title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"How does drowning work?"
] | [
false
] | null | [
"I'm going to correct you here.",
"The urge to breath is based on our carbon dioxide levels not our oxygen levels. The urge to breat becomes great when we reach higher levels of carbon dioxide, while we still have sufficent oxygen to stay alive for a suprising ammount of time."
] | [
"When people drown, do they eventually reach a point when they take a breath under water or is that biologically impossible?",
"There are two types of drowning.",
"http://answers.webmd.com/answers/1177901/what-happens-during-drowning",
"a. suffocation where the person doesn't get appreciable water in lungs",
... | [
"Hmm yeah that's interesting. Thanks for answer! I didn't think about it that it could go both ways."
] |
[
"What is Deja vu and how can it be explained?"
] | [
false
] | null | [
"The best explanation i have heard is roughly; It is by coincidence or fault in brain chemistry, that a pattern of neural pathways in the brain are activated which have been activated before at some point. The brain then tells you it is the same experience as before but because you know it isnt, you enter a brief ... | [
"Hi, I'm following this vsauce guy on youtube. He expains a lot in a good way!",
"http://www.youtube.com/watch?v=CSf8i8bHIns"
] | [
"I'll check back later if your answer is the best because that's it what I was told also.",
"The brain has short-term memory and long-term memory and Deja Vu is really just a mix up between these two because it stored the \"new\" experience in the long-term memory and you are like: i've seen this before and are d... |
[
"How do we know the indeterminacy principle is not illusory?"
] | [
false
] | With sub atomic particles "appearing and disappearing" or "disappearing then appearing else where" or "existing then not existing". Is it possible they simply move so fast that it appears to us there was no time between the particle moving from point 'A' to 'B'? So when we say that sub atomic particles do not occupy a ... | [
"So at its heart, this is the same question (or philosophically very similar to it) that Einstein was asking in the ",
"EPR Paradox",
": is quantum uncertainty (or indeterminacy) ",
" or is it just an artifact of the measuring problem? That is, even accepting that the limits on our perception of the informati... | [
"Either you misunderstood my post, you misunderstand the Uncertainty Principle, or both.",
"The HUP is a fundamental and intrinsic fact of nature. It is independent of the mathematics we use to represent it.",
"I understand what you're trying to say. When we come up with a theory, we create a mathematical model... | [
"The HUP is a consequence of the mathematics of QM. The mathematics of QM have not failed us yet, so assuming that the HUP is true is a reasonable assumption. Physicists everywhere assume the HUP is true all the time, and every experiment I've ever heard of has agreed with it.",
"I don't know if we'll ever have d... |
[
"Why does the iron filings and bar magnets experiment result in the iron filings arranging themselves in neat lines when the magnetic field should be continuously distributed around the magnet?"
] | [
false
] | Like ? | [
"Because each tiny piece of iron becomes magnetized itself, and now you have a giant pile of tiny magnets that all attract and repel each other. The attraction and repulsion of the individual tiny magnets lead to spaced-out-lines pattern you see."
] | [
"By that, if you dropped/buried a bar magnet in a bucket of iron filings would if form layered shells with gaps between them?"
] | [
"If you did it in zero G, yes. On Earth, gravity will dominate over distances greater than a few mm/cm. ",
"This is basically the same thing as those ",
"desk toys",
" that have a jillion small metal bits and a strong magnet in the base. You can try building a tower out of the metal bits, but if you tower get... |
[
"Can animals (ones capable of domestication) tell if you are male or female? Do they treat you differently/ acknowledge you accordingly depending on your gender?"
] | [
false
] | How about implications of homosexuality or transgenders? Do gay male animals treat male humans differently from heterosexual animals? What if the male humans are homosexual and the animal is not? And what if both are? | [
"I'm no homerun hitter but I'll step up to bat: The answer appears to be yes, at least with dogs.",
"Link: ",
"http://www.anthrozoology.org/pdf/anthrozoology.pdf",
"relevant bit starts on p. 136",
"Human gender had\nan effect on both dog barking, and eye orientation. Dogs showed a stronger decrease in barki... | [
"How much of this could be due to how a male appears and projects himself onto others compared to females though? The sample size of 3 women and 3 men appears a bit small to totally account for this and could be a factor"
] | [
"Related question:",
"Do dogs recognize and react to human age?"
] |
[
"How can any CD or DVD be re-writable?"
] | [
false
] | [deleted] | [
"Actually, that's not how ",
" CDs are created. Pressed, or manufactured, CDs do have microscopic indents in them, but writable and rewritable CDs and DVDs actually use a photosensitive dye- in the case of rewritable discs, a dye that can be reset back to its initial reflectivity."
] | [
"It's actually based on the power level of the laser beam- it gets much more powerful to return the phase-change \"die\" to its original state. That's why rewritable discs have to be fully erased before being written to again- there's no guarantee that erasing one cell won't affect any others."
] | [
"I assume there are two different frequencies of laser light, one that sets it and one that resets it? If not, how is it done?"
] |
[
"How are we so sure that there are no \"paranormal\" exceptions to natural laws?"
] | [
false
] | null | [
"If science deals with what can be replicated and controlled, and \"paranormal\" phenomena cannot be separated from the \"noise\" of random variables in the universe, how can one claim that \"paranormal\" phenomena exist?",
"Another way of asking: \nIs your friend suggesting that is impossible to replicate experi... | [
"You can't prove something doesn't happen. What you can prove is that something happens, in a certain controlled situation. If someone claims to have some paranormal ability or tool to influence the world, it should be measurable. Science is forming an idea, describing an experiment to validate that idea, setting i... | [
"Definitely related. The null hypothesis is often \"the observations are due to random chance\", and sufficient evidence can disprove this. If the evidence gathered does not disprove the null hypothesis to a sufficient confidence, that does not prove that the process happened by chance."
] |
[
"Is the earth still cooling from its formation? If so, does that mean eventually all tectonic activity will cease and our liquid mantle will solidify?"
] | [
false
] | null | [
"Yes, the earth is still cooling from formation, specifically heat generated by accretion and differentiation. A lot of the heat is actually due to radioactive decay of things like thorium-232, uranium-238, and potassium-40. A good discussion of the topic can be read over at ",
"Wikipedia",
". ",
"One thing t... | [
"The Earth is cooling at a rate of ~100C/billion years. So the sun is going to die and engulf the planet before we completely cool down (in around 5 billion years). ",
"Here's a press release from a Science article",
" that came out a few years ago that discusses how much heat the Earth still has."
] | [
"That is mind blowing that the Sun will die before the Earth completely cools."
] |
[
"Why are dendrites 2-dimensional, rather than 3-dimensional?"
] | [
false
] | I'm studying dendrites formed by electrodeposition of zinc in an alkaline solution, but this could probably apply to dendrites formed in a binary alloy solidification process just as easily. Why do dendrites typically have a flat, tapering, 2-dimensional shape (leaf-like) rather than a conical, tapering, 3-dimensional ... | [
"I'm a little confused by the human body flair added here so maybe I can't contribute. Alloy solidification that I am accustom to shows 3 dimensional dendrites. Dendrite formation is typically driven by chemistry, crystal structure, and temperature gradient. I deal with solidification of steel alloys."
] | [
"Dendrites in the human body (that form synapses) are also 3-D, so the question is a little confusing."
] | [
"I came here to answer a much simpler question (as implied by the flair)... I'll try to answer both...",
"\n",
"I assume you are referring to dendritic morphologies like this.",
"\nSolvated zinc ",
" tetrahedrally coordinated, but I cant say more without knowing the composition of the alkaline electrolyte s... |
[
"Does gravity have any affect on rotation?"
] | [
false
] | It should not have one if gravity field is viewed as constant. But in space it might favor rotation in certain direction. Is there analogue of Newtons law for gravity for torgue? Sorry for improper English. | [
"Not in the Newtonian approximation, no. There are \"gravitomagnetic\" effects in ",
"general relativity",
", but they're extremely small.",
"http://en.wikipedia.org/wiki/Gravitomagnetism",
"http://en.wikipedia.org/wiki/Frame-dragging"
] | [
"I should point out that tidal locking doesn't mean that the Moon has stopped rotating. It means that the Moon rotates at the rate of one revolution per Earth day."
] | [
"If you're that close to a black hole, I'd imagine you've got a number of sufficiently urgent concerns that we can still call the frame-dragging effect relatively small."
] |
[
"As there are binary star systems, where two stars orbit each other, is it possible for a ternary star system to exist, i.e with 3 stars orbiting each other?"
] | [
false
] | null | [
"Yes, and the most stable form of a ternary system involves a binary system where a third star orbits the binary system, and is far enough away to where it could look at the binary system as a single gravitational object. If this is not the way the system is organized, one or more of the stars is likely to be flung... | [
"To add, the closest star system to us, the Alpha Centauri system, is thought to be this. Alpha Centauri A and B orbit each other while Proxima Centauri orbits around the pair. Proxima Centauri is believed to be orbiting the pair every 500,000 or so years. ",
"Edit: changed orbital period"
] | [
"The closest star to the Sun, ",
"Alpha Centauri",
", is actually three stars in this configuration. Alpha Centauri A and B orbit around each other, and Proxima Centauri, much smaller, orbits around the two. This actually makes Proxima Centauri the nearest star at the moment.",
"You can even get this in a mor... |
[
"Are our gas planets in our solar system almost a perfect sphere/ellipsoid?"
] | [
false
] | Or are there "bumps" in the atmosphere? | [
"There are bumps and structures at the highest parts of the atmospheres of Jupiter and Saturn. I dont know much about them but you can think of the bumpyness of clouds when you look down on them from above on Earth and it is somewhat similar for gas giants. Just on a larger scale and different structures due to the... | [
"Even with their gravity field?"
] | [
"Yes the fluid gets less dense as you get higher up so there is less mass to be affected by gravity. ",
"I cant find the picture anymore but there is at least 1 picture out there of the shadow cast by a cloud on Jupiter showing that there is depth. "
] |
[
"Do human women go \"into heat?\""
] | [
false
] | from Wikipedia " Recent research[1] suggests, however, that women tend to have more sexual thoughts and are far more prone to sexual activity right before ovulation (estrus)." | [
"One of the defining adaptations that gave rise to humans as we are now was the elimination of discrete periods of heat. A small peak in sexual interests is not going into heat, which is essentially turning on the female reproductive system.",
"May it be a small aspect of biology remaining from our heat-based anc... | [
"Strippers earn more money when they are most fertile.",
"http://mindhacks.com/2007/10/04/strippers-earning-potential-affected-by-hormone-cycle/"
] | [
". . .heat, which is essentially turning on the female reproductive system.",
"Being \"in heat\" is just a state of sexual responsiveness, timed to coincide with ovulation in order to maximize reproductive success. Some species may require copulation to initiate ovulation, but it does occur spontaneously in other... |
[
"What are the long term effects of positive pressure ventilation as opposed to the normal negative pressure used to inflate the lungs?"
] | [
false
] | null | [
"Usually the most common physiological issue with long term use is ventilator dependency. People who have been on this type of therapy for a while often have to be weened off of the ventilator once they are healthy enough to survive without it to prevent acute respiratory distress and/or failure. The most common ex... | [
"Another consequence to violating normal respiratory physiology is barotrauma, potentially leading to emhysematous changes in the lungs, fibrosis, and pneumothorax."
] | [
"Infectious complications are primarily due to the bypass of physical immunologic barriers such as a the trachea and the coughing mechanism. A major problem with chronic infections is the development of resistant strains of bacteria."
] |
[
"Is Hawking still correct?"
] | [
false
] | In , Stephen Hawking wrote, “Now at first sight all this evidence that the universe looks the same whichever direction we look in might seem to suggest there is something special about our place in the universe. In particular, it might seem that if we observe all other galaxies to be moving away from us, then we must b... | [
"Yes, Hawking is still correct. There is still no evidence either for or against the Copernican Principle. There ",
" models of cosmology that have a preferred center and which make the same predictions as a cosmology based on the Copernican Principle. We appeal to parsimony or some other sort of philosophy when ... | [
"The LTB cosmology is one such example. ",
"(Also, by \"big bang cosmology\", you likely mean \"FLRW cosmology\". The LTB cosmology is also a big bang cosmology, but the time since the big bang is not the same throughout all of space. An FLRW cosmology is isotropic about all points in space; an LTB cosmology is i... | [
"No. It is quite easy to determine whether you are at the preferred center in the LTB cosmology. For instance, Hubble's Law would not be true; it would not be the case that all galaxies are redshifted and seem to be receding."
] |
[
"Are some cells more greedy than others? Do some cells use more resources than their benefit to the organism?"
] | [
false
] | [deleted] | [
"Yes, this is what happens in cancer. Essentially, through mutation and selection, cancer cells have lost their \"restraint\". They consume nutrients and grow in a way that benefits the cancer cells (temporarily) at great cost to the host body."
] | [
"No, because the brain's use of energy is directly related to your most fundamental abilities to function."
] | [
"Exactly, so the word \"greedy\" would not apply to the brain, although the brain does use a lot of energy."
] |
[
"Is there a term or specific rule sort surrounding the ‘shortened grammar’ often seen on signage?"
] | [
false
] | Many signs and labels use a sort of ‘shortened grammar’ in which certain words such as ‘the’ are omitted where their use should be obvious. I can think of a few common examples off the top of my head, although I have seen some signage where many more qualifying words are omitted: “Do Not Enter [the] Building”, “Employ... | [
"The technical term for omission in linguistics is \"ellipsis\". The fact that utterances with ellipsis are understandable - i.e. that we can fill in the missing elements - informs us about how our brains process sentences, supporting the idea that language is parsed in abstract structures which exist independently... | [
"In some linguistic registers, rules for constructing valid utterances are more flexible. ",
"A ",
" is roughly the level of speech one uses in a given context. So before a court, a speaker may be exceptionally careful to sound precise, and a lawyer or expert may use a lot of legal jargon. But when drinking wit... | [
"ASL drops and combines words, too.",
"ASL should be understood as its own language instead of a \"code\" for English. Besides the obvious vocabulary difference, grammar and constructs are significantly different. ",
"Native ASL and Deaf students often have really rudimentary written English skills, to the poin... |
[
"In what sense is gene expression stochastic?"
] | [
false
] | I've heard many many times that gene expression is stochastic. What does this mean exactly? More to the point, is it just a statistical description of a process we don't know enough details about to describe more accurately, or is gene expression fundamentally stochastic (e.g. from quantum mechanical effect). | [
"All chemical processes are, to some extent, stochastic because they're all quantum mechanical. A better question to ask would be ",
" gene expression is \"truly\" stochastic; in other words, if you could \"rewind the tape\" on a cell and hit \"play\" again, so that every molecule has the same configuration as it... | [
"I'm going to play a bit of devil's advocate here, just because I've been asking some people whom I trust on this topic, some that study gene expression for a living, and I've still been getting different answers.",
"(1) The paper you gave specifically says that they mean stochastic in the statistical sense (ie. ... | [
"I'm going to play a bit of devil's advocate here, just because I've been asking some people whom I trust on this topic, some that study gene expression for a living, and I've still been getting different answers.",
"(1) The paper you gave specifically says that they mean stochastic in the statistical sense (ie. ... |
[
"What causes the intensely cold sensation when you drink water after you chew minty gum?"
] | [
false
] | I doubt the water actually gets physically colder, so why does it feel so brutally cold? | [
"Menthol",
" (found in mint plants) triggers the cold-sensitive receptors in the skin. It's sort of like the opposite of Capsaicin (found in chili peppers) which stimulates heat receptors."
] | [
"Half true, just correcting the mechanism. Menthol alters the proteins that sense temperature in our mouth, effectively lowering the temperature that illicit a cold response. ",
"Good paper in Nature: Identification of a cold receptor reveals a\ngeneral role for TRP channels in thermosensation. "
] | [
"Is there a reason that liquid causes the pain to magnify? Or is it simply because it spreads it throughout the mouth?"
] |
[
"How is memory related to intelligence?"
] | [
false
] | null | [
"Everything I'm going to write are only hypotheses so be careful, to be taken as a basis for reflection not as an answer.",
"The more elements a person is able to memorize, the more he will be able to do something new with these elements, to create, to modify, to bring out a new thought or a new way of solving pr... | [
"I would think that intelligence is the capability of doing things and invent interaction with unknown elements. Otherwise it's a memory thing."
] | [
"Really not a thing you should be agreeing or disagreeing with unless you only asked the question to affirm some belief you had."
] |
[
"When civil engineers look at cracks in the walls of a building, how do they know if the structure has been compromised?"
] | [
false
] | [deleted] | [
"Most cracks you will see in a building come from small displacements in the structure which are probably not dangerous, but produce a mismatch with the rigid materials used for the walls. What is important here is not the crack itself but make sure that these displacements do not become too large and are not cause... | [
"The other thing that you look for is whether the crack is recent/old, or moving/changing.",
"As far as age of the crack, this is mostly something that you have to figure out through inspection (does it look fresh? is it filled with old paint? does the concrete look weathered? etc...).",
"To figure out whether ... | [
"Here's an article about different types of cracks in concrete: ",
"http://www.gsa.gov/portal/content/112806",
"They have to put together knowledge of the type/ location of crack, with their understanding of how the structure is loaded and what it is made of. A lot goes into it."
] |
[
"What is the ping to the Curiosity rover?"
] | [
false
] | I presume it must have one, considering that it also must have an IP address. Just curious (pun not intended) | [
"Between 9~42 minutes round trip, depending on the orbital positions of the Earth in relation to Mars. The Rover sends it's signals to one of 3 satellites in orbit around Mars, part of NASA's deep space network, which then relay the signals to NASA's ground stations on Earth. Any form of network address would be no... | [
"Not germane to the original question, but it's worth commenting that Curiosity does have the ability to send and receive directly from the Earth without going through one of the Martian orbiters. (I believe the instructions at the beginning of each sol were planned to be sent directly, though I don't know if that... | [
"Sorry if this is pedantic, but NASA's Deep Space Network antennas are all ground based and do not include anything in orbit around Mars. It is the DSN antennas that are used to talk to those satellite or to the rover directly."
] |
[
"Can all animals suffer from muscle atrophy?"
] | [
false
] | It seems like some animals can have very strong muscles which they rarely use, say like a crocodile's jaw. Does every animal need to exercise to preserve muscle mass, or do some not have to? Are there muscles in the human body that don't atrophy? | [
"Bears have been studied because their muscles don't atrophy over hibernation.",
"http://www.asbweb.org/conferences/2007/425.pdf",
"http://researchnews.wsu.edu/health/74.html"
] | [
"Don't have an answer, but I'd like to add a question: How the hell does my cat maintain any muscle mass whatsoever, if the answer to the above question is \"yes\"?"
] | [
"Walking to the litter box, walking to the food dish, eating and drinking food, walking to the couch, clawing at your face...plenty of movement if you ask me. "
] |
[
"What is the 'false positive' rate of coronavirus tests? Is this causing the stall of decline of cases in the UK, or is there another reason we are stuck at 5-6k per day?"
] | [
false
] | null | [
"There doesn't seem to be an exact statistic on this, but for most tests the false negative rate is much higher than the false positive rate. For saliva tests there is actually about a 40% false negative rate for asymptomatic people. This is the closes thing to a real source I could find:",
"\"The number of false... | [
"The analytic performance of molecular tests (like PCR) is very close to 100% for this virus. In other words, if there is no virus RNA in a sample, less than 1% of the time the test will detect viral RNA.",
"The clinical performance is very difficult to test, and that's really what you're asking about. In other w... | [
"Or, it’s hard to get positives below 50,000/day when you’re doing over 1 million tests/day and not all PCR. Even with 99.5% specificity, you’d get over that. Clinical accuracy does not match the near 100% sensitivity and specificity on analytical samples."
] |
[
"When I eat something that is labeled 300 calories. Protien, Carb, or Fat--Does my body utilize 100% of those calories as energy/store it or is there wastage. And, would the calories be labeled differently if they were intended for an animal other than human."
] | [
false
] | null | [
"I'll only tackle your first question, since it hasn't been answered yet. There definitely is waste of energy at different times of metabolism. This doesn't mean your body is lazy or inefficient: waste is unavoidable. First of all, your feces are not \"calorie-free\", so your body only can consume part of the fuel ... | [
"Food calories are simply are not based on you or your metabolism (much), or any other human being, or animal. They come from lab measurements from over 100 years ago.\nConventional food energy is based on heats of combustion in a bomb calorimeter and corrections that take into consideration the efficiency of dige... | [
"That said, is there any measurable difference in the absorption efficiency between persons? So person A gets a full 100 calories from that piece of cheese but person B only gets 90?"
] |
[
"Is it possible to predict likely virus mutations in the wild by rapidly mutating the virus in a lab? (For example, predict the most likely future covid-19 variations.)"
] | [
false
] | null | [
"“Is it possible?” questions invite speculation and discussion, which are a poor fit for ",
"r/askscience",
". Questions based on discussion, speculation, or opinion are better suited for ",
"r/asksciencediscussion",
"."
] | [
"“Is it possible?” questions invite speculation and discussion, which are a poor fit for ",
"r/askscience",
". Questions based on discussion, speculation, or opinion are better suited for ",
"r/asksciencediscussion",
"."
] | [
"“Is it possible?” questions invite speculation and discussion, which are a poor fit for ",
"r/askscience",
". Questions based on discussion, speculation, or opinion are better suited for ",
"r/asksciencediscussion",
"."
] |
[
"Cardiac Question: In what manner is a 'rapid' or 'irregular' heartbeat dangerous?"
] | [
false
] | I was just thinking about this topic, and it seems that rapid (but regular) heartbeats from nutraceuticals is frowned upon and irregular heartbeats are frowned upon. In my field (dietetics) all 'heart' problems, and thus heart healthy foods, are just those that maintain circulation (reduce artherogenic build-up, regula... | [
"Thanks for the leads, will look into those two keywords."
] | [
"There are two main ways that an irregular heart beat, or arrhythmia, occurs.\n1. Damage to the heart muscle (myocardial infarct, cardiomyopathy)\n2. Pathologic pathways of electrical conduction",
"The danger of cardiac arrest arises when the heart is beating with an arrhythmia (specifically ventricular tachycard... | [
"SVT is ",
", tachycardia that occurs above the ventricles, either junctional or atrial in origin. Technically sinus tachycardia is an SVT, and sinus tach above 150 would be atrial tach, which can be difficult to distinguish from junctional tachycardia, hence the catch-all SVT.",
"SVT aren't as worrisome as VT,... |
[
"Regions in the brain?"
] | [
false
] | I've been reading up on neuroanatomy and I'm trying to get the regions straight but I've been having difficulty because of the terminology and whats a part of what and where and so on, I guess my questions are: I suppose that sums it up, I've looked through a lot but can't seem to make sense as to what is part of what,... | [
"Your question pretty much hits on why understanding brain anatomy is so difficult--regions are both distinct and not distinct, and many regions contain further subdivisions within them. For example, the cortex is thought to house the conscious thought and processing of the brain (language, planning, attention, mot... | [
"Depends on what you mean by region. Broadmann areas are defined by the structure and organisation of their cells. Another way of looking at it is by considering cortical and subcortical structures such as the thalamus, cerebellum, basal ganglia etc... some structures are within other structures, for example, the ... | [
"Thank you! I'm perusing this as we speak. Or type. And the examples are fine, I just need something to get me started on it and good resources, which I now have.",
"And you're not alone in the neuro-nerd category, I hope to be joining your ranks quite soon. I've already majorly geeked out in most other various n... |
[
"Could someone explain the relationship between spacetime and gravity?"
] | [
false
] | My initial understanding was that gravity somehow bent spacetime, but I'm not entirely sure how or what that even really means :P | [
"We know from relativity that how one measures lengths and times is, well... relative. Special relativity, the easy case, tells us these measures are related to relative velocity. But what happens when my velocity ",
" is different than my velocity ",
". I have a change in measure with respect to my previous me... | [
"The best book on this is Hartle's ",
". Simple title, brilliant book. You'll need to pick up a little bit of how Lagrangian and Hamiltonian formulations of physics work, but I think those are fairly straightforward concepts if you have a decent background in differential equations. Plus it has great pictures tha... | [
"This is a poor description because it still implies gravitation. I mean what's pulling \"down\" on the sheet, what's pulling objects towards \"lower\" parts of the sheet? You could just as easily represent a gravitational field (in the Newtonian sense) by this rubber sheet analogy and come up with the same result.... |
[
"How do we reach temperatures such as 3500 degrees Celsius?"
] | [
false
] | I was on the topic of tungsten for an irrelevant project, and wikipedia said that its melting point was 3422 degrees Celsius, and an even higher boiling temperature of 5555 degrees Celsius. What sort of process is required to reach such a temperature? Or are those numbers just based on predictions? | [
"Acetylene oxygene welding or cutting goes up to 3500 degrees, abd it is a commonly available tool. Plasma cutting achieves temperatures of up to 25000 degrees. Lasers can also be used for achieving very high temperatures.\nThese are only some ways of achieving high temps, and i think induction heating can too. Can... | [
"We can reach temperatures far hotter than that.",
"The fusion core ITER for example will operate at 150 000 000 K.",
"Just for reference: this is 30 000 times hotter than the surface of the sun. ",
"You can visit ITER's website in order to get some insight in the process.",
"Source"
] | [
"In addition to the heating methods that other people have mentioned, you can also play games with the pressure of the system to adjust the temperature. If the system has a fixed volume, then you can increase the pressure to proportionally increase the temperature."
] |
[
"Why does flies seems to like to buzz around/on our faces?"
] | [
false
] | From the point of view that flying around out face will get us irritated and more incline to kill the little bugger, why does they keep doing so? Plus, why are they sometimes really fascinated by our facial cavities (ears, nose and eyes)? maybe these aren't the cases for all flies, but a lot of the kinds I meet fit tho... | [
"Confirmation bias, you don't notice the other ones..."
] | [
"Could be earwax and the oily layer on top of they eye"
] | [
"sounds good, but what about other places like ears and eyes?"
] |
[
"Do non-PID Controllers Exist?"
] | [
false
] | It seems an odd question; whichever design method I use, I invariably get a PID controller, possibly with some filtering. My question, then, is why we must keep using the acronym PID and not just say 'controller'? Edit: is this something to do with it? I'm not sure I know what's going on exactly... | [
"Yes.",
"The most basic kind of controller is a ",
"bang-bang controller",
", of which a common example is the thermostat used in homes. There are also proportional and proportional-derivative controllers, which are like PID controllers, but lacking the integral and derivative parts, or just the integral part... | [
"From a letter to the editor in ",
" Magazine (Dec 2013):",
"\"As an engineer, I hope that someday very soon, we abandon Proportional + Integral + Derivative (PID) control algorithms altogether. Instead, I hope that we embrace a slight modification of PID that produces stunning improvements in performance: fast... | [
"Yes.",
"Feed forward controllers use a physical model of the system to predict the next state, and apply a force based on this prediction. This allows control system to handle non-linear forces like sliding friction. It is most useful if the physical system has predictable or easily measurable properties.",
"S... |
[
"How come chocolate milk expires several weeks after regular milk?"
] | [
false
] | I just bought a carton and it doesn't expire until August 18th, whereas the regular milk all expired by the 27th of June. I understand this isn't a very scientific analysis. | [
"Chocolate milk, with that much of a shelf life, would be produced using ",
"UHT milk"
] | [
"Do you know whether or not they were produced on the same day?"
] | [
"No, which is why I was saying it's not a very scientific analysis. I did look through all of the milk for expiration dates though and the latest the regular milk expired was the 27th and the earliest the chocolate milk expired was August 18th."
] |
[
"Can overweight people survive longer without food?"
] | [
false
] | I'm not biologist, but I am wondering about this. Can the fat be used as an emergency "food" supply, or does malnutrition mean that starvation occurs at the same rate. | [
"Yes, there is a famous example of an obese guy fasted who for over a year under medical supervision and lost most of his bodyweight. ",
"Abstract here"
] | [
"Yes they can, however they can soon run into vitamin deficiencies and other micronutrients that arent stored in fat. There was recently a story of a doctor who essentially helped a morbidly obese man (400+ lbs) lose a HUGE deal of weight by essentially starving him of all food, while providing vitamins and other e... | [
"Actually not super recent. The fast itself was conducted in the 60's and the ",
"case study",
" published in the 70's."
] |
[
"Where do hermit crab’s shells come from?"
] | [
false
] | I’ve heard a few times that when a hermit crab gets too big for its shell it just finds a bigger one and transfers. Where do the shells come from in the first place? | [
"They will often times kill and eat- or even just discard- a snail to steal its shell.",
"I've witnessed this several times in my reef tank.",
"One time, i put a golf ball sized Tiger Nassarius snail that cost me $19 into my tank. I'd had it in quarantine for 3 months, it checked out disease free so I moved it... | [
"They come from snails...",
"They don't wait until they are too big, they change the shell whenever they find a better one.",
"Shells also get reused by other hermit crabs. If a big hermit crab finds a larger and better shell, a bunch of smaller hermit crabs can upgrade to larger shells."
] | [
"Yes. I agree with this. Hermit Crabs are home scavengers. You can google images of them making homes out of anything. The doll heads are the creepiest homes, imo. It was also a big trend to keep them as pets in the 70s. Not sure if that’s still a thing."
] |
[
"How or could a small consistent charge of electricity affect the way cells communicate?"
] | [
false
] | null | [
"Can you clarify your question further? Are you talking about neurons and neurotransmission? Also, what did you have in mind for a small consistent charge? 5mV? 10mV, 20mV? "
] | [
"there are ion-pumps that work very hard to maintain the cell's resting membrane potential at ~-40mV. any change to this that you could cause (say by using a voltage clamp) could significantly alter a cells ability to send an action potential in one of two ways:",
"1) if it was made more positive (depolarized clo... | [
"Thinking around 10mV-20mV \nSo exactly what I’m asking is how would it affect the receptors around the body and mind. Would the constant charge of electricity adjust the way we process things in real-world in any way beneficial? Considering that the human body it’s self produces electricity what would happen if we... |
[
"Why do teenagers and children seem less affected by COVID than other age groups?"
] | [
false
] | Not trying to turn this into a should they get vaccinated argument. During the height of lockdown there was this argument that children and teenagers weren't coming down with those symptoms and getting as sick as adults. Shouldn't their immune systems be weaker since they haven't been exposed to as many things as a hea... | [
"I couldn't find a particularly detailed answer on this question, but childrens' bodies deal with a COVID infection differently to adults for a number of reasons. I can't answer the question with *specific* reference to COVID, but I can talk about some differences between kids and adults that are likely part of the... | [
"Yeah, they say it's rare. But I've been getting at least 2 MIS-C cases a week in children as young as 6 months. Just had a 3 year old die of a heart attack due to it"
] | [
"Multisystem Inflammatory Syndrome in Children (MIS-C)",
"Is this a new condition that has come to light with the pandemic? Does it potentially affect their lives beyond the effects of COVID-19? Why did it take until COVID to identify this condition?"
] |
[
"what makes 'drinking' tap water safer than the stuff you wash your hands with?"
] | [
false
] | I've always wondered how places with drinking water taps (usually bars and clubs) can differentiate between the different water used. is there actually a purifier or a better kind of piping that does make the water safer to drink, or is it just a way to have one sink that peopel crowd around for tap water? | [
"There is only one source of water, and unless you are in a third world country or drinking from a well, it is safe to drink. It depends on the business but some may have extra filtration on the faucets intended for drinking water. Usually these filters only effect the taste, since again, the water coming from the ... | [
"I think they also have extra aeration devices; water that is colder and has more dissolved oxygen typically tastes better. "
] | [
"In older systems, the non-drinking water is stored for a time in ",
"header tank",
", which is in an unknown condition, sometimes with a poorly fitting/no lid... Whereas the drinking water tap comes directly off the mains supply."
] |
[
"How do radio signals work?"
] | [
false
] | I'm writing my final in a creative lit class - and I won't bore you with self-advertising or such - but why I want to know how they work is because in the story, there are a group of people who teleport by attaching themselves to radio signals. Another main question I want to ask is how do signals drop, or what causes ... | [
"They work by oscillating electric and magnetic fields reinforcing each other leading to propagation (more detail in appendix A). I guess in your story what would be possible is for the people to convert to signals which then latch onto carrier waves. This is exactly how you receive the songs while driving in your... | [
"2 questions.",
"If traveling away from a signal source in a car, is the doppler effect negligible? ",
"Furthermore, how come the frequencies aren't more precise? For instance why do we use 95.5 instead of 95.52831?"
] | [
"Doppler effect: Yes, because it depends on your speed as a fraction of that of light. "
] |
[
"Could a small star orbit a really large planet?"
] | [
false
] | Last weeks question about a moon having a moon got me thinking. Is it possible for a star to orbit a planet? I'm assuming that most suns are the largest object in their system, but are all of them like this? Also on the same note, could a small star orbit a larger star? | [
"It would be extremely difficult for it to happen. First, everything orbits a common barycenter, so the sun does orbit depending on the earth's location (and this produces the wobbles we use to detect planets outside of our solar system).",
"Anyways, a star is simply a large chunk of matter undergoing fusion, tha... | [
"Theoretically it's not impossible, if you had a planet that is made up of elements that don't fuse (elements heavier than iron) it could be larger than a star and not become a star. But the chances such a planet forming naturally are immensely small.\nBut then again, the universe is really big, so it might exist."... | [
"Stars absolutely orbit each other in whats known as a binary star system and they're awesome. William Herschel first discovered them. A star, however, cannot orbit a planet because of the way stars and planets are formed. The star comes first and then makes the planets from leftover nearby materials and can only f... |
[
"How can you lose horsepower in a car?"
] | [
false
] | null | [
"Hi lukdboss thank you for submitting to ",
"/r/Askscience",
".",
" Please add flair to your post. ",
"Your post will be removed permanently if flair is not added within one hour. You can flair this post by replying to this message with your flair choice. It must be an exact match to one of the follow... | [
"Physics"
] | [
"‘physics’"
] |
[
"In theory would it be possible to keep blood \"alive\" with the right kind of equipment?"
] | [
false
] | I don't mean freezing it. I was thinking about how blood is a cell in our bodies but its independent (in a way) of other bodily structures, if that makes sense. Could a machine be created that could supply blood with whatever it needs to keep it alive? Does blood have a finite lifespan once its created? Does it need ox... | [
"The main cellular component of blood is the red blood cell, which if I understand your question correctly is what you would want to keep alive. These cells are responsible for gas exchange, i.e. bringing oxygen to tissue and bringing carbon dioxide to the lung. There are many other components to blood as well.",
... | [
"\"Blood banks store freshly donated blood for up to six weeks before it is considered outdated and thrown away. But some recent studies suggest that people who receive transfusions of blood older than two or three weeks may suffer adverse effects.\"\n",
"Studies Question Shelf Life Of Donor Blood"
] | [
"But they could be kept alive outside the body?! That's cool."
] |
[
"If you split a crystal and pushed the two pieces together would the lattice snap back into place?"
] | [
false
] | I'm sure it would require some energy and the particular symmetry would have an effect. Assuming no contamination . | [
"Whenever you split a crystal in the real world, the surface atoms will have dangling bonds, which is a ",
" high energy state. It will immediately find some way to lower that energy state, by either forming extra bonds with neighboring atoms, which creates an irregular crystal structure in the outer couple atoms... | [
"That is called ",
"cold welding",
" and happens with pristine crystal surfaces. In principle it can happen with a broken crystal (before an oxide layer forms), but my intuition tells me you'd have to get the alignment juuuust right."
] | [
"That is very interesting. Is the problem with dangling bonds always present or are there some crystal arrangements (cubic, tetrahedral etc., I'm not very familiar with the terminology) that can be cleaved cleanly in any or some planes?",
"This question is highly speculative, but I'm interested to know if it is t... |
[
"Why do different materials sound different?"
] | [
false
] | Since sound is just a bunch of oscillations in pressure, shouldn't two different materials with the same mass and surface area create very similar pressure oscillations - and therefore similar sounds? Obviously though, if you drop a rock and piece of metal you get two very different sounds. | [
"Imagine the sound that a square sheet of steel makes when you tap it with a fork. ",
". When you tap it with the fork you create a little deformation right at the spot the fork hit. Steel has some decent elasticity, some springiness and stiffness to it, so if you were to zoom in with a microscope, you'd see some... | [
"Materials have different properties, densities, and atomic compositions. Since the atoms they are composed of have different masses, they oscillate differently, which causes the oscillations to have different frequencies, which produce different sounds. "
] | [
"This. This wiki page has a good visualization and more info on this matter. ",
"https://en.m.wikipedia.org/wiki/Phonon"
] |
[
"What factors determine whether something (event, occurrence, experience, etc) makes it into our memory?"
] | [
false
] | We obviously don't remember everything. There's got to be some system of separating the wheat from the chaff. So what determines what makes the cut and gains admittance to our cranial repository? | [
"There are probably multiple mechanisms and we don't understand them all yet, however one mechanism is fairly well understood. ",
"We generally remember experiences that cause strong emotional reactions: earthquake, car accidents, deaths, etc. This works through stress hormones. Particular emotional reactions le... | [
"In simplest terms, it's determined by how important a certain event is.",
"Your mind holds everything that you see in short term memory - these memories, like the face of someone you don't know, could last anywhere from 20 seconds to a minute. After that, your short-term memory starts to taper, and you'll start ... | [
"Does that mean if I make a drug that mixes epinephrine (or cortisol) and some kind of \"emotion enhancer\", I've created a memory enhancement drug?"
] |
[
"Why does opening both the window and the door make a room so much colder than just opening the window?"
] | [
false
] | Whenever I just open the window in my room, there is a slight breeze, and not much more. If I also open the door, the room gets significantly colder, as if there were some kind of vacuum effect. It probably has something to do with equilibrium, but can someone clarify why this happens? | [
"I don't know how your room is set up but I'm guessing it's just a matter of airflow. If you have a door open as well it is easier for air to flow through the room to cool it rather than just trying to enter / exit through the window and mix. "
] | [
"It is sort of like an issue of pressure. If you only have a window open if air blows in it doesn't have anywhere to go really other than compress. If you have the door open also it can sweep through cooling more effectively. "
] | [
"it doesn't have anywhere to go really other than compress",
"Well, it probably flows in the room through the lower half of the window and out of it through the higher half. But still, less efficient than opening a door too."
] |
[
"Why can't we synthesize Antibodies to treat Viruses?"
] | [
false
] | I don't know a ton about biology and chemistry seeing how I am studying physics. Why can't we take blood from a patient who successfully generated antibodies for a virus, isolate those antibodies, synthesize replicas and use them to treat new patients? | [
"Making a complete antibody is quite complex, even in today's time. For pharmaceutical companies it is usually much easier to look into other ways to vaccinate, like with dead viruses to make the appropriate immune response. It may still be relatively complex to do it, especially with viruses that mutate fast (like... | [
"There are many problems with your suggestion's details, but in the big picture it's not only possible to do this, but routine. ",
"The way it's actually done as a rule is to immunize mice with the agent, under controlled conditions; when the mouse has made antibodies (which are functionally the same as a human... | [
"That was one of the most thorough answers ever. Thanks. That explained quite a bit"
] |
[
"How are we utilizing quantum mechanics in the pursuit of technology?"
] | [
false
] | I think my question is more basic than it sounds. I understand HOW we use it, entanglement, superposition, etc. What I'm wondering is how we even get there! Atoms themselves are so incredibly small; how do we go about manipulating electrons and fundamental particles? What kind of equipment or technology is necessary? | [
"One way to include quantum mechanical effects in otherwise bulk materials is to include very thin layers of another material. ",
"If you were to heat a bit of material in a vacuum chamber to the point where it beings to sublime, atoms from that material fly off and may stick to whatever they hit. If you do that ... | [
"I do research in spectroscopy, particularly electronic/laser spectroscopy. The laser alone represents some amazing advances in quantum mechanics that allowed us to construct it in the first place. The system I study are semiconductor nanocrystals, often referred to as quantum dots (QDs).",
"QDs are remarkable ... | [
"Photonic quantum information devices are probably the easiest. For polarization-entanglement you can use ",
"spontaneous parametric down-conversion",
" in a nonlinear crystal. It is not very complicated and merely requires a strong laser to pump the crystal and a suitable crystal plus a bunch of generic optics... |
[
"When I stretch a piece of red plastic wrap over the end of a flashlight and turn it on, what is really happening to the light?"
] | [
false
] | null | [
"The \"white\" light coming from your flashlight is leaving the bulb and traveling towards the red plastic. White light is of course all colors of light traveling together. ",
"When this white light hits the red plastic, the part of the light that is red continues through, but all of the other colors of the rai... | [
"You got it a bit backwards. Grass, just like most other things with green chlorophyll in it absorbs most of the light in the visible spectrum. Its absorption minimum is around 550 nm, which gets reflected. That reflected light looks green to our eyes.",
"Now, if you take a photo of the grass and print it on a st... | [
"You got it a bit backwards. Grass, just like most other things with green chlorophyll in it absorbs most of the light in the visible spectrum. Its absorption minimum is around 550 nm, which gets reflected. That reflected light looks green to our eyes.",
"Now, if you take a photo of the grass and print it on a st... |
[
"As an enveloped virus, why can COVID-19 survive on surfaces for so long? From my understanding enveloped viruses must stay wet to remain infectious and are sensitive to environmental changes"
] | [
false
] | null | [
"Not to flip the question back to you, but what do you define as \"for so long\"?",
"Non-enveloped viruses, such as norovirus, can survive on surfaces for weeks, if not months. In contrast, enveloped viruses survive for hours (days depending on type of surface). Comparing the two, enveloped viruses such as COVID-... | [
"Also - that a virus DNA has been detected on some surface doesn't mean that the virus is actually \"alive\" (as much as a virus can be considered being alive), viable and capable of causing an infection. ",
"Many of the studies, especially the ones with the large number of hours/days for the coronavirus that hav... | [
"It only survived that long in optimal perfect conditions. And the longer it’s there, the fewer there are. If someone says it survives 72 hours, that doesn’t mean 100% of it survives that long, that’s when the last remnants die off. Friction and environmental changes do effect how much of the virus is still alive v... |
[
"Reddit do you have any examples of bias within science?"
] | [
false
] | null | [
"This might be an interesting example of bias that was eventually overcome."
] | [
"Thank you"
] | [
"There's plenty of bias in science. It's actually harder to find an example where bias ",
" exist in some form or another. The point is that the process (repeated peer review and duplication) is designed to minimize the ",
" of bias. That's the beauty of the scientific method - it can succeed in a relatively un... |
[
"Do COVID-19 vaccines prevent Long COVID?"
] | [
false
] | There have been reports that COVID-19 can for some leave lasting damage to organs (heart, lungs, brain), even among people who only had minor symptoms during the infection. Since some of the vaccines, notably the one developed by Oxford-AstraZeneca, report ok-ish efficacy in preventing symptomatic COVID-19, but very h... | [
"I wouldn't confuse 90 plus percent efficacy with only okay results. The bottom line is the vaccines, even after only the first dose, drastically reduce your likelihood of getting covid-19 of any type, long, asymptomatic, death, etc.",
"The data are very clear that the vaccines are highly effective and highly saf... | [
"Long covid is just a term for the side effects of residual damage from the virus and resulting inflammation. This could be damage to the lining around the heart, lung damage that reduces lung capacity, neurological damage, or damage from blood clots. In extreme cases, people have even had limbs amputated. ",
"Lo... | [
"Long covid is just a term for the side effects of residual damage from the virus and resulting inflammation. This could be damage to the lining around the heart, lung damage that reduces lung capacity, neurological damage, or damage from blood clots. In extreme cases, people have even had limbs amputated. ",
"Lo... |
[
"Most star systems are binary. Is Jupiter a sun that never 'ignited'?"
] | [
false
] | In 2001 or the sequel (or both) Jupiter gets turned into a sun. Was Jupiter just a sun that didn't have enough mas to fire up? | [
"I'm not sure if there's any more recent research, but at least as of about 2006, astronomers had concluded that, in fact, most stars are singletons, not binary or higher. You can see articles on this ",
"here",
" and ",
"here",
". The studies showed that while most bright stars were in multiple star syst... | [
"The radius could easily stay the same, just as it could shrink or expand. ",
"Mass is not always correlated with radius. Keep in mind that black holes are collapsed stars. These entities are single points with densities approaching infinity. Similarly, you can have red giants that are overall less dense than the... | [
"Just to add: \"bigger\" here means more massive. Jupiter actually has a very similar radius (if not a slightly larger one) to a brown dwarf tens of times more massive than it."
] |
[
"Does the spin of a ball reverse upon hitting a wall?"
] | [
false
] | I play racquetball once in a while, and came up with this question. If I give the ball a spin, will it continue to spin the same way on its way back or will it spin differently? Thanks! | [
"Not necessarily. On a frictionless ball this would be true, but in the real world you can get a ball to change its spin when you bounce it. ",
"Basically, rubber balls have both friction and elasticity. When a bouncing ball hits the ground, it compresses and acts as a spring. Some energy goes into the ball a... | [
"This is dependent on the materials used and the friction between the two. In a perfect bounce. All kinetic energy is converted into elastic potential energy as the ball hits the surface, then is reconverted back into kinetic energy. Now if a ball's spinning, those mechanics come into play, albeit a little differen... | [
"It depends on the angle at which it hits the wall. That said, I'm curious as well for the case of a head on collision.",
"And even for a head on collision, it is going to depend on the properties of the ball. If the ball weren't elastic in any way, certainly no. But racquetballs are not perfectly ridgid, whic... |
[
"Energy: What exactly is it? How would you describe it physically?"
] | [
false
] | How would you physically describe different types of energy e.g. Energy produced from respiration in body cells, energy in EM(Electo-Magnetic) waves? How does energy made from respiration enable you to make your muscles work? Thank you for any answers. | [
"Energy: What exactly is it?",
"It's a (usually) conserved quantity that can be calculated from measurements on a system, and becuase it is conserved, it can be used to calculate/predict new measurements when the system changes or interacts with another system. This makes it very useful to know! The same is tru... | [
"There really isn't a satisfying definition without understanding advanced classical mechanics. Until then, you have circular definitions like \"energy is the capacity to do work.\"",
"Energy is something that is conserved when a system doesn't change if you move it forward or backwards in time. This comes from s... | [
"Etymology is not the same as definition though. Atoms are sliceable."
] |
[
"Why can we see so far into the past?"
] | [
false
] | Why can we see so far back into the past? This has always puzzled me. If we are expanding then I would think any light emitted long ago must have already passed the earth. Since we are now able to see roughly 12 billion years ago, I am obviously missing something. My Google and Reddit searches have failed me. There ... | [
"I think you may be confused about what the expanding universe actually looks like.",
"If by an \"expanding universe\" you picture a bunch of stuff moving away from each other, then indeed you would imagine that there would be some sphere around 13 billion light years in radius, and at the edge would be the first... | [
"Fun fact: The term \"Big Bang\" was actually coined ",
" by someone who was mocking the idea. The name stuck. Though \"Horrendous Space Kablooie\" has been rising in popularity in recent years.",
"In fact, it was neither big, nor a bang."
] | [
"light we see that is 13 billion years old came from a source 13 billion light years away.",
"This is not true. Read up about the expansion of space."
] |
[
"Why isn't it possible to create a monopolar magnet by just creating a ball of stick magnets with all the same pole pointing inwards/outwards?"
] | [
false
] | Wouldn't that create a magnet which has the same pole on all sides? For illustration i tried to make a paint sketch: Why would the magnetic field created by those two be different? Wouldn't both magnetic fields just radiate straight outwards? | [
"Maxwell's equations, specifically div(",
") = 0, say this is not possible. In fact, the magnetic field of the (ideal) configuration that you propose would just cancel entirely and be ",
" everywhere. (If ",
" is spherically symmetric, then ",
" = B(r)",
" and the flux across a sphere of radius ",
" is ... | [
"It won't work. Individual magnets would have field lines between them. Even if you could make a hollow sphere which was radially magnetized, you can't create a monopole. The fields of magnets on opposite sides cancel each other. There is no field inside or out. ",
"Source"
] | [
"The \"SN\" magnets on the left side would also have an effect on the field on the right side, cancelling the \"NS\" magnets there, and vice versa. Same for all other regions. As result you only get small irregular fields from the not perfectly symmetric arrangement of magnets.",
"An analogy with electric charges... |
[
"Why doesn't the speed affect the amount of work done by friction?"
] | [
false
] | null | [
"My confusion comes from believing the an increasing velocity would increase the distance traveled by the box thus increasing work done. Can someone explain to me why this isn't true?",
"That's only true if the initial velocity is >0 and F_f>F_g (kinetic friction is causing the box to slow down), in which case if... | [
"It would travel farther if the force due to friction was greater than the force due to gravity, and hence it stopped moving eventually. There's two other possible cases where the object continues to travel indefinitely."
] | [
"It would travel farther if the force due to friction was greater than the force due to gravity, and hence it stopped moving eventually. There's two other possible cases where the object continues to travel indefinitely."
] |
[
"What happens to the lungs after death?"
] | [
false
] | Do bodies really exhale like on TV? Can you die with a full breath inside your lungs? If you can die with air inside, how long does the remaining air last? Does your diaphragm need to move to empty the lungs? Edit: Thanks to everyone who answered! Follow up question(s): what happens when someone dies of smoke inhalatio... | [
"I will give you an example from my experience as a nurse. When turning/moving a person who has recently died, yes you can hear them exhale. Maybe the movement changes the pressure in the chest or abdomen. Let me just tell you that the first time I heard it I freaked out a tiny bit."
] | [
"Worked as a mortician for a few years during my apprenticeship as a carpenter (in small villages in Germany usually the carpenter doubles as mortician) and the first time moving a dead person was pretty upsetting.",
"If you lift the body on both ends it bends in the abdomen area which compresses the lungs and fo... | [
"Does it make a sound like a sigh or is it just a rush of air?"
] |
[
"Why isnt space super bright even though The Earth is bright."
] | [
false
] | null | [
"Astronomy"
] | [
"Astronomy"
] | [
"Things appear bright because photons are entering our eye (after bouncing off of something or straight from the source). There is (practically) nothing in space, so it is black. When we look at sun, photona emitted from the sun hit our eyes and we see light. Photons bouncing around in our atmosphere eventually rea... |
[
"Can plants get \"cancer\"?"
] | [
false
] | They are made out of cells and exposed to UV rays nearly all the time. So why shouldn't the UV rays ionize their cell nucleus and corrupt the DNA? | [
"Any complex multicellular organism can be suseptible to defects in cell proliferation causing individual cells or groups of cells to develop abnormally. In animals, these defects lead to tumour formation and cancer and plants develop tumours too which can be detrimental to how they function or develop. One crucial... | [
"A side note: tumors on trees are also known as \"burls\", and the wood that comprises them is called burlwood. Because tumors are basically unregulated growth, they generally have a ",
"very irregular grain",
", which actually makes it superior to normal wood for certain purposes. For example, burlwood is far ... | [
"I always imagine DNA as being a \"code\" which says \"put the next cell here, the next here, etc.\"",
"It's more like a complex network of interconnected chemical mechanisms running independently in each cell. There isn't a \"next cell wall here\" overseer imposing high-level order so much as there are many sel... |
[
"Does the force of ejaculation influence the probability of impregnation, or is this only determined by the swimming speed of individual sperm cells?"
] | [
true
] | null | [
"Right, I see that most folks have decent answers but were kinda 'half-answers'. I'm hoping to provide some simple, complete and conclusive answer considering I just did a thesis on this.",
"Here's the first part of the answer: ",
"The second part of answer, we'll explore what exactly determines probability of ... | [
"I got so desensitised to semen/sperm after the thesis that i found wearing gloves to handle donor sperm too much of a hassle.",
"That old wives tale, as you rightly put it, is an old wives tale.",
"We tell the women who receive embryos or intrauterine inseminations to just do whatever they like and move howeve... | [
"Seems like they are an assortment of potential research topics here that could garner an Ig Nobel Prize. ",
"https://www.improbable.com/ig/"
] |
[
"Why when you chop an ant's head off, both, its head and torso keep moving separately for a while, but when something similar happens to a mammal, it immediately dies?"
] | [
false
] | [deleted] | [
"Newborn mice continue to move for up to about 30 seconds after they have been decapitated. If you squeeze a paw on the body after they have been decapitated, the body will respond similarly to how it does before it was decapitated. The movements are all likely just reflexes.",
"Source: working in a bio lab do... | [
"It turns out, most insects have nerve-groupings in their bodies that can control limited functions. I cut the head off a wasp once by accident and I noticed it could still walk, beat it's wings, etc. It couldn't fly, that's a higher level function that needs a brain to control it. So, it's kind of like the nerve r... | [
"It has a lot to do with the structure of the nervous system as well as the means of providing oxygen to the nervous system. Insects are invertebrates and have no central nervous system; it is distributed throughout the body. All mammals have a central nervous system which includes a spinal column and the brain (of... |
[
"Two Part: 1st - Which produces more carbon - car or bicycle rider - and what is the difference in the carbon that is emitted and possible impact to global warming? 2nd - What has the highest impact of road stress/damage (weight, contact area, total force applied to road, points of contact, speeds)?"
] | [
false
] | This got me thinking (for a TL:DR, there's a congressman who argues that cyclists are causing more impact on the environment due to their increased CO2 output and are damaging the roads and should be taxed proportionally). First, is there any real difference on the carbon emissions between the car and the human riding ... | [
"First, is there any real difference on the carbon emissions between the car and the human riding a bicycle (quantity/quality/impact to environment etc.)? ",
"Without trying to be condescending... how is this even a question?",
"Assuming a male ride, bicycle rider + bike + gear is going to weigh around 200-250 ... | [
"One minor correction: \"pounds of pressure\" is an inaccurate term. You're probably thinking of PSI, or \"pounds per square inch\"."
] | [
"One minor correction: \"pounds of pressure\" is an inaccurate term. You're probably thinking of PSI, or \"pounds per square inch\"."
] |
[
"Is the digestive system's time to absorb energy dependent on the amount of new food pushing previous food through the system, or is the timeframe relatively constant?"
] | [
false
] | For example, take 4000 calories worth of donuts. If they're consumed and immediately followed by a low calorie high bulk 'meal' of indigestible fiber, would the donut meal be less absorbed compared to if the donuts were eaten and followed by a period of fasting? | [
"Average calories of a Doughnut: ~250",
"Are you saying that eating 16 doughnuts is an implausible act for 1 person over the course of a day? ",
"High cal diets for body builders can range as far as 16,000cal/day consumption. That 4000cal doughnut binge would then only account for 1/4 of daily intake. ",
"You... | [
"There would be very little difference.",
"The digestive system does not work in a perfect linear fashion.",
"Food goes in, and is mixed together with other food in the stomach/intestine.",
"The digestive system would extract close to the maximum amount of energy in both cases."
] | [
"IIRC, sympathetic and parasympathetic system activity would make a difference. Basically, if you are stressed out (distress OR eustress - your brain doesn't know the difference really), your body shuts down digestion. ",
"The body also takes different amounts of time to digest different types of foods like prot... |
[
"Do bird's nests get reused?"
] | [
false
] | null | [
"Yes they do, I could walk outside and take a picture of a Kookaburra nest which is made of mud. It's halfway up a gum tree on the edge of our property. It's been there for at least three years and probably longer. Not sure if they use it every day or just for nesting etc"
] | [
"Some birds, like blue jays, will go so far as to kick out eggs in nests and take them over.",
"So to answer your question, yes, but often times, they won't be useful after the migratory season because they would have not been maintained and would have decayed during that time."
] | [
"Bald eagles re-use their nests. They can get huge as they keep building and sometimes the tree breaks from the weight.",
"I live near the Mississippi and this gas station owner hated this pair of bald eagles that built a nest in a tree next to the station. It was popular for everyone who drove by it but this g... |
[
"Why do particles decay?"
] | [
false
] | Also what is the difference between "radioactive" decay and say the way carbon decays (I'm thinking of they way archeologists date their digs). | [
"There are two competing forces in the nuclei of an atom 1) The Coulomb force (electromagnetism) which pushes protons apart and 2) the nuclear force (strong interaction) which pulls neutrons and protons together. In some atom configurations one force is stronger causing the atom to be unstable and decay. ",
"Radi... | [
"Curiosity sated!! Thank you."
] | [
"Follow-up question to your great answer: What would make one force stronger than the other in unstable atoms? Also, decay caused by a stronger Coulomb force makes sense to me, as a repulsive force, but how does having a stronger nuclear force than Coulomb force lead to decay? Wouldn't that just cause the protons a... |
[
"Why is the thruster on the X-37B off center?"
] | [
false
] | null | [
"If the outside of the craft is symmetrical then it is likely that I the weight on the inside is not evenly distributed. A craft that is heavier on the right becomes harder to \"push\" on the right and will then turn in that direction. Applying more force on the right than the left side (an off center rocket) will ... | [
"The thruster you see is only useful in space (it's a glider in the atmosphere), where the aerodynamics of the ship really don't matter, only the mass of the machine, the center of the ship when you take in mass is right over that point no doubt."
] | [
"But if the COM is off-centre the aerodynamics will also have to compensate for this, right? This would imply that the internals were arrange prior to the design of the airframe. This doesn't seem like an optimal way to go about designing an aircraft, so there must be a good reason. Is it designed for a specific ... |
[
"Can we digitize smells yet?"
] | [
false
] | null | [
"It doesn't quite work the same way. Your visual and auditory senses work by interpreting waves of energy. Energy is something we know how to create, or transfer rather. However smell is not quite the same. Smell works by receptors in your nose picking up on the presence of molecules. If we were to artificially rec... | [
"very true indeed. I guess i figured with the idea of recording the \"play back\" option would be implied. But i do see that I've made a mistake."
] | [
"I think you answered without reading the rest of his question. His intentions were about \"detecting\" smells, not creating them."
] |
[
"Would nuclear fusion reactors have a more destructive explosion than a nuclear fission reactor or is it the other way around?"
] | [
false
] | null | [
"Fusion reactors are much less prone to explosion than fission reactors. And neither can undergo a ",
" explosion. When fission reactors have exploded in the past, it has been due to chemical combustion reactions and/or buildup or large gas pressures in confined spaces."
] | [
"So fusion reactors can not explode no matter what?"
] | [
"Other than some kind of issue with the cryogenics, that's correct. The plasma can't explode."
] |
[
"What do we know about what exists beyond the observable universe?"
] | [
false
] | I apologize for the wording of this question(or if it's been asked before), and realize it might be confusing, so I'll try to explain... From what I know, the observable universe is defined as all that we can possibly see from around us, due to the distance light has traveled since the spawn of our universe, with us in... | [
"I read an article some time ago, talking about how we can somewhat study what's beyond the observable universe. In the article, it talked about studying things near the edge of what we can see, and comparing how we assume things such as gravitational forces should affect them, compared to what is actually happenin... | [
"By analyzing CMBR, the topology of the Universe has been fairly well determined to be flat (i.e. no lines which start off as parallel will ever diverge or intersect). This also means that the Universe would be infinite. Furthermore the Universe that we can see is extremely isotropic and homogenous, in other word... | [
"Yes, gravitational waves are theorized to travel at the speed of light in general relativity, which means if an event occurs that changes the gravity of a thing (such as a supernova), you won't see any changes until the gravitational waves propagate out to you."
] |
[
"Can anyone help identify this object? We think it is a model of a 5 dimensional cube, but we have no clue of the usage!"
] | [
false
] | I am talking about object. It is currently placed at Delft University of Technology in the Netherlands. There has been a post on there website about it and they aren't sure what its exact properties are. This post draw my attention as a student and I thought that might know what it is. This 'cube' was use from 1950 ~ 1... | [
"The same way you drav a 3-dimensional cube on 2-dimensional paper. Aspects will be lost, but it is not a useless representation.",
"EDIT: Hey guys. You are not supposed to downvote this guy. Question, AND WRONG ANSWERS that encourage good discussion should not be downvoted. Go read it yourself: ",
"http://www.... | [
"I'm not exactly sure how you can represent 5 dimensions with a 3 dimensional object. On another note, to even call this a cube is rather odd."
] | [
"It's simply a map of the connections between the vertexes. When you draw a cube on paper, you put down 8 vertices (2",
" ), 12 edges. Each vertex has 3 connections.",
"To represent a 5-dimensional object, you would write down 32 vertices (2",
" ), each with 5 connections to other vertices. There would be 80 ... |
[
"Rocket Science - How Exactly Does Thrust Work?"
] | [
false
] | Question about Rocket Science I’m probably doing a presentation on rockets for kids, using balloons as an analogy. Anyways, I began to wonder what the exact action-reaction is that causes the rocket to move. For instance, when I jump, I’m pushing against the ground. But what is the rocket fuel ‘pushing against’? Many s... | [
"The easiest way of conceptualizing how a rocket engine works is by imagining you are wearing ice skates and standing on ice, while holding a few bricks. If you throw a brick away from you really hard, you will start moving backwards.",
"Now imagine you have billions of bricks, and you're shooting them out with, ... | [
"Thanks for the response! I did find this a bit confusing though, for similar reasons. i.e. why does throwing the brick move the person back. but I guess the person is pushing on the brick when throwing it, and the brick is 'pushing back' before it exits the person's hands. ",
"either way, very much appreciated, ... | [
"Alright, here's an explanation that relates more to the underlying physical principles: at the core of the brick-throwing idea lies the conservation of momentum. For our purposes, momentum is simply mass times velocity. According to the momentum conservation principle, the momentum of a system must remain constant... |
[
"Researchers were able to speed light up to 30c. How is this consistent with special relativity?"
] | [
false
] | From : [The authors] demonstrated they could speed a pulse of light up to 30 times the speed of light, slow it down to half the speed of light, and also make the pulse travel backward. I realize that the speed of light is dependent on the material it travels through, but my understanding is that nothing can ever go fas... | [
"You can manipulate the properties of the medium to change the group velocity from c to something less than c (“slow light”), something greater than c (“fast light”), or basically zero (“stopped light”).",
"This article is about increasing the group velocity above c, so fast light.",
"But this doesn’t cause any... | [
"Well \"light is moving faster\" doesn't have a well-defined meaning, as there are multiple different ways that you could define the \"speed\" of the wave. And furthermore, each of those measures of speed is in principle frequency-dependent, and a pulse of light is never purely monochromatic. So different component... | [
"Why would that be the case? If light is moving faster, surely the pulses could be interpreted faster as well? I'm just a curious layman."
] |
[
"Are there any phages for viruses like there are for bacteria? (i.e. bacteriophages)"
] | [
false
] | I was wondering if there are any phages for viruses like there are for bacteria? Is there a way to create phages to kill viruses as a form of vaccine? | [
"The closest thing to this would be a ",
"virophage",
", but virophages require coinfection by their host virus; that is, they secondarily infect the cell already infected by their viral target, at which point their activity inhibits the activity of the initial infectious agent. Virophages couldn't simply infec... | [
"It's highly unlikely (maybe even impossible) for a viral phage to exist. Viruses reproduce by taking advantage of the host cell's ability to create proteins. A virus doesn't have the capability to produce its own proteins, so a virus that infects another virus wouldn't be doing much, except giving that virus its g... | [
"Thank you for humoring me with this!"
] |
[
"Do volcanic islands preserve fossils in the same way as sedimentary rocks? If not, how do paleontologists reconstruct the evolutionary history of organisms on volcanic islands?"
] | [
false
] | To be more specific, are there well understood evolutionary histories of the animals native to the Hawaiian Islands or Iceland, for example? | [
"Yes they (can) do, because volcanic islands can host depositional environments for sedimentary rocks. Just because an island has a volcanic origin does not mean that sedimentary rocks are unable to form. Many volcanic islands in the tropics will host carbonate reefs that record fragments of the island's palaeontol... | [
"I really appreciated the word \"volcaniclastic\". I hope to use it soon.",
"Thanks"
] | [
"Geology has a lot of good words. Carbonate classification schemes allow you to create some wonderful terms such as biooopelintrasparite (which would be a carbonate rock with skeletal grains, a kind of carbonate grain called an ooid, grains of carbonate mud, and fragments of local rock that have been washed in, all... |
[
"What is the exact time on the solstice at which the North Pole is pointed most directly away from the Sun / the Earth is furthest from the Sun?"
] | [
false
] | null | [
"Winter ",
"solstice",
" this year is December 21st, 11:12 am, UTC.",
"Earth is ",
"furthest from the Sun",
" on 3rd of July. Don't have the time of day for that but I'm sure you could find it somewhere if you really want to."
] | [
"...and that seasons have to do with the angle of solar energy through the atmosphere, not with orbital distance from the sun."
] | [
"It is a myth.",
" The urban legend says you can do it on an equinox, but actually, you can balance an egg on its tip any time of year. The earths gravity doesn't alter depending on it's tilt. :/",
"Although, technically it ",
" true. You ",
" balance an egg on it's tip on the solstice. just nothing exclusi... |
[
"What happens when I jump inside a space centrifuge?"
] | [
false
] | Let's say it's a fairly low-acceleration centrifuge, so I'll be able to jump quite 'high'. I preserve angular momentum and velocity, but where do I land? | [
"You would land most likely face first due to the rotation of the floor around your body as it floats during the jump. If you jump straight up head pointed at the center of rotation, your body still maintains its angular momentum and will travel along with the floor. This sounds fun though."
] | [
"Due to conservation of angular momentum, a jump(reduction in radius) would result in an increase in velocity. So it would seem like you rush ahead of the floors rotation. Similar if you dropped something, it would be swept backwards relative to the floors rotation.",
"This effect would no doubt make any vertical... | [
"If the radius of the centrifuge is large (I'm imagining something like an ",
"O'neill cylinder",
"), so that you don't cross the axis of rotation, it's fairly simple.",
"You will experience an acceleration a = 2v X Ω, where v is your speed jumping up (remember this is negative because you are jumping inwards... |
[
"Would each of my sperm result in a different baby? How different?"
] | [
false
] | I'm assuming each of the little sperm is different in some way but they're all mine, so varied versions of my code? | [
"due to genetic recombination its actually even higher than that."
] | [
"and with mutation, it's even higher. "
] | [
"1 / (0.5^23) = 8 388 608\n",
"8.3 million different combinations"
] |
[
"Do extremely loud sounds (150 decibels) at frequencies beyond human hearing (21kHz or 10Hz) still cause hearing damage or loss?"
] | [
false
] | [deleted] | [
"Yes. Ultrasonic sounds (above 20kHz) can cause some hearing damage but only from a prolonged exposure. At lower subsonic frequencies can cause your eyballs to vibrate making it difficult to see or focus. With rising amplitude sounds become more dangerous regardless of frequency. Above around 200 db sounds can caus... | [
"Above around 200 db sounds can cause fatal haemorrhaging and rupture of some tissues inside the lungs",
"Before that point, at around 195dB 'sound' ceases to function as a typical wave and turns into a shockwave."
] | [
"The limit before you clip the waveform due to drawing vacuum \non the lower peak and it becomes more of a shock front is ~194dB"
] |
[
"Do photons and quarks interact?"
] | [
false
] | I was thinking about atoms, and it occurred to me that the electron cloud is essentially shields the nucleus from photons. I wondered, though, what if the atom had no electrons, perhaps just a proton. Would there by any interaction between a photon and the quarks, or would they not affect each other no matter how close... | [
"A good rule of thumb (and by that, I mean, the rule itself) is that photons can directly interact with anything that has an electric charge. "
] | [
"Yes they do.",
"A stylized picture of the Feynman diagram"
] | [
"Thanks! Quantum mechanics never fails to surprise."
] |
[
"Are there any elements in the earths crust which are anomalously abundant?"
] | [
false
] | Speaking of the types of planets which are similar to earth, is there more or less gold, for example than there should be according to our current models of how a planet forms? ****Could there be a planet out there with abnormally high deposits of a certain mineral or element? I know there’s asteroids out there that co... | [
"The planet is not homogeneous in terms of element distribution now even though we believe that it was, mostly, at the time of formation, so in a sense, a lot of elements are \"anomalously abundant\" in the earth crust. We even have a term for one class of scuh elements, the Large Ion Lithophile elements, which ba... | [
"Last I heard, phosphorus seems to be a lot more abundant on Earth (or in the solar system in general) than anywhere else we've looked. Since it's an element pretty essential to life, it may be one of the main reason we have life here but can't see it anywhere else.",
"Edit: Isaac Arthur to the rescue ",
"https... | [
"Uranium's an interesting one because pop culture tells us that it's only found as glowing green crystals in remote caves in the desert, when in actuality it's somewhere around forty times more abundant than Silver in Earth's crust; somewhere around the same order of magnitude as Tin and Tungsten. The exact figure ... |
[
"Do astronauts on extended missions ever develop illnesses/head colds while on the job?"
] | [
false
] | null | [
"Head colds actually significantly impacted Apollo 7, the first manned Apollo launch. All three astronauts developed head colds during the course of the 11-day mission. They became snappish and irritable, and refused a number of orders from the ground. The blame for this \"mutiny in space\" is mostly placed on m... | [
"Chris Hadfield's book ",
" talks about the medical isolation Astronauts undergo before heading to space.",
"This article",
" states that 10 days before launch, they're screened for illness and cleared for quarantine if good. Quarantine lasts a week to allow latent symptoms to surface. ",
"So it's still pos... | [
"Pathogens can't come from no where, so if no one going to space had any pathogens on them, and the equipment didn't either they could not become sick from infection, while in space.",
"That said this will never happen, because that level of sterilization would almost defiantly kill the astronauts, if we assume i... |
[
"What is exactly phantom limb pain?"
] | [
false
] | A little background : I'm an amputee for 11 years, and I can still sense my left leg like it was there. I want to know what causes that? Is my brain screwing with me? Is there any solution? Because sometimes, especially when there's too much humidity in the air, the pain becomes a bitch. I'm sorry if this isn't the rig... | [
"I am not going to pretend that I have any accolades that give me the authority to speak scientifically about this. However, there is a facinating Ted Talk about this that you may find informative, and not linking it here would be a travesty. If you skip forward to about nine minutes in, that's when he really hits ... | [
"Awesome! Will check the link at home, for some reason it doesn't load very well on my phone. Thanks, man."
] | [
"I think you can get your answer from the wiki page as far as what it is...I'll assume it covers the fact that we have created a \"map\" in our brain about where out body parts are, so just because our body doesn't have it anymore doesn't mean our brain understands it isn't there.",
"What I think is the more impo... |
[
"How does your body know when someone is behind you?"
] | [
false
] | People call it the "sixth sense" but how does it actually work? Why does your body get that tingling feeling when someone is behind you? My hypothesis is that the pressure in the room changes just enough for your ear to pick up on it. How does it really work? Edit: It's a hypothesis, not a theory | [
"In a quiet environment your sense of hearing is better than you think. If you stand near a wall, and lean in closer to it with your eyes closed, you can easily pick up audible, \"ambient\" sounds that will tell you fairly accurately how close you are to the wall. We're not bats, but we have a limited ability for p... | [
"We're not bats, but we have a limited ability for passive echo-location...",
"backing up this statement"
] | [
"It's pretty clear that he didn't think it was paranormal. "
] |
[
"I need help understanding infinity and 0"
] | [
false
] | [deleted] | [
"This is true for any two numbers. You can always describe an asymptotic curve that approaches a limiting value but never reaches it.",
"Infinity is a different concept altogether. There can't be any infinite integer because you can always still perform operations on it. If that number exists and is X, what is ... | [
"Here's some information on Limits",
". This might help to understand the concept of 0 and/or infinity."
] | [
"Thinking in terms of something like distance, I do not see how both 0 and infinity and exist at the same time.",
"It's important to note that ",
"infinity is not a real number",
" -- infinity only exists in nature as a ",
" (and really, it represents an absence of limit more than anything else). It is not... |
[
"What is your preferred method of plasmid mutagenesis?"
] | [
false
] | [deleted] | [
"What organism?",
"I've had some success with the Agilent/Stratagene Quickchange II kit, but I'm guessing you've tried that already. ",
"Where is the SNV located? Do you need to stitch two fragments together to make your construct? Ones in the middle become a pain and, in such cases, I've had luck with some P... | [
"Used to do PCR fragment assembly or quickchange.",
"Lately, switched to gBLOCKS from IDT and Gibson Assembly (NEB or make your own mix). Highly recommended."
] | [
"Not at all! Askscience has tons of high quality scientific questions, they're just not as nuanced and technical and thus do not warrant such esoteric vocabulary."
] |
[
"Is it possible to make eye-glasses that are hydrophobic?"
] | [
false
] | Inspired by walking with glasses in the rain, I was wondering if there is a way to make glasses that would allow rainwater to slide off (without the use of some spray). If not, why? Can hydrophobic glass, if that's a thing, be shaped into a lens while maintaining it's hydrophobic-nature? | [
"It is very possible to chemically treat glass to modify the surface chemistry and make it even more ",
" hydrophobic. An oxidized glass surface has many -OH groups exposed which can be bonded with other chemicals to create a hydrophobic surface. Note that this is a chemical bond, and is distinct from the additio... | [
"Is there some way to make lenses that are fingerprintphobic? Cause that's what I really need."
] | [
"Yes and no. Fingerprints are mainly just oil, and the governing physics are the same as for water. You can make an olephobic (oil repelling) surface a number of different ways, but I'm assuming you want to stick to your previous condition of a chemical surface treatment. The contact angle is a function of the diff... |
[
"Over the course of a half-life, what happens to the decomposed(/decomposing) part of the substance?"
] | [
false
] | For example, let's assume that the 2nd half life had just occured. So now 3/4 of the original substance is gone. What happened to that 3/4th portion? Where did it go? And how does it reform into something else? | [
"The substance is not \"gone\" so much as transformed. I presume your are primarily referring to radioactive decay; in radioactive decay its not that 1/2 the substance is gone, it just means you have 1/2 as many of that nuclei as you started with. There are many types of decay, but a common one is beta-minus wher... | [
"But what exactly happens with the decayed product? Does it just hover throughout the subatomic world without a bond for the rest of the universe (or at least when all bonds finally break)?"
] | [
"I'm not sure I understand your question. The decay products are still atoms, just like the parents and will behave however the new chemical element would behave. Lets continue with the carbon-14 example and assume a C-14 atom is part of a CO2 molecule. When the C-14 atom decays, it becomes a N-14 atom. So the ... |
[
"Why is Raman scattering such a low probability event?"
] | [
false
] | In the optics lab that I work as an undergraduate in, we have a Raman setup, and I was told by the graduate students that Raman scattering typically has a probability of occurring of something like one photon in millions or maybe even billions of photons. I understand the process of how Raman scattering works in terms ... | [
"The classical answer is that if you Taylor expand the polarizability of a molecule w.r.t. the nuclear coordinates, the lowest order term is the polarizability that controls the strength of Rayleigh scattering, while the next leading order term controls Raman scattering. This next leading order term is slope of pol... | [
"\"exciting the system to some virtual state, and then letting it relax pretty much instantaneously back to the original state.\"",
"\"the phonon event has to happen at pretty much the same time as the relaxation, which is improbable\"",
"Can you elaborate on how those are different? I'm having trouble understa... | [
"In both cases, you're exciting the system to an unstable energy state. When it Rayleigh scatters, it just returns to its original state. When it Raman scatters, the system needs to generate a phonon mode to absorb the correct energy from the photon. This generation is essentially governed by temperature (stochasti... |
[
"Why don't all colleges have a distributed computing platform?"
] | [
false
] | Why don't all colleges give their students an option to install a distributed computing client on their computer? It could be a requirement of using the campus network or be an opt-out program. Is it too hard to make such a client? Is there too little benefit to the professors who would have access to it? | [
"A large bureaucracy that doesn't understand computers, for one."
] | [
"My friend, I go to a small university. We have exactly 2 tech people, both of whom are ridiculously incompetent. We're lucky we can print over the network."
] | [
"not every problem is necessarily well solved by distributed computing. It's largely for taking giant data sets, breaking it up into chunks and having users analyze the data. Or a parameter space that can be used to generate data and then analyze that data.",
"Then you also have to rewrite your code to work with ... |
[
"Is crying a learned response? For example, if every time a small child fell, and you laughed instead of coddled them, would they laugh every time they got hurt?"
] | [
false
] | null | [
"The act of crying is not a learned behavior. How to deal with a situation is kind of, according to:\n",
"http://www.sciencedirect.com.proxy1.athensams.net/science/article/pii/016363839190052T",
" and ",
"http://onlinelibrary.wiley.com.proxy1.athensams.net/doi/10.1111/j.1467-7687.2004.00344.x/abstract;jsess... | [
"(Differences between personalities aside) - If you always panic and overreact when a child falls, they will indeed learn to react the same way to that situation and grab for attention. If you act calmly, they will learn to react the same. If you laugh, they will most likely laugh for the small bumps and falls (and... | [
"I wouldn't think it would extend that far. Some cultures smile when they are nervous/scared, but they aren't actually happy"
] |
[
"Dogs, cats, horses, cows and other animals that sometimes have white stripes down their face/nose: Is this an example of common ancestry or convergent evolution? What's the advantage here? Camouflage? Attraction? Seems like an oddly specific reoccurring mammal trait."
] | [
false
] | [deleted] | [
"The white strips you're talking about are just coloration patterns, and the animals you mentioned as examples are all domesticated, which would mean that it's not evolution at work here, rather artificial selection and I can't think of any wild animals with that specific marking. So there's no real selective advan... | [
"I think it's important to mention that evolution does not equal natural selection. Natural selection is an agent of evolution as it artificial selection. The only real difference between the two is that the selective pressure in artificial selection is being provided by humans. I think your last sentence is perfec... | [
"Thanks for answering. It didn't occur to me that the commonality is mankind. I forgot about guinea pigs, too. This brings up new thoughts... like how intentional this trait is (and if intentional, why?), or if that's just what will happen to mammals if you breed to get the tuxedo look, or if this a curious side-ef... |
[
"[physics] Becuase it's possible to \"mimic\" a 3-d image on a 2-d surface, would it be possible to make a 3-d object that \"mimics\" what a fourth dimensional object would look like?"
] | [
false
] | null | [
"http://en.wikipedia.org/wiki/Tesseract"
] | [
"http://en.wikipedia.org/wiki/Tesseract"
] | [
"I don't have the answer, but I just wanted to say this is a splendid question."
] |
[
"If you had enhanced strength by using a powered exoskeleton, could an average person fly by flapping man-made wings? How big would they have to be?"
] | [
false
] | , but let's say you make one around 40 pounds. Approximately how much weight/force would you be carrying/pushing with the necessary wing size? | [
"Well, the objective would be recreational enjoyment. We already have jetpacks, but some might want the fun of bird-like flight. ",
"Would the wings need to be around the size of the average hang glider? And can you move in multiple directions with a servomotor?"
] | [
"Well, the objective would be recreational enjoyment. We already have jetpacks, but some might want the fun of bird-like flight. ",
"Would the wings need to be around the size of the average hang glider? And can you move in multiple directions with a servomotor?"
] | [
"Couldn't you just make wings big enough to carry the weight?"
] |
[
"Does Plan B prevent implantation or not? If not, why isn’t there an emergency contraceptive that does?"
] | [
false
] | The FDA says that Plan B however almost says it simply delays ovulation. I have also heard from my own OBGYNs that Plan B only works before ovulation. If Plan B isn’t effective at preventing implantation, why isn’t there an alternative that is? Is it a physiological issue or is no one simply interested in developing a ... | [
"The closest alternative to anti-implantation is anti-fertilization, via copper IUD aka Paraguard.",
"Plan B is simply produces a transient surge of progesterone in your body in order to delay/prevent ovulation. If you take the pill AFTER you've ovulated, then there's nothing the pill can do. If you take Plan B s... | [
"Studies show for a fact that levonorgestrel will usually delay or prevent ovulation. Studies also show that the it ",
" interfere with fertilization and implantation in some cases. ",
"Unlike mifepristone (R-486) it does not cause the rejection of an implanted embryo.",
"The ",
" actions have not been exte... | [
"That's actually pretty cool. It's a lot easier for conservative jurisdictions to regulate Plan B or medication than to regulate metals like copper. I'm AMAB (she/her) and don't know much about IUDs but I'm curious how viable it would be to make a comparable spermicidal copper instrument at home from common copper ... |
[
"Why does cold temperatures dry clothes?"
] | [
false
] | In a rainy day, if I leave wet clothes in a bedroom with a heater, they will dry. And if I leave wet clothes in a bedroom with cold air conditioning it will dry. Why? | [
"Important part is the that liquid water will always just spontaneously evaporate with speed depending on a number of factors like: temperature, humidity of the air, and airflow over the surface.",
"An AC lowers the air temperature, slowing down evaporation, but also lowers humidity, speeding up evaporation. AC a... | [
"Once you get to freezing temperatures the water will solidify and no longer evaporate.",
"It can actually be surprisingly effective to dry clothes on a freezing but sunny day. Some of the water will freeze, but the ice will then sublimate away."
] | [
"Once you get to freezing temperatures the water will solidify and no longer evaporate.",
"You still have molecules entering the gas phase, the rate just keeps going down."
] |
[
"Is it possible to walk from the southest of South America to the southest of South Africa?"
] | [
false
] | null | [
"So in the 1980's especially it was possible to walk over an ice bridge in the Bering Strait, but for the last two years the ice there and elsewhere (e.g. between Russia and Canada via the north pole) has been more sparse, inconsistent, and shifting. It certainly used to be possible, but I'm not sure if it is this ... | [
"Earth Sciences"
] | [
"Earth Sciences"
] |
[
"What's actually going on inside your stomach when you feel \"butterflies\"?"
] | [
false
] | null | [
"This is a fairly common question on ",
"/r/askscience",
". Here's a list of previous threads on the subject:",
"Why do we sometimes feel emotion in our stomachs (e.g \"butterflies\" and \"that sinking feeling\")?",
"What's happening when one gets \"butterflies?\"",
"What causes the \"butterfly\" gut sens... | [
"The answer you're looking for is in one or more of those posts. I listed all of them to give you an idea of the regularity of this question."
] | [
"You're linking me to another post where you wrote that exact same thing but with no resolved answer. Looking at the post before you link me to it would be helpful. "
] |
[
"How does r/askscience regard scientists in the public eye and how science presents itself to the public? (ie Dawkins, deGrasse Tyson, Hawkings, Harris, etc.)"
] | [
false
] | There seems to be two ways the public scientist engages non-scinence communities or the general public. One, as passing along the findings of science such as Sagan's PBS series "Cosmos" or Hawking's "A Brief History..." Second, as an agent of social/cultural change such as science backed Atheism or Harris's newer book ... | [
"First of all, it's Hawking. No ",
".",
"Second of all - and I say this with all respect due Neil Tyson - I always shake my head when I see his name right next to Stephen Hawking's.",
"No scientist will look down upon science education and communication, as long as it's well done and doesn't communicate mistr... | [
"What adamsolomon said. However, I'd also like to add an important point.",
"We are embarassed when scientists start speaking about things way outside their field or without justification. This seems to happen not infrequently to famous particle theorists/astrophysicists in their old age. For example, recent \... | [
"Tyson is one of the most important figures in science today. Why? Because he's a great educator, and makes the average person understand the value of science. Most scientists do a pretty piss-poor job of outreach,and I'd argue that that's okay, as long as people like Tyson are picking up the slack. If our culture ... |
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