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i know this has been asked before, but i still can't wrap my head around it. minimum wage.	It's a complex issue and hard to study by it's nature, so nobody really knows if increasing the minimum wage is beneficial or not. Here's a ELI5 explanaition of both sides: Against Raising the minimum wage raises makes the profit margin for businesses with lots of minimum wage employees smaller since it raises th...	[ "A minimum wage is the lowest remuneration that employers can legally pay their workers—the price floor below which workers may not sell their labor. Most countries had introduced minimum wage legislation by the end of the 20th century. \n", "The minimum wage is the minimum wage required for human life and the ba...
up arrow notation like in graham's number.	When you multiply two numbers (m x n), you're really just adding m to itself n times. For example: * 4 x 3 = 4 + 4 + 4 = 12. The Knuth up-arrow notation was developed to make very large numbers easy to deal with. To get to Graham's number (3 ↑ ↑ ↑ ↑3), let's first look at what an exponent is. m^n is (just like multip...	[ "In mathematics, Knuth's up-arrow notation is a method of notation for very large integers, introduced by Donald Knuth in 1976. It is closely related to the Ackermann function and especially to the hyperoperation sequence. The idea is based on the fact that multiplication can be viewed as iterated addition and expo...
How did the British manage to mindbogglingly administer all the 500+ Princely States in India? What laws applied in these territories?	I will try to answer each of your question. #Question 1 * Most princely 'states' were states only in name. A city or a few clusture of villages was often what constituted a 'princely state' in many cases. So the 500 number is not actually as daunting as it seems * The British had a system called 'subsidary alliance ...	[ "By the beginning of the 20th century, relations between the British and the four largest states – Hyderabad, Mysore, Jammu and Kashmir, and Baroda – were directly under the control of the Governor-General of India, in the person of a British Resident. Two agencies, for Rajputana and Central India, oversaw twenty a...
Do black holes accelerate matter to light speed?	No. Massive objects always move slower than light. Also, talking about relative speed on objects that aren't in the same place doesn't generally make sense in general relativity. Usually it's not too bad, but black holes are kind of extreme. But you can still distinguish slower than light, light speed, and faster than ...	[ "Some of the best evidence for the presence of black holes is provided by the Doppler effect whereby light from nearby orbiting matter is red-shifted when receding and blue-shifted when advancing. For matter very close to a black hole the orbital speed must be comparable with the speed of light, so receding matter ...
why are car colors so dull?	Neutral colors are going to appeal to the widest audience. Bright colors can be found but they're the exception to the rule - most people tend to gravitate toward something more subdued.	[ "The most popular car colours today are greyscale colours, with over 70% of cars produced globally being white, black, grey or silver. Red, blue and brown/beige cars range between 6% and 9% each, while all other colours amount to less than 5%.\n", "The use of these colours in retro-reflective material is controll...
How did painters react to the invention of photography? Did they oppose it or did they embrace it as an emerging art?	Follow-up question: Did the increasing quality and affordability of photography in the late 1800s help popularize Impressionism, since it purposefully didn't attempt to realistically recreate landscapes?	[ "The invention of photography had a major impact on painting. In the decades after the first photograph was produced in 1829, photographic processes improved and became more widely practiced, depriving painting of much of its historic purpose to provide an accurate record of the observable world. A series of art mo...
why are asians discriminated against in college admissions, and how extensively are they put to a disadvantage? also, why are people okay with putting asians at a disadvantage, but not african-americans or hispanics?	Asians make up around 6% of the US population but account for 20 - 40% of college students in America. As a result Asians are vastly over represented in Universities and thus don't need protection like other minorities which tend to be under represented. Many people look at how well Asians are doing in getting into u...	[ "Aside from corporate underrepresentation, there is also a bias against students applying to colleges; there seems to be a racial quota established in several schools that limits its enrollment of Asian-American applicants. This existing bias is explained by professor of Public Policy at University of California Ri...
how does something like the james webb space telescope cost $8 billion?	Who made it? A huge team of NASA engineers working for years and years to develop technology never seen before. These are real smart dudes who don't work for chump change.	[ "The James Webb Space Telescope is a planned international 21st century space observatory. It is intended to be a premier observatory of the 2020s, combining the largest mirror yet on a near-infrared space telescope with a suite of technologically advanced instruments from around the world. JWST is expected to cost...
How long is a nuclear ground zero uninhabitable?	Standard thermonuclear weapons have a fallout that will typically degrade to habitable levels within 6-18 months. A ground detonation would produce a more severely affected local area of irradiation whereas an air burst would ultimately cover such a broad area that it would be diffused and relatively harmless. Af...	[ "Ground zero describes the point on the Earth's surface closest to a nuclear detonation. In the case of an explosion above the ground, ground zero refers to the point on the ground directly below the nuclear detonation. \n", "In terms of nuclear explosions and other large bombs, the term \"ground zero\" (also kno...
How did people do their taxes before computers were invented?	No scholarly links or background here but a first hand account of someone that was around in the bad old days of tax before computerized submission. You got a form, you filled it in. There were instruction booklets of various degrees of helpfulness & help lines you could call. If paperwork wasn't your thing, we...	[ "By the end of the Second World War, the IRS was handling sixty million tax returns each year, using a combination of mechanical desk calculators, accounting machines, and pencil and paper forms. In 1948 punch card equipment was used. The first trial of a computer system for income tax processing was in 1955, when ...
if evolution promotes survival, why do living things die naturally	Evolution promotes survival of the species, not of individual organisms. If anything, a species being immortal would be an evolutionary disadvantage as you are guaranteed to run into overpopulation and the subsequent exhaustion of resources.	[ "Contemporary evolutionary theory sees death as an important part of the process of natural selection. It is considered that organisms less adapted to their environment are more likely to die having produced fewer offspring, thereby reducing their contribution to the gene pool. Their genes are thus eventually bred ...
how does my dog have a habitual schedule daily but doesn't understand time? everyday he knows when his dinner should be made by messing with his bowl or making noises around 5 o'clock. but can't tell the difference between 3 days or 3 hours?	Just as animals in the wild having sleeping, eating, and mating schedules, so does your dog. He knows about the time he supposed to be fed. Or maybe he just tells you when he is hungry. My dog will whine if I forget to feed him in the mornings, which is rare, but he still knows he wants to be fed. He has a concept of t...	[ "The Dog Team had an unusual system of serving. Upon arriving at the restaurant, the menu was presented on a board just inside the entrance way. Customers gave their names and orders at that time, and went inside the building to wait. Waiting times of an hour or more were not uncommon during busy times.\n", "87. ...
differnt blood types and their impact.	Human blood falls into the catgories of A, B, AB, and O depending on the presence of certain markers on the red blood cells known as antigens. These antigens allow the body to recognize and distinguish its own cells form foreign red blood cells as part of our immune system. This occurs as each antibody is grouped wi...	[ "substances on the surface of red blood cells, and an individual's blood type is one of many possible combinations of blood-group antigens. Across the 36 blood group systems, 308 different blood-group antigens have been found. Almost always, an individual has the same blood group for life, but very rarely an indivi...
What was the extent of the Scots-Irish influence on the Blues?	I'm not certain that this is what you're looking for, but if you're referring to the type of blues that originated in the Mississippi River area (Delta, Chicago, etc.), they were at least minimally influenced by what's called "old time" music. Old time music is more or less what people today think of when they hear "b...	[ "The Blues went in yet another direction, when it started to mingle with Celtic and Scottish/Irish influences, forming still another hybrid. The general feeling of sadness, loss and blues, which is inherent in the Scottish, Irish and Celtic roots anyway, together with an all new instrumentation could lay the basis ...
What prevents a chimera's immune system from rejecting organs that developed from the other cell?	I'll refer you to [an earlier comment](_URL_0_) on this same topic, because I think the explanation is smashing. I'd also like to emphasize looking further into the role of regulatory T-cells if this kind of research is of interest to you, because they're still a mysterious power in the human immune system. For the s...	[ "A proposed strategy to avoid cellular rejection is to induce donor non-responsiveness using hematopoietic chimerism. Donor stem cells are introduced into the bone marrow of the recipient, where they coexist with the recipient’s stem cells. The bone marrow stem cells give rise to cells of all hematopoietic lineages...
What causes the opposite effects of size < -- > speed in gel-electrophoresis and size exclusion chromatography?	Watch these quick animations - should clear things up... (Pulsed-field) Gel electrophoresis (PFGE): [_URL_0_](_URL_0_) & #x200B; Size exclusion chromatography (SEC): [_URL_1_](_URL_1_) & #x200B; In gel electrophoresis you're forcing all the molecules to go through the same (continuous) matrix (gel) by applyi...	[ "Diffusiophoresis, by definition, moves colloidal particles, and so the applications of diffusiophoresis are to situations where we want to move colloidal particles. Colloidal particles are typically between 10 nanometres and a few micrometres in size. Simple diffusion of colloids is fast on lengthscales of a few m...
How much of "the final solution" did German citizens and soldiers know about?	Part 1 > Most of them were just soldiers fighting a war they didnt wanna be in, right? Not really. It's a fair assertion to say that virtually all Wehrmacht soldiers were aware of the atrocities that were committed, participated on some level in these atrocities and viewed most of it as legitimate. I have pre...	[ "On January 20, 1942, 15 high-ranking Nazi Party and German government officials met at a villa in Wannsee, a Berlin suburb, to coordinate the execution of the \"Final Solution\" (Endlösung) of the Jewish Question. At this Wannsee Conference, Reinhard Heydrich, Heinrich Himmler's deputy and head of the Reichssicher...
What motivated the kamikaze?	By 1944 when kamikaze planes began to be used the Japanese defence ring had fallen apart and the Japanese began to understand that the only way out of the war was to inflict as many casualties upon the Americans as possible, in vain hope that the American public would grow war weary and force their government to sue fo...	[ "While it is commonly perceived that volunteers signed up in droves for \"kamikaze\" missions, it has also been contended that there was extensive coercion and peer pressure involved in recruiting soldiers for the sacrifice. Their motivations in \"volunteering\" were complex and not simply about patriotism or bring...
During WW2, were prisoners sent to war or did they continue their sentence?	Not to discourage further responses, but I answered a question some time ago [here](_URL_0_) that I'll repost below.	[ "In 1950, after most Allied war crimes trials had ended, thousands of convicted war criminals sat in prisons across Asia and Europe, detained in the countries where they had been convicted. Some executions had not yet been carried out, as Allied courts agreed to reexamine their verdicts. Sentences were reduced in s...
Research questions regarding historic US census data	Here's tip - call them. On three separate occasions, I have had to call the Census Bureau for information and on each occasion they have been incredibly helpful. I can say the same thing about the DOE. It almost makes you feel good about the government.	[ "The National Historical Geographic Information System (NHGIS) is a historical GIS project to create and freely disseminate a database incorporating all available aggregate census information for the United States between 1790 and 2010. The project has created one of the largest collections in the world of statisti...
How close is the Earth right now in its orbit as it was exactly one year ago? (In relation to the Sun)	(Assuming that by "year," you mean at midnight on 12/31 last year). Well, the period that it takes Earth to orbit the sun is about 365.2564 days; since this was a leap year, this is a difference of about .7436 days. So we've gone .7436/365.2564 = .002036 extra orbits around the sun. Now the distance to the sun is 149...	[ "Earth orbits the Sun at an average distance of 149.60 million km (92.96 million mi), and one complete orbit takes days (1 sidereal year), during which time Earth has traveled 940 million km (584 million mi). Earth's orbit has an eccentricity of 0.0167. Since the Sun constitutes 99.76% of the mass of the Sun–Earth...
What are some good books regarding the transfer of Hong Kong?	Not a historian, but I did some historical economic analysis of Hong Kong under the British. I found these to be some useful sources. Not all of them cover modern history, but they're all comprehensive. * A DOCUMENTARY HISTORY OF HONG KONG, GOVERNMENT AND POLITICS STEVE TSANG (HONG KONG UNIVERSITY PRESS) ISBN 9622093...	[ "On television, Patterson presented a documentary about the transfer of sovereignty over Hong Kong, entitled \"Sir Les and the Great Chinese Takeaway\" (1997). He has appeared as a special guest on the following:\n", "In the Joint Declaration, the People's Republic of China Government stated that it had decided t...
How do birds know to make nests? Is it purely instinctual or is it taught?	It's both instinctive and learned, as with many complex behaviors. There's a review paper here, which is open-access and worth the read: > It is possible that a bird comes into the world with a template that provides the basic information as to what a nest should be like and how it should be constructed, but uses fe...	[ "Many birds (and other animals) build nests. It can be argued that this behaviour constitutes tool use according to the definitions given above; the birds \"carry objects (twigs, leaves) for future use\", the shape of the formed nest prevents the eggs from rolling away and thereby \"extends the physical influence r...
On average, how religious were the American founders, compared to average Americans?	They were clearly courting liberal positions for their era. They were far more educated the the average American so had ethical outlooks beyond religious books. The concept of 'Life, Liberty and the pursuit of Happiness' simply flew in the face of the religious establisment. Persuing happiness was proposed by Englishm...	[ "According to a 2002 survey by the Pew Research Center, nearly 6 in 10 Americans said that religion plays an important role in their lives, compared to 33% in Great Britain, 27% in Italy, 21% in Germany, 12% in Japan, and 11% in France. The survey report stated that the results showed America having a greater simil...
how are we able to make decisions if everything follows the laws of physics	The idea of free will is sort of up for debate in my mind. If our thoughts, and therefore our decisions, are nothing but complex chemical signals in the brain, then they were predetermined by the thoughts that came before them, and before those, and the chemistry that happened in the womb to form the brain and the firs...	[ "Other areas of decision theory are concerned with decisions that are difficult simply because of their complexity, or the complexity of the organization that has to make them. Individuals making decisions may be limited in resources or are boundedly rational (have finite time or intelligence); in such cases the is...
why would there be a primary within the same party of the incumbent president seeking a 2nd term?	Cause maybe the party doesn't want the incumbent again or believes someone else has a better shot of winning.	[ "Including the special election in Arizona, Republicans will be defending 22 seats in 2020, while the Democratic Party will be defending 12 seats. Because the vice president of the United States has the power to break ties in the Senate, a Senate majority requires either 51 Senate seats without control of the vice ...
Looking for some advice pertaining to teaching the Armenian Genocide.	As far as resources go, although it is a work in progress, a revamping of the WWI section of the booklist has been in the works recently, and the following are suggestions made by /u/yodatsracist and I which will at some point in the future be included, so this is a sneak peak. *The Armenian Genocide: Evidence From th...	[ "Kevorkian is the author of \"The Armenian Genocide: A Complete History\", \"an exhaustive and authoritative account of the origins, events, and consequences of the Armenian Genocide\". It was originally published in French in 2006. The book is the first to make extensive use of the archives of the Nubarian Library...
How did people deal with mold on food before refrigerators in different time periods??	First of all, while the refrigerator certainly did help, people used other means to cool food and keep food stored for long times. Ice coolers, where you would keep a block of ice in sawdust and have it replaced as it slowly thawed created cool spaces for the storage of food in Nordic countries' cities for a long time....	[ "Prevention of mold exposure from food is generally to consume food that has no mold growths on it. Also, mold growth in the first place can be prevented by the same concept of mold growth, assessment, and remediation that prevents air exposure. In addition, it is especially useful to clean the inside of the refrig...
What was the transition like from the Hapsburgs to the Bourbons in Spain?	In what sense? The actual transition between ruling dynasties was bloody and very messy: the War of Spanish Succession was fought between the major powers of Europe over whether a Bourbon - and, more importantly, Louis XIV's grandson - should be allowed to ascend to the Spanish throne. But are you talking about that wa...	[ "The prospect of Bourbons on both the French and Spanish thrones was resisted as creating an imbalance of power in Europe by its dominant regimes and, upon Charles II's death on 1 November 1700, a Grand Alliance of European nations united against Philip. This was known as the War of Spanish Succession. In the Treat...
Is Neil Armstrong's first foot print still on the Moon or have forces and events removed it?	> The biggest question for me that I do not have the answer is how careful were the astronauts when leaving and re-entering the Eagle lunar lander to make sure that Neil Armstrong's first footprint was not damaged. They weren't careful at all. The first footprint was likely obliterated within minutes of it being made...	[ "On August 25, 2012, the BottomLine was used to acknowledge the death of astronaut Neil Armstrong, the first man to walk on the moon. It was reportedly only the fifth of six times that an outside news event not involving an athlete was reported on the ticker, alongside the news of the September 11 attacks, the deat...
who invented the thumbs up compliment? and how long has it been around?	One popular explanation is that during the height of the Roman empire, Gladiators would turn to the guests of honor on whether or whether not to kill their opponents or beasts. The thumbs-up, or thumbs-down would symbolize the weapon coming down, or staying above the defeated combatant's head. Also, it also comes fr...	[ "The \"Oxford English Dictionary\" cites the earliest written instance of \"thumbs-up\" (with a positive meaning) as being from \"Over the Top\", a 1917 book written by Arthur Guy Empey. Empey was an American who served in the British armed forces during World War I. He wrote: \"Thumbs up, Tommy’s expression which ...
If the fluoride in toothpaste helps teeth by contact, how does the fluoride in water help if it only briefly comes in contact?	The fluoride in water is incorporated into the developing teeth of children and makes the enamel stronger and more resistant to decay. The fluoride in toothpaste works on contact to help remineralize weak areas.	[ "Fluoride is a natural mineral that naturally occurs throughout the world – it is also the active ingredient of many toothpastes specifically for its remineralizing effects on enamel, often repairing the tooth surface and reducing the risk of caries.\n", "Despite fluoridation's detractors, most dental professiona...
why do credit cards give airline miles?	The biggest credit card spenders are business travelers with expense accounts. That expensive business class ticket? They buy it. $15 hotel wifi? No problem. Expensive meal at a restaurant? Bring it on. They spend all that money on their credit card, and the company reimburses them for it. Plus they get to keep any air...	[ "Western officials traced the problem to difficulties with credit card payments. The company had been running into problems obtaining a merchant identification number, which was needed before banks would deposit money into the airline's account. The airline stated it was working out an arrangement with PayPal, whic...
how do doorbells work?	So traditional wired doorbells are normally simply a complete wired circuit involving: - a bell - a transformer to lower the voltage so that if the button gets compromised people won’t get a high voltage shock by pressing the button - a button outside - and wiring connecting it all When you press the button outside it...	[ "A doorbell is a signaling device typically placed near a door to a building's entrance. When a visitor presses a button the bell rings inside the building, alerting the occupant to the presence of the visitor. Although the first doorbells were mechanical, activated by pulling a cord, modern doorbells are electric,...
Monday Methods: History Pedagogy (The Theory and Practice of Teaching and Learning)	Great work! I particularly appreciate the section on the obsession with "coverage." Too many times have I seen educators at both HS and collegiate level get obsessed with teaching it all (as if possible). I always suggest the method of creating your class topics last in developing your course structure. Start with yo...	[ "Critical pedagogy explores the dialogic relationships between teaching and learning. Its proponents claim that it is a continuous process of what they call \"unlearning\", \"learning\", and \"relearning\", \"reflection\", \"evaluation\", and the effect that these actions have on the students, in particular student...
are there any disorders that involve an altered perception of the rate of time?	[This might interest you.](_URL_0_) I know at the least some disorders cause you to "lose" time in the sense that you blacked out and can't remember what you did. I'm just adding useless text to my comment here because for some reason this sub thinks you cannot give a concise and meaningful answer. Must have long win...	[ "Along with other perceptual abnormalities, it has been noted by psychologists that schizophrenia patients have an altered sense of time. This was first described in psychology by Minkowski in 1927. Many schizophrenic patients stop perceiving time as a flow of causally linked events. It has been suggested that ther...
how does a full cycle charge extend a lithium-ion batteries life?	It's not required for the battery at all. You know how the battery meter on your phone or whatever says 100% right when you take it off? And 57% sometime later? It needs to be calibrated to accurately determine from the battery (usually via a voltage measurement) what the state of charge is. Doing a full cycle ...	[ "Battery cycle life is most commonly specified at a discharge depth of 80 percent of rated capacity and assuming a one-hour discharge current rate. As the discharge current or the depth of discharge is reduced, the number of charge-discharge cycles for a battery increases. When comparing NiZn to other battery techn...
Which interactions can explain that EtOH (Alcohol) has a way lower freezing point than H2O?	The same exact processes apply. The way you should look at it when compared to the boiling point is seeing the freezing point as a melting point instead. Just like water has a higher boiling point than ethanol, it also has a higher melting point.	[ "As a derivative of methanol, triphenylmethanol is expected to have a p\"K\" in the range of 16-19. Typical of alcohols, resonance offers no stabilization of the conjugate base due to being bonded to a saturated carbon atom. Stabilization of the anion by solvation forces is largely ineffective due to the steric inf...
What's going to happen to the polar bears as the ice caps shrink? Evolution or extinction?	Well extinction is a distinct possibility as a loss of sea ice results in very large evolutionary hurdles. On the other hand with less ice and snow, selection pressures favour darker bears, and as they can interbreed with grizzlies its possible they might just converge back into a single species.	[ "Four months later, the United States Geological Survey completed a year-long study which concluded in part that the floating Arctic sea ice will continue its rapid shrinkage over the next 50 years, consequently wiping out much of the polar bear habitat. The bears would disappear from Alaska, but would continue to ...
what is a scripting language?	A scripting language is a type of programming language, it's normally not compiled before being run and normally is created or modified by end-users. It also normally is used to interact with other applications, as opposed to creating an application itself.	[ "A scripting or script language is a programming language for a special run-time environment that automates the execution of tasks; the tasks could alternatively be executed one-by-one by a human operator. Scripting languages are often interpreted (rather than compiled).\n", "A scripting language is a high-level ...
If some tectonic plates are subducting under one another, is it possible for a whole landmass to be forced underneath when it reaches the boundary?	Subduction zones feature oceanic plates (usually old and cold oceanic plates) sinking into the mantle. I say "sinking" because that is literally what is going on. Oceanic plates are high density, especially when they are old and cold, and when they enter subduction zones they sink very slowly through the solid mantle...	[ "The theory of plate tectonics states that the Earth's crust is made up of rigid plates that \"float\" on top of the mantle and move relative to one another. As the plates move, the crust deforms dominantly along the plate margins. Intraplate deformation differs from that respect by the observation that deformation...
What sort of building materials might we fnd and utelize on mars?	The first intended use of in situ resources will be using water on Mars for human consumption and breathable air, along with separating the hydrogen and oxygen for fuel. For habitation we will start with units sent from Earth and use local materials for radiation shielding (as shells surrounding the prefab units for ...	[ "In situ resource utilization involves using materials encountered on Mars to produce materials needed. One idea for supporting a Mars habitat is to extract subterranean water, which with sufficient power could then be split into hydrogen and oxygen, with the intention of mixing the oxygen with nitrogen and argon f...
Looking for European history books written by non-Westerners. What's a good place to start?	This isn't exactly what you are looking for, but your question reminded me of the [Chinese fascination with Jews](_URL_0_). It is very interesting to see how an entirely foreign culture view a culture that is more familiar to us. It also makes you wonder how accurate and fair Western historians actually are when they t...	[ "The guidebooks have received much praise in the international media. The \"Wall Street Journal\" described the style as \"tongue-in-cheek advice\" with \"brutal honesty\". The \"International Herald Tribune\" described them as \"an Eastern European publishing phenomenon\" and \"The Times\" wrote that they are \"Th...
What makes certain stainless steels non-magnetic?	My metallurgy teacher would murder me for this answer, but here's the basics. Regular steels at normal temperatures exist in the crystalline state martensite. When heated above a temperature (which is defined by the alloying elements in the steel), the crystal structure breaks down, and the steel's structure beco...	[ "Stainless steels are used extensively in these industries for their corrosion resistance to both aqueous, gaseous and high temperature environments, their mechanical properties at all temperatures from cryogenic to the very high, and occasionally for other special physical properties.\n", "Stainless steels conta...
Can a Neutron star and a black hole be in the same star system?	It is possible, but none have been detected.	[ "Binary systems containing neutron stars often emit X-rays, which are emitted by hot gas as it falls towards the surface of the neutron star. The source of the gas is the companion star, the outer layers of which can be stripped off by the gravitational force of the neutron star if the two stars are sufficiently cl...
how are cancer and tumors related? does one cause another?	Tumors are cells that are ignoring only some of the rules the body sets for them. Cancer cells have gone completely renegade. Specifically, the body sets clear rules for which cells are allowed to divide (and thus grow their tissue) and when. That's how you grow and maintain your organs and other bodily tissues. If ce...	[ "A tumor is an abnormal growth of body tissue. In the beginning, tumors can be noncancerous, but if they become malignant, they are cancerous. In general, they appear when there is a problem with cellular division. Problems with the body's immune system can lead to tumors.\n", "This is a list of cancer types. Can...
why does metal shrink & water expand when they turn from a liquid to a solid?	Water molecules stick together through hydrogen bonding. In a liquid state, there is enough kinetic energy (heat) in the molecules to prevent stable hydrogen bonds from forming, so they form and break as molecules flow over each other. As water loses heat (remember, kinetic energy) they are able to move closer togeth...	[ "Most metals and alloys shrink as the material changes from a liquid state to a solid state. Therefore, if liquid material is not available to compensate for this shrinkage a \"shrinkage defect\" forms. When progressive solidification dominates over directional solidification a shrinkage defect will form.\n", "Ab...
how do micronutrients work? are they a good solution to malnutrition in poor countries?	Micronutrients refer to the nutritional value of a food, e.g. vitamins and minerals Macro nutrients refer to the nutritional content of food, e.g. Protein, carbohydrate and fat Micronutrients would help if the said person was deficient in vitamins due to a diet that isn't varied, however if the said person if defici...	[ "Nutrition International, formerly the Micronutrient Initiative (MI), is an international not for profit agency based in Canada that works to eliminate vitamin and mineral deficiencies in developing countries. Although often only required by the body in very small amounts, vitamin and minerals – also known as micro...
Is it possible for a dark object to be moved by a bright enough flash of light?	Yes, light has momentum. When light hits an object and is absorbed or reflected, under conservation of momentum the object has to gain some small amount of momentum. see also: - _URL_1_ - _URL_0_	[ "According to Prof Leonhardt, all optical illusions can slow down rays of light and the sphere can be used to bend this illusion around an object, reflecting off it and making it appear to be invisible. Mr Perczel added: \"When the light is bent it engulfs the object, much like water covering a rock sitting in a ri...
Is there an object that floats on moving water but sinks otherwhise?	Sure, if you count floating as staying at some constant level in the water. The floating wouldn't be caused by only buoyancy, it has to be some combination of buoyancy and lift. You can generate lift in water with hydrofoils.	[ "A floating object will seek the highest point of the membrane and thus will find its way to either the center or the edge. A similar argument explains why bubbles on surfaces attract each other: a single bubble raises the liquid level locally causing other bubbles in the area to be attracted to it. Dense objects, ...
- what exactly is the current relationship between the us and cuba, and why does it appear that the relations haven't changed much despite the end of the cold war?	When Castro came to power, may Cubans fled to Florida, and harbored a deep seated hatred for Castro, one they handed down to their children and grandchildren. So now there is this huge community of rabid anti-Castro voters living in the biggest swing state in the US. During the Cold War, this served US interests we...	[ "Over time, the United States' laws and foreign policy regarding Cuba has changed drastically due to strained relationship. Beginning with opposition to the Castro led Independence Revolution in Cuba, the Spanish–American War, naval use of Guantanamo Bay, trade restrictions imposed by Nixon, and a trade embargo ope...
If you're stuck in a fire, is it a good idea or a bad one to douse yourself with water?	I'm not a scientist - so I'm not sure if I'll be welcoming the downvote brigades - however, I am a certified Fire Fighter and Fire Safety Officer, so I can chip in with a bit of 'actually been inside a burning house' experience. Firstly, from a structural standpoint - the steam that comes from throwing water on a fire...	[ "Use of water in fire fighting should also take into account the hazards of a steam explosion, which may occur when water is used on very hot fires in confined spaces, and of a hydrogen explosion, when substances which react with water, such as certain metals or hot carbon such as coal, charcoal, or coke graphite, ...
when i call someone, why is the first ring always louder than subsequent rings?	This is probably due to sensory adaptation. When you experience something that triggers one of your senses multiple times in a row, the experience is less and less each time. This is also why you get used to smells.	[ "The ringing tone is often also called \"ringback tone\". However, in formal telecommunication specifications that originate in the Bell System in North America, ringback has a different definition. It is a signal used to recall either an operator or a customer at the originating end of an established telephone cal...
Are there Babylonian or Sumerian myths that could have inspired the myth of Moses, like how there are for Noah's Ark?	Sargon of Akkad was supposedly found in a basket in a Mesopotamian river. (Roux, Ancient Iraq)	[ "The Boatman of the title \"is Noah, but both Noah and the ark itself form an allegory for the artist and the artistic experience, the ark representing Jung's collective unconscious.\" \"The creation is inside its creator, and the ark similarly attempts to explain to Noah ... that it is really inside him, as Eve wa...
When did relations between Native Americans and white settler/travelers turn from friendly trade to violent outbursts?	Hello there. Unfortunately we have had to remove your question as it looks like it may be a homework question. A couple of things to keep in mind about this: [Our rules](_URL_0_) DO permit people to ask for help with their homework, so long as they are seeking clarification or resources, rather than the answer itself. ...	[ "Initially, there were peaceful interactions with Native Americans. Chiefs Washington and Colorow led their tribes along Sulphur Gulch, passing and sometimes visiting cabins of early settlers, like John and Elizabeth Tallman. During one visit, Chief Washington offered up to 20 ponies in trade for their red-headed s...
Help/suggestions on what books to read pertaining to ancient Syrian history.	Caveat: I am most familiar with the history of Syria prior to the Achaemenid period, and my reading recommendations reflect that. # HISTORICAL OVERVIEWS Ancient Syria: A Three Thousand Year History by Trevor Bryce is a good first introduction. Bryce relies too heavily on textual sources at the expense of archa...	[ "Syria, subtitled \"Archéologie, art et histoire\" (until 2005 \"Revue d’art oriental et d’archéologie\"), is a multidisciplinary and multilingual academic journal covering the Semitic Middle East from prehistory to the Islamic conquest. It is published by the Institut français du Proche-Orient and was established ...
why are certain eye colors almost none existent? (like purple)	Only time I have seen "red" is with albinos. You see red because of the complete absence of pigment which allows for a good reflection of their retina in the correct lighting conditions. This lack of pigment also means that they tend to be very sensitive to light (a lot of albinos are nearly blind). Eye color is mainl...	[ "The phenomenon is not entirely understood. One possible reason people see colors may be that the color receptors in the human eye respond at different rates to red, green, and blue. More specifically, the latencies of the center and the surrounding mechanisms differ for the different types of color-specific gangli...
Why were the religions in the British Isles so divided?	Firstly, Scotland is in Britain. On the map, England is marked as Anglican (and Wales isn't marked at all, but then, from a legal standpoint Henry VIII had made Wales part of "The Realm of England") Secondly... why shouldn't they be different? They were different countries, with different histories. Scotland and Engla...	[ "The predominant religious tradition of the island is Christianity. Before the Protestant Reformation, the island had a long history as part of the unified Western Church, and in the years following the Reformation, the religious authorities on the island, and later the population of the island, accepted the religi...
Happy 2nd Birthday, AskHistorians!	> Your favorite askhistorians moment Four words: April. Fools. Rule. Changes. That was fantastic.	[ "Happy Birthday was written and composed by Japanese Hip-hop artist SEAMO. \"Happy Birthday\" reached the number-one spot on both the daily and weekly Oricon charts, selling 201,304 copies in its first week; just 38 more copies than their previous single Summer Time, which sold 201,266 copies in its first week.\n",...
Why does something made of iron smell?	Iron is constantly oxidizing with oxygen it comes into contact with. It is vaporizing, but very slowly. It's why rust happens, and why rust is much less dense than iron; some of it has turned to gas. Almost the same thing happens with pennies, only with oils. You know that copper-y smell that pennies have? That's the...	[ "The study of odors is complicated by the complex chemistry taking place at the moment of a smell sensation. For example, iron-containing metallic objects are perceived to have a distinctive odor when touched, although iron's vapor pressure is negligible. According to a 2006 study, this smell is the result of aldeh...
what safety measures are on gas tanks to prevent them exploding when a car is on fire?	Usually seal them so oxygen cannot get to the gas and contribute. On a science note, gasoline vapor is explosive and flammable, not so much liquid gasoline. So as long as the gas is condensed into a liquid and kept contained, it's quite safe. Which is also why you should never take the nozzle out of the tank if there...	[ "The fire department was in the process of setting up a deluge gun to cool the car, which would have delivered far more water than the booster attack lines they initially were using; however, before the deluge gun could be made ready, the pressure inside the tank car reached the design bursting limit and the tank c...
When did the language of French become the majority language of France?	I cant speak on the validity of the 20% comment , however, french became the language of France during the French Revoloution. Before French borders became much more realized during the end of the 18th century, France was composed of french, flemish, german, italian, among other languages. By 1795, the national convent...	[ "In the modern era, there are several major loci of the French language, including Standard French (also known as Parisian French), Canadian French (including Quebec French and Acadian French), American French (for instance, Louisiana French), Haitian French, and African French.\n", "Until the early 20th century,...
why does white bread crisp quicker compared to brown bread when toasted?	It's made mostly from white bleached flour and is generally lighter in both appearance (so the toasted bits show up better) and density than most brown breads. The latter are generally coarser and heavier, and have more of the doesn't-burn-so-easily parts of the wheat grain in them like the grain's skin, particularly...	[ "White bread serves as the baseline of 100. In other words, foods scoring higher than 100 are more satisfying than white bread and those under 100 are less satisfying. The satiety score was negatively correlated to the amount eaten by participants at a subsequent buffet.\n", "Toasted bread slices may contain Benz...
my bird starts chirping when he hears other birds of completely different species. why?	Birds can only have offspring with their own species, so recognizing your own species is done through the specific songs. Birds are also quite territorial, not just for nest building but also for general food and water resources in the area, so singing is a great way for advertising that this is your area. So they're...	[ "This species is heard more often than seen, but its calls often help to locate it visually. To vocalize they move higher off the ground than during their usual activities, and may perch on an exposed site. They also nod their head and bow their body when calling, making them even conspicuous sometimes. Calls like ...
Why did camels never catch on as transport animals in the American West, as they did in almost every other desert/plains on earth?	Interestingly, both camelids and equines are native to North America - after having colonised Eurasia, both vanished from North America, most probably having been hunted to extinction after humans colonised the continent, roughly 8-10 000 years ago. HORSES: Horses returned in 1494, with the second expedition of Colum...	[ "The camels were used as pack animals, especially in the north, while in the south, camels were used to pull drays with supplies for the riders. Camels were ideal for this as they could go for a long time without water, and it has been suggested that the fence could not have been built or maintained without the use...
how come some vendors require my debit card pin but others do not?	Your debit card has Visa (or another credit card company) backing it. Each transaction can be run as debit (processed by your bank directly, requires your PIN) or credit (processed through Visa, does not require your PIN). Processing as credit through Visa is to your advantage as the consumer. The consumer protectio...	[ "Because the customers have to use a PIN code in the BankAxept system, but not with many other systems, it is also much more frequent that stolen debit cards are abused in card fraud with merchants that only have an agreement with the international payment systems and online.\n", "Chip and PIN systems can cause p...
why do stores display fruit and vegetables outside where people could steal them?	Other than street urchins and tykes, who is stealing apples from a store front?	[ "In addition to shoplifting, thievery also has been due to pilfering by shipping personnel and burglary. Book stores also are victimized by thefts of merchandise and other items aside from books. At Vroman's Bookstore in Pasadena, California, someone attempted to steal a security camera. At the Boulder Bookshop in ...
How do we know what is in the center of the Earth?	One way is from looking at p and s waves that travel through the earth when there is an earthquake. Direct observations of things come from looking at light, which is just a wave. So looking at waves that travel through the earth can then be used to probe deeper than our eyes could see. This can give you things like th...	[ "The geographical centre of Earth is the geometric centre of all land surfaces on Earth. In a more strict definition, it is the superficial barycenter of the mass distribution produced by treating each continent or island as a region of a thin shell of uniform density and approximating the geoid with a sphere. The ...
why do i need planning permission to build on land i already own?	So you've got this nice piece of land and you've spent your life saving building yourself the house of your dreams on it, then a company buys the piece of land next door to yours and builds an abattoir on it. This makes your property stink off rotten meat all the time and be constantly swarming with flies, making it pr...	[ "A development easement is a legal agreement by which a landowner surrenders the right to develop a designated parcel of property. Some local and state governments have programs to acquire development easements from private landowners to prevent conversion of farmland to other uses.\n", "Planning permission in th...
how do humans taste things like smoke and metallic flavors if there are only five tastes (salty,sweet, sour, bitter, umami)?	While the tongue only detects 5 ‘tastes’, smell is also a compnent, and it is this that creates ‘flavour’. Without any sense of smell an apple and onion would taste VERY similar. Food is ‘smelt’ through olfactory glands in the nose, via the internal nasal cavity. EDIT: Corrected location of glands per several commente...	[ "The Minbari sense of taste is not as developed as that of human beings, but they have a more acute sense of hearing. Because of this weak sense of taste, Minbari prefer hot, spicy foods. Minbari do not drink beverages containing alcohol because it affects their systems in a way that causes psychosis and homicidal ...
how do bagged cereal companies not get sued?	A patent only lasts about 20 years in most cases. So it is perfectly fine to make the exact same product. Thus, it is only the trademark laws that you have to get around. If you can argue that a person wouldn’t confuse your Big Fatty’s sugared broccoli squares with Nestle’s sugared broccoli squares, then you are all go...	[ "The cereal gained popularity for commercials often depicting squirrels stealing the cereal by outsmarting the owners. Among the most popular was Robo-Squirrel, in which a cyborg squirrel does serious damage to steal the cereal.\n", "On November 22, 1977, Jenner went to San Francisco to refute charges filed by Sa...
Why didn't Scotland rise against British reign as Ireland did in the modern history?	Because Ireland was effectively ruled as a colony, politically separate from England but completely subordinate to it. The native Irish were treated pretty horrifically - in fact, Theodore Allen in his book The Invention of the White Race makes a strong analogy between English racism towards the native Irish and the ...	[ "Scotland, meanwhile had remained an independent Kingdom. In 1603, that changed when the King of Scotland inherited the Crown of England, and consequently the Crown of Ireland also. The subsequent 17th century was one of political upheaval, religious division and war. English colonialism in Ireland of the 16th cent...
Whose portrait is depicted in this image from the USSR in 1920?	I've been wondering about this too. I think it might be [Mikhail Frunze](_URL_1_), who was a Red Army Commander during the Civil War. Edit: Yes, it is Frunze. [Here's the same photo](_URL_0_) with a biography of him on Spartacus.	[ "On the stamps of the USSR, Lenin was most frequently portrayed among the Bolsheviks. After 1923, his pictures were present on about 11% of all Soviet stamps. Lenin portrait first appeared on a stamp series that was the printed immediately after his death in 1924. Images of the first Soviet leader soon became ubiqu...
Education in ancient Egypt	The ancient Egyptians used two writing systems, hieroglyphics for religious literature and hieratic for everything else (administration, governmental edicts, mathematics, etc.). We know that schools attached to important temples and government departments definitely existed, and were presumably staffed by priests and ...	[ "In technology, medicine, and mathematics, ancient Egypt achieved a relatively high standard of productivity and sophistication. Traditional empiricism, as evidenced by the Edwin Smith and Ebers papyri (c. 1600 BC), is first credited to Egypt. The Egyptians created their own alphabet and decimal system.\n", "The ...
how do astronauts shave?	Who other than Chris Hadfield to answer the question: _URL_0_	[ "BULLET::::- Apollo 10 returned to Earth, after a successful 8-day test of all the components needed for the upcoming first manned Moon landing. The aircraft carrier \"USS Princeton\" was within three miles of the splashdown target in the South Pacific and recovered the capsule. The three astronauts— Cernan, Staffo...
why do bands keep pretending to end a rock show, but always comeback for an encore to play like 2-3 of their best songs?	it's building hype. and in many cases they: (one of this options) 1. love the crowd, so they want to give them more 2. pretend to love the crowd, so they want to make them happy.	[ "Since then, Rock@Random does not repeat songs too frequently, and does not play the same songs in the same order. It provides a great variety of rock music that is safe for public places because to the editing of profanity. The range of music is from Iron Maiden to Bob Seger, Judas Priest to Pink Floyd, Nirvana to...
to me, why can't japan just print money	Okay, so, here's what you need to understand: when the government prints money, they are tricking everyone into spending more money. People aren't truly richer, because there isn't more stuff. There's just more worthless pieces of paper. The second thing you need to understand is that when the government prints mo...	[ "The practice of \"oshigami\" arose due to differences in the sales infrastructure of newspapers between Japan and other countries with large newspaper industries. Japanese print media is primarily funded from the sales of the media itself, rather than the sale of advertisements within the media, as is common in th...
Tattoo with skin cells gene spliced to glow?	What you're describing is all technically possible. We are able to [transfect human cells to express GFP](_URL_0_), a commonly used marker that fluoresces green under UV light. We are also able to culture skin cells in vitro for the purpose of [future engraftment](_URL_1_). The biggest issues are not what you sa...	[ "Local allergic responses to many tattoo pigments have been reported, and allergic reactions to tattoo pigment after Q-switched laser treatment are also possible. Rarely, when yellow cadmium sulfide is used to \"brighten\" the red or yellow portion of a tattoo, a photoallergic reaction may occur. The reaction is al...
the limit of tornado wind speed and why tornadoes might never become ef6	Tornado and hurricane scales run from "Ehh"(EF0/Tropical storm) to "OH SHIT!"(EF5/Cat 5), in both cases we give the upper category an open upper bound. EF5 tornadoes have wind speeds > 200 MPH, even if you find a 300 MPH tornado, it would still be greater than 200 MPH and fall into the EF5 bucket An EF5 tornado wil...	[ "Tornadoes wind speeds generally average between and . They are approximately across and travel a few kilometers before dissipating. Some attain wind speeds in excess of , may stretch more than a across, and maintain contact with the ground for more than .\n", "Tornadoes' wind speeds generally average between and...
What kind of fish is this? Caught in the Gulf of Mexico off of the Florida coast.	Looks like a Frogfish/Anglerfish of the genus Antennarius.	[ "This species is distributed in the Atlantic Ocean and Gulf of Mexico along the eastern coasts of North America from Maine to Yucatán. It does not occur in the West Indies. It is well known in the Chesapeake Bay, where it is the most abundant fish.\n", "Its range is along the eastern coast of North America from s...
a small-case 4-letter password has 456,976 possible combinations. why is there a need for even stronger passwords?	While ~457,000 sounds like just an absolutely unfathomably large number to a human, that's actually child's play when it comes to computers. [Kasperky Labs](_URL_2_) estimates that an average computer that's not even particularly specialized to password cracking can attempt roughly 7100 passwords every second. That mea...	[ "The full strength associated with using the entire ASCII character set (numerals, mixed case letters and special characters) is only achieved if each possible password is equally likely. This seems to suggest that all passwords must contain characters from each of several character classes, perhaps upper and lower...
Why is it that you can cut/penetrate things so easily with pointy objects? Why is it that a greatly increased pressure from a needle or knife causes abrasion?	Think of a person laying on a bed of nails. The person's force is fixed, lets say 250lb. However, obviously laying on an entire bed of nails is safe, and laying on a single nail is not. This comes down to the strength of the molecular bonds of the persons skin. If you apply enough force between two molecules (or cell...	[ "A sharp object works by concentrating forces which creates a high pressure due to the very small area of the edge, but high pressures can nick a thin blade or even cause it to roll over into a rounded tube when it is used against hard materials. An irregular material or angled cut is also likely to apply much more...
why the hippies were so horrible to soldiers returning from vietnam	Viet Nam was the first televised war. Korea, WWII, and even some from The Great War may have had newsreels at the movies, but for the first time you could see Soldiers engaging in an unpopular war. Showing the war on the 6 o'clock news also meant that the draftees knew exactly what they were getting into. With WWII, ...	[ "Upon his return to the United States, Rambo discovered that many American civilians hated the soldiers returning from Vietnam, and he claimed that he and other returning soldiers were subject to humiliation and embarrassment by anti-war \"hippies\" who threw garbage at them, called them \"baby killers\", and exclu...
What where the major advantages/disadvantages of the Roman testudo formation?	While you're waiting, check out these threads for information on the turtle formation: [Roman testudo in medieval times](_URL_1_) by /u/novashadow1324 [Military historians, can you explain why infantry forming square (or other similar defensive formations such as the Roman "turtle") were effective at protecting infan...	[ "Phalanxes facing the legion were vulnerable to the more flexible Roman \"checkerboard\" deployment, which provided each fighting man a good chunk of personal space to engage in close order fighting. The manipular system also allowed entire Roman sub-units to maneuver more widely, freed from the need to always rema...
What weapons were used in the Franco-Prussian War?	Both French and German infantrymen were armed with a breech-loading, bolt action rifle utilizing a paper black powder cartridge. The German and French variants (Dreyse "needle gun" and Chassepot model 1866, respectively), were a marked improvement on the muzzle loading rifle-muskets they replaced, and the Franco-Prussi...	[ "The Potzdam Musket was the standard infantry weapon of the Royal Prussian Army (German: \"Königlich Preußische Armee\") from the eighteenth century until the military reforms of the 1840s. Four models were produced—in 1723, 1740, 1809 and 1831.\n", "Also in 1870, the Bavarian regiment of the Prussian army used a...
What do non-Islamic historical accounts say about Mohammed?	I quoted pretty much all the contemporary mentions of Muhammad [here](_URL_2_), let me know if you have any questions! Edit: Sounds like there are a lot of follow-up questions to this, so I might as well link my answers explaining the [success of the Arab Conquests](_URL_3_), [early Christian responses to Islam](_URL...	[ "Holland looks at the earliest evidence for Muhammad, Mecca and Islam in the first century of the Arab Empire, pointing to a lack of evidence in the historical record to support the traditional account. He points out that there is almost no contemporary historical evidence about the life of Muhammad, with no mentio...
Will a single gold atom have color? 10? At what point do we notice the color?	Color as we experience it in everyday life is mostly caused by the way many atoms are bonded together. For instance, carbon atoms bonded into a graphite pattern are gray while carbon atoms bonded into a diamond lattice are clear. Single atoms don't have color in the traditional, everyday, sense. But a single atom still...	[ "Blue gold is an alloy of gold and either gallium or indium. Gold–indium contains 46% gold (about 11 karat) and 54% indium, forming an intermetallic compound AuIn. While several sources remark this intermetallic to have \"a clear blue color\", in fact the effect is slight: AuIn has CIE LAB color coordinates of 79, ...
why my computer lags when only 50% of the cpu is being used	You've got a bottle-neck! It doesn't matter what system you run, just about every single one of them have multiple things going on all at the same time. Most of them are pretty vital, such as checking to see if you have pressed a key on the keyboard to minor ones that check to see if Adobe Acrobat is the latest version...	[ "CPU time and CPU usage have two main uses. The first use is to quantify the overall busyness of the system. When the CPU usage is high, the user may experience lag. Such high CPU usage indicates insufficient processing power. Either the CPU needs to be upgraded, or the user experience reduced, for example, by swit...
if a straight razor, single blade, is the closest shave we can get, then why do companies keep adding blades?	A multi-blade razor basically compensates for an improper or imperfect shaving technique. The cartridge attempts to force you to use the proper angle for the blades, and the multiple blades take advantage of the pulling effect of the preceding blades to cut the hair even closer to the skin. In reality, about 3 blades...	[ "Still others argue that straight razors provide a superior shave through a larger blade and greater control of the blade, including the blade angle. Straight razors cover a much greater area per shaving stroke, because their cutting edge is much longer than any of the multi-blade razors.\n", "Double-edge razors ...
If it was so easy to defend, why did the allies 'have to' attack Omaha Beach on D-Day?	All of the beaches had fairly small gaps in between them, but the Omaha landings would serve to link the American landings further north at Utah, with the Anglo-Canadian landings at Juno and Gold, and thus to the other British landing at Sword. If they had NOT landed at Omaha, the gap between Gold, Sword and Juno Beach...	[ "Merging the American beachheads at Utah and Omaha Beach was a D-Day objective of the amphibious forces but was not achieved because of heavy German resistance at Omaha. Moreover, Allied intelligence believed that three German divisions were massing to drive a wedge between them. Supreme Allied Commander General Dw...
Body Temperature and why we can stay alive 90 degrees below our body temperature but will die 90 degrees above.	It is much easier to keep heat in with insulation than it is to get rid of excess heat with sweating or other means.	[ "Heat is lost much more quickly in water than in air. Thus, water temperatures that would be quite reasonable as outdoor air temperatures can lead to hypothermia in survivors, although this is not usually the direct clinical cause of death for those who are not rescued. A water temperature of can lead to death in a...
realistically, what would have to happen before games (especially vr) can match the photo-realism of film cgi?	Think of it this way. The deadline for rendering 120 minutes of movie is around 2 years. The deadline for rendering 120 minutes of video game is 120 minutes + 33ms. Even counting the fact that movies need to be developed, then rendered, that still leaves about 1 year of rendering available for movies. No matter...	[ "Nevertheless, despite the fluidity of CGI animals and monsters, purely visual effects are often panned, or, at least, not preferred by discerning film viewers. It is extremely difficult to mimic realistic lighting, leading to most CGI creatures and characters looking obviously fake when placed alongside real envir...
In the densest parts of galaxies, how close can stars get to one another?	Although a pretty rare event, they can [collide](_URL_0_), or in other words, they can get arbitrarily close. The densest regions are the galactic nuclei as well as the cores of globular clusters, in which you can have thousands of stars per cubic parsec. The core of M 32, a satellite galaxy of the Andromeda galaxy h...	[ "Because of their high density, close encounters between stars in an open cluster are common. For a typical cluster with 1,000 stars with a 0.5 parsec half-mass radius, on average a star will have an encounter with another member every 10 million years. The rate is even higher in denser clusters. These encounters c...
What are some good books about the Ethiopian Revolution, the Ethiopian Civil War, and/or the rule of the Derg and Mengistu in general?	Robert D. Kaplan's "Surrender Or Starve" is not in-depth and the scope is wider than Ethiopia, but is a good start, and Kaplan is always engaging.	[ "The Derg overthrew the Ethiopian Empire and Emperor Haile Selassie in a coup d'état on 12 September 1974, establishing Ethiopia as a Marxist-Leninist communist state with itself as a military junta and provisional government. Various left-wing, ethnic, and anti-communist opposition groups supported by the United S...
Did segregation laws in the U.S. South "technically" apply to both blacks and whites?	Some discriminatory laws were written in a way that, at least theoretically, applied to both blacks and whites. Virginia’s anti-miscegenation law forbidding interracial marriage banned marriage between “a white person and a colored person.” Mildred and Richard Loving challenged the law, arguing that it violated the E...	[ "In 1896, the United States Supreme Court decision \"Plessy v. Ferguson\" upheld the constitutionality of racial segregation under the doctrine of \"separate but equal\". This decision led to the proliferation of Jim Crow laws throughout the United States. These laws mandated or explicitly allowed segregation in vi...
Does the deep ocean water pressure make water flow more difficult?	Short answer: no. Longer answer: currents are driven by pressure gradients, amongst other things such as gravity. On short time and space scales, water tends to flow horizontally from regions of high pressure towards regions of low pressure. In the deep ocean high pressures can be caused either by changes in the sea...	[ "The bulk modulus of water is about 2.2 GPa. The low compressibility of non-gases, and of water in particular, leads to their often being assumed as incompressible. The low compressibility of water means that even in the deep oceans at 4 km depth, where pressures are 40 MPa, there is only a 1.8% decrease in volume....
car motor oils.	If you run a finger through water and then run your finger through honey, do you feel the difference in how thick the two different liquids are? That thickness is called viscosity, and it applies to all liquids. When you're using an oil, it's important to match its viscosity (when dealing with oil, this is also refer...	[ "Motor oil, engine oil, or engine lubricant is any of various substances comprising base oils enhanced with additives, particularly antiwear additive plus detergents, dispersants and, for multi-grade oils viscosity index improvers. Motor oil is used for lubrication of internal combustion engines. The main function ...
What were the thoughts about static build up and shock to people in the past, and was it seen as a sort of witchcraft if everyone has done it at least a dozen times?	There is an excellent older answer to this question by u/hillsonghoods [here](_URL_0_). Just because people in the past didn't have our scientific understanding of the phenomenon, doesn't mean that they didn't have a secular theory of what supposedly caused it. The precursor to modern science isn't witchcraft and super...	[ "In the Netherlands in 1746 Pieter van Musschenbroek's lab assistant, Andreas Cuneus, received an extreme shock while working with a leyden jar, the first recorded injury from man-made electricity. By the mid-19th century high-voltage electrical systems came into use to power arc lighting for theatrical stage light...
how did big army get fed in the past like durring big conquest like crusade	A few ways. Requisitioning. For an army on their own territory, they will have legal authority to demand supplies, food, shelter, etc. from any nearby residents. This can be extremely difficult for the peasants and some even starve to death. If they refuse bad things can happen. Pillaging. Invading armies basic...	[ "Prior to the Thirty Years' War, the laws of the Holy Roman Empire provided for funding armies by raising special war taxes. The funds needed for the large armies raised during the war however exceeded the income of the respective warlords from those taxes, and forced them to resort to additional, unfavourable meas...
if republicans control both houses of congress, why was it so hard to get a homeland security bill passed?	The Republican Party is not united. The establishment faction and the Tea Party faction disagreed over the bill. The establishment faction wanted to pass it. The Tea Party wanted to use the bill as leverage against Obama in order to force him to take back his executive orders on immigration.	[ "The Republican House had narrowly passed a bill on December 20, 2012, which would have replaced only the defense side of the sequester with cuts to programs including food stamps, Dodd-Frank and the Patient Protection and Affordable Care Act. In February with their reduced majority, key Republicans admitted that t...

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