore cannot mitigate as much damage from UV radiation. Don't, by the way, think that this protection is absolute. UV will do damage regardless so melanin isn't \"immunity\" simply some additional protection. Whether a person has dark or light skinned, over exposure is still a problem."
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mw2cq2 | What ecological role do nocturnal urban critters like skunks, raccoons and opposums have? | Do they still have the same ecological role in a city/urban setting that they would have in the wilderness? | Earth Science | explainlikeimfive | {
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"All three of them have pretty similar roles as small browsing omnivores. In the wild, they would eat choice plant material like berries, along with insects and small animals they might be able to catch. It's not that much different in the city, except for most of the potential plant food sources aren't around, but there are a lot more types of human leftovers tossed all over the place."
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mw2izd | how do barbell squats work the legs differently than deadlifts? | It's the same movement, the legs are pushing straight up from the ground. Can't figure out how one is supposed to target one area better than the other. | Biology | explainlikeimfive | {
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"Deadlifts you only bend very slightly at the knee whereas a squat you end in the sitting position.",
"A deadlifts uses more of your back and core because the center of gravity is in front of you. Squats have the weight above the center of gravity so you're engaging more legs. Deadlifts use more muscle groups."
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mw368j | How does the weather change so fast? | I’m not talking about the weather changing over a few days: I’m talking about how when I look outside the sky is quite cloudy and when I look again in an hour or maybe even 30 minutes it suddenly becomes clear, and looking around there are ZERO clouds in the distance. Where do the clouds go in that span of time? | Earth Science | explainlikeimfive | {
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"The distance to the horizon is typically a few miles to maybe 15 miles depending on your elevation, so looking all around you might be able to see 30-40 miles worth of sky (15-20 in either direction). If clouds above your head are moving at 20mph, they can easily blow over the horizon in under an hour. Also, clouds dissipate, sometimes quickly, depending on lots of factors (temperature changes, wind speed an direction changes, humidity changes, etc.). Combining your limited view of the sky with ever-changing clouds, it's not unusual to have a cloudy day turn into a sunny day, and vice versa, in under an hour."
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mw3o70 | Why doesthe human body pile on unhealthy amounts of fat, when the it can "ignore" significant amounts of other nutrients when not required? | Biology | explainlikeimfive | {
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"Evolution, fat is traditionally hard to come by so it is always considered useful and not to be wasted.",
"Our bodies are well adapted to tens of thousands of years of life before our modern age of supermarkets and food abundance. In the wild, fats and sugars are hard to come by for humans, so our body will make the most of them by storing the fats. Our body naturally craves them, but as we have only lived in a time where they are so readily available for a relatively *very* short amount of time, our bodies have not yet adapted to the change. I guess other nutrients are easier to come by in nature through foraging, so our bodies have worked out when to let them go when we have enough.",
"There are two categories of nutrients: macro-nutrients and micro-nutrients. The later are vitamins and minerals. There are three Macro-nutrients: fat, carbs, and protein. Nutrients have calories. Micro nutrients have “micro” amounts of calories. macro nutrients have lots of calories, and form the basis of our energy supply. When we consume more energy than we use, our bodies convert that excess energy to fat and store it, hopefully for use later. Our bodies don’t ignore the other two macro-nutrients. They play important functions in our body. We can cut out fats significantly and still gain plenty of weight or “fat”. That’s why there’s so much marketing aimed at getting us to cut back on carbs, because excess carbs easily get converted to fat. It’s worth noting the fat we store isn’t exactly the same as the “fats” we eat",
"Maybe a bad analogy. Say you live in some remote area in a cabin that relies on wood for heating. Preparing for a long winter, you'd probably stockpile wood which would otherwise be hard to obtain. It is unlikely you'll stockpile water because you can just melt snow to supply your needs and stockpiling it wouldn't be worth the effort. Similarly, the body learns through evolution. Energy (carbs and fat) are harder to come by and the effort to stockpile it when there is excess is justified. Many other nutrients are not urgently needed (ie you'd survive with a shortage for a fairly long time) or readily obtained in sufficient quantities. So the body doesn't waste the energy to hang onto it. This was of course more important when most humans had to hunt and gather. Agriculture and technology has changed all that but evolution hasn't had time to catch up on the new reality."
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mw4blo | Why is Southern Europe considerably warmer than Canada which sits on the same latitude? | Earth Science | explainlikeimfive | {
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"The North Atlantic Gulf Stream current brings relatively warm water to the areas off of the UK, making Europe have warmer weather than comparable areas in America and Canada.",
"Others have given good answers, I just want to point out that Canada has, by and large, the same latitude as central and northern Europe, certainly not southern. Like 80pct of Canada is above the 49th parallel (which defines most of the Canada-US border). If you Google a map of Europe with the 49th parallel drawn over it, you can see Canada in general doesn't overlap with any southern European states",
"It’s not just the gulf stream. Southern Europe being Spain, Italy, Greece, South France, warms up too because of the Mediterranean and the Mountains in central Europe blocking cold weather systems from the North from rushing in. The desert areas of North Africa also provide stable high pressure that is hot and arid. Canada has similar weather in Coastal areas such as Victoria, Vancouver. Due to the same coastal mountain landscape. Although there is more precipitation.",
"Is it at the same latitude though? Most southern point of Belgian (not south Europe and hardly warm) is the same as the big straight US/Canada border at 49°N. So I guess with Canada you mean the 2% most southern part of Canada? Edit: oké oké, the 'hardly warm' part wasn't completely necessary since OP didn't say 'warm' but 'warmer'.",
"I grew up in Vancouver, Canada and Istanbul, Turkey. The weather is not really that different. The winters are pretty much the same -- lots of rain and a few days of snow in both cities. It's rainer in Vancouver in the spring and fall than it is Istanbul, but the temperature is much the same. But, especially the last decade or two, the summers are much hotter in Istanbul than in Vancouver. It can get up to 40 celsius in Istanbul -- unimaginable when I was a kid. I assume this is due to both climate change and the heat the air-polution and now-concrete-megalopolis of Istanbul captures.",
"Because Southern Europe is protected by mountains from Northern cold weather and have warm African continent at the south. So warm air from Sahara desert keep Spain, Italy and Greece much warmer, while cold air from Scandinavia\\Russia is stopped by Alps.",
"It’s also worth taking about land masses, the uk Portugal Spain France Italy all very coastal the sea in general keeps the winters milder. Moscow is on the same latitiude as London def feeling a lot more cold there",
"Airstreams and atmospheric weather conditions created by geographical conditions somewhere. In its absolute basics; the same reason you can be located in the same areas, but if you side-step left behind a wall, it's not windy and cold anymore. The most interesting and easy examples are learning that hurricanes originate from specific geographical situations in Africa. Other places in the world don't get them because they're not across the ocean from those specific geographical conditions. Tornado Alley is also a cool one.",
"First of all southern Europe is not on the same latitude as Canada. *Lake Superior* is on the same latitude as Austria (Same size too). Not realy southern Europe. Secondly, southern Europe is as warm as it is, because it has a maritime climate, caused by the Mediterranean sea. The Mediterranean is very warm because it has little movement of water. Additionally the gulf stream heats up northern Europe. Which certainly has an impact on all of the Continent. There are the Alps, which have a large impact on European climate. There is the Sahara, which often blows warm winds our way.",
"Southern Europe (Italy, Greece, Spain) is not on the same latitude as Canada. Northern Europe (UK, Scandinavia) is, but the climate there is much more similar to Canada than to the warmer countries in Southern Europe.",
"Air and ocean currents. Western Europe in general has a bunch of warm water coming up from the Caribbean through the Gulf Stream. Meanwhile, the bit of North America where most of Canada's people are is sitting right under a big air current that pulls cold air down from the North. Also, the west coasts of things tend to be warmer than the east coasts because of the way Earth's rotation influences currents.",
"coastal drift, atmospheric conditions, sun angle and flair ups. there are a lot of variables in climate science.",
"To extend the conversation, since air and water currents play such an important part in moderation of the temp in these places, climate change may cause a huge change in the temps these places are use to should the ocean and atmospheric streams change course...",
"You know how when you flush a toilet it always spins one direction? Imagine the Atlantic is a giant toilet. When you flush the Atlantic the floaters spin from America's penis to Europe.",
"Continental versus maritime climates. Soil requires less energy to cool and heat than water does. The prevailing winds at that latitude are eastward so that is the direction in which thermal energy will distribute. You can see a similar phenomenon in Siberian Russia where the temperatures are the most varied in the world.",
"I lived in Southern Europe for a couple winters. It gets pretty damn cold. If it’s not an actual below freezing and windy cold, it’s a way worse humid just above freezing cold and windy too. The Russians I knew who were living there would complain bitterly about the cold in Southern European winters.",
"Europe is on the west coast of Eurasia, and the west coast tends to be warmer than the east coast or the interior. The west coast of North America as far north as Canada is actually quite mild especially compared to the rest of North America, though maybe not as warm as southern Europe. Europe is also much more exposed to the ocean than North America. The land is broken up by many seas such as the Mediterranean, Black, Baltic, etc which help moderate the temperature, where North America is just a big landmass where you can get over 1000 miles from any ocean. The Gulf Stream also helps bring warm water to Western Europe. Eastern Europe is actually quite cold, about as cold as North America, for these same reasons.",
"[gulf stream myth]( URL_0 ) > The Gulf Stream-European climate myth The panic is based on a long held belief of the British, other Europeans, Americans and, indeed, much of the world's population that the northward heat transport by the Gulf Stream is the reason why western Europe enjoys a mild climate, much milder than, say, that of eastern North America. This idea was actually originated by an American military man, Matthew Fontaine Maury, in the mid nineteenth century and has stuck since despite the absence of proof. Hence: 1. **Fifty percent** of the winter temperature difference across the North Atlantic is caused by the eastward atmospheric transport of heat released by the ocean that was absorbed and stored in the summer. 2. **Fifty percent** is caused by the stationary waves of the atmospheric flow. 3. The ocean heat transport contributes **a small warming** across the basin."
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mw4bmf | What is Dnm1l progressive mitochondrial disease? | Hey y’all. I am wondering if anyone could please explain what dnm1l progressive mitochondrial disease is. I ask because my young niece was diagnosed with it. I don’t really know much about science or medicine, so all the articles that come up when I google it are way over my head. From what the doctor told my Aunt, it seems to be rare and potentially terminal. Any explanation on what the disease is would be much appreciated, thank you. | Other | explainlikeimfive | {
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"Even more simplified: your cells have small things in them called mitochondria, which are necessary. When your cells divide (which happens frequently, throughout your body), the mitochondria divide, too, so each cell has the right number. In your poor niece, the mitochondria are defective. This means that the new cells might have bits of non-working mitochondria, and this can accumulate over time. In some cells, it doesn't matter much, because the cell can function anyway. But in other cells, it's critical that the exact right proportions work - like nerve cells. So as your niece grows, and the cells keep dividing, the problem gets worse."
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mw4egy | How do water treatment plants neutralize all of the different chemicals that are mixing in the sewers like toilet bowl cleaners, detergents, etc.? | Chemistry | explainlikeimfive | {
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"I'm thinking back a number of years to my studies so bear with me. There are 4 main steps they use in water treatment plants to ensure we have a perfectly healthy supply. The first is 'straining'. In which they remove large obstacles from the collected water. There's not much to imagine here, they just pass water through a screen. such as sticks and branches The second is 'Coagulation and Flocculation'. This is where they add coagulants to the water in order to collect much of the finer material which can get past the screens. such as dust and dirt The third is chlorination. Although it's more pertinent these days to call it 'disinfection' since we don't only use chlorine. We use these chemicals to kill any bacteria, viruses and parasites which may have passed through up until this point. The fourth is 'reverse osmosis'. This is basically the first step on steroids. We finally pass the water through a high pressure filter. The holes in this filter are microscopically small. So small in fact, that water itself can't pass through unless we put it under ridiculous strain. Considering water is already a comparatively small molecule, this filters out just about everything left.",
"Here in King County WA, we have sewage treatment plants of course, but we have a neat way of dealing with water run off (think buildings, parking lots, streets.) We use a series of culverts to divert the bulk of the water to a spillway. That spillway is a natural glacial reservoir with like 5 super deep basins. These basins hold and filter the water over months and slowly release it so a suburban creek for flow to our waterways. The basins have for generations been filled with moss and other cleansing bryophyta. In 2019, my school artificially amped up the amount of bryophyta to better combat the new chemicals being introduced to the environment. Over the wet months this area is a big bog. During the dry months it's an incredibly green pasture. But it does the heavy lifting for our \"surface\" water treatment. Source: a 3 year study on the hydrology of the 103rd St Basins to Thornton Creek."
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mw4l3n | why do mirrors reflect green more than other colors? | In another post about infinity mirrors it mentioned that the more reflections and deeper it goes, the more green the image appears. But they never said why this happens. | Physics | explainlikeimfive | {
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"The glass used to make mirrors has contamination in it. Those contaminates, particularly iron, make the glass slightly green. You don't notice this in a 'normal' reflection but the effect adds up as you stack reflections."
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mw4o1h | How do Space Agencies like NASA simulate antigravity training for astronauts? | I mean how can you just remove gravity without leaving the earth? | Physics | explainlikeimfive | {
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"Mostly in a giant pool, but also in parabolic flights (high arcing flight paths that free fall for enough time to do a bit of zero-gravity training).",
"The only way is to fall. So you can train and planes flying a parabola that represents a free throw wich makes the inside close to 0 gravity. There are also some falling towers, but they are mainly for 0g experiments and not for people.",
"It really depends on what you're trying to test. With general weightlessness in the ISS, you might train in a vomit comet (a parabolic flight that is essentially falling as fast as you). When you need to train for space suit usage though, especially training for a planned spacewalk, including the entire repair/maintenance sequence, you would train in NASA's Neutral Buoyancy Pool. They can adjust the parameters so that your space suit is fully neutrally buoyant -- neither sinking or falling. This is possible since you're in a suit that can have either weights or buoyant pieces attached to neutral yourself out. It isn't perfect, but it's a very close approximation. And then when you have something like training for landing the lunar lander.. well, that one is complicated. They needed to create rigs that offset gravity in real time, even as the rig might not be 100% level. Here's a good video with some more information: URL_0",
"Two methods, either by creating a balancing force in the opposite direction to make the total force closer to 0 or by allowing everything to be moved by gravity at the same rate so that weight is no longer a variable. Method 1: typically using buoyancy to “float” people and things deep in a tank of water. Method2: dropping everything at free-fall speed like in the “vomet comet” seen [here]( URL_0 )"
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mw51oi | Why are elements measured in their half-life rather than their full life? | Chemistry | explainlikeimfive | {
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"Because the decay is random. A half life of 100 years, for example, means that after 100 years, 50% of the substance will have decayed and 50% will remain. After 200 years, 75% will have decayed and 25% will remain. After 300 years 12.5% will remain. After 500 years, 3.125% will remain. After 1000 years less than 0.1% will remain. After 10,000 years less than 0.0000000000000000000000000001% will remain. It is impossible to predict when the last bit of the substance will decay, leaving nothing of the original sample.",
"Because their full life depends on how much matter you start with. Also it is theoretically infinite. The half life on the other hand is a fixed number. Radioactive decay happens at random. Every individual atom has a specific probability of decaying in a fixed period of time. If for example after 1 year an atom has a 1/2 chance of decaying, this means that after 1 year you'll be left with approximately half the atoms you started with, i.e. that element's half life is 1 year.",
"Half-life is a bulk property that’s caused by the random decay rates of individual radioactive atoms. When you have a trillion atoms of an isotope with a 48 day half life, about half of them will be gone in 48 days. If you wait another 48 days, the other half doesn’t all decay. Half of them do. It goes on like this for a long time. Any individual atom may decay today, or it may be one lucky bastard that persists for two dozen half lives. How long an atoms has survived so far doesn’t change the odds for the future so it’s impossible to predict how long a “full life” would be.",
"Because their full life is uninterestingly large. If you have a chunk of radioactive material, and it looses 1/2 its radioactive element in 1 year, then it's 25% in two years and 12.5% in three years and 6.25% in four years and even 100 years later, there are some radioactive atoms left in it. The 1 year half life tells you more useful information than the 1M year whole life would."
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mw57u3 | Why is the housing market so crazy right now? | Economics | explainlikeimfive | {
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"Covid increased an already booming market. Really overnight people: A. started to look away from apartments, big city living, etc towards more space and privacy. Small apartments are great if you have a very active social life but not so great for full time work from home, having a home gym, etc. B. Those with houses became very risk-averse and focused on home-improvement where they normally would have considered moving. C. As prices rise, homeowners are typically happier to stay in their homes while they gain value vs buying in at the top of the market on a new property. All of these reasons (amongst others) create extremely high demand for house and extremely low supply.",
"It depends on where you live. The reason is a mix of reduced constructions, growing population, and increased interest in speculative real estate (I.E. buying just to sell again later). There are also regions that are dirt cheap, simply because noone wants to live there.",
"There is an overall shortage of available housing, due to a combination of factors that have been exacerbated in the 21st century. Significant ones being zoning legislation slowing down new development of housing which has fell behind population growth, more people living alone than the \"traditional family unit\" in the past and the increasing percentage of housing being bought by landlords for rental portfolios. Unfortunately for first-time buyers, the laws of supply and demand mean that they are going to have to risk paying well over actual value to get their foot on the property ladder.",
"COVID has caused a number of shifts: - Many people want to move to bigger, more spread out houses. People in urban condos and apartments are looking for more space and a yard as a result of work from home, remote school, closure of many kids' activities. - Even people with starter homes were looking to upgrade to bigger family ones for same reasons -- they need that extra bedroom for a home office, want to install a pool, etc. - These are fairly common property steps one takes, going from apartment to starter house, from starter house to family home just more people all looked at making those leaps at same time due to simultaneous lifestyle shifts... - But this housing step up also depends on people moving from family home to a retirement home (whether that means a ranch house in Florida or an actual assisted living center). And many boomers/seniors didn't want to go out and look at homes in a pandemic. They didn't want people coming into their home to view it. They liked the additional space when stuck at home, especially if apartment-living adult kids chose to move back home for a time. - That set off a huge imbalance in supply for sale relative to demand for housing. Basic economics 101 is that if demand shifts higher and supply stays the same or shifts lower, prices will go up. - Low interest rates further fueled this. If less of a monthly payment goes toward interest, one can afford more house. The payment on a $300k house at 3% might be the same as a $250k house at 4%."
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mw5t5d | What determines a particular aircraft's rate of climb and rate of descent, and can their pitch ever safely exceed those angles? | If I'm flying a plane, what determines how quickly I can ascend? Is the most extreme possible rate of climb just as safe as a lower rate? Does optimal fuel consumption factor in? If I hypothetically just wanted to ascend as quickly as I could, what are the limitations and dangers and catches? Are there similar limits and concerns when it comes to descending? I've given this the "Physics" flair but if "Engineering" would be better I can change it. Thanks! | Physics | explainlikeimfive | {
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"You only have so much thrust available, and if you climb too quickly you will lose speed and that hurts your ability to create lift which is what makes you climb in the first place. Lose all your speed and you can't climb at all. In fact you will descend very rapidly. So, it's a combination of weight, thrust, and lift. Power gives you speed which gives you lift.",
"Its all just math at the end of the day. Ignoring factors like weather you basically have three numbers to play around with: speed, weight, and surface area of the wing. The more wing area you have, the more lift that generates (but also weighs more). You need air moving over the wings to generate lift, thats where speed comes in. And weight is the counter force to lift, you need to overcome that to fly. So depending on all those factors, it really varies on size of plane, design, cargo, etc. But for every set of those numbers there will be an optimal point like you're talking about, where you could punch in those numbers and find the optimal angle to take off at. For some of the other questions: If you pitch upwards too much that leaves less air going over the wing surface. If you reach a point where you are no longer climbing this causes what's called a stall. The pilot will begin to lost control unless they nose down and regain speed, therefore regaining lift. Depending is the same idea. The wings will generate lift still, and a controlled landing seeks to essentially fly level with the ground and lower the speed to the point where it just barely loses enough lift to touch the ground. If you want the most direct ascention you just ignore all these principles, build an explosion in a tube, point it up and strap some astronauts to the nose of that bad boy and set it off"
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mw662k | How come you can be exhausted all day and then at the end of the day be so wide awake and not tired at all? | Biology | explainlikeimfive | {
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"When you are stressed, like being tired, your body releases the stress hormone Cortisol. Cortisol can, among other things like reducing the stress response, shift your sleep pattern forward. What this means is, if you’d normally go to bed at midnight, now you’re really tired at 1 AM. At first glance you’d say “that’s not so bad” and you’d be correct. Except it’s a progressive shift. Every day it gets later and later until your “sleep time” is now during the normal waking hours. You might notice that it doesn’t stop there. It will cycle back to night and then day. It becomes a cycle that can be difficult to break.",
"Really for something like this it could be multiple reasons/answers. Boredom can have this effect. It can cause you to feel absolutely exhausted all day long, and then when you're home and able to be relaxed or do something you enjoy you may get an energy boost that keeps you up whether you like it or not. To keep on this same track if boredom causes the issue, but you can't sleep it may be your mind/body missing some sort of exertion. In other words pent up energy you don't realize you have because you felt exhausted all day. Depression can cause the exhaustion during the day as well and once you're \"safe/happy\" in your bed your brain may switch to a more energetic mode. Anxiety can play a role. Many people with anxiety can spend the day somewhat ignoring their triggers and then when in the peace and quiet of bedtime be unable to calm their brain down to sleep (my wife has this issue) Have you ever stayed awake more than 20-24 hours? At some point your body basically says \"ok, guess we're staying up\" and will produce endorphins that get your energy going for a bit. This can mess up your sleep cycle (which you may already be experiencing) Some people hit this wall before others. Especially if you have a sleep disorder of some kind like sleep apnea. If you ingest caffeine in the afternoon to help you through that last bit of the day it could be sticking around longer than you think and causing you to have sleep issues."
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mw66yh | What happens when we try to fall asleep | I'm just curious as to know how do we fall asleep, and how does our body know we are asleep | Biology | explainlikeimfive | {
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"Brain detects when it gets dark and releases a chemical, melatonin, which makes us feel sleepy and triggers the onset of sleep. This is why looking at a bright screen at night will make it harder to fall asleep and why there are blue light filter apps that help prevent that from happening, though an active brain also makes falling asleep harder. You can buy melatonin over the counter and people use it to help them fall asleep. It won't keep you asleep however, its role is only to initiate sleep."
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mw6rmq | Why does the road look like water on hot days? | Other | explainlikeimfive | {
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"Mirage. The hot road surface creates a gradient of air temperature. Light refracts differently through different temperatures of air (think of how air above a fire is wavy) This then allows the image above the road, like the sky, to refract back up to your eyes giving the perception of water on the road.",
"The hot road heats up the air above it, causing the light going through that air to be refracted into different directions instead of proceeding straight through. This causes anyone viewing that light to see it as wavy, sparkling, and hazy as light is coming into their eyes from places it normally wouldn't from that perspective."
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mw6ykm | Why can't a browser just stop and resume downloads later, like a torrent can? | Technology | explainlikeimfive | {
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"Most websites send you files by pointing your internet browser to their warehouse address and say \"Come pick up your package whenever you want it\" but your computer still has to do the work and go \"pick it up\" itself. You can't compartmentalize it (generally, but this is ELI5). With torrents, instead of being told to come pick up your whole package they basically have a whole bunch of different warehouses all around the world (One for screws, one for the wood frame, one for the couch cushions etc). Instead of being told \"Here's where your package is so come get it\" a torrent will first send your computer a file that's basically \"Here is an itemized list of every single box that you're going to need shipped to you one by one\" and the file is also a \"Here is how you let every single warehouse know whenever it's time for you to ask for their box/part.\" tl;dr Most websites just tell you to pick up the couch from their house but torrents will break it down and mail it to you one screw at a time Source: Am Network Engineer Edit: I know this is more like ELI12 but I don't think 5 year olds understand that we've taught rocks to do math. Also thank you for the award, anon.",
"Sometimes they can but it's up to the server that the file is being downloaded from to support the accept-ranges header which most of them don't: URL_0",
"A direct download is like a fully assembled piece of furniture. A torrent is like a flat pack ikea piece of furniture. If you deliver half of the single piece, it is now broken, and you have to deliver a full replacement later. If you deliver half of the flat pack components, then deliver the other half later, you can finish assembling it once you get them."
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mw7dpo | Assuming I sit at a desk for 8 hours per day, how much of an effect on my health would switching to a standing desk for 4 hours have? | Biology | explainlikeimfive | {
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"The current science actually says that the best thing to do is to have varied positions, so take frequent breaks, don't sit all the time don't stand all the time. Move fairly often. So 4 hours each still seems a bit high, but it would be an improvement over 8 hours straight sitting"
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mw7dr0 | What is the recent warp drive news about? | Physics | explainlikeimfive | {
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"It's a big nothing right now that's blown out of proportion by the media. There is no real basis for it. You need matter that doesn't exist, and doesn't have any reason to exist. It's just a fun thought experiment for the physicists to push the limits of GR.",
"To make a Albercurie warp bubble, you need to bend space positively and negatively. Mass and energy bend space positively, but there is no obviously way to bend it negatively. As a result you can, conceptually at least, make a black hole for the front of your bubble. If you had \"exotic matter\" with negative mass, you might be able to collect up a bunch of it to make the negative black hole, but \"exotic matter\" mostly means it doesn't actually exist. Some recent math has proposed ways to do this bending without exotic matter, using stupendous amounts of energy instead. Current theories predict that energy will create a black hole before reaching the necessary energy density, but the math folks are working on that. First, they need a more complete mathematical explanation, then we'll have to find if there is enough energy in the Visible Universe to do it.",
"The Lentz paper basically described a way to project a warp bubble without using negative matter or energy. This means warp tech has gone from from \"how do we make negative energy\" to \"how do scale up our tech to make this happen\". The technology required is still way too far out of our reach and the energy requirements are still enormous but it's an interesting path for future researchers to walk down."
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mw7h3k | () Why do some photos under a microscope rotate back and forth and why are some still shots? | Technology | explainlikeimfive | {
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"Hey, I am a scientist and microscopy expert. I'm not sure what you are referring to, do you have an example?"
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mw7qb9 | While blowing soap bubbles,why do some soap bubbles burst earlier than the others?And some bubbles take a lot of time to burst? | Chemistry | explainlikeimfive | {
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"First we need to understand how bubbles work. A bubble occurs when a gas becomes enclosed by another material. Bubbles can occur between liquids, gases, and solids, but for simplicities sake we’ll say that our bubbles occur when air becomes trapped in a soapy membrane. Any amount of gas has a pressure that it exerts on its surroundings so the walls of the bubble will expand outward, however, the atmosphere outside of the bubble also experts its pressure on the bubble inward. When these pressures equalize, the bubble stabilizes into a roughly spherical structure, as spheres have the smallest surface area to volume ratio, which is favorable in nature. Unfortunately, our ideal models rarely mimic reality. Even if your soapy mixture is distributed evenly and there are no defects in the bubbles structure, the environment around the bubble introduces too many forces on the bubble for it to hold together forever. A simple air current or even the energy from the heat of the sun or a light bulb is enough to upset the delicate structure of the bubble. Any bubbles that last longer than others most likely have a thicker membrane which would be more likely to absorb and distribute any energy it absorbs before breaking"
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mw80t3 | Does heating cheese to melting point change the nutritional value of it? If so...how? | Chemistry | explainlikeimfive | {
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"Not by much. The major components (water, fat, protein) are still going to be water/fat/protein after you melt it. The heat may denature (\"cook\") some of the proteins to a new configuration, which might have some very subtle nutritional changes but nothing macroscopic. If you get it hot enough to cook out the water it will be drier. But that's about it. Depending on the cheese, it may well separate and alter taste/texture/appearance, but that doesn't meaningfully impact nutrition."
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mw8m07 | How did they code the first computer without a computer? | Technology | explainlikeimfive | {
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"By hand, with switches and wires. You literally use switches to specify binary codes in machine code (the binary commands that the processor understands) and load those directly into memory, one memory position at a time, by manually specifying memory addresses (with other switches). It suuuuuuucks. Hence the relatively rapid invention of assembly code (human \"readable\" machine code), punch cards (ways to quickly set switches), and then compilers and programming languages.",
"The first computers weren't general purpose, their programs were hard wired into the CPU. Software and hardware can be interchangable. ENIAC was the first general purpose, programmable computer, in 1945. It was programmed through a card reader. You had a typewriter like device that would punch holes in cards. The card was printed with numbered rows and columns, and the placement of the holes indicated values in binary. This could be data, it could be CPU instructions...",
"As a person who used to do this for a living I can give you a direct explanation. * You would write the code by hand on a piece of graph paper. The language you used was a form of Assembly language that was one step less complicated than actual binary. * Then having checked this, you would translate, by hand, the Assembler into binary - 0s and 1s. This was also written on graph paper with one line for each bit pattern that needed to be set into each register of the computer. The result was a long table of 0s and 1s. Now you would have to set up the machine with the correct binary code for each register in core memory [See this picture]( URL_1 ). This was the control panel for machine I used to work on - the F1600B. The rest of it was a mass of electronics and hand-wired core memory in big boxes in a severeley air conditioned room. * The red switches on the right allowed you to move up or down by one register in the machines core memory * The long line of grey & green switches corresponds to bits in the core at the register you have selected. Flicking a switch down would set that bit to 1. * As you can see, the line is divided into a bank of nine on the left and three banks of five. The three 5 banks corresponded to three bytes. (only 5 bits per byte on this particular machine) Using the switches you can set each of those bytes to a specific binary value. * The nine on the left are used to set a binary instruction code that tells the machine what to do with the values set in those bytes. So for example you could set a code on the left that said \"add the contents of byte A to byte B and put the result in byte C.\" * After setting all the switches for a particular register you would then use the red switches to move to the next register and set the bits for that. Eventually you would have input a whole program. Eventually, this slow manual process of inputting binary values was replaced with punching holes in paper. In the commercial / IBM world they tended to use cards. In the case of real-time computers (military, air traffic control, process control, space etc) we would use a long rolls of paper tape. These were edited by physically punching holes in the tape which was 8 holes (one byte) across and read in by a paper tape reader. If you made a mistake you would edit your program by [covering holes up with editing tape and punching new ones]( URL_0 ). People got very good at reading binary. I could read through a tape and find a misplaced hole pretty quickly in those days."
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mw93g2 | Normal Force... | I just can’t wrap my head around it. I get that things don’t just fall through things, but like where does it come from. If I set a book on a table how does the table push on the book. | Physics | explainlikeimfive | {
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"Imagine yourself lying on a soft springy mattress. Your weight compresses the springs. Compressed springs “want” to expand to their original length, and create a force upward, pushing you up. The exact same thing happens when putting a book on a table. The atoms in the book (mostly the electrons “orbiting” the atoms) repel the top layers of atoms in the table, pushing them down. The atoms below them push up in response to being “squeezed”. If you looked really really closely at the table top you would see it being compressed just like a mattress, but obviously much less.",
"Electrostatic repulsion. The negatively charged electrons in the book repel the negatively charged electrons in the table once they get close enough to one another."
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mw9ecv | Why do humans bare teeth to show happiness when most mammals do it to show aggression? | Biology | explainlikeimfive | {
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"A smile doesn't just mean happiness. It's a social queue that can show many things including being nervous. Also, other apes use smiling in a similar way, such as chimps. So, like many human traits, they were adopted from previous ancestral behaviors (like \"smiling\" to show your teeth as a sign of aggression) to become much more social. Showing your teeth as a sign of aggression simply became *look, even though we're friendly right now, I'm still an apex predator, look! I even have these pearly whites that are for tearing up flesh hahaha we're so friendly right? Right? Now let's go work together and get some food. But remember... I can be aggressive if I want to so don't overstep my boundaries hahaha*",
"When we want to show someone acting threatening, we still show them with their teeth bared. See, for example: URL_0",
"The smile is related to the “fear face”. An episode of Desmond Morris’ “The Human Animal” addressed this question. When you smile, you’re showing fear, implying that you are not a threat, i.e. you are friendly. As others have pointed out, a key difference between the fear-face and the threat-face is aroud the eyes and eyebrows.",
"Basically our ancestors did so we still do. Blind people also smile without having ever seen one: URL_0 . Side note: those with autism have difficulty differentiating a happy smile with an angry face",
"My father was from Russia and none of my family on his side ever smiled. Recently I read this article and it mentions that one of the reasons Russians do not smile is because showing full teeth is “Vulgar” and resembles an animal. URL_0",
"Don’t know about you all but when I smile with my teeth showing it looks fake as hell. So I smile with my lips together.",
"When humans are really enraged, they bare their teeth. At least, they do so to me. If you haven't noticed this, maybe you're one of the charmed people that everyone likes.",
"It depends on the amount of teeth, and on the shape of the mouth and lips. The happiness smile is less teeth and more upturned corners of the mouth, which comes from the face we make when laughing. The more teeth we show, with less lips (curled lips) appearing, the more aggressive it looks.",
"It's thought that smiling in humans evolved from the \"fear grimace\" seen in chimpanzees (and a few other primates). It usually happens when the chimp is scared. In fact it resembles smiling so much that some people think they're being friendly when theyre actually very afraid. Since primates sometimes use the fear grimace to placate other, more aggressive primates, it's thought they we evolved smiling as a way to subconsciously show others that we are not a threat. [Here's an article about it in Scientific American]( URL_0 )",
"Actually, animals use an open-mouthed gape as a smile similar to how humans do, and humans bare teeth in aggression too. There's a chimp \"play face\" which is analogous to human smiles, and human grimaces and snarls are similar to more aggressive teeth baring in other species. But humans, unlike other apes, don't really use biting for aggression much (we have knives and spears and other weapons for that) and our canines are notably less developed than in other species. That probably shifts our \"showing teeth\" expressions more toward the \"play gape\" side than the \"snarl\" side",
"Oh! I actually know this one! My biological anthropology professor explained that most animals show their teeth to show that they’re scary and you shouldn’t mess with them. However, humans show our teeth to show that we’re not scary- because our teeth are much flatter than a lot of animals, our ancestors began smiling to show others they weren’t a threat. And here we are now :)",
"I've never thought about this, it's an interesting question. Most people are pointing out that we DO often bare teeth for aggression as well, but to more directly answer the question, I would think it has something to do with laughing - a laugh is perfectly natural, and shows your teeth with a smile, so I imagine happiness slowly just got paired with the facial expression as a result. Also, I think some other animals show their teeth when happy as well, ever seen a pitbull it golden retriever smile? They show teeth sometimes as well, so it seems to be a trend present not only in humans",
"It's worth noting that not every culture considers a toothy smile to be a simple expression of happiness or friendliness. For example, Russians tend to think openly smiling is indicative of stupidity or insincerity. Kids in the 3rd world country I grew up in smiled and laughed all the time, sometimes even if they didn't like you, were scared or angry, etc. So pretty much the opposite dynamic. & #x200B; These are just two examples but I think they illustrate that smiling isn't the same across all human cultures. Humans have lived in groups for long enough that bare teeth have lost (some of) their aggressive associations and been incorporated into our extremely complex system of nonverbal communication and bonding. Basically the apparatus for tooth-showing has always existed for us and our ancestors, and in nonverbal animal \"societies\" it tends to play a particular role in aggressive display, but humans are using it in an unusual way because that is pretty much what we consistently do.",
"Most animals don't have dental care so they're not happy when they show their teeth, hence the aggression.",
"The question rests on a false premise. There are no universal facial expressions in regard to emotions. If you'd like to learn more, see Lisa Feldman Barret's work. The quick and dirty version is that emotions and the facial expressions of them are cultural and specific. So there is really no answer to your question because there is no universal. [ URL_0 ]( URL_0 )",
"We do have a related expression where we display teeth for aggression: the sneer. Pulling the corner of your lip back to display your canine tooth to express scorn. Literally “baring your fangs”."
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mwaecu | What defines a poem/What are the defining factors of Poetry? | Other | explainlikeimfive | {
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"As a poet, I would say elevation of language and/or intent. If you’re purposefully configuring, arranging, and curating language to impart a specific feeling or message, and engender a certain experience in the audience, that is the creation of poetic quality. What makes good poetry is up for debate, but I would consider this the baseline."
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mwajwo | why does salt on stuff make water come out but eating a lot of salt makes you retain water? | Biology | explainlikeimfive | {
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"Water goes to the salt. Salt on top of food pulls water out to go to the salt. Salt in you keeps water from going out",
"Two things to keep in mind. First, salt attracts water. Second, the body takes the salt into the blood and cells. In the first case the salt is outside so it pulls water to the outside. In the second case, salt is in the body so water is pulled into the body.",
"Osmosis rule 1: you don't talk... Oh, wrong topic. Salt changes the density of water, as stuff is added, it gets more \"dense\". Osmosis thru a semi-permeable membrane (basically a fine filter, like a cell membrane) permits (small) water through, but salt is too big and cannot pass. Osmosis always tries to balance things out. When the salt cannot move, the water moves, until either the cell explodes (muhahahaha) or the density is equal.",
"As other people have pointed out, when you eat a lot of salt it makes its way into your body fluid. Most (2/3) of the water in your body is inside of your cells, and the sodium can't get in there. The rest is in the spaces around your cells, with a small part in your blood vessels. Water follows salt because of osmosis, so the water in your cells will start to leave them, causing them to shrivel up. This can be fatal if it's too severe! Luckily, we've evolved to be very good at dealing with this. Your brain has special cells that sense when they're starting to shrink and pump out hormones that trigger the kidneys to start holding on to a lot more water than normal--so you pee out more salt than water, and the balance returns to normal. These hormones also trigger the sensation of thirst, which is vitally important--your kidneys can hold on to a lot of water but they're not perfect, so you need to add some water to balance things out. TL;DR: your kidneys sense the salt and retain more water; your brain triggers you to drink more water.",
"Osmosis is in its very essence \"water moves where the consentration is highest\" Covered yourself in salt or salt in the air? You dry out. Eaten a lot of salt? Water stays inside you. Works the same when salting meat, dessicating stuff. The top comment has it right, just wanted a bit more in depth :p"
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mwbts7 | what is a chromosome? | Biology | explainlikeimfive | {
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"A chromosome is just a bunch of DNA, clumped up into a specific order and shape. Your DNA wraps itself around some proteins, like thread on a spool, and clumps up into specific shapes. And that consistency means that we can study them very closely - we can point to the spot on each chromosome that codes for each of our genetic traits - hair color, skin color, sex, etc. What's important about those chromosomes is that they're consistent - they're able to make exact copies of themselves so that when your cells grow and divide, each of the two new cells gets a full set - each cell of your body has the same copy of your whole genetic code. And each chromosome comes in pairs - we have two copies of each set of our genetic code, with one copy coming from each parent. Humans typically have 23 pairs of chromosomes - 22 sets of normal chromosomes (called autosomes) along with 1 pair of sex chromosomes."
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mwceeg | If your body is dehydrated why do you have to pee so quickly after drinking water? | You would think if your body is dehydrated that it would keep as much water as possible instead of eliminating some of it. | Biology | explainlikeimfive | {
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"Part of being dehydrated is that your body refrains from processing too much waste from your blood in to our bladder because it needs to expend water to do so. When you finally start hydrating again your kidneys start going back to work.",
"Not everyone knows this, but your body needs both salt and potassium to absorb water. If you are low on either of these, it will indeed go straight through.",
"The body uses water to remove unwanted things from your blood, digest your food, etc. It can't just absorb it all. When you pee, that's water mixed with substances your kidneys have filtered out of your blood like dead cells.",
"Your body can only make urine within certain limits. It is mostly water and the rest is urea and other waste chemicals filtered by your kidneys. Now when you are dehydrated and your Body is building up more and more of these waste Chemicals in your blood it may seem like it would be easy to just make pee with less water and more waste but your body straight up can't do this past a certain point so they keep building up. While dehydrated you may feel the urge to pee more frequently with little coming out and feel irritation in your bladder. Your body is just trying to manage its waste as best it can. So when you drink water after being dehydrated for some time your body says \"yes this is what I have been needing!\" And will immediately go to work to try and get back to homeostasis."
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mwde37 | If two photons approach each other, what is their relative velocity? | Physics | explainlikeimfive | {
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"You'd initially think that they'd perceive each other as double the speed of light, but that's actually not true. The speed of light, in a vacuum is the same for all observers no matter what their speed is. So, two photons approaching each other at c (speed of light) will perceive each other approaching at c and their relative velocity will be c because the frame of reference does not matter.",
"The answer is C, if photons could perceive time. The thing is, photons can’t perceive time. From emission to absorption the whole trip of any distance (across the Milky Way or across your living room) to the photon is instantaneous. I know the C answer doesn’t seem to make sense, but nether does time dilation.",
"I suspect you are asking about special relativity, and the fact that nothing \"can exceed the speed of light\". However, you can measure the relative speed of two objects as you observe them, and here it would be that they approach each other at 2c. Nothing can move relative to you faster than c. And here, you observer one photon moving at c, and another photon moving at -c. (the negative sign just meaning the other direction). That's all fine and good.",
"At c time from our frame of reference doesn’t exist. You can’t apply traditional dimensionalities to things at or past c"
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mwdflf | Why are filibusters such a big deal? It just seems like a bill might be delayed for 12-24 hours because someone keeps talking, but I’m sure I’m missing something that makes them harmful to bills. | Other | explainlikeimfive | {
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"The filibuster rules have changed, and now a bill can be effectively delayed forever by having one Senator go \"I could filibuster this, and unless you got enough people to override my filibuster, the bill stays in limbo forever.\" Under the old rules, yes, a filibuster was just a delaying tactic. But now, because the Senators don't actually need to be talking the whole time, they can delay it forever.",
"The filibuster isn't what most people think anymore. It's not a senator talking for hours on end. If you can't get 60 votes in the senate to agree they should have a discussion about a particular bill it's essentially dead. It doesn't require someone to talk non-stop any more."
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mwdqq9 | Why is it that our stomach expands when we take a deep breath but it is our lungs that are filling with air? | Biology | explainlikeimfive | {
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"Our lungs are like sponges. They don't have muscles. Imagine you glue a sponge to your hand, and give it a squeeze. It won't open up until you open your hand up and give it room to expand! We have some muscles in between our ribs that help the chest expand, but the best way to make sure your lungs get enough room is to give them space by moving softer things out of the way. The diaphragm is a muscle below the lungs that also separates the chest cavity from the abdominal cavity. The abdominal cavity is filled with squishy organs that are used to moving around, so when the diaphragm pulls down towards the stomach, there's a lot less resistance than against the ribs. The squishy abdominal organs can just move out of the way and stretch your belly out when the diaphragm moves down, giving your lungs room."
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mwelzk | What's the point of earwax? | Biology | explainlikeimfive | {
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"It moisturises your ear canal, helps fight infections and prevents dirt, dust and other crap getting in your ear.",
"If your ear was just a hole, it would eventually get clogged. Also, bacteria that land in it would have no problem dividing like crazy. Earwax is like a faucet that never turns off, which drags everything slowly out of your ear."
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mwez7y | Death caused by Hypertensive And Atherosclerotic Cardiovascular Disease? | Biology | explainlikeimfive | {
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"text": [
"your blood goes through a bunch of tubes called vessels. They died because their blood vessels got tighter(less blood can flow) and their cholesterol created a blockage. Hypertension means your blood pressure is high because the vessels are tighter, atherosclerosis is when plaque builds up in the arteries. Plaque is sticky, so it can stick to the sides of the vessel and stick to other plaque When you have both, your blood has very little room to flow through until eventually somewhere gets blocked entirely. It happens a lot in capillaries which is bad, but generally won't kill you, but if it gets bad enough it can block the bigger vessels. Then a large part of your body won't get blood, and if that part is a major organ you will die without serious interventions."
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mwfb4u | How does an SSL certificate work | Technology | explainlikeimfive | {
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"Encryption is a pretty deep topic, but here’s the rough shape: An SSL certificate has two halves. A private key kept private, and a public key that is shared. If something is “locked” with the public key, it can only be unlocked with the private key, and vice versa. So you know if a message from a website can be unlocked with the public key, it really came from that site, and you know if you lock something with the public key and send it back, only the server can open it with the private key. It’s a way for two halves of a conversation to verify that their messages can only be read by the intended recipient."
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mwfqkp | Does one bad apple spoil other nearby apples or doesn’t it? | It has recently become clear to me that there are two types of people: * some believe the saying is “one bad apple **doesn’t** spoil the whole barrel” * some believe the correct saying is the opposite: one bad apple **can** spoil other apples in its vicinity Which is the original phrase? Which is true, scientifically? | Biology | explainlikeimfive | {
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"Apples that ripen release a chemical which causes other nearby apples to ripen. An apple that gets over-ripe then goes bad has released a lot of this chemical, which causes any apples near it to ripen more quickly, which makes it more likely that they'll also over-ripen then go back. Then they'll release more, and it's a big chain reaction. The one bad apple has now ruined the whole barrel of apples.",
"Apples don't have to be bad to spoil the others. Fruit ripens when exposed to the chemical ethylene. Apples give off ethylene. So you can get unripe fruit to ripen by putting them in a bag with an apple. But if the fruit is already ripe it will become overripe and go bad.",
"Yes it does. This is in reference to when apples were stored in barrels to last the winter.",
"What psychopaths are you talking to that say “one apple doesn’t spoil the whole barrel ?"
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mwg4jc | Why does depression make simple tasks feel like hard tasks? | Biology | explainlikeimfive | {
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"Depression makes you tired. It makes you feel like all you want to do is sleep and then when you do sleep you feel like you haven't gotten enough sleep or you feel guilty for sleeping when you knew you had other things to do. So then when you're awake you see how much stuff you should have done or need to do and get overwhelmed and don't do it. At least that's how it is for me. To counter this I do a little at a time. On my first day off during the week I will just do laundry and put away stuff. On my second day off I do the dishes and scrub the counter tops and the floor. I try to look at it as, \"do I have enough energy to complete this entire task?\" If yes I do it if not I find something else to do this way things don't pile up and I feel like I did something."
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mwg8d8 | Why do ballpoint pens sometimes stop working at a specific spot on paper? | I often find a ballpoint pen will stop writing but be able to write just fine on a different spot of the paper. Even if I keep switching back and forth to two different areas, sometimes I can never get the pen to work in a spot. | Chemistry | explainlikeimfive | {
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"Ballpoint pens needs friction to cause the ball to roll and deposit ink. If a part of the paper has been smoothed down (for example by unsuccessfully using the pen, or by some glue) then it won’t roll and there won’t be any ink laid down. Because it’s dependant on the surface of the paper it will consistently happen at the same spot.",
"Got some oil on the paper (your hands are naturally oily). The ball stops spinning as it goes over the oil so it doesn't get coated in new ink. Oil also doesn't let ink through it."
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mwgbhm | Why is San Clemente Island only visible in the winter months? | I live near the coast in north county San Diego. My street has ocean views and is about 500-600 ft elevation. In the winter months, you can very clearly see San Clemente (41 mi) and Santa Catalina (27 mi) Islands. However, in the summer months they are NOT visible at all!! ELI5 why that is the case? | Earth Science | explainlikeimfive | {
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"Whenever I have a question like yours, that I want a real answer to (not just people’s guesses) I email a professor in that science at a local college. I’ve done this probably 10+ times and always get an answer. Not just an answer, every time they have explained it in way that makes sense and are super nice about it. One guy even drew a little picture for me!",
"The nearest point of San Clemente island to the mainland shore is the Southeast point over to Encinitas or thereabouts and that comes in at about 60 miles. You are definitely seeing a refraction which as noted is highly atmospherically and meteorologically dependent. You cannot actually see out 60 miles at 500' shore elevation, there is a lensing effect. Check out this info from a local scientist. I emailed him years ago about observing the islands from shore. URL_0 Cheers!"
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mwghbz | -Why does scar tissue, especially those following severe burns, deform skin so badly, and permanently ? | Biology | explainlikeimfive | {
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"This has to due with the formation of collagen. On normal skin tissue, there is a cross-weave of collagen proteins, in pretty much random directions. When forming scar tissue, the body wants to seal the wound as quickly as possible, and so the collagen is formed in a single direction. As for why they are permanent, surprisingly, they aren't. Most scars will fade away after a while (it takes a long time). The ones that do not fade however are ones that seem like an impression on the skin. Also, when forming healing tissues, extra tissue may form, causing what is called a Keloid scar, typical with severe burns. These do not go away on their own, but can be removed through treatment."
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mwh8ev | Why do we sometimes vibrate when we stretch in the morning? | Other | explainlikeimfive | {
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"It's not really vibrating, but more like a series of spasms. As we sleep, our muscles don't (usually) move a lot, and they get tight. When they are tight, they often can't stretch as far. This is why we stretch in the first place. However, we often OVERstretch because of how tight they are, which causes the muscle to contract involuntarily, which causes the shaking or spasming.",
"This is called pandiculation. All mamals do it, primarily when rising. It is very beneficial, especially for spine health. Unfortunately, most people unlearn this as we age/become self conscious. Keep doing it. You can relearn it and do it voluntarily too."
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mwhow0 | Why is Crimea described as essential to Russia’s access to a warm sea port on the Black Sea when there is a ton of Russian coastline just to the East all along the Black Sea? | Other | explainlikeimfive | {
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"Well first of all Russia doesn't have that much of a Coastline that would work. Only around 200km. The reason is that they can't put their Navy on a port inside the Sea of Asov. The Straight of Kerch is the only way out of there and that put your fleet in a very weak position. You wouldn't want your whole fleet trap because someone is blocking the strait. It's just an obvious choke point where the water isn't that deep. Second you need a deep water port. Because if the slope of the coast isn't steep enough, the boat can't get close enough to the coast. Which would limit the use of the port to only small vessel. Russian coastline directly on the Black Sea have very few deep water port. Novorossiysk, Tuapse and Taman. Tuapse isn't that deep to begin with. The port is also small and not really easy to increase in size. On both side of the port there is hills that make it hard to build on. There is also a slight slope on the eastern coast. I doubt they can make it into a proper military harbour. Novorossiysk is a deep water port and a rather good one, but most of the installation is already for commercial use. The Russian have a military harbour there, but it's not a big enough, not big enough for the whole fleet of the Black Sea. Even if Novorossiysk have a bigger port than Tuaspe it also have the same issue as hills on both size would make expansion of the port hard. So the military would need to take some portion of the port from commercial use, which wouldn't be good for the economy and highly unpopular for the population. It leave us with Taman which is all new. It was opened in 2009 and it rather small in scale right now, but opposite to the other two it have room to expand. If Crimea couldn't be under the control of Russia it would probably be the only place where the Russian fleet could go. But right now there is no installation for that to happen. It would take decades and a lot of money to build installation equivalent to those of Sevastopol. There is also the issue that there isn't any cities or town close to the port. Think how much more it will cost to build since you gonna have to bring worker from outside the area. Worst you gonna need thousands of sailor to maintain the fleet and those people and their family need a place to live, go to school, buy grocery, etc. You are talking about make a whole new town. It's possible some military base are this way around the world, but it took a long time to make. Finally, another issue is that Taman is 17km from the coast of Crimea. That's dangerously close to a foreign power to put your whole fleet there. It's just easier to have Crimea under your control and use Sevastopol with all the installation and services already there. In addition, Crimea also have a central position on the Black sea, allowing more control over the sea from there, than from the Russian coast.",
"The Black Sea is the only warm-water coastline available to Russia. Not only that, but the Eastern Mediterranean is a region that Russia has historically tried very hard to project its influence in. To do that, Russia needs a firm, established presence in the Black Sea, which the military garrison in Crimea is a big part of. They were happy to leave it under nominal Ukrainian control (with Russian troops based there) while Ukraine’s leaders were mostly pro-Russia. But the overthrow of the pro-Russia Ukrainian leader back in 2014 spooked them and they decided that they needed to take full control."
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mwizmg | I realize the owners of for-profit prisons are motivated to have lots of inmates, but wouldn't the government (ie law enforcement and politicians) be motivated to have less people in prison so they don't have to pay? | Forgive me if any of that was incorrect or ignorant. I'm not a US citizen. | Economics | explainlikeimfive | {
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"You're assuming the people who make spending decisions about the government's money care how much is spent, and that they don't have any sort of conflict of interest (like having a family member or friend in the prison business or having investments in prison companies). Neither of these is necessarily true. Also, someone running for elected office may be perfectly happy to spend tax dollars in such a way that gets them elected even if they know it's a poor use of money.",
"What is favorable for the government as an organization, and what is favorable for politicians, are often two very different things. Remember that many of these politicians depend on donations from corporate sponsors to fund their campaigns, and likely pursue jobs with corporate entities for themselves and their family. Spending government money to buy campaign donations and do-nothing jobs for your kids is a long tradition in US politics.",
"There was a judge in north east Pennsylvania that was getting kick back from a juvenile detention center for sending kids there. URL_0",
"Uhm no. Law enforcement gets paid to \"keep the peace.\" If there were no criminals they would be out of a job so they have no incentive to have less criminals. Politicians should want fewer inmates but there is an entire industry that lobbies politicians. Basically the prisons either form a group that gives money to politicians for their election campaigns or they give money directly. Or maybe they help pay for adds or just remind their employees that the local guy keeps bringing in funding for prisons. Personally I think prisons should be paid more as former inmates stay out of jail. That would incentivize them to rehabilitate the inmates instead of providing them with the bare necessities."
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mwj2q9 | why when you have diarrhea your body excretes liquids when you have to go, wouldn't it be better to just preserve the liquids than excrete it? | Biology | explainlikeimfive | {
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"The liquidy stuff that comes out when you have diarrhea is what the contents of your digestive tract look like after your stomach, liver, and small intestine add their digestive juices to the mix. Normally your large intestine at the end of the tract reabsorb all liquid which is what makes your poop a soft solid. When you have diarrhea, your digestive tract goes into purge mode and expels its contents without waiting for reabsorption. It's a reaction to toxins or infection, so it's generally better to sacrifice the fluid and potential nutrition in order to eliminate a greater threat.",
"The idea is you’re body is trying to expel suspicious material from the digestive tract — either because you’re in danger of being poisoned, or because a clever virus has figured out how to push that button for its own purpose of spreading copies of itself. The bottom line is water is the medium your body uses to expel that material. It’s like having a wash from the inside out. Basically, without the water it’s just normal stool. The gush of water is *the point* — to flush out the trouble ASAP.",
"I'm not sure I understand your question. When you have diarrhea there's something that your body needs to get rid of *now* and using a lot of liquid is the best way for your body to do that. & #x200B; How would preserving liquids benefit you here at all? Other than just the fact that you need water generally.",
"It *is* generally better for your body to absorb the liquid in your intestines, and get rid of it through urine if that's necessary. Diarrhea happens when something has gone wrong and your bowels are screaming omg wft bbq get this stuff out of here now now now."
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mwj489 | What does Aspirin do to us? | Biology | explainlikeimfive | {
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"So aspirin has a couple of therapeutic effects. It is known as a salicylate (this is important later on) and a NSAID, non steroidal anti-inflammatory drug. To start it is an antipyretic, also known as a fever reducer, much like Tylenol. It is also an anti inflammatory, aka stops swelling, and an analgesic, aka stops pain. It’s most common use though is for anti platelet which means that it lowers the platelet amount in your body in order to prevent clots, which can wreak havoc if they get to the lungs or brain. In the lungs it causes a pulmonary embolism and in the brain it causes a stroke. It also is used to prevent heart attacks due to these properties. If platelets are higher than 450,000 per microliter of blood, there is an increased risk for these clots. Aspirin will lower the function of platelets sticking together and prevent coagulation. However, you cannot give aspirin to a child as it can cause Reye syndrome, which is deadly. If you’d like me to go into depth about the other three effects let me know, but there are much better options for those, including for children. Edit: misspoke, evidence of comment down below. Sorry guys, doing multiple things at once!",
"It is a blood thinner and in that it reduces inflammation which is a cause of physical pain"
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mwj7fy | Why cant we just burn all our overflowing garbage and filter all the pollutants out? | You know like, make a big room for burning garbage with vents to the outside, but install big high quality air filters that can keep all the bad stuff inside? If lifestraw exists, why no airstraw? | Chemistry | explainlikeimfive | {
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"Sweden does this extensively, even importing waste from other parts of Europe to generate steam for heat and power. Cleaning the air is not cheap, but Sweden is doing it effectively. Landfills emit methane over time that, if not collected and used for fuel, also pollute the air. URL_0",
"Remember in Toy Story 3 there was that scene in the landfill and the garbage was being set on fire? Yeah, we do that. Turns out, we create more garbage than we know what to do with, which is why we used to ship a lot of it overseas. Garbage is mostly plastic, which, when you burn it, releases bad stuff like hydrochloric acid, sulfur dioxide, dioxins, furans and heavy metals—all are super bad for your lungs and are potentially carcinogenic. Now, can those be filtered? Theoretically, sure. But realistically, probably not. Fact is, there is just too much garbage to burn. Even if you were to find a way to filter it, the filters would be filled up within an hour and would end up not being worth it. Unfortunately, recycling today more won’t fix this problem. Only about 10% of the stuff we recycle is actually recycled—mainly because it’s hard and expensive to recycle, and also there are only certain things that can be recycled. Everything else is just tossed into landfills. To fix this problem, we have to make companies pay for the disposal and recycling of their products. Please recycle, use reusable products, and watch your carbon footprint",
"So there are some issues with this. One, it is already done in some places and energy is generated from the heat to produce power. Two, it is still bad for the environment, what do you do with the filtered particles? It produces lots of carbon dioxide gas, which is bad for the environment. There is still much more trash being produced than we can use these process on. We could scale up but it is way better to recycle, reuse or not produce the waste material in the first place. A great example is the plastic t-shirt bag... They have an average useful life of about 8 minutes I heard the other day. After that, it is a waste product.",
"ok there’s a lot of things wrong with this. Burning all the garbage would pollute the air, so if we used filters guess what it would pollute? The filters. Then what? We burn the filters? Chuck em into the ocean to release all that yummy carbon? No matter what you do with the filters next the carbon from that garbage dump fire will be released again. I get what you’re thinking, but it just wouldn’t work",
"Lifestraws do not filter everything. They cannot desalinate water and cannot remove heavy metals even though they filter down to 0.2 microns. It's going to take a very complicated/advanced and thus very expensive filtration system to do as you describe. Plus, not everything that winds up in the garbage is flammable, plus there is the possibility that something tossed now could be salvaged or recycled later, if it's not burnt to a crisp. A lot of plastic still winds up in landfills, if plastic recycling became cheap enough and profitable enough it could be possible to have people picking out what was already tossed to go through the recycling process."
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"https://energynews.us/2013/10/17/is-burning-garbage-green-in-sweden-theres-little-debate/"
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mwjltj | Why are wires generally preferred over ACH when transferring larger amounts of money? | Title. Noticed transfers of over $30k+ generally are done over wires and ACH isn't accepted, why so? | Economics | explainlikeimfive | {
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"ACH (actually EFTS specifically as wire can be done through an Automated Clearing House too) requires just routing and account number, and in a legal sense is recognized as similar to a personal check. Wire transfers require two numbers from the bank that aren't easily-accessed public knowledge that you can find on anyone's checkbook, and only a sender can authorize money moving unlike EFTS where the receiver can also make money move like with automatic bill payment. In this sense it's treated more like a cashier's check. If they use FedWire, that money can be moved in the same business day (or even instantly) also, which is pretty handy. Not sure if FedACH is set up the same way, but FedWire is served by a datacenter with on-site backup, with another \"hot\" backup a few hundred miles away with *its* own backup of the backup, and a third \"warm\" backup facility. Even though the process is very quick. This provides a lot of integrity and failsafe to those big amounts of money.",
"Banker here: In addition to what was mentioned, Wires are guaranteed funds. Unlike ACH where it can bounce or be insufficient. The best way to think of it is like an ACH being the online equivalent of a personal check, and a wire being a cashiers check",
"The payee in a wire transaction prefers it because wires are nearly impossible to reverse. ACH payments can be reversed in certain circumstances. So less risk in a wire transaction for the receiver of the funds."
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mwjobq | What does the stomach’s microbiome do? What role do probiotics play for the microbiome? | Biology | explainlikeimfive | {
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"Your body does a lot of things with honestly not that much genetic material, however, it's not able to do *everything* that we need. Some chemical processes are only really done by bacteria, and we coopt these bacteria, give them food, and they give us the processes. A large number of these processes occur in the intestines during food processing. Probiotics *are* those bacteria, and eating probiotic foods reintroduces them to your microbiome after they may have been killed, like in a round of antibiotics."
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mwk3au | How can humans be allergic to eggs, but not chicken? | My girl and I are navigating her new dietary restrictions and she has no problem eating chicken but a test revealed she is allergic to eggs. How is this possible? | Biology | explainlikeimfive | {
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"text": [
"Hi there! So, the proteins and substances in chicken meat and eggs are different. Your friend may be allergic to either the albumin (the white of the egg) or something inside the yolk. None of these substances are in the meat itself. It’s mainly actin and myosin (muscle fibers). Yes they come from eggs, but they’re made of completely different material once the chicken is grown. P.s I’m allergic to chicken dander but not chicken eggs or meat. It’s all about the specific substances.",
"The same reason lactose intolerant people can eat steak. Just because they're from the same animal doesn't mean they're the same material.",
"It's like asking, how can I be allergic to tree pollen, but not allergic to wood. They are two different substances even if they both come from trees.",
"It's like wondering how humans find potatoes delicious, but potato leaves are poisonous..."
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mwkrpi | Could you use plant hormones or steroids to make trees grow faster and also larger like the giant redwoods? | Biology | explainlikeimfive | {
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"text": [
"Faster, yes. Larger, to an extent. Pushing things beyond their \"normal\" genetic maximum size comes with a ton of negative effects. Humans who have grown to be 8ft tall end up with blood pressure and heart problems as the physical weight if the blood puts stress on the heart. The same thing will happen to plants. Plants that grow larger than their normal will fall over from their own weight and die much sooner.",
"You could use them to encourage growth yes. But like every other living creature, trees are still bound by their DNA. So they can only ever get so big. A pine tree will never be a redwood, but you could get a much larger than normal pine tree."
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mwlamn | Why does room temperature water feel freezing but a room temperature room feel warm? | Physics | explainlikeimfive | {
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"text": [
"When you feel hot or cold you're feeling changes in how fast your body is shedding thermal energy or absorbing it once you get over body temp. Water, partially due to its nature and partially due to just having a lot more mass in contact with you thanks to its density, can absorb MUCH more heat than air in the same amount of time. So at a given temperature difference it feels \"colder\" as it draws more energy out of you. This is also why a bried splash of boiling water around 200* can burn you but a blast of 400* air from opening the oven is merely uncomfortable. The water, despite the lower temperature, is carrying MUCH more energy it can impart to you.",
"Convection, essentially. Water is a great thermal convector while air is an ok thermal insulator. Water will suck warmth from your body rapidly, air will leech warmth from your body slowly. To add to that, the little hairs on our skin help to \"trap\" a layer of air that warms up and acts as a bit of a thermal layer."
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