title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
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[
"Assuming we had (nuclear?) power plants producing electricity at 'near zero' cost, - what technology or process would we then use to product a liquid energy store?"
] | [
false
] | Synthetic petrol, if you will, but not synthetic in the biomass/corn sense. | [
"Hydrogen is the easiest one to produce (but maybe not to use)."
] | [
"So think about the fact that hydrocarbons are really really great stores of energy. They're stable (not really likely to explode), not particularly volatile (evaporate slowly relative to say, pure hydrogen), and have high energy density. Oh, and we already have an extremely well developed hydrocarbon infrastructur... | [
"BS hard to use. Just mix tiny amounts of it with regular air, light it on fire, produce electricity with a microphone."
] |
[
"How would gravity work with planet sized non-spherical object (for example a long cylinder)? Would gravity be stronger at the ends compared to the middle of the side?"
] | [
false
] | If you stand on the end you would have say 15km of material beneath you, pulling you down. But if you stand on the side you would have only 4-5km of material beneath you, pulling you down. | [
"No, the statement that gravity acts through the center of mass is incorrect. It is correct in some simple cases, such as spherical objects when you're located outside the sphere. But there are counter-examples.",
"One such example is a hollow sphere, where you are in its interior, but not in the center. While yo... | [
"If you're off from the end of the rod, the gravitational field is the same as a point-mass located at the centre of the rod.",
"If you're near the middle of the rod, and it's very long, the gravitational field will be twice that of what is felt from the end. You can think of this as being able to get closer to t... | [
"In the limit that the rod's length is much larger than its diameter, and you are close to the rod, the direction of the gravitational force is towards the rod's axis rather than towards the center of mass. This is because a very long rod can be approximated as infinity long and an infinitely-long rod has no center... |
[
"Why is it that when one's eyes or nails turn yellow is it a sign of liver failure? Why yellow? What is taking place for this to happen?"
] | [
false
] | null | [
"What you're describing is called ",
"scleral (or conjunctival) icterus",
" (literally yellowing of the white of the eye), and it is a sign of jaundice, which describes a state of excess bilirubin in the body. Bilirubin is one of the breakdown products of hemoglobin, and is normally conjugated in the liver to ... | [
"This phenomenon is called jaundice and is associated with a number of diseases and there are different mechanisms involved. The main culprit is bilirubin - a breakdown compound from red blood cells. Bilirubin is insoluble in water and is transported to the liver where it is attached to a sugarish molecule, making ... | [
"producing the dark brown color of your stool",
"A bit in the novel version of \"Silence of the Lambs\" has Lecter telling the FBI that they should go after one (non-existent) \"William Rubin\". Lecter was amusing himself by giving them such a shitty clue."
] |
[
"How do huge structures get buried?"
] | [
false
] | Huge structures such as houses, pyramids and whole cities that are hundreds or thousands of years old are often found below the surface, often while digging for construction. My question is how can these tho vs simply get buried? Esp. In places where humans have always lived and nature hasn't reclaimed the settlment. | [
"I would say that Kolmanskop in Namibia is a good example to bring up, with weathering, in how buildings, particularly those near deserts/loose sediment, can become buried from the weather. The straightforward process in this example being; sediment is carried by the wind into buildings, where it builds up against... | [
"I would say that Kolmanskop in Namibia is a good example to bring up, with weathering, in how buildings, particularly those near deserts/loose sediment, can become buried from the weather. The straightforward process in this example being; sediment is carried by the wind into buildings, where it builds up against... | [
"You are mostly describing how buildings get old and fall apart. He was specifically asking about getting buried. Where does this 5 meters of earth come from?"
] |
[
"Is it possible to think about a sound that cannot be created/replicated?"
] | [
false
] | null | [
"My favorite color is purplish-orange. My second favorite is greenish-red"
] | [
"My favorite color is purplish-orange. My second favorite is greenish-red"
] | [
"Do you mean Periwinkle? "
] |
[
"Are there any enzymes that catalyze inorganic molecules and hydrocarbons ?"
] | [
false
] | Can I get their names, if that is possible? | [
"I'm not sure what you're asking. Enzymes catalyse specific chemical reactions, like the synthesis or degradation of a molecule. I don't think that saying that an enzyme catalyzes a molecule makes sense. Also, inorganic molecules and hydrocarbons are different things. For chemists (and biochemists) organic molecule... | [
"I would look into deep-sea vent biology and chemosynthesis for examples of inorganic biocatalysis and methane metabolism for leads on hydrocarbon biocatalysis."
] | [
"Yes, there are enzymes which catalyze reactions involving those. An example off the top of my head is catalase, which breaks down hydrogen peroxide (H2O2), which is an inorganic molecule. From a quick google search, I found ",
"this",
", which seems to be able to break down the C-H bonds in hydrocarbons."
] |
[
"Why do vacuum-tube amplifiers sound so much louder, per watt of output power, than their solid-state counterparts?"
] | [
false
] | [deleted] | [
"Did you check if the 100-watt digital receivers are actually \"100 Watt peak-to-peak\" ? ;)",
"Old electronics were measured properly (RMS). Later marketing has turned output power to a lie.",
"In other words, if output is measured correctly then 100 watts is always 100 watts and should sound the same.",
"Ed... | [
"Exactly, a 100Wpp receiver would only be around 35Wrms."
] | [
"disclaimer- i am not a musician, and know very little about the specifics of guitar amps, so this is largely speculation- i do have a little background in electronics, though not professionally, so take my thoughts with a grain of salt...",
"i think this has more to do with the perception of sound than the actua... |
[
"If your muscles are passively moved, would your heart rate go up?"
] | [
false
] | I remember an electric exercise bike from years ago and it made me wonder if you could be completely relaxed and your muscles were moved passively, would your heart rate go up? Would the muscles being moved (contracted and lengthened) respond in some way (for example, increase in bulk) similar to how it would if they w... | [
"Your heart rate would not increase as a result of the movement. If it were to increase, it would be due to you psychologically reacting to the situation or otherwise. But since you aren't using energy (ATP) to move your muscles and exert force on the bike, your heart rate isn't going to go up."
] | [
"My thoughts were that movement of the limbs moves the muscles contracting the veins that are within which in turn moves an increased amount of blood back to the heart. This increased blood coming back to the heart forces the heart to do something with that blood, and so it pumps faster. "
] | [
"If anything happened there would probably be a decrease in heart rate to compensate for the increased blood flow from squeezing the veins, all other things being equal."
] |
[
"What are the characteristics that allowed multicellularity to evolve on earth?"
] | [
false
] | null | [
"But cells in a multi-cellular organism live side by side. They don't engulf each other. How can a bacteria engulfing mitochondria(if that is indeed the reason for cells containing mitochondria) be evidence for multi-cellular organism evolving? A multi-cellular organism is nothing like a cell containing mitochondri... | [
"There is a nice explanation of how eukaryotic cells evolved, but the OP asked about multicellular life, which is a bit different. In some sense, multicellular life is pretty simple - you just need cells to decide it is easier to stick together than remain apart. Bacteria do this when they form a ",
"biofilm",
... | [
"As is usual in nature, all these challenges can be addressed in a slow creeping manner - eg by starting with just a two-celled species, then a 4-celled species, etc"
] |
[
"When a solid physical object is broken into two pieces. Why don't the pieces fuse back together when hold together tightly?"
] | [
false
] | My understanding is that molecules are attracted to each other by Van Der Waals forces, and the atoms in the molecules are held together by the strong nuclear force. So when you put the pieces back together, and they fit perfectly, shouldn't they fuse together again? what is preventing this from happening? | [
"A few reasons. As ",
"/u/airbornemint",
" said, you'll never get them back together perfectly. Further, even if you had two pieces of identical metal, polished to the highest tolerances capable and perfectly flat, you'd never actually get them close enough to reform those bonds, at least while in the presence ... | [
"Yes, do it inside a vacuum chamber; it is already used in some types of nanofabrication."
] | [
"Yes, do it inside a vacuum chamber; it is already used in some types of nanofabrication."
] |
[
"How big would a cube of Lead have to be for it to be unable to hold its shape?"
] | [
false
] | I would think that if you had a cube of lead that was big enough, the weight pushing down on the bottom half or fifth etc. would deform it into a trapezoidal looking shape. At what dimensions would this occur? | [
"A related question: if the cube were floating in outer space, how big before its own gravity would pull it into a blob? ",
"And the bonus question, how hot would it get in the process?"
] | [
"Distortion occurs at any dimension. It depends on noticeable you want the effect to be. If you know Poisson's ratio and Young's modulus for lead the calculations for any size block are trivial."
] | [
"I did some math and I got the same answer as PhatZounds.",
"Assume you have some column of lead with cross-sectional area \"A.\" Pressure is just force over area, or ",
". The maximum force experienced will be at the bottom of the column of lead of length ",
". Now, force is given by mass times acceleration ... |
[
"Assuming a modern refrigerator of average capacity/efficiency; further, assuming standard use: would the presence of 0.5m^3 of water inside acting as a thermal \"battery\" have any effect on the system's efficiency?"
] | [
false
] | ...or is this one of those "Newton's Second Law" things where you'd never fully recoup the energy you put into cooling the mass of water in the first place? If we need to define "standard use"; lets say we open the fridge five times a day for five seconds each time. Thanks for your time and your expertise. | [
"I don't think you are correct. Let's take this to the extreme...the entire interior of the refrigerator is filled with water (in a container). Now, when the door is opened/shut, there is virtually no influx of warm air, replacing cool air and causing the refrigerator compressor to do work to cool it. The water ... | [
"As someone else stated, all you would do is add thermal inertia to the system. You would increase the amount of time it would take to change the system from one state to another, but you would not effect the steady-state operation. ",
"Assuming you disregard opening the door and allowing air to move in or out o... | [
"Zero effect. ",
"The water won't change the amount of heat lost through the exterior. All it will do it add thermal mass, thus 'softening' the warm/cold spikes the interior will experience as the refrigerator cycles on and off, or the door is opened/closed. The presence of water won't affect the opening and clos... |
[
"How are hazard ratios interpreted?"
] | [
false
] | I am curious about the interpretation of hazard ratios, particularly from this study: . I thought it used to be open access, but if it was, it isn't now. Their conclusion was that a high intensity of exposure to formaldehyde leads to a much higher risk of ALS death. It's somewhat confusing because they never address th... | [
"I don't know too much about this, but this seems like a nice explanation: ",
"www.medicine.ox.ac.uk/.../what_are_haz_ratios.pdf",
"Essentially, a hazard ratio is the probability of an event (in this example, ALS mortality) in some experimental group (respondents exposed to some level of formaldehyde) at a give... | [
"My main question is how do you interpret hazard ratios? And why does it look bimodal here, meaning a medium risk leads to lower risk of ALS death according to the HRs?",
"Hi. Hazard ratios determine the likelihood of a negative event (ex: ALS mortality) compared to some reference group (ex: unexposed people). ... | [
"Thank you. I spent a good amount of time even figuring out what HR stood for, because they don't define it in the publication.",
"You can find a pdf of the publication online.",
"Are hazard ratios the same as odds ratios? I know how to calculate and interpret odds ratios. If so, that clears things up. I use th... |
[
"What kind of events/circumstances would it take to cause a world-wide winter/another Ice Age?"
] | [
false
] | I am aware of nuclear winter and gamma ray bursts possibly causing it, but is there other non-nuclear/non-radioactive ways that another Ice Age-like event could occur? Edit: I'm asking because I'm writing a novel centered around Earth turning into a frozen wasteland. | [
"A sure fire way to cool rapidly is an impact event or super volcano eruption. Throwing billions of tlnes of ash and smoke into the atmosphere causes cooling. However, the timescale of the cooling may not be long enough to create the world you are imagining. Also, if the impacter is much larger than 1-2 km in diame... | [
"How poles reversing can affect climate? \nSerious question."
] | [
"They've been watching too many disaster films. There is zero evidence that a magnetic pole reversal would cause any climactic weather events and being that its a process that is thought to unfold over half a million years no human has ever been alive to challenge that theory.",
"Now a physical pole reversal woul... |
[
"Why is it that some particles interact with the higgs field and some don't?"
] | [
false
] | I have a very VERY basic understanding of what the higgs field is and what it does but I'm not sure sure I understand what makes particles react with it. So... what makes particles react or not react with it? | [
"There is currently no known theory that explains why the various higgs couplings have the values that they do. All we can do is go out and measure them.",
"The Standard Model of particle physics is built out of gauge symmetries, which means that when we create the theory we impose some specific mathematical stru... | [
"dern questions... be there no end to them?!?!"
] | [
"I would like to think that's the true glory of science and existence as a whole."
] |
[
"What stage of sleep are people in when they are in a coma?"
] | [
false
] | null | [
"They are not in a stage of sleep.",
"Here is a good chart describing different mental states relative to each other:\n",
"http://www.google.ca/imgres?um=1&hl=en&biw=1920&bih=926&tbm=isch&tbnid=ko1yWxKam3VoOM:&imgrefurl=http://www.sciencenews.org/view/feature/id/337940/title/Emblems_of_Awareness&docid=f4-q1QapJ... | [
"In Catatonia you are fully aware meaning you have primary and secondary responses to sensory stimuli, for instance if someone calls you name your brain will respond very differently than if someone calls out the word spoon (your brain will recognize your name being spoken and trigger the emotional and cerebral res... | [
"i mean like stage 1, stage 2, REM, etc"
] |
[
"Can the stomach digest calcium-rich foods such as egg shells, bones, etc and would eating those be beneficial to the human organism?"
] | [
false
] | null | [
"Yeah, definitely. I know of a nutrition professor that highly advocated buying canned salmon ",
" the bones because they aren't super hard and are an excellent source of calcium. ",
"It seems like using eggshells in powder form are useful and can be absorbed as well. I'd assume if you can or...want to even che... | [
"Eggshells commonly have salmonella and other bad bacteria on them though, right? Might be a good reason to avoid eating them without taking proper safety precautions. "
] | [
"Yeah it's definitely more common on the shell than inside. ",
"The CDC says that about 1 in 20000 eggs may be contaminated.",
"That statistic was from the 1990s though, so that could have possibly changed. "
] |
[
"Vacuum Walls as insulation?"
] | [
false
] | Theoretically, wouldn't a wall that was vacuum-sealed be the best possible insulator, because there is no medium (other than the wall) to transfer the heat? | [
"This is how a thermos works."
] | [
"This is what we use to store cryogenic liquids like liquid nitrogen and liquid helium for weeks or months without it all boiling off.",
"The primary method of heat transfer is the thermal radiation traveling from the warm surface to the cold one, and it turns out that this can be drastically reduced by inserting... | [
"http://en.wikipedia.org/wiki/Vacuum_insulated_panel",
"Surprisingly, yes. It's actually structurally feasible using aerogels, which are the usual answer to impossible problems. Unfortunately it costs a lot, can't be cut to size, and deteriorates over time. (Speaking as someone who's pulled water-damaged insulati... |
[
"What determines the placebo for a vaccine's clinical trait?"
] | [
false
] | Why is saline solution the choice of placebo in control groups? What determines it to be used? Are there other placebos and what are differences? | [
"Generally it needs to be:",
"Known to be safe and if a drug, licenced in the area that the trial is taking place. ",
"Able to be made up to be indistinguishable from the trial drug - this is harder than you think: things like colour, consistency and even smell are critical. Without this either the participants... | [
"Especially for Corona Vacs most people get a reaction afterwards (e.g. headache, fever). Saline, etc. does not have it. This significantly reduces the quality of the study because most test persons know if they got the vac or the placebo."
] | [
"It's hard to know for 100% certainty. Placebos can cause psychosomatic symptoms that can present with real physical findings. I wouldn't say that \"most\" test subjects know which one they got."
] |
[
"Does a helium tank get heavier the emptier it gets?"
] | [
false
] | I know that it would get progressively less massive, but would it weigh more on a standard scale as it got empty? | [
"Now a partially filled tank, one that has gaseous helium in it but no liquid, technically would be lighter, but we are splitting hairs at this point :D",
"Just to be clear: it would be lighter than if it had air in it, but not lighter than if it were empty."
] | [
"Now a partially filled tank, one that has gaseous helium in it but no liquid, technically would be lighter, but we are splitting hairs at this point :D",
"Just to be clear: it would be lighter than if it had air in it, but not lighter than if it were empty."
] | [
"If you mean empty by filling in atmospheric air, then yes, it's possible.\nBut! Actual mass is proportional to the particles inside, so if the pressure inside was significantly bigger that the 1 Atm pressure outside, it can actually be lighter when you let it out.",
"\nWiki: \"Helium gas cylinders have the highe... |
[
"Has there been any evidence to suggest that improvements in cellular technology (in terms of quality and quantity) has led to more lives being saved in emergency situations?"
] | [
false
] | I realize that the answer should be an obvious yes, but I was curious what the data actually shows. Has there been a significant improvement in recent decades? | [
"There's a lot of data and research in this area, though it's scattered across a number of different fields depending on the particular kinds of benefits you're after.",
"Some studies have looked at the use of cell phones in ",
"reporting accidents more quickly",
" or being ",
"able to call",
" if you nee... | [
"I'm a 911 dispatcher, and I'm just going to hijack the (currently) #1 comment to add one thing. No matter how good our technology gets, it won't replace the human element. GPS and cell tower triangulation are only so accurate, and even less so inside. If you don't know where you are, the chances of getting help ar... | [
"Isn't this why the fcc recently passed the indoor mandate? ",
"Although, I hear there is a loophole and the carriers can basically do nothing and get away with it, something about how indoor and outdoor locations can be mixed. ",
"I agree, the tech exists, but the indoor solution isn't here yet. "
] |
[
"Are there any practical uses for trying to get a Noble gas to react with other elements/compounds."
] | [
false
] | I know there was an expirament in which Xenon was successfully forced to react. But why? What's the point, an is there any use for this? | [
"You ",
" if there's a use for something or not until you find it and learn about it. Open inquiry is what got you the technological advances you enjoy every day. If it was obvious that studying nature would give us technological improvements that would make life better, then science would've developed a lot earl... | [
"Noble gas compounds have fairly niche uses, in general. Many are very strong oxidising agents and could be quite useful because there's little chance of any side reactions happening - ",
"xenic acid",
" can oxidise other compounds without introducing any impurities into the reaction, since it liberates stable ... | [
"Xenon difluoride is used for aromatic fluorination (this be the overall theme here) as its very handy for this (especially as impurities aren't possible and the Xenon will simple evaporate). (while this is a nice option though this by no means is used large scale it would be far to expensive)",
"Krypton difluori... |
[
"Is the 'radioactive days' real and do explosions on the Sun's surface affect our health?"
] | [
false
] | I've been hearing this for a while in my country. I've even experienced stuff like that. By that I mean headaches on the same days with other people, high blood pressure, etc. I've also heard from many people that it's 'radioactive days', explosions on the Sun burst out huge energy and it does affect our health. Sorry ... | [
"From what you're describing, no.",
"People misunderstand the concept of radiation, but basically there are two categories of things we think of as \"radiation\": electromagnetic waves and energetic particles.",
"EM waves are the same thing as light, and they include radio, microwave, infrared, visible light, ... | [
"One tiny correction to a mostly accurate statement: non-ionizing radiation cannot harm you in the way we think of radiation poisoning/cancer, but it can still give you RF burns."
] | [
"The sun sprays out charged particles, but the Earths magnetic field catches most of that before it reaches the surface.",
"What reaches the surface is mainly induced by cosmic rays - which means from sources outside the solar system."
] |
[
"Is there any way that you could send a signal through space, bounce it off of something, and receive it many years later?"
] | [
false
] | It could be like a radio-time capsule, or more like a delayed back up system. We could transmit as much of our accumulated knowledge as possible, and aim for the signal to return a few thousand (or however long) years later. That way, if there is some catastrophic incident that wipes out most of the population, not onl... | [
"The power required to bounce a wave off an astronomical object thousands of light years away would have to be ",
". Your idea works in principle, but would be extremely hard to put into practice. A better idea might be putting a space probe into a stable but distant position (so whatever wipes us out doesn't get... | [
"Well, if I want to send some sort of signal out there and have it bounce back, I'd want a really good reflector. Otherwise, I'd just get back weak and/or garbled signals, like the difference between standing in front of a mirror and standing in front of a normal wall.",
"I can't think of anything out there that... | [
"Yes, if you could make a whole star go boom."
] |
[
"How can sound waves escape from a black hole of light cannot?"
] | [
false
] | [deleted] | [
"They don't escape from the black hole. It black hole is moving throughout the giant cloud of gas and causes the gas to swirl, and that movement and swirling causes the gas to ripple."
] | [
"I would also think that sound waves could come from the destruction of the star that formed the black hole. When the star collapses, it heats up the gas around it, causing it to explosively expand. So I assume this would produce a pretty loud sound front."
] | [
"Just a quick note: It isn't \"sound\" coming from the black hole. Sound requires a medium to travel through because it works based off of vibrations in molecules. There are many videos on youtube such as \"Sounds of Saturn\", etc. where you can listen to what a planet/celestial object \"sounds\" like. But really, ... |
[
"Are anti-perspirant deodorants harmful to humans in any way?"
] | [
false
] | null | [
"That didn't hold up under further research. Aluminum has nothing to do with Alzheimer's. "
] | [
"That didn't hold up under further research. Aluminum has nothing to do with Alzheimer's. "
] | [
"please dont post nonsense to Askscience"
] |
[
"How do aquatic plants in places like the Chesapeake bay resist algae buildup on themselves?"
] | [
false
] | I was at the bay 2 weeks ago working on a project, and I accidentally left some wire fencing in the water. When I returned a few days ago and took the wire out, there was a huge build up of algae and slimy stuff on it. How do aquatic plants, like eelgrass for example, not get covered in this and die? | [
"Marine biologist here. Submerged aquatic vegetation (SAV) actually has a very hard time dealing with epiphytic algae growing on them, as they are outcompeted for light. This is actually one of the major causes of the loss of SAV beds in many areas, as eutrophication increases the prevalence and growth rate of sa... | [
"Believe it or not, plants wage extremely intense biological warfare. Most plants secrete compounds that are toxic to other plants and organisms, which helps them establish their roots so that they can obtain nutrients. I don't know what type of plant you are referring to, but this can be seen with terrestrial plan... | [
"The presence of aquatic plants is normal, but an overabundance of algae usually is associated with nutrient/fertilizer/organic waste runoff (eutrophication) allowing the faster growing organisms to have large blooms where it could not normally be supported. SAV beds are a very valuable part of the ecosystem: fis... |
[
"Do the shapes on the border of a rectangular voronoi diagram tend to have greater area than the shapes that are not touching the border?"
] | [
false
] | null | [
"Yes and no. Voronoi tessellations are a way to distribute space to a set of points. The border can be arbitrary : if you only have a set of points in 2D, for example, what you have is just a collection of points. Then, if there's no border, the shapes on the outside are infinite in size.",
"If you're taking the ... | [
"For a given point distribution, there should be some statistical relationship between the \"inner point spacing\" and the \"point-edge spacing\". This relationship should directly answer OP's question, in terms of the distribution. I believe this relationship could be determined theoretically, at least for a unifo... | [
"Yeah, I was thinking about doing a Monte Carlo simulation myself and to measure the areas directly, but I'm not so clever with programming. "
] |
[
"Do mirrors have a resolution?"
] | [
false
] | Whats the quality of a mirror I guess I mean, and if the answer is different depending on the mirror, then what would a car mirror's reflection quality be? | [
"As far as I'm aware, the resolution of optical systems is related to the wavelength of light, so the smallest features that can be \"displayed\" or reflected are a few hundred nanometers across.",
"It's not unlikely that imperfections in the mirror will reduce this though. In any case, you can't actually ",
" ... | [
"I'll start with the short answer then get into more detail. Since you asked for the quality and resolution I'll try to explain both. I'll then start ranting because there are some very interesting things relating to this. ",
"The short answer is that if your mirror is diffraction limited resolution will be lim... | [
"This is actually a good question. Do the light rays on the mirror have to something like \"bounce off recognisably far from each other\"? I mean, if I for example use some big convex lens to focus the image of my face into a micrometer on the mirror (just >wavelength for the whole face), and then magnify it back, ... |
[
"Does the shape of the end of a pipe affect the fluid dynamics of fluid coming out?"
] | [
false
] | I am wondering if the exit shape of a pipe (cut perpendicular to flow, or angled to stream of flow) affects how smooth a fluid comes out of a pipe. I have an air pipe that carries a material and exits the end. One of the pipes is angled and one is flat at the end and they appear to have different spreading as it exits.... | [
"The longer any section of pipe is in contact with the fluid, the more time the fluid will exert viscous drag on the walls of the pipe. This drag has the effect of slowing the particles nearest to the pipe wall, with a decreasing effect the further the fluid particle is from the wall.",
"This means that any secti... | [
"I was seeing the wider spread on the flat pipe, not angled. There must be something else affecting the stream."
] | [
"In short, yes. It's been a few years since I studied fluid flow through pipes and air flow was not one of the areas we focused on but the outflow from a pipe can be affected by a number of things including the shape of the exit. Sorry I couldn't be more helpful but that is about all I remember from my pipe flow co... |
[
"when I shine a flashlight at Mars, does a small amount of the light actually reach it?"
] | [
false
] | null | [
"Yes, you need to be careful with phrases like \"a small amount\". ",
"Mars is around 225 million km away at ",
" average distance. Lets say you have a 1W flashlight and aim it at Mars, the intensity very far away from this flashlight will drop off as the distance squared (also a little extra from absorption a... | [
"That would be the case for something like a laser, but a flashlight would have a beam wide enough to cover a sufficient swath of the sky to not need such precision. "
] | [
"I would think you would you have to lead the target, to use a hunting term, since Mars is so far away, you'd have to aim the beam to where Mars will be in about 20 minutes. Just thinking aloud."
] |
[
"Why does wearing high-heels increase pressure on one's feet and cause foot problems?"
] | [
false
] | [deleted] | [
"It is very damaging to feet over time, and yes, it does cause foot AND leg problems. The simple fact is that for hours at a time, the foot and its supporting muscles and tendons are forced into a ",
"very unnatural position",
" that is normally reserved for going on tip-toe, something we only do for a few seco... | [
"Also, the angular shape of a heel also can affect the toes, causing ingrown toenails and bunions. ",
"Here",
" is a great image comparing what your foot looks like in heels and in a normally fitted shoe."
] | [
"Good addition and good graphic- thanks."
] |
[
"Do you technically see air? I mean, it looks a lot different than space."
] | [
false
] | Are you technically seeing it, but your so used to looking through it, you don't really think anything of it? Thanks in advance! | [
"This is an interesting question.",
"One of the ways that we \"see\" transparent things is by the way light reflects/refracts through it. For example, have you ever noticed how the angles of things look odd when you're in water? It looks like your leg is at a different angle in the water than it is outside of the... | [
"A better way to frame the question might be to refer to an Earth denuded of atmosphere, or being on the moon. The answer is yes; without the intervening atmosphere, distant objects look much clearer. Look at a distant mountain range and you will see they look blurred and fuzzy due to the photons being diverted som... | [
"Ok, so that answers the refraction part. What about other characteristics like color or clarity? Does space look \"clearer\" than air? Perceptively?"
] |
[
"All of the planets in our system orbit in the same way. What about other solar systems?"
] | [
false
] | All of the planets including the asteroid belt, Kuiper belt, and dwarf planets orbit the sun on the same plane, like a nearly perfect disc going around our star. Is this a Normal thing? Is there any other solar systems out there that orbit in a more chaotic way? | [
"Given the vast number of other planetary systems, it's entirely likely there is at least one planet that is orbiting retrograde compared to the rest. It's incredible unlikely, as it would pretty much have to be a captured rogue planet(oid). Planets and asteroids form out of the planetary disc that will all be rota... | [
"In single star systems it's pretty common. Gravity tends to flatten things out, and angular momentum caused from the original gravitation collapse of dust into a star is what gives all planets their direction they orbit. But they're finding that it's quite possible for there to be say, polar solar planes in binary... | [
"It is normal, but we know examples where the orbital planes are different. ",
"Upsilon Andromedae",
" is an example (that star is visible to the naked eye, by the way)."
] |
[
"How/why does pouring a carbonated drink into ice make the drink lose its fizz?"
] | [
false
] | I have noticed that pouring coke, ginger beer, and pretty much every other carbonated beverage over ice in a glass causes the drink to lose almost all of its fizz. If I make a Moscow Mule with ice, it inevitably ends up flat; without ice, I have no such problem. I've tried pouring the ginger beer slowly into the copp... | [
"Ice that is freshly taken from the freezer has a pretty rough surface. It is rough enough that it provides tons of nucleation sites for the CO2 in the carbonated liquid to come out of solution, much like the mentos do in the coke + mentos demonstrations but to a lesser extent.",
"To reduce the carbonation loss ... | [
"They have the ice laying out of the freezer. So they melt a LITTLE, but still is ice.."
] | [
"Thank you. I wonder how restaurants and bars manage to make carbonated alcoholic drinks over ice without losing the carb. I will try rinsing the ice first from now on."
] |
[
"Why do classical objects behave classically and not quantumly?"
] | [
false
] | Seeing as visibly large objects are a collection of smaller systems that behave quantumly, how come as a whole these large objects do not behave quantumly? | [
"They do. Everything does. The quantum effects are just insignificant compared to the classical effects, which is the average result. Same deal with relativity. Everything experiences the same transformations all the time, it's just below the threshold of being meaningful. "
] | [
"The law of averages. A single coin toss is completely unpredictable. But flip a coin a thousand times and you can make very good predictions on the average outcome.",
"Trying to measure the exact speed and position of tiny particles are like those single coin tosses. The behavior of the large objects comprised o... | [
"Please read our guidelines and FAQ before posting",
"A good example of this is quantum tunneling: A quantum particle has a non-zero probability to go through an energy barrier (a wall) which is higher than the energy of a particle. However, the probability of multiple particle (an object) tunneling at once goes ... |
[
"On the cellular level why does certain foods like black beans and pasta go hard and other foods like bread and apples go moldy?"
] | [
false
] | null | [
"Black beans and pasta are dehydrated."
] | [
"Clearly you have never been a college student. Pasta and beans will mold."
] | [
"mostly depends on the water content"
] |
[
"How true is it that male baldness is inherited from your mother's side?"
] | [
false
] | [deleted] | [
"When a male trait is said to be \"inherited from the mother's side\", what is generally meant is that it's linked to a gene on the X chromosome; because men only get one copy (from their mother), a man with the trait will gave inherited it from his mother. She could have inherited it from either her mother or fath... | [
"Hi MinArbejdsBruger thank you for submitting to ",
"/r/Askscience",
".",
" Please add flair to your post. ",
"Your post will be removed permanently if flair is not added within one hour. You can flair this post by replying to this message with your flair choice. It must be an exact match to one of th... | [
"Male pattern baldness is an X-linked trait, meaning it is found on the X chromosome.",
"An XY male receives one copy of X from his mother and one copy of Y from his father. So a male can get this gene only from his mother (since it's on the X gene, not the Y gene.)",
"An XX female receives one copy of X from ... |
[
"in the FAQ it is stated that one proof of the universe's expansion is that \"more distant galaxies are packed closer together\". What sort of measurements have been made to show this?"
] | [
false
] | null | [
"Telescope observations were done to establish two things. ",
"1) The distance to galaxies using Supernova Light curves and redshifts.",
"2) How seperated the galaxies are (basically galaxies \"per square inch\")",
"Its found that at larger distances, there are more galaxies per unit area at that distance.",... | [
"Exactly, we are not seeing them as they are now, but as they were back then. So we can observe they were closer in the past."
] | [
"Is the reason this tells us its expanding is because the ones farther away are being seen further back in time?"
] |
[
"If I made a giant wheel, and spun it at 100rpm how large would it need to be in order for the outer edge to be traveling at the speed of light?"
] | [
false
] | I am aware that an object this large would start to 'bend' as well, but let's just assume that the object is made out of an unbreakable material and this factor won't come into play. | [
"Relativistic effects aside, let's live a little and consider we are in a Newtonian universe (linear approximation of reality)",
"100rpm is the angular velocity\nrpm = 2",
"pi radians /(60s) = pi radians /(30s)\n100rpm = 100 * pi radians /(30s)",
"speed of light is 299,792,458 m/s",
"relevant angular veloci... | [
"For reference, this is like a planet 91 times larger than Earth (by volume), spinning 144,000 times faster."
] | [
"yes, but you'd have a sweet looking planet from a spaceship's perspective."
] |
[
"If space is essentially a vacuum, how do planets cool off over time? Where does the energy disperse to?"
] | [
false
] | null | [
"More mathy, the ",
"Stefan-Boltzmann Law",
" which describes the radiation heat flux from objects as a function of temperature to the forth power for black bodies. Using the law, you can actually get a decent estimation for the surface temperature of the Sun or the temperature of Tungsten wires in incandescent... | [
"Yep. To be more specific, the energy radiates away into space in the form of photons (electromagnetic radiation). "
] | [
"Yep. To be more specific, the energy radiates away into space in the form of photons (electromagnetic radiation). "
] |
[
"Questions about behavior of electrons in an atom?"
] | [
false
] | Hello I’ve been learning about Quantum Physics recently, it’s super interesting, and it seriously has left me with more questions than answers. Crazy to think that matter is probabilistic on the most fundamental level. I’ve been thinking about some of the features of the quantum mechanical model of the atom for a littl... | [
"The electron isn't really both a particle and a wave, it's really neither. It's a metaphor, really; the wave/particle duality business is just a way of saying that the electron sometimes has behaviour that's a bit like a classical particle, and sometimes has behaviour that looks like a classical wave, but it's not... | [
"Oh wow, thank you so much for such a detailed answer! Really, the first and the last paragraphs really cleared the confusion about when electrons really are, understanding that they’re neither particles nor waves makes so much sense! And I never knew that the clouds are only pictures traced by measuring the positi... | [
"First off, what exactly does it mean for an electron to behave both as a particle and a wave?",
"You are familiar with the idealized concepts of particles and waves. The truth is that electrons (and everything else) displays properties that you would typically associate with particles and properties that you wou... |
[
"What causes someone to talk in their sleep?"
] | [
false
] | null | [
"Somniloquy (Sleep-talking) usually occurs during transitory arousals from NREM sleep, which is when the body does not move smoothly from one stage in NREM sleep to another, and they become partially aroused from sleep. Further it can also occur during REM sleep at which time it represents a motor breakthrough of d... | [
"Follow up; sometimes friends/ girlfriend have reported me humming in my sleep, a high pitched \"hmmmmmm\" with my mouth closed or a more opera-esque \"ahhhhhh\" with my mouth open. Sometimes I can almost be aware of this happening. Is this related to sleep talking, or something else entirely?"
] | [
"What causes sleep talking?",
"You might think that sleep talking occurs during dreaming. But scientists still are not sure if such chatter is linked to nighttime reveries. The talking can occur in any stage of sleep.",
"Sleep talking usually occurs by itself and is most often harmless. However, in some cases, ... |
[
"How do animals with such different evolutionary trees have similar skeletal structures (example: chickens and humans both have a humerus upper arm/wing bone and radius/ulna lower)?"
] | [
false
] | null | [
"Broadly, it seems that the general body plan of chordates (animals with spinal chords) works really well. Having a central spine, four appendages, and a head with a brain in it has led our lineage to a lot of success. As a result, any time in natural history when a mutant was born with an extra set of limbs or a d... | [
"Humans and chickens are on the same evolutionary tree. We share a common ancestor with chickens that already had single bones in their upper limbs and double bones in their lower limbs. This is called homology, anatomical identity by descent.",
"Organisms that evolve anatomical traits independently generally do ... | [
"What do you mean by different? Humans and chickens are both vertebrates. In the broad scheme of things birds and mammals are pretty similar. Arms are switched out for wings, and hair is switched out for feathers"
] |
[
"Say I take a stretched rubber band, clamp it into a vice, and then melt it. What happens to the potential energy?"
] | [
false
] | [deleted] | [
"An elastic band actually doesn't store any potential energy when you stretch it. When you stretch a band, then release it, it relaxes back to its original shape due to entropy. ",
"This",
" explains that process quite well.",
"When you stretch a rubber band, the work you do actually heats up the rubber band ... | [
"Most people don't believe the cool down bit, but here's a cool experiment: Stretch two bands equally. Release one immediatly, and leave the other to cool to room temperature before releasing. The first one will retract far quicker, and releasing the second will cause it to very slowly retract and become noticeably... | [
"When polymers are sufficiently cooled they surpass the \"glass transition temperature\" where the polymer chains that could previously slide other eachother to provide an elastic effect become fixed in a more crystalline structure. It varies between polymers but you could probably find a list of common ones.",
"... |
[
"How realistic, even in theory, is an artificially induced teraforming event? (Think Firstly/Serenity)"
] | [
false
] | Watching all these sci-fi shows, you always hear about humans or other races teraforming a planet to make it suitable for habitation. Assuming a planet was in the habitable zone of its parent star, would even be possible to teraform a planet for human habitation? | [
"It is possible with the proper amount of progress in the genetic modification or chemistry fields. However it would probably be a 100+ year long project, if not thousands of years. It would all depend on the planet we are trying to teraform and its climate/biochemistry. ",
"Edit: As far as the genetic mod. goes,... | [
"Searched",
"Relevant ",
"discussion",
"Original question by ",
"blueatlanta",
"What challenges are we presented with if we were to terraform Venus or Mars?",
"Are there valuable resources from either of these planets?",
"Can we find gems, fuel, undiscovered elements?",
"What is stopping us from pur... | [
"Thanks. Truth be told posting from my phone and the mobile app has a very bad time performing a search. Thanks for the info!"
] |
[
"Are animals capable of having “obscure” dreams? Eg. flying, being a different animal, etc"
] | [
false
] | null | [
"We don't have a way of knowing at the moment"
] | [
"Do we know if they dream the same way humans do? As in, do dogs go through the same type of sleep cycle as humans?"
] | [
"That's a different question. I recommend making a new post for that, although you can find plenty of information about sleep stages in animals with a simple google search and perhaps you should look there first."
] |
[
"Where did the first anaerobic bacteria on earth come from?"
] | [
false
] | I'm reading Origins by Tyson and Goldsmith and the first anaerobic bacteria on Earth are mentioned in the first chapter, but not where they come from. Based on commonly accepted scientific theories, where did these simple anaerobic bacteria come from and how did they end up on Earth? Were these bacteria present in th... | [
"Early life (if not the first life) on Earth would have all been anaerobic due to the lack of oxygen in the Earth atmosphere until roughly 2 billion years ago when oxygen became prominent via production by cyanobacteria which are photosynthetic. ",
"This is called ",
"the Great Oxidation-Event",
" and is rega... | [
"Yes that's true, but I want to know where the bacteria on the meteorite came from"
] | [
"True, but I think you misunderstood OP's question. Now you explained that anaerobic life came first and how it evolved into aerobic life.",
"OP, however, was aiming more in the direction of \"where did the bacteria come from ",
"\", i.e. ",
"abiogenesis",
" (see also ",
"here",
")"
] |
[
"When I push down an air-filled ball in a pool of water, I can feel a lot of energy being built up the deeper it goes. What exactly is happening?"
] | [
false
] | I understand the basics - water is denser than air, so air is trying to float up. I'm kind of amazed at the seemingly huge amount of force that builds up this way though. Why does the amount of potential energy stored in the ball (is it even potential energy exactly?) seem to increase the deeper I try to push the ball ... | [
"That energy turns into increased pressure inside the balloon i think. Good question though."
] | [
"Your observation is true, up until the object is completely submerged as the buoyancy force is proportional to the density of the water and the volume of the object submerged. If you had alot of water and you pushed very deep there might be some force resulting from the density change of the compressing water but... | [
"In fact, the force at 10 ft would likely be less than at 1 ft because the additional water pressure compresses the balloon so it has less volume.",
"This brought up another question in my head. If I was right in my assumption that I'm storing potential energy in the ball by pushing it down, and if that energy de... |
[
"Are cellphones always transmitting signals?"
] | [
false
] | Are cellphones always emitting a wireless transmission to the towers, if so, are the waves "bouncing" or a direct path? And finally, if the theories are true that cellphones cause cancer, if you're inside a mall for example, isn't everybody just in a huge wireless signal mass?. And if the signals do bounce everywhere, ... | [
"They're only in constant contact with a tower when you have an established connection such as an active phone call or data connection. Otherwise, it generally sits idle and occasionally 'polls' to see what's available in the area. The waves' path to the tower is line of sight (although this applies to what microwa... | [
"Good, solid answer but just to add to it there can always be a ",
"multipath propagation",
" where the signal does bounce around and cause inter symbol interference. Frequency division multiplexing helps get around this."
] | [
"Thanks for the answers guys :D"
] |
[
"In this rapidly innovating world, how to scientists stay on the same page?"
] | [
false
] | null | [
"One answer is that we have no perfect system for this. This isn't as much of a problem as it seems, as repetition (or reproduction) is a good thing, in that it confirms the results.",
"We have a few imperfect methods. In order of faster to slower dissemination, they are personal contact, conferences, journal art... | [
"This answer gets to the nub of it.",
"And it's important to highlight that scientists are generally only really up-to-date in whatever tiny subfield they're working on at a time. And even then some of them are not as up to date as they could be.",
"Before you start any experiments you're going to take some tim... | [
"When a research group discovers something new, they'll typically submit a paper to a relevant ",
"academic journal",
" for publication. Other researchers in the field can read these journals to make sure they stay on top of recent findings."
] |
[
"The flu vaccine contains 4 variants. Why do they limit it to only 4 varieties?"
] | [
false
] | null | [
"Influenza is confusing. ",
"Let’s start with the word “variants”. Why are there four variants in the vaccine? Because there are four major influenza subgroups that circulate among humans each year. They are influenza A(H1N1), influenza A(H3N2), and two subsets of influenza B, the Yamagata and the Victoria subse... | [
"Cost and efficacy for the most part.",
"Adding an additional strain increases cost, there was a lot of discussion when the move from a trivalent (three strain) to a quadrivalent (4 strain) vaccine.",
"The health organisations look at strains present in different parts of the world, as well as strains occurrin... | [
"There are a lot of different technical reasons (economics, size of dose, delivery method, risk of complications, supply chain issues) such that each additional strain included in the vaccine has real costs. Thus, designing a vaccine is always a trade-off between cost and benefit.",
"The ",
"CDC does extensive ... |
[
"Why is it that semiconducting materials have lower resistances the hotter they get?"
] | [
false
] | [deleted] | [
"A material that conducts electricity well (a conductor) has lots of charged particles that can move around, allowing electrical current to flow. A material that doesn't conduct electricity (an insulator) has no movable charged particles (either there are no charged particles, or the charged particles are locked in... | [
"Ohhh, that makes sense. Thank you, very well explained!"
] | [
"All of the metal’s outer electrons are already delocalised, they all can already carry charge. Increasing the temperature only increases the rate of vibration of the positive metal ions and electrons, which means there are more frequent collisions, slowing down the flow of charge."
] |
[
"Whats the yellow stuff next to our eyes that's there after we've slept?"
] | [
false
] | And why doesn't it appear during the day? | [
"It's called ",
"rheum",
". When you're awake, you blink, and tears carry it away. When you're asleep, you're not blinking, and it accumulates in the corners of your eye"
] | [
"Sorry, if you follow the wiki through, it's mucus plus skin cells and dust"
] | [
"Oh, ok! Thanks! "
] |
[
"Humans have created so many different plastics and plastic waste, what is the likely-hood that a microbe will adapt and begin eating the plastic waste, and eventually plastic we use on a daily basis? Could this be catastrophic?"
] | [
false
] | null | [
"there already is a fungus that eats plastic. \"Gusse fed chips of phenolic resin to five different species of white-rot fungus to see whether they could eat it. The team found that one species (Phanerochaete chrysosporium) turned from white to pink after a few days, suggesting that it had broken down the resin int... | [
"http://m.gizmodo.com/5880768/amazonian-mushroom-eats-indestructible-plastics"
] | [
"I guess my main question is what are the chances that something like that becomes a serious problem in our daily lives since nearly everything is in some part made of plastic?"
] |
[
"Can the human body survive breathing pure oxygen at lower pressures?"
] | [
false
] | I know that pure oxygen is poisonous at atmospheric pressure, but wasn’t sure about the question in the title. I’m reading the new Artemis book about the moon colony - the book explains they breathe pure oxygen at a lower pressure and I wasn’t sure if it was true, and if it is true, what the difference is that allows p... | [
"Yes, surviving with pure oxygen at low pressure is perfectly feasible. The problem of oxygen toxicity at high pressures was discovered in the late XIX century, and there was much research about this during the first half of the XX century (in the context of divers and submarines) and at the beginning of the space ... | [
"Why are you using Roman numerals in 2017?"
] | [
"Roman numerals are often used to label centuries in Romance languages (e.g., the beer Dos Equis means two X and celebrate s the beginning of the XX century when it was founded). Judging by OP's history, they speak a Romance language or two."
] |
[
"Why can the nerves in limbs be reattached and still function but not the spinal cord?"
] | [
false
] | It is possible for surgeons to reattach severed limbs and have them recover functionality. What is physically different about the spinal cord that makes it impossible to successfully reattach like can be done with the nerves in arms and legs? | [
"As you can imagine, the spinal cord is an extremely complex bundling of neurons that interconnect with every nerve in your body. It's simply too difficult to identify and re-connect each nerve to where it originally was prior to the injury. Additionally, injuries that typically occur in the spinal cord are often d... | [
"How do you reconnect a nerve anyway? Just push them together and hope for the best? Glue? "
] | [
"Its usually done by physically sewing the nerves back together. The surgeons will often use the assistance of microscopic cameras and robotics to help ensure maximum precision."
] |
[
"What would the result be of 2 identical AIs played chess?"
] | [
false
] | null | [
"Google's ",
", trained solely by reinforcement learning from\ngames of self-play, took 4 hours to beat the previous world champion chess program, Stockfish 8. ",
"Paper",
". (PDF)"
] | [
"Most likely a draw, as is the most likely outcome whenever two strong engines or players play one another. Keep in mind that chess is not a perfectly balanced game, White has an advantage in going first. Black simply replicating all of White moves will not go well, so you will not see an engine playing the identic... | [
"And AlphaZero as well.",
"Many draws with some wins, the stronger the AI is the larger the fraction of draws tends to get."
] |
[
"Does the human body use stored (old) fat or newly digested fat for energy first?"
] | [
false
] | [deleted] | [
"Not quite right. Fats, especially triglycerides are hydrolyzed into fatty acid monomers in the GI tract, remade into triglycerides in your enterocytes, and packaged into chylomicrons for transport to the liver. "
] | [
"Newly digested fats go to liver before being stored. If your body then needs energy (this generally means your creatine phosphate and glycogen stores are depleted), the liver will use the recently digesed fatty acids since they are more available (adipose fats are less available because a catabolic hormone has to ... | [
"If you mean fat straight out of the stomach, that fat is not digested. In order to get those huge fat molecules into your bloodsteam, your digestive system has to break the fat down into sugar in a similar process to when you burn fat. The sugar, now moved into your blood from your intestines, can be used immediat... |
[
"Do fetuses sleep?"
] | [
false
] | null | [
"Yes, that is ",
"when sleep develops",
"."
] | [
"Only read the abstract, but this bit \"There is evidence for episodes of wakefulness in the fetus. \" made me wonder whether the baseline pre-36 week, pre-organization of behavioral modes state is most similar to sleep? If so, have there been EEG studies in preterm infants that early or perhaps in utero that would... | [
"Yes they do, I am speaking as a mother of 3, so slightly layman, (apologies mods) but in utero babies often get into a cycle of waking and sleeping as indicated by the amount of activity felt. The cycle changes at different stages in the 2nd and 3rd trimesters, but often they baby follows the same wake/sleep patte... |
[
"Why has bad eyesight not been 'evolved out'?"
] | [
false
] | I read but it didn't really answer my question, which is why do so many people need glasses to see even reasonably well? Surely this would be selected against by natural selection? I understand the argument that people in the distant past didn't live long enough for age-related myopia to kick in but I know many people ... | [
"Evolution doesn't lead to perfection. If you can see well enough to eat, not get eaten, and fuck something, your genes get passed down.",
"Also, there could be recessive genes for myoia that are leading to two healthy parents having a myopic child. Your question is no different from any other question about how ... | [
"\"Survival of the fit enough.\"?"
] | [
"Stephen Jay Gould suggested \"Survival of the barely adequate\"."
] |
[
"What could be causing purple smoke seen in the photos of the Tianjin blast?"
] | [
false
] | [deleted] | [
"Potassium. Probably from potassium nitrate, a common oxidizing agent used in munitions. The violet color is from the atomic emission of potassium. like this: ",
"http://fineartamerica.com/featured/potassium-flame-test-andrew-lambert-photography.html"
] | [
"\"The White Helmets @SyriaCivilDef: (...) barrel bomb doesn't explode, then leaks gas which discolors the soil. Ideas? 1/3\" ",
"https://twitter.com/SyriaCivilDef/status/577191496627175424/photo/1",
"\nThe White Helmets @SyriaCivilDef · 15 mrt.",
"\nThis from barrel bomb in Hayyan - 5-10kms from Hreitan, s... | [
"\"The White Helmets @SyriaCivilDef: (...) barrel bomb doesn't explode, then leaks gas which discolors the soil. Ideas? 1/3\" ",
"https://twitter.com/SyriaCivilDef/status/577191496627175424/photo/1",
"\nThe White Helmets @SyriaCivilDef · 15 mrt.",
"\nThis from barrel bomb in Hayyan - 5-10kms from Hreitan, s... |
[
"How does the 2nd law of entropy apply to an emulsion?"
] | [
false
] | [deleted] | [
"It does seem that way macroscopically! Droplets of oil will coalesce until you have a water-only phase and an oil-only phase, which looks more ordered.",
"This doesn't look like such a paradox at the microscopic scale. A water-only phase will form an extended hydrogen bonding network, like ",
"this",
". Oil ... | [
"It requires energy to break hydrogen bonds, so forming emulsions don't \"release energy\", as the user said, but it ",
" absorb energy."
] | [
"Great answer. Now I have always been fascinated by the apparent violation of the second law that happens in miso soup, where if you stir it up, after a while all the particles will gather in the middle of the bowl. Not sure what is going on there. Here's an ",
"exaple",
" which kinda shows it, but it stopped t... |
[
"Is my Y chromosome identical to my dad's?"
] | [
false
] | I was reading on and I came across , and I was wondering whether it was real. | [
"Well, the part about the Y is true, it's the same as your dads Y* and that is that same as his dads Y* andsoforth. ",
"In this statement he/she is wrong: \"So you don't know whether your X chromosome comes from, but you know where your Y chromosome comes from, and therefore you know that you share no genetics wi... | [
"Yes!"
] | [
"So would this imply that all males have the exact same (baring mutation) Y chromosome in common? Couldn't you trace back (way, WAY back) to a common ancestor?"
] |
[
"Why must a runner go for long distances to increase their endurance?"
] | [
false
] | I have no solid points against a buddy of mine. He argues that he can train just as well through 4 minute stints of running his hardest (I think it works something like 20 seconds 100%, 10 seconds rest, repeat for 4 minutes) as I can by running for 45 minutes at a time - assuming we do this equally as often. He keeps b... | [
"If you want a place to start reading, ",
"here",
" is a reasonably comprehensive literature review.",
"The single most important factor in distance running is how much oxygen can be taken from the air and delivered to mitochondria in the muscles. There are lots of other factors (removing waste products, stru... | [
"VO2 Max is a confusing concept that's been consistently misused by coaches and sports scientists for decades. Oxygen transported to the mitochondria is what matters most, VO2 also includes oxygen that never gets to the mitochondria, but is instead used to clean up waste. Two people with identical VO2 might be tota... | [
"It's called high-intensity interval training. Tabata method, specifically."
] |
[
"How long would a scent last in a glass jar?"
] | [
false
] | Could it last forever? | [
"If you had a vessel that could be sealed and would not allow any exchange of material between the internal and external environments, and didn't absorb or react with any of whatever molecules that produced the scent, then the only thing that would limit how long the scent remained would be the rate of decay of the... | [
"Butyryl chloride, which hydrolyses in air to butyric acid (the essence of rancid butter, or, a month of non-shower)."
] | [
"Its highly improbably, if not impossible, that any complex, scent-producing molecule would last forever",
"What if you froze it to near absolute zero?"
] |
[
"Is there any difference in getting vitamins and minerals from a multivitamin as opposed to actual food?"
] | [
false
] | For example, could one live a healthy lifestyle by eating a a good mixture of whatever fats, carbohydrates, and proteins they prefer plus a multivitamin? | [
"One possible difference is something called bioavailability. This is a measure of how effective your body is at absorbing the nutrients (vitamins, protein, whatever). Some sources have better bioavailability than others. E.G. milk has excellent bioavailability for protein and calcium."
] | [
"Just the normal vitamins are the same in pills and in fruits/veggies. What you won't get with vitamin pills are any other, possibly not-yet-identified potentially good ingredients that are in fruits and veggies. It's quite a limited number of substances that are supplemented through vitamin pills, so it's a lot be... | [
"Im not an expert but as someone who is into fitness and according to my pediatrician, multivitamins don't really serve purpose to the general healthy population. It typically is most useful for people deficient in certain nutrients"
] |
[
"Do human beings refrain from inbreeding because of an evolutionary trait OR because it is not socially accepted in society?"
] | [
false
] | null | [
"Yes.",
"The social taboo developed in response to evolved mechanisms to prevent inbreeding. Both act in concert to prevent it in modern humans."
] | [
"Humans have a genetic predisposition to avoid mating with people they knew as children. Even people who know they are unrelated are less likely to become romantically involved if they spent time together as children, it's called the Westermarck Effect. ",
"http://en.wikipedia.org/wiki/Westermarck_effect"
] | [
"Sometimes I really wonder how much of what we do today in society is just some evolutionary behavior that's manifested in that particular way."
] |
[
"Why/how does fire create light?"
] | [
false
] | What exactly causes fire to emit light? | [
"It's a mixture of atomic/molecular excitations and thermal radiation. In short, gaseous atoms and molecules will become less excited by emitting light. These emissions will result in ",
"discrete peaks in the spectrum.",
" Incomplete combustion which creates soot will glow incandescently, this is thermal black... | [
"Whenever a charge changes states or its motion, it must produce a self propagating \"disturbance\" in the electromagnetic field. This happens because changes in the EM field do not travel at infinite speed.",
"These disturbances are light. ",
"When you shake a fan, a wave of wind is produced. Same idea, witho... | [
"...My head hurts. ELI5?"
] |
[
"A question about centrifugal force in a weightless environment?"
] | [
false
] | After reading 'Rendezvous with Rama' by Arthur C Clarke, I have been stumped by a thought about centrifugal force in a weightless environment. In the book a character attempts to fly in a winged craft along the central axis of a massive closed spinning cylinder with a gaseous environment. As they go along (If I am reme... | [
"If you are not in contact with the wall of the cylinder at all and it starts to spin, you won't suddenly feel a centrifugal force pushing you outwards in your frame of reference.",
"However if you hold onto the side of the cylinder while it spins up, your rest frame is now non-inertial. And now there ",
" a ce... | [
"In that scenario the skybike fell because the atmosphere of Rama rotated with the structure of the vehicle. As soon as the aircraft started to break up, it got pulled around with the atmosphere, which introduced centrifugal force and created pseudogravity, so it fell and crashed.",
"Great book. If you are intere... | [
"The centrifugal force is only acting on you if you're holding onto the wall. The reason that you fall down when you jump is because the cylinder is curved.",
"Take a look at ",
"this animation",
", which shows a red ball being thrown in a rotating environment. You can see that after it's thrown, no force act... |
[
"Why do men seem to want to do more sexually or physically than women?"
] | [
false
] | [deleted] | [
"Can you give a reliable source for that?"
] | [
"Libido tends to be linked to androgen levels, especially testosterone. These are generally higher in men than in women."
] | [
"That is not always true. Women can have just as high a sex drive as men, we just tend not to act on it as often as men."
] |
[
"Do animals know when to stop eating or eat less since their prey can't reproduce quick enough?"
] | [
false
] | We have a lot of trouble with overfishing the ocean for example. so I asked myself If animals may have such a problem as well and stop before it's too late. | [
"Starvation culls predator numbers when prey are in decline, when there is a glut of food then the population increases with it, when the prey are scarce the predators decline. ",
"There was a study done on rabbits and foxes and the population numbers of both fluctuate in very similar trends over time, with the p... | [
"Question is not about feeling full but being aware of prey population declining meaning less food food in the future"
] | [
"Why are you asking me. I was notifying you of your misperception of the question. I doubt they do as well."
] |
[
"Evolution of defensive poisons"
] | [
false
] | How can a defensive poison (such as that of a poisonous frog) evolve if the selective pressure depends on its predator knowing it's poisonous? That is there no advantage to the individual to being poisonous if you die anyway. Is that why poisonous animals are colourful, because only the distinctive ones are remembere... | [
"A frog can have a hundred matured offspring before it gets eaten, and so can they, in turn. This would give time for the whole process to take place. The mutation does not necessarily die with the eaten frog. I hope I did not misunderstand your statement."
] | [
"The selective pressure doesn't depend on the predator knowing it's poisonous. The poison kills the predator, regardless of whether it knows what it ate was good for it or bad for it - however, those predators that don't eat the poisonous prey will live, while those that don't will die. Eventually, you select for... | [
"There is also good documentation on organisms, specifically insects, that produce toxic compounds and are not eaten by larger organisms. This happens because, unlike what you might imagine, the large organism actually \"samples\" the insect before it fully commits to eating it. ",
"For example, if a toxic insect... |
[
"I am NeuroBill. I'm a neuroscientist who had worked Down-under, in Europe and back down-under again. Ask me anything about cellular neuroscience, working in three countries or having two passports!"
] | [
false
] | My name is Dr Bill Connelly. I've been selling my skills as a neuroscientist for a decade. My skill is using an (admittedly old) Nobel prize winning technique to understand the electrical properties of the brain and combining that with computational modelling of these things. I've used what I know to probe the cellular... | [
"What is happening in an ADHD persons brain? And what are the best treatments for ADHD?",
"Thanks! "
] | [
"I can answer some of that! ",
"Regarding what is going on in the brain of someone with ADHD:",
"The brain is... Really ludicrously complex. The tools we have available to us are very limited in their ability to look at the fine details of what's going on in a living human brain. You can do fMRI studies o... | [
"Hello everyone!\nSorry I'm a little late to the party, but they fired this thing up at 1am local time. However, it's 6:44am, the coffee is poured, my beard is oiled and I am ready to answer."
] |
[
"Did this once 50 mile wide sea in north west China (40.5 N,90.84 E) evaporate down in size to become just a salt farm?"
] | [
false
] | I was thinking that it might have seasonal variations that I'm not seeing in | [
"Your link goes to the panama canal. You meant to link this : ",
"https://maps.google.com/maps?oe=UTF-8&q=40.5%20N,90.84%20E",
" .",
"Edit: For a better view of what he is talking about go back and forth between maps and satellite."
] | [
"Thanks, I changed the link"
] | [
"Gogole maps kindly names the nearest town: Ruo Qiang Xian, Bayinguoleng, Xinjiang, China @ 34 km (20 miles?) distance.",
"Putting that into the web produces travel guides that explain the nature of the area",
"http://www.wiki86.com/view/6978.htm",
"http://www.travelchinaguide.com/attraction/xinjiang/korla/lo... |
[
"When a bird returns to its nest and see that either the nest itself or the egg is missing how does it react? Does it realize that it may have been eaten?"
] | [
false
] | I know some birds are surprisingly smart so I just wanted to know how they handle that situation. | [
"Excellent question! I was talking about the same thing because watching a documentary i saw some birds invade nests and place their eggs leaving their babies behind \"for adoption\". It always baffled me that the adoptive parents just accept that. So I don't know if they are not smart on that level or if they just... | [
"I'm fairly certain that on that level of cognition the natural mothering instinct is more powerful than physical recognition. Their brains are just not big enough."
] | [
"This is called brood parasitism. Tricking a different species to raise your own offspring. The cowbird is the textbook case for this behavior, where the chick hatches early and instinctually rolls the competing eggs out of the nest. The reason why the parents don't react is because they recognize their eggs by col... |
[
"What's the smallest change in temperature a human can detect?"
] | [
false
] | null | [
"I can detect milliKelvins using an EPR temperature probe."
] | [
"i think it might depend where on the spectrum between \"hot\" and \"cold\" we're talking. i think it's easier to detect a change in temperature when things are fairly moderate as opposed to if the same amount is changed while it's already either hot or cold while approaching the pain threshold. also it might depen... | [
"I read once that 1 degree Fahrenheit is supposed to be the smallest unit of temperature that a human can detect, but that doesn't seem correct, based on what everfalling mentioned. Maybe it's the smallest unit that can be detected in a reasonable ambient temperature range (-10F - 110F)? "
] |
[
"Different spacetime curvature for different objects?"
] | [
false
] | Spacetime curvature accounts for how stars work as gravitational lenses for light. When explaining gravity as spacetime curvature, does it explain it completely - without the need of additional factors? Imagine shining a light beam vs. throwing an apple on earth? Obviously, there is hardly any curvature affecting the l... | [
"Imagine shining a light beam vs. throwing an apple on earth? Obviously, there is hardly any curvature affecting the light beam, but quite a lot affecting the apple.",
"The difference is that light is moving at ludicrously fast speeds compared to the apple. If you threw the apple at near the speed of light, it w... | [
"It's somewhat technical, but the \"curvature of spacetime\" (the metric) affects the motion of massive particles, massless particles, and tachyons* in three different ways. There's a certain quantity that is equal to 1, 0, or -1 depending on which you're dealing with. The faster objects are moving, the more their... | [
"Since you mentioned tachyons...",
"Are you saying that the trajectory of a tachyon resembles that of light the ",
" it gets, rather than the ",
" it gets, as one might naively assume? "
] |
[
"When recalling a memory, does it make the memory stronger/more imprinted once you remember it or does it actually become more \"used up\" causing each recollection to become distorted each time?"
] | [
false
] | [deleted] | [
"\"There are two main methods of accessing memory: recognition and recall. Recognition is the association of an event or physical object with one previously experienced or encountered, and involves a process of comparison of information with memory, e.g. recognizing a known face, true/false or multiple choice quest... | [
"Rather than try to repeat what they said, I'll give you this instead: ",
"Relevant Radiolab"
] | [
"it is my understanding that you would not \"use up\" a memory in recalling it, at least not in the sense your checking account can be used up by unchecked spending. your memory will not become distorted ",
" from usage. to try to fully answer this question, i would say there are two big possibilities:",
"so wh... |
[
"Why are atoms with too many neutrons radioactive?"
] | [
false
] | I understand that having too little neutrons means the electromagnetic force repelling the protons from each other outweighs the strong nuclear force, but why does having too many neutrons make it unstable? Wouldn't adding neutrons increase the strong nuclear force while the electromagnetic force remains relatively the... | [
"Now, I don't claim to be an expert in nuclear physics, although I did my undergraduate thesis project on a topic in few-nucleon systems, so I'm ",
" sure that what I'm saying here is accurate. If there is a nuclear physicist please correct me if I'm wrong.",
"For systems with few nucleons (say < 6 for the sake... | [
"What about larger atoms? Why are heavier isotopes of mercury unstable?"
] | [
"I always look to the semi empirical mass formula. Increasing the number of neutrons makes the system larger. Nucleons on the surface interact with less nucleons and are thus less bound. So you essentially have a weakening of the strong force. In addition, due to Pauli exclusion, too many neutrons would occupy ... |
[
"Probability question"
] | [
false
] | If there's a 6 sided die, 4 sides with an F and 2 with an M and I roll the die 3 times, am I more likely to get an M on the third try versus the first? | [
"no.",
"Every time you roll the dice you have 33% probability of getting \"M\". The dice don't keep track over how many times you roll, or what you rolled previously. They're just dice. "
] | [
"Suppose that you throw once, decide do go to the toilet and return, then start again and throw twice. Was the last one the second or the third?"
] | [
"Further information for OP / anyone else: this mistake is called the ",
"Gambler's Fallacy",
"."
] |
[
"From my six-year-old: why do roosters crow in the morning?"
] | [
false
] | They crow at other times of course, but I didn't really have a good answer for him. Is it some kind of aggression/dominance behaviour? | [
"Are any lights on? The roosters may be confused by environmental cue."
] | [
"He is six, though. You think he really wants someone talking down to him like he is five?"
] | [
"I used to live in a small town in China where many of my neighbors kept fighting cocks, as well as ordinary domestic chickens. I can attest that those fuckers crowed at any and all times of the day and night. Contrary to what I expected I didn't notice any uptick in crowing frequency at or around dawn. (And I was ... |
[
"How are ribosomal proteins synthesised?"
] | [
false
] | Ribosomes build proteins right? But how are the proteins, that make up the ribosomes built in the first place? Or are ribosomes automatically given to daughter cells? | [
"Ribosomal proteins are manufactured by ribosomes just like every other protein.",
"Ribosomes are indeed inherited by daughter cells from the parent cell."
] | [
"Only the egg. ",
"Source",
", ",
"source",
". "
] | [
"Yep. A daughter cell inherits ribosomes, and then can make their own. Ribosomal proteins aren't special, they're proteins like any other. "
] |
[
"Do computers slow over time, or is an old computer only slow due to increased software resource usage?"
] | [
false
] | Ignoring malware, let's say a PC from '95 was run today on the exact same applications, websites, etc that it was run on in '95. Would it run at the same speeds as it did back then? | [
"The CPU is clocked at the same speed, yes - assuming there have been no changes to any of the software installed on the PC, it should run at the same speed",
"In the more general case, there are mechanisms that cause the maximum speed a CPU could run at to decrease over time - nbti is the biggest contributor and... | [
"What is NBTI?"
] | [
"In general, it would run at the same speed. There are however a handful of things that can make a computer slower (like a higher error rate from various parts, especially a hard drive) which can cause it to redo some work (like re-read a file). But as byrel said, these types of things are far more likely to just r... |
[
"Why are bruised spots on fruit sweeter than the rest of it?"
] | [
false
] | null | [
"Bruising on fruits occurs because parts of the fruit cells' cell wall are ruptured, releasing the enzymes. This causes accelerated ripening, a process that involves breaking down enzymes, but more importantly, hydrolyzes storage polysaccharides. Those polysaccharides convert to smaller sugars (glucose, fructose, s... | [
"Your saliva and digestive enzymes would break down those same starches, so the caloric value should be the same.",
"I would imagine it’s ",
" that other compounds we consider nutrients (vitamins etc) might also be broken down by enzymes in the bruise, but I don’t know for certain. Certainly not enough to impac... | [
"Awesome response- thank you!!!"
] |
[
"Have we contaminated space with life from earth?"
] | [
false
] | For example, do we know if the Voyager probes or the Curiosity rover did not carry (living or dead) bacteria, viruses, or other microorganisms (e.g. tardigrades) into space or other planets? Are there normally steps taken before launch to prevent this? | [
"We almost certainly did include those microbes on Voyager, since cleaning protocols are only used on probes going to places we expect to find life. Since Voyager did not land/crash anywhere, no cleaning.",
"NASA has a protocol for cleaning these probes and rovers and the program is overseen by the ",
"NASA Pl... | [
"Yes. But so has nature. It's likely that some big impacts have thrown Earth rocks into interplanetary space that could still have contained living Earth micro-organisms, and some of those could have landed on other planetary bodies (certainly Mars, possibly the moons of Jupiter and Saturn)."
] | [
"The sun releases a lot of UV radiation that our ozone layer shields, as well as our magnetic field for solar wind.",
"Both are effective methods of destruction of organic molecules.",
"Are organic molecules present on the Voyager? Very likely. Can any self replicate as life does? Likely not."
] |
[
"Why did the Shuttle start to move forward upon takeoff?"
] | [
false
] | I was watching some space stuff and I noticed that the Shuttle moves forward on takeoff. Not as in roll, yaw or pitch, it goes up as it should but goes forward ever so slightly. In the video below, it just goes to the right. (Example - ) What makes this happen? Is it due to the SRBs being more powerful than the Shuttle... | [
"The Space Shuttle Main Engines, attached to the Orbiter, are not directly under the assembled vehicle’s center of mass. As such, the SSMEs are angled to thrust through the center of mass instead of vertically. This keeps the vehicle from pitching nose-down uncontrollably during flight."
] | [
"This is perfect, I didn't know about that angle. Thank you!"
] | [
"They start the Main Engines first to make sure they are spooled up and working before the SRBs are lit. Since, once the SRBs are lit the Shuttle is lifting off one way or another. So what are you are seeing is the the ME thrusting and the Shutting rocking forward and back to vertical from the thrust. Only then ... |
[
"Is there any chance of there being an undiscovered simple machine?"
] | [
false
] | null | [
"Well - I'd say there are perhaps some chances as we work out the basics of nanotech. Some of those microminiaturised machines might exploit some small-scale properties of matter which are irrelevant at the macro scale."
] | [
"If you're asking whether there is a probability greater than 0, the answer is, \"Of course!\" For a long time we believed we had all the components necessary for a basic electronic circuit, then in 2008 HP created the ",
"Memristor",
", which was a fundamental circuit element that had not existed except in th... | [
"I think that means HP invented it. I can talk about the general concept of a machine that uses ice cream as fuel and spits out gold bullion, but nothing has really been invented until there's a working device."
] |
[
"Why were the cameras on the Voyager 1 turned off?"
] | [
false
] | I was reading an article and read they were turned off as it heads into the unknown. | [
"Because everyone bullies NASA for their lunch money :( "
] | [
"what if there was something to see?",
"What if there's something interesting to detect, but only if we turn off the camera to power the probe long enough to detect it? NASA isn't turning off the cameras because they're giving up, they want to make the most of limited resources."
] | [
"Nothing to see, and Voyager has a limited amount of power and data storage. Additionally it'll get harder and harder to continue transmitting images as it gets farther away from Earth. "
] |
[
"could you drink some sort of ATP liquid for calories?"
] | [
false
] | What would your digestive system do with it? | [
"You certainly can drink ATP.",
"I include that link only to show that oral ATP supplements are available. I would be very hesitant to make any claims on what (if any) effects these supplements would have.",
"In my opinion, your body would digest the ATP and use it for its component parts as it does with all f... | [
"I think It would break down immediately in your saliva since it's not too stable in water. It might produce a strange sensation on the tongue in doing so. "
] | [
"Good point. I think that's why they gave it an enteric coating in the study cited."
] |
[
"Did Bipedal Dinosaurs Hop?"
] | [
false
] | null | [
"From what can be guessed from the fossil record and their characteristics, it's very unlikely they could, hopping as a whole is a very energy inefficient system of movement, and presents a huge stress on leg muscles and bones",
"Small birds can get away with hopping, as their mass is negligible, and their legs v... | [
"I watched a nature show recently that stated the kangaroo leg tendon is springy. This allows energy reuse while hopping. I believe they claimed the resulting hopping was more energy efficient than human running. "
] | [
"There's not any good evidence to support the idea. We have quite a few trackways showing dinosaurs running with a typical alternating stride, but there are only a handful of trackways that could potentially be interpreted as those of a hopping dinosaur, and consensus is that those were made by other animals (in t... |
[
"Largest Possible Atom?"
] | [
false
] | [deleted] | [
"We don't know!",
"There are two limiting scenarios, the atomic one and the nuclear one. The atomic limit, somewhere between 137 and 179 (sometimes called \"Feynmanium\" is the point the ionization energy of an electron is equivalent to its rest-mass energy, so if you ionize the atom it can create another electro... | [
"Depending on whether you allow gravitational binding, you might consider a neutron star to be a single enormous atom. The size limit would then be Chandrasekhar's Limit, the mass at which the neutron star would collapse into a black hole."
] | [
"*Nuclear force (or residual strong force), not electromagnetic. The electromagnetic force actually destabilizes nuclei with protons in them, because it'll push them apart. Neutrons are neutral and don't really interact with the electromagnetic force anyway."
] |
[
"Is there any scientific reasoning behind the fact that momentum is the derivative of kinetic energy with respect to velocity?"
] | [
false
] | Is this just a sort of mathematical coincidence or are the principles of one's momentum and kinetic energy intertwined? | [
"It is definitely not a mathematical coincidence. When a body is being accelerated its gaining kinetic energy according to:",
"dE=Fdx=vdp. If we assume m is constant then we can do the following:",
"dE=vd(mv)=mvdv=pdv, and therefore dE/dv=p. ",
"Most modern physicists prefer to express KE as p",
" /2m b... | [
"This is only true for a free particle; introducing a potential which depends on the generalized coordinates or velocities will alter the definition of the generalized momentum"
] | [
"In the ",
"Lagrangian formulation",
" of Newtonian mechanics this is more or less the ",
" of momentum.",
"In fact you can define \"generalized momenta\" in this way; for example the derivative of the kinetic energy with respect to the angular velocity is the angular momentum."
] |
[
"[Mathematics] The l_2 norm can be defined in a basis independent fashion, can other l_p norms be defined in this way?"
] | [
false
] | So I have a question I think I should've known from basic courses, but now I can't seem to find an answer anywhere. Say you have a vector space V, and assume that it is an inner product space (which for any physically meaningful situation I guess one can give V this structure). Then, the l_2 norm can be defined via the... | [
"The important thing is that Lp-norms are only valid on function spaces, and in finite dimensions function spaces are very closely related to bases. In fact, choosing a basis for a finite dimensional vector space V is equivalent to choosing an isomorphism between V and the vector space of functions from {1,...,n}->... | [
"The Lp-norm is only defined on the function space, and on the function space it is basis independent, since it is just an integral on those functions. If V is a random finite dimensional vector space and R",
" is the set of functions from a finite set X to the reals, then an isomorphism V->R",
" will pullback ... | [
"Hi thanks!",
"So I'm definitely staying within finite dimensional vector spaces. I still don't really see why these norms are basis independent though. I'm familiar with the fact that a vector space together with a choice of basis (indexed by X for example) is isomorphic to the space of functions over X. Then th... |
[
"At what point can we no longer notice a difference in monitor refresh rate?"
] | [
false
] | [deleted] | [
"Ahhhh, this is tricky for lots of interesting reasons.",
"First off I'm going to go on a slight tangent and talk about g-sync (et al) and the heritage of monitor signaling standards going back to CRTs. You see, with a CRT the image was displayed by sweeping several electron beams across the display, lighting up ... | [
"A great write up! To me, this question is a rephrase of '",
"'. That would set the theoretical limit, and ",
"this graph shows",
" that most young adults seem to be able to discern ~15 ms (66Hz) temporal gaps. The extreme end are able to discern 5ms or less (200Hz+) temporal gaps.",
"Now, identifying tempo... | [
"100ms is only 10hz, and even 10ms is only 100hz, so it's likely that refresh rates higher than 100hz are not useful for humans in terms of perceived input/response latency.",
"For latency, yes, but when you have 100ms to determine if the guy peeking around the corner is running, walking, or stopped, the more fra... |
[
"Why don't our teeth heal?"
] | [
false
] | Why do we need fillings for our cavities, after all shouldn't evolution have caused that our teeth can regenerate like our bones and skin? Idk if this is the same but; We see this by some rodents who's ameloblasts don't die after their teeth grow. Though they need to constantly gnaw at things, to keep their teeth at th... | [
"For the purposes of evolution the most important thing was that we lived long enough to pass on our genes. Our teeth generally last long enough to accomplish this goal and likely would have lasted longer before humans started consuming soda and candy."
] | [
"So your teeth do repair themselves. Only very slightly. Teeth can \"last\" until people are 60 and older without brushing their teeth or taking care of them. The main reason our teeth get broken down so fast is the high sugar foods and other weird bad for your teeth foods we eat. If we ate a diet closer to what ca... | [
"But damage to your teeth like smashing them against rocks and stuff? Being able to repair your teeth would have been a huge advantage, no? Or was it just so rare that there was no evolutionary pressure?"
] |
[
"What is a good metric to identify the \"uniformity\" of a distribution?"
] | [
false
] | [deleted] | [
"Entropy is nice if you can be sure that your distribution is continuous. Piecewise uniform distributions also maximize entropy.",
"I haven't done this personally but my gut feeling is that I would go with a simple error norm between the (unique) uniform distribution function on a certain domain and your measured... | [
"Echoing the conclusion of ",
"/u/theBB",
", look elsewhere.",
"If I may make an alternative suggestion, why not find the discrete fourier transform of your data, normalize the energy to one, and then find the energy in the DC component? This would be akin to considering all data to to be constant, and the va... | [
"I think calculating the mean temperature and then finding the root mean square error about that mean should work pretty well. ",
"https://en.wikipedia.org/wiki/Mean_squared_error"
] |
[
"Theoretical Question about subatomic particles. The thought came to me when pondering solar system formation..."
] | [
false
] | We know matter is made up of atoms which are revolving around one another's subatomic forces. Just like gravity is draws together dust in the vacuum of space. Some particles obey gravity and some do not. So we're thinking there's an even smaller particle which for some reason defines gravity. Wouldn't it be safe to ass... | [
"This might be a lost cause, but here goes...",
"We know matter is made up of atoms which are revolving around one another's subatomic forces. ",
"Subatomic particles like electrons \"orbit\" protons and neutrons in some sense...",
"Just like gravity is draws together dust in the vacuum of space. Some particl... | [
"Some particles obey gravity and some do not",
"Not true.",
"Anyway, there's no evidence to suggest that quarks and other particles have internal structure or sub-particles. There was evidence to suggest the same of protons and neutrons before quarks were discovered. Some people call the hypothetical particles ... | [
"I was under the impression neutrinos disregard other matter and just pass right through. That led me to think they're unaffected by gravity too, or well, massless. The more I think about it the less that makes sense. So they just have extremely minuscule mass?"
] |
[
"Question about spinning spacecraft to produce artificial gravity. Does running backward make you lighter?"
] | [
false
] | So in the movie The Martian (or 2001 A Space Odyssey), they employ large spinning spacecraft to produce artificial gravity. My question is this: if you run/jog in one direction would you get heavier and if you run/jog the other direction would you get lighter and actually float if you match the speed of the rotation? I... | [
"I answered a similar question ",
"here",
"."
] | [
"Jumping would certainly mean that the ground is no longer exerting a force on you, so, yes, in that sense you \"cancel out gravity\". But you have a tangential component of velocity, relative to some non-rotating reference frame when you jump up. There are no external forces on you, so your linear momentum is cons... | [
"Awesome! Thanks for the answer! It looks like my intuition was correct. ",
"I wonder if with the 70 foot radius station you could reach 14.5m/s because as you get lighter you would be able to devote more energy to accelerating?"
] |
[
"What would be the effect of removing mosquitoes from the ecosystem?"
] | [
false
] | CDC said that there have been >100 instances of Zika in the U.S. so far, which reminded me that there is a company, Oxitec, which has been marketing that would eliminate mosquito populations through breeding in areas prone to mosquito-borne illnesses. Is anybody familiar with the outcomes/results of these efforts to da... | [
"Unfortunately it isn't really clear what the effect would be, and I believe the prevailing opinion right now is that it would be better to err on the side of caution by controlling their numbers rather than to eradicate them completely. Zika virus spreads via the mosquito species ",
"Aedes aegypti",
" and ",
... | [
"thank you for the very informed response."
] | [
"Excellent explanation. I was just going to go with the classic 'We can't predict what will happen, so let's not completely wipe them out yet' method."
] |
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