question stringlengths 3 301 | answer stringlengths 9 26.1k | context list |
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where did the idea that classical music makes infants smarter come from, and has it been proven? | There was a study that showed pretty well that listening to music made adults temporarily better at doing a spatial reasoning paper folding task.
This sort of melted into "classical music only specifically makes people smart" to "classical music makes babies smart". It's some pretty big leaps from the original study.... | [
"Felix Carrasco is aware of the importance of early approach of classical music to children. This is why this project was entirely thought for them. Beautiful stories such as Peter and the Wolf (Prokofiev), Carnival of the Animals (Saint-Saëns), and The Young Person's Guide to the Orchestra (Britten) are included i... |
marvel movie rights distribution | [Infographic courtesy of The Geek Twins.](_URL_0_)
I *think* the reason Marvel are OK with using Scarlet Witch and Quicksilver is that they're both X-Men characters and members of the Avengers, but I'm not sure.
The whole arrangement is because of Marvel trying to push out into TV and film from the 70's onwards and ... | [
"Meanwhile, Marvel Entertainment Group, Inc. was in such dire financial straits that they sold off their characters' film rights to several major movie studios, including Universal Pictures. MCA then eventually negotiated with Marvel for the theme park rights to their characters and both companies signed an agreeme... |
what is a "startup" company and how do they work? what is the employee/department structure like? | - A startup could have been formed last week or 4 years ago.
- They could be working in a garage out of a $1000 investment from a founder, or a 5 million venture capital they painstakingly raised over several rounds of financing after showing steady improvements and meeting the targets they promised they would.
- They... | [
"Internal startups are a form of corporate entrepreneurship. Large or well-established companies often try to promote innovation by setting up \"internal startups\", new business divisions that operate at arm's length from the rest of the company. Examples include Bell Labs, a research unit within Bell Corporation ... |
What sort of toys did Roman children play with? | Balls were very popular (usually inflated bladders). This example is Greek, but I believe the scene in the Odyssey in which Odysseus washes up on shore and Nausicaa is playing ball with her companions is the oldest mention of a ball game in western literature.
Children also commonly played with dolls and carved toys a... | [
"Roman children had different clothing from adults until they came of age or were married. Children’s education was normally practiced at home. When children were not being educated their play time consisted of a variety of toys such as rattles, dolls made of cloth, clay, or wax, toy weapons, letter blocks, tops, b... |
I heard that jupiter is a failed star due to not being massive enough to start a fusion reaction. If this is true, can we detonate a fusion bomb on the planet to start a chain reaction? | Nope, because Jupiter is far from being a failed star. For an object to be a star, it has to have at least 75 jupiter masses, because only then it could have a permanent hydrogen fusion. Objects with lower mass may have deuterium/lithium fusion and are called brown dwarfs. They are in the range of about 13 - 75 jupiter... | [
"In massive stars, fusion continues until the iron core has grown so large (more than 1.4 ) that it can no longer support its own mass. This core will suddenly collapse as its electrons are driven into its protons, forming neutrons, neutrinos, and gamma rays in a burst of electron capture and inverse beta decay. Th... |
What pre-modern examples are there of movements for racial equality? (more generally, political/legal economy of ethnic groups) | During the era of the Roman Republic, citizen rights were only granted to people of Roman birth and heritage. Even Rome's closest allies - the other Italian cities - were not granted citizenship.
There was a lot of discontent people as those cities had been allied with Rome for hundreds of years, and were instrumenta... | [
"Over time, it has changed in fundamental ways the manner in which blacks and whites interact with and relate to one another. The movement resulted in the removal of codified, \"de jure\" racial segregation and discrimination from American life and law, and heavily influenced other groups and movements in struggles... |
When you connect a voltage to a wire, how long will it take for it to be observable on the other end of the wire? Does the voltage propgate via electrons at the speed of light? Or is it slower? | Practically, it is slower than the speed of light, because of the capacitance of the wire (which is very roughly about 10pF a foot, depending on the wire). With long, fine/high resistance wires, this can make for a significant filter. But in a theoretical, frictionless, vacuum world, one often says it happens at the sp... | [
"The interesting consequence of this behavior is that, while a single 2 mm length of wire has a delay of 4 µs, two separate 1 mm wires only have a delay of 1 µs each. The two separate wires cover the same distance in half the time! By cutting the wire in half, we can double its speed.\n",
"The time it takes for a... |
how come even though imgur's servers are over capicated quite a few times a day, we are still able to view them on reddit? | Rendering the PHP code and performing the SQL queries to dynamically render the Imgur site takes a lot of processing power. Their service provider will redirect to the Over Capacity page automatically if they are exceeding their allocated processor utilization. With a direct image URL, none of that needs to happen, it'... | [
"Imgur used to have a policy to keep images unless they went three months without receiving any views, at which point (unless they were Pro account images) they might be removed in response to space needs. In early 2015 it was announced all images will be kept forever (even if not added from a Pro account) and only... |
why hasn't the catholic church reported all of the priests with alleged child abuse charges to their local authorities? | So hopefully mine or someone else's level headed comment will get through the typical reddit bullshit.
So forget about the bad press. The bad press has already happened. They aren't saving an image as much as they straight up don't know what to do.
What would you do? A massive chunk of your organization starts doing ... | [
"Several priests who abused children in the United States were Irish National, notably Patrick Colleary, Anthony O'Connell and Oliver O'Grady. In August 2018, a list was published which revealed that over 1,300 Catholic clergy in Ireland had been accused of sexual abuse, with 82 of them getting convicted.\n",
"On... |
At what stage do people typically "feel" cancer? How is it possible for someone to just get diagnosed at stage 4, at that point of metastasization shouldn't the person be in massive pain at stage 3 already? | There's no answer to this as it is vastly vastly different between any of the 200+ types of cancer, and even within a type it can depend on where exactly the tumor is.
For example, the most common subtype of Non-Hodgkin Lymphoma shows up as a very rapidly growing lymph node in the neck or chest (over a few weeks). It ... | [
"People who have finished cancer treatment often have psychological and physical medical challenges. These effects can vary from person to person, change over time, and range in intensity from mild and intermittent to fully disabling. They commonly include fatigue, pain, sleep problems, physical side effects like l... |
What was it like to run a family restaurant in south in 1960 if you were not a racist and wanted to serve everyone who walks in through the door as best you can? | Don't forget that before the Civil Rights Act of 1964, Southern cities such as Atlanta and New Orleans segregated their restaurants by law. For example, Section 369 of the Birmingham, Alabama Racial Segregation Ordinances contained the following clause:
> It shall be unlawful to conduct a restaurant or other place fo... | [
"Integrating lunch counters in the Southern United States through the use of sit-in political protests in the 1960s was a major accomplishment of the Civil Rights Movement. These involved African Americans and their supporters sitting at the lunch counter in areas designated for \"whites only\", insisting that they... |
why is there a certain smell to really cold freezers? | The refrigerant is odorless ( _URL_0_ ). You're most likely smelling something resulting from the accumulation of moisture, the food, packaging, etc. | [
"The experience of eating favored foods with a cold often disappoints. This is because congestion blocks nasal passageways through which air and flavor molecules enter and exit, thus temporarily reducing retronasal smell capacity.\n",
"A cold chill (also known as chills, the chills or simply thrills) is described... |
Would a pool of water protect you from the pressure wave and fiery heat of a bomb's explosion? | The water may offer some protection from an explosion occurring above it since part of the pressure wave is reflected as it hits the surface. It would also quench fires and keep you cool, preventing fatal burns.
In addition, most of the fatalities from explosions tend to be due to shrapnel flying away from it and tea... | [
"BULLET::::- Mass and incompressibility (all explosions) – water has a much higher density than air, which makes water harder to move (higher inertia). It is also relatively hard to compress (increase density) when under pressure in a low range, say up to 100 atmospheres. These two together make water an excellent ... |
what determines the cc of an engine? what makes a bike 250cc vs. 500cc also why is a higher cc faster(typically)? | It's a measure of volume in **c**ubic **c**entimeters that the pistons in the engine can displace. Very simply put, bigger engines are more powerful. | [
"The categories based on engine size frequently use the following thresholds of engine capacity: 0-50cc, 66-85cc, 85-100cc, 124cc-200cc, 201-250cc, and larger than 250cc. Accordingly, a beginning rider on a 200cc motorcycle would likely compete in the 200C class, which denotes both the capacity of his or her motorc... |
why is it that the nations of the commonwealth (canada, uk, australia, etc.) do not have the same traveling protocol as, say, the eu? why can't citizens of commonwealth nations travel into other commonwealth nations without showing passports, etc? | Simply because there is no agreement between the commonwealth countries that would allow that. Despite being linked by history and a queen, they are still different countries and a travel agreement would require lots of negotiating and back and forth and so on. | [
"Like the TWOV rules of other countries, travelers must be in transit to a different country other than the country of departure, hence passengers who travel between the U.S. territories and contiguous United States, Alaska or Hawaii are ineligible for TWOV, unless one of their flights has a stop in another country... |
why are 'geniuses' always good at math? | It honestly depends how you view geniuses.
If like a lot of people you think geniuses dont simply have to be very smart and have a high IQ. For example if you think people can be lyrical geniuses or comedic geniuses etc. Than they likely wont be good at math.
If you are only talking about smart people they are likely... | [
"A view associated with Francis Galton author of \"Hereditary Genius\" (1869). suggests that \"when asked to explain why some children do better in math than others, Asian children, their teachers, and their parents point to hard work, their American counterparts to ability.\"\n",
"Genius (also known as the Geniu... |
Is the gravitational pull of an object the same as the sum of the gravitational pull of the atoms that make up that object? | Practically speaking, yes. If you look at the Newtonian theory of gravity, that is exactly what happens, and the Newtonian theory is close enough to the truth on the level you are describing. If you look at really massive objects (like neutron stars) then the Newtonian theory is no longer accurate and you need General ... | [
"In this way, it can be shown that an object with a spherically-symmetric distribution of mass exerts the same gravitational attraction on external bodies as if all the object's mass were concentrated at a point at its center. (This is not generally true for non-spherically-symmetrical bodies.)\n",
"The strength ... |
At the end of WWII in Europe, when Germany was being defeated in April, 1945, and the Allied forces were closing in from the east and the west, were there any incidents where the Russians and Americans/British accidentally fired on each other not realizing that they were fighting their ally? | Well, searching through the LINKS provided, this seems to be the best example provided so far:
> It was Nov. 7, 1944 when a flight of American P-38s on a routine mission over Kosovo noticed an inviting ground target: a column of enemy infantry and armour out in the open and rolling towards a nearby town. Within mome... | [
"Following the lull in fighting, known as the \"Phoney War\", Germany invaded western Europe in May 1940. Six weeks later, France, in the mean time attacked by Italy as well, surrendered to Germany, which then tried unsuccessfully to conquer Britain. On September 27, Germany, Italy, and Japan signed a mutual defens... |
How can I estimate the size of clouds I see in the sky? | I am not a meteorologist, but can offer some geometrical perspective.
If you know the altitude, you can get the rest. From the angular position above the horizon and the altitude, you can get the distance by right triangle trigonometry. Alternatively, from the distance and the angle above the horizon, you can get the... | [
"Cloud top height can be estimated from the ground by triangulation. However, this is often inconvenient as this is practically feasible only for isolated clouds in full view of (and some horizontal distance away from) the observers. Ground-based radars can be used to derive this cloud property (see this paper for ... |
how do audio wires work? how does a unit send something through metal wires that comes out of a speaker as a song/voice/etc? | Ever shaken a large sheet of paper back and forth and listened to the wobbling sound it makes? It's from the air being pushed back and forth. In other words a very primitive speaker.
Next, take 2 magnets, in one position, the attract each other, in a different position they repel each other. Now what if we can turn on... | [
"Speaker wire is used to make the electrical connection between loudspeakers and audio amplifiers. Modern speaker wire consists of two or more electrical conductors individually insulated by plastic (such as PVC, PE or Teflon) or, less commonly, rubber. The two wires are electrically identical, but are marked to id... |
What's the smallest object that can become a black hole(due to plank length)? | The limit is around the Planck mass. When approaching this limit from above quantum gravity effects become important. | [
"A small mass has an extremely small Schwarzschild radius. A mass similar to Mount Everest has a Schwarzschild radius much smaller than a nanometre. Its average density at that size would be so high that no known mechanism could form such extremely compact objects. Such black holes might possibly be formed in an ea... |
i really don't want to sound racist, but why do so many indian people smell? | If you cook a lot with spices (rather than store bought jars) then it tends to get in your clothes and hair. Also I find I tend to sweat a curry smell when I've been eating a lot. | [
"BULLET::::- gālí rén (咖喱人) - A much more common contemporary term used to refer to Indians, derived from the use of curry in Indian cuisine and the perception that Indians eat food to some Chinese find to have a strong smell, and which Indians eat with their hands, a practice that many Chinese find to be dirty and... |
How is an ICBM, used to carry warheads thousands of miles over a presumably high altitude, different than a rocket used to deliver objects into space? Specifically, why does weather affect a space launch window and not affect a potential ICBM launch? | Many ICBMs have been repurposed to launch payloads to space and many rocket designs are based on ICBMs.
The difference is simply the expected reliability. If you lose a satellite worth $1B that is bad, better wait a day with the launch. If you lose a few nuclear weapons when both countries launch hundreds against each... | [
"To counter air defenses en route to the target, remaining at a low altitude for as long as possible allows the bomber to avoid radar and visual tracking and the launch envelope of older missile systems designed to be fired at targets overflying the missile site. However, a level pass at the target at low altitude ... |
As one of the effects of MDMA on the human brain, what is the exact mechanism by which MDMA affects the (left) amygdala? | MDMA causes release of massive amounts (well, "massive" in a relative sense) of serotonin and dopamine. Activation of seritonergic neurons in the amygdala is linked to a decrease in anxiety...thus, this is suggested to be part of the mechanism by which MDMA could be useful for PTSD and severe anxiety disorders. MDMA al... | [
"At high doses, MDMA induces a neuroimmune response which, through several mechanisms, increases the permeability of the blood-brain barrier, thereby making the brain more susceptible to environmental toxins and pathogens. In addition, MDMA has immunosuppressive effects in the peripheral nervous system and pro-infl... |
How is it that (kinetic) energy appears or disappears based on your frame of reference? | Kinetic energy is only conserved within one particular reference frame. | [
"This equation states that the kinetic energy (\"E\") is equal to the integral of the dot product of the velocity (v) of a body and the infinitesimal change of the body's momentum (p). It is assumed that the body starts with no kinetic energy when it is at rest (motionless).\n",
"Correspondingly the kinetic energ... |
Is there such a thing as a non-reflective liquid? | There are actually metamaterials that have [Negative Indices of Refraction](_URL_0_). They were only discovered recently, but are interesting nonetheless. These substances will not reflect any light, no matter what angle you look through them at. | [
"BULLET::::- Reflected Color - Uncoated glass reflects light uniformly and does not cause reflected light to be distorted (a white light source reflected in a non-coated glass pane will still appear white). However, anti-reflective coatings typically cause some wavelengths of light to be reflected more than others,... |
if grapes become raisins when dried, why does mango when dried, remain as dried mango. | Well with plums to prunes it’s even weirder!!
Grapes dry into raisins. When juiced we say grape juice! No such thing as raisin juice!
Plums dry into prunes. However, there is such a thing a prune juice! How does prune JUICE exist if it’s dry plums? How can you juice something that’s been dried?? | [
"Raisins are produced commercially by drying harvested grape berries. For a grape berry to dry, water inside the grape must be removed completely from the interior of the cells onto the surface of the grape where the water droplets can evaporate. However, this diffusion process is very difficult because the grape s... |
why do animals shed fur all their lives, but when you make a fur coat, it doesn't shed? | Because fur on an animal works like hair on a person - it grows and sheadding is a built in way to keep it clean and maintained. Along with grooming habits like licking.
A fur coats fur does not grow, as a fur coat is not alive. And the skin has been treated to retain the fur as much as possible. | [
"Their long, coarse fur also protects them from sun and rain. Their fur, unlike other mammals, flows from belly to top, not top to belly, allowing rainwater to slide off the fur while the animal is hanging upside down.\n",
"Conservation efforts must take into account the properties of both the fur and skin. The o... |
how do car doors freeze shut? | There's one main thing that causes this and it is the rubber gasket that lines your entire door.
Over time, that gasket gets moisture in it. Since it's a rubbery porous material, it holds onto it. When it starts to get cold, that moisture freezes and sticks to the door frame. The only reason it does this when you leav... | [
"A lockout system is armed when the driver turns the ignition key to the \"on\" position and carries out a specified action, usually flicking a hidden switch or depressing the brake pedal twice. It is activated when the vehicle drops below a certain speed or becomes stationary, and will cause all of the vehicles do... |
Why is the moon's density lower than Earth's density? | You're correct about the formation theory. By that time, many of the heavier elements had already settled to Earth's core, and the Moon was formed from outer layers of Earth and possibly the impacting body which were thrown into orbit by the impact. So the Moon's formational material was a less-dense sample of the Eart... | [
"The fact that the Moon is less dense than the Earth is advanced as support for it to be hollow. The moon's mean density is 3.3 g/cm whereas the Earth's is 5.5 g/cm. One explanation of this discrepancy is that the moon may have been formed by a giant impact which ejected some of the early Earth's upper crust into i... |
why are so many resolutions considered 2k? | Because '2K' is a marketing term with no formal definition. Basically what the people selling the screens are trying to say is that the resolution is better than 1080p. | [
"5K resolution refers to display formats with a horizontal resolution of around 5,000 pixels. The most common 5K resolution is 51202880, which has an aspect ratio of 16:9 with around 14.7 million pixels (just over seven times as many pixels as 1080p Full HD), with four times the linear resolution of 720p. This reso... |
why is it that the word allegedly is used even though there is video evidence that the act was in fact committed? | If there's a video of a person who looks almost exactly like, say, "Mike Jones" robbing a bank and then smashing a kitten, say, with a brick or something, and the news says, "Mike Jones smashed a kitten with a brick after robbing a bank," and it turns out to be that one person in a million who looks like Mike Jones, th... | [
"Suppression of evidence is a term used in the United States legal system to describe the lawful or unlawful act of preventing evidence from being shown in a trial. This could happen for several reasons. For example, if a judge believes that the evidence in question was obtained illegally, the judge can rule that i... |
why remove the downvote/upvote counter? | > Why remove the downvote/upvote counter?
Because it's never been accurate in the first place. Their "fuzzing" algorithm adds fake votes to comments and submissions to prevent bot networks from being able to know if they're accurately able to game the voting system. | [
"An option of casting a downvote is another feature of the proposed method, which allows voters an even wider scope to express their preferences by letting them designate a candidate they do not want to see elected. It is important to note that the idea of a downvote is not a novel concept. It is important to note ... |
breast implants | Silicone is placed in the required area. Procedure is similiar to plastic surgery. It feels good when you touch it. | [
"A breast implant is a prosthesis used to change the size, shape, and contour of a person's breast. In reconstructive plastic surgery, breast implants can be placed to restore a natural looking breast mound for post–mastectomy breast reconstruction patients or to correct congenital defects and deformities of the ch... |
Is there a limit to how many times you can gravity assist a space craft with one planet before it stops increasing its velocity? | There's an upper limit to the amount of times you can use gravity assists to accelerate without having to burn a lot of fuel to get another one. If you hit the escape velocity out of the solar system, you'd have to slow down at some point to loop back and get another encounter with anything in that solar system. The am... | [
"Similarly, while the orbital speed of an outer planet is less than that of the Earth, a spacecraft leaving the Earth at the minimum speed needed to travel to some outer planet is slowed by the Sun's gravity to a speed far less than the orbital speed of that outer planet. Thus, there must be some way to accelerate ... |
Could a musket actually be tap-loaded effectively and regularly, or is that just a myth? | Yes, you can tap-load a musket for a couple of shots, IF, as was typical, the ball is a loose fit in the bore. The tricky thing is that as the bore fouls ( and black powder creates a good bit of fouling) the ball will be tighter and tighter, and the fouling could also accumulate a little heavier at the breech end- mean... | [
"Musketoons had a brass or iron barrel, and used a wheellock, flintlock or caplock mechanism firing mechanism, like the typical musket of the period. They were fired from the shoulder like the musket, but the shorter length (barrels were as short as a foot (30 cm) long) made them easier to handle for those in restr... |
broadband pricing tiers — business vs. home | One reason that business is more than home is because it usually comes with higher uptime guarantees, different (better) technical support and issue response times, and less restrictions (generally you're not supposed run a webserver on a home connection, although you can certainly do it from a technical standpoint)
I... | [
"Middle-mile provision is a major issue in reducing the price of broadband Internet provision by non-incumbent operators. Internet bandwidth is relatively inexpensive to purchase in bulk at the major Internet peering points, and access to end-customer ports in the incumbent operator's local distribution plant (typi... |
Were there differences in the quality of metalworking between the Roman Empire and medieval Europe? | The quality of iron objects improved immensely after the collapse of the Roman iron industry.
Archaeometallurgists (people who study the metallurgy of archaeological artifacts) use a method called metallography to evaluate the quality and composition of metal artifacts. You cut a cross-section from an artifact, polish... | [
"By the height of the Roman Empire, metals in use included: Gold, Silver, Copper, Tin, Lead, Zinc, Iron, Mercury, Arsenic, Antimony (Healy 1978). As in the Bronze Age, metals were used based on many physical properties: aesthetics, hardness, colour, taste/smell (for cooking wares), timbre (instruments), aversion to... |
To what extent is Ibn Rush (AKA Averroes) regarded as the "founding father of secular thought in Western Europe"? | "Secular thought" is a tough thing to quantify here. Lots of people tend to look at him as secular simply because he opposed the orthodox Ash'ari ideas of Imam al-Ghazali, but he was by no means secular in the modern European sense. His greatest work was "The Distinguished Jurists Primer" a comparison study of the four... | [
"Ibn Rushd, often Latinized as Averroes, was a medieval Andalusian polymath. Being described as \"founding father of secular thought in Western Europe\", he was known by the nickname \"the Commentator\" for his precious commentaries on Aristotle's works. His main work was \"The Incoherence of the Incoherence\" in w... |
Why are we so dependent on bees to pollinate our crops? | Bees don't eat the pollen, they just spread it. That being said, bees are primary pollinators for a great many plants, and in some cases the exclusive pollinator. Some plants just plain aren't attractive to anything *but* a specific species, such as a certain bee. In cases of these exlusive pollinators, they is simply ... | [
"Some crops, especially when planted in a monoculture situation, require a very high level of pollinators to produce economically viable crops, especially if depending on the more generalized honeybee. This may be because of lack of attractiveness of the blossoms, or from trying to pollinate with an alternative whe... |
Why do Russian military aircraft have a teal interior paint scheme? | > easy on the eyes
That's part of the reason. It's meant to keep pilots calm in combat and allow for easier transitions when looking inside and outside. The VVS started using it in WW2 but it's been kept around with some interesting innovations; for example, Fulcrums and Flankers have instruments that glow under UV... | [
"Tasma – in Russian Cyrillic characters is a Russian GOST and ISO certified manufacturer of black and white photographic, x-ray, aerial, holographic, industrial radiographic testing, anti-fog, thermal, micrographic, and graphic arts films. It also manufactures adhesive tape, and demineralized water. Located in Kaza... |
cardinality, what is it, and how does it work? | "Cardinality" pretty much just means size. The cardinality of a set is its size.
Commonly, instead of formalizing the cardinality of a set as a particular thing, we formalize the idea of one set being bigger than another, or two sets being the same size. So if A and B are sets and |A| and |B| are their cardinalities, ... | [
"Cardinality is studied for its own sake as part of set theory. It is also a tool used in branches of mathematics including model theory, combinatorics, abstract algebra, and mathematical analysis. In category theory, the cardinal numbers form a skeleton of the category of sets.\n",
"In mathematics, the cardinali... |
How are Particle collisions imaged? | > do the detectors use Xrays?
No, all our particle detectors for particle physics are actually passive devices. They often get described in public lectures as being large digital cameras...and I think that is a reasonable (albeit simplified) way of looking at things.
So what a lot of these particle collisions you a... | [
"Each particle-target collision is called an \"event\". An elaborate data acquisition system records each event measured by the particle detectors, up to several thousand events per second on average. This data is then transferred to a \"farm\" of computing processors. Teams of physicists analyze the events, lookin... |
Help in understanding the geography of Greece at the time of the Peloponnesian war. | > Is Attica the name of the main body of land in southern Greece?
[Attica](_URL_3_) is the general area around Athens.
> Was the main body of the Pelopennes the northern landmass of Greece?
The [Peloponnesus](_URL_0_) is the big southern peninsula (Though it looks almost like an island on maps) where Sparta was.
... | [
"The Peloponnesian War was a radical turning point for the Greek world. Before 403 BC, the situation was more defined, with Athens and its allies (a zone of domination and stability, with a number of island cities benefiting from Athens' maritime protection), and other states outside this Athenian Empire. The sourc... |
how can stores sell things on sale while still making a profit? | There are two things to consider:
1. Stores have a larger markup on items than you might imagine. But they're not "ripping you off". They have to sell things at a high markup to be able to pay for the building, and pay their employees.
2. Many sale items are called "loss leaders". They sell these items to you at a... | [
"In reality, Pottery Barn—a chain of upscale home furnishing stores in the United States—does not have a \"you break it, you bought it\" policy, but instead writes off broken merchandise as a loss, as do most large American retailers. Legal doctrine also holds that a retailer incurs the risk that merchandise will b... |
Where does the energy to keep Europa's ocean liquid come from? Conservation of energy question. | [I would explain it, but wikipedia does a good enough job](_URL_0_) | [
"The energy provided by tidal forces drives active geological processes within Europa's interior, just as they do to a far more obvious degree on its sister moon Io. Although Europa, like the Earth, may possess an internal energy source from radioactive decay, the energy generated by tidal flexing would be several ... |
I found this painting cleaning out my grandfather's house- anyone know who it is (probably German)? (X post from /r/AskHistory) _URL_0_ | It is [Józef Piłsudski](_URL_0_). | [
"The house was opened to the public as a museum in 1948. A major attraction of the museum is the portrait that the artist Elizabeth Shoumatoff was painting of him when he died, now known as the \"Unfinished Portrait\". It hangs near a finished portrait that Shoumatoff completed later from sketches and memory.\n",
... |
I recently found a knife handle from a US Army mess kit and I want to know a bit more about it. | A Model 1917. Most military surplus stores have them in bins for small change. Staple of campers and Boy Scouts everywhere. | [
"Ontario Knife Company is most well known as a supplier of military knives. Throughout the years they have supplied the U.S. military with products such as the M7 bayonet, the USAF Survival Knife, the M1942 Machete, the Navy MK3 MOD 0 diving/survival knife, the M9 bayonet, and most recently, the USMC OKC-3S Bayonet... |
Until Clinton's presidency in the 90s, California voted mainly Republican senators and governors and Texas voted mainly Democrat ones. During and since Clinton, California has voted mainly Democrat and Texas has voted Republican. What caused this drastic switch? | Concerning Texas and the South (can't speak for California). I'll attempt a brief summary of many events, some of them bloody. It was a drastic switch and a drastic time.
The Democratic party began to lose the south with the passage of the Civil Rights Act of 1964 and the Voting Rights Act of 1965. (50+ years ago) T... | [
"California was a Republican stronghold in presidential elections from 1952 until 1992. During this period, the Republicans won California in every election except the election of 1964. In these years, the GOP regularly nominated Californians as presidential candidates: Richard Nixon in 1960 and 1972, and Ronald Re... |
how can cats cover themselves in saliva daily and not stink? | Cat saliva contains a natural antiseptic which keeps their fur clean.
According to wiki "Nitrates that are naturally found in saliva break down into nitric oxide on contact with skin, which inhibit bacterial growth". | [
"Regularly bathing the cat may remove significant amounts of allergens from the fur. Furthermore, regularly brushing the cat will reduce the amount of loose fur (and its attached saliva) in the air. Feeding the cat a high quality diet with plenty of omega-3 fatty acids will help keep the coat healthy and minimize d... |
how culturally and technologically advanced were natives of australia compared to native american civilizations? | Well, that rather depends how you define "culturally advanced", doesn't it?
But by the usual metrics of technological advancement, mesolithic. | [
"The indigenous Australians, far from being a primitive people, have a highly sophisticated society and worldview which, in Turner's view, is in many ways more advanced than those of modern Western civilization. According to Turner, the Aborigines have developed several social mechanisms for ensuring social and env... |
why aren't you supposed to pour boiling water on honey? | If you believe that honey has healing properties, boiling water supposedly breaks down the enzymes or whatever responsible for those attributes. Like a lot of "natural medicine", it's not really based on any science.
If you just like something sweet in your tea, it doesn't make a lick of difference. | [
"The reason for making syrup with the honey is that otherwise it might be too thick to mix well with other ingredients, especially in an ice-filled cocktail shaker (as opposed to, say, a hot tea). An advantage of honey over sugar, for making cocktails, is that it can impart floral notes and also pair well with spir... |
How reliable was pilot kill counts during WW2? What kept pilots from inflating their scores for personal gain, or countries from doing the same for propaganda purposes? | In WWII, fighter pilot kill claims were generally exaggerated ~~by about a factor or 5 to 10~~(Edit: to a degree ranging from very substantial to very extreme), when compared against enemy loss numbers in records available after the war. This is true for all countries participating in the war. Even with gun camera fo... | [
"The \"Regia Aeronautica\" tended not to keep statistics on the individual level, instead reporting kills for a certain unit, attributed to their unit commander. However, pilots were able to keep personal log books, so the few that survived through World War II give individual statistics. Here is a list of the aces... |
why do cats sometimes kill smaller animals for no reason? | Think of the cat as a wild hunting machine that just so happens has been domesticated over hundreds, thousands of years, by man to be very good at doing one thing (that humans expected of it): kill things that eat our grain. If it is a small rodent, cat's got it. Bird? cat's got it. This behaviour is taught to kittens... | [
"Cats hunt small prey, primarily birds and rodents, and are often used as a form of pest control. Domestic cats are a major predator of wildlife in the United States, killing an estimated 1.4 to 3.7 billion birds and 6.9 to 20.7 billion mammals annually. The bulk of predation in the United States is done by 80 mill... |
What kind of advancements are being made in weather forecasting? | It's probably more of the opposite, NOAA funding cuts means they won't be able to replace satellites and can barely maintain current ones. | [
"The Travelers Weather Research Center (1954-1961) was the world's first privately-owned research institute for the scientific study of weather. It pioneered the use of statistical methods, mathematical models, and computers to improve weather forecasting techniques, and was the first to state weather predictions i... |
Camel cataphracts and similar cavalry units-- the real deal or a cute little anachronism? | To make a long story short-
Armored cavalry with armored horses are a VERY old concept, and were incredibly effective.
The byzantines, at various times in their history, were infamous for deploying (comparatively) large groups of them, and using them rather skillfully in concert with pike and shot+lighter cavalry+ armo... | [
"Camel cavalry, or camelry (, ), is a generic designation for armed forces using camels as a means of transportation. Sometimes warriors or soldiers of this type also fought from camel-back with spears, bows or rifles.\n",
"Camel cavalry were a common element in desert warfare throughout history in the Middle Eas... |
cancer. | Cancer is essentially rampant cell growth. The cells in your body are constantly replicating in order to keep you alive and kicking.
How do they know when to start and stop this replication, though? There are a few genes (proto-oncogenes and tumor suppressor genes) that pretty much function as a traffic light for cell... | [
"Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. These contrast with benign tumors, which do not spread. Possible signs and symptoms include a lump, abnormal bleeding, prolonged cough, unexplained weight loss, and a change in bowel move... |
What would the effects on the human body be from going from -70F to 110F weather very quickly, as it is a difference in 140F? | Well, I happen to know some people who've gone from +200F to -100F ass naked, and they survived to tell the [awesome] story. It's called joining the "300 club", and is a common ritual for winterovers at the Amunsen-Scott South Pole station (and maybe other places, I don't know).
When the temp outside gets to -100F ... | [
"BULLET::::- The wind chill factor measures the effect of wind speed on cooling of the human body below 10 °C (50 °F). As airflow increases over the skin, more heat will be removed. Standard models and conditions are used.\n",
"The U.S. National Weather Service defines \"extreme cold\" as with winds less than . I... |
how does "making yourself heavy" make you heavier to carry? | When you "make yourself heavy", you go limp, meaning that whoever wants to carry you must support and maneuver your entire body weight. This makes you feel a lot heavier than if you were supporting yourself in small part using your legs or arms. Your instinct is to support your weight with your legs a bit where possi... | [
"Weight lifting can effectively demonstrate the effects of post-activation potentiation. For example, if a person lifts a light weight, and then lifts a heavy weight, before lifting the light weight again, the light weight will be relatively easier to lift and feel lighter the second time it has been lifted. Becaus... |
why do countrys seprate into states? | The US didn't separate into states. The states chose to unite (but still retain their existence as states). | [
"If the states do not unify into a single nation there will be a perpetual cycle of conflict between neighboring states. Their alliances or dis-unions create circumstances similar to European nations, where the cycle of aggression between neighboring nations creates the need for domestic armies and fortifications. ... |
During the French Revolution, many French officers had fled abroad, and the ones who stayed feared their own troops. The new Revolutionary Army was comprised of poorly trained conscripts against multiple, better trained armeis. So how did France mange to win the War of the First Coalition? | I want to concentrate on the period 1792-1794, which is the initial post-revolutionary period, with context surrounding these years.
After the War of the Austrian Succession in 1750 France founded the Ecole Millitare, which in 1777 became the École des Cadets-gentilshommes. Its intention was to train not just high nob... | [
"From 1793 to 1795, French successes varied. By 1794, the armies of the French Republic were in a state of disruption. The most radical of the revolutionaries purged the military of all men conceivably loyal to the \"Ancien Régime\". The \"levée en masse\" created a new army with thousands of illiterate, untrained ... |
British officers in WW1 | > the officers and higher ranks were all taken from public schools rather than due to experience
This is only partially true; yes, a great majority would have attended public school, considering that it took money and education to be an officer. As a result, most would have been upper and middle class, but this was... | [
"Field Marshal Sir William Robert Robertson, 1st Baronet, (29 January 1860 – 12 February 1933) was a British Army officer who served as Chief of the Imperial General Staff (CIGS) – the professional head of the British Army – from 1916 to 1918 during the First World War. As CIGS he was committed to a Western Front s... |
Can someone briefly explain the Lorenz Attractor? | The Lorenz Attractor is a set of differential equations which was originally formulated to describe a certain physical situation in phase space. That is, the coordinates of each point of the "line" describe the state of the system, and the line its evolution over time.
It's an attractor because with those equations a... | [
"The Lorenz system is a system of ordinary differential equations first studied by Edward Lorenz. It is notable for having chaotic solutions for certain parameter values and initial conditions. In particular, the Lorenz attractor is a set of chaotic solutions of the Lorenz system. In popular media the 'butterfly ef... |
why do the facebook app and mobile site require you to download the messenger app, when opening a desktop version on my phone lets me use the messaging system just fine? | I don't know but I refused to download FB messanger because I didn't like all the access it was requesting. If you use Chrome - just check "Request desktop site" in the settings and you can access your messages through FB in the browser. | [
"Complementing regular conversations, Messenger lets users make one-to-one and group voice and video calls. Its Android app has integrated support for SMS and \"Chat Heads\", which are round profile photo icons appearing on-screen regardless of what app is open, while both apps support multiple accounts, conversati... |
In WW2, why were troops allowed to paint on their planes etc? It seems like they would give away their position rather than modern camouflage patterns. | Painting of aircraft and the levity allowed for individual markings depended on the time, place, air service doctrine and conditions.
For example Royal Air Force and Germany-based Luftwaffe aircraft tended to be painted in the standard schemes proscribed by the high command. Individual markings such as crests, cartoon... | [
"While camouflage tricks are in principle limitless, both cost and practical considerations limit the choice of methods and the time and effort devoted to camouflage. Paint and uniforms must also protect vehicles and soldiers from the elements. Units need to move, fire their weapons and perform other tasks to keep ... |
What is the difference between vapor and gas? | All condensed phases of matter have finite "vapour pressures" meaning that they lose mass by evaporation unless/until a dynamic equilibrium with the gas phase is reached. The vapour, then, is the gaseous form of the material (from evaporation) at a temperature below its boiling point. | [
"\"Vapor\" refers to a gas phase at a temperature where the same substance can also exist in the liquid or solid state, below the critical temperature of the substance. (For example, water has a critical temperature of 374 °C (647 K), which is the highest temperature at which liquid water can exist.) If the vapor i... |
What qualifies a certain aquatic species to be called a shark? | [Six reasons.](_URL_0_) Second Google search result. Very clearly-written explanation, I like this site. | [
"The bramble shark (\"Echinorhinus brucus\") is one of the two species of sharks in the family Echinorhinidae. Aside from the eastern Pacific Ocean, it is found in tropical and temperate waters worldwide. This rarely encountered shark swims close to the bottom of the seafloor, typically at depths of , though it may... |
Could someone recommend me articles/books on the subject of the development of hereditary feudal system? | You'd probably do well to check out [*Fiefs and Vassals* by Susan Reynolds](_URL_1_). It's pretty much essential reading if you want to know the other side of the debate with Bloch's view that's been rumbling on since [Elizabeth Brown's article *The Tyranny of a Construct*](_URL_0_). | [
"With feudal barons and feudal counts one saw the introduction of a neo-feudal structure in Norway. These modern fiefs were ruled with conditioned independence by noble families, and they were hereditable. Feudal lords were equipped with extensive rights and duties. On the other hand, a fief was formally a \"domini... |
how did worms get inside a mango seed if it didn't make any holes on the outside. | They burrow inside before the seed is fully matured.
> The newly hatched larva is about 1 mm long and burrows through the pulp and into the seed where it will remain until it becomes an adult. Minimum time from hatching to seed penetration is one day. There are at least five larval instars in Hawaii. Larvae can pene... | [
"The caterpillar larvae eat all sorts of dry leaves, in which they build silken tunnels. They have also been recorded on living plants of the looking-glass mangrove (\"Heritiera littoralis\"), though the significance of this is unknown.\n",
"Once the virus reaches the seed, it is believed that it is harbored in t... |
Why was George Washington elected as "President" and not, for example, as "Chancellor", "Leader", or "Director"? Why was "President" specifically used? | [This answer](_URL_0_) by /u/bigslothonmyface explains why "President" was chosen over a more elevated title. They don't give a reason why "President" specifically was chosen though. | [
"George Washington impacted the role of the presidency from his inauguration to his retirement. From the beginning, Washington did not want to resemble a king or be referred to as one. He preferred the title \"Mr. President,\" which is how presidents are still addressed to this day. Washington also shaped the inaug... |
why do employers give new employees higher salaries, rather than rewarding loyalty and giving the better salary to employees already there? | The question you have to ask yourself is why would they.
Your coworker still works there. There is no incentive for your bosses to pay them any better than they currently do. Sure loyalty is virtuous and should be rewarded, but companies dont care about virtue. They care about making money, and every dollar that is gi... | [
"Some employees are paid more for they are presenting that they are worth a greater amount since they can perform more than one job function and thus makes a higher incentive for more employees to be able to perform better in the workplace. \n",
"The reason that employees are often paid according to hours of work... |
why is the vision of spiders depicted as them seeing 8 of the same image as opposed to those 8 eyes merging the images together like human eyes? | Because that's literally how they work! It's called a compound eye, and it is comprised of many similarly shaped pieces that "see" independently from the others.
As a result, their vision looks like many repeats of the same image. It's actually incredibly useful because they see every tiny movement many, many times an... | [
"The spider has four eyes (2 small ones on the sides, 2 large ones in the middle), and is only the second known species to cephalopods to have such vision. The species are gray coloured with brown dots.\n",
"Spiders have primarily four pairs of eyes on the top-front area of the cephalothorax, arranged in patterns... |
what is that we see as happiness/love/desire/sadness/depression in someone else’s eyes? has then something physically changed in person’s eyeballs or how are those feelings manifested that make us to perceive them so effortlessly? | It's the combination of eyelids, cheeks, and eyebrows. Those three areas of the face are all very close together, and very slight differences in angle and tension can communicate a wealth of information about what the person is thinking/feeling. Cycle through a few emotions and feel how your eyelids shift, how your c... | [
"Neuroscience and brain imaging have shown increasing potential for helping science understand happiness and sadness. Though it may be impossible to achieve any comprehensive objective measure of happiness, some physiological correlates to happiness can be measured. Stefan Klein, in his book \"The Science of Happin... |
what would landing on a flying aircraft carrier be like from a physics standpoint? | Pretty much. Seeing as how modern aircraft carriers already move in 3 dimensions (bobbing up and down on waves and such.) The physics of actually landing would be pretty much the same.
The only likely problem would be trying to land in the dirty air created by whatever the carrier was using to stay up. Like in the Ave... | [
"In the Royal Navy, \"landing on\" is usually achieved by first lining up on the port quarter parallel to the ship's heading, then once the deck motion is deemed to be acceptable the pilot sidesteps the aircraft laterally using a white painted line (the bum line) as a reference.\n",
"Other aeronautical investigat... |
why is it that when you hit a dimming/dying flashlight it becomes brighter and lasts for a little longer? | I'm sure it has something to do with the battery connection.
On a lot of remote powered things, remote controls are a great example, if you take the batteries out and put them back in they work a little longer. Works if you just twirl the batteries.
| [
"While it might seem astonishing that so many longest-lasting light bulbs have been so infrequently turned off, this is the precise reason for their longevity. Most of the wear and tear that leads to burnouts in incandescent light bulbs is caused by turning them on and off, not by burning them. Each time the bulb i... |
why was there all this question about whether or not russia sent troops to ukraine in this day and age? is it really not that black and white when they claim thousands of troops and tanks? | Russia did not send their regular army in, and they didn't involve their air force or other branches of their regular army.
What they did do was allow volunteers from all over Russia and Europe (even some from western countries like France) to pass through their border with Ukraine and join the rebels. Many of these ... | [
"Initially, it was stated that the arrival of the Red troops in Ukraine was due only to the need for the advancement of Soviet troops on the Ukrainian railroad that were heading against the rebellious Russian Whites under Alexey Kaledin,which had occupied Rostov-on-Don on 15 December 15. In December 1917 the Lenini... |
why is the x86 architecture the only real force in the home computer market? | To find the real reason, we need to go back to the early 1980s.
IBM wanted to make a home computer. They had a choice of operating systems, and eventually decided to go with Microsoft (that's a story by itself, but we'll stick with the relevant stuff for now).
During the negotiations, though, Microsoft won a key conc... | [
"Modern x86 is relatively uncommon in embedded systems, however, and small low power applications (using tiny batteries) as well as low-cost microprocessor markets, such as home appliances and toys, lack any significant x86 presence. Simple 8-bit and 16-bit based architectures are common here, although the x86-comp... |
How much did America REALLY help in World War I | America's contribution was pretty much vital in terms of the war finishing in 1918. From the point of view of the Western Allies, things were actually looking quite bleak in 1917. For one, the French Army (who had shouldered most of the burden on the Western Front) was nearing breaking point (something that resulted in... | [
"The U.S. made its major contributions in terms of supplies, raw material, and money, starting in 1917. American soldiers under General of the Armies John Pershing, Commander-in-Chief of the American Expeditionary Force (AEF), arrived at the rate of 10,000 men a day on the Western Front in the summer of 1918. Durin... |
how do banks hold electronic money? | All banks must have accounts with the Central Bank (at least for US) but it isn't for the reasons you mention. Banks can simply debit and credit each other electronically without need for Central Banks to keep a record since each Bank will definitely keep a record of it (it is their core business!)
Banks must have an... | [
"Commercial or retail banks use what is known as core banking software which record and manage the transactions made by the banks' customers to their accounts. For example, it allows a customer to go to any branch of the bank and do its banking from there. In essence, it frees the customer from their home branch an... |
Why is it believed black holes preserve mass, charge and angular momentum, but not baryon number, weak isospin and lepton number? | Basically nobody has a fully quantum mechanically sound theory that relates to black holes, so people don't know whether they expect these things to be conserved or not.
I would say these quantities probably are conserved but don't affect the properties of a black hole. To an outside observer matter never even reac... | [
"Suppose two black holes have the same masses, electrical charges, and angular momenta, but the first black hole was made by collapsing ordinary matter whereas the second is made out of antimatter; nevertheless, then the conjecture states they will be completely indistinguishable to an observer \"outside the event ... |
why does methamphetamine use ruin your teeth? | It causes your mouth to be very dry due to reducing the production of saliva. Saliva helps keep your mouth cleaner and flush away sugars, acids and food particles. Without it, decay can happen much more easily.
Amphetamines can cause or worsen teeth grinding also, which may play a part. People on days long meth bender... | [
"Hydrochloric acid is used in methamphetamine's manufacturing process, but academic reviews have not supported the idea that the acid contributes to dental decay. Speculation that oral consumption of the drug causes tooth decay by raising the acidity of users' mouths is also unsupported. Meth mouth is generally mos... |
how do search dogs track scents? | Let's say they have a piece of your clothing. The dog is trained to follow a scent that is given to it, so they let it smell your clothing, then using its extremely acute sense of of smell it is able to follow the scent of the clothing you have on you. A smart criminal abandons any clothing it knows can be used to be t... | [
"One notable quality of detection dogs is that they are able to discern individual scents even when the scents are combined or masked by other odors. Many items that dogs can detect can be disguised when covered by multiple scents. Detection dogs help uncover these items. In 2002, a detection dog foiled a woman's a... |
In l’Hospital’s Rule, Why is the limit of a function the derivative of f(x) divided by the derivative of g(x)? Isn’t that like saying: to determine a person’s location you must know their speed? | L'Hopital's Rule has nothing to do with position, speed, or any physics whatsoever. First of all, it is not true that the limit of f(x)/g(x) is equal to the limit of f'(x)/g'(x). You need some conditions. The simplest proof is for the case when f(a) = g(a) = 0. Then we have
> f(x)/g(x) = [(f(x)-f(a))/(x-a)] / [(g(x)... | [
"which when taken to the limit as \"h\" approaches 0 gives the derivative of the function \"f\". The name of the expression stems from the fact that it is the quotient of the difference of values of the function by the difference of the corresponding values of its argument (the latter is (\"x\"+\"h\")-\"x\"=\"h\" i... |
the driving force behind evolution. | Evolution is based on the idea of "natural selection". Let me explain what exactly happens with DNA first.
Every living thing has DNA, which has a lot of pieces arranged in a certain way. The DNA is like a map for how everything is built. A human and a dog have DNA that makes sure they have legs, but a human has DNA... | [
"The term \"evolution\" was introduced into the scientific lexicon by Jean-Baptiste de Lamarck in 1809, and fifty years later Charles Darwin posited a scientific model of natural selection as evolution's driving force. (Alfred Russel Wallace is recognized as the co-discoverer of this concept as he helped research a... |
what is icann and why everyone is freaking out over the us ending their contract with them? | In short (I'm over-simplifying here) the ICANN takes care of internet addresses. This has been in the US for years, but after the NSA spying scandal they decided it was time to make some changes. See also: _URL_0_
It was always the plan to be global, and not tied to one specific country's government. It was never goin... | [
"On July 26, 2006, the United States government renewed the contract with ICANN for performance of the IANA function for an additional one to five years. The context of ICANN's relationship with the U.S. government was clarified on September 29, 2006 when ICANN signed a new Memorandum of Understanding with the Unit... |
What might the earliest human languages have sounded like? | We have no idea.
Some people are saying "Click languages!", based on [this](_URL_3_) research, which claimed to show that phoneme density went down the farther you got from Africa. But there were some serious methodological issues with that paper- mainly, their definition of "phoneme". Despite what we teach y'all in L... | [
"The discovery of Turkana boy (\"H. ergaster\") in 1984 evidenced that, despite its \"Homo sapiens\"-like anatomy, \"ergaster\" may not have been capable of producing sounds comparable to modern human speech. It likely communicated in a proto-language lacking the fully developed structure of modern human language b... |
What happened to the rail network of the US? | For the most part, it’s still around. The US doesn’t have construction of railways because we already have lots of them. All the big transcontinental routes you read about from the 19th century are, for the most part, still in place (with some adjustments).
There has been some contraction, though. There are two int... | [
"Railroads have been abandoned in the United States due to historical and economic factors. In the 19th century, the growing industrial regions in the Northeast, the agrarian regions in the South and Midwest, and the expansion of the country westward to the Pacific Ocean all contributed to the explosive growth of r... |
1) why is there gaps or spaces between galaxies? 2) what fills these gaps or spaces? 3) why aren’t galaxies connect like a web or something? | Galaxies *are* connected like a web or something [if you zoom out enough to see it](_URL_2_). It's important to note that the blobs of light in that image are *not* galaxies. They're *clusters* of galaxies, or superclusters, which can contain *thousands* of galaxies.
Consider the organization of the solar system. Most... | [
"When two galaxies pass by each other in close proximity, their shapes distort due to each other's gravity. The outside spiral arms splay out into space, often casting stars and dust into the abyss as their host galaxies drift slowly back towards each other in orbit. These spiral distortions are called tidal arms, ... |
Is there a certain density needed for gravity? | There is no theoretical minimum but (above and) below certain masses and (above and) below certain length scales there haven't been experiments. | [
"Unlike density, specific weight is not absolute. It depends upon the value of the gravitational acceleration, which varies with location. Pressure may also affect values, depending upon the bulk modulus of the material, but generally, at moderate pressures, has a less significant effect than the other factors. \n"... |
why dvd ripping is "not okay" and cd ripping is | The DVDs you have problems ripping are using [Content Scramble System](_URL_0_). This a system in which the video material is scrambled/encrypted, and the key to unscramble it is stored on a special part of the disc called the lead-in. When you put a commercial DVD in your player, it first finds the key, and then uses ... | [
"There are also DVD rippers which operate in a similar fashion. Unlike CDs, DVDs do contain data formatted in files for use in computers. However, commercial DVDs are often encrypted (for example, using Content Scramble System/ARccOS Protection), preventing access to the files without using the ripping software's d... |
How does Atomic Force Microscopy (AFM) works inside liquid? | I’m not exactly sure what you’re asking, but in general it works the same way as it does in air, but with some caveats.
In air, you scan the tip, which is at the end of a cantilever, over your sample. At the same time, you bounce a laser off of the back of the cantilever and to a detector, so that you measure what’s ... | [
"Atomic-force microscopy (AFM) is a powerful microscopy technique used for studying samples at a nanoscale and is often used to image protein distribution on a surface. It consists of a cantilever with a tip to scan over the surface. It is a valuable tool for measuring protein-protein and protein-surface interactio... |
Is the color red lucky in China because of tradition, or because Communism is associated with the color? | This question is not really a good question for /r/AskHistorians as this particular question is more of an anthropology question. That said:
Red as a symbolic color in China has always been considered culturally lucky and associated with joy way before the Communist Revolution in China. The color red is used a lot i... | [
"In China, red () is the symbol of fire and the south (both south in general and Southern China specifically). It carries a largely positive connotation, being associated with courage, loyalty, honor, success, fortune, fertility, happiness, passion, and summer. In Chinese cultural traditions, red is associated with... |
how it is not discrimination for offering race specific scholarships. | It is discrimination -- it's publicly acceptable (and completely legal) discrimination. | [
"The scholarship is open to students in all disciplines, including business, engineering, law, medicine, sciences, and humanities. There is also no discrimination on the basis of race, color, religion, national origin, gender, age, or disability in choosing awardees.\n",
"The Whites Only Scholarship was founded i... |
why do water droplets reflect their surroundings upside down? | The water droplets act like a converging lens. When you are close enough to a water droplet to see the reflection clearly, you are still outside the focal length, so the image appears upside down and stretched out. Were you able to get *very* close (and have there still be enough light to see), you would actually see t... | [
"The high surface tension of water causes droplets to assume a nearly spherical shape, since a sphere has minimal surface area, and this shape therefore demands least solid-liquid surface energy. On contact with a surface, adhesion forces result in wetting of the surface. Either complete or incomplete wetting may o... |
Regarding armed combat, was a dual wielding style ever used or maybe even advantageous? | Miyamoto Musashi was famous for mastering a dual sword technique if I'm not mistaken | [
"Dual wielding is using two weapons, one in each hand, during combat. It is not a common combat practice. Although historical records of dual wielding in war are limited, there are numerous weapon-based martial arts that involve the use of a pair of weapons. The use of a companion weapon is sometimes employed in Eu... |
Can mitochondria catch viruses? | "The self-destruction of cells infected with viruses undergoes the process of apoptosis generally to restrict infection and the spread of viral progeny. To avoid infection host has evolved interconnected complex defence network that comprises innate and acquired immune response. Mitochondria being considered as powerho... | [
"isolated mitochondria (from cell cultures, animals or plants); permeabilized cells (from cell cultures); and permeabilized fibers or tissues (from animals). In the latter two cases the cellular membrane is made permeable by the addition of chemicals leaving selectively the mitochondrial membrane intact. Therefore,... |
how red light therapy works | > Nothing about it makes sense to me. How does this work?
It is simple: Saps pay money for a red LED light and believe any pseudoscientific nonsense that is tossed their way. The scam artist makes a load of money off this fad.
Of course it doesn't do anything, there is no evidence that the "therapy" works, but that... | [
"Light therapy uses either a light box which emits up to 10,000 lux of light at a specified distance, much brighter than a customary lamp, or a lower intensity of specific wavelengths of light from the blue (460 nm) to the green (525 nm) areas of the visible spectrum. A 1995 study showed that green light therapy at... |
Why is thick ice blue? | For the same reason that ocean water is blue. Water and ice both [only absorb weakly in the visible spectrum.](_URL_0_) However this absorption is stronger in the red part of the spectrum and weaker at the blue end. As a result, the intrinsic color of water and ice is blue. The problem is that in order to see it you ne... | [
"Small amounts of regular ice appear to be white because of air bubbles inside them and also because small quantities of water appear to be colourless. In glaciers, the pressure causes the air bubbles to be squeezed out, increasing the density of the created ice. Large quantities of water appear to be blue, as it a... |
How is it possible to use flourine in toothpaste and how does it prevent decay? | Flourine vs flouride. Big difference!
Hydroxylapatite Ca10(PO4)6(OH)2 (I don't know how to do subscript on reddit, sorry) undergoes hydroxyl exchange with flouride to form flouroapatite. Fluoroapatite is much more resistant to acid mediated degradation. | [
"There are also many medications, which are used to treat tooth decay. Fluoride is used to prevent tooth decay in individuals. Fluoride is available in non-prescription form and is available in many different types of toothpaste.\n",
"Fluoride toothpaste is the most widely used and rigorously evaluated fluoride t... |
At which time did poland rename all their cities from German to Polish? Also, why did they rename them? | The current set of Polish borders are significantly different from the historical set of borders constituting what is "Poland". Poland existed as an independent state until 1795, when it was partitioned between Austria, Prussia, and Russia. Poland was revived as an independent state in the aftermath of WW1 but was then... | [
"All German names of streets, buildings, shipyards and districts, even names on tombstones, were changed to Polish names, such as \"Długi Targ\" for \"Langer Markt\" (Long Market), the city's main pedestrian center. The city districts were renamed, sometimes derived from medieval Polish records (Wrzeszcz, Siedlce),... |
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