title list | over_18 list | post_content stringlengths 0 9.37k ⌀ | C1 list | C2 list | C3 list |
|---|---|---|---|---|---|
[
"Are photoelectrons always emitted at maximum kinetic energy? If no, why not?"
] | [
false
] | Question about the photoelectric effect, using the formula KE(max) = hf - work function we can calculate the maximum kinetic energy of photoelectrons. Are photoelectrons always emitted at this maximum kinetic energy? If not what other factors are affecting them? Thanks! | [
"I'm not happy at all with the explanation given here, so let me try as well.",
"The answer is actually simple: no, photoelectrons are not always emitted at maximum kinetic energy. In fact I can show you what you get:",
"This is a spectrum of monolayer MoS2 on Graphene on Iridium taken with 370eV excitation ene... | [
"You still get photoemission in a vacuum (in fact modern photoemission experiments are all done in ultra-high vacuum chambers because the mean free path of electrons is very short in a gas). However, if your metallic sample is not grounded, the surface will be charged as the electrons are emitted. The surface will ... | [
"I also need some help regarding photoelectric effect topic. Can you please help me with it"
] |
[
"Why are electric bills in units of Watts?"
] | [
false
] | Power is defined as an energy/sec, so I'm wondering why electric bills are measured in kW. I would think it would charge you for the total energy you draw over the month. Is the measurement an average of the energy drawn per sec (total energy/secs in month)? | [
"They actually charge you per kilowatt-hour (kW·h), which I suppose is handier than charging you per 3.6 megajoules (MJ), to which it is equivalent."
] | [
"Like adoarns said, you're actually not charged in kW. You're charged in kWh, kilowatt-hours (read: kilowatts*hours). Since watts are in units of energy/time, multiplying by hours cancels the time units and gives you energy. ",
"One kilowatt hour is the amount of energy consumed by drawing a kilowatt for an hour.... | [
"I finally memorized this equivalence a little while ago. Makes comparisons of energy so much more useful. I don't understand why anybody would want to use the kWh as it has 2 different time units."
] |
[
"Is it possible for sexual selection to select for traits in a runaway fashion that ultimately causes the demise of a species? If so, are there any examples of this?"
] | [
false
] | [deleted] | [
"http://www.sciencedirect.com/science/article/pii/S002251939690096X",
"http://rspb.royalsocietypublishing.org/content/270/1526/1793.short",
"http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1691875/",
"Extinction doesn't tend to just happen. If an organism is non viable it dies out and more viable organisms can co... | [
"my previous comment was incredibly over simplified yes, however as the paper below shows (see link) sexual selection did cause the elks antlers to become detrimental to its fitness, which in turn could have been one the leading causes for extinction :)",
"http://www.duluth.umn.edu/~rmoen/Dld/Moen_1999.pdf"
] | [
"Well they aren't extinct yet but sexual selection can definitely get carried away. The example used in my animal behavior class was the ",
"long-tailed widowbird",
". Check out the poor guy trying to ",
"fly",
"."
] |
[
"Are there any forms of scientific inquiry into the efficacy of 'alternative medicines?'"
] | [
false
] | I'm curious if there have ever been any rigorous studies of 'alternative medicines.' I've met people who believe so fully that non-traditional medicines are some kind of secret miracle cure that western science denies for the sake of money... but is there really any proof for this? Googling around pulls up loads of qua... | [
"Yes. But there's no such thing as 'alternative' medicine. There's medicine that's been shown to work, and medicine that hasn't.",
"For example",
"Instead of google, try google scholar. It'll weed out the crap a bit better."
] | [
"Oddly enough, ",
"this infographic",
" is a pretty cool start. Not a medicine person, so I'll decline to comment further",
"edit: clicking on the bubbles in the infographic connects you to the scientific study behind that specific treatment (and whether it was efficacious or not) "
] | [
"Coincidentally the comment I said that sparked off a huge debate was 'Alternative medicine that works is called medicine.'"
] |
[
"Based on probability and how the universe is ever expanding..."
] | [
false
] | null | [
"The universe is expanding but not infinite. There isn't more universe it just gets larger, space expands. The quantity of mass and energy is finite."
] | [
"That said, the universe is very very vast and the probability of other life, however improbable is still quite likely."
] | [
"The ",
" universe isn't infinite, but the universe itself is probably infinite."
] |
[
"Are there any documented differences between men and women's swimming skills?"
] | [
false
] | [deleted] | [
"The idea of women and children first is rooted in chivalry. It has no real basis on men or women and their swimming ability.",
"Scientifically though women naturally have more body fat than men which makes them more buoyant than their male counterparts. "
] | [
"Like for any athletic task, ",
"the top men always outperform the top women.",
" ",
"Women's lives are instinctively valued more because population growth is more limited by available females than by available males when it comes to reproduction. However, this does not make it \"right.\""
] | [
"I meant humans, as I started the sentence with talking about women. However, this would still hold across the animal kingdom: sperm is cheap, eggs are expensive... population growth, all else equal, is more limited by female numbers than male numbers. "
] |
[
"How does body shape relate to swimming performance ?"
] | [
false
] | Here is a question from my swimming class. We have noted that girls are usually faster with kick exercises, whereas boys are faster with arm practice. Boys think it has to do with the distribution of body fat (or possibly body shape), and girls think we are just lazy (and that we shouldn't be so rude!). Has there been ... | [
"Disclaimer: the mechanics of a human body -- with all of its density variations, oddly shaped limbs with multiple joints, varying cross sectional area, etc -- moving through a fluid like water can get pretty complicated if you try to break it down and analyze how men and women might be better at one type of stroke... | [
"Generally, the amount water you can pull affects ability the most. Men usually have wider shoulders, while women have larger hips. Also I doubt the distribution of body fat will much affect performance, except in large differences."
] | [
"http://forum.slowtwitch.com/cgi-bin/gforum.cgi?post=1733839",
"\n(Study on facial hair",
"3) Stubble of an average 1.2mm was marginally more slippery than smooth skin. Shorter stubble failed to trap the water; longer stubble encountered the \"beard drag\" effect of (2). ",
"4) Goatees where pointed and dense... |
[
"AskScience AMA: I'm Vinny Lynch, assistant prof. of human genetics at UChicago. I led one of two research groups that independently found why elephants don’t get cancer as frequently as we thought they should (Spoiler: 20 copies of the p53 tumor suppressor gene). AMA!"
] | [
false
] | Hi, I’m , assistant professor in the Department of Human Genetics at the University of Chicago. A while back, I got interested in Peto’s Paradox: the observation that big and long-lived organisms like elephants and whales don’t get cancer as often as we think they should. If all cells have a similar risk of developing ... | [
"Hi Vinny,",
"Does your work have a therapeutic end goal or is it just basic research?",
"Is P53's mode of action well understood?",
"What do you think of the potential for CRISPR and related technologies for treating cancer by selectively targeting sequences of DNA, if that's not too far outside the scope o... | [
"Yes p53 is one of the well understood gene mutation leading to cancer. It is mutated in The majority of cancer cells. It is basically a checkpoint before the cell divides that checks and make sure that the cell's DNA hasn't been mutated too much. If the DNA is too mutated p53 sends signals for the sell to self des... | [
"Fellow medical student here.",
"I've taken several tests that ask about p53. At your level, you also need to know that p53 (after irreparable DNA damage is ascertained) recruits BAX to knock out bcl2; this destabilizes mitochondrial membranes in the cell which allows cytochrome c to leak into the cell. Cytochrom... |
[
"It's never happened before but what would it take for a new Presidential election to commence?"
] | [
false
] | null | [
"Such questions are better suited for some polisci sub"
] | [
"I was thinking so. Do you have a recommend?"
] | [
"Not sure. There may even be one specific to US politics or constitutional law."
] |
[
"What is the most optimal procedure for caloric intake?"
] | [
false
] | Is it better to have a consistent amount of calories eaten throughout the day (400 calories every three hours) or to have it staggered in some way? (600 calories in the morning after exercising followed by a combination of 150 and 300 calorie meals alternating throughout the day or any other kind of pattern fitting thi... | [
"here are some good reads",
"http://www.leangains.com/2010/10/top-ten-fasting-myths-debunked.html?m=1",
"http://www.leangains.com/2011/01/better-blood-glucose-with-lower-meal.html?m=1",
" ",
"http://www.leangains.com/2011/04/critique-of-issn-position-stand-on-meal.html?m=1",
"http://www.alanaragon.com/an-... | [
"there has been some research that suggests that unorthodox eating schedules such as alternate day fasting might be beneficial, but there isn't enough evidence either way really. as for the six meals a day vs x thing, it's a myth."
] | [
"Well, first, you would have to define optimal. There is no way to optimize the amount of calories you can get from food, the calories you can theoretically get from a spoon of sugar are the same if you take a whole spoon at once or break it on 3 teaspoons."
] |
[
"Do stranger forms of life get sick; like jellyfish, amoeba, or fungi?"
] | [
false
] | Just to clarify, do jellyfish get sick? What about even stranger or simpler creatures, like amoebas or fungi and mold? Do they fall ill to infections? How do they combat them? What are some of the more odd immune systems of the planet's strange creatures? | [
"Even bacteria can get sick.",
"Bacteriophages are viruses that infect bacteria. There are ",
" of them, in oceans and in soil and in you.",
"Some bacteria cope with constant viral assault by having thick peptidoglycan cell walls, by secreting a thick layer of mucus over the bacterial colony, and by trying to... | [
"There isn't really a hard and fast definition for life in the first place, so I'm sure you can find biologists who consider viruses to be alive. However, since viruses are so simple, any definition of life that includes them is likely to include other things we might instinctively label as non-life, like say prion... | [
"Do viruses seem to share a common ancestor with other life, or are they so simple the could have formed independently? "
] |
[
"Do any animals show a tendency to be left or right \"handed\"?"
] | [
false
] | I was wondering if any research has been done to show if other animals have a dominant hemisphere of the brain, or if it would be some kind of disadvantage in the natural world. | [
"A lot of animals are right or left \"handed\" it’s been proven multiple times.\nMost untrained horses will lead with their right leg as most are \"right handed\". Therefore many racing tracks are counter-clockwise to favor \"right handed\" horses. Also many trainers put blinders on the left eye of their horses wit... | [
"Watched this earlier ",
"http://www.youtube.com/watch?v=DU3OdTLuHf0&feature=g-all-a&list=PL8B1DDE384770FD97&context=G2f8288bFAAAAAAAAAAA"
] | [
"Source?"
] |
[
"Can you have light without heat? Can you have heat without light (infra red)?"
] | [
false
] | So, I was thinking, if infra red is hotter than the other colours in the spectrum, is all heat infra red? If infra red sensors can pick me up from a helicopter, does that mean my heat is sending off light through heat and therefore at light speed? Also on the subject, if there is little matter in between the sun and an... | [
"The other responses seemed a little confusing, so I'll give another. I think where some of your misunderstanding originates is when EM waves are introduced in schooling, infrared waves are called heat waves.",
".",
"Everything at a temperature above 0K (so everything) emits some sort of electromagnetic radiati... | [
"Can you have light without heat?",
"If you define heat broadly as energy, then electromagnetic waves of all wavelengths carry heat, because all EM waves carry energy. If you define heat as the temperature of matter being increased, then EM waves do not carry heat, but they do carry energy which is usually partia... | [
"Heat is basically a measure for the average amount atoms are 'jiggling'.\nSince light isn't made up of atoms it does not have any temperature, so infrared isn't 'hotter' than other colours. ",
"Objects give of light when they're heated: think of a piece of metal that is glowing because it has reached a very high... |
[
"Why can't magnet bend light when light is made out of electromagnetic wave?"
] | [
false
] | Light is made out of electric field and magnetic field. So why can't magnet interact with the magnetic field part of light? | [
"It can, but it doesn't bend the light's path. Instead, it bends the polarization. This is called the Faraday effect. (",
"https://en.wikipedia.org/wiki/Faraday_effect",
")"
] | [
"The electromagnetic field doesn't interact with itself, except at very high energies and very small distances which are not relevant here. This means that the magnetic field of the magnet won't affect a passing EM wave. The wave can be affected by the magnet itself, though, by moving the electrons inside it, which... | [
"Interference specifically tells you that they're NOT interacting. If I have field E1 and another field E2, the total field is just E1+E2. That's the behavior of NON-INTERACTING phenomena, they just ignore each other and add. If they WERE interacting then the field would not be the sum but rather some entirely new ... |
[
"Why is the human body unable to break down corn?"
] | [
false
] | null | [
"If you are talking about seeing it in your feces, that's only the skin which is tough cellulose. You have digested the inside. The human digestive system can't break down most cellulose, grass, plant stems, skins of some fruits, etc. Herbivores have digestions that can extract more nutrients from it, e.g. cows wit... | [
"Exactly, cellulose is a type of starch that plants make (usually in their cell walls). Starch, and even glycogen which our bodies can break down are polymers of glucose molecules. ",
"This is because our enzymes to break then down expect a certain 'shape' to bind to. That shape is due to the alpha-1-4 glycosidic... | [
"Corn has lots of cellulose, the same stuff found in the cell walls of plant cells. Cellulose is a sugar, but is mainly used as a structural material. Human bodies do not possess to enzyme to break it down, and hence just pass it through the digestive tract. The enzyme is called cellulase.",
"Ever wonder how cows... |
[
"If birth control prevents ovulation, why don't women hit menopause later?"
] | [
false
] | I am talking about the pill which if I understand correctly prevents ovulation which is why one cannot get pregnant. I also know (presume?) a woman is born with all the eggs she will ever have, and menopause happens when a woman "runs out of eggs". If this is true then shouldn't there be a backup of eggs for a woman to... | [
"First, women never “run out of eggs.” The ovaries contain hundreds of times the number of ovum that a female will release throughout her lifetime. ",
"Menopause occurs due to hormonal changes that come with aging. So your speculation that there is some sort of “biological clock” is sort of correct (it’s just mor... | [
"If an egg is not ovulated is goes to waste. In fact eggs are maturing in batches every day in the ovaries, regardless of the point in the cycle, and regardless of whether the woman is pregnant or not. The mature egg will only be ovulated if the hormones are right at the time it reaches maturity, othersise it's rea... | [
"Really makes you appreciate how rare it is to even exist when you think about how small the chances are that you are you at all..."
] |
[
"Does a computer monitor consume energy at different levels depending on the color of the items being displayed?"
] | [
false
] | Basically, I'm wondering if a monitor displaying bright, white colors most of the time will consume more energy than one displaying mostly dark colors. Assuming all else being equal, of course. | [
"To a first approximation, the answer is that it doesn't matter. Almost all modern computer monitors consist of a liquid-crystal display in front of a white backlight (either LED or fluorescent). Each pixel of the display has transparent electrodes on the front and back, and when an electric field is applied, the p... | [
"This kinda confirms my suspicion, but I learned a great deal from your response. Thanks a bunch!"
] | [
"I'd love to hear an analysis on the old cathode ray tube monitors we used to use up until a decade ago. I know the basic workings, but not enough to know if there's a difference in power draw based on what colors are being displayed."
] |
[
"How can some animals eat just one thing and get all nutritions and vitamins and all that?"
] | [
false
] | We need to eat a balanced diet to get everything we need. Some our bodies can just create (classic vitamin D using our skin), but others we just have to consume. How can certain animals (how many are there? What is the percentage) just eat one thing. Like blue whales only eat krill. Does Krill just happen to contain ev... | [
"Humans can't make their own vitamin C. Apes can't either. Other animals produce vitamin C in their liver. So, fresh liver is a good source of vitamin C. ",
"Worth remembering if you are ever decide to leave civilization and hunt for food. "
] | [
"Put simply - they have evolved specifically for the diet they have and rarely anything else. This includes everything from their teeth, to their gut bacteria, and even down to their specific metabolism. ",
"For example, think of the koala. Koalas ONLY eat eucalyptus leaves. And, not just any eucalyptus leaf. The... | [
"Look at it the other way. Imagine the primate ancestors of humans, eating a variety of foods. Meat, nuts, fruit, etc. It would be highly unusual for them to, for example, have vitamin c deficiency. So if they had the ability to make vitamin c, which they did, but that ability got broken due to mutations, which it ... |
[
"Does the moon's gravity significantly affect a satellite's orbit?"
] | [
false
] | Specifically was wondering about geosynchronous orbits since that's ~23K miles up and doesn't experience the atmospheric drag that say the ISS does. If so, how does it change it (meaning altitude, speed,eccentricity,etc.) And what is the net effect? | [
"There are usually so many other factors affecting a satellite's orbit that the satellite is constantly adjusting itself anyway. When satellites go into orbit, they take account for the moon's gravity, as well as the \"wobble\" the satellite experiences, and for the fact that gravity varies depending on where you a... | [
"Disclaimer: IANAS",
"Gravitational force between two objects can be calculated with the equation F=G",
"m2*d",
"Mass of a satellite (for this example I will be using a medium-sized sattelite) is around 500. kg, the mass of the moon is 7.34767309*10",
" kilograms. These two masses differ by an order of magn... | [
"Ahh that makes complete sense. Also the word wobble explains the function of the gyroscopes very easily. Was just wondering as I was driving and thought of the tides, but there's a bit of a difference there with the equation when it comes to mass. The ocean's mass is just a little bit more than the mass of a sa... |
[
"Public Raw Data resources ?"
] | [
false
] | Hello /Askscience. This one may be weird, so bear with me. I am an visual artist and programmer who is working on an upcoming realtime performance video piece. Rather than make up bullshit scientific read outs, I would love to find some really great public, open resources of raw data and the like that I can incorporate... | [
"http://www.data.gov/",
"It has pointers to some science data, lots of other stuff to. Like the Foodborne Outbreak Online Database."
] | [
"Hey, thank you very much, I will take a look around :)"
] | [
"If you're interested in DNA or protein sequences (Look for files in FASTA format for simple text):",
"NCBI",
"Uniprot",
"3D protein structures (you'll need a special viewer to see .pdb files but there are plenty of free ones available like JMol): ",
"PDB",
"Here's a list with a ton of other databases onl... |
[
"Considering many people who have reported crossing over experience when dying then being brought back, is it possible that the \"After Life\" is simply another dimension that our \"soul\" or energy joins?"
] | [
false
] | null | [
"Hi tchron thank you for submitting to ",
"/r/Askscience",
".",
" Please add flair to your post. ",
"Your post will be removed permanently if flair is not added within one hour. You can flair this post by replying to this message with your flair choice. It must be an exact match to one of the followin... | [
"Thank you for your submission! Unfortunately, your submission has been removed for the following reason(s):",
"/r/AskScience",
"For more information regarding this and similar issues, please see our ",
"guidelines",
"guidelines",
"/r/AskScience",
"If you disagree with this decision, please send a messa... | [
"Thanks I will post to ",
"/r/personaltheories"
] |
[
"Is it possible to heat up carbonated water to boiling point, but still keep the fizziness?"
] | [
false
] | A bit of a silly one, but I've always wondered what fizzy tea/coffee would taste like so I tried boiling some carbonated water in a kettle. It was predictably totally flat afterwards, but was this due to the turbulence of the water inside the kettle or is it something that will happen regardless as more heat is added? | [
"The solubility of carbon dioxide in water decreases with temperature. You can go here and scroll down to see this (",
"http://www.engineeringtoolbox.com/gases-solubility-water-d_1148.html",
"). That is why your boiled soda water went flat.",
"There may be a way to keep the CO2 in solution by boiling it und... | [
"Unfortunately, you'd have to let it cool down while pressurized because if you opened the cooker while hot the CO2 would simply come out of solution as the pressure decreased. So if you did that you'd end up with fizzy cool water again in the end, making it a bit pointless."
] | [
"True, you could never enjoy your hot fizzy tea unless you were drinking it in a pressurized environment.",
"I wonder if there is a gas that has a higher solubility in water at near-boiling temperatures."
] |
[
"What's DEHP? Is my laundry bag going to kill me?"
] | [
false
] | I just bought a laundry bag. Then I noticed some text on the package ... "State of california proposition 65 warning: this product contains DEHP, a Phthalate Chemical, Lead and other chemicals known to the state of california to cause cancer, birth defects and other reproductive harm." So, is the manufacturer just cov... | [
"DEHP is potentially toxic but you're safe if you don't eat the bag. It's commonly used as a low-cost plasticiser so for things like a laundry bag it makes perfect sense. It has very low solubility in water so it's unlikely to ever transfer to your clothes in dangerous quantities."
] | [
"This only answers part of your question, but you should know that those notices are required for all sorts of things in California. Every parking garage has a sign that says \"This area contains chemicals known to the State of California to cause cancer, birth defects, or other reproductive harm.\" This is for com... | [
"Ah I see.",
"Ok thanks."
] |
[
"Can any detectable gravitational lensing occur during a total solar eclipse, or does the moon not have enough mass?"
] | [
false
] | null | [
"A solar eclipse is when the moon blocks out the sun. The reason this is a good time to look for light bending is because the sun is mostly blocked out. The noticeable bending is actually occurring around the sun, not the moon. The amount of bending depends on the mass of the lens object (the middle object) and ... | [
"Yes, but I believe OP is asking if there is a detectable deflection in the sun's light around the moon."
] | [
"Ah, in that case the light would be bent by an angle of roughly 10",
" arc seconds, which I believe is too small to be detected."
] |
[
"What would happen if all of the tectonic plates were \"fused\" together?"
] | [
false
] | [deleted] | [
"Assuming you somehow managed this, there is an underlying (pun intended) problem; the Earth is a hot body, with a flowing mantle. That means convection. Convection cells drive the movement of plates, and over a geological timescale you can't just stop that. So even if you sealed them up, new faults and fracture... | [
"We can't fuse the plates together. Period. The forces are too great and until the heat engine of Earth runs down (billions of years from now), the plates will continue to shift. "
] | [
"Well since this is askscience I will still attempt to answer. I would say that hypothetically, even if we managed to fuse all the plates together, it will likely just break somewhere else. The plate movement is to relieves the pressure build up from the heat engine of Earth. It can not just keep building up with n... |
[
"Considering how much fuel it takes to reach escape velocity, and how heavy fuel is, how the heck would a manned mission to Mars be able to bring enough fuel to get back home?"
] | [
false
] | null | [
"\"The humans...\"",
"What are you?"
] | [
"It may be possible to collect and refine the atmosphere of Mars to produce fuel, resulting in large savings. ",
"Robert Zubrin and the \"Mars Direct\" group have developed a detailed proposal for a mission along these lines. ",
"We start by sending an automated chemical processing plant to ... | [
"I think the trick is not having to carry all the fuel around everywhere you go. The humans could do something like what was done with the moon landings, where a module full of fuel would orbit Mars and just descend a lander to the surface. That lander would have enough fuel to land, take off, and rendezvous with t... |
[
"Is there any benefit from drinking alcohol?"
] | [
false
] | null | [
"You get drunk."
] | [
"Why? That is one of the largest benefits. People drink because they enjoy getting drunk."
] | [
"A quick google search brought these results: ",
"One",
"Two",
"Three"
] |
[
"Can corn get cancer?"
] | [
false
] | null | [
"Any reason you specifically asked about corn? I wondered if you had come across some corn smut, a fungal infection caused by Ustilago maydis. It can look a little cancerous.",
"http://www.art.com/products/p360993043-sa-i4012783/dayton-wild-corn-zea-mays-infected-with-corn-smut-ustilago-maydis.htm",
"http://e... | [
"Plants are fundamentally different from animals in their growth, development, and physiology. Because of this they do not get cancer in the same way that animals, and especially mammals do.",
"There are a number of organisms that can cause uncontrolled or abnormal ",
" cell division and expansion in plants (b... | [
"Still waiting on those pictures!",
"Maybe you could genetically engineer a strain of Ustilago that required some synthetic amino acid, and a strain of corn that made that amino acid. Then we could grow these \"truffles\" here in the USA."
] |
[
"How did MIT's trillion FPS camera capture a photon moving through a bottle?"
] | [
false
] | Unless I'm wrong about the fundamentals of cameras, they record photons hitting the lens. So if a photon is travel through the bottle, how did any light reach the lens? Unless they didn't use a conventional camera, I don't see how they did it. Can anyone shed any light on how they shot this video? | [
"There are tons of photons going through the bottle. That camera system, like any other, can only capture those that scattered towards the camera. But some of the photons travel farther through the bottle than others before scattering and that system has a high enough frame frame that you can watch it happening.",... | [
"It isn't a single photon which is traveling through the bottle, it is a small 'packet' of organised photons (a laser pulse). Some of the light (even with a laser) always diffuses, especially when it enters something heterogenous like a plastic bottle, and that small amount is directed to the camera by mirrors. The... | [
"Off the top of my head... (I read the article months ago and have a bad memory)",
"They have a laser that pulses very short durations, and a camera with the equivalent of a short exposure time. They take many pictures this way, getting random light-path locations illuminated in the different frames, then later, ... |
[
"If you observed light being emitted from a source which incrementally increased the wavelength by 1nm. When that light starts to transition from visible to UV light, would there be a specific wavelength where we would suddenly stop perceiving anything or would it be more of a gradual fading out?"
] | [
false
] | null | [
"Imagine a vertical line shifting right to left on ",
"this graph.",
" At some point only your short cones are going to be stimulated and the amount of stimulation will reduce as the wavelength decreases. It will look like one color gradually fading out."
] | [
"You are aware that basically you see the result of your hypothetical experiment every time you see sunlight refracted through a prism or even simply a rainbow?",
"Sunlight does contain UV, and whenever it gets split up in a prism, not only the visible part of the light fans out, but also the non-visible parts li... | [
"Or since the green and red cones are still slightly sensitive at those wavelengths, the perceived colour will not quite be constant."
] |
[
"Is it possible for a planet to orbit multiple suns?"
] | [
false
] | null | [
"Yes, a handful of such planets are known - the Wikipedia page on circumbinary planets includes a list: ",
"https://en.wikipedia.org/wiki/Circumbinary_planet"
] | [
"A planet can orbit two suns if its whole orbit is significantly beyond the two orbits of the suns. In this instance, the suns together orbit the barycenter of the solar system, and the planets far beyond can be treated as if orbiting a single star located at the barycenter and having the combined mass of the two s... | [
"To piggy back off of this Space Engine has multiple examples of this type of system. Very cool. "
] |
[
"Can you catalyze the aluminum - gallium - water reaction?"
] | [
false
] | I've read that the reaction is good at producing hydrogen, yet the limiting factor is that it produces it very slowly. Does anyone know of any research done into accelerating this reaction? | [
"The use of gallium itself is a means to increase the efficiency of the reaction between aluminium and water to produce hydrogen. It's there to prevent the formation of a passivating layer of Al2O3. More generally, there as been research into hydrogen production from aluminium/ water and even patents have been prod... | [
"Not that I know of sorry. It all seems to be aluminium alloys and hydroxide solutions all as a means to (physically) reduce the passivating oxide layer. There's loads of referenced articles in the report. I'd recommend doing a citation search for some of the prominent articles in each section. Google the reference... | [
"Do you know if any other reaction-promotion methods have been tried aside from the few listed in that report? It looks like they all yield pretty similar results in terms of H2 production."
] |
[
"When you are knocked unconscious are you in the same state as when you fall asleep?"
] | [
false
] | If you are knocked out, choked out, or faint, do you effectively fall asleep or is that state of unconscious in some way different from sleep? I was pondering this as I could not fall asleep and wondered if you could induce regular sleep through oxygen deprivation or something. Not something I would seriously consider ... | [
"No, it's not the same. Sleep is a complex neurological state that we've only recently begun to understand where, while there is no alert consciousness, the brain is still cycling through a series of neurological activity (the chief of which, at least as far as day to day relevance goes, is memory reorginization an... | [
"Just so you know, you lose zero, and I mean ZERO time while knocked out. It's why so many fighters seemed confused when they come to. It's like, hey I was just punching you two thousandths of a second ago, why am I looking at you from the mat??",
"The experienced fighters will recognize the confusion as the sign... | [
"That makes sense.Thanks!"
] |
[
"Understanding of language by a computer, couldn't we make it work through linguistics?"
] | [
false
] | Let's first define understanding of language. For me, if a computer can take X number of sentences and group them by some sort of similarity in nature of those statements, that's a first step towards understanding. So my point is -We understand a lot about the nature of sentence structure, and linguistics is pretty adv... | [
"There's a lot more to language that people realize. Assuming we're dealing with just text, parsing is only around 85% accuracy these days, maybe pushing 90%. Dealing with speech, etc. is far more complicated.",
"To make matters worse, there is no agreed-upon model of grammars -- there are a range of models some ... | [
"It's possible, and is being done, but is very difficult. Human languages are very complex grammatically, and words can have very different meanings depending on context. I did some work on computer knowledge representation for a class, and was pretty overwhelmed with how complex trying to get a computer to underst... | [
"There's a lot of stuff going on here. Let me hit some main points, go back to work, then come back later and answer some more.",
"We should probably start with your first paragraph. You think that a good approach to natural-language understanding is to group sentences according to \"some sort of similarity in na... |
[
"Has the study of modern genetics proven the common ancestor theory? Why do we assume \"life\" would only be created once?"
] | [
false
] | I know that we haven't found the common ancestor, but if there is one everything should share at least some part of the same genetic code, right? I'm curious how much we actually know about the genetic relationship between species and whether or not this gives us enough information to actually "prove" that there was a ... | [
"It's been mathematically demonstrated from genetic/protein sequence similarity across a large set of known sequences, that a single universal common ancestor to all life on earth (Archaea, Bacteria, Eukarya) is 10",
" times more probable than the closest competing theory.",
"Douglas L. Theobald (2010) ",
"\"... | [
"There's an incredible amount of evidence that suggest that all present day organisms descend from one common ancestor, or the LUCA (Last Universal Common Ancestor). All life forms currently alive on earth posses a number of traits that are common, and these include:",
"-Cells made out of phospholipids forming a... | [
"The name LUCA only need refer to the last common ancestor of all life we know of today. It is possible that, in the early portion of the Earth's history, soon after the formation of critical biomolecules became feasible, that many distinct populations of what we might call life cropped up. LUCA would only have to ... |
[
"Do injuries take significant amounts of calories?"
] | [
false
] | [deleted] | [
"Yes but it is situational. The injury severity will determine the amount of calories needed for repair. One example is that a second or third degree burn will require substantially more calories for all the metabolic activities required to repair the damaged tissue. Something of this nature can actually cause weig... | [
"Additionally, any injury that requires a rather large inflammatory response or regeneration of tissue will substantially increase metabolic rate in part due to the necessary synthesis of new structural proteins. "
] | [
"As a follow up question, does an injured person need to consume more protein? "
] |
[
"How do prokaryotes produce ATP if they lack organelles such as chloroplasts or mitochondria?"
] | [
false
] | How? | [
"Prokaryotes have their ATP synthesis machinery embedded in the cell membrane, instead of of the mitochondrial/thylakoid membrane which is the case for eukaryotes.",
"Prokaryotes such as anaerobic bacteria rely heavily on the first stages of glucose break down - deriving enough energy from the breaking and restru... | [
"Prokaryotes have membranes just like organelles do. Photosynthesis and oxidative phosphorylation occur by very similar mechanisms in prokaryotes as the mechanisms in organelles of eukaryotes with the whole cell membrane used as the insulator instead of organelle membranes. In fact, the similarity in these processe... | [
"Prokaryotes do in fact use the pyruvate by directing it through the lactic acid fermentation pathway, producing NAD+ which is needed in glycolysis."
] |
[
"Does listening to higher frequency sound damage one's hearing more than low frequencies, at the same decidel level?"
] | [
false
] | From personal experience it seems like higher frequencies seem to incur more buzzing and loss of hearing after longer durations of exposure. | [
"Once in a lecture Charlie Liberman (full prof there) commented on the tendency of the high frequency hair cells to lose function with aging (die off). He claimed that portion of the basilar membrane has the highest metabolic requirements, and therefore is most susceptible to aging. That is, high frequency hearing ... | [
"This is actually a bit complicated to explain, and I'll do my best (someone correct me if I screw up - I worked on the auditory system but my physics is weak). ",
"Higher frequency sounds contain a lot more energy than low frequency sounds of the same amplitude. Basically, more 'waves' of sound hit your ear with... | [
"Very interesting stuff. I'm going to use this as an excuse to keep listening to doom metal without ear plugs..."
] |
[
"Is bending metal always a destructive process?"
] | [
false
] | If you have a spoon, and bend it in the middle, back and forth, back and forth, it will eventually break. Do all refined metals follow this pattern? What's happening, at the molecular level, each time the spoon is bent? Is there a metal or metallic object that can be bent indefinitely? | [
"If you are talking about cases where the metal doesn't immediately spring back, then yes, bending causes fatigue and the metal will eventually break. Steel has an \"endurance limit\", a stress below which it can be loaded cyclically an infinite number of times without failing, but this is elastic, meaning that it ... | [
"No. This is dependent on temperature. Above a certain temperature the metals can be deformed without damage. Only when the material starts crystallize will damage occur. It just happens that this temperature is above room temperature for most metals."
] | [
"You can see from this Stress(force over cross sectional area)/Strain(deformation with respect to original length) curve that metals will deform elastically to a point (meaning they return to original shape.) That is the linear region of the curve. Permanent plastic deformation occurs when more force is applied b... |
[
"With trees being as abundant and relatively defenseless as they are, why are there so few animals that eat them?"
] | [
false
] | I can only think of a handful of animals of the top of my head that eat trees or their leaves. It seems like with such an abundant of food and so little competition for it, why don't more animals prey on trees? | [
"Well, depends on which parts. An abundance of animals are folivores (eating leaves) and nectar-feeders. If the question is why don't more creatures attack and eat the wood, then the short answer would be: cellulose. Very few creatures can readily digest it, and even of those animals that \"eat\" wood, most of t... | [
"Good answers above, but I wanted to point out a flaw in the OP's thought process. Flora is not defenseless. Tough to ingest and digest cellulose fibers limit what wants to eat plants. Many are toxic. Thorns, brambles, thistles, etc... has evolved to thwart attackers. Some plants just evolved to grow faster than t... | [
"Cellulose and lignin. Tree trunks are made mostly of cellulose and lignin, both are difficult to break down, let alone digest. Cellulose is a sugar polymer (like starch or chitin) with the connecting bonds between sugars designed to resist break down. Lignin is a very complex aromatic alcohol polymer which is even... |
[
"Would conventional human narcotics have any effect on a lobster?"
] | [
false
] | No, I am not planning to drug a lobster. But a recent conversation turned to lobsters and heroin, and this spurned my curiosity. Are humans and lobsters similar enough that something like LSD, marijuana, etc, would have a mind-altering effect on a lobster? If I can't get a direct answer, could some of you fine folks po... | [
"I don't know if anyone's ever done the experiments on a lobster, but in the mid 20th century ",
"Peter Witt did it with spiders",
", to some pretty interesting effects.",
"Spiders and lobsters are pretty distant (like 500 million years diverged), but humans and spiders are far more distant, so I'd imagine th... | [
"Thanks for your response!"
] | [
"Homemade drugs are often tested on livestock to determine general suitability. LSD is the one that comes to mind, but it would seem prudent for any budding drug manufacturer."
] |
[
"How do we know light speed is the universal speed limit? For example, if light moves differently in a gravitational field, we'd never be able to gather any data to the contrary on Earth."
] | [
false
] | This is something I've been wondering for a long time. However, most of what I can understand (which is written for popular audiences, since my grasp of physics is 2 semesters of college intro courses) when I read about it involves discussing the implications of the light speed limit - not necessarily how we know it. I... | [
"We only \"know\" in the sense that it hasn't been proven false yet.",
"The idea of ",
" being constant in all reference frames is a direct result of special relativity, and being constant in all frames implies an absolute speed limit in the universe. Thus far, no experiment has been performed that suggests sp... | [
"To add to ",
"/u/tskee2",
"'s latter point, scientists are also trying to break their own theories all the time. At least half of the work that theorists do is testing their own theories to make sure there is no situation where that theory would contradict observations or the fundamental assumptions made in th... | [
"... The idea of c being constant in all reference frames is a direct result of special relativity ...",
"That's a prediction from Faraday and Maxwell's work about 50 years earlier. Supposedly Einstein developed special relativity as a way to make electrodynamics observer independent."
] |
[
"How does natural selection remove a trait that no longer has a fitness benefit but is otherwise benign?"
] | [
false
] | I have a feeling it has something to do with the costs associated with the development of the trait (in that case the idea of a benign trait is probably false). if this is the case, I want to know specifically how that works. It would be helpful if someone could provide an example. Thanks! | [
"If the costs associated with the development of the trait are detrimental in some way, then it will be selected against. If it's truly benign and has no effect on fitness, there will be no selection for or against it. This is how you get ",
"vestigial",
" traits. "
] | [
"One example is if development of the trait has significant energy cost, then any mutation that eliminates that trait would allow the organism to spend that energy elsewhere (such as reproduction), which provides selective pressure against the trait."
] | [
"Natural selection is a mechanism of evolution through which a trait is favored if it provides a better chance to survive (or to reproduce) to its host. This way, if a trait does not have a fitness benefit anymore, then there are two possible outcomes. First, if the trait is not noxious and has nos effect on its h... |
[
"Gastroenterologists, does drinking water (or any other beverage) whilst eating slow down or impair digestion in any way?"
] | [
false
] | Is it possible for water to dilute the stomach acid ever so slightly and slow down the digestion process? I'm aware that water helps break down food inside our stomachs, but does it impair the digestive enzymes in any way? If not water, what about milk, orange juice or even alcohol? How much liquid would one need to co... | [
"I constantly hear this but have never seen any solid evidence in support. It's a load of BS. The same people who strongly advocate against drinking water also willingly eat huge bowls of watery soup without thinking twice. Many fruits and vegetables are also composed nearly entirely of water. It's one of those see... | [
"fresh milk is close to neutral, slightly acidic.",
"You can use it to get rid of some spicy flavors because of their fat solublity. milk doesn't really have a lot of fat, but its highly dispersed-> big surface and you can drink it easily"
] | [
"I doubt this \"enough\" amount of water is physiologically achievable"
] |
[
"Why is there inertia (resistance to change in motion) for an object traveling through the vacuum of space far from any massive celestial bodies?"
] | [
false
] | For example, I'm inside a spacecraft hurtling towards a distant solar system and I'm halfway there. While in the living quarters, I push off of one wall towards another wall. After the push, would the spacecraft be thrown off course, even if the mass of the craft is much larger? A larger mass means a larger inertia, ... | [
"A larger mass means a larger inertia, but how is this true without strong external gravitational forces?",
"Mass has two properties in the context of your question.",
"It has an intrinsic response to outside forces (F = ma)",
"It creates an attractive force on other objects (this is gravity)",
"You don't n... | [
"Near a celestial body, the craft could be slightly altered due to redistribution of mass, in much the same way that an aeroplane's course (or more typically, it's pitch/roll) can. (Except swap the change in aerodynamic profile with orbital mechanics.) ",
"Edit: When so far from a distant body, you'd just start i... | [
"Inertia and gravitation aren't the same thing. There is inertia ",
"because there is",
", and it doesn't rely on gravitation."
] |
[
"Is the sun's movement through the galaxy perpendicular to the planets' elliptical plane?"
] | [
false
] | I see this video often: I've always wondered if that model is accurate or if it's speculation. | [
"It's somewhat accurate, but the angle between the invariable plane (the plane of the planets) and the plane of our galaxy is about 60° - you can actually observe this on a dark night.",
"In the video, the angle seems to be represented closer to 90°.",
"Here's",
" a good article with some illustrations depict... | [
"I think calling the motion a vortex is a bit misleading. The planets have no preference for trailing behind the sun, they rotate around it in close to circular orbits. This video added artificial trails behind the planets that don't exist and make it look like the planets are being dragged along by the sun.",
"I... | [
"Related to the \"vortex\" thing: from the site linked in the Youtube description, the creator of that video appears to be a ",
"peddler of pseudoscientific woo",
"."
] |
[
"Will this circuit work? (picture inside) [Engineering]"
] | [
false
] | null | [
"That circuit would probably start a fire. ",
"You've created a short circuit. By giving the current a very low resistance path to follow it will bypass the light bulb. Because the resistance is very low, you will have a very high current which leads to a huge amount of energy given off. That energy will manifest... | [
"what if one made the resistance of the path higher, so it would flow to the light bulb instead?"
] | [
"Sure, you could add a resistor. Then some of the current would flow through the resistor and some through the lightbulb.",
"But then, why? A single loop from positive battery terminal to bulb to negative would work just fine. By adding a second path, you will kill your battery quicker."
] |
[
"Other than water, is there any other compound that does not obey thermal expansion?(Since water increases in volume when the temperature is decreased)"
] | [
false
] | null | [
"cold water is denser than warm water",
"To be fair, there ",
" a regime where that is not the case. The turnaround is at about 4",
" C. That effect means frozen lakes often have their bottom layers at that temperature all winter, since water any warmer or any cooler will rise to the top. That in turn mean... | [
"Water actually does obey the law of thermal expansion. What you have heard is that ice is less dense than liquid water, which is true. But cold water is denser than warm water, and super-hot steam is denser than regular steam.",
"What you meant to ask is there any other compounds whose solid state is less dense ... | [
"Yes",
"."
] |
[
"The science behind sawing large trees.."
] | [
false
] | ..especially the tall ones which are cut down for timber. How do they go about sawing them? Is there someway to calculate the centre of gravity or to judge the direction in which the tree would fall down? | [
"Just make a wedge cut in the side you want it to fall. This cut has to leave enough of the tree on the uncut side so the tree won't fall over or bind the blade. Then go around to the other side and cut through to the wedge."
] | [
"Yes. As does wind direction and ground slope, often you ideally want to drop trees so the fall to low ground (as down the hill is ultimately where it's all headed). ",
"The principal science used is gut feeling developed over years of tree felling, passed onto young fellers. ",
"Tree farming is often fully ... | [
"The way the cut is made on a large tree can determine how it falls.",
"Modern tree farms use a machine that grab hold of the tree, then a circular saw blade cuts the tree, then the claws twist around and drop the tree on the ground",
"http://www.youtube.com/watch?v=BytyCZRhaJU"
] |
[
"Would living next to a star of a different temperature than ours affect how we see colours?"
] | [
false
] | I understand that the reason stars appear a different colour is because of their temperature. So I was wondering how being on a planet that orbits a blue star or some other colour would affect how we see on that planet. Would the planet's atmosphere be more affecting instead of the star's light itself? Hope that make... | [
"It would affect the light spectrum and the light reflected by objects.",
"However, the human visual system is remarkably good at not letting you notice that your surroundings are illuminated by a source with a different spectrum.",
"You are able to identify the same colours by candlelight, lamplight in the mor... | [
"A \"blue star\" is not the same as a blue lightbulb.",
"A blue star merely means, that it is so hot that the spectral maximum is shifted towards blue. Just as a red star has a low(er) temperature (like a glowing iron). It still is blackbody radiation containing all the frequencies, while a blue lightbulb usually... | [
"Well, don't we all see differences when in a room illuminated by a green, blue or red lightbulb? I know that personally I have difficulties with certain colours in a green room."
] |
[
"Since Hawking Radiation increases as the mass of a black hole decreases, can't micro black holes be used as perfect mass-to-energy converters?"
] | [
false
] | Assume that a micro black-hole is somehow created by humanity and placed in orbit around one of the Earth-Sun Lagrangian points, and that we construct a Dyson-sphere-esque energy harvesting sphere around it. We know that black holes emit Hawking radiation, which as far as I understand is infrared radiation or heat. Thr... | [
"Interesting thoughts. However, have you considered what the size of your black hole would have to be? For a black hole of that mass you'll have a schwarzchild radius of roughly 10",
" m.",
"That is you'd have to pack 600 000 tons worth of matter into a volume 10",
" or so times smaller than a hydrogen atom. ... | [
"I dealt with relativistic mechanics for a long part of my education and even after dealing with so many numerical values, I've never encountered one which truly surprised me until your comment. ",
"600kT in a space 27 orders of magnitude smaller than a hydrogen atom. Wow. I can't even begin to fathom the pressur... | [
"To echo nomamsir:",
"There is also the issue of containment.... something with that much mass which is smaller than an atom will simply plunge to the center of the earth. (rebounding a bunch, but eventually coming to rest in the middle)",
"You could conceivably charge it and use electromagnets to contain it, b... |
[
"Is the nuclear core burning scene from HBO show \"Chernobyl\" realistic ?"
] | [
false
] | null | [
"Which aspect of it? The Chernobyl meltdown happened in real life. Do you mean just the visuals?"
] | [
"Yes the visuals"
] | [
"They’d seem like they’d be realistic to me. Just light and snow coming from the fire. The radiation itself isn’t something you’d be able to see."
] |
[
"Sphere/Tetrahedron equivalent of the tesseract?"
] | [
false
] | It is common knowledge of what the shadow of a 4-dimensional cube (the tesseract) looks like in a 3-dimensional space. However, I am curious as to what those for a sphere or a tetrahedron would look like. | [
"If you continue triangle->tetrahedron->4D, it's called a 5-cell and looks like this: ",
"http://en.wikipedia.org/wiki/File:5-cell.gif"
] | [
"The sphere is boring, it's the hyper-sphere ",
"http://en.wikipedia.org/wiki/Hypersphere",
" (just like the tesseract is called a hyper-cube)."
] | [
"It may have a boring name, but I'd hardly call S",
" boring."
] |
[
"Humans get turned on by porn. Do other animals get turned on by seeing sex?"
] | [
false
] | I might be answering my own question but I've always been genuinely curious: is it our human cognizance that makes us get turned on by porn, or is it more instinctive/animalistic? Is it that we are able to project ourselves into porn and imagine ourselves doing it that makes it a turn-on? Do other animals capable of le... | [
"Not commenting on why seeing porn turns people on, but it is believed that it turns on pandas. There's a lot of trouble getting pandas to mate in captivity and one of the ",
"most successful things to get them to do so has been by showing them videos of other pandas mating",
". However, at this point, there's ... | [
"In short: Monkeys have been shown to value pornographic material, but the question of whether they or other animals are physically aroused by sexual imagery is poorly studied and remains an open question.",
"A study by Platt, Khera and Deaner at Duke University (reported in ",
" and online here",
"[54]",
"... | [
"Veterinarians at the Chiang Mai Zoo in Thailand are still attempting it, but with few results. To quote one of the doctors ",
"from a recent article",
", \"[the panda] seems indifferent to the videos; he has no reaction to what he’s seeing on TV.\""
] |
[
"Does the moon have significantly different gravity depending on location?"
] | [
false
] | I was thinking about it, if you were on the moon at the closest point to earth, I would think earth's gravity would lessen the moon's pull. Similarly, if you were on the furthest point from the earth, the earth's pull would add to that of the moon. So, is my thinking correct or is there another factor I'm not accountin... | [
"The moon's gravity does vary by location, but not significantly. You can see from ",
"this map",
" that it varies by about 1 gal, which is a centimeter per second per second, which is about 0.6%. The Earth's gravity varies by about the same amount, proportionally."
] | [
"A combination of topography, local density, and overall moon shape. The one thing I'm not sure of is whether it's a \"true\" gravity map which would look like ",
"this",
" for the Earth, or an \"anomaly\" gravity map, which maps the difference of the measured to \"model\" gravity, which looks like ",
"this"... | [
"if you were on the moon at the closest point to earth, I would think earth's gravity would lessen the moon's pull. Similarly, if you were on the furthest point from the earth, the earth's pull would add to that of the moon.",
"Something like this does happen. It's called tidal forces, but it doesn't work exactly... |
[
"Why does the eye closest to my pillow water when I lay on my side?"
] | [
false
] | null | [
"Gravity, eyes always produce water. They just go to the lowest point."
] | [
"Your tear ducts are in the corner of your eye towards your nose, and your \"lower\" eye would have gravity pulling water away from the duct, so it doesn't drain into your nasal cavity as usual. Then I assume it just accumulates and spills out.\n",
"http://en.wikipedia.org/wiki/Nasolacrimal_duct"
] | [
"Wow, thanks. That makes perfect sense. I hadn't considered the position of the drainage duct."
] |
[
"How do egg-laying animals obtain passive immunity?"
] | [
false
] | Or do they even have any passive immunities? I roughly understand how internally gestating animals get immunity through the placenta and blood transfer, but I wasn't sure if there was an analogous structure inside eggs. | [
"It has to do with the animal's formation of the egg. When I get to work I will compound further with scientific texts. :)",
"Edit: Creepy smile because this is a cool question.",
"Edit 2: When forming the egg, the mother's antibodies enter the yolk, allowing for transfer of immunity."
] | [
"The immunity you're describing is 'active' rather than 'passive'. Passive doesn't mean 'passed' but rather inactive components of the immune system such as skin and mucous barriers rather than antibodies, which are 'active' and acquired from the parent through the placenta. Great question though, can't wait to see... | [
"I'm moreso referring to naturally acquired passive immunity, as in, the passive immunity defined as the transfer of active immunity between parent and offspring. I understand what you mean, though."
] |
[
"Trinary* stars?"
] | [
false
] | I was thinking.. Is it possible to have 3 stars orbiting each other? *i'm not sure if "trinary" is correct, but it's the best guess i have. :) | [
"It is possible (and \"trinary\" is a correct way of referring to them). In fact, the closest star system, Alpha Centauri is (EDIT: Probably but maybe not, it's hard to tell) a triple system. The two long-known stars, Alpha Centauri A and B, are in a closer orbit while a third star, Proxima Centauri, orbits the pai... | [
"Eh, not firmly it turns out, no. It's still possible it's in a hyperbolic orbit. It ",
"looks more likely to be bound than not",
". ",
"It's a harder question to answer than someone might think since the orbital periods (if bound) are so large. It's still uncertain whether the Magellanic Clouds are bound to ... | [
"Is it known if Proxima is bound to the other two?"
] |
[
"Sports car vs. Small car fuel economy"
] | [
false
] | A lot of sports cars are a similar weight to a small car (maybe a little bit heavier). So why would the fuel economy be so low (in mpg) in a sports car when there is a powerful engine doing little work, whereas in a small car with a small engine can get around 60mpg but the engine is working generally harder? | [
"It's more than just the engine - the transmission gearing is selected based on the rotational velocity (RPMs) at which the engine makes a needed amount of torque (work) to move forward (work is force x distance).",
"A sports car usually has lower gearing than an economy car. This is because high compression over... | [
"Top gear did a test in which a prius was raced as hard as possible, with an M3 following it.",
"Because of the performance difference the M3 barely had to do any work, and at the end of the test the prius consumed significantly more fuel.",
"With modern MPI and computer controlled everything, the car will only... | [
"Saying about the advancements, I guess that could be something like the cylinders being selective now? ie. not using all of them all the time.",
"Variable displacement, the technology you describe, isn't really implemented in sports cars (AFAIK, it's possible that some newer models do) because it's contradictory... |
[
"Are we 100% sure there are no undetected planets in our solar system?"
] | [
false
] | If so, how? Edit: Thanks a lot foe the answers guys!! Got what i wanted.. | [
"Planets are pretty easy to see, and their gravitational effects are easy to detect. Here's ",
"a video showing the discovery of asteroids",
" from 1980 to 2012. As you can see, we have little trouble finding tiny, dark asteroids, so you can imagine how easy it would be to find a planet."
] | [
"By definition of what a planet is, yes. Planet must be massive enough to be rounded by its own gravity, is not massive enough to cause thermonuclear fusion, and has cleared its neighbouring region of planetesimals. While there are many object still in the Kuiper belt that have not been discovered, none of them are... | [
"Are there any undiscovered planets left in the Solar system? The answer to this question is no and perhaps yes! If we are talking about planets as large as Jupiter or Saturn moving in nearly circular orbits with semimajor axes smaller than a few dozen thousand astronomical units, the answer is almost certainly neg... |
[
"Are inflammasomes present in non-myeloid cell lineages?"
] | [
false
] | For example, is the NLRP3 (or another) inflammasome at play in epithelial cells? Interstitial cells? Smooth muscle? Endothelium? | [
"Mostly myeloid, but epithelial cells for sure. I think most research has focused on inflammosone function in immune cells, for obvious reasons, but other cell lineages/types have been getting more attention recently, and it stands to reason that the inflammosome would be active in non-myleoids, especially where mi... | [
"Ahh... exactly what I needed, thanks!"
] | [
"No prob. I was intrigued when you mentioned smooth muscle, as I imagined inflammosomes of macrophages would stimulate foam cell formation and otherwise contribute to atherosclerosis. But this 2018 open access research paper in JAHA looked at primary human vascular smooth muscle cells, basically hitting them with l... |
[
"How do barometers measure altitude accurately when air pressure is constantly changing?"
] | [
false
] | Fitness watches or bike computers - probably some phones too - track altitude change via air pressure change, accurately enough down to the foot/metre. How can they do this when the air pressure is always changing. And how can they be accurate down to feet/ metres? | [
"If your question is how is this possible if there is a daily variation of the sea level pressure? Off from the 1013.25 average?",
"First, the pressure difference between different altitudes is (almost) absolute - so you can always easily measure the vertical speed. By tracking the difference you know by how many... | [
"Any decent barometer based altimeter will be adjustable to compensate for atmospheric pressure changes. So you tell it how high you are at the start of a day or trip, and hope the air pressure doesn’t change too much during the time you are away from a reference."
] | [
"Right. They can’t without calibration. ",
"I had a watch that did time and altitude and you had to calibrate the starting altitude (it would be close but would require some fine tuning). After that it was pretty accurate unless a storm rolled through."
] |
[
"Why would I need to know the specific gravity of a Loctite compound?"
] | [
false
] | [deleted] | [
"The full ",
"datasheet",
" is actually even more detailed and specifies the viscosity too. It looks like this particular adhesive is sold in large quantities for industrial applications also, not just to consumers. In industrial applications knowing specific gravity and viscosity can be important if the adhe... | [
"Bang on. Think of a manufacturer that uses Loctite to secure the screws on a product. Knowing the specific gravity and the thermodynamic properties of the compound will greatly simplify the job of the person who has to write the code for the dispenser's controller."
] | [
"I'm pretty embarrassed that I didn't think of this. I work in automotive manufacturing and use fasteners with various forms of thread-locker and anti-seize constantly. Obviously it's an automated process to apply the compound to the threads as they fly off of the supplier's line. Thank you both for your replies!"
... |
[
"Is entropy of formation always positive?"
] | [
false
] | null | [
"Not at all; any time a solid oxidizes (e.g., iron rusting), for example, you have oxygen gas turning into a solid. This results in a huge decrease in entropy."
] | [
"Sorry, I thought it was clear from the context (\"Is entropy of formation always positive?\") that I was referring to the entropy of the molecules participating in the formation reaction. Obviously the total entropy in the universe increases for any spontaneous process."
] | [
"I respectfully disagree with at least part of this answer, citing the second law of thermodynamics. Sure, oxygen's entropy decreases, but entropy overall increases, as rusting is a spontaneous exothermic reaction releasing heat, thus increasing disorder of the surrounding molecules."
] |
[
"Does Taylor's Theorem imply Fourier's Theorem?"
] | [
false
] | If all continuous functions can be represented by polynomials, and sin/cos are continuous, that implies every form of sin or cos has their own Taylor series. Does this mean that every function that has a Taylor series can be translated to a series of equivalent sines and cosines? | [
"It's unclear what you mean by \"Fourier's theorem\", since there really is no theorem by that name. I assume you mean the fact that a continuous function on a closed interval can be approximated uniformly by trigonometric polynomials (i.e., polynomials in sine and cosine). That theorem is emphatically ",
" impli... | [
"Fellow engineer. This statement:",
"continuous function in time domain <-> discrete in frequency domain",
"Is not true. The true statement is: \"",
" function in time <-> discrete function in frequency.\"",
"A simple counterexample is the guassian function, whose fourier transform is ",
"also a guassian"... | [
"THAT'S what I was thinking of, I knew part of what I said was right. I guess the signals we were looking at have all been periodic"
] |
[
"Why is it that when underwater you lose red light first?"
] | [
false
] | When diving as you go deeper you start to lose colour and red is the first colour you lose I was wondering why this was. | [
"Water absorbs light in the visible spectrum, though it takes a lot of water for a human to notice it. Red light is absorbed 100 times more than blue light.\nThe following chart shows water's absorption at different wavelengths of light. The rainbow band denotes the visible spectrum, and as you can see, absorption ... | [
"This. Also, it is thought that the reason we see the spectrum we do is because of the relative absorbance of light from the sea. The relative energy of the visible range (violet-deep red) is the highest among those that reach the earth. However, they do not correspond exactly to those wavelengths most animals can ... | [
"The energy levels which the electrons can take in the atom due to various quantum mechanical rules. It's the electrons that absorb the photons (they are only allowed certain energy levels), and the energy is inversely proportional to the wavelength. "
] |
[
"How does the heart know how fast (or slow) to beat?"
] | [
false
] | Is it caused by some kind of signal to the heart from the brain? How does the heart know to beat faster when I am running, and to beat slower when I am at rest? I can't fathom how this works in our bodies. To extend on the question if I may, does it work differently for other animals? | [
"Without going much into the details (because I lack the english vocabulary unfortunately), one part of your nervous system is called the \"autonomous nervous system\" and on this system you have the the \"sympathetic innervation\" and the \"parasympathic innervation\", both of those innervation come from your nerv... | [
"For exercice, if I remember correclty, one big thing is the modification of H+ and CO2 levels in the blood.\nThe more you exercice, the more you'll produce those, and your brain will understand that you're exercizing and will set of the ympathetical nervous system ."
] | [
"Correct. Voluntary movement means that more energy is being produced from glycolysis and oxidative phosphorylation, which requires oxygen. During this process, blood pH lowers because of acid by-product and CO2 production. Chemoreceptors in the aorta, the artery that carries oxygen-rich blood from the heart to the... |
[
"In the case of hypergiant stars like VY Canis Majoris, how meaningful are our estimates of their size?"
] | [
false
] | [deleted] | [
"If the star is close enough to us one can use ",
"parallax",
" to measure the ",
" to that star.",
"If I remember correctly, sizes of stars are typically estimated using stellar models (i.e. using computers to model the physics going on inside a star). These models are best for stars similar in mass to our... | [
"We can actually measure the size directly. Process explained ",
"here",
".",
"We use computer models and empirical relationships more to get the mass of stars for example main sequence stars have L ∝ M",
" . We have various relationships for various types of stars. We can also use ",
"spectral type",
"... | [
"If you are asking about directly measuring stellar diameters, this can be done with interferometry. If you mean measuring masses, this can be done independent of modeling by looking at binary systems. "
] |
[
"Is there a material that will float on a cloud without falling through?"
] | [
false
] | I'm thinking heavier than air - like coating a snowboard with an extremely hydrophobic material? | [
"No. An object that is heavier than air will sink. ",
"An object coated with hydrophobic materials, but which is heavier than water, will sink in water. "
] | [
"If you've ever been in fog, you've been in a cloud."
] | [
"Plummers!"
] |
[
"How do frogs survive in winter?"
] | [
false
] | [deleted] | [
"They dig. Go more than a few feet underground and it gets to where it doesn't ever really freeze all the way through. Most frogs in areas that freeze over will then hibernate the winter away."
] | [
"Yes. Though wood frogs are noteworthy for being able to survive being frozen solid."
] | [
"Frogs, or at least some of them, produce proteins that are generally called \"anti-freeze\" proteins, though the reality is that they're not preventing freezing, but rather are preventing the water in their cells from freezing into structures that would damage the cells. (Water typically freezes into needle like ... |
[
"Due to the two hemispheres of the brain processing different information, would being deaf in one ear affect the development of the corresponding part of the brain?"
] | [
false
] | [deleted] | [
"The two hemispheres of the brain don't process sound from each ear so much as they process sound coming from one side of the head or the other, which is not the same thing. The direction of sound needs to be computed from the information from the two ears.",
"It is known that there are changes in how the brain ... | [
"\"Stunted\" is not the right way to put it at all. The brain is really good at adapting to whatever information it has available. Being deaf in one ear will absolutely change the information coming in to the system, so brain circuits that try and detect spatial information by comparing the input of both ears would... | [
"Probably not much. Auditory cortex in each hemisphere receives input from both ears. Check out the red path in this picture: ",
"http://what-when-how.com/wp-content/uploads/2012/04/tmp15F73.jpg",
"Source site: ",
"http://what-when-how.com/neuroscience/auditory-and-vestibular-systems-sensory-system-part-2/"
] |
[
"How do electrical impulses in my brain create my waking consciousness?"
] | [
false
] | null | [
"The correct answer is \"We don't know\".",
"But it appears you are not satisfied with that answer, so let us do some expanding.",
"Before that though, it appears you are skeptical of the qualifications of the panelists, so ",
"this is me",
". As you can see, I have been an active neuroscientist for a decad... | [
"Do you not think in the very near future we could program a computer to ",
"pass that test",
"? Given that, your test does not work (if we run off the assumption that a computer program is not conscious... though perhaps it is, because of the problem outlined: you cannot tell with certainty if another entity i... | [
"And if a computer can pass my test then I'd say it is conscious.",
"Okay, then your admitting we have no way of studying consciousness, as we can recognize what it is and what it isn't. i.e. A philosophical zombie would pass your test but by definition is not conscious. Put another way, if you're saying anything... |
[
"How does surface morphology change a thin film's fermi energy?"
] | [
false
] | My education was nice enough to explain each independently in separate classrooms but now how they interrelate | [
"Stop trying to sound smart and just ask your damn question. No one here cares how smart you are (or aren't, or think you are)."
] | [
"Please elaborate. How would you go about and measure said Fermi energy? Is the film deposited or \"free standing\"?"
] | [
"Do you mean Fermi Level or Fermi Energy - you have both written here. "
] |
[
"If telomers get shorter with every split of a cell, doesn't this mean we can pretty accurately calculate when someone will die of old age?"
] | [
false
] | null | [
"The concept behind the question is an interesting one and the idea of predicting the lifespan of an individual based on biological indicators is indeed a popular research topic.",
"Long story short specifically for telomeres, the answer is \"not really\". Different cells divide at different speeds. Also, many ce... | [
"This was my first reaction. Old age is not all the cells in one organ going: \"I give up\" all at once. It's just whichever one degrades enough to insufficiently do its job first. Then you tend to get a cascade of organ failures as one organ not doing it's job puts more stress on all the others barely doing the... | [
"Also just years and years of use. Many of our body's basic metabolic processes can cause inflammation or damage tissues over time. Lots of delicate balances have to be upheld to keep your body's own chemicals from causing damage. Throughout a lifetime, these balances are thrown off by all sorts of things--Illness,... |
[
"Does the moon (tides) make the earth a more suitable planet for life?"
] | [
false
] | Do the tides and such give life an evolutionary advantage at all? Would the earth be the same if there had never been a moon? | [
"The moon does a lot of things. Most importantly, it provides stability to our axis of rotation and I believe to our magnetic axis as well."
] | [
"I think that the slopes created by the tides allowed life to move to land. Without the tides, I bet it would have taken longer for organisms to develop tools to become terrestrial. The earliest organisms to trek on land (after plants), probably used limbs that were originally designed for gripping the land during ... | [
"This is probably the most important factor. Having a relatively large moon allows for a stable axis of rotation and therefore a more stable seasonal climate at most latitudes. Mars on the other hand does not have any large moon and therefore the axial tilt has oscillated widely throughout it's past, from 11-49 deg... |
[
"sqrt(2) squared creates an rational number from an irrational number; can something similar be done for pi? Are there any exponents of pi that are rational?"
] | [
false
] | Of course pi is 1, but are there any others? | [
"No non-zero rational exponent will do this, because pi is transcendental.",
"sqrt(2) is irrational but algebraic - that means there is a polynomial with rational coefficients to which sqrt(2) is the solution. Of course, the polynomial is x",
" - 2 = 0.",
"But pi is transcendental, which means it's not algeb... | [
"The notion you're getting at is that of ",
"algebraic numbers",
" -- numbers that you can take sums of powers of to get rational numbers. In other words, numbers that are a root of some polynomial with integer coefficients.",
"Numbers that aren't algebraic are called transcendental. π was ",
"proven to be ... | [
"The function f(x)=π",
" is continuous and its range is (0, ∞), so for any integer or rational number r you want, there's some z with f(z)=r. So there are infinitely many exponents of pi that are rational -- one for each rational number. In fact, given a rational number r, π",
"=r."
] |
[
"Why do certain liquors feel \"dry\" though they are liquids?"
] | [
false
] | Sake and gin come to mind when I think of dry liquors. The feeling is mainly textural. I suspect it may have to do with them numbing or not interacting with the tongue. | [
"The most common example of this is ",
"tannins",
" in red wine, which as the article says \"binds to and precipitates proteins and various other organic compounds including amino acids and alkaloids\". This precipitation of proteins in your saliva is what causes the textural change.",
"edit: This is the same... | [
"Sake is technically a Rice Beer by method of its production(brewing).",
"Brewing implies a conversion process from Starch-->Sugar--> Alcohol",
"Wine does Sugar-->Alcohol",
"Also Wine historically is fermented from naturally occuring yeasts on the grape skins, although cultured yeasts have been used since the... | [
"The term for that feeling, I believe, is astringent."
] |
[
"What causes the sensation of “wet”?"
] | [
false
] | I was working at my lab in my university, and was still wearing my gloves as I was washing some stuff. As soon as the water hit my hand I felt like I got wet, but when I took off my gloves my hands were completely dry - no water went through the glove to my skin. So this caused me to wonder what exactly happened that t... | [
"Both the cooling effect (temperature receptors) and the familiar feel of water (touch/pressure receptors)",
"The combination/pattern of sensations of both is very familiar to your brain and is interpreted as touching water/ liquid and getting wet"
] | [
"It’s mostly temperature, caused by the cooling effect of the water evaporating. Pretty much all volatile liquids (e.g. alcohol, acetone, gasoline) have a similar “wet” feel, whereas non-volatile liquids (e.g. vegetable oil) don’t have that same feeling."
] | [
"I'd say in the case he described it is mostly from the cooling effect of transduction, \"leading heat away\", not evaporation."
] |
[
"How does Newton's Cradle work?"
] | [
false
] | If 2 balls are dropped, 2 go up. Why doesnt 1 go up at twice as high? | [
"It's because KE=1/2mv",
", and p=mv. Both Kinetic Energy and momentum are transferred throughout the system and remain the same in an elastic collision (p and KE remain the same), and the interactions in a Newton's Cradle are pretty close to an elastic collision. ",
"So, if we put the equations through for 2-t... | [
"This is a good explanation, but I feel it is important to clarify that kinetic energy is conserved only in the actual collision- not the time when the balls are moving between collisions."
] | [
"I'm not sure, but it might be that the same two balls just bounce back up."
] |
[
"If Vitamin C is water soluble, why do vitamin-c tablets and products such as emergen-c recommend 2 servings per day? Shouldn't it not matter?"
] | [
false
] | [deleted] | [
"When it comes to water soluble vitamins, your body takes what it needs in the moment, and flushes the rest out of your system very quickly (usually through urine). (Have you ever taken a B-vitamin supplement and noticed that within a few hours your pee is very bright, almost neon yellow?) Taking the supplement twi... | [
"This is true, but, realistically, they recommend that you take Emergen-C twice a day so you buy twice as much. It doesn't hurt you because all the vitamins are water soluble."
] | [
"Ya, I thought about adding the fact that the dosages recommended are usually several times the recommended daily allowance, but thought that the real crux of the question had more to do with water solubility than corporate greed and marketing."
] |
[
"Why is the kilogram still defined to be the mass of a specific physical object? What has made it difficult to move away from this definition?"
] | [
false
] | The Wikipedia page for the kilogram says that it is the last SI unit defined in terms of an artifact. Why is this so? What has made it so difficult to redefine the kilogram? (I know that there are some problems with avoiding a circular definition -- many other units are defined in terms of the kilogram itself.) What ar... | [
"Why is this so? ",
"Because there wasn't a sufficiently good way to do it for a long time, plus some bureaucratic inertia. ",
"What has made it so difficult to redefine the kilogram? ",
"The circular definitions you noted, plus the need to define all the other constants in the measurement to equal or higher... | [
"There are two competing ideas. One is to specify it as a sphere of a certain number of atoms of a pure crystal lattice. You can measure dimensions of a sphere very accurately and if you know the lattice dimensions you can turn that into a number of atoms. However, to convert number of atoms to a mass you need A... | [
"See ",
"this article",
" in Wired about this very topic."
] |
[
"Why do the prongs on electrical plugs have holes in them?"
] | [
false
] | [deleted] | [
"Inside the outlet you plug the plug into, there are contacts that conduct the electricity into the plug, and those contacts have little bumps on them which seat into those holes on the prongs, and hold the plug in place more firmly."
] | [
"If you take apart an outlet, there are bumps on the contact wipers that the prongs slide into. They're there so the plug doesn't just slide out. Also sometimes the manufacturer of an electronic can run a \"seal\" like a plastic tag through one of the prong holes giving instructions to whoever's using it. They'll b... | [
"On top of regular outlets having little bumps to help lock into those holes, some 'locking' extension cords have a little lever on the socket end that slides pins through the holes of the plug that's plugged into it locking the two together. ",
"That way you aren't constantly unplugging your angle grinder as you... |
[
"Why do candle flames have pointed tips?"
] | [
false
] | Also, why is the tip the hottest part of the flame? | [
"Buoyancy effects. In plain English, heated air rises faster than the surrounding air. This effect tends to pull on the flame and cause it to narrow. At the same time the flame is running out of usable oxygen/fuel which causes combustion to cease. The tip is not necessarily the hottest part of the flame see this... | [
"You can make links by typing [displayed text goes here](address goes here). Also, it's best not to link to the result of a Google search. Use the actual image's address."
] | [
"Thanks! Still getting the hang of this reddit thing."
] |
[
"Why does ice stick to metal spoons?"
] | [
false
] | null | [
"It's not actually a chemistry effect but a physics one. Metal is a very good heat conductor which means it can change temperature very rapidly. What happens as you touch the spoon to the ice is that the warm spoon heats the ice up and a thin layer melts into water. But this removes the heat from the spoon. There's... | [
"This is why ice cream scoops are dipped in water between scoops, it warms the metal and un-freezes the ice cream on the next scoop.",
"If you try to scoop multiple scoops you'll freeze to the spoon on the second or third attempt. Depending on the thermal mass of the spoon and the temperature of the ice cream, i... | [
"Also why the best ice cream scoops like the Zeroll have a hollow handle filled with a conductive fluid to quickly move heat from your hand to the scoop and keep the scoop moving quickly through the ice cream."
] |
[
"What is the highest temperature that is tolerable to humans? What would happen if the air were near or above 100°C? How long would one survive at high temperatures?"
] | [
false
] | In extremely cold temperatures people will obviously not survive long without shelter or warmth. However, it is less clear what would happen at high temperatures. I remember reading somewhere that tests were done comparing human tolerance of heat to other animals, and it was discovered that humans' ability to sweat mad... | [
"211F = 99.4C",
"240F = 115.5C"
] | [
"High temperature, short exposure.",
"http://en.wikipedia.org/wiki/World_Sauna_Championships",
"The starting temperature in the men's competition was 110 °C (230 °F). Half a liter of water was poured on the stove every 30 seconds. ",
"2010 accident: two contestant died. The contest doesn't exist anymore.",
... | [
"The body produces a lot of heat from chemical processes, even when inactive. If the air humidity would be at a constant 100%, the body temperature would rise since the excess heat can't be ventilated through perspiration... Though it also says \"",
" experience lethal hypertermia\". Heavy physical activity would... |
[
"If dark matter has no electromagnetic interactions, does that mean it could move right through regular matter?"
] | [
false
] | My understanding is that the fact that I can't put my finger through a table is actually the result of electromagnetic interactions between the molecules of my finger and the molecules of the table. If dark matter has no electromagnetic interactions, does that mean it could "phase" through baryonic matter? | [
"Under most current ideas of what makes up dark matter, yes! Dark matter particles would interact only weakly (i.e. through the Weak Force) with normal matter, so they would seldom interact. Weakly Interacting Massive Particles (WIMPs) are probably the favorite idea for dark matter at the moment. Axions are another... | [
"Essentially, yes! And that's not strictly a property of dark matter, neutrinos also pass through ordinary matter without interacting."
] | [
"By current theories, dark matter in fact only interacts with other matter via gravity, and nothing else.",
"By ",
" current hypotheses, such as sterile neutrinos. Many of the current hypotheses include other interactions such as WIMPs which may interact via the weak interaction."
] |
[
"How does your body 'know' when to give you a fever?"
] | [
false
] | When you get a common cold, you don't get a fever. When you get the flu, you often do to kill the virus in your system. What determines whether your body goes into a fever or not and how does it know when to do it? | [
"The immune system produces many types of inflammatory mediators. One class of mediators is called Interleukins. Of these, IL-1 and IL-6 have an effect on the hypothalamus causing the body to reset the temperature higher. This is what causes fevers."
] | [
"The purpose of temperature in fever",
"World Immunology Congress",
"DECEMBER 14-15, 2017 DUBAI, UAE",
" K M Yacob\nMarma Health Centre, India\nKeynote: J Clin Cell Immunol",
"Abstract :",
"When the disease becomes threat to life or organs, blood circulation decreases, temperature in fever will emerges to... | [
"Is the increase in temperature also not to increase enzyme activity and denature viral proteins? I feel like there is more functionality to the fever other than the increased blood circulation"
] |
[
"How does salt damage concrete on a molecular level?"
] | [
false
] | Is it because it's corrosive? What makes "driveway safe" ice melting products, well, safer for the concrete? | [
"Normally the embedded steel in concrete (be it re-bar or welded wire fabric) is protected from corrosion by an effect called passivization caused by the high PH (around 13) of concrete. When water containing dissolved chlorides makes it way to the steel, through the concrete pore structure or more typically crack... | [
"Do not listen to this comment. Steel rebar is the perfect compliment to concrete construction. Steel is passivated in concrete. Steel has a well defined yield and the material properties are easily controlled. Steel also exhibits strain hardening and elongation, well past yielding, until ultimate failure. Why is t... | [
"Theoretically yes, if the temperature varied between 15 and 30 degrees F there could be additional freeze thaw cycles induced by the addition of de-icing salts. However, engineers have been compensating for freeze thaw damage for many years through the process of air entrainment.",
"A chemical admixture colloqu... |
[
"Why are so many dinosaur fossils found in the same contorted position?"
] | [
false
] | I know it's not always the case, but whenever I see a picture of land-based dinosaur fossils, they are almost always in . Is there a scientific reason for this contortion of the neck and tail, or is it just how the body was naturally moved and covered after death? | [
"Dinosaurs may not have had extended necks. Birds, for example, usually have curved necks, often with quite sharp turns. This fact is sometimes obscured by the feathers. ",
"So a dinosaur fossil showing an arched neck might actually represent the true position of that neck in real life.",
"A few googles found... | [
"I googled \"dinosaur fossil position\" and the second link was \"",
"Explaining the ”often” awkward positions of fossilized dinosaurs",
"\".",
"Veterinarian-turned-paleontologist Cynthia Marshall Faux has a new hypothesis to explain the ”often” awkward positions of fossilized dinosaurs. Faux and a colleague ... | [
"Interesting. It's also mentioned in ",
"Discover",
", and Here's a link to the ",
"actual paper",
" that describes this theory. Probably more impartial than a scriptural-based news hound."
] |
[
"To what degree are proteins usually able to remain functionally similar, as the number of different amino acids increases? 1? 20?"
] | [
false
] | As a secondary question, i know many drugs and compounds use similar molecules and not the exact same molecule to bind with similar receptors for an effect - what degree of error usually exists where specific shape matters? How similar in shape can different molecules be? What exactly does shape even mean at that level... | [
"It all depends on where the differences occur. ",
"The most important part of an enzyme (a catalytic protein) is called the active site, where the catalyzed reaction occurs. Sometimes, changing just one amino acid in the active site destroys the function of the enzyme. The rest of the enzyme is there to act a... | [
"I'm not exactly sure what you mean by your question but I'll have a go at tackling the second one.",
"The reason why different drugs can be used to bind the same receptor is due to the fact that the receptor is activated by specific ligand (activating molecule) shapes. Typically the parts of the ligand that acti... | [
"With reguards to the second question, many drugs bind to different receptors for a similar function because the drug is designed against a function/structural feature that receptors or kinases have in common. A classical example is the ATP binding pocket. Many receptor kinases and intracellular kinases utilize a s... |
[
"Why do some animals like dogs and cats live to be about 10-20 years, while other animals like turtles and parrots live about 100-200 years?"
] | [
false
] | null | [
"Within the parrots though, the trend still applies; larger parrots like macaws have much longer lifespans (80+ years) than smaller parrots and parakeets (10-20 years). But you're right, you'd expect very metabolically active birds to have shorter lifespans than similarly sized mammals based on this hypothesis; I'm... | [
"Within the parrots though, the trend still applies; larger parrots like macaws have much longer lifespans (80+ years) than smaller parrots and parakeets (10-20 years). But you're right, you'd expect very metabolically active birds to have shorter lifespans than similarly sized mammals based on this hypothesis; I'm... | [
"In general, smaller animals have faster metabolisms than larger animals. Higher metabolic rates lead to an increase in free radical production (harmful oxygens). These free radicals have long been associated with aging. So the gist of it is that smaller animals live faster and die younger. However, I'm not sure ho... |
[
"Can all our senses be fooled?"
] | [
false
] | I'm sure everyone is aware of optical illusions. And I know that auditory illusions, such as the Shepard tone, exist. Do similar illusions exist for taste, touch, and smell? And what about our other senses, such as nociception (pain); equilibrioception (balance); proprioception and kinaesthesia (joint motion and accele... | [
"taste",
"Put a few drops of orange food coloring in a glass of milk, and offer it to someone. Their reaction will be interesting, to say the least; it's possible that they may not even be able to identify the taste after drinking the whole glass. This is simply due to the incongruity between the taste that a per... | [
"For touch, yes. They're called tactile illusions: ",
"http://en.wikipedia.org/wiki/Tactile_illusion",
"Olfactory illusions, afaik, can be induced by giving visual/verbal cues that something tastes different than it actually does. So, for example, telling someone that this menthol scent is mint will make them p... | [
"This is because chili activates the sensory nerves through the same protein as heat does - it's called TRPV1. Similar story with mint/menthol: it activates cold-sensitive nerves through the cold receptor TRPM8."
] |
[
"How exactly do warm blooded species regulate their body temperature?"
] | [
false
] | From my understanding, warm blooded animals use food energy to regulate their body temperatures, while cold blooded animals maintain body temperature through gathering heat from outside sources. What biological function turns food energy into heat? How is it regulated? What do the cells/bodies/etc. of warm blooded anim... | [
"This is a really broad question. Don't think i could do it justice in a few paragraphs.",
"There are quite a few mechanisms animals use to either lose excess heat, slow down heat production, conserve heat in cold weather, and/or generate more heat if needed. ",
"I can answer a few specific questions.",
"What... | [
"That's a pretty solid answer. On the other side of it is: How does the body shed excess heat?",
"That, fortunately, is relatively straightforward. The circulatory system, along with transporting oxygen and other nutrients, transports heat. When you work up a sweat, the water you sweat out evaporates. The evapora... | [
"'cold blooded' and 'warm blooded' are somewhat archaic terms, and its not quite so simple. There are many different ways to regulate body temperature, and I don't think there's any species that has all of them.",
"To give a small answer as to how:",
"The ability to 'waste' chemical energy to produce heat throu... |
[
"Why isn't the atmosphere of Jupiter homogeneous?"
] | [
false
] | After what I would assume is a few billion years of mixing, why are there still such defined patterns in Jupiter's atmosphere? Why are the layers not homogeneous? Does it have to do with updrafts mixing more dense layers? | [
"Heavier gases tend to get to deeper layers, what you would expect with no activity is an equilibrium that doesn't have a homogeneous mixture, but heavier gases in deeper layers.",
"Jupiter's interior is still hot, while the outside is cooled by radiation (to space). In addition there is the \"daily\" cycle of su... | [
"Much similarly to how part of Earths atmosphere is white because of clouds, and part of it is transparent. No?",
"In other words, weather."
] | [
"Yes."
] |
[
"Why do light bulbs flicker at very fast rates?"
] | [
false
] | I know that lights flicker at speeds that the human eye can't perceive, but what I'm wondering is why they do this. Why isn't the light completely constant? If you look at high speed footage of a light bulb, as long as the frame rate of the camera is higher than the refresh rate of the light bulb, you will see the flic... | [
"HID lamps work by a different mechanism than ordinary incandescent light bulbs. In an incandescent light bulb, the current just heats some filament so that it gets really hot and glows. If there's a steady current the light bulb should glow steadily. In HID lamps, an electric arc is produced which generates the... | [
"I'm pretty sure that this is because the electric current supplied to them in ordinary light sockets is AC -- that is, the electric current oscillates at about 60 Hz (at least in the US)."
] | [
"Thanks for the response. I was watching an episode of Top Gear, and they had high-speed footage of two cars with their headlights on, and if you paused at different times you could clearly see the HID headlamps flicker. Would the current not be consistent with car headlights either?"
] |
[
"Are relativistic effects taken into consideration when measuring particle interactions?"
] | [
false
] | I know that the QM and GR are currently incompatible but specifically, is simultaneity of events an issue or concern when measuring particle interactions or properties such as momentum or position? Could it ultimately be the loss of simultaneity (GR) that prevents us from reconciling momentum and position simultaneous... | [
"Quantum mechanics and general relativity are incompatible, sure, but it's easy to include special relativity. In fact it's absolutely necessary for high-energy physics."
] | [
"is the reference frame of the particle the same as the reference frame of the object making the observation",
"Generally not, but this is not a problem. You can just do a lorentz transformation"
] | [
"\"Loss of simultaneity\" already happens in special relativity, which can be easily included in quantum field theory. Models like the Standard Model of Particle Physics obey special relativity.",
"The real problem is including gravity in quantum theory. There are multiple problematic parts, but the most obvious ... |
[
"If we could harness the daily energy from the sun with near 100% efficiency, would it be greater or less then the energy we use everyday?"
] | [
false
] | If there is far more energy provided by the sun than we use, what percent efficiency would meet our needs? | [
"A 100x100 mile block of solar panels with today's technology would provide enough energy for the entire united states. Provided there were no clouds."
] | [
"You mean the energy that hits the Earth? We'd need, roughly, ",
" .01% efficiency (assuming more or less current energy consumption).",
"Edit: stupid percentages."
] | [
"commenter's response makes me wonder if they understand the earth can only absorb the sunlight radiated to our fraction of the sky. I'm assuming the OP does not intend to harness the entire solid angle output of the sun, but only that reaching our little corner of the solar system."
] |
[
"how bad is BBQing with charwood for my lungs?"
] | [
false
] | i do this a lot. i have noticed that my phlem the next day is pretty black. obviously it is bad for me, but just how bad is it? is BBQing for half an hour as bad as smoking a cigarette? worse? less bad? are there any studies on long term effects of BBQing? | [
"Why are you breathing in the smoke off the grill? I'm confused...",
"In general though smoke has lots of nasty shit in like like polyaromatic hydrocarbons and all kinds of other transient reactive intermediates(including free radicals). fortunately our bodys our relatively decent at filtering out crap in the a... | [
"Why are you breathing in the smoke off the grill?",
"because i am right next to the grill, fanning the flames to make my food cook..."
] | [
"This is poorly described. Sir, are you smoking a BBQ grill?"
] |
[
"Will an object rotate in space if you apply a force away from it's center of gravity?"
] | [
false
] | [deleted] | [
"Yes it would rotate"
] | [
"...and so will you (due to the conservation of momentum)."
] | [
"if the direction vector of the force applied does not pass through the center of gravity rotation will occur. If the vector does pass through the center of gravity the body will move without rotation along the same vector.",
"If I read it correctly you are asking this",
"^ ........................................ |
[
"Lab Confessions: r/askscience what are some of your more ridiculous lab mishaps?"
] | [
false
] | [deleted] | [
"I cut into a minks anal gland once. It felt like being punched in the face. All my facial orifices instantly started running with tears, snot, saliva or whatever was in there. I was temporarily blinded. When I could see again I made it out into the hallway where people were already wondering what the hell happened... | [
"I've posted this before, and it's not so much a mishap as a glorious once-in-a-lifetime fuckup, but here goes:",
"I work in a lab that goes through a lot of rats. We only need the brains for our experiments, so we often share tissue we don't need with other labs.",
"One day, a cute girl comes in to collect the... | [
"I dropped my favorite pen in an emeritus professor's office and it rolled behind a stack of papers that was older than time itself. It is probably still there.",
"Edit: Maybe we need a ",
"/r/theoristproblems",
" akin to ",
"/r/firstworldproblems",
"."
] |
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