title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"How do atoms convert to energy?"
] | [
false
] | If matter and energy and interchangeable, how do atoms convert to photons? | [
"Take the simplest atom - a hydrogen atom, which is composed of one proton and one electron bound together. There is a certain amount of energy that you would need to 'pry' these two particles apart, i.e. to drag the electron away from the proton, which results from the fact that they have opposite charges and so t... | [
"If matter and energy and interchangeable, how do atoms convert to photons? ",
"you are equation energy to photons and matter to atoms which isn't very correct. ",
"E = mc² means that mass is one form of energy. in a reaction in principle if the energies involved are high enough, the mass can change into a dif... | [
"Thanks for the reply!"
] |
[
"Why do bruises adopt different colors, such as red, yellow, green and black?"
] | [
false
] | null | [
"Bruises are collections of blood in the tissue. They start out red/purple because that is the color of ",
"hemoglobin",
", a major component of the red blood cells that are leaking out of ruptured vessels. These red bloods cells get stuck in the tissue are are slowly degraded. The first substance that hemoglob... | [
"Bonus bonus: in ",
" (the book), Lecter amuses himself by telling the FBI that the killer's name is William Rubin, which it wasn't. Bilirubin is part of what gives poop its color so the clue was bullshit."
] | [
"\n",
"\n",
"\n",
"\n",
"\n"
] |
[
"Is there a correlation between skin cancer in people's arms and on which side of the road they drive?"
] | [
false
] | For example, is there a higher rate of skin cancer in the left arm of right-side drivers? Conversely, is there a higher rate of skin cancer in the right arm of left-side drivers? I think about this after taking long trips in the car. My left arm is always slightly darker than my right. There is a man at my church who had melanoma in his left arm after driving a Lance delivery truck for 35 years, but his right arm was fine. | [
"Ooh! Oooh! I'm a random idiot undergrad with no qualifications whatsoever but I know something tangentially related to this! Specifically, ",
"here is a case study",
" of a truck driver with unilateral skin damage due to sun exposure through his window.",
"According to the study,",
"Ultraviolet A (UVA) ra... | [
"Truck drivers get some serious damage from the sun.",
"Here is a picture of an old retired truck driver ",
"http://i.huffpost.com/gen/634768/thumbs/o-BILL-MCELLIGOTT-SUN-DAMAGE-570.jpg?4"
] | [
"That study is one of the few/only studies done on the 'unilateral' side of things, specifically caused by something like truck driving. A wide-spread epidemiological study of this could be interesting, comparing say, Australia, where we sit on the right side of our cars, with the US, where you sit on the left, and... |
[
"Is there a meaningful variance in the maximum/minimum wavelength the human eye registers?"
] | [
false
] | To put it in another way, are there people who can see a bit into the part of the spectrum what the general population would regard as infrared or ultraviolet, or can't see certain pure reds or purples at the ends of the visible spectrum? | [
"There are individual differences that are measurable and significant. Depending on what population you study (normals, deutoronopes, or protonopes), which cone type you are looking at, and depending on what methods you use, you get slightly different results. Overall, the standard deviation of shift in spectral se... | [
"I was watching a show the other day that noted a man who had cataracts, and had gotten surgery to repair the problem. After the process he was able to see uv wavelengths. ",
"An article about him and seeing uv: ",
"http://www.extremetech.com/computing/118557-the-eyes-have-it-seeing-ultraviolet-exploring-color"... | [
"Follow up question for someone in the field:\nWhich retinal cells transduce this information?"
] |
[
"Multiple basic questions about the Hubble photos"
] | [
false
] | The most pressing one: are these all (except when explicitly stated otherwise, e.g. "Saturn in Infrared") a representation of what a normal human eye would see if they were standing right next to the end of the telescope? Are the colors really like that? On to the more basic ones: | [
"1) It's made up of basically the same stuff as everything else - 3/4 hydrogen and 1/4 helium, then a small amount of heavier elements. The Pillars of Creation are made of dense (\"molecular\") gas that's getting blown away by some bright young star cluster. The gas isn't uniform, so there are some dense knots that... | [
"Thank you very much!"
] | [
"Thank you very much!"
] |
[
"Why does a laser spot look grainy?"
] | [
false
] | null | [
"To understand this, you have to first understand that light is a wave, and like other waves, sometimes the wave pulls up, and other times it pulls down. The brightness at a given point doesn't matter whether the wave is pulling up or down, just on how hard it's pulling. ",
"A laser produces coherent light, so wh... | [
"They're called ",
"speckle patterns",
", and it's due to interference."
] | [
"No. This is an artifact of rapidly turning on and off the LEDs for each digit & segment in sequence to allow fewer pins to control more LED's. Likewise, if you wave your hand in your field of view quickly at night under non-incandescent illumination (particularly sodium vapor) you will see it appear to fade in and... |
[
"Why is the softness of ice cream sometimes different?"
] | [
false
] | Why is it that sometimes when I take ice cream out of the freezer, it is extremely hard, while other times it is relatively soft? When hard, even a spoon soaked in hot water doesn't scoop it well. When soft, a normal spoon with minimal effort works perfectly fine. The temperature of the freezer isn't changed and I keep the ice cream in the same place. Is there a way to prevent this minor inconvenience? | [
"Just because your freezer is set to the same temperature, doesn't mean that it is the same temperature all the time.",
"Every time you open the door, the cold air falls out and is replaced with warmer room air. The freezer needs to turn on to cool it back down to the desired temperature. In doing so, it will act... | [
"The softness of ice cream depends largely of the particle size of the frozen water crystals, which in turn depends on how the ice is mixed and frozen. The air content also have a say, as mpranav explained, but you have very little control over that unless you make your own ice cream.",
"Smaller crystals lead to ... | [
"The softness of ice cream depends mostly on the air content in the ice cream as well. Soft serve ice cream, for example, is very easy to dig into because of the microscopic air bubbles included in freezing. When you put ice cream in your freezer, its just the slight variations in air content that tell how it will ... |
[
"Did a Lockheed SR-71 “Blackbird” fly above a Space Shuttle orbiter?"
] | [
false
] | null | [
"That not possible, the max altitude the SR-71 could achieve was well below any orbit the Shuttle was flying at.",
"There was several inspection methods for the heatshield. Some included taking pictures from ISS, some involved a camera mounted on the robotic arm."
] | [
"Thank you so much for the reply! That is what I thought. I wonder where the rumor started. Is it theoretically possibly for an SR-71 to zoom climb or pull up to reach space? I do not think so, but I would love to know a professional’s thoughts on this."
] | [
"One other fun note. According to Wikipedia, “On 28 July 1976, SR-71 serial number 61-7962, piloted by then Captain Robert Helt, broke the world record: an \"absolute altitude record\" of 85,069 feet (25,929 m). Several aircraft have exceeded this altitude in zoom climbs, but not in sustained flight.”\nI wonder wha... |
[
"Why when you are cooking and you lower or turn off the heat does the pot steam noticeably more?"
] | [
false
] | Why when you are cooking and you lower or turn off the heat does the pot steam noticeably more? | [
"I've never noticed than, I'll try it out next time I boil something!",
"The reason though, I believe, is the decrease in temperature. Water vapour is colourless and invisible to the human eye. What you call ",
" is the water condensing into tiny micro-droplets as the vapour cools down.",
"With the heat on yo... | [
"Are you using a gas stove? Sometimes when adjusting the valves on a gas stove (that is, turning the knobs to change the amount of gas burning below your pot) you pass through positions you don't expect. If you are talking about a gas stove, then when you pass from the \"low\" position to the \"off\" position, you ... | [
"I have noticed it on both gass stoves as well as electric and also even on campfires when i pull a pot off of it completely. It spears to definitely be from a reduction of heat, not an increase or burst of heat. "
] |
[
"What happens when microwaving a lit match?"
] | [
false
] | When you microwave a lit match which is contained inside a glass cup you can create plasma as seen in this video: When I attempted this I got a similar result and the glass eventually shattered, so my question is what causes the plasma and the shattering of the glass? | [
"Fire produces ions and free electrons as chemical intermediaries. Plasma is conductive, microwave induces currents in plasma, creates more plasma. Now you have a cup of plasma. Fairly clever really.",
"Heat makes objects expand. In the case of rigid, brittle objects like glass, uneven heating often causes enormo... | [
"Ionizing radiation(X-ray, Gamma rays) can ionize the air, because the frequency is high, it can hit atoms and take out small particles.",
"The lower-frequency radiation can ionize air too, but this is because of heating effects(If I'm not mistaken).",
"Why doesn't a microwave cause a plasma by itself? The ener... | [
"Not sure if the new pyrex (tempered glass) can handle that. I'm sure the old pyrex(borosilicate glass can), though."
] |
[
"Engineers and Scientists of Reddit, what are the difficulties from having a person skydive from the ISS? What kind of suit would be required?"
] | [
false
] | Is it realistic to beat the record the Felix Baumgartner made with his jump in the next couple of years? | [
"if you jump off the ISS you are in orbit.. for a very very long time.. you don't fall from things in orbit, you find yourself in your own orbit. ",
"if you were to jump from a stationary hovering platform in space and were to fall you would incinerate in the atmosphere. "
] | [
"you burn up in the atmosphere like any other piece of debris that falls to earth. ",
"you would need to be in some sort of capsule or a suit that was extremely rigid and protected from heat.. falling to earth at 17,000 MPH is dangerous shit. "
] | [
"all the thermal insulators i have ever heard of (the kind which can withstand reentry heat) are ceramic based. Those tend to be brittle. ",
"Hopefully someone else chimes in on this post and can give you a better materials answer. "
] |
[
"What is the difference between quantum uncertainty and ordinary uncertainty?"
] | [
false
] | In an electron diffraction experiment, we can shoot electrons one at a time through a grating, and they will make a diffraction pattern, showing that the electrons are really waves. This diffraction pattern is a statistical distribution of the electron wavefront at the detector, and the grating helps to illustrate the connection between uncertainty in position and momentum. If i make macroscale experiments, i will also get statistically distributed results. If i make different experiments on the same sample, the order of experiments is usually important. With better methods i can reduce the interaction between the experiments. Is the Heisenberg uncertainty just the theoretical lower bound on this interaction, or are there other differences as well? | [
"The short answer is that the difference is one between true, intrinsic uncertainty in the quantum case, and a simple lack of information in the classical case. A concise way of stating the distinction is to say that it is one of \"quantum uncertainty\" vs. \"classical ignorance.\"",
"To look at this idea more cl... | [
"It's the difference between \"we don't know because we haven't checked yet\" and \"we don't know because it hasn't actually been decided yet\". In QM, the universe genuinely ",
" where the electron is until it matters to something outside of the isolated quantum state because the electron would interact with it.... | [
"In the classical case, the uncertainty is just due to you not knowing what the exact position and velocity of each particle is, but we can still talk about each particle having a hidden value for both momentum and position. In quantum mechanics, these hidden variables can't exist locally. Here is what I mean:",
... |
[
"On aircraft that crash in water why are their black boxes kept in water after found?"
] | [
false
] | Yo know, the typical cooler filled with water to transport the black box for further analysis | [
"If you take the electronics out of salt water, exposing them to air can cause corrosion and potentially damage data. They leave them in the salt water and only take them out when they're in a position to clean everything properly. It can take 3 days to clean and then dry the electronics so data can be extracted."
... | [
"The earlier models of flight recorders were based on \"wire loops\". In the early days of sound recording thin wire was used as a recording medium, as the plastic tape/iron oxide tapes we are/were familiar with had not been perfected yet. When it was decided to make flight recorders standard equipment one of the ... | [
"The newer units store data on solid state drives, the older ones and they're still in use store data scored onto strips of metal. The metal strips would be the ones liable to corrode in ways to make it difficult to read. The solid state ones could well be done that way, not sure that it'd be freely available at so... |
[
"If heat rises, why are the mountains frozen?"
] | [
false
] | null | [
"The temperature rises in the stratosphere because that is where much of the UV energy from the sun is absorbed."
] | [
"The temperature rises in the stratosphere because that is where much of the UV energy from the sun is absorbed."
] | [
"That doesn't have anything to do with why mountains are cold though. Mt. Everest is firmly in the troposphere, though may sometimes be in the tropopause (the gray area between the troposphere and the stratosphere).",
"EDIT: And then I read Jeffy_Weffy's last sentence. I'm not changing it though, I was wrong to a... |
[
"If your bladder is full do you dehydrate slower?"
] | [
false
] | Is there a mechanism that senses the bladder is full and stops/slows pulling water from your body? Or is water just pulled from your body automatically without regard to your bladder? | [
"This is a fairly basic and simplistic overview of kidney physiology, but essentially there are three things that govern how much fluid they excrete.",
"First is the pressure gradient driving the filtration of blood at the beginning of the kidney (glomerular capsule).",
"Second is the excretion/reabsorption of ... | [
"There are several mechanisms by which kidney function can be controlled. Unfortunately, the bladder is not involved in any of those (as far as we know today). Evolution would not favor such a mechanism. In nature, we dont really have to hold our pee for hours. Also interesting: even if you dont drink anything your... | [
"Technically yes, as you can just drink the urine to rehydrate yourself briefly."
] |
[
"How Many People Can the Earth Hold?"
] | [
false
] | null | [
"correction:",
"surface of a sphere: 4",
"r",
"0.5 * 0.25 = 0.125 m",
" area per person.",
"((4 * 3.14 * (12 756 200",
" )) * 0.2889) / 0.125 = 4.72356404 × 10",
" people"
] | [
"You've corrected some of his errors - namely the \"footprint\" calculation and lack of conversion from square kilometers to square meters when dividing the areas - but you seem to have introduced your own.",
"You've correctly stated that the surface area of a sphere is 4 pi r",
" - however, note that he was us... | [
"I suppose I meant sustain, I don't really see the benefits in putting 118,148,997,600 shoulder to shoulder. I do however, find it interesting that about 6% of this shoulder space is already occupied. "
] |
[
"Are two lottery tickets always the optimal number of tickets to buy?"
] | [
false
] | null | [
"All that matters is \"X\". If it is less than 100 then the maximum expected value is always at 0 tickets. If X>100 (can happen in charity raffles if the prizes are donated and worth more than the total price of all the tickets) then more tickets is always better. If X=100 the EV doesn't change between any number o... | [
"Lotteries are always designed so they pay out less than the total put in. The optimal amount is always 0."
] | [
"I don't really play the lottery, and I don't have delusions of winning and I get how hard it is to win. Just wanted to see how the math works for this as a thought experiment. "
] |
[
"Why do shower curtains attack?"
] | [
false
] | Every morning my wife and I take a shower together. When one of us leaves the shower, the shower curtain starts to aggressively encroach on the personal space of the person still in the shower. Why does this happen? | [
"There's a wiki",
". Surprised? I was."
] | [
"Until I looked at the URL I thought you meant an actual whole wiki about this one effect, and was ",
" surprised..."
] | [
"I'm going to take a stab and say that the egress of one person starts a circulation airflow and the warm shower air is flowing upward and drawing cool air from the rest of the bathroom in under the shower curtain."
] |
[
"Has there been any research on mathematical thought and the brain?"
] | [
false
] | null | [
"Yes. There have been many studies. You can get a sampling just by searching for something as simple as \"math fMRI\" in google scholar. Do you have a more specific question?"
] | [
"In general, most of your brain is active no matter what task you're doing: solving a math problem, for example, involves seeing the problem, reading, understanding, doing math, making decisions, accessing memories etc. ",
"At best, we can ask \"are there regions of the brain that are necessary for solving math p... | [
"Are there any areas of the brain that are known to show activity when one answers an equation? If so what are they and how do they work?\nIs there a basic structure behind such a process?"
] |
[
"Top down versus bottom up models of ecology: Why not syncretic/hybrid views of ecology?"
] | [
false
] | In my undergrad ecology courses, my professors explained how ecologists view ecosystems either using top-down models (apex predators influencing the ecosystem the most) versus bottom-up (detritis feeders and producers influencing the ecosystem the most). I was taught that most ecologists subscribe to either view of ecosystems. What I never understood is why having that model is even useful or important, because it seemed to me that both sides had valid ways of understanding ecology, but also didn't understand why going one way or the other would be more useful way of understanding the environment. It seemed to me from reading the debate about top down versus bottom up that it would make just as much sense to view different dynamics in different ecosystems and throw out both models and just try to understand ecosystems as they are as they come. I would like to hear opinions and thoughts about top down versus bottom up and would love to be pointed out to supplemental readings as well. | [
"Are you familiar with Robert Ulanowicz's work? He is a strong proponent that ecosystem organization results from both bottom up (i.e., traditional reductionalist) and top-down influences. (Disclaimer: I'm not an ecologist, but I've been reading Ulanowicz's papers on information theory.)"
] | [
"Can you link one of his papers?"
] | [
"Here's",
" an overview I like. His stuff can be a tough read depending on your background. I found his book ",
" to be a gentler, albeit much longer, introduction."
] |
[
"How to solve this Combination problem?"
] | [
false
] | null | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"/r/AskScience",
"/r/HomeworkHelp",
"guidelines.",
"If you disagree with this decision, please send a message to the moderators."
] | [
"But it's not for my homework, my dad was asked this question by his friend, and my dad couldn't think of the answer so he asked me.",
"And neither could I think of anything so decided to ask reddit. ",
"/r/askscience",
" is the largest sub for these kind of question/doubt so I decided to ask there. If it doe... | [
"/r/LearnMath",
", ",
"/r/AskMath",
", ",
"/r/cheatatmathhomework",
", ",
"/r/HomeworkHelp",
". The kind of math is \"combinatorics\"."
] |
[
"With normal usage, are teflon pans actually bad for you?"
] | [
false
] | If one avoids scratching teflon (or other non-stick) pans, are there any negative health effects to worry about, short or long-term? I can't seem to get a good science-based answer (probably partially because I can't access the actual papers, and don't have the expertise to interpret them properly). | [
"Your definition of \"normal usage\" may differ from other people's, so I can't say exactly whether it's safe in the manner that you're using it. However, here's a ",
"pretty easy to read summary of several studies",
".",
"Summary of the papers:",
"In peer-reviewed research, the lowest temperature known to... | [
"The \"scratching the pan\" thing is a red herring. The important thing is how much perfluoro material, perfluorocarboxylic and sulfonic acids, are released. ",
"Studies at NOAA where I work have shown increasing levels of these contaminants in water and marine organisms. They are known endocrine disruptors. Also... | [
"If you have birds, the best thing to do is to simply give or throw away your teflon.",
"Is a single meal, or a single pan, worth the life of a companion?",
"We switched to cast iron after getting our birds and learning about teflon.",
"Turns out, they're way better anyway... :D"
] |
[
"Do men and women utilise peripheral vision in different ways?"
] | [
false
] | I can't remember now what it was, but something today made me wonder about this. We all have a certain degree of it, and surely we're all attuned to respond to different things in different ways, but has research been done into how people make use of it? Humans having been hunter gatherers for a long time, with gender-based division of labour... Women staying back in the family group lookin after the young while men go off to hunt... Could it be that women notice faces more easily in their peripheral vision, while men notice shapes and cues better... I'm not trying to convey a sexist agenda here, I'm just curious if there's been any research about this. I know there are hardwired differences between the genders such as how women see more colours than men, amongst other things like this. | [
"Women staying back in the family group lookin after the young while men go off to hunt",
"On the contraire! Women in simplified hunter-gatherer societies, due to the society having a low division of labor, are very busy. The society as a large ",
" hunters/gatherers, and everybody pulls their weight regardless... | [
"Males and females use their brain differently because there is a difference in brain connectivity. When they are both performing the same task, different areas in the brain are activated.",
"The typical male brain has connections that mostly run back and forth of the same brain hemisphere, which can account for ... | [
"I've read that in Hunter/Gatherer society, men would go out on the day(s) long hunts while women reared the children and foraged close to the tribe's camp among many other likely duties. ",
"For this, men required better focal distance and hand/eye coordination and relied on the 'pack' to provide security in the... |
[
"If microwaves have a longer wavelength than visible light why can they harmful?"
] | [
false
] | null | [
"They’re harmful at high intensities. And that’s not due to ionization, just just burning."
] | [
"Then why is visible light harmless to our skin"
] | [
"It’s not harmless at high enough intensities to cause burns."
] |
[
"Plenty of animals produce highly acidid fluids (e.g. stomach acid). Do any animals produce highly basic fluids?"
] | [
false
] | null | [
"I know that unlike mammals, the gut of many (if not all?) insects is very basic (around pH 10). I believe this is the primary reason why BT toxin (a common pesticide) kills insects, but doesn't hurt mammals."
] | [
"The human duodenum produces a fairly alkaline solution to combat the acidic nutrients leaking out of the stomach into the intestine. Human males produce a slightly alkaline solution to add to semen in order to counteract the acidic environment of the female vagina.",
"A lot of insects have alkaline guts.",
"I'... | [
"Oh, neat. Searching for insect gut pH is returning some nice results. ",
"Physicochemical Conditions and Microbial Activities in the Highly Alkaline Gut of the Humus-Feeding Larva of Pachnoda ephippiata",
" ",
"pH profiles of the extremely alkaline hindguts of soil-feeding termites (Isoptera: Termitidae) d... |
[
"Why are fingerprints an individually unique feature of the human race? Are there other species that exhibit features like this?"
] | [
false
] | null | [
"Cow's noses have a unique pattern, and the nose-prints can be used for identification, similarily to our fingerprints ",
"link"
] | [
"Koalas are generally law abiding. Drop bears on the other hand are notorious for pinning their crimes on humans."
] | [
"Gorillas and chimps also have them. Koalas have fingerprints that are almost indistinguishable from humans.",
"www.odec.ca/projects/2004/fren4j0/public.../animal_fingerprints.htm",
"EDIT- ",
"http://www.odec.ca/projects/2004/fren4j0/public_html/animal_fingerprints.htm",
"Thanks sharoz"
] |
[
"Every computer program is compiled (or interpreted) by another program, called the compiler or interpreter. This includes compilers themselves. Is there a \"common ancestor\" compiler of all high-level programs today, and if so what is it?"
] | [
false
] | I assume the first compilers were written by hand in machine code. Then subsequent compilers can be written in the language implemented by that first compiler, etc. Is there a single hand-written program that basically "birthed" all high-level code we use today? | [
"No, not really. The methodology of programming is similar, but there is no single ancestor. You need to understand how the CPU works at the very low level. It fetches data from a memory location. That data contains a bunch of bits that represent an instruction. That instruction can be an add, multiply, jump t... | [
"There's still ",
" ancestry. It's mostly a sea of unrelated points, with no lineage, but there is ",
". At the risk of trusting StackOverflow, the original C compiler was based on, and written in B. The first B compiler was written in TMG, and the TMG compiler was written in assembly. So there's actually some ... | [
"Note that people have written C compilers in Assembly as well. While you can trace ancestry of the ",
" compilers, those weren't necessarily the most influential. The first ",
" C compiler was written in... surprisingly... C.",
"The first B compiler was written in TMG, but B itself was a simplified version o... |
[
"In the northern hemisphere, why does the sky lighten in the north early in the morning?"
] | [
false
] | I live at 47 degrees north. The northern sky lightens significantly earlier in the morning and stays light significantly later in the evening. Why is this? It seems at odds with the fact that the sun appears in the southern part of the sky. Shouldn't the southern part of the sky get light earlier, since that's where the sun actually shows up? | [
"The further north you go, the more the Sun appears to circle around the sky rather than go up and back down. You're far enough north that as it goes around, it's not too far below the northern horizon, so you see it's light there. But by the time it rises it's gone around more to the east. If you go far enough nor... | [
"Great! I felt like I needed to visualize something like that image, but I wasn't quite able to wrap my head around it. And I didn't have a globe handy. Thanks!"
] | [
"If you watch closely around the summer solstice, you'll see the sun rise around 55 degrees east of north. So it actually does rise in the northern half of the sky. Scattering in the atmosphere causes even parts of the sky far from the sun to light up."
] |
[
"Why does buoyancy depend on the weight of the displaced fluid?"
] | [
false
] | null | [
"Well nature is not obligated to be “obvious” to us. But when you wrote down an expression for the pressure gradient force on the submerged object, you find that it just equals the weight of the displaced fluid."
] | [
"Alright, I thought that maybe someone else in the last hundreds of years would have pondered over that question and found an answer. It is such a striking \"coincidence\" that those forces are equal."
] | [
"and found an answer",
"We have found an answer. But answers in physics come from math, rather than what \"seems right\"."
] |
[
"which would get warmer?"
] | [
false
] | If you had a sealed clear plastic container with air in it, and a sealed clear plastic container with co2 in it, and you left them both in the sun... would the container with co2 get warmer faster? edit// +faster | [
"hang on, something's backwards.",
"Heat capacity is a property that determines how much energy it takes to heat an amount of the material. Low heat capacity means it takes very little energy - high heat capacity means it takes more energy.",
"CO2 has other properties that sets it apart, of course, but there's ... | [
"Yes you are quite right, I have it backwards. CO2 would heat slower"
] | [
"The key is that the container containing carbon dioxide would cool more slowly, this is the problem with global warming. There is a very simple practical you can do to see this; all you need is plastic milk bottles, alkaseltser, data-loggers and a lamp."
] |
[
"Is there some sort of \"flower controversy?\""
] | [
false
] | I recently was talking to a friend who made a comment along the lines of "we don't understand how the first flowers developed, they came out of nowhere." Is this true? I have a hard time believing this one. edit: mystery, not controversy. | [
"I apologize\n",
"http://www.nytimes.com/2009/09/08/science/08flower.html?pagewanted=all"
] | [
"I apologize\n",
"http://www.nytimes.com/2009/09/08/science/08flower.html?pagewanted=all"
] | [
"ha, I was staring at a map of wales wondering what I was supposed to think."
] |
[
"How does one \"acquire\" taste?"
] | [
false
] | Does eating or drinking something enough actually alter your taste buds in some way? | [
"Things many claim are acquired tastes tend to have a bitter component (e.g. coffee, beer). Our tongue has only one receptor (actually a dimer thereof) for all \"tastes\" - sweet, salty, sour, umami - except bitter, for which we have somewhere in the 50's i think (correct me if i'm wrong). This is because we've evo... | [
"With taste it's the same as with other senses -- most of it happens in the brain, not in the sensory organs (the taste buds in this case). Think of optical illusion, as a comparison. ",
"How something tastes to you depends on:",
"So most of the factors that influence subjectively perceived taste have really no... | [
"Thanks! I'm learning all sorts of stuff today."
] |
[
"If an asteroid hit our moon, with the impact being large enough to be visible by the naked eye, what effect would it have on our planet? [xpost from /r/Askreddit. I didn't know /r/askscience existed]"
] | [
false
] | I'm not talking about the moon being obliterated, as that would obviously have an enormous effect. I'm thinking more of the smallest possible impact that could clearly be viewed by the naked eye. I started thinking about this when I was walking home in the early hours of this morning and (as always) was completely mesmerised by its beauty. | [
"I find this mildly hilarious. Think of all the shit we'd have to adjust"
] | [
"I doubt it would have any effect. If the moon became heavier or lighter then the tides would change in amplitude, and if its orbit changed then the length of the month would change, but I don't think an impact that size would be big enough to do either of those things."
] | [
"The moon moves about a kilometer per second. The biggest asteroid is about 1% the mass of the moon. If it slammed into the moon at opposite speed, and momentum was conserved, it would slow down the moon by about 3% and a lunar month would be about 31 days."
] |
[
"Does Acupuncture work?"
] | [
false
] | Basically what the title says: Does acupuncture work in the treatment of any medical condition (as more than a placebo)? I'm not thinking about undergoing it or anything, just curious. Note: It's not likely I'll value your input if you believe in homeopathy. | [
"There is no evidence",
" supporting acupuncture. It doesn't work and any reason people think it may work is the placebo. There is a small chance that any sort of pressure can help with back pain so it may slightly alleviate that but so would a massage for less hassle. ",
"It definitely doesn't cure or did any ... | [
"I'm an M.D., but I apologize in advance, because this will be somewhat anecdotal. (I will preface this by saying I've never had acupuncture performed on me and I certainly don't have any financial interest in referring people to an acupuncturist.) ",
"Of all the \"alternative\" medicines, this is the modality I'... | [
"Thanks for all your responses guys - the general consensus I'm getting is that it doesn't really work as an effective medical treatment and any affect it does have is negligible to the point of uselessness and can mostly be explained by placebo."
] |
[
"Why are we colder when wet?"
] | [
false
] | null | [
"Our sensation of being cold (or hot) is strongly affected by the rate at which we exchange heat with the environment. When we're wet, the water is almost always colder than the 37 C of our body. That means that heat flows from our body into the water on our skin. And since water has a considerably higher heat cond... | [
"this reminds of an experiment we did in middle school. you touch a metal table and it feels cool to the touch. you touch a wooden chair and not so much. but when you touch a thermometer to them both, they are the same temperature. the metal, being a better heat conductor, causes your skin to lose heat faster, so i... | [
"this reminds of an experiment we did in middle school. you touch a metal table and it feels cool to the touch. you touch a wooden chair and not so much. but when you touch a thermometer to them both, they are the same temperature. the metal, being a better heat conductor, causes your skin to lose heat faster, so i... |
[
"Photoelectric effect and electrons explanation?"
] | [
false
] | From what I understand, solar panels are made of materials that can be used with the photoelectric effect. Light reaches the object, and eventually the atoms receive so much energy that electrons break-off the atom and start moving freely. An example of these materials is silicon, a semiconductor. My question is, don't the silicon atoms eventually "ran out" of electrons to release, or where do they get new electrons from? I feel like I am lacking knowledge about this area nd would like someone to explain this to me, if the silicon atoms are constantly losing electrons which we are using for our electricity, wouldn't the silicon eventually "wear out"? Lose all its electrons? | [
"So silicon doesn't have free electrons. You dope it with something like phosphorus called N-type doping to add electrons and boron that adds an electron-hole in the silicon lattice called P-type doping.",
"If you stick these different types of doped silicon back to back, then you have a diode. Which is basically... | [
"From what I understand, solar panels are made of materials that can be used with the photoelectric effect.",
"Actually, the mechanism underlying solar panel operation is called the ",
"photo",
" effect",
", not the photoelectric effect. The photo",
" effect is when electrons are ejected from a material ... | [
"u/ZeroBullshitMan",
" covered it pretty well. If you have an electrically-isolated solar cell then the excited electrons will just move toward one side of your solar cell and sit there. But if you're connected to a circuit then you've got, say, metal wires that have electrons and other things in the circuit. Wha... |
[
"Is soap required to \"foam\" in order to work properly?"
] | [
false
] | null | [
"Nope! Two soaps that don't foam are laundry detergent and the type of soap that goes in dishwashers. If you put a foaming type of soap in either of those machines, it will cause a huge mess. However, those soaps still clean dishes and clothes just fine.",
"Lots of cosmetics companies actually add things (like so... | [
"No...that sounds like the definition of an old wives tale.",
"More foam nearly always means more foaming agents, nothing more. Some soaps foam more or less than others at baseline depending on the oil they were created from (coconut soaps foam more than castor soaps), but almost all of the foam you see in moder... | [
"Foam is not needed for soap to work. In fact, the less foam you have, the more soap is activly at work in the water. \nFoam is a by-product of soap, created by the fact that soap lowers the surface tension of water, allowing it to form bubbles. So lots of foam on the water means less active soap in the water. "
] |
[
"Why doesn’t our moon rotate, and what would happen if it started rotating suddenly?"
] | [
false
] | null | [
"It does rotate, but the time it takes to rotate around its axis is exactly equal to the time it takes to orbit the Earth. And as a consequence, we always see the same side of the Moon.",
"Now you might say: \"That seems a bit too neat to be a coincidence!\"",
"And you would be right, because it's not a coincid... | [
"The force of gravity falls of with the square of the distance. Despite this, the Sun is so massive that even though it's much further away than the Moon, it is still the gravitationally dominant body for our planet.",
"However, while the tidal force on our planet is a consequence of gravity, it is a function of ... | [
"Silly question but why doesn't the earth sync in the same way? A planet much closer to the sun would sync?"
] |
[
"Could a neutrino interact with a water molecule in my eye and release a photon that I could \"see\"?"
] | [
false
] | null | [
"Yes, there is an incredibly small probability of a neutrino interacting with something in your eye and you seeing it. It would most likely be a neutrino-electron elastic scattering, which can accelerate the electron to a velocity faster than the speed of light in that medium resulting in ",
"Cherenkov radiation"... | [
"I thought this was a super cool question so instead of working on calibration for my experiment I wanted to do a quick back of the envelope calculation.",
"so the cross section for inelastic scattering on a neutrino... okay thats way to complicated :P lets look at a well know neutrino experiment Super-K and comp... | [
"Roger that ",
"/u/EventHorizon511",
" Thanks so much. I always thought that it might be possible in theory!"
] |
[
"Physical significance of S(q) structure factor against scattering vector q?"
] | [
false
] | In diffraction experiments it is common to graph the structure factor against the scattering vector q. My question is what exactly do the peaks in the resultant plot from x-ray diffraction of neutron diffraction physically correspond to? Also, I think it would help to frame the answer in the case of a non periodic structure (or perfect crystal scenarios). Any help would be appreciated. | [
"Scattering is essentially a momentum transfer. The scattering vector is essentially just the difference in momentum of in the incoming beam with the detected beam. So that for diffraction you can have detectors either moving through different angles or set up at multiple angles, and at that specific angle if a ... | [
"So that basically means peaks in the structure factor have no direct physical significance other than the fact that they can be transformed back into position space and given known phases can calculate the RDF? Meaning that peaks are just |intensity|",
" maximums corresponding to little resultant impact that the... | [
"Its not as though momentum isn't physically significant. Diffraction techniques are generally use crystallographically so the position-space is what you're looking to get information on from momentum-space. The structure factor is however a direct reflection of the likelihood of transition between momentum state... |
[
"How Does Cherenkov Radiation work?"
] | [
false
] | How does Cherenkov Radiation work? Are you getting Energy from nothing, or is the particle slowing down? | [
"The particles are slowing down. It requires particles going faster than the speed of light in the medium (this is still slower than speed of light in vacuum). When the particles are slowed down to the speed of light in the medium the Cherenkov Radiation stops."
] | [
"To add to this, Cherenkov radiation is the electromagnetic equivalent of a sonic boom."
] | [
"Cherenkov radiation occurs when a charge particle goes though a medium at a speed superior of the speed of light in that medium.",
"Passing by, the charge particle interact with the atoms of the medium by changing their polarisation (imagine the atoms like little magnet, the charge particle make the magnet move)... |
[
"Can you get \"hit\" by the Earth?"
] | [
false
] | [deleted] | [
"Yes this is perfectly possible. The earth spins at a rate of 1 revolution per 24 hours on its axis (solar day) and revolves around the sun on an elliptical orbit at a rate of 1 revolution per 365 days(sidereal year). The earth travels at a speed of 108000 km/hr and the total distance covered over the period of th... | [
"Complete stop relative to...?",
"If you mean relative to say, The Sun, then yes, you would see The Earth hurtling towards you and smacking right into you with tremendous force."
] | [
"Yes, but note that there is not really such a thing as a \"complete stop\". You are always moving relative to someone. Staying stationary with respect to the Sun and \"waiting for\" the Earth to hit you at 30 km/s is exactly the same as considering the Earth to be stationary and you're crashing towards it at 30 km... |
[
"What is the origin of human sexual fetishes? Why can some be so particular and even self-harming?"
] | [
false
] | I can understand why humans would find things sexually attractive from an evolutionary standpoint, but some fetishes do seem out there and confusing. Some even self-harming. Like, cannibalism, BDSM, scat, castration, etc. What led the human species to originally develop such fetishes? | [
"There are several theories regarding atypical sexual behavior, so I'll give a quick summary of those that I know of. ",
"First is the courtship theory. This is based on the idea that normal sexual interactions involve a series of steps (courtship), and that somehow an exaggeration or distortion occurs at one of ... | [
"Doesn't all of this ignore the societal aspects - some societies find exposed breasts to be unbearably sexual, while others do not, and obviously a great deal of breast-focused fetishism would be more prevalent among a group where they are heavily sexualized, no?",
"I've always found it made sense to consider it... | [
"Wow, very interesting! Thank you!"
] |
[
"Is Saltation what causes ripples in both sand and clouds?"
] | [
false
] | I've done some cursory googling. It seems rippling in sand is called saltation. But I can't find anything that connects saltation to the phenomenon of ripples underwater and also ripples in clouds. To me they all seem connected, and saltation does define itself as a fluid moving over a substance (such as sand) so presumably that definition also applies for underwater and in the clouds. Just curious if anyone has seen these various appearances of rippling connected in any way? pictures: | [
"It seems rippling in sand is called saltation. ...and saltation does define itself as a fluid moving over a substance (such as sand)...",
"This is incorrect, ",
"saltation",
", at least in terms of its use in relation to bedforms (i.e. ripples, dunes) that form from sediment transport by a fluid, is a mechan... | [
"/u/CrustalTrudger",
" 's got the sand grain ripples side of this question, so I'll tackle the clouds.",
"Ripple patterns in clouds are typically caused by ",
"Kelvin-Helmholtz instability",
". This occurs whenever two fluid layers move past one another at different speeds. Any slight disturbance in the f... | [
"Fixed link for saltation:",
"https://en.wikipedia.org/wiki/Saltation_(geology)",
"For the purposes of this discussion, the key point is that saltation (Latin for \"leaping\") refers specifically to the way sediment grains can \"skip\" into the air after bouncing off the sediment surface. This is just one of s... |
[
"Does every layer of the atmosphere have the same angular velocity as earth's surface?"
] | [
false
] | By going higher in the atmosphere, gravity decreases but how does that effect atmosphere's angular velocity? | [
"No. The convective currents cause the atmosphere to circulate, and drive weather patterns. Angular velocity varies as a result.",
"Space does not impart significant rotational drag on the atmosphere counter to the rotation of the earth. The atmosphere doesn't \"lose angular velocity\" at altitude, if that's w... | [
"Yep, that's what I was asking. Thanks :D"
] | [
"are you cheating on a test right now?"
] |
[
"The coldest temperature recorded on earth is 183.8 kelvin, carbondioxide solidifies at 194.5 kelvin. Does this mean that the carbondioxide in the air turned solid and snowed down?"
] | [
false
] | null | [
"The vapour pressure of CO2 at -90°C is roughly 300 mmHg or 400 mbar (estimated from the graph on Wikipedia’s ",
"CO2 data page",
")). This is way higher than the partial pressure of CO2 in the earth’s atmosphere (410 ppm or 0.4 mbar), or even in exhaled breath (4% or 40 mbar). According to ",
"this Wikipedia... | [
"doesn't matter if it's h2o or co2, air can contain a certain amount even below their freezing points. you won't get co2 crystals forming in the air unless there's more of it in the air to begin with than the air can contain when the temperature drops to 183.8k."
] | [
"When we say something is at its \"freezing point\", we mean solid and gas can exist together. But that point depends on the pressure of the gas. 194.5 Kelvin is the temperature at which solid CO2 is in equilibrium with ",
" of CO2. But since CO2 makes up a small fraction of the air, its \"partial pressure\" i... |
[
"How did it hail in my country eventhough I'm at the equator?"
] | [
false
] | Not sure why I just remembered it, but a few years ago (2007/8 I think) it got really really hazy for about a month, it was so hazy we had to cover our mouths and noses with masks. I remember I was just sitting in my house having some lunch, then it started to hail?? The hail was circular and they looked like this in video. I think this is exactly the same hail storm I witnessed. If I'm not mistaken, it happened last year too. I live in Malaysia, temperatures range from 26c on good nights with rain and 40c on horrible afternoons. We also have monsoon season around Nov-Dec. Can someone explain how this happened? | [
"Hail happens when the temperature near the ground is above freezing, the temperature farther up is below freezing, and there are strong updrafts. Small ice particles fall down, and are coated in a thin coat of water. Then they are blown back upwards to where it is colder, and the water freezes, making the ball o... | [
"Okay so, let me try to understand this.",
"There were really strong winds blowing upwards as it was raining ice particles right? Then they get blown up again and it refreezes, then it falls again and this keeps repeating until it gets too heavy and falls to the ground.",
"So, hail can occur anywhere if there a... | [
"Large hailstones, usually golf-ball or larger, are typically a sign of impending tornado in areas prone to that sort of thing."
] |
[
"Is there a minimum wavelength in the EM spectrum?"
] | [
false
] | null | [
"There is no minimum."
] | [
"The energy approchaes infinity."
] | [
"Does anything special happen as the wavelength approaches 0 or does the energy just increase?"
] |
[
"Al Gore's AMA prompted me to ask a question, that I've thought about for a long time, about the global warming theory.."
] | [
false
] | null | [
"We haven't been ",
" climate data over the millions of years, but we have a decent idea of what the climate has been like using scientific methods. For example, we know that there have been several ",
"ice ages",
" in Earth's history."
] | [
"To elaborate on what cssher said. Based on many paleogeological studies, we've managed to paint a fairly accurate picture of what earth's temperature variance looked like over the last few hundred million years.",
"What we found that the temperature was largely cyclic. It had periods of high temperature that gav... | [
"so, all in all, the evidence of human activity on global warming is apparent and large. but there is a small, small, chance of hope that we didn't fuck everything up if it ends up being cyclic once more. just something i wanted to know :("
] |
[
"Can a rocky planet be Jupiter sized?"
] | [
false
] | In terms of mass, could such a world exist? Is there no way there would ever be that amount of mass available around a star? Are we just assuming all large planets detected are gas giants? | [
"Our prediction is no. According to Seagar et al 2007, for all common compositions, once a planet gets to a few hundred Earth masses adding more mass just compresses the interior more and the radius actually starts ",
".",
"https://www.planetary.org/space-images/mass-radius-diagram-wide-seager",
"Edit: Earthl... | [
"Wow, \"goldilocks\" indeed, that is way narrower of a margin than I realized."
] | [
"https://postureinfohub.com/can-you-stand-on-jupiter/",
"Tl;Dr sort of. ",
"We don't know if Jupiter has a solid core, but states of matter don't really work the same way at these pressures regardless. There's not a \"surface,\" but rather a transition from gas to liquid to solid very slowly. You'd get crushed ... |
[
"Does using a laptop regularly while it is on your lap do any damage?"
] | [
false
] | I always remember the speculation that keeping a laptop over your testicles/genital region often does damage. Is there any legitimacy to this statement? | [
"do you have any links for further information? specifically on the wi-fi being linked to DNA damage in sperm."
] | [
"First of all, this is not a place for speculation. Since you're not an expert and you gave a fairly vague answer, you're just speculating. The correct action in this case would not be to speculate on what could be the answer and let an expert correct you later, because the expert's answer would have been the sam... | [
"http://en.wikipedia.org/wiki/Erythema_ab_igne",
"I don't know about damage to genitalia/sperm/etc, but according to the Wikipedia article and it's cited sources, prolonged exposure to warm temperatures can cause a rash. ",
"Here's the portion on laptops:",
"Resting a laptop computer on the thigh (laptop comp... |
[
"AskScience AMA Special: We’re Carolyn Porco, imaging scientist on the New Horizons mission, and Miles O’Brien, veteran aerospace journalist. Ask us anything about New Horizons, Pluto, and beyond!"
] | [
false
] | Hi reddit! We are Carolyn Porco and Miles O’Brien, and we’re here to answer your questions about the New Horizons mission to Pluto and beyond. Thanks to and the for organizing this AMA. Carolyn Porco is the leader of the imaging science team on the Cassini mission presently in orbit around Saturn, and a veteran imaging scientist of the Voyager mission to the outer solar system in the 1980s. Miles O’Brien ( ) is a veteran freelance broadcast and web journalist who focuses on science, technology, and aerospace. He is a producer for NOVA and the science correspondent for PBS Newshour. | [
"Are you the Miles O'Brien from Star Trek? How often are you asked that? If you lived on a spaceship in the 24th century and got stuck back in time in the 21st, is this not the job you'd apply for?"
] | [
"first time! You are amazing."
] | [
"Are the images of pluto's smaller moons going to improve or are they just too small and/or far away from NH during the flyby? "
] |
[
"In the event of an heart attack why is it an either or decision between thrombolysis and angioplasty? Why can't both be done at the same time or successively?"
] | [
false
] | Non-native English speaker here. From what I understand, in the event of an ongoing heart attack the doctors must choose between thrombolysis or an angioplasty with stenting/PCI (PCI and Angioplasty are the same thing right?). But both cannot be done. So suppose someone is very far away from a hospital with angioplasty facilities. Why can't they be given thrombolysis first to save heart muscle and then when they reach the hospital after an hour they are treated with angioplasty with stents? Why does it have to be an either or decision? | [
"Mostly bleeding risk. Once you take those thrombolysis meds, your risk from complications from any intravenous activity shoots through the roof. Also, thrombolysis meds only work in a short window during the onset of a heart attack.\nSo it's more of a what's the best too for the job, not really an either or. "
] | [
"CAN be done, but not really done typically. The emergent period/damage to the heart tissue has already been done by the time the thrombolysis typically wears off. Usually the patient is then in a totally different care process that the doctor will manage. ",
"That being said, if the patient is deteriorating, man... | [
"Also, thrombolysis meds only work in a short window during the onset of a heart attack. ",
"So thrombolysis meds can be given first and then angioplasty done if the time needed to reach the hospital is about an hour?"
] |
[
"How are discoveries in psychology measured?"
] | [
false
] | null | [
"The general rule for psychology experiments is you need a p value of <0.05 which basically means that there's less than a 5% chance the found effects are the result of chance. Beyond that, effect size is also important. There are tonnes of different types of tests that show effect size or the level of relationship... | [
"It depends on the type of study you're doing. There's basically two different types; experimental and non-experimental (I'll leave out quasi-experimental but it's basically halfway between the two). ",
"In an experimental design, you're doing everything you can to eliminate all confounding (variables that you're... | [
"It depends on the type of study you're doing. There's basically two different types; experimental and non-experimental (I'll leave out quasi-experimental but it's basically halfway between the two). ",
"In an experimental design, you're doing everything you can to eliminate all confounding (variables that you're... |
[
"Does a permanent magnet have permanent net angular momentum while at rest?"
] | [
false
] | Since ferromagnetism is due to electron spin alignment, and since there is angular momentum associated with spin (in addition to the magnetic field), does that mean a kitchen magnet has a net angular momentum while at rest? If so, is it measurable with existing lab techniques (and further, has anyone done so?) It's odd to think there might be a slight gyroscopic effect to an object that is not moving.... | [
"Yes this is all true, you should read about the ",
"einstein-de haaas effect",
". You need a high sensitivity experiment though!"
] | [
"Thanks! Hadn't come across that one before... Very interesting. Somehow it's a little easier to wrap my mind around the idea of a coil inducing motion in a magnetic material (I guess I'm spoiled by induction motors, etc) than the concept of an inert stationary mass acting like a gyroscope (if only slightly). It ... | [
"I always like it when a question which I have wondered before comes up."
] |
[
"Does the age at which a species typically reproduces (relatively to the maximum age it can live) have any substantial effect at the rate it can evolve?"
] | [
false
] | Say a species lives in average for 10 years. Would it experiment any signs of evolution at a faster rate if it reproduced when it reached 2 years of age, as opposed to say 6? This is of course with the assumption that it has adapted for optimal conditions to reproduce at the ages mentioned, and with very little changes on its environment. To put it in another way, Group A reproduces at 2, while Group B reproduces at 6. Both live in the same environment, but can only reproduce with those of their group. Would one group evolve significantly faster (or slower) than the other just based on the time in their lifecycle they happen to reproduce? | [
"Absolutely. \nRemember that the rate of genetic change is not dependent on time but on number of generations. This is because the genetic drift occurs only at the next offspring, not the reproducing adult.",
"Thus, organisms that reproduce quicker (younger) are able to have many more generations, then adapt and ... | [
"If we assume all else is equal and there is heritable segregating genetic variation for the trait under selection, yes. More generations means more opportunities for selection to sample among the segregating variants. However if species (populations) differ in the amount of segregating variation, mutation rate, ef... | [
"This is part of why everyone is always scared of antibiotic resistance. Under the right conditions, bacteria can go through a generation every ten minutes. It takes years to develop a new antibiotic and a year is like eons for them."
] |
[
"Are there particle annihilations that result in other Bosons besides photons?"
] | [
false
] | When reading about particle collisions and annihilations, the most common example given is a collision with an electron and a positron, resulting in two high-energy photons. Are there other collisions which result in annihilations with different force-carrying particles? If so, does this imply that there is more to duality besides particle charge? | [
"Quarks can annihilate to gluons, and at high energies, particles can annihilate to Z bosons."
] | [
"Thank you for the in-depth explanation! I really appreciated the level you provided and the Feynman Diagrams to explain.",
"If I may ask,"
] | [
"Thank you for the in-depth explanation! I really appreciated the level you provided and the Feynman Diagrams to explain.",
"If I may ask,"
] |
[
"How can we know if an astronomical object is moving relative to us if Doppler effect is measured based in the proper wavelength emitted by the source?"
] | [
false
] | For example: how can we determine the blueshift of Andromeda galaxy if we never observed it standing still in our reference frame to know its proper emitted light wavelength? | [
"Because Andromeda is made of the same materials as we are, and we know how those things act in the lab. For example, hydrogen atoms have electrons that only can occupy specific energies, and when they transition between those energies, they emit or absorb photons of specific wavelengths. So we look at stars in And... | [
"We can look at the sun which is not moving much relative to us and see the absorption lines, then look at Andromeda and see how shifted those lines are"
] | [
"The spectrum of a light source contains patterns of bright and dark bands specific to the materials of which the light source is made. Those patterns shift towards blue or red depending on the amount of Doppler effect.",
"\n",
"https://en.wikipedia.org/wiki/Spectral_line"
] |
[
"Please help us, please, please, please help!"
] | [
false
] | null | [
"Go see a doctor, we're not letting this thread out. "
] | [
"I understand that, but we don't exactly have money to spare."
] | [
"we are obliged to follow the Reddit TOS which directly says we cannot give any kind of medical advice. There's nothing we can do on this forum. Sorry. "
] |
[
"Do arthropods experience emotions and/or pain, and how can we know that?"
] | [
false
] | Is there any new research on insects or other arthropods on this topic? Can they feel emotions and suffering in a similar way to mammals, even if their nervous systems are much simpler? | [
"As far as I'm aware, we don't have a good way of objectively describing, measuring, or comparing a subjective \"experience\". We know that they can detect a nociceptive (painful) stimulus and change their behavior to avoid the stimulus. We can even accurately simulate the entire nervous system of some simple arth... | [
"Look up \"OpenWorm\". We're still at a primitive stage but we're doing amazing things."
] | [
"I'm sorry, I only remember reading about a complete C. elegans simulation with 302 neurons several years ago and assumed that more advanced simulations have since been run. I actually don't know for sure and haven't looked into it since. I apologize if that was misleading."
] |
[
"How long does it take for tourniquets to start causing tissue damage?"
] | [
false
] | I know that applying a tourniquet leads to tissue damage by way of hypoxia, but I'm having difficulty finding an answer to this particular question. Also, can applying the tourniquet to an extremity also cause tissue damage in other parts of the body? | [
"I don't know of any good data on the issue, but for orthopedic surgery we will use a tourniquet for up to 2 hours at a time, which is generally considered low risk. We also try to keep tourniquet pressure to a minimum. After a recovery period, it is also considered safe to reapply the tourniquet, but there is no... | [
"8 hours seems pretty long. It's always a balance between risk and benefit, so if the risk is certain death by rapid exsanguination, exceeding 2 hours may be justified. However, ischemia (ie. lack of blood flow and everything that involves, including hypoxia) to the limb will cause large buildup of metabolites li... | [
"I had heard in my EMT class (I think that was where I heard it, hence the reason for posting here as I wanted to try to find clarification) that the risk of major tissue damage due to tourniquets is relatively low in general, despite the general perception. I had heard that you can be relatively safe about using o... |
[
"If I was on a planet who's sun emitted only light waves in non-visible frequencies to me, what would I see around me?"
] | [
false
] | Would it be black, white, or hazy? Would I be able to see some things around me or would seem to be in empty space? Cheers. | [
"It would be black, except if there are things on the planet that absorb that light and convert it to a visible frequency. Certain chemicals do this. You might see bioluminescence if any creatures exist. You might be able to see a little bit do to the starlight of other, normal stars."
] | [
"http://en.wikipedia.org/wiki/Nonlinear_optics",
"Frequency doubling, BAM! ;-)",
"Other than that, there really is no star emitting no visible radiation. Even brown dwarfs which can barely sustain any kind of fusion emit visible light (even if its only a little) so for the question we should suspend disbelief f... | [
"Absorb that light and convert it to a visible frequency",
"I don't know about this. From my limited (very limited) knowledge of how stars work, they emit a blackbody spectrum. (They can reach a certain energy of photon, then emit all photons [that don't get absorbed by the sun's atmosphere] of lower energy) F... |
[
"How do accents develop?"
] | [
false
] | [deleted] | [
"Naturally, as we are raised, our mouths begin to form so that we communicate comfortably with the vowels and sounds we’re used to. But when we’re confronted with a different environment with a different language and set of linguistics, our mouths struggle to perfectly imitate the sounds, thus, the accent is create... | [
"Why though do children say with parents that have a different accent to the natives develop the accent of the natives and not the parents? When for the first few years almost all the child's interaction is with the parents. "
] | [
"A study I heard about some years ago -- forget the details now, I'm sorry -- determined that accents are mainly socially influenced, and that certain kinds of people have more influence than others. Near or at the top were people who invited others into their homes to spend time with them and their families. An ex... |
[
"What percentage of the atoms in our bodies were in us a year ago? Ten years ago?"
] | [
false
] | null | [
"While most of your cells are constantly replaced, and even those that aren't will have a portion of their atoms exchanged through normal biological activity, some parts undergo exchange very slowly. For cells that don't divide and never get replaced, the DNA doesn't incorporate new, or lose old, atoms, unless they... | [
"Makes sense. Are you willing to tackle the percentage questions?"
] | [
"The way you would study this empirically is by putting uncommon isotopes into people's bodies and measuring the level of that isotope over time. For instance, ",
"99.8% of oxygen is oxygen-16",
", so what you could do is have them drink water with oxygen-17 in it and measure its concentration in their body at ... |
[
"Why are human reaction times so slow compared to other animals?"
] | [
false
] | null | [
"we aren't significantly slower in general. our reaction time from stimulus to action is similar to other animals of similar size. some pure carnivore predators are quicker reacting in specific ways, but we're faster in others.",
"size plays a big factor. a sparrow is going to have faster reflexes than an eagle, ... | [
"In what task?"
] | [
"Thanks! Couldn't ask for a better answer."
] |
[
"If I were to sit neck-deep in a tub full of whiskey, would I feel inebriated at all?"
] | [
false
] | For science! | [
"I believe alcohols will evaporate and you will be breathing it in. So yes?"
] | [
"This study in the BMJ",
" demonstrated that sitting with just your feet in a bath of vodka will not get you drunk. Extrapolating from that, I would go with no, assuming that all your orifices were plugged up. "
] | [
"I believe it would.",
"Diffusion",
" causes particles in high concentration to pass through a membrane to areas of low concentration. That's the manner by which your lungs absorb oxygen (and expel carbon dioxide), and also the manner in which the alcohol in an inebriated persons bloodstream makes its way into ... |
[
"Wouldn't it take a tremendous amount of fuel to mine an asteroid and transport that mineral back to earth?"
] | [
false
] | null | [
"Yes, and unless they happen to find an asteroid with an astounding amount of precious metals (gold, platinum, palladium, etc.) it is unlikely to be cost effective near-term to return the material to Earth. ",
"However, the (potentially) really exciting bit about this announcement is not bringing the material bac... | [
"I'm having trouble finding hard numbers, so I'm about to make several assumptions. They should all be reasonable though. ",
"Taking ",
"Zarya",
" as an example, which was the very first module of the International Space Station. It weighs about 20,000 kg which corresponds to a launch price of $200 million. T... | [
"There are two ideas to asteroid mining:",
"A) the one the wikipedia article explains quite well and that is you go there, get material, and bring it back. This can't be cost effect unless the price of say platinum goes up by an order of magnitude (at least)",
"B) You grab a 1000kg asteroid and place it in the ... |
[
"Why does sticking your fingers back your throat trigger your gag reflex, but swallowing food doesn't?"
] | [
false
] | null | [
"https://www.reddit.com/r/askscience/comments/171mp2/why_doesnt_eating_stimulate_our_gag_reflex/",
"Quote : \" I believe that swallowing is what's called a \"prepotent reflex.\" This means that it is essential for survival or avoiding harm, and is therefore given the ability to override other competing reflexes, ... | [
"This answer is fine, but one could guess that it's because swallowing is important. I wouldn't mind reading more about the mechanism of the \"override\" if someone has those details! "
] | [
"Yeah, as is it doesn't really answer the question.",
"\"Why doesn't swallowing trigger the gag reflex?\"",
"\"Because the gag reflex doesn't trigger while swallowing.\"",
"Cool, thanks! "
] |
[
"How much more radiation was on earth when life first formed?"
] | [
false
] | Of various radioactive isotopes created from supernova(e), assuming additional elements did not become radioactive until the earth was formed or otherwise collided with the earth, how much more radioactive was the earth's atmosphere when life first started than there is today? | [
"This is getting off topic so I'm going to message you."
] | [
"Well we think that life started ~4 billion years ago and we don't have a lot of information about Earth's atmosphere at that time. So unfortunately there is no answer to your question. However, I expect just off the top of my head that it would be fairly similar if not a little lower because solar activity was a b... | [
"But would there would be more radioactive isotopes on earth that have now since decayed?"
] |
[
"What is the point of Variance?"
] | [
false
] | I understand that it is the Standard deviation squared, but what is it actually used for? | [
"Variation is much easier to compute directly in many situations, and has a more 'natural' definition when building up from discrete probability. They both measure distribution, and while standard deviation is commonly used as a quick measure of distribution for experimental data, variance is (at lease when I've se... | [
"This",
" is a great place to start. \nI can't possibly pretend to be familiar with a variety of math research, but it arises fairly naturally from the expectation in combinatorics and probability and is simple to compute using moment generating functions. Standard deviation may be nice for getting an idea of a c... | [
"Thanks! You mentioned that variance is more useful for theoretical work. Why exactly is that?"
] |
[
"I want to clarify the nature of Planck's constant and its relation to wave functions in light..."
] | [
false
] | There is a fundamental misunderstanding on my part about Planck's constant. I cannot wrap my head around the origins of why it exists... I've looked at the Wiki, I have seen diagrams of Photons bouncing against each other when a limited amount of space, I have considered the relationship of specific particles and what parts of the light spectrum those particles emit...but Im lost. In the simplest terms, can someone explain what the primary observations are/were that defined Planck's constant? | [
"In the simplest terms, can someone explain what the primary observations are/were that defined Planck's constant?",
"This is a truly excellent question.",
"Planck's constant was invented to explain exactly how hot objects give off radiation, like a glowing filament in a light bulb. I will use this example to e... | [
"...So, does this (with Planck's constant) explain how you can use spectroscopy to identify the elements present in a light source?",
"Not really. If you get a jar full of some element, say hydrogen, and stimulate it by driving electrical current through it you will see that it ",
"emits light at specific wavel... | [
"/u/DanielSank",
" already wrote about Planck's constant in the relationship between energy and frequency, but it has another role: the fundamental amount of angular momentum in the universe is half of Planck's (reduced) constant. That means particles can only have 0, h/2, h, 3/2 h, 2h etc angular momentum but no... |
[
"With light produced in the Sun's core, does it move slower than the light that's present at the surface? Or is it all mostly the same speed?"
] | [
false
] | null | [
"Light does travel slower in a medium. Note that when we say things like \"in special relativity, the speed of light is the same for all observers\", we are talking about the speed of light ",
", i.e. under idealised circumstances. The speed that a pulse of light moves at will depend on the medium it's going thro... | [
"A medium contains atoms / molecules. A vacuum (in this case) doesn't have anything.",
"When you look at what the light does in the medium, i.e how it's transmitted and how it actually travels, it gets super technical. But if you don't worry about how it's traveling, it's a ton more simple. ",
"When light trave... | [
"That's the trouble lol, it's complicated, mostly because the mathmatical models that describe the hypothesis don't work for all cases. ",
"You could say that the molecules absorb and then emit the light, like a game of telephone, but that model says the light should slow down further than it does, and that it sh... |
[
"Evolution: What findings, if they would be discovered, would completely disprove Evolution, or at least significantly disturb the existing model?"
] | [
false
] | [deleted] | [
"Well evolution is about more than just chronology. It's also about heredity and genetics. There were any number of creatures dreamed up in ancient mythology that would be seriously disturb our understanding of evolution if found. For example, if in some remote jungle, tomorrow they discovered a living, breathing g... | [
"Fossils of dinosaurs with arrowheads stuck in them?",
"A fossil of a triceratops holding an autographed photo of Kirk Cameron?"
] | [
"God/aliens coming down from the sky and creating a new species and stating that previous species were created by them. (And not through some middle-man prophet or ancient book.)"
] |
[
"What's going on in your throat/voice box when you lose your voice?"
] | [
false
] | I am losing my voice from a cough. Why and how does this happen? What's going on in there? | [
"Doctorate in voice here.... regarding laryngitis from overuse of the voice: the cords vibrate against each other to create sound, much like if you tried to make a trumpet sound with your lips. The cords are essentially rubbing against each other several hundred times per second; that is the basis of phonation. O... | [
"im pretty sure its from inflamation from overuse, causing it to not be able to vibrate and produce sounds."
] | [
"The relevant ",
"wiki article",
" agrees with you. The \"Causes\" section has several sources supporting that inflammation from overuse will cause laryngitis, but a very cursory examination doesn't explain the mechanism behind this, which I feel would be much more interesting. Do you (or anyone else) have in... |
[
"How did the early solar system sort itself out?"
] | [
false
] | Why did the lightest gas, hydrogen, migrate to the center of the “dust cloud?” Why are the rocky planets and the asteroids next, then more gases to form the gas giant planets? It seems the original disc/cloud was complex, so how did it sort? Was it homogeneous initially? | [
"Yes, you start with basically a homogeneous cloud, which is mostly hydrogen, followed by helium, and then a sprinkling of everything else. ",
"This composition is what you then get for the Sun, in the center. This composition is also what you start with everywhere else in the cloud.",
"The cloud has heated u... | [
"As a tack on to this answer the initial perturbation that causes the homogeneous gas cloud to have a locally dense pocket, which acts as the \"star seed\" for the rest of the cloud to be drawn towards, is thought to often be the result of gravitational disturbances from passing celestial bodies or the explosive de... | [
"The way I understand it, the extra piece is ",
"planetary migration",
", which is part of the ",
"Nice model",
", the most popular model for the formation and evolution of the Solar System. That doesn't invalidate anything ",
"u/HappyFailure",
" said, though."
] |
[
"Is brown rice really a more \"healthy\" choice than white rice?"
] | [
false
] | null | [
"Brown rice naturally has more nutrients like vitamin B and iron, but when making \"enriched\" white rice they usually add them back in. Still, white rice usually doesn't have any magnesium. Also, there's twice as much fiber in brown rice, which is a significant amount considering its health benefits. Also, brown r... | [
"brown rice impairs magnesium retention",
"Cullumbine H, et al. Mineral Metabolism on Rice Diets. British Journal of Nutrition, 1950;"
] | [
"No. People often believe it is as it is less processed but this is an appeal to nature fallacy. In actuality it has worse nutrient bioavailability, more anti nutrients, and more arsenic.",
"Cullumbine H, et al. Mineral Metabolism on Rice Diets. British Journal of Nutrition, 1950;",
"Rama Rao G, et al. The Effe... |
[
"What is \"herd immunity\"? Is this term being thrown around correctly? Is this a viable solution to Covid19?"
] | [
false
] | null | [
"Herd immunity is when there are so many people that are immune to a disease that infectious people aren't able to spread the disease further. If you are infected but everyone around you is already immune to the disease you can't infect anyone else. ",
"It is not a solution to Covid-19. It is a desired endstate. ... | [
"What is \"herd immunity\"?",
"When most people are immune so it becomes unlikely for a pathogen to come into contact with people who aren't, because it can't simply jump through the population in general.",
"Is this term being thrown around correctly?",
"Doesn't look like it, much of the current discourse se... | [
"Good explaination but I think that it is important to expand on the \"we don't know how long the immunity lasts\" point.",
"If the immunization lasts, Say 5 year, with a vaccine we can just re-do the the vaccination every 5 years, no big deal.",
"If we reach herd immunity \"naturally\" every 5 years we are bac... |
[
"Is there a practical application of the fact that there are distinct degrees of infinity?"
] | [
false
] | I recently learned that there are different degrees of infinity -- e.g., countably infinite sets vs. unaccountably infinite sets. This is certainly interesting from a "curiosity" point of view, but is there a practical application of this knowledge? Can you explain to me whether this fact is an inconsequential mathematical technicality, or if it there are conceivable engineering applications that could be affected by it? | [
"Yes and no. For example: in science and engineering, one of the most important mathematical tools we have is calculus. Calculus relies on certain properties of the real/complex numbers, for example you cannot define a derivative as a limit if you are using the integers (which are countably infinite) because the ep... | [
"From a computer science point of view, countable sets are really the only thing we can deal with. Because computers are digital, the number of different values they can represent are always countable - even if we assume that we have unbounded resources (e.g. time and memory).",
"So for example, given enough reso... | [
"Outside of computer science, it is not directly important. I don't think any structure has been built using the consequences of countability. But countability and uncountability are so important in the mathematics that were put into building the structure that they are very relevant."
] |
[
"Thanks, r/askscience"
] | [
false
] | null | [
"Understood, however meant it more in terms of everyone who comments and has input in general"
] | [
"We appreciate the comment :) But \"message the moderators\" on the right side-bar is the way to contact us."
] | [
"Well, as commenter/inputter, thank you again :P"
] |
[
"If a woman has an irregular period, let's say once every five months, does she extend her birthing years?"
] | [
false
] | [deleted] | [
"You have this a little backward. You're correct in that the they are born with their set amount and they do get older.",
"There isn't a hormonal change that triggers menopause. What happens -- through mechanisms we don't totally understand yet -- is that when you are younger the eggs initially released were the ... | [
"You have this a little backward. You're correct in that the they are born with their set amount and they do get older.",
"There isn't a hormonal change that triggers menopause. What happens -- through mechanisms we don't totally understand yet -- is that when you are younger the eggs initially released were the ... | [
"I disagree with the idea that women don't \"run out of eggs\" during their lives, as the other commenter suggests.",
"The current consensus is that the hormonal irregularity of menopause is a kind of retrospective marker of the depletion of ovarian follicles. The age of ovarian follicle depletion is based on the... |
[
"How accepted is the quantum theory?"
] | [
false
] | null | [
"What do you mean by \"the quantum theory\"? Quantum mechanics is accepted by every serious physicist on the planet."
] | [
"doesnt quantum mechanics imply that us looking at something impacts it? with the double slit experiment making it seem as though nothing really \"exists\" until we see it. i know eintsein said something like \"i believe the moon is there even when im not looking\" I am kind of trying to make sense of the implicat... | [
"QM has many counterintuitive implications (many of which get exaggerated or misrepresented in popular science media). But it is very well supported by experimental evidence. It is definitely a more accurate model of reality than classical mechanics, any physicist will agree with that."
] |
[
"What's the real-life use of solubility product constant?"
] | [
false
] | I searched and searched but I could not find a real-life use of solubility product constant. I saw that water filtration requires solubility, however, it does not need the Ksp value, whose real-life application I am looking for. Thanks in advance. | [
"Ksp helps you determine the strength of the common-ion effect for any given substance. The common-ion effect is important in all kinds of industrial processes involving purification by precipitation. Ksp is also useful in explaining the formation of particular minerals. "
] | [
"Imagine you have a mixed solution of the nitrates of Sr",
" and Ba",
" and want to separate the two ions. Both of their sulfates are pretty much insoluble in pure water, so as you add a sodium sulfate solution, the sulfates precipitate. You can use the Ksp values to determine the composition of the precipitate... | [
"Why would one require Ksp value for purification?"
] |
[
"Can anterograde amnesia be used as an anesthetic?"
] | [
false
] | I was reading on Wikipedia that a variety of drugs can induce anterograde amnesia, and it occurred to me: has anyone ever used this as an anesthetic? For example, if a patient was given an amnesia-inducing drug before surgery, would that person fail to remember the pain, therefore making it not actually matter if that person were sedated? | [
"As a sole anesthetic, never. Amnestics are part of the balanced anesthesia care model and can help when the anesthetic has to be light because the person is physiologically unstable. However, there are other factors to be concerned about than just recall of the surgery. Painful stimuli produces a huge surge of cat... | [
"I assume the fact that the patient would be squirming about would also be a factor?"
] | [
"It really depends on the surgery. Not all surgeries require neuromuscular blockers (paralytics), but you're right in that benzodiazepines don't give adequate surgical muscle relaxation. So if it were a surgery that required relaxation, that's another reason that amnestics only wouldn't be enough."
] |
[
"How come gases are so cold in their pressurised cans?"
] | [
false
] | null | [
"The gas in a can like spray paint isn't actually cold. Its the same temperature as the can or the air around it. Its when the gas is rapidly expanded that the temperature drop happens. The opposite is also true. When you compress a gas it heats up. Its what makes most air conditioning systems possible. "
] | [
"It's not simply compression and expansion. It is the phase change from liquid to vapour that causes the biggest change in temperature. This is true for refrigeration system as well."
] | [
"Chemist here. I actually did a lab experiment analyzing the Joule-Thomson effect (the exact effect you are describing.) This is sometimes known as the \"throttling process\", and as mentioned in another comment, is frequently utilized in refrigerants and other cooling processes.",
"As a gas expands in this manne... |
[
"If the earth's atmosphere was compressed into a liquid, how would it compare in volume to the oceans?"
] | [
false
] | null | [
"Perhaps a bit surprisingly, it's really not that much. The total mass of all gases in the atmosphere comes out to 5.15*10",
" kg. Since most of this gas (~80%) consists of nitrogen, let's use the density of liquid nitrogen, which is 0.807 kg/L. Dividing the two numbers we get, 6.4*10",
" L. This may sound like... | [
"For another way of looking at it, if you spread that throughout the earth it would be about 12.5 meters deep."
] | [
"The atmosphere as a liquid would be less dense than water so it takes more depth to exert the same force."
] |
[
"could life be created and sustained without a planet?"
] | [
false
] | I was reading an article on cracked . It says that there's a huge water cloud. My question is Could life be created in this water cloud or another water cloud in space. If life could be created, could it even be sustained? | [
"Life as we know it, (carbon based) could not, now that being said, that doesn't mean that life couldn't be based on something like silicon (",
": Silicon based life would be possible at extremely low temperatures, ( lower than -100ºF). Problem being is that water wouldn't be liquid in a cloud in space, in order ... | [
"Really appreciate the detailed response. Thanks again!"
] | [
"No problem glad to help!"
] |
[
"Why do knots seem to form \"easily\"?"
] | [
false
] | [deleted] | [
"Basically it is much more likely for a string to fall in a knotted positing than a un-knotted one. Also, once a string is knotted it resists being untied (which is the basically the definition of a knot) so it'll remain knotted until someone unties it.",
"Here's a study about it ",
"http://physics.ucsd.edu/~de... | [
"I think the US army did a study on this at one time. Tried to calculate the likelihood of knots forming and difficulty in untangling them. To me this may have been futile as the variables are too great.",
"Ultimately I think it comes down to this. For any cord, there are many combinations for a knot/knots to for... | [
"That is exactly it: topologically speaking there are a huge number of configurations we call knots, and only 1 possible configuration that is not a knot."
] |
[
"Why do mitochondria need their own DNA?"
] | [
false
] | null | [
"As has been said, endosymbiotic theory which is pretty widely accepted states that both chloroplasts and mitochondria were once bacteria of their own right. We believe the modern day equivalents are cyanobacteria and proteobacteria respectively.",
"Some nice sets of evidence:",
"Circular genomes as seen in bac... | [
"Complete mitochondria (like those found in humans, plants and most eukaryotes) do seem to need mitochondrial DNA (mtDNA) to keep their distinctive shape. Yeast cells that lack mtDNA (known as rho0 cells) have abnormal mitochondrial morphology. But the number of mitochondria do not differ between rho0 and rho+ ce... | [
"Certainly. Lynn Margulis gave the theory the boost it needed back in the 60s. She didn't really help her cause in the 80s when she tried to attribute most organelles to endosymbiotic theory in addition to her (later) views on HIV. Unfortunately it's often the case that when a perfectly good idea is proposed by som... |
[
"If Jupiter is a gas planet made up of Hydrogen and Helium, could it turn into a star if parts of it were heated enough to start nuclear fusion?"
] | [
false
] | I just wondered | [
"Jupiter needs to be about 80 times as big as it currently is for that to happen. It only needs to be about ~13 times as big to start burning deuterium."
] | [
"I believe that the issue is not heating, but compression. Thus you would need to add mass, not energy to make it a star."
] | [
"Jupiter lacks the required numbers of atoms to start a proper nuclear reaction. With more atoms, Jupiter would gain more gravity; then, \nit could begin to contract under its own gravity, setting off the process which will convert it into a star (or, to be precise, a Protostar, which is not a real star).",
"So, ... |
[
"If I am paragliding through dark clouds, would I be able to fill up an empty waterbottle?"
] | [
false
] | Say I glide through storm clouds and was able to to keep altitude until I got out of it. Would I be able to catch water? Would I be wet when I got out? Is the water safe to drink? | [
"Well I do sailplane gliding quite regularly on top of having a pilot's licence(on top of what seems to be the prerequisite of being in this sub; a physics major), and yes, it does get the windscreen wet if you pass through cloud. As a matter of fact the water droplets adversely affect glide performance so as a gli... | [
"By storm clouds i presume you mean cumulonimbus? You'd be crazy to touch those, even the big boys in the airlines steer clear. But for the sake of this thought experiment, I assume you are.",
"Why's that, stronger winds/electrical charges lead to an unsafe environment?"
] | [
"The purity would be related to air quality, but even dirty air would be ok to drink. You might not want to do it regularly though. It depends on the contaminants that make it into the water. If it's just low pH as a result of SOx and NOx (acid rain), then you'll be fine as people drink things that are way more aci... |
[
"Why is it more difficult to breathe warm air?"
] | [
false
] | When I get into my car when the sun has been baking it all day, I feel like I can barely fill my lungs. In cool air, though, breathing is much more comfortable. Why is body-temperature air stifling vs cooler air? | [
"It’s not harder to breath, but there is less oxygen per volume of hot air compared to cold air. Cold gases are denser, meaning more oxygen per volume, your body feels this lack of oxygen in the air and tells you to breath harder to make sure you continue to get the requisite amount of oxygen that your body needs t... | [
"I’m no expert but warm air has higher temperature so your lungs don’t feel much change in temperature because it is already warm. But if it is cold then you can notice the difference more and thus feel like you have indeed received air. Also the warm air is sometime more humid so it may be thicker and thus more di... | [
"Warm air moves the oxygen dissociation curve the wrong direction also and makes it harder for your lungs to release CO2 and absorb O2"
] |
[
"Why does hair turn grey / white when mammals get older?"
] | [
false
] | Beyond just the obvious reasons (lack of melanin), what triggers in the body make this occur and why? | [
"I'd be interested to here from someone who actually works closer to this than I,but here is the ",
"Wiki",
" article on the subject. ",
"\" The change in hair color occurs when melanin ceases to be produced in the hair root and new hairs grow in without pigment. The stem cells at the base of hair follicles ... | [
"So it is a matter of the lack of melanocytes? Are all melanocyte stem cells used up at a certain point? ",
"I'm less interested on how this happens and more in why it occurs."
] | [
"It's probably related to ",
"Telomeres",
", but that more of the \"How\" then the \"Why.\" ",
"The \"Why\" falls under the evolutionary biology heading more, and there is always the general \"because it allows offspring to better survive.\" That's hardly a real explanation however. ",
"This is the same ... |
[
"Is there anyway to take heat and turn it into electricity?"
] | [
false
] | null | [
"In principle, yes. A heat engine is a device that takes heat from a hot object and moves it to a colder object. In the process we can extract some work from it, usually by expanding and contracting gases appropriately and making the gas move something mechanical. If you want electricity, you then have to turn the ... | [
"Look up thermionic generators. Several ways of doing it. Basically a junction that is cold on one side and hot on the other creates a potential and moves current if a complete circuit is available. Have you seen those picnic coolers that have a little fan on one side and plug into your car's 12 volt system? When y... | [
"A Stirling engine can operate on as little as a 0.5 K temperature difference, can use practically anything as a heat source, and can approach efficiencies as high as 30%. You would need to gear one to a generator somehow, and I don't know as much about those. ",
"http://en.wikipedia.org/wiki/Stirling_engine"
] |
[
"Why are burns more prone to infection than lacerations or abrasions?"
] | [
false
] | I was under the impression that the biggest threat with a burn is infection, why is that? | [
"Depending on how serious the burn is, it can destroy the skin to various depths. Thus opening the barrier that was there to keep infections away (notice how permeable your skin becomes at the burn site, it usually becomes shiny and wet as your plasma leaks out). Burns tend to have a bigger surface area than the ot... | [
"Actually, a lot of the bacteria that are considered \"normal flora\" that inhabit the surface of your skin can cause quite serious complications if they get into areas that they're not supposed to. For example, staphylococcus aureus likes to colonize the nose and throat and doesn't cause problems (usually). But if... | [
"Burns have two major problems relating to infection 1) typically the local immune response is destroyed, compromising the ability of the body to keep out foreign invaders since the skin is the major defense 2) Burns do not clean themselves out. The body is made to react to cuts, a very intricate system starts occu... |
[
"What does the Schrodinger's equation give me exactly?"
] | [
false
] | null | [
"Hi yousif777 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 follo... | [
"i am new to reddit, what is a flair"
] | [
"It is the category that we assign in this subreddit to each question, like \"Chemistry\" or \"Biology\". This helps users and panelists sort questions by category. Please see the auto-generated comment above about instructions for adding flair."
] |
[
"Is blood letting an effective form of reducing blood pressure?"
] | [
false
] | null | [
"Yes and no. In the acute sense, it's very effective in the sense that removing blood from an otherwise closed system will by definition drop the pressure. It, however, in no way tackles any underlying chronic cause of high BP. "
] | [
"I'm not a medic, just a humble biochemist, but my understanding is this. You restore blood volume, and therefore pressure, very quickly - just osmotic movement restoring plasma volume. But restoring the non-aqueous content (both cellular and other components like platelets) takes longer. ",
"So I suspect you (hy... | [
"This. You'd end up pancytopenic very quickly. "
] |
[
"Can we ever expect to see the inner layers of Earth?"
] | [
false
] | I'm guessing it's very doubtful, but I'm curious to know if there are any technologies in development that could make it plausible in the future. | [
"I'm not sure what you mean by \"see\" here, could you please elaborate?"
] | [
"I'm pretty sure that he/she means ",
"this",
".",
"I'm sure that we'll find a way to drill into the mantle and see it (using cameras or bringing up samples for testing), but humankind will never be able to reach the inner core or outer core. The pressure and heat at those depths is just too great for drills... | [
"There are some environments, such as mountain belts, where broad cross sections several km wide of the earth crust are exposed. These sections are thouroughly deformed and fractured, but we can make sense of them. In some cases, such as ophiolitic complexes, the section goes all the way down to the upper mantle. F... |
[
"Can a star be so hot it is invisible to the naked eye?"
] | [
false
] | The hotter a star is the higher the frequency at which it glows. So can it be so hot that it is 'glowing' at x-ray frequency and is invisible to normal light? | [
"No. As temperature increases, the intensity of every wavelength always and only increases. Different wavelengths increase more than others, causing the peak to shift, but still the intensity everywhere increases. If it's glowing at X-ray frequencies, it also glowing quite brightly in the visible as well."
] | [
"The tail end of the blackbody spectrum would still be strong enough in the blue for a person to see. This is similar to Cerenkov radiation: most of it is in invisible wavelengths, but we still see it as blue."
] | [
"Exactly. It's just that it's also glowing even more in the blue range, too."
] |
[
"Are their any risks to life expectancy for patients who receive donor organs that are older than their age?"
] | [
false
] | So I have a question. Does putting an older person’s organs in a younger patient have any risks? Like, would someone who was say 12 years old have the same average life expectancy if they were to have the heart of someone who gave their organ at say 35 years old+? | [
"Getting a transplant shortens your lifespan significantly, regardless of the donor (except, perhaps, from an identical twin, but even then it may)",
"The thing is, it shortens your lifespan much less than the disease which was killing you would have. So on balance, it adds to you lifespan, but not nearly as much... | [
"The average heart transplant lasts ten years and may last twenty. Transplants do not repair people or make them healthy again. Transplant recipients are constantly fighting rejection -- their body attacks the foreign organ. The medicines they have to take to slow rejection cause a lot of side-effects and often inj... | [
"Another thing to consider is the fact that anti-rejection medications increase the risk of various cancers. This is because medications given to organ recipients are immunosuppressive - they keep the body’s immune system from attacking foreign tissue. However, it is this same immune system that protects us from ca... |
[
"On the Wikipedia page for \"Koch's postulates\" it is stated that HIV causing AIDS doesn't follow from them. How so?"
] | [
false
] | Under . | [
"Koch's Postulates mainly apply to bacteria, fungi, and protozoans. The Postulates require that you are able to take samples from an infected individual, isolate them in culture, reintroduce them to a healthy individual, and recreate the disease. This breaks down for viruses at the \"culture\" stage. Unlike living ... | [
"When ever you read something on Wikipedia it is important to look at the source and verify. The statement you quoted is cited as coming from a Nature article published in 1990. It discusses the Duesberg hypothesis, that argues for an alternate cause of AIDS. Either recreational drugs or the potent anti-viral dru... | [
"As it states earlier, his postulates are mostly obsolete as the field of virology formed and made more sense of things. HIV causing aids doesn't follow his postulates, which is an example of why they're mostly obsolete."
] |
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