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[
"AskScience FAQ Friday!"
] | [
false
] | Welcome to , our new weekly feature highlighting some of the most frequently asked questions on ! We'll be posting a different FAQ each week and opening up the thread for follow-up questions and discussion. We're starting things off with an astronomy question: One of the most common misconceptions about the expanding U... | [
"How does accelerating expansion fit into this? That would seem to imply that there is actually some \"upward force\" pushing things apart?"
] | [
"Not really. The main thing I wanted to get across with this answer was that space isn't expanding everywhere, only \"overcome\" by other forces. If you're in a region where the Universe isn't expanding, there's no expansion, period, just like a ball that was thrown in the air and fell back to the ground isn't tryi... | [
"Are the fundamental forces what keeps matter from expanding along with space?"
] |
[
"Why is hot water \"cloudy\" in the glass but becomes clearer as it cools down?"
] | [
false
] | null | [
"It has to do with the solubility of gases in the water. Hot water has a lower gas solubility than cold water, so when you take cold water that is saturated with gas, then heat it up, the gas will come out of the solution, making a cloudy appearance to the water.",
"As the temperature drops, the solubility incre... | [
"Thanks!"
] | [
"I suppose that is at one atmosphere, at 78% composition. If I interpret that correctly, a liter of water at 4°C is about a one molar solution of N",
". That's interesting considering that in its gaseous form, it would occupy a space about 23 times greater."
] |
[
"Specific minimum distance for a 1s electron?"
] | [
false
] | I know, I know; this is a shameful gap in my knowledge as an upper division science student, but I couldn't immediately come up with the answer, and my notes from gen chem contained little that I didn't think would be tested (a pox on younger me). I realize the mean radius of a 1s orbital will be stupidly small, but is... | [
"If I'm getting what you're saying correctly, the electrons (s orbital ones) can exist anywhere that isn't entirely occupied by the mass of protons and neutrons, with no repulsion from spaces close to it otherwise?",
"Well, technically the S, P, D and so on orbitals are only approximations that we get by ignoring... | [
"There is no lower bound.",
"In any orbital, the probability of finding the electron in any neighborhood of the origin is nonzero. In the non-S orbitals the probability density ",
" the origin is zero, but for the S orbitals even that is positive."
] | [
"Electrons and protons can actually occupy the same space, because they're different particles. Kind of counterintuitive.",
"It's actually possible for the electron to get \"captured\" by the proton and produce a neutron and a neutrino, but I'm unaware if this has been observed in plain hydrogen."
] |
[
"Is there any way to measure the intensity of an emotional experience?"
] | [
false
] | I can compare two experiences, say looking at a painting and eating a meal, and say that I enjoyed both but preferred one over the other. Is there a way to measure this enjoyment? Furthermore, are there some emotions that we are able to better measure than others? | [
"It's a difficult question. Emotional intensity depends on many factors. If you're lost in the woods, a kind stranger with a map and a GPS can elicit very intense emotions in one. The same stranger passing you on the street probably wouldn't even be noticed by you at all. So we could say that desperation or need is... | [
"Well, with science we can measure dopamine and oxytocin. ",
"Non verbal cues- flushing, widened pupils, faster breathing. Would Indicate excitement/arousal. \nMeanwhile- fear and sadness have subtle facial movements and eye reactions/eye movement. ",
"Check out body language. Most of human communication is no... | [
"It's a huge area of debate, and it will depend heavily on the emotion you're discussing. For example: ",
"Some people argue that discrete emotions (e.g. happy, sad, angry, afraid) don't even really exist. Other people argue pretty much all emotions are discrete and definable. Some people are in between, and ... |
[
"When did \"sleeping\" evolve? What are the most primitive organisms that we know of that sleep?"
] | [
false
] | Was reading an askreddit thread about "weird and common things" and sleeping is brought up. It still seems so strange to me that organisms evolved the need for sleep. For one thing it makes us completely vulnerable to predators. Do we have any idea when this habit first appeared in the evolutionary timeline? | [
"Tangent question, is sleep what evolved or the state of being awake? As in, did multicellular organisms first evolve to walk around, eat, reproduce, then sleep and recover.. or did they evolve to stay in a neutral state then get up, eat, and reproduce? "
] | [
"Sure! Most organisms contain circadian clocks. This allows them to keep approximately 24-hour time even in the absence of any environmental time cues. Ordinarily circadian clocks are synchronized to environmental time cues, such as light/dark or temperature cycles.",
"Circadian clocks time everything from gene e... | [
"Probably neither. Organisms evolved circadian (and possibly other) rhythms first, so there was never a uniform pattern of cellular activity across the day in multicellular organisms."
] |
[
"Are the \"Three Laws of Robotics\" something that will actually be applied to AI in the future?"
] | [
false
] | If so, what are the chances that it will work forever? | [
"Those laws are very flawed, and don't answer how to deal with moral conflicts.",
"Which, I believe, was the whole point of the series."
] | [
"This question is essentially unanswerable, because we don't know enough about what true AI would be like, if we were able to create it.",
"Nevertheless, I think the answer you're looking for is 'maybe, but only incidentally'. There's nothing particularly special about the laws as a way of protecting humans - wik... | [
"Those laws are very flawed, and don't answer how to deal with moral conflicts.",
"They would not be used by any practical AI designer."
] |
[
"Would the Moon be a good location for a telescope?"
] | [
false
] | Would there be any benefit to building a telescope on solid ground versus floating through space? Would the Moon's atmosphere be enough to have any effect? | [
"Not only possible but has been ",
"suggested",
" that robotic landers deploy such a thing. It is likely that it will not only be desirable to have radio telescopes on the Moon at some point but it may actually become necessary. The far side of the Moon is likely to soon become the only place we can be free of ... | [
"I can think of several disadvantages of a lunar scope vs a space-based telescope:",
"A lunar scope has to land and deploy on the moon, adding significant cost and risk.",
"The moon blocks half of the sky. This is also a problem for LEO telescopes and the Earth (Hubble) and is one of the reasons why The Webb te... | [
"Wouldn't dust be a problem?"
] |
[
"Does the weight of food have any bearing on its caloric density?"
] | [
false
] | Like the title says, obviously there isn't necessarily a clear '1 kg of food = X calories', as it's easy to come up with a counter example. However, is there relationship there? I have a hard time imagining a 1000 calorie bit of semi-dense foam (think like a 100 cm3 cube of foam?), but I can imagine eating a (comparati... | [
"Not entirely but it does happen often that heavy, dense foods tend to have more calories than light foods mainly because most light foods have water in them. For instance 5oz of chicken breast is about 230 calories. 5oz of broccoli is around 50 calories. Same weight, big calorie difference. "
] | [
"I think you mean cubic centimeters (cm3). Trying to visualize the question. In some ways weight can correlate with calories just by suggesting a higher density. A lot of the highest calorie foods will be dense with sugars or fats like your butter example. However foods can also be dense with water and plant fi... | [
"It depends on the compositions and how much of it is digest able. Some foods are full of water like cucumbers, and they don’t have much calories. A price of bacon is almost all fat with little water, which makes it more energy dense "
] |
[
"Can our brain know what time it is while we're asleep?"
] | [
false
] | Is our biological clock aware of the solar clock? | [
"Yes! Each cell has a set of specific genes which are transcribed and/or translated rhythmically. For most people, each cycle takes about ~24.3 hours. This coincides with day length and is known as your body's circadian period. As it's slightly longer than 24 hours your body needs to keep re-adjusting to changing d... | [
"Right, so that's actually a very difficult question. In essence, the main control genes which are activated by light actually promote lots of downstream effects in different cells and tissues. The SCN is a collection of cells and so it communicates as other nerve cells do (i.e. deplolarisation or neuronal firing).... | [
"Also the stream of information isn't 'constant' in that sense. Seeing light in the morning will entrain you to your external environment, but it only takes that one instance of light (assuming it is of moderate intensity and duration) to let your body know it is awake at the correct time. The SCN is actually very ... |
[
"Why does the combusting side of a log segment into squares? Also, elementally speaking, what is the white ash that remains?"
] | [
false
] | null | [
"It doesn't segment into squares. It segments into rectangles. This seems like a bit of a nit-pick, but it's important. The reason is the grain of the wood. The longitudinal (along the length of the log) splits are due to the grain breaking open.",
"After this has occurred, and as the structural integrity of ... | [
"The chemical composition of ash varies depending on what was in the wood, as you might expect. ",
"This article",
" shows that the elemental content of the ash of several types of wood or bark is primarily calcium, potassium, and magnesium, plus lower amounts of other elements (document page number 111). The... | [
"In fact, potassium was first isolated (and then named) from potash- the ashes of plant matter.",
"As ",
"/u/ArcFurnace",
" mentioned, carbonates are formed during low temperature combustion... CaCO3 being the primary component. But at higher temperatures, you will drive off carbon dioxide and be left with Ca... |
[
"Why does hematite exist in gray and red varieties?"
] | [
false
] | I'd assume that the red variety is oxidized/rusting (ie, Fe2+), but wikipedia lists hematite as being Fe(III)2O3, ie, not oxidized/rusting and therefore gray. Does the red variety only exist when the hematite crystal comes into contact with oxygen to make it rust? Or am I completely off track on this? | [
"First off, you have it backwards: ferric iron (Fe3+) is ",
" oxidized than ferrous iron (Fe2+). Oxidation is the ",
" of electrons, so when ferrous iron is oxidized to ferric, its oxidation state goes from +2 to +3: ",
"+2 - (-1) = +3 ",
"Likewise, when ferric iron is ",
" (gains electrons), it fo... | [
"Thanks for the answer and the clarification of oxidation/reduction."
] | [
"While I'm not entirely sure of the exact reason for haemetite (I'm guessing it's different crystal structure), many materials have two or more structures that are stable under normal conditions. The first examples I can think of are carbon, phosphorus and sulphur. Carbon has graphite and diamond (and others), phos... |
[
"If the gravitational attraction between the sun and the moon is greater than between the earth and the moon, why isn't the moon in independent orbit around the sun?"
] | [
false
] | The Sun's gravitational pull on the Moon is over twice as great as the Earth's pull on the Moon I think the answer has something to do with , but my physics intuition on centripetal acceleration isn't working for me right now.. | [
"The moon ",
" orbiting the sun, with the Earth, which is experiencing the ",
" acceleration (more or less) as the moon, so they move together.",
"If the Earth weren't here, the moon would look like it was orbiting the sun, just wobbling a lot.",
"EDIT: Remember, ",
" the Earth and the moon are falling to... | [
"You should be looking at the acceleration, not the force.",
"The force is less on the moon, but the moon also has less inertia. These two factors neatly balance out to give the same acceleration. This is for the exact same reason that two objects of different weights fall to earth at the same rate.",
"As Keple... | [
"The moon's orbit around the sun is everywhere-convex, so you could argue that the moon is orbiting independently around the sun. The slightly lesser pull between the earth and the moon keep the two together."
] |
[
"I know our cells use ATP and GTP for hydrolysis and other energy needs. Why don't cells use cytidine triphosphate or thiamine triphosphate as much as the other two classic triphosphate nucleotides?"
] | [
false
] | null | [
"Mainly because there was never any selecting pressure to do so. Evoluton of bioenergetic sustems is a very complex process; ATP:ADP concentration have to be kept far far far far away from chemicsl equilibrium otherwise delta G would be 0 and you could not extract energy."
] | [
"Thank you for your answer! If you don't mind me asking a follow up question; do our cells maintain ATP concentrations beyond random diffusion? Do our cells have a gradient in certain regions of the cell? If so how do they accomplish this?"
] | [
"Yes they do; they can change the local concentrations of ATP when it is required. For instance, in filopodia or during developmental growth cones, ATP is required at these edges of the cell for cytoskeletal dynamics that are occurring. That's just one example, but even in an apparently \"non-active\" cell there is... |
[
"How do we know the interaction rate of neutrinos? (Light-year of lead, etc)"
] | [
false
] | An oft-cited scientific fact is that a solid block of lead one light-year in length would only stop half the neutrinos that are to pass through it. How do we know this? We can only detect particles by interacting with them, right? So how do we know if the particles are there or not if only 50% of them interact? How ... | [
"How do we know this? We can only detect particles by interacting with them, right? ",
"Sort of; you can also detect missing particles from missing energy/momentum using known conservation laws. You know beta decay (neutron decays to proton and electron and a neutrino) right? If you try to exclude the neutrino,... | [
"So how is this rectified with the recent OPERA experiment showing that neutrinos move faster than the speed of light?",
"By saying the OPERA result is probably wrong. "
] | [
"You can calculate the probability amplitude of a neutrino interacting with another particle or material (based on its density) via the weak force (since neutrinos have no charge and don't interact with the strong force). That is all. It's a probability, with a degree of certainty one can say that there will be 50%... |
[
"Why does ethyl alcohol evaporate out of your beer/wine/booze so slowly?"
] | [
false
] | [deleted] | [
"Alcohol and water aren't an ideal solution, but the general principle of ",
"Raoult's Law",
" applies to your question. Here's a two-part explanation. Skip the first part if you already understand vapor pressure.",
"A liquid will evaporate until enough of it is in the vapor that the vapor and liquid are in e... | [
"Ethanol will evaporate more quickly than water, but in an ethanol-water solution, the ethanol and water will interact and this will slow it's evaporation compared to pure ethanol."
] | [
"Yes. Below answer is related to why.",
"Edit: This is why 160 proof liquor smells like liquor. What is happening is that the azeotrope discussed below can be broken down thermally(randomly), and the ethanol molecule can go into the gas phase if it has enough energy. The more ethanol molecules you have relative t... |
[
"Is Sugar in the Raw really healthier than normal sugar?"
] | [
false
] | I never understood the difference between the two. I know sugar in the raw "contains more natural minerals" that are removed when it is refined to white sugar. | [
"\"contains more natural minerals\"",
"The term \"natural\" is a bit loaded. The connotation implies that it's more wholesome or good for you (because nature is always good right?), but the truth is most minerals are naturally occurring and that has no bearing on whether they're good for you or not.",
"From wha... | [
"\"natural\" is beyond loaded, it's a false distinction."
] | [
"To speak to that fact:",
"Mercury is mostly inert (unless refined) but still all natural.",
"Lava is all natural.",
"Horse hair is all natural.",
"Oleander is all natural.",
"None of these are good for you and are at best, unpalatable.",
"EDIT: Snake venom is all natural."
] |
[
"What would the perception of time be like to a person who could live forever?"
] | [
false
] | null | [
"This is a hypothetical that, I feel, reaches beyond the scope of ",
"r/askscience",
". Too much speculation is needed. ",
"/r/transhuman",
" might be a better place to ask."
] | [
"I don't feel it's too hypothetical. I'm sure at some point in the future, thanks to medical breakthroughs, certain people will be able to live to be 150 if not 200 years old. "
] | [
"I agree that average life expectancy is tending to increase and that long life times are quite likely in the near-ish future. However, the issue of how those lives will be experienced is another matter.",
"However, I had taken on the idea of 'immortal' lives and used that as the basis for suggesting it was specu... |
[
"Why are bubbles always spherical when blown?"
] | [
false
] | Whenever bubbles are blown, they appear to always be in a spherical shape of different sizes. Why not cubes or other shapes? | [
"There are primarily two forces to consider: pressure and surface tension. There is an outward force due to the difference in pressure between the inside and outside of the bubble, and there is an inward force due to surface tension.",
"The force due to the pressure gradient is trying to increase the volume but t... | [
"Similar processes are why planets are spherical, free floating cells are spherical, and why oil in water is spherical!"
] | [
"You can see the push and pull of this if you blow a really big bubble. The film of soap and water doesn't start out perfectly even in thickness and so it doesn't e wet a perfectly even force against the air pressure. This makes the bubble oddly shaped and it will become more and more spherical until it gets there,... |
[
"Can we, given today's technological llmitations, passively refridgerate/cool something indefinitely? If not, how long can we make it last?"
] | [
false
] | I think I'm phrasing it correctly, but if not, what I mean is: Could we currently create a powerless cooler or thermos that would keep something cold indefinitely? | [
"Cold is a relative term. For instance, we can passively cool buildings. Westinghouse claims their new AP1000 nuclear reactor can passively cool the core for 72 hours; after which is just need a top up. ",
"If you can put something in a sufficient cold environment, this would help (maybe space?).",
"All-in-all,... | [
"This was a much more informative answer than I expected, thank you!"
] | [
"From your description, you seem to be asking if we can create a perfect insulator, a material that will not transfer heat between an object and its surroundings.",
"The answer to that is no. There will always be some heat transfer."
] |
[
"Are humans the only species with (nearly/seemingly) unrestricted hair growth, in terms of length?"
] | [
false
] | It seems like most animals either have fur or short hair. Hair seems pretty uncommon as it is, much less the ability to grow super long hair. Since other animals don't seem to have the ability to cut their hair, I would assume it would be a noticeable trait. Maybe not? | [
"All hairs grow in cycles typically described in 3 stages; Anagen, Catagen and Telogen.",
"The Anagen phase is the growth phase, the length a hair grows to is determined by the length of the anagen phase for that particular type of hair follicle. ",
"In the Catagen phase the follicle detaches from the hair root... | [
"Horses can have pretty impressive manes and tails. ",
"http://arabianhorselovers.webs.com/andalucion.jpg",
" ",
"http://www.horsenation.com/wp-content/uploads/2013/04/guiness-record-longest-horse-tail.jpg",
" ",
"http://www.horsenation.com/wp-content/uploads/2013/04/longest-horse-mane-tail.jpg",
" ",
... | [
"Interesting that all of the examples of animals with extremely long hair have been subject to artificial selection. Horses are a really cool example because ",
"wild horses",
" have short manes whereas ",
"feral horses",
" grow these crazy dreadlocks that usually end up getting ripped out after a year or s... |
[
"[ASTRONOMY] Did galaxies form at roughly the same time throughout the observable universe?"
] | [
false
] | The farthest observed galaxy is 13.2 billion light years away. This puts it's formation at around 480 million years after the big bang. The Milky Way (to my understanding) is estimated to be 13.2 - 13.4 billion years old. Does this mean that the energy that coelesced into the matter that formed the galaxies was spread ... | [
"Great question! The universe is isotropic, meaning that it looks relatively the same no matter where you look in the sky. This means that on large scales, there will not be a particular area of space that has older galaxies than another area of space. So, many of the oldest galaxies are spread out.",
"The Big Ba... | [
"galaxies are where they are because of dark matter. dark matter is the primary source of gravity, so any normal matter clumps according to the dark matter distribution."
] | [
"Wow thanks for the great answer. It finally \"clicked!\""
] |
[
"If a made-up food had the texture, smell and look of a normal strawberry, but had the taste of a banana, would my mind blend the flavors together to make it seem like strawberry-banana?"
] | [
false
] | null | [
"Yes, but only because of the smell. You can only taste a few basic tastes (sweet, sour, bitter, salty and that mythical umami) with your tongue, the complexities of food come from smell. Classic example? Food tastes all kinds of dull when you're stuffed up.",
"Try this: take a bite of strawberry and hold a stick... | [
"There's noting mythical about umami"
] | [
"A \"savoury\" flavour. (soy sauce as an example.)\nIt is the flavour of MSG."
] |
[
"What was the first commercial device to use strong encryption?"
] | [
false
] | Was it the AT&T TSD 3600? And is that why the NSA was so panicky in implementing the clipper chip into this device? Before this device were all commercial telecommunications open to being wire tapped by law enforcement agencies? Sorry for all the questions, just trying to understand. Thanks in advance. | [
"How do you define strong encryption?",
"The enigma machine used pretty damn strong encryption in the 1940's - although it was probably not what you would consider a \"commercial\" machine - even though 40000 were made."
] | [
"IIRC early basic versions of the enigma were sold commercially. I’m on mobile but I’ll try and find a link."
] | [
"There were other products for secure telephone before, but the TSD 3600 was the first widely available one. There were other commercial encryption products before, particularly the Enigma, which was originally designed for the commercial market to secure telegrams. ",
"Describing the NSA as \"panicky\" is over... |
[
"If a drug or vaccine fails an animal trial, how can scientists be certain that it will similarly fail a human trial, given the different physiologies between species?"
] | [
false
] | Scientists often use mice to test for drugs and vaccines, but we know that not all successes in rodent trials translate to successes in human trials due to the different physiology between species. But what about the reverse? Could there be drugs that might have worked in humans but weren’t successful in rodent trials ... | [
"This is a great question. The answer is not trivial, but essentially researchers typically know how conserved a drug target is among different species and use this information to predict whether the same outcomes would be likely to be observed in rodents, and primates/ humans. ",
"The use of computational biolog... | [
"Could there be drugs that might have worked in humans but weren’t successful in rodent trials and were therefore never pursued further?",
"Yes, but the research path is also usually not totally linear. To get to a drug which can be used in a human there is frequently a lot of optimization, or would otherwise be ... | [
"... Also, often when a drug gets all the way to animal trials and then fails, it will be because the animals die from the drug, get really sick, develop cancer etc. Surely, there could be species specific differences so that this wouldn't be the case in humans - but, ethically, you can't really move on to human tr... |
[
"Can we find complementary colors for non-visible wavelengths of light?"
] | [
false
] | null | [
"I love your question. The answer is probably the one cited by the Wikipedia quote on \"Primary colors\":",
"Primary colors are not a fundamental property of light but are often related to the physiological response of the eye to light. Fundamentally, light is a continuous spectrum of the wavelengths that can be ... | [
"This is only peripherally related, but there is a great ",
"podcast episode",
" of NPR's Radiolab that explores what it would be like to actually see a much broader spectrum of colors than humans are capable of seeing (being able to see what is currently outside the visible spectrum). Some animals see a much w... | [
"Thanks! I thought that this might be true. If there ",
" primary colors for non-visible wavelengths of light, I assumed it would be because of a relation between complementary colors and their respective wavelengths. In the absence of said relationship, your response answer my question nicely. Again, thanks!"
] |
[
"A serious poop question."
] | [
false
] | null | [
"Your intestines will continue to absorb water from the fecal matter, making it denser and harder to pass. If you hold it long enough you may get ",
"impacted",
", and require medical help.",
"Unless you suffer from chronic constipation, or you've ingested a lot of something likely to ",
" constipation, I w... | [
"Eh. Unless you've got diarrhea, the water content of your poop isn't really significant. Better to get rid of it while you can, rather than add severe constipation on to the rest of your survival woes."
] | [
"Eh. Unless you've got diarrhea, the water content of your poop isn't really significant. Better to get rid of it while you can, rather than add severe constipation on to the rest of your survival woes."
] |
[
"Is each neutron star a new \"element\" composed of a huge number of protons/neutrons?"
] | [
false
] | I am familiar with the element on the periodic table, and they go up to a certain atomic weight and then they are too big and fall apart (sorry for not knowing the right terminology for that). But I picture that black holes must have enough force to collapse the nuclei of neighboring molecules together to form new elem... | [
"http://en.wikipedia.org/wiki/Neutronium"
] | [
"False, neutron stars do have protons, but it's certainly not an even number, there are very few protons and a high number of neutrons, which most models predict.",
"Though we don't know for certain, we don't know much about neutron stars to begin with, other then what models suggest. Remember, we call them neutr... | [
"Things become black holes when the Schwartzschild radius is bigger than the radius of the object."
] |
[
"Does temperature have any effect on Kinetic or potential energy?"
] | [
false
] | [deleted] | [
"Thermal energy is a different category from kinetic or potential energy. It is possible to trade one for the other (for instance, when you stop a ball, some of the kinetic energy becomes thermal energy due to friction).",
"Generally though, thermal is more distinct from kinetic + potential energy for reasons of ... | [
"If the ball exchanges heat with other objects (e.g. your 'templates'), then the ",
"internal energy",
" of the ball will change in proportion to the increase or decrease in its own temperature. The change in the ball's internal energy from the heat exchange with those hot or cold objects will not affect its me... | [
"To a first approximation and for most temperatures, the temperature will make no effect. However, generally when gas is heated or cooled it expands/contracts, which makes it less/more dense (pV ~ NkT for medium-high gas temperatures), and therefore there is less/more resistance to an object traveling through it. ... |
[
"If every pore in your skin was completely cleaned out would your skin have any noticeable change? How much stuff would be taken out?"
] | [
false
] | null | [
"Your pores routinely produce protective oils and secretions which protect your skin and allow helpful microbes to live on your skin surface which reduce the chances of harmful micro organisms from taking residence. The result of the cleaning would only be very temporary as your body is always producing secretions.... | [
"It's not up to the mods to discredit bad science; that's your job if you know it. Simply calling someone out without offering a counter view is quite useless."
] | [
"It's not up to the mods to discredit bad science; that's your job if you know it. Simply calling someone out without offering a counter view is quite useless."
] |
[
"If you fill a perfectly sealed diamond box with water and froze it would it break?"
] | [
false
] | If you fully filled a diamond box with water, then froze it what would happen? Would the water not turn to ice? Would the box break? EDIT: Im saying as if hypothetically the water just appeared inside of a hollow diamond. | [
"You're constraining the volume of the system. If the diamond box (note - diamond is actually pretty brittle) didn't break, then you'd be balancing the temperature of the water against the increasing pressure due to the water/ice phase change. As the water starts to freeze, then the pressure increases, making it ... | [
"Depends on the rate of cooling because ice has several different crystalline structures and can become amorphous. Also how many atmospheres of pressure could build inside the diamond before it breaks as some types of crystalline structures have a higher density than normal ice."
] | [
"Interesting answer about the pressure exerted by expanding ice ",
"here",
":",
"If you completely freeze the ice it expands 9%. If you try to SQUEEZE the ice back down to the original size, you would need to push with a pressure of about 790 megapascals of force. (8,800,000,000*0.09) That is about 114,000 po... |
[
"If there were no day/night and only the same light level outside, how long would humans be awake for and sleep?"
] | [
false
] | I remember something like this was asked before, but could't find the post. | [
"/u/whatthefat",
" gave a lot of good answers to sleep related questions in the past",
"see, for example:",
"http://www.reddit.com/r/askscience/comments/1amf7t/is_sleep_only_an_evolutionary_byproduct_of_the/c8z7phx",
"http://www.reddit.com/r/askscience/comments/1day1r/is_our_circadian_rythm_fixed_is_it_poss... | [
"Doesn't blue-ish light inhibit melatonin production? (ie. Don't you need light to stop making melatonin during the day?) I'd assume that if you only ever had blue light you'd have sleep issues..."
] | [
"Doesn't blue-ish light inhibit melatonin production? (ie. Don't you need light to stop making melatonin during the day?) I'd assume that if you only ever had blue light you'd have sleep issues..."
] |
[
"How can pain relievers like ibuprofen sometimes eliminate pain when all they really address is the sensitivity of nociceptors after tissue damage, not the nociceptive response to noxious stimuli in the first place?"
] | [
false
] | It seems like this would just keep the pain from getting worse by inhibiting the production of prostaglandins and keeping the nociceptive threshold normal, not relieve the pain present at the normal threshold being caused by the underlying stimulus. Is it because ibuprofen also inhibits the production of prostaglandin... | [
"One of the prostaglandins produced by COX is PGE2. This prostaglandin doesn’t just cause pain, it ",
" the skin to pain. By blocking the production of this prostaglandin, NSAIDs raise the threshold for pain, effectively removing it. "
] | [
"It doesn't raise the threshold ",
" much. Better off just taking some opioids and numbing yourself up entirely"
] | [
"It doesn't raise the threshold ",
" much. Better off just taking some opioids and numbing yourself up entirely"
] |
[
"Why are some viruses more difficult to make vaccines for?"
] | [
false
] | [deleted] | [
"It doesn't work for all viruses because all viruses are unique. ",
"HIV for example undergoes very rapid mutations and also infects CD4+ cells. This means for HIV you could have a vaccine that eliminates one subset of HIV particles but allows the thousands of other subsets to preset. Additionally because it infe... | [
"A very simple way of conceptualizing what the heck a vaccine is is in this way:",
"Picture a car. On its surface it has different contours (windshield wiper, bumper, etc.). Now, imagine a big human cell that sort of attaches itself to, say, the bumper. It's really good at recognizing the bumper, and so it goes a... | [
"I like the other answer provided, but I do want to add on that you (OP) have a bit of a misconception about how vaccines work.",
"Vaccines do not technically introduce antibodies to your system. Vaccines contain one of three things: attenuated (weakened) live pathogens, dead pathogens, or pieces of pathogens. In... |
[
"Is the erectile tissue in a penis found anywhere else (bodywise) in anything biological?"
] | [
false
] | Basically, is there a species out there that has erectile tissue somewhere in/on their body other than their penis? Or is it unique to the penis? | [
"Nasal turbinates. The maze of your sinuses is regulated by erectile structures that can block your nasal passages. They are responsible for a 'stuffy nose.'",
"Precisely how related the structures are is up for discussion. Nosebleeds and 'honeymoon rhinitis' are an uncommon effect of Viagra, which suggests some ... | [
"The most notable example is the female clitoris which both contains erectile tissue and displays tumescence (erection) with arousal. This is understandable when your remember that the ",
"clitoris and the penis are homologous",
" and have a common embryologic origin.",
"Side note: The clitoris can even exper... | [
"does that mean that some decongestants could cause temporary impotence."
] |
[
"Can we replicate the process of making fossil fuels?"
] | [
false
] | Had a question asked by a fourth grader that got me thinking. I’m not concerned if it’s viable, economical, or practical. But theoretically could we replicate conditions over a period of time to create crude oil? What would be the rough requirements and timeframe to make this happen? | [
"Yes, and it's been done for quite a while, usually in the context of trying to understand the details of and controls on natural petroleum formation. There are hundreds of papers published on these types of experiments looking at different aspects of the system, for example here is one by ",
"Epistalie & Tissot,... | [
"Finally, as you suspect, these types of processes are not efficient or useful in a producing fuel sense (i.e., most of these experiments are probably putting more energy in than they would get out if they used this petroleum for fuel and are operating on very small quantities), but have been incredibly important f... | [
"Do you know what the actual efficiency of those processes is in theory or practice though? Seems like you'd still run into the issue the previous poster mentioned.",
"Uranium has a energy density 1 000 000 times that of fossil fuels. Even if the process was 0.1% efficient you would be able to carry at least a 10... |
[
"Why does facial hair grow at different rates based where it is on the face?"
] | [
false
] | null | [
"Facial hair growth is dependent on androgen receptors specifically for dihydrotestosterone.",
"http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2265.1993.tb02420.x/abstract",
"This study shows beard hair follicles are largely comprised of dihydrotestosterone being that it is necessary for said growth. ",
"h... | [
"So this would explain why I've heard that people taking anabolics, even women have increased facial hair. Now is this caused only by increased dihydrotestosterone levels in the blood, or do some of the supplements increase the androgen receptor activity? "
] | [
"I think the real question here is why does hair grow at uneven rates on any part of your body? I'm sure that Facial hair, body hair, and head hair are all plagued by this."
] |
[
"Members of the cat, dog, bear genus are common apex predators. What can you predict about a given environment by knowing the apex predator?"
] | [
false
] | null | [
"I'm still a student, but let me give some small insight on this. ",
"Apex predators can be keystone predators - meaning they exert an unequal influence on the trophic system. If they disappear, the whole system is severely damaged. But that's a different matter (but I recommend a ",
"book!",
")",
"Let's co... | [
"By knowing just the species of apex predator involved? Not too much by itself. Many ecosystems have historically had (for example) all three types in your example, and as whole clades these are very wide ranging groups over broad habitat and prey types. Maybe you'd learn something obvious if you knew them to sp... | [
"Truth is not much. You must first consider historical ranges and extinct species, because if you just looked at where apex predators are now the only thing it would likely correlate to is low human population density. Looking at this you would find large cats, pack-hunting canids, and largely omnivorous bears on ... |
[
"What is it about grapefruit that interacts with some medications?"
] | [
false
] | null | [
"Grapefruits contain organic chemical compounds called furanocoumarins. these compounds affect the enzymes used by the body to metabolise many drugs in the body. Cytochrome p450 is a common enzyme used by the body to 'break-down' drugs and when preoccupied by the chemicals in grapefruit juice allow for drugs ingest... | [
"Seldane, a formerly popular allergy drug, would in extreme cases produce a toxic compound that killed a few people "
] | [
"Yes, really. ",
"Ritonavir",
" is an HIV protease inhibitor that can be used to treat HIV on its own, but has severe side effects in therapeutic doses. However, it is an inhibitor of CYP450, just like grapefruit juice. It is now given in lower amounts along with other HIV drugs to boost their effects by blocki... |
[
"Have there ever been any cryptozoological creatures that were later found to be real in the past couple centuries? Would the Panda count?"
] | [
false
] | As I understand it, Western civilization had never seen or come in contact with pandas until the early 20th century. There were cases of merchants selling panda fur in the 19th century, but I can't seem to find any information as to whether or not westerners usually assumed the animal to be real. Was the existence of ... | [
"The answer is a big \"it depends\".",
"On the one hand, you have tales of sea monsters, hairy wild men, and dragons from many cultures. Does the discovery of giant squid and whales, great apes, and dinosaur bone validate these tales, or is it mere coincidence.",
"On the other hand, you have things like the Ki... | [
"The platypus was for a couple years considered to be a hoax when the first pelts were sent back in 1798. They actually cut open the bill to make sure there were no stitches holding the insane looking animal together"
] | [
"The Mountain Gorilla and ",
"Okapi",
" are both considered to be former cryptozoological creatures as I understand it"
] |
[
"What became of the star that supernova'd prior to the formation of Sol - is there any way we could locate its remnant?"
] | [
false
] | null | [
"Supernova remnants expand quickly - at thousands of km/s - and start to dissolve into the galactic background of gas after tens of thousands of years. This is quite quick, and much much younger than the age of the Sun, which is 5 billion years old. The supernova remnant is long gone, and we've orbited the Milky Wa... | [
"Lots of supernovae, but the heavy elements get mixed into the galaxy's \"interstellar medium\" as a whole, and a molecular cloud condenses from that medium. It comes out the same as \"what tree produced the oxygen I'm breathing?\""
] | [
"Wow, thanks for answer, but follow up question:",
"So I'm envisioning a molecular cloud somewhat akin to eagle nebula - dense, and high metallicity - where did all that metallicity come from, if not ",
", or perhaps several or many, prior supernovas?"
] |
[
"How does combustion power a rocket?"
] | [
false
] | null | [
"For the type of rocket that uses combustion at all, the combustion is what ",
" the exhaust gas that is being pushed out the back to make the thrust. There ",
" gas to be \"lit on fire\" until you ",
" that exhaust gas by burning the rocket's fuel.",
"The rocket has some burnable fuel which will be a solid... | [
"What is a propellor doing on the front of a plane if not acting like a compressor, pushing air backwards? Don't even need a nozzle or tank, that just adds complexity and extra steps (though, that's kinda what a jet engine is, I suppose...)"
] | [
"No, the temperature itself helps as well. If a gas is hotter, the gas molecules themselves will be moving faster, which means that after expanding through the same pressure ratio, you get a faster-moving exhaust flow which gives a higher thrust.",
"For example, if you have nitrogen gas at 20 atm of pressure and ... |
[
"Current vaccines are essentially a weakened virus/microbe. Is it possible to contaminate an other person with this weakened vaccine?"
] | [
false
] | null | [
"Yes, it is, but it depends both on the nature of vaccine and the immune system status of the person who is infected. Some vaccines are completely dead and are incapable of infecting anyone (there are exceptions to this but it would be an incredibly small possibility) and then there are live attenuated vaccines whi... | [
"Not all current vaccines are weakened pathogens, although some are. The FluMist, oral rotavirus, and MMR vaccines are all what are called \"attenuated\" vaccines, which replicate in the host and induce strong immunity. In contrast, the flu shot, DTaP, pneumococcus are examples of \"inactivated\" vaccines, where ... | [
"In the case of the live attenuated virus, they are infected with the same pathogen as was in the vaccine, it's weaker, but if the immune system isn't strong enough to eliminate the virus, it really is a moot point it was weakened in the first place.",
"As a side note, all vaccines could be said to \"weaken\" the... |
[
"When does one use \"data\" as singular or plural?"
] | [
false
] | null | [
"Singular in this case. ",
"More reading"
] | [
"Data is in fact plural. The singular of data is datum. However, you almost never concern yourself with an individual datum, so data tends to be used as both the singular and plural. In your example, the strictly correct sentence would be",
"\"The data in this study were ....\"",
"but no one is going to care... | [
"In that case it would be singular. You are defining the data as a single set belonging to the study. You should use \"was.\"",
"If you were referencing multiple sets of data which you were making a distinction between you would use were. Ex. \"The data from trials 1 and 2 were...\""
] |
[
"Does your brain absorb information while asleep?"
] | [
false
] | Does your brain absorb information while asleep Through listening does your brain feed that information into the subconscious? Has anyone tried this? Playing a lecture or a podcast but you fall asleep | [
"There are studies that have shown that reinforcing previously learned information is probably a real thing, but TMK actual sleep-",
", as in \"acquiring new information,\" is still much in doubt.",
"Your brain for sure processes information while you sleep, though, and many people (including me) find it helps ... | [
"www.livescience.com/amp/64920-how-learn-during-sleep.html",
"Not the paper in question that I read. But I dunno, take it for what it is."
] | [
"www.livescience.com/amp/64920-how-learn-during-sleep.html",
"Not the paper in question that I read. But I dunno, take it for what it is."
] |
[
"Are the blackholes in center of galaxies formed by super gigantic stars?"
] | [
false
] | I understand that if a star is huge in mass it can form a blackhole and that at the center of the galaxy there is a blackhole. Does that mean that, for example at the center of the Milky Way, there was once a gigantic star that has collapsed? Or is it more likely that it was a blackhole that has simply gotten bigger ov... | [
"The black hole in the galactic centre (Sg A*) is far too massive to have formed from a single star (it is of the order of a few million solar masses, stars are rarely found above a hundred solar masses due to stability). Thus, it must have grown over time from coalescing black holes plus accreted matter.",
"This... | [
"That is actually the astronomers' version of the chicken or the egg. Did the galaxy form first and the mass in the center collapsed to form a black hole, or did the black hole form first and the matter organized around it to form the galaxy. It is possible in the first moments after the big bang, there were some... | [
"Yeah, that was my own thought. I was thinking about how a nucleas becomes unstable once too big and wonder whether or not that'd apply to a star to some extent(i.e too big for it's own good). Let me to wonder whether or not the black hole in center of galaxy was formed from a huge star or just a normal sized one t... |
[
"When we talk to ourselves or read inside our heads, how is it possible that we can 'hear' what we are saying/reading?"
] | [
false
] | [deleted] | [
"During internal monologues the parts of your brain associated with speech is actually active and sending information to the areas associated with the understanding and reception of sounds. It is theorised that there is a corollary discharge of neurons during this process that tells the brain this is internally gen... | [
"That is a thing? What is it called? I'm having a hard time comprehending how you retain what you read, or how think about what you are going to write/say."
] | [
"No because the communication is from the area that creates speech to the area that receives and understands speech. When actually talking there will be signalling to the primary motor cortex to make the movements to produce speech as well. Therefore the lack of internal labelling (corollary discharge) causes the i... |
[
"What would the practical applications be if superconductors were to be discovered?"
] | [
false
] | null | [
"Superconductors have been discovered, do you mean ",
" superconductors?"
] | [
"There is nothing in the question which implies it. But anyway, they could have practical applications like lossless power transmission, strong magnetic fields without the need for expensive cooling, and very good magnetic shielding."
] | [
"Yes, that's kinda implied. "
] |
[
"If a pregnant woman gets sick with a cold or an immunization like a flu shot does the fetus develop antibodies/immunity?"
] | [
false
] | null | [
"No.The mother will produce antibodies and pass them on to the fetus."
] | [
"It is passed on through the placenta.\nAll of the mothers immunity is passed on during the last three months of pregnancy and when the baby is born immunity starts to decrease after the first few weeks.Breast milk also contains antibodies so the baby is protected for as long as the mother breast feeds.After that i... | [
"Thank you, do you know how it is passed on? Like is all the mothers immunity passed or just immunity that is currently being used. Like if the mother is fighting an active infection is only that immunity passed or does all immunity pass?",
"I guess I am curious in general about how immunity passes from one entit... |
[
"Carbon Fiber vs. Carbon Nano-tubes"
] | [
false
] | I was wondering about the difference between carbon fibers and carbon nano-tubes, both in structure and utility. Sadly Google didn't provide any help and the Wikipedia article was to dense for me to understand. Hopefully you guys can help. | [
"What is commonly referred to as \"carbon fiber\" is usually in reality a ",
"carbon-fiber-reinforced polymer",
", which is basically a composite material consisting of sheets of ",
"carbon fibers",
" and some sort of epoxy bonding them together.",
"Actual carbon fiber sheets are essentially \"blankets\" ... | [
"To expand on this, the most common use of nanotubes today is the reinforcement of the tensile strength of polymers, not as a pure construction material themselves. The nanotubes function similarly to iron rebar in concrete."
] | [
"Just to try and highlight the differences in structure: ",
"The main differences in structure can be boiled down to order vs. disorder.\nCarbon nano-tubes have a very defined/ordered structure-its a rolled up sheet of carbon (in a hexagonal pattern with sp2 bonding) forming a closed tube- closed along its axis,... |
[
"What are career prospects for an Environmental Science major like?"
] | [
false
] | I've started studying environmental science at a large university. I haven't decided on any specialization. What are career prospects like for someone with a BS in Environmental Science? I'd rather do work for business than in academia. I've heard a lot about so-called "green jobs" but is it just a hype bubble read... | [
"I've two friends who focused on Geographic Information Systems within their Environmental Science degrees. One is now starting a part time gig with a radio station and the other is currently unemployed. I think this might, perhaps, speak more about the prospects within GIS than Environmental Science."
] | [
"Many of my friends that graduated with a B.S. in Environmental Science are working at some capacity in the government, either on a local, state or national level. There are surely private sector jobs, but I am unfamiliar with their prevalence."
] | [
"I was told by a professor in my college that the head of our biosystems engineering department was contacted by a group from Australia and they are looking for 5,000 recruits to be put on a starting wage of 60,000 (I'm assuming Euro) for ",
"Master graduates in my field",
". "
] |
[
"When is an approaching object's pitch highest?(Doppler effect)"
] | [
false
] | [deleted] | [
"As others have said, the apparent pitch is only affected by the relative velocity between the object and observer. The faster the object moves with respect to the medium (air), the more compressed the sound waves in front of it and the more spread out behind it. If the observer lies stationary directly on the obje... | [
"Doppler effect is from two objects' relative velocity and doesn't have anything to do with distance if the two objects are moving directly toward or away from each other. Assuming there isn't acceleration involved, the pitch would be the same (frequency + relative velocity) during the entire approach, would be th... | [
"Yes. Without velocity, there would be no apparent shift in the frequency. If you have a device that can measure the frequency as it runs along its path from approach to CPA and past, you can use those frequency shits to determine the velocity of the object. "
] |
[
"\"Hot topic\" diseases get a lot of research attention (and money). But what about cosmetic diseases like seborrheic dermatitis? Have there been any recent revelations in determining its cause, or innovations in treating this annoying and unsightly (but harmless) disease?"
] | [
false
] | null | [
"The thing with medicine is studying one thing usually has far reaching results for many diseases (even the non threatening but annoying ones)",
"Chronic conditions like that tend to be rooted in Immune system disorders where the body attacks itself or is over sensitive. Now it may not be the center of attention ... | [
"Here",
" is a review article from 2009 going over the latest research in that area."
] | [
"latest research... 3 years ago :("
] |
[
"Do we know why the speed of light is what it is, or just that it must be what it is?"
] | [
false
] | I spent the day trying to find a nice answer to the why, which lead me on a nice journey into zero-point energy and the possibility that quantum vacuum might be the origin of the speed of light, but didn't really get a nice answer. | [
"The only meaningful question is \"why is the speed of light finite?\" Well, it just is. ",
"Obviously, there are two possibilities: particles can have arbitrarily large speeds or they can't. If you insist that physical laws cannot violate causality and physical laws take the same form in all inertial frames, the... | [
"It just is.",
"That's the unsatisfying answer I was finding."
] | [
"This question doesn't really make sense. What could you possibly mean by everything happening at once?",
"Also asking what would happen if the speed of light were infinite is much too speculative a question to offer much of a meaningful answer. "
] |
[
"How do painkillers work?"
] | [
false
] | null | [
"It depends what kind of painkiller you mean.",
"NSAIDs are the mild analgesics that you'd take for minor-to moderate pain (like aspirin or ibuprofen). These drugs work by inhibiting COX-2 enzymes, which convert arachidonic acid to small molecules called prostaglandins. When we feel pain, it can be an acute-refle... | [
"Oh i get it now, thank you."
] | [
"Oh i get it now, thank you."
] |
[
"Last summer, there was big news about a robot set to explore some tunnels of the Great Pyramid. Googling gives me nothing but articles about the exploration, not the results. Anyone in the know?"
] | [
false
] | null | [
"The event you speak of might be the one that took place in 2002 and was a tremendous publicy-stunt by ",
"Zafi Hawass",
", the egyptian minister for antiquities. Kind of a narcissist. Video was transmitted world-wide, allegedly live.",
"See also ",
"Upuaut-project",
" ... this engineer did initially deve... | [
"This is the closest my googling can bring me - \n",
"http://www.drhawass.com/blog/djedi-team-robot",
"This is the official page of the team that did it.",
"Edit - ",
"http://www.drhawass.com/events/mystery-hidden-doors-inside-great-pyramid-0",
"There is a National Geographic video of this."
] | [
"Related - ",
"http://www.youtube.com/watch?v=PnNO9S_W1V8",
"After they drilled through the second door they found...",
"another door"
] |
[
"How can pure substances have multiple triple points?"
] | [
false
] | So a triple point is defined as "the temperature and pressure at which three phases (gas, liquid, and solid) of that substance may coexist in thermodynamic equilibrium" but my textbook also says "a pure substance can have a number of triple point, but only one triple point has a solid, liquid and vapor equilibrium. If ... | [
"Your assumption is correct, there are multiple solid phases. So the solid-liquid-gas triple point is the unique point where the gas and liquid phases are at equilibrium with ",
" solid phase out of the multiple. The other triple points involve multiple solid phases."
] | [
"Multiple solid phases are obviously the most common, but multiple liquid phases is possible as well, e.g. in helium."
] | [
"Regular liquid and superfluid."
] |
[
"Can music affect an animal's mood and/or behavior?"
] | [
false
] | null | [
"This is true. I think the question would be better asked as \"Does ",
" music affect another species mood/behaviour?\""
] | [
"Parrots would give that question a yes.",
"http://news.nationalgeographic.com/news/2009/04/090430-birds-dance-rhythm.html",
"http://www.youtube.com/results?search_query=parrots+dancing+to+music&oq=parrots+dancing+to+music&gs_l=youtube.1.0.0.4317.10613.0.13437.24.19.0.5.5.0.222.2875.1j16j2.19.0...0.0...1ac.1.Sy... | [
"Does it affect your mood and/or behavior? It sure does mine and I'm pretty confident that I am an animal. Unless you are a robot I'm pretty sure you are too. So yes, music clearly affects animal behavior and mood."
] |
[
"Antineutrinos or neutrinos?"
] | [
false
] | Are there more neutrinos or antineutrinos in the universe, as far as we know? | [
"On average throughout the universe the neutrino density is dominated by the cosmic neutrino background. I think this should have equal numbers of neutrinos/antineutrinos.",
"Here on Earth however the neutrino density is dominated by solar neutrinos, which are almost entirely matter neutrinos."
] | [
"I think this should have equal numbers of neutrinos/antineutrinos.",
"I would be very careful with this statement. There are bounds on the chemical potential of the cosmic neutrino background, but they are pretty weak. The strongest bound comes from BBN and states neutrino asymmetry can be as big as eta_nu ~0.0... | [
"So if there are more neutrinos than antineutrinos in the universe, is that due to \"nonthermal production\" of neutrinos in the early universe? What does that mean, and might there be other causes of the possible asymmetry? ",
"Also, are only neutrinos produced in core collapse supernovae, or antineutrinos too?"... |
[
"Is alchemy theoretically possible, with science not with magic?"
] | [
false
] | If we had the technology to manipulate atoms, could gold be created from something else like Mercury? I was thinking about alchemy and was curious as to whether or not a Mercury atom would be turned into a gold and a hydrogen atom if we could remove a proton. Additionally, is there any discussion on whether or not this... | [
"This is possible and actually how we are discovering new atoms. This process basically involves intense heat and pressure that creates extremely unstable atoms that are not found anywhere but the laboratory. That is how many of the unnamed elements (Uu_) were discovered, although they are to stable to isolate a... | [
"It is possible to change the number of Protons in a nucleus so one element converts into another. If I remember correctly, the name of the process is transmutation. It works by smashing smaller nuclei to larger nuclei to make a new elements.",
"Still, the process is very expensive, and it requires massive amount... | [
"Yes and no... By radiating one nuclide with something like neutrons, you can cause absorptions and transmute them into other nuclides. So yes you can and we do transmute nuclides all the time in reactors. For example oxygen absorbs a neutron and through some nuclear processes becomes a nitrogen atom. However, T... |
[
"Can organic matter be magnetic?"
] | [
false
] | I was bored so I decided to rip open a cigarette and run a magnet through the tobacco to see what would happen. Shockingly a few things were stuck to the magnet. I check to see if they were just getting stuck to the magnet but there was attraction as it would pull the bits. So are cigarette companies putting metal in c... | [
"Organic ferromagnets do exist, but they're a bit of a curiosity (they don't even have their own page on Wikipedia). If you have access to Materials Science and Engineering (Elsevier), you can have a look at ",
"this",
" review. Basically, materials that have high-spin polyradicals can form ferromagnets (and fe... | [
"There's all sorts of crap in cigarettes, I'm now curious what could be magnetic. Make a video- and do a comparison of a magnet and not a magnet, as well as cigarette and, say, dried tea, to show that A: we're really seeing magnetic attraction. and B: It's something specifically in a cigarette that's magnetic."
] | [
"I would say no. First, I believe your question is if organic matter can be attracted by magnets (to BE a magnet, that is to become a permanent magnet, is a whole other story), and the property of attraction by magnets is called ",
". Wikipedia has an ",
"excellent list",
" of ferromagnetic materials, and non... |
[
"Why is GPS more accurate at getting my cellphone location than cell tower triangulation?"
] | [
false
] | Is it just the accuracy of the times involved or is there something else? | [
" Individual cell towers can't pinpoint your location as effectively as GPS because they can't measure distance directly, whereas GPS receivers can. That inaccuracy means that GPS will almost always win over tower triangulation. GPS also uses something more sophisticated than triangulation to determine your distanc... | [
"relativity actually causes some 'substantial' drift for them. It is a REALLY tiny amount, but it is enough that after a few days without being updated from the ground, your GPS would start reporting you several meters away from your position, this error growing constantly.",
"Actually the amount is not tiny at a... | [
"There are two substations (probably more that are kept secret as a backup) and every time a GPS satellite passes within range, the substation updates the satellite so it is correctly set. This is very important because at the speeds the satellites are moving, and at the precision the atomic clocks are operating at... |
[
"By what mechanism do you become more flexible when you stretch daily?"
] | [
false
] | I started working out this year, and on top of the muscle, I've noticed that I'm massively more flexible, which I assume is due to my long stretching routine before working out. I know that muscle builds with use because it is damaged, then repairs itself to be even stronger. Do you become more flexible in the same way | [
"Tendons get damaged and repair the same way. Flexibility, anatomically speaking, isn't just about muscles. It is also about tendons. As extreme example, people who become demented or paralyzed develop contractures, where muscles and tendons become rigid over time (as in, they can no longer be stretched even by ano... | [
"So just bending down and touching my toes is doing some small amount of damage to my tendons, which they will heal and come back with a wider range of motion?"
] | [
"Little bit of elasticity can be added easily. Achieving olympics-level gymnastics flexibility would take quite a bit of training. It is same as with muscles in that sense. Also note that many usual muscle training exercises also have an effect on tendons."
] |
[
"How accurate is philosopher Slavoj Zizek's claim that in quantum physics, \"the idea is that the universe is a void, but a kind of positively-charged void. Particular things appear when the balance of the void is disturbed\"?"
] | [
false
] | [deleted] | [
"It's much too vague a statement to say anything meaningful about it. Also the universe appears to be charge neutral, why this is the case is not well understood, but ultimately must be related to charge conservation and whatever physics caused the early universe matter/antimatter asymmetry, the ladder still being ... | [
"Zizek's description sounds reminiscent of the Dirac sea - the positively-charged universe with just enough electrons to balance the charge. \"[T]hings appear when the balance of the void is disturbed\" could mean departures from this ground state to create observable electrons and holes.",
"I'm not sure Zizek h... | [
"As a general rule of thumb, whenever a philosopher talks about physics or quantum mechanics roll your eyes, extend your index fingers, angle your arms towards your ears and push inwards, creating a firm air-tight seal preventing the entrance of sound into the aural canal. This will help mitigate the headache res... |
[
"Does the Earth/Moon system weigh less than the Earth and the Moon would on their own?"
] | [
false
] | I'm reading about particle physics here so I'm likely to have made mistakes on both the small and large scales, but here goes: The energy in a system is distributed between movement energy and interaction energy. The negative interaction energy between a proton and an electron in a hydrogen atom is what keeps the whole... | [
"Yes, and the difference is about ",
"800 million tonnes",
". Sounds like a lot, but if you compare it to the mass of Earth or the Moon it's a very small difference."
] | [
"Is this assuming that 800 million tons of mass (converted to energy) originating from the Earth and the Moon would be used to move the Moon out of orbit?",
"It could.",
"It would make Earth and/or the Moon lighter depending on where you take it from, yes. The combined mass of the system would stay the same.",
... | [
"So a really hot object is more massive than that object near absolute zero?",
"Yes.",
"Energy in the center of mass frame matters."
] |
[
"On stomach bacteria"
] | [
false
] | The symbiotic relationship between us and the bacteria in our stomachs has always fascinated me. I know that, at a certain stage in utero, some bacteria flows from the mother to the offspring, but I had a few questions regarding that process and the process by which this relationship developed. What is the current stat... | [
"Swabbing the birth canal and inoculating like that is genius honestly. I have never heard of that. There are numerous studies about C-section babies having impaired microflora-",
"http://jn.nutrition.org/content/138/9/1796S.long"
] | [
"Swabbing the birth canal and inoculating like that is genius honestly. I have never heard of that. There are numerous studies about C-section babies having impaired microflora-",
"http://jn.nutrition.org/content/138/9/1796S.long"
] | [
"We are finding that some microorganisms actually utilize our signaling molecules such as norepinephrine and insulin",
"Can you explain more about this? I find this stuff fascinating.",
"It's my understanding that research is suggesting that to some extent our guts \"think\" for themselves. I'm sure this is a... |
[
"When the universe enters heat death, what will the average temperature of the universe be? Will it be absolute zero?"
] | [
false
] | Heat death as in all protons have decayed and all black holes have evaporated. (I realize proton decay and heat death are unproven theories, but I'm curious about what would happen in these scenarios). In heat death, there will be no more interaction between particles and no more baryonic matter, right? Does this mean ... | [
"The name \"heat death\" is a little misleading. It's often taken to imply that the Universe will be very hot in this end state. Rather, it's a condition where all the Universe's useful energy has been converted into waste heat. The eventual temperature could be 5K or 5000K - if everything is the same temperature, ... | [
"It'll be the opposite of absolute zero, in a sense. Absolute zero is defined as the temperature at which entropy is at a minimum, but the heat death of the universe occurs when the universe reaches maximum entropy (no further work can be done).",
"Temperature would still have a meaning - if some heat were myster... | [
"I'm confused about it being the opposite of absolute zero. That is correct, as absolute zero is indeed defined as minimum possible entropy, but does that mean the universe will be ",
" during heat death? How can that be? Also, why is absolute zero defined as minimum entropy instead of maximum entropy?"
] |
[
"Why is it that batteries cannot be charged quickly?"
] | [
false
] | It seems it takes no time at all to drain a battery but to charge it is just the opposite. What gives? | [
"chem eng here. well recharging a battery is reversing a chemical reaction and the rate at which you can do this is limited by the rate of ion transport to the electrodes. if you go pumping high voltage and current into a system which cannot react fast enough, you will risk decomposing your reagents and damaging th... | [
"Physicist here.",
"Can I assume that the battery is uniform and spherical?"
] | [
"It also exists in a frictionless vacuum."
] |
[
"Are speedreading school legit or a hoax, howmany words per second can the brain actually read retaining all the information?"
] | [
false
] | [deleted] | [
"I don't have any numbers on this but speedreading is legit. It's achieved by reading in chunks instead of word-by-word, and minimizing or even eliminating silent speech (don't think about the sound of the words while reading). However, while it's faster to get a general understanding of the text than traditional r... | [
"it is legit, but as you said it has pros and cons. pro: you can quickly get an idea about the general information of the text, con: it is not in-depth at all and you might skip some vital information which can obscure the main point"
] | [
"Every reading teacher knows that frequency can and should be increased in order to comprehend material. A rate of 90 WPM is necessary for the brain to maintain information while reading. By doing eye tracking exercises, the rate can increase to higher levels. Achieving a rate of 250 WPM is about 12th grade level. ... |
[
"Has the placebo effect been adequately studied?"
] | [
false
] | null | [
"What would that mean? Giving people sugar pills and telling them that they are actually medicine? That's not ethical... The goal is to develop a pill that does something over and above the benefit conferred by the placebo effect, and, if there is an effect, then that's good too (assuming the pill is effective -- o... | [
"There's a long discussion of both positive and negative placebo effects on the wiki for placebo... Research is ongoing to uncover mechanisms, although it seems like there may be many different kinds of effects..."
] | [
"I'm not really sure what you're asking / what kind of answer you are looking for. Yes, there is lots of research on the placebo effect..."
] |
[
"Does polarization take vector components of the electric field component of light?"
] | [
false
] | I'm trying to understand linear (I think?) polarization of light. The only way i can have it make sense in my brain is if the polarizing filter "selects" the vector component of the electric field parallel to the direction of polarization. For instance, take the typical exam question of 3 polarizing filters. 2 filters ... | [
"I'm not completely sure I understand your question, but a polarizer basically projects the vector onto the polarization direction. I think that's what you're saying. "
] | [
"You are correct. In the case that you described, about (100/sqrt(2))% of the light incident on the second and third filter should make it through, which is exactly what you would expect if the electric field vectors can be expressed as a pair of vectors on an arbitrary set of perpendicular axis."
] | [
"Exactly. Some polarizing filters are literally grates of fine wire, so that only electric fields perpendicular to the wire can get through. ",
"The fun part is that it happens even with only one photon, so it's not possible for this explanation to work at that small of a scale. This is an example of how Maxwell'... |
[
"If I attempted to hang myself from the ceiling of an elevator using a belt and it began to free-fall ... would there be slack in the belt?"
] | [
false
] | null | [
"Yes, always a little. The belt before the free fall would stretch a little resulting in an upward force that keeps you into place. As soon as the elevator starts its free fall, the tension would pull you towards the ceiling a little resulting in a slack. If the belt would be infinitely stiff, there would be the st... | [
"When the elevator stops will his head get ripped off?"
] | [
"Depends on the amount of time the elevator was free falling before it stopped instanteniously. When they are in free fall, the belt does not exert force around op's neck. when it stops suddenly the force around op's neck is dp/dt. dp is the transfer of momenta and dt is the time over which the acceleration changes... |
[
"Is there a principle that governs the distribution of the elements?"
] | [
false
] | Tried Googling the answer, couldn't figure out how to phrase it better, but I'm curious about the principles governing the distribution of elements - do the heavier ones occur with a linear or logarithmic amount less than the lighter ones? Is the distribution between elements 'smooth' or clumpy around certain elements ... | [
"Try looking up ",
"atomic abundance",
". In short, most of the matter of the universe was formed in the big bang. After that, elements are formed by a variety of processes, through nuclear fusion (light elements, primarily), nuclear fission (heavy elements), radioactive decay (nuclei that are unstable), and ot... | [
"The relative abundance of the elements in the universe is governed by the previous frequency of the nuclear reactions that form isotopes of elements, the stability of those isotopes, and the previous frequency of processes that transmute each nuclide. There are clusters of more abundant elements such as iron, but... | [
"There's no set trend at work here. Of course the most abundant element is Hydrogen and Helium comes a close second. Then, in your star cores you get what's called \"Helium Burning\" so you get elements like Beryllium, Boron and Carbon. That's what happens in majority of stars. The heavier elements will have to be ... |
[
"Does your finger print change as you grow? I.e. could you store the finger prints of babies in a database and they'd still be the same when the people were adults?"
] | [
false
] | null | [
"Finger prints have two characteristics: permanence and uniqueness. This means that every person has a unique set of fingerprints which only grows in size as a baby comes out of the womb and becomes an adult over time. Basic pattern remains the same. Age and the abrasive nature of some professions can just alter th... | [
"The skin may be wrinkled, but the pattern ingrained is the same. If you were to unwrinkle the skin (ie stretch it out) it would remain the same"
] | [
"Going off of this, what if one were to consider an elderly person? Would sagging/wrinkling of the skin have any affect on the similarity of the prints?"
] |
[
"What effects would I notice if I could adjust the circumference of my car wheels whilst driving?"
] | [
false
] | If I could somehow quickly and significantly change the diameter of the wheels on my car while travelling at a certain speed... would I slow down, speed up or maintain speed? Let's say 'significant' is adding a few inches to the front and back wheel diameter, and I'm driving at 100kmh. Apologies in advance for my inane... | [
"Essentially the same thing that happens when you shift gears. Making the wheel larger would be like upshifting; making it smaller, downshifting.",
"In fact that's exactly what's happening inside the transmission. When you shift up a gear, you're just moving to a set of gears where the drive gear (analogous to th... | [
"Perhaps, though in a typical passenger car, the wheels are only about 5% of the total mass of the car. The angular momentum of the wheels has only a small effect on acceleration.",
"A car enthusiast/racing magazine (Grassroots Motorsports) recently tested the effects of wheels with increasing angular momentum on... | [
"But if you think that the drive wheel is your pedals, the drive wheel is getting relatively bigger (to your gears)."
] |
[
"Why is americium used in smoke detectors rather than any of the other various radioactive elements?"
] | [
false
] | It seems to me like it would be easier to acquire something like uranium or thorium, since they have longer half lives. Does it have to do with the quantity of alpha particles they emit? | [
"Alpha radiation is needed because of it's relatively short mean free path. The idea behind smoke detectors is that there is a little detector close(ish) to the americium source. If there is not fire, the alpha particles can travel more or less freely to the detector which registers a current (alpha particles are... | [
"Americium has a half life of ~250 years, so practically it's going to last longer than fire codes would let you use it."
] | [
"It does. You want a lot of alpha particles (because they're how the device works) and as little beta or gamma radiation as you can get."
] |
[
"Why do creatures eat?"
] | [
false
] | Seems like a stupid question, but it occurred to me- Plants seem to me like a perfect lifeform to have dominated the earth. They had free and available energy and practically unlimited space to spread out and reproduce. Limited competition was necessary as the resources they needed were easy to get and came to them. It... | [
"This movement, and higher brain function, requires more energy than can be gathered from the sun.",
".....directly.",
"Animals have a really great strategy. They let the plants do all the work of concentrating the energy for them."
] | [
"Eating gathers energy more efficiently than photosynthesis, relative to weight of the energy gathering organs. If you look at plants, they typically do not have enough energy to move, whereas animals (which eat) can move very far/fast. This movement, and higher brain function, requires more energy than can be gath... | [
"You seem to be under the impression that photosynthetic plants are entirely self-sufficient. This is completely false. Photosynthetic plants have no way of fixing nitrogen, which is essential to survival. \"Fixed\" nitrogen is non-elemental nitrogen, in the form of nitrates, etc. Atmospheric N2 is unusable by most... |
[
"Why do antibodies for diseases like chickenpox stay in your body for years, while they only last a few months for other diseases?"
] | [
false
] | null | [
"There are white blood cells in your body that have memory, like a seasoned vet from a war. Some are hyper alert for signs of infection. Others pump out antibodies instead. Over time these seasoned vets die and their memory fades. This happens with the tetanus vaccine, and is why you need boosters.",
"Chicken pox... | [
"It gets a bit more complicated! Some extra factors are if the organism mutates frequently like the flu, which needs a new vaccine every year. This is like the virus strapping on a fake nose and glasses and walking past the guards.",
"Another factor is also how strong a reaction to your body the infection causes.... | [
"Thanks! I’m wondering about the evolutionary advantage of chicken pox hiding in neurons indefinitely. One might think that’s a clever strategy to stay alive, but as you said, it also keeps the immune system primed for future infections, which is ultimately to the detriment of the virus.",
"For these reasons, I m... |
[
"In layman’s terms, what are the differences between various units of “brightness”?"
] | [
false
] | I’m a fanatic of flashlights. I have a few powerful flashlights that are often described as being “brighter than the sun” by my friends when I show them off. What measurement could I utilize to compare the “brightness” of my flashlights to that of the “brightness” of the sun? I’m still a noob to the flashlight subre... | [
"This is actually an optics question (or radiometry, more precisely), not an astronomy one, although astronomy does have its own measure of brightness (or magnitude). The term \"brightness\" is measured by the photometric quantity \"luminance.\" Fundamentally, there are two types of units for measuring how things e... | [
"In astronomy there are more confusing units like \"absolute magnitude,\" but I don't know as much about those so I will let someone else handle that.",
"Magnitude is a type of unitless scale, and there are two types: absolute and apparent.",
"Absolute magnitude is a measure of how much light something emits, w... | [
"As I said, astronomers like to be confusing, so the lower the number the brighter the object.",
"Venus has an apparent magnitude of around -2 to -5, Sirius A the brightest star is around -1.46, Uranus is around 6.",
"6 is roughly the limiting magnitude for naked eye observations, with anything higher being too... |
[
"Shouldn't we be able to make a fairly accurate map of the visible (and not visible) universe, based on the galaxies we can see, their distances, speeds, accelerations, etc?"
] | [
false
] | [deleted] | [
"My very rough attempt at visualizing what a map of the universe might look like.",
"There is no \"centre\" of the universe, \"where the big bang happened\". Rather, as we look at distant galaxies, we observe that every single one is moving away from us (on your map, some are moving towards us). The observation t... | [
"no lots of people have noticed that, I wouldn't think too much into it though. humans are really good at finding patterns, even when they aren't there, and if there is some connection it is more likely something statistical than meaningful."
] | [
"no lots of people have noticed that, I wouldn't think too much into it though. humans are really good at finding patterns, even when they aren't there, and if there is some connection it is more likely something statistical than meaningful."
] |
[
"How do concentrated salt solutions kill bacteria?"
] | [
false
] | null | [
"By sucking them dry through osmosis. Bacterial cell walls are permeable to water, so when placed in an aqueous solution with more junk than is inside the cytoplasm of the bacterium, the water inside wants to get out and dilute the solution.",
"Some bacteria like saltwater, but you can always dissolve more salt i... | [
"Just to define osmosis:",
"Everything will naturally move from a high concentration area to a low concentration area - think of a drop of dye being dropped into a bowl of liquid. The dye naturally spreads through the liquid until its spread out (low concentration) instead of staying in one drop (high concentrati... | [
"Because proteins require water molecules to fold properly and to be dissolved in the first place. Removing all the water will cause the proteins (and all other biomolecules, like DNA) to form crystals. Upon rehydration those might dissolve again, but most likely they won't do so in the correct conformation (and so... |
[
"Do protons and neutrons touch each other within the nucleus an atom?"
] | [
false
] | We’ve all seen the models of atoms which show a pile of protons and neutrons, making of the nucleus. Is this model accurate? More specifically, is there a measurable distance between the individual protons and neutrons, or are they “touching” in the way people normally use the word? | [
"They don't have well-defined positions in space, but we can talk about the spatial extent of their wavefunctions.",
"Heavy nuclei (A ~ 100) have radii on the order of ~ 10 femtometers, while a bare nucleon has a radius of around ~ 1 femtometer. So in heavy nuclei, protons and neutrons are packed very tightly tog... | [
"Quarks are identical particles just like electrons. So if you want to describe the quantum state of a nucleus in terms of quarks, it still has to be antisymmetrized with respect to exchange of ",
" two identical particles.",
"But most nuclear structure models (the exception being lattice QCD) ignore quarks and... | [
"At that scale are quirks still clearly associated with individual baryons, or is it like valence electrons in (some) molecules where they can move between atoms, or are not clearly associated with any single atom?"
] |
[
"Are flies and other bugs aware that we are trying to kill them when we swat at them?"
] | [
false
] | null | [
"AFAIK, the brains of creatures like flies (and pretty much all bugs) give the creature drives (find food, mate, etc) and instinctual responses (avoid dying), while equipping them with the software to process external stimuli to such an extent that it allows the creature to respond to the environment in useful ways... | [
"Do they forget as soon as they dodge our hands what just happened?",
"Insects can be conditioned to avoid something that they find attractive. ",
"http://www.jneurosci.org/content/31/20/7240.full",
"\nBut conditioning takes more than one instance of danger in a location where there is something attractive (s... | [
"This really can be reduced to the question \"Are flies and other bugs aware?\" ",
"The answer to that depends very much on what you think 'aware' means - but in a simple sensory way, yes, of course they are aware of the stimulus of a fast-moving thing near to them, that's how they are able to move away from it. ... |
[
"In large desert plains around the world, is there less oxygen in the air?"
] | [
false
] | Given that flora whilst in photosynthesises creates oxygen, and a desert generally lacks flora and in most cases fauna as well. Would this result in less oxygen than average? as I've learnt to be approximately 19-21% | [
"There might be some small variations in oxygen content, but the amount is going to be very small. Here is my reasoning. Plants make O2 from the CO2 in the air. CO2 has a current concentration of 400 ppm. Even if the plants could take all the CO2 and make it into oxygen (they can't, but as a best case scenario) ... | [
"I doubt there would be any noticeable difference to a human. Currently, Earth's atmosphere is composed of approximately 200,000 ppmv oxygen or about 20% of the total gases in the atmosphere. If you believe there would be less oxygen then it has to be replaced by something else which you imply would be CO2 due to l... | [
"wow, didn't realise plant breathed oxygen at night, learn something new everyday"
] |
[
"Is cannabis a vasodilator, or vasoconstrictor?"
] | [
false
] | I've seen many conflicting arguments online. Forums say it's a dilator while some websites say it is a constrictor. | [
"The active ingredients in cannabis activate receptors of the endocannabinoid system, which is widespread throughout the entire body and brain. These receptors come in a variety of forms (the three most popularly studied of which are called CB1, CB2, and GPR55/CB3, although there are others besides these), and the ... | [
"It's reasonably ubiquitous to assume the different ",
"terpenes",
" in the pollen produce different effects other than just aromatic diversity."
] | [
"It's reasonably ubiquitous to assume the different ",
"terpenes",
" in the pollen produce different effects other than just aromatic diversity."
] |
[
"While in High School, my science teacher explained evaporative cooling as \"the warm molecules evaporate, leaving only the colder molecules behind\". This didn't sound completely right then, and still doesn't now, is it?"
] | [
false
] | [deleted] | [
"Check out the ",
"Maxwell-Boltzmann distribution",
" for the speeds of gas molecules at a given temperature. You will find that there exists molecules with a wide range of kinetic energy."
] | [
"The language is a bit wooden, the way you quote it, but you could say that is indeed the case. Not all molecules have the same speed, and of course the fastest ones are more likely to escape."
] | [
"Temperature is a statistical value. It doesn't make much sense to speak of the temperature of one molecule. But if by \"warm\" you mean \"which has an energy higher than the average for a distribution of molecules at this temperature\" then it's absolutely correct."
] |
[
"Why must steam from a turbine be sent through a cooling tower?"
] | [
false
] | It seems like a pointless waste. Why isn't the steam, for example, sent through pipes and used to preheat the feed water? I do understand that water must be cold before it can be used to drive a turbine. But why can't you cool it off by transferring heat to the water that has already entered the heating phase? Apologie... | [
"Thermodynamically speaking to get energy from the steam you have to have a flow of heat. so with out a cold spot to dump that heat you have no way to power the turbine.",
"secondly a bunch of power plants never use evaporation cooling, They just use a single pass water source such as a river. The places that do... | [
"Actually, Water must be hot (its usually superheated steam) to run a turbine. Turbines work by lowering the enthalpy of the fluid driving them, and to have high enthalpy a fluid must be hot. What you don't want is the steam condensing inside the turbine as that will damage the turbine.",
"Outlet steam often is u... | [
"Your third sentence is correct. The vapor leaving the cooling tower is only used to absorb heat from the condensing of the steam loop and is evaporated off.",
"Depending on the cooling tower and design of the plant, that visible vapor is usually not \"steam\" as in superheated vapor. The actual temperature of ... |
[
"Why are ppm and mg/kg used interchangeably in some fields?"
] | [
false
] | I'm a physician looking through some environmental science literature. I've noticed that ppm and mg/kg are being used as synonyms. However, remembering my chemistry, it seems that you'd need to account for the molar masses of your compounds to convert from one measure to the other. So do these terms represent a mass fr... | [
"You are right; ppm are count ratios aka molar ratios, whereas mg/kg are weight ratios. They are only interchangeable if weight-to-count ratios, aka molar masses, are the same for the numerator and the denominator. ",
"Without knowing which fields you are talking about, it's hard to say how they justify the assum... | [
"ppm is an ambiguous term, just like how percent solution can refer to %v/v, %v/w and %w/w. ppm doesn't specify what a \"part\" actually is. It can be a part by moles, a part by volume or a part by weight. If we use use weight/weight, 1ppm= 1/1000000=1mg/1000000mg."
] | [
"I've actually been working with mycotoxins for the past year and we use ppm and mg/kg interchangeably because we are assuming a weight ratio. For example, in a sample of corn you might find 20 ppb of aflatoxin. In plant pathology that would equal 20 nanograms per gram. When we use the parts per notation we are usi... |
[
"Can I have an \"electricity leak\" similar to how I can have a water leak in my house that will drive up my electric bill?"
] | [
false
] | null | [
"Exceptions to this are if you have wiring that is creating a short somewhere or allowing power to flow to ground",
"so the answer is, yes you can. I mean, how hard is it to find a ground?"
] | [
"The answer given by ",
"u/brandonsmash",
" is completely wrong. You absolutely can leak electrical current from your house to ground, and it would increase your electric bill. It is usually difficult to do, but happens quite often due to poor wiring, or workmanship. \nSource: am an electrician and have observe... | [
"In short, you can't have an \"electricity leak\" but it is possible to have a circuit that uses current despite being nominally off.",
"That sounds exactly like an \"electricity leak\"."
] |
[
"Why haven't plants evolved the ability to fix nitrogen from the air to use for growing?"
] | [
false
] | Why are only things like bacteria capable of performing this reaction? The amount of free nitrogen in the air is enormous, if a plant could use this for growth and reproduction, the evolutionary advantage would be huge compared to normal plants, since nitrogen is often the major limiting nutrient in soils. What is it... | [
"While I don't know the exact underlying genetics (see edit), but I think I can partially answer the question from an ecological perspective. The reason is likely to be that it would be less competitive for the organism to do the process itself than having another organism (bacteria) to accomplish the task. That's ... | [
"Just wanted to add to the above response - ",
"cyanobacteria",
" are capable of both photosynthesis and nitrogen fixation. To circumvent the incompatible environmental requirements, one will observe differentiation in cyanobacteria, culminating in the formation of ",
"heterocysts",
". "
] | [
"Just wanted to clarify that not all cyanos can fix N, it's mainly organisms in the nostoc and oscilllatoriales that can do it. Also i'll mention that the oscilllatoriales are paraphyletic, and many of the genus names (leotolyngbya, anabaena, ",
") are paraphyletic as well. You can blame the water quality people ... |
[
"Is there an equal amount of matter as there is anti-matter in the universe?"
] | [
false
] | null | [
"No; there's more matter than antimatter, to the point that almost all of the stuff floating around in the Universe is what we'd call matter. This is one of the bigger mysteries in physics, since generally you'd expect the two to have been created in equal amounts in the early Universe. There are speculative theori... | [
"Antimatter stars or galaxies would produce and emit antimatter particles that would, when coming into contact with the normal interstellar or intergalactic medium, produce energy from annihilation. We haven't observed any such energy, so we're fairly sure we haven't seen any structures like this."
] | [
"Given enough antimatter ingredients, yes, they'd behave just like matter and form atoms, molecules, planets, proteins, and overpriced sushi restuarants. Chances are, however, that there isn't much antimatter out there."
] |
[
"What is the practical reason diplomatic immunity exists?"
] | [
false
] | [deleted] | [
"Consider that, in even the most Freedom loving countries, finding a reason to arrest and incarcerate someone is a trivial matter. Meaning a government so inclined to lock someone up can find the pretext to do so.",
"However, there is the knowledge that, what we can do to theirs, so they can do to ours, so it is,... | [
"It's to prevent an ambassador from being persecuted, framed, prosecuted, etc. in performing their duties -- Especially during chaotic times such as wartime. ",
"In the case of a crime being committed that is not related to their duties on the job the host country would generally waive the diplomats immunity and ... | [
"Everyone has been mentioning extreme examples of the government purposely trying to get the diplomat. There are other reasons, like not arresting the diplomat for something they didn't know they couldn't do here but could in their country, turning right on a red light, or smoking weed. "
] |
[
"Why do we square then square root in standard deviation, as opposed to simply taking the modulus of all values? Surely the way we do it puts additional weighting on data points further from the mean?"
] | [
false
] | null | [
"You are absolutely correct. The choice of variance/standard deviation as a go-to metric for population variability has been contested, for exactly this reason. A more direct & sensible metric would be the ",
"absolute mean deviation",
", i.e. f(x) = | x - µx | for a random variable x. However absolute values m... | [
"More generally, there's the concept of the p-norm, which is defined by ",
"||x||",
" = (|x",
"|",
" + ... + |x",
"|",
")",
".",
"So the cases you're talking about in the title are p = 1 and p = 2.",
"You can see visually what surfaces of constant p-norm look like in two dimensions ",
"here",
... | [
"In addition to the absolutely correct things that have been said by others, I'd add the fact that the standard deviation is related naturally to the normal distribution, and the normal distribution arises naturally through the central limit theorem. So if you accept that calculating averages is a \"natural\" thing... |
[
"What are some of the most controversial science/tech issues today?"
] | [
false
] | null | [
"You'll have a hard time finding something which is \"socially/politically relevant\" AND the subject of actual scientific debate. Most political issues involving science have a fairly clear scientific consensus. ",
"Though \"debate\" is perhaps the wrong word, the effects of nano-materials on health is an up an... | [
"Haha, that's nice of you.",
"I won't be done for a few months. But perhaps I'll keep you posted."
] | [
"Haha, that's nice of you.",
"I won't be done for a few months. But perhaps I'll keep you posted."
] |
[
"If mRNA vaccines remain proven safe, is it actually necessary to go through new trials each time when vaccinating for a new strain or another disease?"
] | [
false
] | Obviously it's best to be careful about these things. That said, with this new form of vaccination, a lot of the uncertainty of 'old school' vaccines is out of the picture, right? Supposing the method of getting mRNA into the body remains the same, and the proteins produced are innocuous – is there still reason to thin... | [
"For a completely new virus, sure - you'd definitely need new trials.",
"For a modified vaccine targeting a new strain, probably not in the long term (maybe the first few times it's done for a given vaccine). Or greatly reduced compared to the original trials. ",
"Inactivated virus and protein based COVID vacci... | [
"In addition to human safety, vaccines are generally only approved it they are effective.",
"So even if you're 100% sure of the safety of an mRNA delivery system, you still have to perform trials to see if it actually works."
] | [
"Phase III trials indeed can take a long time and a large number of people. But you have to do it the hard way, waiting for people to naturally get infected and seeing if the vaccinated group had less infections than the placebo group.",
"The Phase II trials are the ones that primarily look at antibodies. The pre... |
[
"Do theoretical physicists represent observation abstractly in mathematics? If so, how?"
] | [
false
] | I have the vague understanding that all possible values of a quantum measurement get modeled mathematically as a probability wave that collapses on observation. For example, I recall Richard Feynman explaining the uncertainty principle. He said no matter what you do, you can't know the heading and position of a certain... | [
"Yes, the mathematical operation indicating observation of a quantity is given by the corresponding Hermitian operator. For example, with appropriate assignment of axes and such, the (one dimensional) position operator is just x, the momentum operator is -i * hbar * d/dx, and you can directly show that momentum a... | [
"You're answer was fine, but I felt compelled to point out that your derivation of the commutator of x and p is not formally correct. The answer is correct, but to be rigorous you should act the commutator on a state, i.e. [x,p]|psi>= ...",
"I just didn't want anyone to put that on an exam or anything."
] | [
"Thanks! I'm not sure I understand the math. but I think I get the gist. You're saying that position * momentum != momentum * position and so whichever observation you do first changes the value you get for the other.",
"I guess what I was really asking was whether the observer was actually represented in the equ... |
[
"Do photovoltaics or fossil fuels generate more pollution per kilowatt of power?"
] | [
false
] | Specifically, is the pollution created during the manufacture of photovoltaic material greater or lesser, per kilowatt of power, than the pollution created by the conversion of fossil fuels to power? | [
"The nice thing about solar cells is that they generate no pollution or CO2 emissions when they produce electricity, however, you are right that they require an input of energy for their manufacture with all the associated generation of pollution and CO2. To gauge whether solar cells still provide a net plus from a... | [
"That chart is almost certainly the result of a cradle-to-grave ",
"Life Cycle Assessment",
". In wiki's own summary:",
"Cradle-to-grave is the full Life Cycle Assessment from resource extraction ('cradle') to use phase and disposal phase ('grave'). For example, trees produce paper, which can be recycled int... | [
"Silicon is not mined like iron or coal. It is reduced from silicon dioxide- sand mines, or quartz rocks. You drive out to a desert, shovel a bunch of sand, and drive back. No fuss, no mining. Its a billion dollar industry in the US and most of it is done in Texas. Silicon makes up 28% of the crust and silica ... |
[
"How come old people have a circle on their upper arm?"
] | [
false
] | It looks like a weird circle shaped imprint and I'm not sure how to describe it but its usually like the top of their arm on the side facing out. Not all people have it but it seems mostly really old ones have one. I don't know a single person my age with one, does it just grow later on? | [
"It's a smallpox vaccination scar. Pretty much all kids in developed nations used to be vaccinated for smallpox, and just about every kid in the world was vaccinated from the late 60s to early 70s, till the disease finally died out, due to a massive coordinated worldwide vaccination effort organized by the World He... | [
"The round mark on the upper arm that the OP is describing is classic for the smallpox vaccination. It was typically on the left upper arm and is about the size of a dime. ",
"Here's",
" a popular press article and ",
"here's",
" a picture of a typical smallpox vaccination scar.",
"There was also an ongoi... | [
"This is a good answer. ",
"I'll add that sometimes you'll see ",
"similar scars",
" on younger people from other countries. These are likely BCG vaccination scars. The BCG vaccine is an anti-TB vaccine used in some parts of the world, although it isn't used in America due to variation in and controversy over... |
[
"Is there evidence for long-term variation or change in our physical constants?"
] | [
false
] | I work in an EMC test house and often have to consider the accuracy of my measurements and the instruments used in those measurements. To ensure that our equipment is giving us good data, we have to periodically send the equipment to calibration labs, where they go through a battery of tests. I'm not an expert on the... | [
"Can you clarify your question, please? Are you asking about physical constants, or are you asking about experimental precision? If it's the first, the answer's no, and if it's the second, that's just engineering and repetition."
] | [
"What I'm trying to posit is that the change in accuracy of a single measurement device or groups of the same device over time would imply, with several degrees of separation, that there is change in the constants. I realize now that the kilogram was a poor example to use since mass is directly tied to the amount ... | [
"Except not really. The Webb paper that first suggested that turned out to have a catastrophic methodological error that invalidated the results."
] |
[
"If you are living in a cold country, is it still necessary to buy efficient light bulbs?"
] | [
false
] | [deleted] | [
"You have a good point. Such a good point in fact, that when the EU banned incandescent bulbs a German businessman started importing them as \"heat balls\".",
"The funny thing about this is that incandescent bulbs are fairly efficient when they are used as heaters, throwing off around 95 percent of the energy the... | [
"They certainly generate heat, but there are better ways of heating. ",
"Heat pumps",
" are much more efficient, as they move heat around rather than just generate it.",
"If the temperature difference between outside and inside is not too great, they can warm the room by 3 to 4 times more than a resistive hea... | [
"Ha, I like that!",
"Do you think that there are figures to back this claim up?",
"Edit: just noticed the relevant username!"
] |
[
"The 'book detector' when I walk in/out of my university's library causes a high pitched sibilance in my earphones. Why?"
] | [
false
] | On entry or exit at my university's library, stock standard iphone 5 earphones let out a high pitch noise while listening to music. Why? | [
"The book detector is emitting a radio signal which would energize and RFID chips in the book detector tags. Your earphones are acting as antennas and picking up the signal. You can sometimes get the same effect if your phone is sending/receiving a lot of data near some speakers."
] | [
"Kind of like how many MP3 players wouldn't play FM radio without anything plugged into the headphone jack (to act as an antenna). Even my bathroom alarm clock/radio uses its power cord as a receiver for FM."
] | [
"Kind of like how many MP3 players wouldn't play FM radio without anything plugged into the headphone jack (to act as an antenna). Even my bathroom alarm clock/radio uses its power cord as a receiver for FM."
] |
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