title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"How in the name of physics can ice cubes form these upside-down icicles in my freezer?"
] | [
false
] | It simply blew my mind when I opened my freezer door to see two upside-down icicles. I've seen them do this more since but this is by far the tallest I've seen them get. Can AskScience explain this to me? | [
"This",
" page at caltech.edu has a nice explanation of ice spikes."
] | [
"These are called ",
"ice spikes",
".",
"The basic idea is that water expands when it freezes, so if the top starts to freeze first the water underneath gets displaced. But the only direction it can go is up, so it does so at the weakest spot in the surface ice (or an opening if the surface isn't freezing uni... | [
"Wikipedia could certainly use an update from that page."
] |
[
"Are modern, engineered cigarettes MORE harmful or addictive than the relatively unprocessed tobacco of our ancestors."
] | [
false
] | Saw the top comment on this video, and I got curious. So far, everything seems to lead me to: 1. Smoking is bad. Let's not discuss this further. 2. Unsubstantiated forum posts Help me find some evidence! | [
"I worked at a cigarette factory for a few years. I'm not sure of the status of my nda, but basically most of the stuff they add is food products. Most of that is casing to make it able to be cut (otherwise it would turn to dust). The flavoring is a tiny percentage of the final product. ",
"That being said they ... | [
"There are more than 100 additives, and upwards of 599 in some cigarettes. To, and I quote ",
"camouflage the odor of environmental tobacco smoke emitted from cigarettes, enhance or maintain nicotine delivery, could increase the addictiveness of cigarettes, and mask symptoms and illnesses associated with smoking ... | [
"In direct studies of formation of precancerous cells in lab animals, HUGE doses of nicotine over LONG periods of time have no effect when nicotine is delivered in isolation. When nicotine is delivered in tobacco, there are huge effects. I feel quite safe in stating the existing scientific literature supports e-cig... |
[
"How much of the proteome and genome do we understand?"
] | [
false
] | I was just wondering about the overall set of knowledge humanity has and the equestion just popped into my head. In terms of percentage what's the rough guesstimate of how much we understand of the fields as a whole? What are the benefits of each field of research? ( Potential benefits too) and what do we have to look ... | [
"In terms of percentage what's the rough guesstimate of how much we understand of the fields as a whole?",
"Not much. As a wildly optimistic esitmate, I'd put it in the single digit percentages. We don't know all the players, nor do we know how all the players interact.",
"We've sequenced the genome, but we sti... | [
"The genome is well on its way to confusing us for another few decades, and the proteome is just beginning to go from cool sounding to confusing. ",
"That said, there are a few things we do know.",
"1) ",
" (and by proxy, the \"exome\") of the human genome. On the other hand, we have no idea what a lot of it ... | [
"None of it, or more precisely, next to nothing.",
"This question is way too broad to get a meaningful answer as it depends on how you define \"understand\". It also sounds like you are holding a philosophical assumption that knowledge is finite, which many (most?) philosophers of science do not believe to be tr... |
[
"Has there been any study on the life span of the higgs boson and gravity?"
] | [
false
] | Pretty much, the more mass around it and its life span? | [
"It is still too early to know much of anything about the Higgs Boson. The physicists at CERN are now entering the characterization phase of a new particle where they create more particles, and carefully watch the results to figure out the characteristics of the new particle. Once they have the Higgs Boson characte... | [
"What do you mean?"
] | [
"There is an AMA about this exact question in ",
"/r/IAMA"
] |
[
"Which biotechnological barriers are currently preventing drug barons from genetically engineering potatoes that produce cocaine?"
] | [
false
] | null | [
"lol",
"The short answer is that there are no technical barriers to doing this. Others in this thread have speculated that the import of an entire biosynthetic pathway might impair the host or cause other difficulties, but in fact this kind of thing is the bread and butter of we metabolic engineers, and the tech... | [
"Yes, but the plant will only grow in Colombia and Bolivia, which is a bit of a drawback because those countries are pretty poor. You want to sell it to rich people, which means you have to cross a border with the stuff. This causes troubles. But if I have a herd of cows that give coca-milk, I can produce my cocain... | [
"Yes, but the plant will only grow in Colombia and Bolivia, which is a bit of a drawback because those countries are pretty poor. You want to sell it to rich people, which means you have to cross a border with the stuff. This causes troubles. But if I have a herd of cows that give coca-milk, I can produce my cocain... |
[
"When two balls are released on a Newton's Cradle, why is the momentum transferred to the two at the end and not just one (giving it a greater speed)?"
] | [
false
] | null | [
"That would conserve the momentum term, however halving the initial mass while doubling the initial velocity gives the kinetic energy at the other end of the cradle as KE = 1/2",
"m)",
"v)",
" which comes out to KE =mv",
" or double what the initial kinetic energy was.",
"The only mass/velocity combinatio... | [
"What if the balls at the other end had a different mass?"
] | [
"What if the balls at the other end had a different mass?"
] |
[
"If the visible light spectrum follows a straight line from ~400nm (red) to ~800nm (violet), how can it be represented as a color wheel?"
] | [
false
] | Related: How is purple a combination of blue and red, if purple and blue are on one side of the spectrum, while red is at the other side? | [
"Color is created by your brain by using three sets of cells called \"cones\" on your retina, which have response peaks that correspond to red, green, and blue.",
"Also it's worth mentioning that the primary colors are different if you're dealing with light (red/green/blue, all colors mix to form white), or pigme... | [
"It should be pointed out that the word \"purple\" refers to colors that do not lie on the color spectrum. The color that appears on one end of the color spectrum is called \"violet\" in the scientific literature, and the word \"purple\" is used exclusively to refer to non-spectral colors."
] | [
"Color perception more about your eyes than it is about the spectrum.",
"The human eye has three color receptors...when the eye says \"red and blue receptors are firing, green is not\" the brains translates that as \"purple\". That's why color charts can be multi-dimensional...it is all about the interaction of ... |
[
"How do my eyes \"know\" the difference between viewing a small screen close-up compared to a big screen from further away?"
] | [
false
] | In other words, why is the visual effect of watching a movie on a theater screen significantly different than watching on a TV screen, assuming both screens appear the same size in my field of vision? | [
"There are at least two ways. First of all, your eyes must turn inward slightly in order to both face the same part of the same object. To converge on a nearer surface they must turn inward slightly more, and to converge on a more distant surface, they must turn inward slightly less. Secondly, the muscles that s... | [
"theatre pixel resolution is usually a LOT bigger than tv pixel resolution.",
"(I think it's in the 4000s, but this is just going from memory.)"
] | [
"Like any object you view (not just screens), your question is explained by what is called depth perception",
"http://en.wikipedia.org/wiki/Depth_perception",
"I haven't been here a very long time. Is it bad just to post a wiki link? Am I supposed to provide a more 'plain english' explanation?",
"Interestingl... |
[
"How do you calculate pressure at which a supported plate would break?"
] | [
false
] | null | [
"There are approximate analytical solutions for thin flat plates loaded by pressure, but finite element analysis is the quickest method for thick ones with odd boundary conditions, especially when using brittle (less forgiving) materials.",
"If you specify the materials to be used, the maximum expected pressure, ... | [
"With a viewing aperture only 1/8\" across, it shouldn't require a particularly thick piece of window material.",
"I need the following pieces of data:"
] | [
"I don't know of a seal rated for 30,000 psi. A typical O-ring is rated only for about 3000 psi.",
"However, a high-durometer silicone O-ring should work at 6000 psi as long as the geometry is designed such that the pressure closes the gap through which an O-ring would extrude. This is easy to achieve for the s... |
[
"Does Polynomial interpolation work with n-1 times the same supporting point xi and 1 thats different?"
] | [
false
] | first, english is not my mother language... so dont hate me too much. So when i do polynomial interpolation, and i have n different supporting points, i can build a lagrange polynom(Li(x)) and do the standard interpolation fn(x) = sum(f(xi) *Li(x)) and if i have 1 supporting point, I could simply do a taylor approxima... | [
"I'm not entirely clear what you're asking, but it sounds like you're generally asking why use a lagrange polynomial versus a Taylor expansion?",
"First, they solve different problems. With Lagrange polynomials, you know the value at discrete points, and you want to ",
", that is find the value ",
" those dis... | [
"ok, sorry my technical english is a bit rusty,\nthx for your answer one more question, ist the hermite interpolation basecly just a finite taylor expansion?"
] | [
"ist the hermite interpolation basecly just a finite taylor expansion?",
"I was going to mention that. It's not really a Taylor expansion because it requires values and their derivatives at two distinct points, whereas a Taylor expansion is about a single point. And it's not a lagrange interpolating polynomial ei... |
[
"When an atoms electron drops an orbital and the atom shoots out a photon with momentum p, does the atom then have a momentum of -p?"
] | [
false
] | [deleted] | [
"Yes."
] | [
"Yes indeed, it's called \"radiation recoil\"."
] | [
"p = mv only applies to a nonrelativistic particle. In general, momentum is a property of any particle which is moving, whether or not it has mass."
] |
[
"Are a butterfly and a caterpillar the same animal genetically?"
] | [
false
] | How can an organism achieve such a drastic transformation using the same genome? Does a caterpillar's DNA undergo a rewrite when it metamorphoses? Is there some sort of inherent gene editing going on? | [
"They have the same genome yes. And it shouldn't be that surprising, the same genome that produces your eye is the same genome which produces your kidneys, two very different organs. One of the biggest discoveries from the human genome project was that the absolute number of genes is not that high, it's the regulat... | [
"You would be interested in epigenetics. Your genome is essentially a textbook of instructions for building proteins, but in these instructions you have regulatory parts. Some parts are locked off in some organs, after all there's no need for your eye to tell cells to create all the cell transporter proteins that ... | [
"Can you explain regulation of expression further? I'm interested in how the genetic instructions translate to specific functions."
] |
[
"How do IR detection cards work?"
] | [
false
] | I recently saw this vid: . And it showcased an infrared detection card, which seemed like magic to me. How do they work? | [
"The reason these cards are surprising is that most of the time, when a photon interacts with matter it emits photons that are the same energy or lower -- that means you can't directly make visible light from infrared.",
"There are two types of infrared detection cards.",
"The most common type, the one shown at... | [
"Thanks for the thorough explanation"
] | [
"While gold is a good IR reflector, in order to shift the wavelength it would likely need to be at the nanoparticle level which would be quite ineffective. The manufacturer of some IR cards states that it is made from plastic and liquid crystals, but that's all the info I could get easily."
] |
[
"How do ionic solids like salt melt?"
] | [
false
] | NaCl is held together by an ionic bond. When in a solid, these molecules make a lattice of ionic bonds to stay together. So as I see it, a grain of salt would be a neatly ordered lattice of Na and Cl ions in a 1:1 ratio. Now when the solid is heated to the melting point, why do the NaCl molecules stay intact and just s... | [
"The solution structure of ionic liquids is an active area of research. Evidence suggests a variety of intermolecular forces play a role, explaining the variability in electronic, ionic, and thermal conductivities seen experimentally."
] | [
"Actually, liquid salts usually are ionic liquids and consist of disassociated cations and anions that move about independently. There will still be some order insofar as arrangements where you have a large cluster of (positive) cations or (negative) anions are both energetically and entropically unfavourable and t... | [
"The NaCl molecule is held together by the electrostatic force produced by the oppositely charged ions. As I understood the molecules are held together by forces of attraction which form a lattice network. The only thing I can think of is that the electro static force is far stronger than the forces of attraction b... |
[
"Can someone help clarify electric vehicles?"
] | [
false
] | null | [
"Another genuine problem with this is, what are they going to do with the batteries when they are no good anymore? This is no widely known way to salvage the innards of a lithium ion battery. They can replace the insides, but still need to dispose of whats used. There have been studies on the environmental impact o... | [
"Another genuine problem with this is, what are they going to do with the batteries when they are no good anymore? This is no widely known way to salvage the innards of a lithium ion battery. They can replace the insides, but still need to dispose of whats used. There have been studies on the environmental impact o... | [
"Trying to measure a hybrid or electric car's environmental impact is tough. I've seen articles (link below) that claim the Toyota Prius is worse than a Hummer H3, due to the sheer amount of energy to make the car (mining in Canada, processing in Indonesia, packaging in China, installation in Japan).",
"http://ww... |
[
"Why can we not accept the null hypothesis if p>=0.95 but we can accept the alternative hypothesis if p<=0.05?"
] | [
false
] | Let's say we obtain a p<=0.05. We can say we reject the null and now accept the alternative hypothesis as reasonable. But why can we accept the alternative but not accept the null if we obtain p>=0.95? It seems by accepting the alternative hypothesis we are committing the same fallacy than if we accept the null. | [
"Um. I think you're thinking about P-values incorrectly. If P > 0.05 then you fail to reject the null hypothesis. Frequentest statistics are based on the assumptions of refutationism. This assumes that you can only prove things WRONG by providing refuting evidence. The null hypothesis is the hypothesis that the... | [
"To keep it simple, p values are used to reject a null hypothesis, namely that two samples are from the same population. Take two samples, find their p value and if it is less than 0.05, then you'd say they are, with statistical significance, NOT from the same population (you'd reject the null hypothesis that they... | [
"The difference lies in the definition of p-value, and the reason why we accept or reject the null hypothesis.",
"The level of acceptance/rejection, aka the threshold of p-value, refers to the type-1 error of the experiment, which is defined as the probability that you reject a null hypothesis given that it is in... |
[
"Does your DNA alter throughout your lifetime?"
] | [
false
] | Does everything you come in contact with in your life alter your DNA chemistry in any way? All of your experiences? All of your emotions? Physical damage? Healthy or poor eating? Hygiene? UPDATE: All of this is amazing you guys. I appreciate all of the effort you all put in to explaining. It’s truly amazing; the human ... | [
"By and large your cells are doing their level best to prevent your day to day experiences from having any impact on your DNA. Just about all chemicals you ingest/inhale from whatever sources (food stuffs, drugs, smoke, oxygen, bacteria) will have some impact on your cell's DNA. Plus some other sources of damage su... | [
"There is also a relatively new science called epigenetics. This science looks at alterations to epigenes, which don't ",
" but they do ",
" So your DNA may contain a sequence to make you susceptible to infection; as a child the epigenes keep this sequence suppressed, then when you turn 40 your epigenes change ... | [
"That’s amazing. Thank you so much."
] |
[
"Does focusing our eyes affect the our eye’s “refresh rate”?"
] | [
false
] | null | [
"Maybe ",
"this",
". Which is actually an online book. You can find chapters on the right-hand side."
] | [
"The resolution of your eye, light sensitivity, and motion sensitivity is not uniform across the retina. The periphery of the retina is more sensitive to light and motion but has lower resolution. That's why it is easier to see stars out of the corner of your eye at night than looking directly at them. "
] | [
"Very cool!! Do you have any papers on this to recommend? :) thanks btw!"
] |
[
"Are humans allergic to mosquito saliva? If so, does that favor mosquitoes somehow?"
] | [
false
] | Layman here, who hates mosquitoes with a passion. Yesterday I stumbled upon a factoid picture that says humans are allergic to mosquito saliva and that's why we get red spots. Does that somehow make the mosquitoes' jobs easier? | [
"I believe it's because of the body's immune response which creates histamine. I, too, have been a buffet for hundreds of mosquitoes. Mosquitoes also have an anesthetic in their saliva. The effectiveness of that anesthetic seems to vary because sometimes I feel the bites and smash the bugs while other times I do... | [
"Two reasons for the swelling:\n1. Mosquitos secrete anti-bloodclotting factors that allow it to fully extract a blood meal without the host immune system stopping it in its tracks. These factors will sort of bump around and eventually \"stick\" to host antibodies that will create an immune response with either his... | [
"I don't think it makes their job easier; in fact I don't think it affects their job at all, seeing how the itching usually starts a short while after the mosquito has finished feeding and flies off. Most mosquito bites aren't noticed by the victim at all while the mosquito's there, partly because they inject an an... |
[
"What pattern would a flat mosquito net have in order to be as material-efficient as possible?"
] | [
false
] | I tried to solve this on my own, but I don't even know where to start... It doesn't matter if the final result is impractical to build or if it requires the wires to be cut into smaller portions. Pretend that the material used in this case is so expensive that every femtogram spared is worth the effort. Also, to simpli... | [
"I haven't come up with an answer, but I've got a few extra questions that might help you out.",
"I'll make some additional simplifying assumptions: ",
"Assume the net must cover a bounded (finite), flat region in space, for example a doorway or tent entrance.",
"Assume the wires are rigid, so we don't have t... | [
"That... that was incredibly useful! And for some reason it only appeared today in my inbox. This said, I can't complain!",
"Again, this was all beautifully said, and I don't see why it classifies as speculation (especially in regards to the second more \"interesting\" question, which is exactly what I was lookin... | [
"Would it be possible to determine a formula that would allow to find the right orientation in an any given shape?",
"For a general shape, I suspect not. Consider a rectangle and suppose the parallel lines solution is right. Then add a bump to one of the sides, with the bump much bigger than r, but much smaller t... |
[
"Why does it require so much data to process a photo of a black hole?"
] | [
false
] | So, I don’t understand why you need 7,000 petabytes of data (approximately) to take a photo of a black hole. Can someone explain? | [
"A number of factors come into play here. ",
"Some more detail here: ",
"https://www.livescience.com/65203-black-hole-why-so-long.html"
] | [
"Because it's not actually a photo. The input was never pixels, they are too small to tell left from right directly. All the telescopes put together are just seeing a single point of light each. They need to correlate them together, to see when each wave hits different telescopes to try and figure out where each pa... | [
"Thank you very much"
] |
[
"Is there a condition where a person doesn't get excited about anything?"
] | [
false
] | null | [
"Major Depressive Disorder... Anhedonia, or a general disinterest in things that used to give you pleasure, is a characteristic symptom.",
"Being bummed out can also have a similar impact. Doesn't need a fancy name."
] | [
"I am not bummed out or depressed or anything, I just can't find anything to make me say wow - its the same with hobbies too; I can't find anything that I am crazy about."
] | [
"Maybe you need to find something that challenges you optimally, gets you into ",
"flow."
] |
[
"100% this is a scientific experiment"
] | [
false
] | null | [
"Rememberful"
] | [
"Rememberful"
] | [
"rememberable"
] |
[
"Are several copies of the same memory stored in the brain?"
] | [
false
] | Is there just one single copy, or are there several. If so, are they all stored in the same hemisphere? | [
"Memories, contrary to popular belief, does not work like a video record. There are, in effect, no \"copies\" of memories at all.",
"The brain is a cluster of neurons, roughly 100-150 billion neurons, or that is the estimate (to put that into context, that is a higher number than there are stars in our milky way)... | [
"Ok. This thing with \"therapists bringing out memories that have been suppressed\" is usually, in most cases, a matter of the therapist unknowingly suggesting things to a receptive patient, and thus bringing about the recollection of false memories. As I say, memory is extremely fallible, and it's SUPER easy to in... | [
"I'm sorry if I sound patronizing, but you sound like you're not very familiar with the brain as an organ. The brain is in essence nothing but a cluster of neurons. Everything we do, translates from a pattern of firing in our brains.",
"So, memory is still just a pattern of firing, even though that pattern has gr... |
[
"Is it theoretically possible to surround the sun with solar panels and “harness” the sun?"
] | [
false
] | null | [
"There's a thought experiment, called a ",
"Dyson Sphere",
" (after physicist Freeman Dyson who popularized the thought experiment), that does this.",
"The engineering required to achieve this is far beyond our current capabilities, making it a highly theoretical concept."
] | [
"From what I understand, the Dyson Swarm is a better and more realistic alternative.",
"Edit: yes, Swarm, not sphere again :P"
] | [
"automated self-replicating factories",
"What could possibly go wrong?"
] |
[
"Why do tattoos on the inside of your lip fade, while ones on external skin stay permanent?"
] | [
false
] | null | [
"Would this be because of constant contact with moisture? I would like to know as well.."
] | [
"If I had to guess, I would think it's because the inside of your mouth replaces cells at a much faster rate, therefore the ink would be pushed to the surface much faster."
] | [
"I tried finding a 'scientific' explanation and the best I could get was that the tattoo doesn't go as deep as others, and hence can wear out as the skin regenerates.",
"For three years, though? Anyone? "
] |
[
"Red light interferes the least with night vision right? So why do automobile dashboards always use blue/green/white variations?"
] | [
false
] | [deleted] | [
"I imagine it's a negligible effect compared to the headlights of other cars, so people go with more aesthetically pleasing lighting."
] | [
"They don't always. My car has red lighting (Audi)."
] | [
"My 1970 Dodge Challenger R/T had orange dash lighting."
] |
[
"Would this homemade volcanic fog filter work to reduce sulfuric acid in the air - bubbling household air through a solution of baking soda?"
] | [
false
] | I live in Hawaii and we have problems with volcanic fog (vog). The vog causes numerous health problems which seem to come mainly from the sulfur dioxide content of the vog. The sulfur dioxide turns to sulfuric acid on contact with moist air or moist lungs. I had this idea to use a blower fan to suck household air throu... | [
"It sounds like this would work. Note that baking soda is not technically a base. I think it is a buffer or a salt. (I don't know if it is an alkaline or not).",
"Sodium hydrogen carbonate (NaHCO3) breaks down with any acid HX to make H2CO3 + NaX. H2CO3 (carbonic acid) then decomposes to make H2O and CO2. As lo... | [
"The problem is that you could have large bubble of gas still that contain sulfur dioxide. I don't know how you mix the gas bubbles thoroughly with the baking soda water. I would think that someone has invented something like this already, given that it seems to be a problem where you live."
] | [
"You could use a diffuser, which is a bunch of tiny holes in the downstem (pipe going into the water). Just like a bong!",
"Or you could pipe the gas to the bottom of the solution's container, fill the container with something to break up bubbles (like glass pieces) and let the bubbles break up as they flow past... |
[
"Why; a coffee cup with a little milk in it froze in my fridge but the container of milk next to it was still fluid?"
] | [
false
] | something about the way different materials radiate away and conduct heat; but i would have guessed that it would have come to some equilibrium; all materials arriving at the same temperature in their own time. ~help me science!!! | [
"Over time you are right, but over a short time in a fridge I wouldn't expect things to get all the way to equilibrium. Because of that we need to consider items starting at different temps, tons of different materials with different thermal conductivities and heat capacities, and more.",
"In your particular cas... | [
"The milk has a significant amount of dissolved sugars, proteins, and minerals which together will lower the freezing point compared to water. This is a phenomenon called freezing point depression. If the coffee wasn't sweetened this could explain the difference "
] | [
"interesting things to think about and explore further. thanks."
] |
[
"Is there a \"natural\" way that the human body wakes itself up in the morning? If so, does drinking coffee in the morning lessen the effect of that process?"
] | [
false
] | [deleted] | [
"Your body has a circadian rhythm and wakes itself up at a certain hour. Your body temperature rises, various hormones are released or stopped, particularly the sleep related hormone melatonin which is controlled by the Suprachiasmatic nucleus and to a lesser degree blue light. It's not secreted during your day cyc... | [
"Excluding environmental stimuli (e.g., light), the transition from sleep to wakefulness in the morning is due to two physiological process.",
"One is the ",
"circadian rhythm",
", which promotes wake during the daytime and promotes sleep at night. The circadian drive for wakefulness typically begins to incre... | [
"They did compare caffeinated coffee to decaf, so it's probably the caffeine. But I don't know enough about the process of decaffeination to say whether it significantly changes the chemical composition of the coffee with regards to things other than caffeine."
] |
[
"If muscles shiver for warmth, and the heart is a muscle, why doesn't it shiver?"
] | [
false
] | Or does it under extreme cold temperatures? | [
"Skeletal muscle (the muscles attached to your bones that allow you to move) are the ones that shiver. The heart and other organs like those in your digestive system are a different type of muscle (smooth muscle) and are controlled by separate portions of the nervous system (sympathetic and parasympathetic nervous ... | [
"Thank you very much! Very informative!"
] | [
"The tongue doesn't shiver either."
] |
[
"What causes the observed interaction between matter and a vacuum?"
] | [
false
] | [deleted] | [
"Thanks for the reply. I still don't quite understand though, what kind of forces are acting on matter around a vacuum?"
] | [
"Thanks for the reply. I still don't quite understand though, what kind of forces are acting on matter around a vacuum?"
] | [
"Atmospheric pressure. The weight of the air creates a certain pressure at sea level. When you have a perfectly closed container, there would be no interaction, but once you open it the surrounding atmospheric pressure starts rushing in. It's very similar to opening an empty container underwater, just that you're i... |
[
"Is there any sound in nature that can cause deafness in humans?"
] | [
false
] | I mean something naturally occurring that would be on the decibel level of a jet, concert or explosion. | [
"You would need a sound at 140 dB or higher in order to cause instant irrevocable hearing loss (not necessarily deafness). The blue whale can generate sounds up to 188 dB. When Krakatoa exploded, it made a 180 dB sound. Meteors and eathquakes can generate even louder sounds. "
] | [
"You would have to be unreasonably close to those things for that to happen though, correct? IE that close to Krakatoa and you are dead anyway."
] | [
"Excellent point. "
] |
[
"When will Iceland split because of the movement of the Eurasian Plate and the North American Plate?"
] | [
false
] | null | [
"Iceland is constantly expanding due to the expansion of the ",
"Mid-Atlantic Ridge",
". This expansion, in conjunction with the ",
"Iceland hotspot",
", manifests as a ",
"large number of volcanoes",
". New land is constantly being formed by volcanoes, so as long as the Iceland hotspot remains over thi... | [
"So Iceland is actually getting bigger over time due to the movement of the plates? "
] | [
"Yes. The island is gettin ",
"about an inch (2.5 cm) wider each year",
", not to mention the ",
"new islands",
" that occasionally form."
] |
[
"What is the limiting factor on how fast I can tap my finger on my desk?"
] | [
false
] | When I try to tap my finger on my desk as fast as possible I can't go any faster than 4 or 5 beats per second. Is it my muscles, my brain or something else that won't let me change the direction of movement any faster? | [
"The guy in that video is tapping with his whole hand though and only using the relatively slow movement of his fingers to change which keys the movement of his hand causes him to hit. When I only move my index finger and keep the rest of my hand still, the fastest I can tap is 8 times per second. If I move my whol... | [
"The guy in that video is tapping with his whole hand though and only using the relatively slow movement of his fingers to change which keys the movement of his hand causes him to hit. When I only move my index finger and keep the rest of my hand still, the fastest I can tap is 8 times per second. If I move my whol... | [
"You can hook yourself to a car battery and see how fast your muscle can expand and contract.",
"Won't work. It's a direct current so your muscles will only contract and stay that way.",
"Also, don't do it anyway."
] |
[
"Is string theory an actual scientific theory?"
] | [
false
] | [deleted] | [
"Dude, sure it is. It's still in its nascent stages, but it's certainly a valid physics theory just like any other. One problem is that we haven't fully formulated the theory, so many of its predictions are still ambiguous. But the main problem is that its predictions require energies far greater than those we can ... | [
"I submit to you the following article, published in Physics Today, written by a string theorist:",
"Article"
] | [
"From what I understand the only concepts in String Theory that are falsifiable are shared by general quantum mechanics, Lorentz invariance and General Relativity.",
"Claiming String Theory is falsifiable because of that foundation sounds like bullshit to me, if you cannot test the unique aspects of String Theor... |
[
"As the universe expands, will the fundamental forces change such that matter cannot exist?"
] | [
false
] | [deleted] | [
"We don't think the fundamental forces will ever change. We do like to think that they are all the same force at certain high energy levels but that isn't proved for gravity. Regardless no change.",
"You may be thinking of the Big Freeze or Big Rip theories for the end of the universe. It is noteworthy to poin... | [
"We do like to think that they are all the same force at certain high energy levels but that isn't proved for gravity.",
"It should be noted that it has been experimentally observed only for two out of four forces. "
] | [
"However, our data on the curvature and makeup in the universe seem to strongly suggest one of these two \"fates\""
] |
[
"When we see the night sky, we're basically looking at the stars that are on the opposite side of the sun at a moment in the year. Are modern telescopes able to see the stars that we can't see during the day? Has the sun been an obstacle to observing a specific area of outer space within our range?"
] | [
false
] | null | [
"I don't quite get what you mean... the earth spins on its axis and goes around the sun at the same time, so you can be on one \"side\" of the sun facing away and then, half a year later, on the other side facing the other way..."
] | [
"Thanks, I know this and agree with you, added some text in order to make my question a bit clearer."
] | [
"I guess the answer is no then. The galactic core obscures part of the milky way for us... but there's no equivalent for the sun because in 6 month's time you will find yourself on the other side"
] |
[
"What actually happens when I lower the volume in my smartphone using the volume slider?"
] | [
false
] | And further, if my device is connected to a Bluetooth speaker, what is the correlation between the volume control from my phone, and the physical volume control on the speaker? Are they actually performing the same operation, or can I get a lot more volume steps using controls on both the devices? | [
"In both cases, the smartphone contains a digital signal (the audio) and information about the volume setting, both of which are transmitted to an audio controller, which drives a digital-to-analog converter, which drives a speaker.",
"In the case of playing through wired analog speakers or earphones, all of that... | [
"When you lower the volume on your smartphone, pretty self explanatory hehe, uhm, the screen picks up the signal and cpu calculates and lowers the volume, aka the amplitude decreases. If you connect to the bluetooth speaker, it is different, your phone sends bluetooth signal to speaker and telling speaker to decrea... | [
"That explains a lot. Thanks. "
] |
[
"Why doesn't neutron reflection cause a fission reaction?"
] | [
false
] | So I just stumbled upon the "Demon core" story about the plutonium core going critical via neutron reflection. I was wondering though, why didn't the core undergo a fission reaction when the tungsten carbide bricks were placed around it? Wouldn't it just take 1 single neutron bouncing off the shielding to collide with ... | [
"A single neutron can only fission at most one atom, releasing a tiny bit of energy. If the neutron splits an atom then more neutrons are released. What happens then depends on the geometry.",
"If - on average - the neutrons from one fission reaction produce more than one fission reaction you get a chain reaction... | [
"Wouldn't it just take 1 single neutron bouncing off the shielding to collide with the mass and cause it to go into fission? To my understanding that's how the atomic bombs in Nagasaki and Hiroshima were detonated.",
"No, these are not initiated with one single neutron. There are ",
" fission reactions occurrin... | [
"It is, very fortunately, not so easy to sustain a supercritical configuration of fissile material long enough to release nuclear-bomb-level amounts of energy. Otherwise we would not have (relatively) safe nuclear power but nuclear ",
" would be everywhere. The demon core underwent a \"criticality excursion\", th... |
[
"Pterosaur flight?"
] | [
false
] | [deleted] | [
"That depends on how high a bar you want to set for proof. They have all the proper adaptions for flight: wings for a start, hollow bones, strong muscles for flapping (even stronger for taking off is a recent discovery). Computer simulations with reasonable assumptions show them capable of it. Is that proof? It's a... | [
"I guess my main problem is that after reading a few papers on it, very few of the paleontologists are agreeing on the weight of the animals. Take quetzalcoatlus for example, (I know, the largest of them all is not really the best example) I have seen weight's ranging from 80kg to 200kg. So, how much of the compute... | [
"Here are a couple links to previous discussions: ",
"Demonstration of how pterosaurs might have taken flight",
" ",
"AMA from a dinosaur paleontologist"
] |
[
"What exactly is meant by \"quantum information cannot be destroyed\"?"
] | [
false
] | null | [
"if you knew every piece of quantum information there is to know, you should be able to perfectly reconstruct the entire history of the universe",
"How do you reconcile this statement with the fact that the mathematics of quantum physics is non-deterministic?"
] | [
"if you knew every piece of quantum information there is to know, you should be able to perfectly reconstruct the entire history of the universe",
"How do you reconcile this statement with the fact that the mathematics of quantum physics is non-deterministic?"
] | [
"Quantum information can only be rearranged. This is due to the time parity of quantum physics. The physics has to be the same if time were to play backwards (need other parities too). With classical physics, there is no time reversal symmetry. Information can simply be lost (to heat, sound, etc.) in classical phys... |
[
"flair:Physics If colliding matter and antimatter can annihilate each other to produce a photon, how is momentum conserved when photons are massless?"
] | [
false
] | Or is conservation of momentum a special case of conservation of energy which doesn't always apply? Bonus question: it occurs to me that a massless particle could have momentum if it had infinite velocity; is it fair to say that at the speed of light, time is effectively stopped, so from the photon's frame of referen... | [
"Photons still have momentum, despite not having mass. In fact, all their energy is due to momentum. Momentum=mass x velocity is just a low velocity approximation that breaks down in relativistic cases."
] | [
"Additionally, when a particle anti-particle pair annihilate they produce two photons (at least). A single photon alone could not conserve 4-momentum of the two particle system."
] | [
"Because the full equation isn't E=mc",
" but e",
"In the case with photons, you need relativistic physics as Newtonian formulas start to breakdown. In this case, the energy is entirely conserved through the momentum , p, of the massless photons because when mass is zero, the equation simplifies to E=PC where p... |
[
"How did Einstein go from the equivalence principle to gravity being the curvature of spacetime?"
] | [
false
] | [deleted] | [
"So, the equivalence principle implies that tidal forces are the true signature of gravitation (not free-fall.) In terms of spacetime geometry, these forces can be understood as following from a lack of distant teleparalleism (geodesics not remaining parallel) in turn resulting from curvature."
] | [
"Because the EP says that the local effects of a gravitational field cannot be distinguished from an accelerating frame, i.e. just an artifact of choosing a particular coordinate system in spacetime, and not a real physical effect. The real physical effects of gravitation are nonlocal - tidal forces. These cause ... | [
"Because the EP says that the local effects of a gravitational field cannot be distinguished from an accelerating frame, i.e. just an artifact of choosing a particular coordinate system in spacetime, and not a real physical effect. The real physical effects of gravitation are nonlocal - tidal forces. These cause ... |
[
"How is \"you only dream of people you've met in life before, and your mind can't make up new people\" even testable? Is this really true?"
] | [
false
] | null | [
"This is a common, but annoying, claim. There's no way of testing its veracity, for several reasons.",
"First, the question is ill-posed: what does \"make up new people\" mean? If a person is composed of pieces of others, then do they qualify as \"new\"? In any case, that's not an accurate representation of how m... | [
"Where did you ever hear of such a statement being advocated? "
] | [
"I've seen it trending around -- usually on \"random fact\" lists. I've even seen it on a list from the front page of reddit. Unfortunately I can't find the link though."
] |
[
"What is the difference between soap, detergent, and other cleaning products such as citrus oil?"
] | [
false
] | What does each one do on a molecular level to dirt, grease, microbes? Bonus question: how does each one react to greater/lesser concentration, agitation, contact time? I.E, when are you better off letting something soak vs scrubbing harder vs. using a stronger solution? | [
"Both soaps and detergents are ",
", molecules that have both a water-hating (hydrophobic) and a water-loving (hydrophilic) portion. Both clean the same way: when they contact a piece of grease, the grease becomes attracted to the hydrophobic part, detaches from wherever it is, and can float off into the water b... | [
"Oh yeah, about citrus oil. It by itself does not dissolve in water. So the idea is that it will simply contact that piece of grease and dissolve it. Sometimes it is mixed with soaps/detergents and water to form an ",
", like salad dressing. This basically works like the soaps do."
] | [
"Although soap and detergent kind of do the same thing (removing non polar substances and particles), they are made with different materials and processes, and therefore they have different chemical formulas and purposes. Detergent is much stronger and better at collecting substances than soap, and most detergents ... |
[
"How do bugs survive winter by hiding in tiny cracks, when big animals like us are so vulnerable to it?"
] | [
false
] | null | [
"They are poikilotherm, they just don't die as easily when their body temperature drops, and if they have this kind of behavior, they are pretty adapted to cold weather or high temperature changes. \n Also, small bodies are way way way easier to heat up after getting cold. If you are a bear and you body temperature... | [
"I'm an insect scientist. We do use the word poikilotherm to apply to invertebrates. What it means more specifically is that the animal's body is built to tolerate different temperatures. The opposite is a homeotherm, which can only operate so long as its body stays within a certain narrow range (humans are in this... | [
"A lot of cold-blooded animals like insects and amphibians in colder climates create a sort of anti-freeze when they go in to hibernation. This allows them to essentially stop their body processes until it warms back up again. Cold-adapted animals also have modified protein structures that allow their bodily functi... |
[
"What exactly happens when you delete a file on your computer?"
] | [
false
] | Let's say you have a simple text file with a paragraph on it that you want to delete - what exactly happens to it once it's "permanently" deleted? Is it ever fully removed from the hard drive? If not, does it go anywhere on the computer? Also, what sort of processes happen when a computer deletes a file? | [
"The inode (metadata block where the file's description is stored) is removed from the filesystem's btree (database of all files on the disk) and all disk blocks that were identified as belonging to the inode are marked as empty.",
"Other than that, nothing happens. The file's information is not overwritten (unle... | [
"The file's information is not overwritten (unless you select \"Secure Delete\" of some kind). Technically, the file's data is still exactly where it was but it is ignored by the system and may be overwritten whenever the system next needs disk space since the file's former location is now viewed as \"empty\".",
... | [
"Probably, but there is a chance that the deleted data is not used during the defragmentation, specially if you also deleted lots of other files."
] |
[
"How much force does it require to snap wood?"
] | [
false
] | So I'm a mathematics student trying to help out my younger brother build a bridge for a high school project and I can't find any formulas online to help with this quetsion. I'm sure there has got to be a formula along the lines of Length*Width*Height*constant for specific wood*torque > 0 But I cannot find it anywhere! ... | [
"It's a fairly complicated problem that depends on the shape of the wood (known as the second moment of inertia) and how it's being bent. The simplest case would be a piece of wood fastened on one end, held horizontal, and weighted on the other. From this you can calculate the strain, and compare it to the breaking... | [
"Not a civil engineer here, but I am a Mechanical. The best way to have a beam resist pure bending is to have as much material on the outside of the profile as possible, as the top and bottom edges are under the most stress, that is why I-beams have very little in the middle of the beam and the most at the extremes... | [
"Okay honestly that went way over my head. I sort of understand what it's getting at but I don't think I'll be able to calculate it. It's rather frustrating as it seems to me like it should be a pretty simple calculation.",
"If I had a piece of say 1x1x10cm wood at a 60degree angle to the horizontal then placing ... |
[
"Do bacteria have a meaningful \"top\" and \"bottom\"?"
] | [
false
] | That is to say, if I had a tiny spatula and flipped over some bacteria, would it continue about as it was before, or would it reorient itself back to its previous bearings? | [
"Well, this is an interesting question. At the size scale of bacteria, gravity has a much less drastic effect on organisms—the fluid that the bacteria is in exerts much more of an effect on the bacteria. So \"up\" and \"down\" as we know it, defined by our relation with gravity, isn't really a way that bacteria ori... | [
"Well, this is an interesting question.",
"That's exactly what I said!",
"From the world of infectious bacteria (my field of expertise), there is also another directional consideration: some of these bacteria will attach to host cells. For example, certain types of bacteria use active mechanisms to attach to th... | [
"Well said! Very interesting, thank you very much."
] |
[
"What force causes the Earth's tectonic plates to move?"
] | [
false
] | Additionally, how can this force be so consistent in vector that events like a megathrust earthquake occur? | [
"Ultimately there are two possible causes of why plates move and it is not yet known which is the correct mechanism:",
"1) Slab pull: In this scenario the down going slab pulls the rest of it along and thus causes movement including mantle convection.",
"2) The mantle is convecting due to a temperature gradient... | [
"It's been awhile but the estimates I recall seeing are that slab pull dominates. There's also 'ridge push' but it's pretty nominal. Not quite sure what the OP is on about with the second question. Changes in plate driving forces happen over a much longer time scale the the buildup for stresses that cause earthquak... | [
"No arguments from me. I haven't looked at this stuff for maybe 20 years and so I'm not sure if there have been any more advancements but I'm guessing not. :-) Kind of reminds me of a comment a prof of mine once made. He was going to write a paper with the world's shortest abstract. The title was \"What have we le... |
[
"Why does ice melt slower in water with a higher salt concentration?"
] | [
false
] | null | [
"I assume you're asking about this:",
"http://en.wikipedia.org/wiki/Freezing-point_depression"
] | [
"The water is colder. "
] | [
"I'm confused. You mean vs water of a lower salt concentration? It shouldn't melt slower either. Assuming both waters are the same temperature, the total kinetic energy is higher in the high concentration water."
] |
[
"Can you compress a gas into a solid?"
] | [
false
] | null | [
"Most of the time, no. If you compress it AND drop the temperature, then yes, almost all gases will form a solid at some point.",
"The reason a thing is a gas is becuase it has enough energy to overcome the molecules attraction to one another. This attraction is fairly weak for things that are gases at room tempe... | [
"Wow, I love the graphs! Thanks!"
] | [
"Yes, but you have to have the right gas and then the right conditions. I assume you are asking about a gas going directly to a solid, because going gas->liquid->solid is the trivial answer. Take a look at this ",
"phase diagram for CO2",
".",
"If you take CO2 from the pink area directly to the blue/purple ar... |
[
"Ask Science Scientists: When you review papers do you review anonymously, or do you sign off?"
] | [
false
] | A little while ago I decided I would sign all of my reviews and did so. Of course, now I'm giving a somewhat unfavorable review to someone who might be considered a giant in my field. It's not a good paper, but I might want to work with this person later on on a different project and I'm a bit worried that this might... | [
"I write reviews assuming they could figure out who I am but usually dont actually sign. Best of both worlds- keeps me honest but dont have to worry about fragile egos. "
] | [
"The editors know who I am but the journals I have done this for use a double blind. I do not know who the author is and they do not know who I am. ",
"In a close knit field it is not that hard to guess about either side.",
"I am never flexible with anonymity. You need to be able to honestly review people but s... | [
"First of all, I applaud your commitment to transparency. I happen to think that peer review works better when reviews are signed, and even posted along with the article so that the whole process is open.",
"That said, you're still a grad student and may depend on some of these people for grants, jobs, or collabo... |
[
"If I dug into the Earth 2,000 miles, (roughly 1/4 the diameter), and stood in that space, would I experience only 75% of 1G?"
] | [
false
] | If gravity is based on mass then all the mass above my head wouldn't be pulling me to the earths core so I would experience less G's. This is supposing that the tunnel I dug is straight down and there's no mass above me. Contrastly, would I experience even less than 75% of 1G if I was transported to a bubble 1/4 under ... | [
"There is a small caveat to add here in that this calculation assumes a uniform density for the Earth which is not strictly true."
] | [
"Okay, first, there's a misconception in your question that I need to clear up: Even if you dig a tunnel straight down, the ground above you is still pulling up. You've removed the matter directly above you, but the matter all around the hole is still pulling up on you. In fact, in the grand scheme of things the ti... | [
"As others have pointed out, this assumes uniform density, which is very far from true for Earth.",
"In actual fact, because the core is very much denser than the mantle which is itself denser than the crust, gravity actually gets stronger as you get closer to the core, and only starts decreasing as you start pen... |
[
"If the universe is an hypertorus, is it possible that we receive the light from a star twice ?"
] | [
false
] | I recently read an article in a French science magazine stating that the universe might be an hypertorus (Euclidian, finite and borderless). They represented it using a cube in which when you exit through one side you actually come back in from the opposite one. I made a drawing to make my question clearer : The first ... | [
"Yep, if the universe is like that, then extremely distant things could be visible mulitple times. ",
"Researchers have looked for evidence for evidence of that",
" in the cosmic microwave background and haven't found any, which can be used to constrain the size of the potential torus that the universe might be... | [
"Woaw, great article, thanks for sharing ! This is fascinating but also pretty hard to wrap my head around."
] | [
"I think its worth pointing out that telescopes likely aren't powerful enough at the moment.",
"Let's assume its true. The cube with re-spawn on the other side (basically star fox multiplayer).",
"The first time the light from a star reaches you, it will have traveled simply the distance between you and the st... |
[
"Why do some animals get spotted fur as a result of domestication?"
] | [
false
] | Some animals that have a uniform coloured coat in the wild get a a spotted coat after X numer of generations under domestication. For example Cows and foxes. The frysian breed of cows here in the netherlands come from a uniformely clack/brown coloured bovine. The Russian domesticated foxes are a prime example. They sta... | [
"The prevailing thought is that this is due to ",
"gene linkage",
" between a major gene that influences aggression and at least one gene that influences color pattern. Gene linkage occurs when genes are very close to each other on a chromosome so the alleles for linked genes tend to be inherited together (so i... | [
"So if the alleles for coloration and aggression are either closely linked or dependent on some third gene, then would you expect solid colored house cats to be more aggressive than spotted or tortoise-shell colored house cats?"
] | [
"Citing \"an unnamed French Army Surgeon\" as an authority hardly research. Rushton and Bogaert were using flawed methodology to promote racism. Period. ",
"here - ",
"read some of this",
"it gives some more information on why their studies were popular (racism) and why they were unpopular (racism, bad data,... |
[
"How did the photographers of the first nuclear test ever know what filter and film exposure combination to use to get a clear image of it?"
] | [
false
] | I'm thinking specifically of of the Trinity test, though I know there is a whole series. If it was the first test ever, how did they know in advance how to photograph it without over or under exposing the film? | [
"There was a large team of people working on photography of the Trinity test, and they had dozens of cameras recording the explosion simultaneously. These were set to different settings, filters, speeds, distances from the blast, and so on. So they purposely spread out their range quite a bit. They even had a few t... | [
"Pseudoscience, denial, conspiracies...whatever you wish to call it, it is not welcome here."
] | [
"Pseudoscience, denial, conspiracies...whatever you wish to call it, it is not welcome here."
] |
[
"Measuring ecosystems: populations, biodiversity, biomass."
] | [
false
] | When I took zoology 101 in college we did a field study where we counted the number of species in a single square meter. What exactly do you call that type of measurement? More broadly. If you were to take a full inventory of biodiversity in a region, is there a standard set of measurements to take? For example. I know... | [
"Thanks...I'll be looking"
] | [
"There's something called Mark-Recapture where you tag a certain number of animals in a given region (let's say moose in a square kilometer), release them, come back later, and count the number of moose in the same area. Based on the fraction of tagged moose that you count, you can calculate how many moose are in t... | [
"Cool thanks for that... I was wondering how you handle the mobility of animals in such a study...or migrations too.. This should lead into some of that language I hope..."
] |
[
"If most people are vaccinated, what is wrong with people being non-vaccinated? Will the disease not stay isolated to those who are not?"
] | [
false
] | Just to be clear- IN NO WAY AM I AN ANTI-VAXXER, I AM UP-TO-DATE ON MY SHOTS, AND I FULLY SUPPORT VACCINATION AND MODERN SCIENCE. | [
"I'll add that the things we vaccinate against are subject to evolution, they can mutate in ways that would make the current vaccine ineffective. If enough people are vaccinated, the disease can be eradicated entirely, making future vaccinations unnessesary, however as long as there is some population where the di... | [
"I'll add that the things we vaccinate against are subject to evolution, they can mutate in ways that would make the current vaccine ineffective. If enough people are vaccinated, the disease can be eradicated entirely, making future vaccinations unnessesary, however as long as there is some population where the di... | [
"I think the issue, or part of it at least, is that some vaccines require that the child be a certain age in order for the vaccine to be administered. If a child who has not been vaccinated gets a disease, the other kids who have been vaccinated should be okay, but a smaller child who is not old enough to get the v... |
[
"Explaining human evolution to a six-year old?"
] | [
false
] | My six-year old asked tonight: after the dinosaurs died, how did humans become alive? I said that after the dinosaurs died, there was a lot more food for the little mammals that were around at the time and were more like mice and rabbits, and these mammals were then able to have lots of babies. Some of those babies wer... | [
"Hell we can't seem to be able to explain it to adults."
] | [
"Here is my try, you will have to change the language to suit the child, but hopefully the gist behind it will be helpful. It is written from your perspective, talking to the child.",
"Have you ever noticed how my father doesn't look exactly the same as me? Well, you will grow up to look different from me as well... | [
"Simple. Poignant. Refreshing. Well done. "
] |
[
"Will drinking beer or alcohol with a potentially tainted food kill the bacteria?"
] | [
false
] | I know that germs and bacteria cannot survive in an alcoholic environment, but could the alcohol from beer or mixed drink ingested at the same time kill it? | [
"The percent of alcohol in most beers (4-5%) is not enough to kill most bacteria."
] | [
"It might. Cooking the food can kill bacteria too. But that's not going to stop food poisoning, that's often caused by the toxins the bacteria produce, rather than the bacteria themselves. (For instance Staphylococcus aureus - staph food poisoning, Clostridium botulinum - botulism)"
] | [
"how much alcohol would it take?"
] |
[
"If you put enough of any kind of matter with hydrogen, like human beings, in a close enough space, would a star form?"
] | [
false
] | Or, could you render living material down to its component atoms and use only those materials to form a star? | [
"TLDR: Yes. If we define a \"star\" as a collection of material with sufficient mass to spontaneously ignite an exothermic fusion reaction, then it's true that bringing together a sufficient amount of material lighter than iron will form a star.",
"The Details: Stars form when clouds of dust and gas in space coll... | [
"Might be worth noting it isn't until 13 M_J that you get deuterium burning, and about 85 M_J until hydrogen. Heavier elements will be require even more. So, way more humans."
] | [
"Humans ",
"are mostly oxygen",
" (by mass, not count), and ",
"oxygen burning stars exist",
", so why not?"
] |
[
"Do cars accelerate better from a burnout or with traction control?"
] | [
false
] | Say, a tesla roadster is trying the 1/4 mile. Could it accelerate faster with traction control on or off? Also, how does this apply to gas powered cars? Is it better to apply the maximum ammount of torque before the tires start slipping or the maximum regardless? | [
"You want to apply the maximum, non-slipping torque. The reason being that the way you accelerate is by producing friction between the tire and the road. The greater that friction force, the faster you go.",
"It turns out for materials there are two \"types\" of friction, sliding friction or static friction. Slid... | [
"the best acceleration is achieved with about 5% wheel slippage, on typical DOT-approved, street-compound tires.",
"The key is at what rate of slippage is the coefficient of friction highest? At what rate is the most energy transferred through the contact patch to the ground? ",
"It's going to be highly depen... | [
"I would like to add to this that tire compounds on normal cars...are not meant to be warmed up to achieve maximum traction...so don't go doing burn outs in your mothers minivan."
] |
[
"Is \"sleep\" a particular defining characteristic for 'Animalia'? Are there animals that don't sleep?"
] | [
false
] | I'll add in any clarifications here, if needed. | [
"The kingdom ",
" includes animals without a developed central nervous system. \"Sleep\" is a function of the central nervous system (other than this fact I choose to not go into definitions of sleep at this moment.) ",
"From these two simple fact we can conclude there are indeed animals that don't sleep. Examp... | [
"Hmm, I meant is it a defining characteristic so that, for example, there's a large chunk of the evolutionary ancestral tree that \"sleeps\" and another chunk that does not?"
] | [
"This has been asked before (try a search on the sidebar). There are some exceptions, but almost all animals that have been studied in-depth show sleep or sleep-like states, including worms and insects."
] |
[
"What is a neurotransmitter \"turnover rate\", with reference to acetylcholine? What does it mean if the turnover rate is increased or decreased?"
] | [
false
] | I'm learning about various neurotransmitters (especially acetylcholine) and I keep seeing "turnover" or "turnover rate" in academic papers. Any help would be much appreciated! | [
"Turnover rate is relevant for neurotransmitters which are degraded within the synapse. Some NTs are not (see serotonin- not degraded within the synapse to a significant degree, mostly reuptaken by the presynaptic side). Acetylcholine on the other hand is degraded by acetylcholinesterase within the synapse, and its... | [
"Something about this response just feels like it's from ChatGPT... am I right, or just paranoid?"
] | [
"Something about this response just feels like it's from ChatGPT... am I right, or just paranoid?"
] |
[
"How do medications cause weight gain?"
] | [
false
] | Does it throw off hormones and make you eat more? Does it reduces your metabolism so it allows more of the calories you eat to be stored instead of used? | [
"It depends on the type of medication. Some cause you to eat more because they stimulate appetite. Some do lower metabolism rate. Some cause you to retain water, which obviously doesn’t cause fat accumulation but it does affect how much you weigh. Others can even affect how your body stores and processes sugar. "
] | [
"https://www.urmc.rochester.edu/encyclopedia/content.aspx?contenttypeid=56&contentid=DM300",
"That’s a link with some of the more common types that do. And with some specific names. For your viewing pleasure. "
] | [
"I wish they would say exactly which one they did. Its become a pathetic excuse for people that just overeat."
] |
[
"Is there actually any evidence to suggest \"screens\" are bad for children?"
] | [
false
] | null | [
"A couple years ago I finished my degree in Human Development. There are quite a few studies on how TV effects kids behavior and learning. They basically go in the way you'd expect. If the kid watches violent shows, in the short term they are more violent. Similarly, if they watch educational shows, they have a sho... | [
"Agreed. There are a lot of studies on this. It is not the screen itself but the effects of having tv or other programming on that disrupts language development and parent child interaction. Even Sesame Street! See citations in this AAP publication ",
"http://m.pediatrics.aappublications.org/content/128/5/1040.fu... | [
"What do you mean by harmful? Physical, psychological, cognitive? Do you mean the screens as a device or the content played on those screens? \nSome perspective with all the supposed sensationalist research is that despite this ephemeral idea of \"children\", they are still just people and people are all different.... |
[
"Are the two electrons in the Helium atom in the same energy state?"
] | [
false
] | Are the two electrons in the same energy like two non-interacting electrons in a hydrogen atom (hypothetical) where the groundstate is degenerate due to spin? Or are the two electrons in different energy levels due to Coulomb repulsion? | [
"The single-particle orbitals that come from solving the TISE for non-interacting electrons in the nuclear mean-field potential do not accurately describe the ground state of the helium atom. The actual many-body state of the atom can be written as a linear combination of single-particle configurations. Since the a... | [
"The single-particle orbitals neglect ee-interactions, but you are attempting to account for them by allowing the ground state to be an admixture of single-particle orbitals."
] | [
"So, If you are asking if the electron in a helium ion has more or less energy than one of the electrons in neutral helium, the answer is less. One way to think about this is that in the helium atom, both of the electrons are are pulled toward the two protons in the nueclus, but because the electron wave function e... |
[
"Why do flies swarm at the top corners of my office building?"
] | [
false
] | null | [
"there may be stagnant water in the gutters. these insects look like mosquitoes so i am going to amuse they are and mosquitoes love stagnant water."
] | [
"Are you sure they are flies? ",
"Bees swarm",
" like this; it is part of their re-productive cycle. They outgrow their current nest so a portion of that breaks off with a new queen and looks for a new nest; this is typically the swarm phase.",
"During the swarm most of the bees are huddled near/around the ... | [
"They're definitely not bees - they're small, so it's difficult to get a good photo, but I lucked out and found a spiderweb on the outside of a window near the corner, so ",
"here's a lot of dead ones on the web",
".",
"I've only noticed them this year, but my coworkers assure me they show up every year, and ... |
[
"Can corroded galvanized iron be visually distinguished from non-galvanized iron?"
] | [
false
] | I am currently working on a project without a conservator/chemist handy and need to answer the following question. Can galvanized iron fasteners be visually distinguished from regular, un-galvanized iron fasteners after 80+ years of corrosion. Most of the corrosion would be a result of exposure to sea water and coastal... | [
"Corroded galvanized steel usually looks like white flakes/crystals over rusted steel. If you are unable to find any visible indication of either silver-colored zinc or white flakes, especially in the hidden areas of the bolt, it was likely never galvanized.",
"If you can remove a bolt, probably by cutting at thi... | [
"Thanks. The fasteners are actually part of a shipwreck I am studying. ",
"The wreck is from the late 19th century and would probably have used plain iron. Do you know if the zinc would still have corroded white if applied to iron instead of steel? My knowledge of chemistry is pretty basic but I imagine it would ... | [
"Yes, it would look similar. It's the iron in steel that creates the iron oxide (Fe",
" O",
" If I remember correctly and the formatting works) known as rust.",
"The late 19th century was when steel started replacing wrought iron in most uses, so you might actually be looking at steel."
] |
[
"What would happen if a positron encountered a negative muon?"
] | [
false
] | As is common knowledge among the physics community when positrons encounter electrons they mutually annihilate each other into two high-energy gamma rays. Though what would happen if a positron encountered a negatively charged muon? Seeing as though they have opposite charges you would expect the same result. However, ... | [
"Having opposite charges is not enough for two particles to annihilate, they have to be ",
" antiparticle. You can’t have annihilations between positrons and muons.",
"So what happens when they interact? There’s lots of possibilities, depending on the available energy. They could just scatter elastically, or at... | [
"Annihilation only occurs when a particle encounters its antiparticle, therefore a muon will only annihilate when encountering an antimuon. Most likely occurrences (depending on the system energy) are scattering, electromagnetic interaction (exchanging a photon) or weak interaction (exchanging a W/Z boson).",
"In... | [
"It decays with a half-life very close to the half-life of a free muon."
] |
[
"Could we test whether someone has been exposed to lead poisoning as a child, even if they are now an adult?"
] | [
false
] | If you were exposed to lead poisoning let's say, as a 5-year old, would it then be possible to do some kind of nerve biopsy, etc... to determine the of your nerves; in order to confirm or deny if lead exposure occurred? I don't know how difficult that would be, but theoretically, shouldn't it be possible to assess whet... | [
"If they experienced lead poisoning as a child, it would probably be less invasive and ",
".",
"Before the epiphyseal plates fuse in adulthood (~20 years old), the long bones (i.e. proximal femur, right below the hip) growth very fast and are constantly depositing minerals inside the bone. In addition to the ca... | [
"Wow thank you for such an in depth response. ",
"Why does lead leave a dark bluish line between teeth and the gum line?",
"And oddly, what is the significance of child abuse? Meaning intentional poisoning?",
"And lastly is it really that fatalistic? Should there have been damage, there is no opportunity, eve... | [
"I'm not sure about the Burton line, but it is probably attributed to a combination of bleeding, relatively inaccessible area (hence need good brushing), and external incorporation into the teeth (like coffee stains).",
"More relevant would be child neglect, but this would be brought up really only if there are o... |
[
"How is there angular momentum in an electron when the Bohr orbital-movement model has been disproven and the static electron energy cloud is accepted?"
] | [
false
] | it makes sense to talk about angular momentum when there is a satellite circulating around a core but when you just have a negatively charged static/unmoving energy field emanating around a core, how do you interpret this? I've seen pictures in high school chemistry that show beautiful patterns in the probability densi... | [
"In this case, momentum is a bit of a bad name. For an electron, there is always an angular momentum. Always. You cannot stop it. ",
"It sucks to accept, but it works to describe interactions and when you get into symmetry arguments in subparticle physics, the need for an intrinsic momentum for electrons is prett... | [
"Very interesting that you mention this as I have just asked this question :D",
"http://www.reddit.com/r/askscience/comments/t0fj9/does_an_electron_cloud_vibrate_like_a_standing/",
"thanks for all the answers. I will write more questions as I try to understand the responses."
] | [
"It isn't static in the sense that it has no motion, but that it stays in the same shape. It's a standing wave that oscillates, and it does have net motion around the center, in a sense.",
"Those probability clouds you saw were visual representations of the position wavefunction, which has complex values at every... |
[
"How did the Gamma function arise?"
] | [
false
] | Taking the definition from : the factorial of a non-negative integer n, denoted by n!, is the product of all positive integers less than or equal to n. So how and why are we able to extend this definition into non-integer values or even complex numbers? Specifcally, how did we find the definition of the ? | [
"Integration by parts of the Euler integral of the second kind shows that:",
"Γ(t) = integral from 0 to infinity x^(t-1) e^-x dx = \n - lim x->infinity x^(t-1)e^-x\n + 0^(t-1)*e^-0\n + integral from 0 to infinity x^t/t * e^-x dx\n",
"The limit is 0, the expression on the third line is 0, and the expres... | [
"So i guess that the wolfram alpha link also meets the f(1) = 1 requirement and the f(t+1) = t f(t) but not the log(f(t)) convex. ",
"It also satisfies the convexity of log(f(t)). It is just another integral (this time a definite one) whose solution is the Gamma function. Both integrals define the same function, ... | [
"Which i interpretate as that the Bohr-Mollerup theorem proves that no \"good\" interpolant for negative factorials can be found. Could you elaborate on the meaning of \"good\" here and why this is affected by the Bohr-Mollerup theorem?",
"If Γ(n) is meant to be an extension of the factorial function (n-1)!, then... |
[
"If there was a huge solar flare that hit the earth would everybody (or anybody) die or just the people on the daylight side?"
] | [
false
] | null | [
"The primary danger from solar flares isn't to us humans, but rather our infrastructure. A powerful enough solar flare can essentially destroy our electrical grid as well as knock out any satellites in the way. This could result in a loss of life due to a lack of power over an extended period of time.",
"Unless o... | [
"can essentially destroy our electrical grid as well as knock out any satellites",
"I would like to see sources about that. It could certainly, if powerful enough, have some effects on the power grid, but destroy it ?"
] | [
"According to Dr. Phil Plait in his book ",
"Death From the Skies",
", a powerful enough solar flare has the capability to overload power lines and transformers, which is why I said ",
". Because obviously if every power line and transformer is blown out or snapped it's not going to be a simple repair."
] |
[
"Why do some viruses, such as influenza, quickly mutate (thus require different vaccinations annually), but other viruses, such as smallpox seem to barely mutate at all (or at least much more slowly)?"
] | [
false
] | null | [
"One reason why is that viruses like corona and influenza are single stranded RNA viruses and small pox is a double stranded DNA virus. ",
"If you have a single stranded genome, there is no repair mechanism and mutations occur much more frequently."
] | [
"Another reason for some viruses such as influenza is that their genome is actually segmented! If a host has more than one strain of influenza, the segments can be mixed up and you have a rapid sudden form of mutation called antigenic shift. The other commonly known form of mutation that occurs over time due to rep... | [
"You say “viruses like influenza”, but in fact it’s not viruses ",
" influenza, it’s ",
" influenza that does this. Influenza is unique in the virus world in its ability to evolve to avoid population immunity. Technically, influenza doesn’t mutate fast than other RNA viruses, but its surface proteins are more t... |
[
"What connection is there between the esophageal sphincter and your ears?"
] | [
false
] | Is there any nervous system or other connection between the esophageal sphincter and the area on both sides of your neck that run up it and behind your ears and into them? What would the reason or mechanism of why a person would experience pain in that region when getting an esophageal spasm? Is this "referred" pain fr... | [
"Are you referring to the upper esophageal sphincter or the lower?"
] | [
"It's just that there are two of them, so it really depends which one. I'll try to get to this later today."
] | [
"Alright here we go.",
"The esophageal sphincter is innervated by the ",
"vagus nerve.",
"This nerve does also have a branch called ",
"Alderman's nerve",
" which goes to the exact region of the ear you're referring to.",
"The vagus nerve is well known when speaking of referred pain, and would be the li... |
[
"There are many helpful bacteria inside the human body. Do we have any such viruses?"
] | [
false
] | [deleted] | [
"Maybe. ",
"Hepatitis G",
" might play a role in suppressing HIV. But generally speaking we don't have the same relationship with viruses as we do with bacteria. Bacteria we actually really need to survive."
] | [
"Not on purpose. Viruses are bags of RNA or DNA. They float around with the sole purpose of reproducing. The viruses reproducing often hurts us. It takes over our cells machinery, eventually killing the cell. I don't think any virus could be beneficial or evolve to be beneficial on purpose.",
"Bacteria are differ... | [
"Yes, countless billions, although probably not the ones you might have heard of. Every surface of your body, inside and out (skin, mouth, gut, genitals etc) is covered in microorganisms: mostly bacteria, but also fungi and viruses that infect bacteria, called phages. ",
"These microorganisms form complex ecosyst... |
[
"How to measure decibels in a MRI machine"
] | [
false
] | This is somewhere between DIY and AskScience. I have an (unpaid) internship and the doctor I'm working for is interested in measuring the decibels experienced by someone undergoing an MRI. I know that this has been measured to some degree already, but she wants a way of directly measuring in an active MRI. My plan was ... | [
"I used to work in a lab where they made devices for delivering ultrasound inside an MRI. I can probably hook you up with some experts if it comes to that."
] | [
"Do you need to make good measurements on the MRI while you're measuring the sound levels? If not then you don't have to worry about a recorder's electronics screwing with the signal."
] | [
"Well, I think the concern is for the electronics of the recording device (and/or its attraction to the magnet)."
] |
[
"Does quantum mechanics prevent one from (hypothetically) measuring the gravitational field of a particle to determine its position and velocity?"
] | [
false
] | This is just a thought experiment. Could the path of a particle through a two-slit apparatus be determined using a device that could measure the gravitational field of a particle with unlimited sensitivity? Would there still be an interference pattern? | [
"There is no reason to suppose that gravity doesn't follow the rules of quantum mechanics to this basic order. So no, you cannot use gravitational effects to bypass the uncertainty principle. In fact, the uncertainty principle is probably the most certain part of quantum mechanics. It is incredibly unlikely that an... | [
"Correct me if I'm wrong, I've never worked in a laboratory with small scale gravitational effects, but the largest problem with your idea is what you mean when you refer to \"measuring the gravitational field\" of a particle. ",
"The way we measure gravitational fields is by observing their effects on other obje... | [
"The influence of gravity can be detected in quantum mechanical systems. In fact, it can induce quantum interference. See ",
"Phys. Rev. Lett. 34, 1472–1474 (1975)",
"."
] |
[
"What would happen if you left a steak on the Moon?"
] | [
false
] | It doesn't have to be a steak - any cut of meat would work. Assume that it's not in a bag or any protective housing. How long would it last, and are there any circumstances where someone would be able to eat it afterwards? What would happen to them? | [
"It will freeze-dry at night and boil in vacuum during the day. ",
"With a bit of practice, salt and spices you could probably do a decent beef jerky. Be warned that the surface of the moon is rich in calcium oxide and other basic compounds, which are bad for you and will make the steak taste bitter. Use only cle... | [
"Steak in interstellar space is actually an interesting problem.",
"Going off Wolfram Alpha's phase diagrams, water is a solid even in vacuum if the temperature is low enough. Get a couple of AU away from the sun and even an impure \"comet\" like your steak should be very stable.",
"I can't guarantee total edib... | [
"I wanna go a bit furhter...if you just tossed a cut of meat into space, or anything biodegradable, away from the heat of any star, would it freeze dry and be good, theoretically, forever, since it is locked in a no oxygen vacuum of frozen space? Or, since there is water liquid in some materials to begin with from ... |
[
"Could noise cancelling devices be built into machinery thus reducing damage to operators and noise pollution.?"
] | [
false
] | I was reading of the ways noise pollution is affecting marine mammals and birds in urban areas and kind of had this brain wave; would it be possible? | [
"The problem with noise cancelling is that it's immensely location specific. You have some environmental source of sound waves, and then you have a source of sound waves to destructively interfere. But if you look at a drawing of ",
"interference patterns",
", you'll note that there are points where they destru... | [
"It depends on where the noise is coming from. You can put a muffler on a car engine but you can't exactly mask a concord's sonic boom. Any specific machine you had in mind? In general, making something quieter will usually be more expensive and less effective."
] | [
"I think OP means noise canceling as in what is used in head phones and mobile phones..\nIt's interesting, \nI've wondered if we would ever see noise canceling devices for people who live close to railway lines and busy roads..\nIt could be done but I don't think it blocks the actual sounds from damaging our ears ,... |
[
"If motion is relative, why is it (theoretically) possible for one massive object to move in 0.5c in one direction and for another to move at the same speed in the opposite direction?"
] | [
false
] | [deleted] | [
"It's perfectly possible for the relative velocity of two objects, as perceived by an external observer, to be greater than the speed of light. This is not a contradiction of the fact that nothing can travel faster than the speed of light because relative velocities are not the same in different reference frames in... | [
"Length contraction/ time dilation (The reason I can answer with both is they're two sides of the same coin).",
"Person A will see the distance travelled by person B to be smaller in one second making B's speed slower, or equivalently they'll cover the same distance, but it will take a bit longer than a second."
... | [
"There is a difference between ",
" velocity of a ",
" object and ",
" velocity as seen from some inertial frame. The maximum ",
" speed is c and the maximum ",
" speed between to objects is in the case of to massless particles moving in opposite direction and is in this case 2c.",
"Now let's consider y... |
[
"Vaginas contain lactobacillus, which are needed for healthy digestion. Do we know if performing oral sex in one can have health beneficts?"
] | [
false
] | Sorry for the stupid question, but I couldn't get this out of my head. Also, sorry for the maybe weird phrasing of the question, English isn't my first language | [
"Shirt answer: no.",
"See my other reply for details.",
"Tl;dr: lactobacillus in vagina and gut are different at species and strain level (in healthy women).",
"Cunnilingus is no free probiotics treatment.",
"Also, don’t try to make “vagina yoghurt”. (Please...).",
"Source: I am an academic researcher on ... | [
"Follow up question - is the bacteria in a birth canal related to gut bacteria in a healthy person?",
"How much of a person's gut bacteria depends on vaginal birth and passing through their mother's bacterial cultures?"
] | [
"Apparently oral sex can have health impacts, but not positive ones. There has been ",
"some studies",
" that show that men who have had more oral sex partners are at an increased risk of throat cancer."
] |
[
"When a truck drives behind another truck to reduce drag, does it slow down the truck in front?"
] | [
false
] | I was just thinking about this on the highway yesterday and realized I have no idea how drag and slipstreams work. Does the truck in front create some sort of low-pressure zone that "pulls" the back truck along? Does that somehow require more energy from the front truck? | [
"The turbulence behind the un-aerodynamic rear of a truck adds to the drag on the vehicle. If another truck is close behind that turbulence is reduced, has less volume in which to operate. Therefore the presence of the second truck should actually ",
" the first truck. The second truck takes up the burden of rear... | [
"Okay my brain just exploded.",
"Does this imply that, if/when inter-car communication matures, and vehicles are able to convoy on highways in very close proximity, ",
" fuel usage should decrease significantly, including that of the guy in front?"
] | [
"Yes."
] |
[
"My wife is convinced that the full-body scanners that are now being used in some airports cause cancer, and thus refuses to use them. What is the evidence for or against this?"
] | [
false
] | null | [
"If the top scientists in the area are constantly arguing over it, I doubt we'll be able to reach any absolute conclusion here at askscience.",
"Personally, I always try to minimise my exposure to ionising radiation. I would not be keen to go through one of those backscatter scanners, however it is clear that if ... | [
"I would start reading ",
"here",
". Looks controversial."
] | [
"How these devices were approved seemingly without empirical studies on whether they cause DNA damage is beyond me.",
"It's troubling but not unexpected.",
"I remember reading about these X-ray machines that were once used to fit people's shoes decades ago. Eventually it was revealed they cause cancer and now ... |
[
"Dear r/askscience panelists, what is a question you would love to be asked, and what is the answer?"
] | [
false
] | About your field of research, of course. I figure some of you must be dying for the right question to be asked here. Also, there are a lot of fields I didn't even know existed (historic cooking, anyone?) and would love to know more about them but I just wouldn't know what's a good question to ask. | [
"This reminds me of a story I heard. On a physics exam, a professor put \"Write a question appropriate for this class, and answer it.\" The student put down. \"Write a question appropriate for this class, and answer it. Write a question appropriate for this class, and answer it.\" Technically, he was correct."
] | [
"Any question beginning with the phrase \"I think I've disproved\" and then something like relativity, quantum mechanics, the ideal gas law or the second law of thermodynamics. Cause I just can't get enough of those."
] | [
"Seeing as the professor put the question on the exam, it must have been an appropriate question for the class, and so, the student answered with the same question to which the answer, of course, was the same question yet again."
] |
[
"What % of my weight am I actually lifting when doing a push-up?"
] | [
false
] | null | [
"Your question made me curious and a quick search yielded the study linked below, which looked at exactly this question.",
" The researchers found that the answer depends both on the variant of the exercise as well as the stage of the exercise. For example, in a traditional push-up the number is about 69% in the ... | [
"You can also modify pushups in the other direction, making them significantly harder (mostly through increased leverage): ",
"Note: at no point do you lift 100% of your own body mass, since your hands and forearms are always at rest and all of the motion is above the elbow. ",
"Edit: body segment weight data ... | [
"To measure yourself: Put a bathroom scale under one of your hands while doing a push up. Double the maximum value the scale lists and divide that by your total weight (and multiple by 100) to calculate the percentage."
] |
[
"Is there an enzyme that could break down steel? Could you apply a certain growth medium to a steel girder and grow a bacterium capable of breaking it down?"
] | [
false
] | null | [
"Howdy! I've removed your post for its open-ended and speculative nature. I can redirect you towards ",
"/r/AskScienceDiscussion",
" which better suits such posts."
] | [
"Oh man! I really wanted an answer. Could I resubmit it in a more concise manner?",
"\"Is there a biological way to break down steel?\""
] | [
"I think that's a great rephrasing. Go for it, but message back so I can release it promptly. I'm curious to the answer as well.",
"To be clear, it was the second half of your post that got it removed."
] |
[
"I'm in a bad mood. Physiologically speaking, what's going on? Are there well-understood neuro-biological factors keeping me from enjoying my work? Is there a theory about the evolutionary benefits of being surly?"
] | [
false
] | [deleted] | [
"Usual disclaimer: I am not working in the field, but being grumpy in the short term is consistent with the game theory strategy called \"tit for two tats\". ",
"http://en.wikipedia.org/wiki/Tit_for_tat#Tit_for_two_tats",
"Basically, you try and take advantage of me once, and I let it go, because sometimes shit... | [
"First: your question and subquestions are all buzzwords and things that don't belong. Evolutionarily whatever is not required. Physiologically is pretty hard to answer (individual differences). Neuro-biological blah blahs. ",
"You're in a bad mood: that's emotion. There is a wealth of knowledge on emotion from p... | [
"Sure, let's clear away the confusion. Remember, I use \"all buzzwords\" because I don't know jargon.",
"RE: mood.\nI started here:\n",
"http://science-education.nih.gov/supplements/nih2/addiction/activities/lesson1_brainparts.htm",
"Where I acquire my first \"blah-blah\": neurobiology. Which says the frontal... |
[
"Could humans survive in temperatures above 120°F?"
] | [
false
] | Considering that we can be comfortable in a hot bath around that temperature, I was wondering if that were applied to the air temperature, could we go on as normal (besides being pretty damn uncomfortable)? | [
"Humans have survived---amazingly---temperature of >250°F for tens of minutes, in temperature homeostasis experiments initiated by Sir Charles Blagden in the 18th century. The key was that it was a dry heat. The resulting sweating was abundant, but there were no permanent health problems. (A steak brought into the ... | [
"It depends on what you mean by \"survive\". You can be exposed to elevated temperatures like that for a while, but, eventually you will develop heat stress. How long it takes you to develop that heat stress depends on a number of factors, like how active you are, hydration, clothing, etc.",
"There are PHEL cur... | [
"I am going to assume that you are talking about sitting as you would in a bath, in the shade with an air temp of 120F. ",
"Yes. Provided that you are in a dry area and that you get a lot of water. Temperatures near this are common in Las Vegas, Phoenix, and Death Valley. People still work outdoors in it. Constru... |
[
"How did the cowboys keep air conditions on their buildings for their saloons in when they use those butterfly doors?"
] | [
false
] | null | [
"Air conditioning didn't start being common until the 50's, half a century after when typical movie style saloons were common."
] | [
"I know for sure place like movie theatres had them too. I assumed the regularplaces like restaurants and stuff had them aswell"
] | [
"Depends on which era you are talking about. Classic \"far west\" cowboy saloons from the movies are usually depicting places from before 1910 with the peak of the Old West outlaw kind of period in the 1870's and 80's. The first air conditioning installations did not begin before 1906."
] |
[
"How does sodium nitrite sharpen a heated tungsten rod?"
] | [
false
] | null | [
"That was the flair bot bothering me for the chemistry label, if anyone is wondering."
] | [
"That was the flair bot bothering me for the chemistry label, if anyone is wondering."
] | [
"That was the flair bot bothering me for the chemistry label, if anyone is wondering."
] |
[
"What happens after a black hole is formed? Does it just grow and never go away? What will it be in the long run?"
] | [
false
] | null | [
"Currently black holes that form only grow. They emit Hawking radiation, however - very weak but still present. In the very distant future, when there is not much left that can fall in, Hawking radiation will win and the black holes slowly lose their energy (and therefore their mass) until they evaporate. It is unc... | [
"To elaborate, right now a black hole doesn't even have to be 'fed' with infalling stars, planets, dust and whatnot: what looks like empty space to us is energetic enough for that. That is, the black hole receives more energy from the cosmic microwave background than it emits due to Hawking Radiation. Over immeasur... | [
"Technically they are growing because they absorb photons that hit them and radiate very little energy but I wouldn't picture normal stellar mass block holes as some giant thing that just sucks up everything in it's surrounding and constantly grows ever larger. Mostly they just sit there and hangs out like most oth... |
[
"Can 241Am spontaneously generate 243Bk?"
] | [
false
] | As most of you may know, Berkelium was discovered after a surface of Americium-241 was bombarded with high energy alpha particles. This had got me wondering; as 241Am decays, it can occasionally produce a high energy alpha particle. If said alpha particle hits the nuclei of a nearby 241Am nucleus, wouldn’t that generat... | [
"Am primarily emits two alpha particles whose kinetic energies are around 5 MeV. The Coulomb barrier for ",
"He + ",
"Am is almost 30 MeV. So the probability of any given alpha particle actually undergoing a reaction with a ",
"Am nucleus is going to be very small."
] | [
"If you start with a 100% pure sample? Probably zero.",
"Americium-241 + alpha = Berkelium-245 as an alpha particle has 2 protons and a total of 4 nucleons. Only alpha and beta will never get you to berkelium-243. And of course the probability of this reaction is tiny.",
"Americium-241 has a very small chance o... | [
"So theoretically speaking, in say a 1 gram sample of Americium 241, how many atoms of Berkelium would be in there at any given time?"
] |
[
"What actually kills you when you are dehydrated?"
] | [
false
] | What goes on in your body that causes you to die from dehydration? | [
"The two most significant issues with severe dehydration are the loss of perfusion volume as well as the electrolyte abnormalities that develop. If someone is hypovolemic enough, they will not be able to maintain an adequate blood pressure to supply oxygen to their organs, which results in multi-organ failure (in ... | [
"If you don't drink enough water, your blood pressure can drop to dangerous levels. Because blood carries oxygen throughout your body, your organs, like your heart and brain, would start to fail due to the lack of oxygen. Additionally, lack of water would also cause the concentration of electrolytes, such as sodium... | [
"Can I have that in slightly more simplified English? No sarcasm, just a bit over my head."
] |
[
"Is it possible to have Auditory Hallucinations that are more positive than negative?"
] | [
false
] | this might be a dumb question, but has there been any recordings/ examples of people having auditory hallucinations, but they give that person a better outlook in life? all that i've seen are about people having horrible voices telling them to die or say how dumb they are.Thank you | [
"This is a bit anecdotal but there was an AMA on here a couple years back by a Schizophrenic who heard auditory hallucinations from 3-4 distinct voices, each with a different personality. One was very evil and demonic, one was a bit more childish and I think the other was friendly. If I recall correctly there wou... | [
"For a good read on the subject I highly recommend Musicophilia by Oliver Sacks. Or for the lazy he has a few YouTube videos where he summarizes parts of his book."
] | [
"Another example of auditory hallucinations that may be pleasant is musical hallucinations. Some people find them irritating or disruptive, but others may enjoy them.",
"Link that mentions pleasant musical hallucinations in passing: ",
"http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3105559/"
] |
[
"Why was the curiosity rover not landed at the poles where there is clear signs of ice water?"
] | [
false
] | Curiosity's main goal in to find out if Mars was ever hospitable to microbial life but is completely ignoring the opportunity to sample ice that may actually have microbial life. Why did they decided on Gale creator? | [
"That's a fair question with a few different answers. I am on the MSL science team and a major chunk of my PhD thesis was on Gale as a potential landing site, so I'll do my best to explain. If you want more detail, you can check the blog post I wrote when Gale was selected: ",
"http://blogs.agu.org/martianchronic... | [
"Why would you expect solid ice at less than -60 degrees to have microbial life? Any ice deposits at the poles are from precipitation (i.e., snow), whereas the equatorial target sites all have extensive evidence of ",
" water in the past. Gale crater was chosen for its diversity of aqueous minerals and its extens... | [
"Someone will be able to fill in the gaps and give you the fine details, but basically Curiosity, from what I understand, is going to be checking out what is going on with the seasonal methane production on Mars which doesn't seem to be coming from the poles. Scientist have deduced it is \"produced\" and not just t... |
[
"How far away can the Earth's night lights be seen from?"
] | [
false
] | I was looking at some videos of Earth from space at night (or since you're in space, I guess it's more about what side of the planet you're on rather than what time of day it is) and I wondered how far these lights can be seen from. Can you still see them when you're halfway to the moon? | [
"With the unaided eye? With a telescope?",
"With a shield to block the sunlight or without?"
] | [
"Can you answer each scenario?"
] | [
"I can't figure out how luminous the artificial lights of the earth are, so I can't get to a complete answer for you. I will provide the means to answer your question, with the hopes that someone can find this missing piece.",
"I'm going to start with the assumption that either the sun is totally eclipsed by the ... |
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