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How to whistle without fingers?
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What I'm wondering is how one whistles WITH fingers, 'cause I've never understood how to do that. Only without fingers
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I can't do that. I just wanted you to know I both envy and respect your ability to whistle with your fingers
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How long does rope have to be to break under its own weight?
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That would depend on the material, the weight, and whether or not the rope has a uniform diameter. The tension in a free hanging rope is highest at the top. The rope's weight is its density multiplied by cross-sectional area and length. The tension in the rope equals the force divided by the cross-sectional area, or, length times density times g (9.81 m/s^2 ). Once the tension exceeds the yield strength of the material the rope will break, yielding L_break = sigma_yield / (g * rho).
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Every point on the rope will only be holding up the weight of the rope below it. So the only part of the rope that would experience the full 500 lbs of force is the segment of the rope at the very top.
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Why do people seem to get pain in their joints when the weather gets wet and cold?
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s8nlovesme is correct. Here is a source for a clinical research study pertaining to you question: _URL_0_ **Results:** Changes in barometric pressure and ambient temperature are independently associated with osteoarthritis knee pain severity.
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Your body has a system (the limbic system to be precise) that, when you're cold, compresses the capillaries in your extremities that pushes the blood to your torso and head in order to keep your vital organs from being damaged by the cold. When this happens your fingers and toes go numb and your torso is kept a little warmer. I'm guessing that in the water vs air comparison you're making the water is cold enough to trigger your limbic system and the air is not. I'm not an expert on this subject so someone might have a better explanation than I.
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Could chip companies add more chips to the bag?
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Most of what is in the bag is a gas such as nitrogen, rather than air, to help keep the contents fresh and prevent them from being crushed in transit. Adding more chips would make it more likely that they would be crushed. It's deliberate that most of the bag is empty.
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To avoid crushing your food. The packaging can be squished a bit until the pressurized air can support whatever is crushing it. If your chip bag was 100% chips it would be 1/3 crumbs.
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Why is H2O2 poisonous and H2O isn't?
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H2O2 is a highly oxidizing reagent because the O-O bond is relatively weak. It tries to oxidize anything that it comes in contact with to transform itself to low energy and stable water molecules. 2H2O2 ---- > 2H2O + O2
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It's _URL_0_ It's also somewhat poisonous to humans but we can metabolize ist faster and don't react to it.
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Is it possible to disapear with millions?
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not exactly millions, but D.B. Cooper managed a daring feat in this same vein by hijacking a plane, extorting $200K in ransom money (it would be $1.16M in today's money) and parachuting away, leaving no trace and never being seen or heard from again. _URL_0_
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I don't know if it directly answers your question but the [Copernican principle](_URL_1_) (see also: [doomsday argument](_URL_0_)) suggests that if it is possible, the simulation has already been created and you're in it. That is, either a simulation of the entire universe is possible, which suggests millions are possible since there would be simulations within simulations, in which case the probability of your particular consciousness finding itself in one of those simulations is much, much higher than in the "real," "original" universe, or (probably more likely) it's impossible.
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If the diameter of the observable universe is 93 billion light years, how can the universe only be 13.8 billion years old?
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The distance is not light-travel distance. The light was emitted 13.8 billion years ago, but at the time the (comoving, for those of you who want to be technical) distance was much shorter. The distances have grown considerably due to the expansion of the universe since the time the light was emitted.
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> I have seen it noted elsewhere that the expansion of space is not measured as distance/time (i.e., velocity), but simply as 1/time. Is this correct, and, if so, what does that mean? This would be the [Hubble constant](_URL_0_). This link claims that it's 71 km/s/Mpc (might be a little outdated). Since you have a unit of distance in the numerator and denominator, this quantity has dimensions of [time]^(-1), just like you said. But it's expressed in this way for convenience. I like to think of it as 71 (kilometers per second) per megaparsec. So if you have two points in space separated by a distance of one Mpc, then these two points are receding away from each other at a rate of 71 km/s. Also, you can take the inverse of this quantity (which has dimensions of [time]), and it will approximately tell you the age of the universe.
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If a UFO enters our atmosphere from outer space, why don't we see it light up like a fireball like when we see a meteor?
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Well, laying aside the obvious explanation that we've never had an extraterrestrial craft enter our atmosphere, the other reason is that meteors light up that way is because they're moving so quickly, [aerodynamic heating](_URL_0_) causes them to burst into flame like that. You see it on the space shuttle and capsules too, when they re-enter the atmosphere; it's a matter of speed is why meteors light up so brightly. They're moving *way* faster.
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If you look at the wavelengths of light that penetrate our atmosphere, they fall in the visible spectrum. We evolved to detect what "lit-up" the world IR thermal vision is really useful for hunting at night. We didn't do that though.
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Why does the sudden jolt of electricity, when plugging in your cell phone, not instantly, fully charge its battery?
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The movement of electrons through a system is what we call electricity. A batteries job is to store these electrons for later use. Electrons can have a wide range of speeds. A slow case: we know that electrons move when there is a current flow in a wire, but the speed at which the electrons themselves move in the wire -- the so-called electron drift velocity -- surprises most people. For example, for a copper wire of radius 1 mm carrying a steady current of 10 amps, the drift velocity is only about 0.024 cm/sec. So, basically the speed at which your cell phone battery is limited to the speed at which the electrons can travel through the wire on your charger. The larger the wire's diameter, the more current (amps) that it can withstand. You may think to yourself "ok, why don't we just make the wire bigger?" The more current you have going into a battery, the hotter it gets. This could then lead to battery damage, fire, or even an explosion. Hope this helps.
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It is due to several things. The most important is physical. During charging/discharging lithium atoms move from one electrode to the other. The lithium goes into tiny pores in a sponge like electrode, but when this happens the sponge swells up. Repeated swelling and shrinking eventually causes cracking and fractures in the electrode, degrading it. The other main effect is chemical reaction in the electrolyte. During charging, tiny amounts of electrolyte material undergo unwanted chemical reactions with the electrode chemicals. Eventually the electrolyte gets polluted with all the byproducts of these reactions degrading it.
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Why is the housing market such a major factor in the economy?
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Because, for most people, a home is the most expensive thing they'll buy during their entire lives. And everyone needs one. It's a basic need like food and clothing. So, when people are buying homes, and there's a demand for new homes, an economy is generally growing because people are willing to spend money which in turn means people are employed and earning and contributing to the economy. Building homes also require an army of workers which further drives an economy by employing more people, opening different industries, etc. New housing schemes/subdivisions also require service areas, business parks, schools (teachers), etc. So you see, a growing housing market is a good indicator of a growing and thriving economy.
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Think of it the other way around... Fewer and fewer people can afford new houses/apartments *because* prices keep getting higher
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You probably have seen a life-hack tip on exiting a maze. It says (real or in game), just keep right and you'll get out. Why is that?
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Well, it's not always true. If there are any closed loops of walls in the maze, you can get stuck on the wall and not get out. But this method will keep you on the same wall and not retrace your steps until you've gone everywhere that wall goes - and if there are no closed loops, that wall must lead to the exit eventually.
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Mazes are generally designed in one way, especially kids mazes. The dead ends are easily to end up in as they aim towards a likely finish point. Going the other way, backwards, the dead ends will aim also backwards, and be less tempting to take to get to the outlet (start, if backwards). I drew an example but reddit does not support single page breaks. Hopefully my answer alone makes sense.
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Why do hurricanes weaken over land, while incredibly strong and violent tornadoes can form and sustain themselves entirely over land?
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Tornadoes are localized wind vortices that form around storms or weather fronts. Hurricanes are weather systems that increase in intensity when warm most air rising off of a body of water strengthens the convection within it. Land does not provide that warm most air.
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I have no idea about the physics behind it, but I've always learned that hurricanes gather strength while traveling over relatively warm water. And the hurricanes that regularly hit the east coast of the U.S. originate as specific wind patterns over the Sahara desert in Africa.
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When driving, why do different types of pavement sound different/louder than each other?
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It has to do with 2 things, your tires (pattern and depth) and the density/thickness of what your driving on. The interstate for example is very thick and packed densely, with foundations of rock and gravel, and then paved very thick. This makes it strong (holding up constant weight and being driven on) and quiet compared to inner city roads or country roads were laying that type of foundation isn't feasible or cost effective. Think of it like a xylophone, hitting bars of different thicknesses make different tones. Thicker bars will make a deeper and shorter tone whereas the smaller ones make a loud and longer tone.
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The reason for road noise is actually pretty complicated and can be caused by a number of factors. The more common reasons are the smoothness and resulting friction on different surfaces, the texture of paving material on a surface, and the flexibility of the material used. A coarse, hard, and friction inducing road surface like poorly laid concrete produces a ton more road noise than, say, new "black-top" using a combination of binders (like tar) and finely crushed rock. Then again, your tires also play a huge role in noise produced, which is a reason town tires were originally developed. EDIT: Source, studies included: _URL_0_
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Do 'ultrasonic' insect repellents really work?
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The short answer appears to be no. I researched this a while ago when I heard about them and my BS meter went off. I found [this](_URL_0_), which unfortunately doesn't actually directly link to the studies. It seems that they will work on crickets, at least until they get habituated to the noise and ignore it. Apparently the FTC even warned companies that produced these devices that they need to back up their claims, with one company even being sued for violating the warning.
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Bugspray is actually a chemical weapon. As in it shuts down biological functions bugs need to stay alive, like forgetting how to breathe for example. It can also cause military chemical weapons detection gear to register false positives.
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Walking barefoot in the library at my college, I was just told by a janitor that I shouldn't do that because of all the chemicals they spray on the floor (to remove stains, etc.). In truth, how susceptible are my bare feet?
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Janitor here so I can tell you that it depends on the chemical being used. If he told you not to do it though he's probably right. Most janitors are trained in at least some basic hazardous materials handling because we tend to have at least one or two chemicals we have to use on occasion that can fuck you up. For example I've had to use a concentrated floor sanitation chemical that will give you chemical burns if you get it on your skin. Some of the serious sanitation chemicals require you to wear a mask or even a full respirator because of what they can do. If this was in a library chances are it was nothing like those, he was probably warning you because the stuff he was using could irritate your skin (like walking on freshly fertilized grass).
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If you cut your foot walking barefooted down the street, you can't sue anyone. If you do the same thing in a restaurant or shop, you can sue them. That's the differences. Also, you know, other people in said shop don't always want to be subjected to your bare feet.
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What makes your voice crack?
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Your vocal cords become bigger during puberty. The longer they are, the deeper your voice is. It's kind of like a guitar string; the longer the string, the lower the sound. During puberty, when your voice drops, your vocal cords are slowly being stretched out and elongated. However, they occasionally spasm, leading to voice cracks. You may notice that when other muscles are tired (e.g. after working out), they may spasm more. This is also why your voice will crack more often when your voice is sore, like after shouting a bunch.
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Your voice mostly comes from your voice box (or larynx). Talking or shouting too much, will scar or damage the tissue in your voice box, causing it to inflame, or swell up. Because of that, your vocal cords won't vibrate properly, giving you a harsh sounding voice, or none at all. Further reading: The condition of losing your voice is called [Laryngitis](_URL_0_)
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Why do gaming consoles use A B X & Y on their remote controls.
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Very early consoles usually had a direction pad (D-Pad) or a joystick and two buttons, which they labeled A and B. Later, some added a third button (C). When they wanted to go to four buttons, it would have made sense to use ABCD, but D was already sort of taken (since everyone calls it a D-Pad), so they went to the opposite end of the alphabet. (Where did Z go? Judging from [this Sega controller](_URL_0_), it was there, but they dropped the far outside buttons.)
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That's called a computer. But seriously, I suspect it's to perpetuate a divide between computers and consoles so console buyers don't think they're just buying lame computers.
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How did Ernest Rutherford know that the the positively charged particles in a nucleus were equal in magnitude of charge to electrons?
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Rutherford was influenced by Prout's hypothesis that all atoms were made up of groups of hydrogen atoms, with the hydrogen atom being the fundamental particle. The logic was that the atomic weights known at the time were almost exactly integer multiples of the mass of hydrogen. If there were smaller particles, there would be smaller elements or elements with masses that fell in between multiples of hydrogen. Obviously Rutherford discovered that an atom wasn't just one particle but a positive nucleus surrounded by negative electrons, and then when he observed the process of nitrogen atoms releasing hydrogen atoms when bombarded by alpha particles he took this as evidence that the hydrogen nucleus is indeed the fundamental building block for all other nuclei. This was before the neutron was discovered, it was believed that the nucleus was only made of positive charges. Of course, protons are actually made up of quarks with fractional charges but there was no way to know that at the time.
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Rutherford proposed a neutral object in 1920. He wanted to account for the difference between the atomic number and the mass number of atoms. A neutral object could do that. Edit: I should add that Rutherford did not originally anticipate that this would be a brand new particle, but conjectured a neutron that was a combination of a proton and electron. In this latter piece of his conjecture, he was wrong.
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How does the body "know" to enter puberty after a dozen or so years?
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The exact timing isn't completely understood yet but there are a few likely theories. Genetic factors are said to have a part in it, thus you could say the timing runs in the family. A gene known as [GPR54] (_URL_0_) encodes a protein that indicates a normal release of hormones during puberty. Another theory would be that our bodies enter the phase of puberty upon reaching a certain amount of bodyweight. The process has been noted to begin earlier for overweight children but it's likely caused by multiple factors.
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You'll need to state what you mean by maturation. On average, girls enter and leave puberty before boys, so that could be seen as support for the notion that they mature faster. By the way, you're asking about a hypothesis, not a theory.
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If a supernova from a star was racing toward us, would we know before it hit us?
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It depends on the type of supernova. A type II supernova releases a burst of neutrinos a few hours before the light leaves the explosion so if you have a neutrino detector you would be alerted a few hours before you see the light from the supernova. In fact, there's a website that will send you an email if such a burst of neutrinos is detected.
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I'm confused... There have been observed supernovae since then (e.g., 1987A)
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Physics of a remote control helicopter in a car
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No. This is why we wear seat belts. This is just simply mechanics. The helicopter is floating in an inertial frame along with the air in the car and, at least initially, the car. Let's say everything is traveling at 60mph relative to the street. All of a sudden the cars starts decelerating. From the helicopter's frame, the car goes from stationary to -60mph. The window smacks the poor helicopter in the face.
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Found an explanation [here. ](_URL_0_) In short, no it would not. The helicopter is still under the same momentum generated by the rotation of the Earth, so it would move along with the Earth in rotation unless the pilot exerts a force to counteract this movement. It's the law of inertia, and the conservation of momentum. The helicopter will continue in the same rotation as the Earth unless there is a horizontal force on the helicopter that changes that momentum.
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When did "Cowboys" become famous?
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It really begins with the explosion in [dime novels](_URL_0_) following the American Civil War. Initially, most of these would've been about [Mountain Men](_URL_2_) or trappers moreso than cowboys, but with rail expansion came an explosion in the livestock trade, so that ranching became the prototypical western occupation. The lawless, frontier nature of the West is a natural breeding place for drama, and the antics of the notable lawmen and outlaws of the late 19th century made for great pulp fiction, further growing the mythology of the old west. [Buffalo Bill's Wild West](_URL_1_) show really capitalized on an interest that already existed, but it played an important part in cementing the Wild West archetypes in American consciousness.
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Yes, we still have many of the recipes that were made on the trail, in fact in parts of the country cowboys never stopped cooking their trail recipes and there are even [competitions today for best chuckwagon food](_URL_0_). There are books that have compiled authentic trail recipes ([recommended reading section](_URL_1_)) and [newspaper records of recipes](_URL_2_). As long as you aren't a vegetarian and you may find most of them appetizing, since meat is one of the ingredients a cowboy was practically never far away from.
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How often would an army in the Middle Ages actually see combat?
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That question brings up an interesting point. Armies in the Middle Ages were largely feudal (speaking of Europe and the near east) and thus would not be assembled at all unless conflict and war loomed. That said, there was great variability; states such as Byzantium employed professional standing armies that remained constantly mobilized and ready for combat. The Byzantine army, however, was only used as a last resort; the emperors preferred complex diplomatic and political schemes to outright warfare, so in that sense the army saw less combat than it would have otherwise. The feudal armies of western Europe were assembled for specific goals (invade this country, capture this fortress, etc, etc) so in that sense they were more likely to see combat. Hope this was what you were looking for!
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Probably would be better for you to specify a time and place. Late Medieval is a bit subjective and definitely would vary based on where you're talking about, as would the warfare.
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Why did intelligence only evolve once?
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It is incorrect to claim that intelligence only evolved once. There are many intelligent species from different branches of the tree of life. Primates, dolphins, elephants, dogs, and even cephalopods are arguably intelligent to some extent. Humans certainly take that particular trait to an extreme, but so what? For any given trait you can think of, there must be one species on earth that is the most extreme example of that trait. Humans are the species that takes intelligence to its furthest extent, but we are definitely NOT the only species in which intelligence has evolved. You are claiming that humanity is somehow qualitatively different from all other animals - that we have something that is not found even in the smallest quantity in other species. The data do not back up that assertion.
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Yes. There's been plenty of time for intelligence to evolve, though we are the first large-scale technic species to inhabit Earth it would be impossible to definitively deny any intelligence evolved before us. That, of course, begs the question "what is intelligence," and we don't really have an answer for that. We can't effectively measure it within our own species, much less between them. However, as far as we can tell humans have been anatomically modern for only a few hundred thousand years. There's no reason that an abstract quality that can be defined as intelligence couldn't have developed before us (in a case of convergent evolution). Just so far as we know, it didn't.
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How come in a can of soda or beer, the bubbles don't all either rise to the surface or sink to the bottom? How do they remain dispersed throughout the drink?
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It's because until the pressure is released when you open the can, the bubbles don't exist at all. The CO2 is dissolved in the water, but when you release it, the CO2 can finally escape and it becomes bubbles.
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No. In fact, quite the opposite. The bubbles are carbon dioxide gasses held in suspension in the soda by high pressures. As the pressure increases, more gas dissolves. Squeezing then capping the bottle puts negative pressure on the liquid, causing the gas to fall out of suspension faster.
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The crust of Mercury was recently found to be magnetised. Does this conflict with current models of planetary evolution?
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We have remnant magnetism preserved in our own crust - the oceans are striped with different polarisations of remnant magnetism as they extended and our poles repeatedly reversed. All it tells us is that Mercury's crust is probably largely mafic (basaltic) igneous. That artilce tries to correct a quote and gets it horribly wrong in the process. Everything they infer from that point on is flawed.
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The amount of magnetism induced in a material depends on its magnetic susceptibility, with some materials being much easier to magnetise than others. Mercury is what is known as a diamagnetic material, which means when exposed to an external field it gets magnetised in the opposite direction to the field, but its susceptibility is extremely low. For comparison, it is only about 2-3 times larger than water, and around 1-10 billion times weaker than iron. Similarly, the types of steel that are used in braces (stainless steels of the 300 series) are also comparatively non-magnetic when compared to standard steels and pure iron. Simply put, any forces or currents that are induced in the mercury are extremely weak and will go unnoticed by us.
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how do diseases get their names?
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Some diseases have had old world names that stuck around due to just the convenience like malaria, literally Italian for “bad air.” Some names like Syphilis used to be called “The French Pox” but for obvious reasons got thrown out and replaced with a less controversial name (named now after a fictional character with the same namesake). Finally you get stuff like HIV, which literally is what it is, Human Immunodeficiency Virus.
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* disease - a dysfunction in the body, can be used to specifically refer to those caused by an infectious agent * disorder - a dysfunction in the body, can be used to specifically refer to those **not** caused by an infectious agent * syndrome - a set of symptoms commonly associated with each other, often used as a placeholder term until the cause is better understood There is a lot of overlap between these terms for historical reasons. With a syndrome that has been around for a while, like Down syndrome, that term might continue to be used even if it more properly could be styled a disorder. Similarly, some disorders are later found to be caused by infections but keep their names.
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What is the purpose of fashion shows?
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They show the overall direction and concept behind a designers new line of clothing. For the high fashion type shows where the models are wearing what appear to be ridiculous outfits, those aren't to show off the clothes, but rather the themes and directions the designer's clothing will have. A great way to think of a fashion show is to compare it to an auto show. When Ford or VW show some crazy looking car with extreme features (a concept car), it's understood that they don't plan on making that car, but are rather using it to show the direction they're taking their design (sharp angles, rounded off, bubbly, aggressive, whatever). So a fashion show is when Armani or Burberry or whoever display where they're going with their overall design concept for the coming year.
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The simple answer is that it's fun. A lot of people like to get artistic with their costumes and have fun dressing up with family and friends.
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Why does a balloon feel like it loses helium while I hold it tightly, then regains that "lost" helium as let the balloon fly freely?
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The pressure, and therefore volume, of gases varies based on a few factors, especially temperature. Most of the time it is colder in the morning and warmer later in the day, so the balloon shrinks as the gas has less pressure when it is cold and then grows as it get warmer. It has the same amount of gas, but the gas is taking up less space. Think of taking cotton candy and squishing it down. You are reducing the size, but not the actual amount, of the candy. And yes, you can squish it with your hands to, but when your hands aren't there to squish it down, it returns to its normal volume.
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Even though you can't see it, there are tiny tiny holes in the balloon that allow the air to escape over time.
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Why does a developed country like Canada have poor (mobile phone) reception(/network/signal) problem even in their major cities while a developing country like India has excellent cellphone reception even in small villages!?
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economy of scale. also reluctance to invest due to lack of economy of scale in Canada. also duopoly between bell/rogers/shaw/etc networks so they have little reason to compete. Also lack of competition. Also the government pays incentives to the companies more to focus on providing cross-Canada coverage; it pays no incentives to improve local service. It's a cost-return thing. If you put up more towers in the urban centres you're not getting more clients anyway. And since there's no competition.... Just play with the variables above and you'll find quite the same results as the large companies. They just see no financial reason to improve service in Canada.
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Cost. It's cheaper to build a smaller number of antennas in locations that allow sharing -- this usually means putting them high up so their signals can get past obstacles. One phone antenna tower may serve users across up to 100 square kilometres. (Typically fewer, but still a large area.)
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How does tin foil in the oven not get hot?
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It does get hot. But since it is so thin, it has very little mass and a very high surface area compared to that mass. So by the time you've pulled it out of the oven, it's already cooled down quite a bit. That very low mass also means there is not much actual heat energy stored there to burn you.
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The cooling rate of an object increases the more surface area it has. The heat energy stored in it increases in proportion to its mass. Aluminum foil has a very high surface area and a small volume, so it loses its stored heat very quickly.
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After getting obliterated during two world wars, how has Germany been able to go back to being a world superpower?
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The damage done to Germany's economy in WW1 was one of the major causes of Hitler's rise to power & starting WW2. After we won WW2, we realized that leaving a country in shambles might *not* be the best thing for stability in the region so the Western powers put a lot of time & money into rebuilding West Germany and making it the sort of strong democratic country that wouldn't readily fall into fascism in the future. It's very similar to what happened in Japan. _URL_0_
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The German government essentially directed German industry to produce for the military and Germany stopped paying reparations in 1931 and didn't resume until after the war. Also, the great depression certainly leveled the playing field a lot between Germany and France and the UK in terms of industrial production.
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How are panic attacks and anxiety attacks different?
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Anxiety attack is not a clinical term, whereas panic attack is. People can experience panic attacks with or without a precipitating event. Panic attacks tend to be short lived, around 30 minutes. They tend to make the person feel as if they are in imminent danger of losing all control and possibly even of dying. Source: DSM as reported on Wiki. Since anxiety attack isn't a clinical term, its use depends on who is saying it. I use the term to refer to episodes I have where my anxiety increases exponentially over my normally high levels and leaves me non-functional, lasting anywhere from a few days to a couple of weeks in extreme circumstances. In my case there is always a precipitating event. But that is my usage of the phrase. As I said, it's not a clinical term. Some people use the terms panic attacks and anxiety attacks to mean the same thing. I personally don't because I have a friend who has true panic attacks and don't want to confuse her.
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Panic attacks are a very interesting example of the effect of our thought process in our bodies. It can be triggered by a small stimuli. Like brief dizziness or chest pain that by itself is nothing of importance. But the patient gives this event an importance much greater than what it really is. This creates anxiety and stress. Here is where it starts to escalate, the anxiety and stress generate a physical response. This mental states for our body mean that there is some danger we must escape so we start pumping large amounts of stimulants (adrenaline, noradrenaline) into our system. These have many effects, the patient perceives them and attributes it to the same pathology as the one causing the initial stress and anxiety. Of course this causes more anxiety and in turn a sustained release of adrenaline. At this point the patient thinks he is dying which perpetuates the process.
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If you boiled salt water then collected the steam vapor could you healthily drink it?
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Yes, in fact this is the most commonly used method for water desalination and is practiced on industrial scales, especially in places like the Middle East, where water reserves are very scarce. The most common way that desalination is carried out industrially is via what is called flash distillation. The basic scheme is that you first pump in salt-water, you then heat it up (usually at reduced pressure), and finally you collect the steam and allow the water to re-condense. Usually this process is done in several stages (e.g. [as roughly shown here](_URL_0_)) simply because doing so is more energy and cost effective than simply distilling the water in one step. The vast majority of the water processed via desalination is obtained using some variation of this scheme.
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Assuming that there is no loss at all, then it would just pressurize because this would have to be an isochoric system. However, given that this is purely a thought experiment, then for the sake of argument, sure you could boil water by shaking, but it depends upon your shaking frequency and magnitude. It is just a quick calculation on the mechanical energy of the shaking because all of it is converted into vibrational energy from friction and thus increases the temperature of the water.
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Offspring Selling Their Catalog for $35 Million
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For the most part, this is a normal business transaction. The Offspring think that $35M now is worth more than whatever future revenues their old catalog will be worth going forward. It could be a variety of reasons, for example, people in offspring need some cash now for whatever, it may be worth more, but getting paid out a bit more than $35M over 20-50 years when you need money now isn't too helpful.
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Who bought what product from which production run at what time from which store, and where they live if they ever want to sell something else (or sell the list of customers).
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Why are the health benefits of sunlight not replicated by other light sources?
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Actually, there are lamps that stimulate vitamin D... They're marketed for treating Seasonal Affective Disorder (SAD) and they mimic the spectrum of light from the sun
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The sun puts out visible light that we can see, it also puts out light we can't see called ultra Violet or UV light. Our skin absorbs the UV light which causes damage we can see and feel as sunburn and eventually cancer. Sun screen is a combination of ingredients including metals like zinc or titanium which reflect most of the light away from our skin instead of allowing it to be absorbed. And organic chemicals which absorb the UV light before it can get to our skin It's like a camouflage to hide our skin from the UV light.
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What allowed the German Empire to hold the western front and some of the eastern front for so long if the narrative that their military was amazing is overstated?
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I won't claim to offer a full answer to this, but one key factor was that their generals were far better (for the most part) than those of the Entente. The German military was essentially the old Prussian military with the best of the smaller German states such as Bavaria, Saxony, etc bolted on. They had been planning the attack on France since almost immediately after the Franco-Prussian war, correctly assuming the French would want that land back. In the west they were able to move quickly enough to seize the initiative and the strategically important ground time and again. British soldiers were noted complaining that the Germans always had the high ground and their own trenches were always on the low ground, so they'd often be knee-deep in muddy water and contract disease much more often. Even if their technology was a behind and their commanders weren't the best at adapting to circumstance, they still had that reputation. Perhaps an overblown one, but even a lie can scare the enemy.
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To clarify, do you mean what the German Empire in 1914 and before expected to come from fighting World War 1 or what the German Empire during 1918 and beyond thought was going to happen after the war?
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In US history the Confederate States are often seen as the bad guys. What's the truth?
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The scholarly view is that the majority of white people on both sides were racist, that neither side was silly, and that the Confederates were led by white southerners whose primary objective was to protect and expand slavery.
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East Tennessee was maybe the largest, most unionist part of the south below the 36th parallel. East Tennesseean insurgents burned bridges, confederate soldiers hanged east Tennesseeans. There's a book in a Baptist Church in Cades' cove in which someone wrote that they have not me in the church during the war to avoid harassment because 'we was union men'. Source: Battle Cry of Freedom, McPherson
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Why do we sometimes have to gag when we only see disgusting things?
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Because you have an evolutionary incentive to do so. Your ancient ancestors had an omnivorous diet of fruits, nuts and meat where they could find it. Imagine you see that the inside of a carcass you're eating is rotten and full of maggots. Gagging is your brain telling you to eject the contents of your stomach to avoid poisoning yourself. This is also the reason why you feel the need to vommit when someone else does. You may have ingested the same poison. After all, if that ape is near you then they're probably in your group. And you're probably eating the same thing they are. Therefore better safe than sorry. Sure...you may lose the contents of your stomach, but it's better than death.
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It's actually part of an ingrained disgust system. It mostly involves taste and smell, but some sights we associate so strongly with disgustingness that it can trigger the response too. Generally speaking, things that taste/smell disgusting are things that can cause illness - poisonous berries, rotting meat and so on. Obviously, this kind of thing is going to damage the body if we get infected by it, so we have the vomit response - purge the stomach contents and you remove the ingested poison from your system before it can do any more harm. When we feel sick while infected with something, this is also the vomit response trying to prevent additional harm being done by anything in the digestive tract. Visual disgust I think is more of a subjective system, a learned response. For some reason you've learned to associate a certain *sight* with bad things. Unlike smell and taste vomiting this is likely not an evolved trait.
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How does quickscoping work and why does it still exist in recent games?
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When you aim with a sniper for a split second there is a huge amount of aim assist that pulls towards the target. More than normal.
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> the cheap water pistols (a trigger pull) This kind of water gun works simply by using the trigger pull as power for a simple water pump, basically a plunger to force a small amount of water out the narrow nozzle. > stuff like Super Soakers This kind actually pumps air into the airspace of a water reservoir. The built up compressed air pressure will push the water out of the reservoir and through the nozzle. > And is there anyway to make it "rapid blaster"? I'm not really sure what this means. Is that a specific water gun you are asking about?
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Why is the "Sexy Son Hypothesis" presented by Prof. Richard Dawkins scientifically substantiated?
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> Why is the "Sexy Son Hypothesis" presented by Prof. Richard Dawkins scientifically substantiated? This sort of sounds like a loaded question as it assumes the hypothesis is "scientifically substantiated", whatever that means. The general idea is that the most important aspect by which a female would choose her mates is the chances of the male to produce promiscuous male offspring. Female offspring of the female are only going to be able to pass on their genes once every breeding cycle, while conceptually a successful male could do so many times with different females per cycle. Therefore a female would be selecting a mate based on their ability to produce a "sexy son" as opposed to a "sexy daughter".
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There's a lot of rumors and speculation about whether or not Michael Jackson is the biological father of his children, but it's not really ELI5 material. There's no officially confirmed facts and no actual reports of science involved, so there's nothing to really explain to you. But you're not alone in wondering about it, at least. There's a large community of celebrity gawkers who frequently gossip about it.
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What do I smell exactly when something is dead?
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The decomposition and putrefaction of biological material is associated with a number of different compounds, which give off the characteristic smell of death and decay. These compounds include: hydrogen sulfide, ammonia, [cadaverine](_URL_1_), [putrescine](_URL_0_), [skatole](_URL_2_), and butyric acid.^1 --- 1) Gennard D. Forensic Entomology: An Introduction. Wiley-Blackwell: 2012.
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The bodies have long passed the smelly portion of decomposition. A freshly rotting body produces a ton of smelly gases as bacteria eat the flesh. A dry pile of dust and bones doesn't produce much smell since there is very little bacteria eating it.
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Why is it that certain character cannot be used in the naming of files on Windows computers?
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Back in the days of MS-DOS (Microsoft Disk Operating System) those characters were used in the command line for telling the system what to do. Changing a to a tree in the directory was something like 'cd c:\Reddit Been a long time, but that's close.
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This is not obvious when you use GUI explorer. But it it obvious when you start using command line / shell. Those symbols are used as syntax/commands within the shell. So if file contained those symbols, the shell would not know if that symbol is part of file name or if it is part of command.
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Why do celebrities, particularly actors and actresses, make so much money? When did this become a common practice?
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Well you see, people like to watch movies So, when a movie comes out, millions of people might pay money to see it That means that big movies make 100’s of millions of dollars A small part of that 100’s of millions goes to the actors as payment for their work. But, even a small part of 100’s of millions of dollars is still a LOT of money, so big actors who make big movies can make a lot of money.
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The biggest expense in a Hollywood movie are people expenses. The stars get a big part of the price of the film, usually at least half the budget between top stars, co-stars and the rest of the cast. The screenwriter(s), director, and producers get a big chunk. Everyone who works on the set is paid a union-scale wage; the gaffers, cinematographers, makeup, riggers, etc. A big special-effects film will pay an army of people who do modeling, art, animation, motion capture, and building customized tools. Sit through the credits of one of these films and you'll see and endless list of people who do this work. These are pretty good paying jobs, and the work can last six months or more. Then there are rentals for equipment, payments to use exterior and interior locations, royalties for licenses, food service, travel and lodging, and overhead for lawyers, accountants, security, "personal assistants", etc.
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Nuclear power plants, how long could they run by themselves after an epidemic that cripples humanity?
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There was a similar question that was answered in the book 'What if' that went along the lines of if all humans disappeared, what would be the last light (source) that would turn off. When he answered, he mentioned that anything running on electricity won't last more than a day (if running from a nuclear power plant). These plants will turn off any production of electricity if there is no human intervention (I think it has to do when the cooling water boils off)
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An nuclear explosion is impressive-looking, but ultimately the energy-content is pitiful, compared to that of the global circulation. [The thermal energy from a single mature hurricane equates to a 10 megaton nuclear explosion every 20 minutes](_URL_0_). The impact of a single hurricane on the global climate is incredibly small, so you can imagine how small the impact is from nuclear tests.
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What city has been occupied/destroyed/burned/blighted/ruined the most times?
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I would say that probably cities that have been occupied, burned, blighted ect.. the most would be found in Mesopotamia. This is simply due to the sheer amount of time they were occupied for. Uruk for instance was occupied from 4000 BC to the Hellenistic period (200s BC) and Eridu was perhaps occupied from 5400 BC to the late iron age (6th century BC) These cities fought each other constantly and became part of many empires during their archaeological history, empires such as the Akkadian Empire, Ur III, the Babylonian Empire, the Neo-Babylonian Empire, the Assyrian Empire ect... Alternatively it could as mentioned very well be a city like Jerusalem
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You might find u/Tiako 's top comment from this thread 4 days ago to be an answer to your question; [How do cities die? - /r/AskHistorians](_URL_5_)
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Are NASA spacecraft transmissions encrypted?
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This varies. In the past, information was transmitted in the clear. This reduced complexity and thus increased reliability. You would still need to figure out the communication protocol and/or file formats to understand what the information means. However, there were several incidents in 2007 and 2008 when someone (not NASA) took control of a LANDSAT satellite for a few minutes. It is thought that the Chinese were responsible. No harm was done to the satellite. Of course, NASA now has a focus on secure satellite communication. See _URL_0_ page 215-217, for information on the Chinese attacks (hacks?) on satellites.
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The voyager probes have a large dish antenna, capable of sending a signal nearly 10 times stonger than a mobile phone but focused in the direction of the earth. However by the time the signal arrives at earth its power level is 20 billion times lower than a digital watch battery. To counteract this NASA have a system called the Deep Space Network, comprised of massive directional radio telescopes measuring as much as 70 metres across. They spend hours pointed at the voyager probe listening for the faint signal amongst the background noise. The mars rovers can also communicate with the Deep Space Network, but they can also use probes orbiting Mars as relays
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Just got Minecraft recently and I was wondering what texture packs were and what they did?
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Texture packs are basically the skins of everything you see in-game. When you change a texture pack, the look of the block types will change (dirt, cobble, sand, even non-blocks like flowers, rain, mobs, etc). Since you just got MC, the texture pack you're using is the Default one.
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Packaging. I wrap my stuff in plastic wrap, then foil, then a ziplock baggie and I never get it.
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What stops large nations from annexing smaller micro states beyond international backlash?
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Why would you want to? The real world isn't a game of Risk. If China wanted to annex Vietnam or North Korea, it absolutely could, but to what gain? The populations in different countries are distinct, and they may gain an insurgency, ethnic unrest, new problems, etc. Why do that when you can just sign trade deals, alliances, etc. with the smaller countries, achieving some good things--bigger profits from trading, security--without the headache of administering a foreign country.
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They are slowly annexing the favorable territory in West Bank in the hope of eventually incorporating much of this territory as Greater Israel. The secondary goal is to prevent a viable Palestinian state in the West Bank by leaving them only the worst land, much of it fractured from one another and effectively ungovernable.
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Why doesn't a moving charged particle exert a magnetic force on itself?
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In the rest frame of the particle, there is no magnetic field.
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The magnetic field interacts with the electrons and "drags" them with it.
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How did Greece get from saying "No" in their referendum to passing an Austerity Bill in under 2 weeks?
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If you look at the referendum question, the [phrasing was not a simple yes/no to austerity, but a rejection of a specific proposal by the EU](_URL_1_). The bill that has been passed is a fresh proposal put forward by the Greek government themselves. So whilst not technically being a violation of the referendum result, essentially the government has caved to pressure from Europe to avoid being kicked out of the Euro entirely. But as you might think, [there are plenty of Greeks who feel that the referendum was pointless, and that the new austerity bill is worse than the one they rejected](_URL_0_).
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The party currently in power promised end the austerity measured imposed on it by the EU, and it promised it would no leave the euro. It will have to break one of those promises. Note that Greece has always had the option to honor the existing deal, and get additional bailout money. They current gov't doesn't want to, because they feel that honoring validates it, and it breaks the main promise they used to get elected.
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Who was held responsible for the titanic sinking?
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Despite multiple inquiries - the Senate in the US and the British Wreck Commission - and hundreds of witnesses examined, ultimately, the disaster was essentially declared an act of god. While regulations about the number of lifeboats changed, the White Star Line had met the minimum requirements of the law. While Captain Smith did not take enough heed of ice warnings, or the loading of the boats was chaotic, etc, etc, in the end... nobody. Nobody was held responsible. If you are curious about the aftermath of the Titanic disaster, or how society reacted to it, I strongly recommend Steven Biel's "Down with the Old Canoe" - it's a solid read.
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The captain is responsible for everyone on the ship. If the ship sinking it is his responsibility to get everyone to safety, That means he stays in command until either everyone is safe or there's no more ship to command.
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Why would you use shaving cream to clean a grade school desk?
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Kids like to make a mess. It lets off steam and lets them get one over on the adults. Teachers like it because it keeps kids occupied and gets the desk clean. Win/Win for everyone.
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It lubricates the skin so that the razor blades slide across instead of getting caught in the skin and causing nicks. You can use soap or olive oil to achieve the same effect, but shaving gel/foam was created expressly for the purpose.
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Why am I sleepy and tired during the day but hyperactive and exited during the night?
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Because your body is off schedule. Until you are on schedule, it will be like this. Here is how you fix it: * Wake up at 6:00AM every morning (including weekends) * Do not nap during the day * Get a decent amount of exercise each week After you do this for a few weeks, you will magically have lots of energy during the day and magically be dead tired by 10PM.
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There's a whole slew of factors, ranging from individual adenosine (neurotransmitter) levels (which peak during the evening, in response to processes of energy consumption throughout the day), melatonin levels (a hormone which regulates the sleep-wake cycle) and ambient light levels. An imbalance in any one of these factors (and many, many more) may cause a person to wake. Ambient light level is often the strongest of the factors listed above.
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How can some people with really, really thick glasses lenses wear thin little contacts?
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1) smaller field of view. Contact lens only have to cover your iris. Glass lens are curved over the entire glass, so that you can still see clearly when you move your eyes around. 2) contacts are closer to your eyes, so the corrective portion also is smaller. 3) glass/plastic lens has to be of minimum thickness for structural support, so that they don't shatter at the smallest impact.
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Too weak glasses do cause me pain from eye strain. Perhaps you’ve only experienced glasses that are only slightly weak.
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Why does holding my nose and eating bad food make it taste less bad?
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Your sense of smell plays a large role in what flavors you detect when you eat something. Your tongue can detect only a few basic molecule types, but your nose can detect thousands. Preventing airflow past your olfactory bulb (which provides your sense of smell) by holding your nose reduces tastes considerably. As an experiment you can try yourself, raw apples and raw onions actually taste similar if you hold your nose. If you want to be a chef, a poor sense of taste is a hindrance, but you could always focus on things like visual presentation and the mouth feel/texture of the food you cook.
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Taste is what your tongue does. That's salty, sweet, bitter, sour and savoury. Scent is what your nose picks up. A smell in other words. That might be 'strawberry', 'banana', 'ribeye steak', 'celery', and so on. Flavour is the mixture of the two. That's why holding your nose dulls the flavour of many things, but you'll still be able to taste, be it salt, or sugar or etc. Onto the actual question; when you exhale, even if you think you're doing it through your mouth, particles will still move through your nose, which is enough to detect scents of the food, which will contribute hugely to the overall flavour.
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Since entangled particles react to each other instantaneously, would this make instantaneous data transfer possible via quantum computing?
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No. You prepare two particles in an entangled state. Particle A and B, now you take them to opposite sides of the room, the world or the universe. You measure the state of particle A, you now know the result of the measurement of the state of particle B. That's all. You have no method of transmitting information because you cannot choose the state of particle A, you can only measure it.
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When particles are entangled, they share a state until measured. A practical example of this is that if you measure the spin of one of an entangled pair, the other will then always be found to be spinning in the opposite direction. It's not the case that changes made to one propagate to the other, so you can't send information this way. Additionally, even the fact that the "knowledge" of a particle's spin (due to measuring the other in the pair) travels faster than light doesn't actually violate causality - you have no control over which spin you measure at your end of any hypothetical communication device. Put simply, you have a device capable of interacting with far-flung parts of the Universe instantly, but you have no control over what message you send with it.
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What causes pain and why do opiates change the perception of it?
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In your brain you have a number of pain centres. These cause pain when stimulated. You have lots of nerves in your body that can activate them when you are cut or burnt or damaged. On other brain cells or on nearby cells that stimulate them are opioid receptors. There are a variety of types but _URL_0_ Is the main one. When activated it causes a reduction of pain. Your body has many reasons it might need to reduce pain, such to increase activity, to allow pregnancy. Endomorphins and other molecules bind to these receptors and cause reduced pain. Opiates also bind to these receptors and cause a reduction in pain.
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Dopamine is involved with the perception of pain, but not in a way relevant to this question. Endogenous opioids are responsible in this case. They are released under circumstances of acute stress. This is because evolution has taught us that when disaster strikes, your main concern shouldn't be your injury--it should be survival. As for why small injuries haven't got the same effect, the answer is the same: it's for survival purposes. Pain exists for a reason. It's beneficial to feel pain when injuries aren't life-threatening. Have you ever seen pictures of people born without pain receptors? They are covered in scars.
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Why has Hdr been so common in cameras for so long but is only now beginning to move into mainstream TVs, Smartphones and games consoles?
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They're different technologies. The HDR in cameras involves taking two shots at high/low exposure, then merging them to a single photo. The HDR in video displays refers to the ability to show a wide range of brightness.
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HDR stands for High Dynamic Range imaging. In laymen's terms, it takes several photos at different contrasts sort of at once, and then combines the images together. This way, the picture looks more like what your eyes see.
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How is ball lightning made? And how does it behave?
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We do not really know. It has been observed by scientists so rarely that they do not have much data on it. One of the primary theories on it is that it is caused by lightning strikes throwing charged particles of dirt into the air and they coalesce into ball lightning after a time, but they simply do not have to data to come up with more detailed theories.
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This is pretty commonly asked about lightning, maybe that would answer your question. _URL_0_
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If something becomes legal while you are being prosecuted for it being illegal will you still be found guilty.
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As far as I know, yes. You still committed a crime while that act was illegal. unfortunately.
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When doing something illegal and paying a fine is more profitable than doing something legal, it's just the cost of doing business. Businesses are rarely required to admit any wrongdoing, and there are no real repercussions.
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I was told once in science class that a small amount of mercury could be used to destroy an aeroplane. Is this true?
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I've never heard of mercury having these properties, however I know that Gallium will eat away at Aluminum, and has roughly the same properties (liquid at room temperature) as Mercury, but much less toxic. [Here's a video by NurdRage demonstrating Gallium's strange ability.](_URL_0_)
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Firstly, just because something has always been around, does not make it safe. Secondly, you need to differentiate Mercury the element from mercury-containing compounds. Having an atom of a certain element in a compound does not mean that that compound will have properties of the element. A trivial example is Sodium and Chlorine gas vs. Sodium Chloride. Sodium is very reactive and would cause burns if you ate some, and chlorine is a toxic gas, but when the atoms of these two elements are bound in a crystal structure, or their ions are dissolved in water, they are fairly harmless (table salt). Lastly, you must consider dosage. Almost anything (well just about anything I can think of, including water) is toxic when you have too much of it. So the question isn't if Mercury is bad for you, but *how much* Mercury is bad for you, and *how much* Mercury are you in contact with depending on your environment and diet choices.
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Does an earthquake impact the temperature of a place ?
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No, there is absolutely no scientific evidence of earthquakes affecting weather, or vice versa.
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Realistically no. Earthquakes are caused by tectonic shift, not weather. Granted it is possible that an earthquake that occurs during a long drought could cause more damage from fires, or that one after a heavy rain could cause more severe land and mudslides which would also be catastrophic. But the weather, as far as I'm aware, has no discernable effect on earthquakes.
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What's really happening when you are meditating?
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I forget which is which, (alpha/beta) waves but meditation is the act of controlling which waveform your brain operates. Different wave forms are generated by each state of mind, rem sleep, wakefulness, etc. You seeing a light is more often than not a visualization fabricated by your brain in the absence of any external visual stimuli.
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Meditation has been shown to alter brain structure in brain regions associated with memory, stress, empathy and concentration _URL_2_ Furthermore, if you would like to hear someone discuss meditation from a secular standpoint, watch this video of Sam Harris, it's awesome _URL_2_
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Are there any gaseous planets with a similar atmospheric composition as Earth?
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There might be, but they're probably not very common at all, for two major reasons: 1.) Earth's atmospheric composition is *heavily* influenced by photosynthesizing organisms, which might have a much harder time evolving on a gas giant. 2.) A planet (or rather, protoplanet) massive enough to hold onto a deep atmosphere would have a much different atmosphere from Earth almost by default, as it would have gravity sufficient for retaining hydrogen and helium, even if it were much warmer than the gas giants in our Solar System.
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Technically, there's nothing preventing a large quantity of gasses other than hydrogen and helium from forming a gas planet. Realistically, gas planets are formed from the same gas clouds and disks that form stars; even if seeded with heavier elements, those heavier elements are going to be mere fractions of the masses of hydrogen and helium available. So such a planet seems fairly unlikely.
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What is "blight" and why have American Chestnut Trees been so badly affected by it? Where did it come from?
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Briefly, the fungus was likely accidentally imported from Japan in the late 19th century. It was first identified in New York City in 1904. Generally speaking the American chestnut had very little resistance. The blight was aided in largely eliminating the trees from the forests by poorly coordinated responses to the blight including massive harvest operations that likely removed trees that would have shown greater resistance, though those would have likely been rare enough their main usefulness would have been in making the backcrossing easier. I highly recommend [American Chestnut: Life Death and Rebirth of a perfect tree]( _URL_0_) It is a few years old now, but it is a fantastic history of what happened to the chestnut as well as how important and special the tree was.
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Your individual experience doesn't necessarily represent the norm. It is actually pretty common for the stump of a tree to continue living. The American Chestnut, in particular is a hair's breath from extinction by the grace of this very mechanism. Early last century, a fungal disease called Chestnut blight was introduced into the tree's native range in the Appalachias via New York. In the ensuing decades, the specie was virtually wiped out as the above ground portions of affected trees die after the infection encircle the trunk. The still living roots of some trees however still continue to send up shoots. They grow for a short while before ultimately succumbing to the fungus again. So although "functionally extinct" as they are no longer able to effectively breed and propagate naturally, enough of the species still exist, maintaining a meaningful Gene pool that scientist hope to be able to revive with a number of [ongoing efforts](_URL_0_).
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What are the physics behind different baseball pitches?
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I'd recommend *The Physics of Baseball* for a detailed look at the game.
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They have little or no spin. Spin stabilizes the ball and makes it fly straighter. Also, the seams can catch the air unevenly, where with a spinning ball that all tends to balances out. The problem with the knuckleball is no one really knows where the ball is going to go, not even the pitcher.
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What are the physics behind different baseball pitches?
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The spin in which the pitcher imparts on the ball as they release it. So the way they hold their fingers causes the ball to rotate. The friction of the air on the ball spinning causes draft and thus ball moves oppositely
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They have little or no spin. Spin stabilizes the ball and makes it fly straighter. Also, the seams can catch the air unevenly, where with a spinning ball that all tends to balances out. The problem with the knuckleball is no one really knows where the ball is going to go, not even the pitcher.
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Why does Netflix have some of their better movies only on DVD? Wouldn't it be cheaper to have it online?
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That would be because Netflix doesn't have the rights to stream the movie. The rights to distribute a DVD are different from the rights to stream a movie. These rights costs money so Netflix can only afford to have a certain amount available for streaming. Furthermore Netflix might not be able to acquire the streaming rights for a movie even if they're willing to pay if the rights have been sold to another streaming service.
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Because the DVD was a considerable improvement. Higher clarity, no need to rewind, and smaller, more reliable form factor are all huge bonuses. Blu-Rays, though, what's the difference? Yet higher resolution and greater storage capacity. VHS needed upgrading because it could be so blurry/damaged at times that it was literally unintelligible. But anything digital and over 720 resolution is basically just a luxury. And a DVD is enough to store a whole movie, so the extra capacity of Blu Rays really amounts to little. EDIT: Same thing with 4k movie discs. Replacing your existing movie collection, provided you have a 4k tv and player, is just not worth the cost to some because it's so incremental.
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Were ancient Greek statues really coloured like this?
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There was a good discussion about the specifics of the color recreations on the sub a few weeks back; you can read it [here](_URL_0_).
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The Spartans infamously ate *melas zomos* (black broth), which other Greeks considered disgusting (Plut. Vit. Lyc. 12.6, Ath. 4.138d) and which contained blood as a major ingredient which gave it its colour (Suda Z, 136).
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Why do dogs kick their back leg when you scratch their stomachs?
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[Searched](_URL_1_) Top comment provided by [its_ametaphor](_URL_0_) > It is because you are scratching near a shallow (as in, closer to the skin) nerve area called a saddle region (usually your dog's back and sides of his legs and tummy) and his nerves think it's an itch and there is an involuntary twitch response for him to scratch it.
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It's similar to a knee-jerk reaction, called the Scratch Reaction. It's involuntary, but not uncomfortable. My dogs both seem to enjoy it, but maybe that's just because they're getting a good scratch! (Source: Sister is a vet, I asked her...)
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Why do boxers jump rope?
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It builds endurance, helps train footwork, and builds up the muscles in the toes and calves necessary for powerful punches.
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By getting hit is basically the idea. There's some other techniques to alleviate how much the hit hurts you as well, such as expelling your lungs (usually shouting) when you get punched in the stomach so the wind doesn't get knocked out of you. Also learning how to redirect hits into 'softer' sections of your body is helpful. Your body also adapts a bit; a lot of boxers have super messed up knuckles as your body learns to deposit more calcium into those locations, every time you break a bone your body will deposit extra calcium to that break and it's leave a 'scar' on the bone, you could imagine thousands of tiny little fractures could add up for those training. But yea, basically they get hit 'lightly' a million times every day so during a match their body is built for it. At the end of the day a hit to the head is still a hit to the head, there's not much you can do to train for that.
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Why has "It" become the most successful horror film in modern film history?
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because its a good movie Modern horror is basically cheap jumpscares and excessive gore. Its really easy to make people jump but none of that really fills peoples desire for "horror" because its such a fleeting feeling. Theres no dread, its just a sudden scare and thats it. Good horror movies know when to use jumpscares and when to build tension and dread (and also know that jumpscares can be even more effective when good atmosphere is built). This is significantly harder to do though, and takes some good acting and some writing chops. I can count the number of movies to do this well in the last 10 years on my fingers. It does this exceptionally well, along with having a really impressive child cast ( very hard to do), and is also a really amazing adaptation of a very famous book (even harder to do) while still having its own identity. Pretty simple to see why its so popular when it does everything right.
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Because most recently produced horror movies are poorly produced, overmarketed money grabs. They don't really have any artistic value, their plots are predictable (wow! The black guy died first again! Who'da thunk?), they don't spend much on special effects, and they don't have any of the philosophical value held by some older thrillers. They were made for one reason and one reason only: to entice people to come to the theater for a cheap thrill and an espensive ticket.
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Why do most companies prefer or are more likely to hire female candidates for clerical positions?
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I used to work on equality\-related employment data for a national government. There are lots of reasons, which vary by country. But one major reason is that women are more likely to apply for clerical positions because the role is slightly gendered, and advertisements for these roles reflect that in their language. This tendency is strengthened when we talk about unqualified workers, because women are more likely to apply for clerical work than \(for example\) manual labour positions. But like with any gender related issue, the real picture is very complex.
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Not to be a dick, but women weren’t a part of the workforce then. Now they are. So we’ve doubled our available workforce and halved our positions by sending manufacturing jobs overseas. It’s a buyers market for anyone doing the hiring today.
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Why is it that in the American Mid West, the sky turns a very intense shade of green before tornadoes spawn?
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“Thunderstorms, which can be the home of tornadoes, usually happen later in the day, when the sun is approaching the horizon. That creates a reddish tinge in the sky, as any fan of sunsets knows. But light under a 12-mile high thundercloud is primarily blue, due to scattering by water droplets within the cloud. When blue objects are illuminated with red light, they appear green.” -Scott Bachmeier
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I don’t have a real scientific answer for you, but I’ve seen the sky turn weird green and yellow colors before, but it’s always right before a really bad storm
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Why does violent/sexual trauma of children at a young age sometimes cause them to grow up and commit those same acts on other victims when they are older?
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We don't fully* understand the brain yet, so any answer has a lot of speculation and depends on the person. Based on what I read from an expert on this topic, I think it becomes a recursive/intrusive memory (very bad memories that keep coming to you despite the years) due to the trauma and in some cases the victim keeps replaying the memory untill it becomes a common occurrence for him and then they start to view children as "acceptable targets". Some people could start to fantasize about children as a defensive mechanism (To keep the bad thoughts away, they turn to pedophilia and they start to feel mental "relief"). I saw a thread on reddit where some(a) ex-pedophile(s) came forth saying what pedophiles need is support and confidentiality to overcome their problems, not publicity and death threats. Feel free to disagree or correct me, but this is an extremely sensitive subject.
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Various reasons but essentially it's survival of the fittest. If a parent knows that their young is weak, or won't likely survive, they'll reject it and often times kill it.
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How can we know that all type 1a supernova have the same luminosity?
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Because they all happen because a white dwarf has absorbed material from its companion star until it reaches a certain critical mass of around 1.38 solar masses (mass of the Sun) and goes supernova. Type 1a supernova are included in a group called standard candles which are used to form part of the [cosmic distance ladder](_URL_0_).
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1) We can see remnants of supernovae that have happened recently ([wikipedia link](_URL_0_)), but it's largely inference. 2) More massive stars form heavier elements and also live shorter lives. The most massive stars only live of order 10s-100s of millions of years, so many generations of them have been born and died since the Universe was formed. 3) Stars are far apart on human scales, but 14 billion years is a *long* time, and the matter in question is thrown out by supernovae at appreciable fractions of the speed of light, so it tends to get "mixed" pretty quickly on cosmological timescales.
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Has anyone ever attacked a country during a military parade?
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The closest thing like this to happen was when Anwar Sadat was assasinated by elements of his own, Egyptian army on October 6th, 1981. However, this was a domestic coup, not a foreign invasion. Nations that like to have these large military parades usually have an enormous military. Only a small portion of it is used for these parades. One exception to this would be Nazi Germany during the mid 1930s. Their large Nurenburg rallys actually did contain the bulk of the German military during the early stages of their rearmament. However, Britain, France and the USSR did not want to start a war with Germany, before September 1939. The Soviet Union did not even want to start a war with Nazi Germany in 1939.
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This question came up 8 months ago and [got some pretty good discussion](_URL_0_). The theory we came up with after discussion was that parades, except in wartime or the immediate postwar, have been supplanted by such things as air shows, Fleet Week and holiday parades that include military elements without being overtly martial.
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Is it safer to stream movies than to download them? Why or why not?
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streaming means you are not participating in redistributing copyrighted material. there is no law against watching streamed movies.
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Not what you asked but.... > I can't even do that even when I pay good money to legally access these movies. You paid good money to legally **stream** these movies. You were caught illegally **downloading** movies off the site. When you signed up your agreed to not download off the site. The poor internet connection isn't the fault of the popular movie streaming site. If you want to watch movies without streaming them then go to redbox kiosks or go to torrent sites to illegally download.
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Was there ever a point during the War of 1812 where the British could have tried to return the US to colonial status?
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Sure, they could have tried but would have resoundly failed. All major British invasions during the war of 1812 were defeated notably Lake Champlain, Baltimore and New Orleans. Britain couldn't even even gain control of the Great Lakes which was a perquisite for control of most of the Northern states. British successes were largely limited to stopping American invasions of Canada, seizing peripheral territories like Mobile and Northern Maine, raids in force in Washington and along the Chesapeake Region, and the blockade of the United States which wasn't complete until late 1814. You also have to recognize the tremendous growth of the geographic size of the United States since the end of the revolutionary war, made the chances of Britain returning the United States to colonial rule extremely unlikely from a purely logistical standpoint. It's hard to give a more in-depth answer since the plausibility of British returning the United States to colonial status is virtually zero.
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Are you sure that you're not asking for War of 1812 between American and Britain? France had been in a state of perpetual war with Britain since 1803.
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How did Crimean Greeks and Jews survive two thousand years of invasions and conquests with their cultures intact?
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To clarify, when asking about Jews, do you mean Crimean Jews, or Jews in general, and by Crimean Jews, are you referring to both Krymchaks and Karaites?
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The Ottoman spent centuries fighting the Persian Empire within the Caucasus. As a result each side forged alliances with the various rulers for varying amounts of time. To help forge these alliances, daughters/sisters would be sent to Constantinople as a means to keep favour with the Turks. Its also worth noting that unlike the other regions under Ottoman control, the Caucasus was never formally incorporated into the empire; though many regions were effectively vassals, they still nominally had independence, and thus could help explain in part why they had such a large number of consorts: it helped maintain their status.
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why do so many people oppose wind power?
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Four major issues: Noise: Those turbines are LOUD, I mean loud enough you do not want to be anywhere near them. And the sound is extremely irritating to boot. Space: While each turbine doesn't take much space on the ground for it's base, the entire field needs to be massive, and it makes doing anything else with the land below much more difficult or expensive because it is no longer a consistent, unobstructed field. Birds: The turbine kills birds of prey, like eagles. That upsets some people, and we have no clue how to stop that from happening. Inconsistency: Like solar power, wind power can only be found consistently in certain areas, and even then it can have lapses that make it much more challenging to use.
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Generically speaking wind is the motion of air moving from high pressure zones to low pressure zones. It can be caused by any number of things but a major player is ocean currents that move warm water (and air) around the globe. Other events that can trigger wind include but are not limited to: Solar Radiation, Earthquakes, Volcanic Activity and Meteorites.
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Why do we get a "someone's watching me" feeling when someone is watching us, despite not knowing for sure that we're being watched?
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We don't really. People get that feeling all the time when no one is actually watching, and they quickly forget it happened. Other times they definitely don't get it when someone is actually watching. But the few times you do get that feeling AND you catch someone looking at you, those moments stick in your memory. So you falsely think you are better at sensing people than you are.
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That feeling of being watched is all in your head and you probably only remember the times you were right and forget the times you weren't. You can't actually feel someone looking at you.
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Does the alcohol we ingest disinfect anything in our systems?
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> [A mixture of 70% ethanol or isopropanol diluted in water is effective against a wide spectrum of bacteria, though higher concentrations are often needed to disinfect wet surfaces](_URL_1_) + [most drinks have under 60% alcohol my volume](_URL_0_) = The alcohol we ingest is probably not a great disinfectant. The digestive system would certainly qualify as being a wet surface, so it would dilute the alcohol further. Additionally, it starts getting broken down as soon as it reaches the stomach by [alcohol dehydrogenase](_URL_2_) so it could only be "disinfecting" stuff in the oral cavity and esophagus.
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Bacteria are definitely capable of becoming less sensitive to alcohol disinfectants, and has been observed for a long time. Resistance has been seen to occur by changing the fatty acid composition of the membrane, and I'd imagine it's also possible by reducing surface permeability. An area of current interest in the production of alcohol biofuels is generating fermenting organisms that can tolerate higher levels of ethanol. It's also interesting to note that bacterial spores are typically very insensitive to killing by ethanol. Spores are incredibly tough to a wide range of things that would kill an active bacterium very quickly. The main way to kill C. difficile spores is bleach, because they're just so insensitive to everything else. _URL_2_ _URL_1_ _URL_0_
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what Wolfram Alpha is suppose to do?
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I think the goal of it is to be able to answer any knowledge or data question really quickly, but it's still in a very early state of development... it seems to only respond to keywords and not very complex questions, at least in my experience. I just wish it was more like the worldwide supercomputer 'Multivac' in Isaac Asimov's sci-fi short stories, which could answer any question you could throw at it (except one... I highly recommend anybody to read "The Last Question" it's only a ~15 minute and [completely mind-blowing read written in 1956](_URL_0_)), but I'm pretty sure that Wolfram Alpha, Google, and Reddit (yes just these 3) will all culminate into this within the century anyways (and I would think that Wolfram Alpha was inspired by the Multivac idea, though there were probably other similar predictions of such an entity before)
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It allows us to test and constrain theories in nuclear physics. They don't have any practical use, but they are very useful and important to people who study nuclear physics and nuclear chemistry.
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How does Adderall work exactly?
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I currently take adderall (prescription of course) and I was curious as well as to how it works. This article _URL_0_ (sorry I'm on my phone I forgot how to make the text a link) should shed a little bit of light on it, as far as actual performance goes. It's actually quite interesting. The drug doesn't actually affect any chemicals that affect memory, concentration, etc. What it does is trigger an increase in Dopamine. The feeling of euphoria can improve your mood, and you will feel motivated to do the things you need to do. This makes it seem like it's improving your concentration. The links at the bottom of the article help explain it a bit as well, hope this helped!
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Adderall increases dopamine production. For healthy people, it becomes too much, and the dopamine receptors become less sensitive. When they later quit, they get less dopamine than they should, which causes them to have less motivation and pleasure in general.
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Why haven't bears or tigers or other boss animals been domesticated?
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Domestication of an animal is something that occurs over generations of attempting to domesticate that animal. It's how we ended up with the modern cow, dog, chicken, etc. The most rapid domestication I can think of in history is the domestication of the fox by Russian scientists during the cold war. They selectively bred foxes for traits that seemed ideal for human interaction. In a few generations, they had foxes THAT ACTUALLY WANT TO SNUGGLE. LIKE THEY INSTINCTIVELY CUDDLE YOU. IT'S IN THEIR BLOOD. Without a reason to put the time, resources, and man power into it, no one will ever domesticate a bear. That, and many species of bear (and more of tiger) are endangered. You'd never be able to pull large sample sizes out of the wild to do selective breeding experiments on them.
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Jared Diamond in his book *Guns, Germs, and Steel*, aruges that animals have to satisfy 6 criteria to be candidates for domestication. You can read a straightforward summary of the criteria he identified [here](_URL_0_).
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Why are the words for "cat" (gato, katze, mačka) in European languages so similar, while the words for "dog" (hund, perro, pes) are so different?
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Cat is a very old word - it was used in Africa and the middle east 2000 years ago. Dog is a very new word - it replaced Hound in English - about 300 years ago. Ie. Cat has had time to have an influence on other languages, dog hasn't.
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*Why* is cognate to German *warum* and Dutch *waruum*. Like most common and old words in English, it's ultimately from German roots, not from Romance ones as French and Spanish are. Compare English *cow* and German *kuh* to Spanish *vaca* and French *vache* (both from Latin *vacca*), for example. When English words have Latin or Greek origins, they're usually either more recent or technical, frequently both.
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How do plastic cooking utensils not melt and how is it safe to use them with boiling heat (without chemical poisoning)?
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"Plastic" is pretty much used as a catch-all word for polymers. Plastic *is* a polymer, but not all polymers are plastic. Some polymers have an *extremely* high melting point. Teflon, for example, has a melting point of over 600°F (which is over 300°C). Some polymers have an even higher one than that!
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Plastics can be either thermoset or thermoplastic (in aid of simplicity). Thermoplastic types can be melted down, any number of times you want. Thermoset plastics are 'locked' into their final form: _URL_2_ _URL_2_
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Why do people in certain countries like America have so many last names, but people in countries like China only have a few set surnames?
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In the US in particular, you're likely to encounter surnames of many different origins, from English, Scottish and Irish, to German, French, and Chinese. In China, almost all of the surnames are of Chinese origin.
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Some of that is weirdness from transliteration. There are at least six surnames that are transliterated simply as Li, for instance. Other surnames are less extreme examples: Yu and Ji come to mind. Sometimes the different forms are respected (Lü vs Lu), sometimes they're not. The language barrier certainly explains the apparent scarcity of Chinese surnames. Adjust for that and Chinese surnames essentially follow the same distribution curve as other cultures.
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Are there any Books I can read about The Carthaginian civilization? (If it can be called that.)
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I noticed another user recommend *Carthage Must Be Destroyed*, and while it's not a bad book (I've read it), [one of our more brilliant flairs wrote a partial review on the book.](_URL_0_) Spoiler alert - it's mostly negative. Miles uses *extremely* flawed methodology in writing the book, cherry picking only things that support the points that he wishes to make. Personally, I would highly recommend a book called [*The Carthaginians*](_URL_1_), by Dexter Hoyos. It's a tad smaller and a tad more expensive, however it's...really REALLY good. Take that as you will :)
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Hello there! I highly recommend Dexter Hoyos' *The Carthaginians* (London and New York: Routledge, 2010), which provides a fairly up-to-date overview of the topic in about two hundred pages. I would avoid Richard Miles' *Carthage Must Be Destroyed* (New York: Viking, 2010); while his coverage of the period of the Punic Wars is *okay*, he makes a lot of careless mistakes and unsubstantiated claims early on in the book, especially when he discusses the Phoenician background. If you happen to be interested in the Phoenicians in general, you're best bet is Glenn Markoe's *Phoenicians* (Berkeley and Los Angeles: University of California Press, 2000); it's free to read online via the [UC Press website](_URL_1_) and [Google Books](_URL_0_)! :)
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What gives electrical fires their distinctive smell?
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do you mean the smell of ozone? I can't really describe it but it's really distinct and you would smell it after lightning storms, around arcing electricity, and some brushed electric motors.
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Water evaporates more readily off of warm materials, taking trace elements, aka the smell, with them.
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How can people be allergic to eggs but not chicken?
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Proteins are made out of building blocks called amino acids. When someone has a food allergy, their immune system overreacts in response to a certain nutrient. In the case of an egg allergy, it reacts to a protein in the yolk or white (or both). These proteins differ from those found in chicken meat. So someone can be allergic to a specific type of protein in the egg without being bothered by the different kinds of protein found in chicken meat. The chicken is able to produce the egg by rearranging amino acids into different kinds of protein molecules. Our own bodies also make different kinds of proteins. For example, hormones are often proteins.
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Immunotherapy is what my younger brothers went through to get over their allergies with eggs. _URL_1_
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Why does Beer taste good when it's cold but tastes awful when warm?
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Same reason CokaCola tastes good cold but too sweet warm, or how coffee tastes good hot but too bitter cold. When you drink a beverage et an extreme temperature (i.e. cold or hot), the temperature of the liquid changes how your taste buds react to it. The more extreme the temperature to either side of body temp, the less your taste buds will actually taste. So when you drink a super cold beer, your tongue is actually missing a lot of the bitter flavour that you get when you drink it warm. That's why certain craft beers are made to be served at "cellar temperature", which is slightly colder than room temperature - so that you can taste all of it.
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Cold temperatures cause molecules to move slower, which liquids to release fewer molecules into the air when cold. This decreases the scent of the liquid, and one's sense of taste is dominated by one's sense of smell.
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Why do baseball players put weights on their bats while on deck?
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Partially to loosen their shoulder and arm muscles. The extra weight helps to loosen them up. Also, if you swing something really heavy several times, it acclimates your muscles to a certain amount of strain. If you get them used to swinging a heavier weight, you can suddenly swing a lighter weight much faster and more easily than you would if you just warmed up with that lighter weight.
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Because they are wearing special gloves, the express purpose of which is to apprehend said baseball.
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what's the difference between 10 sets of 5 reps and 5 sets of 10 reps
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That's the thing though , you wouldn't do both of these training methods using the same weight.
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The 20-pack is the regular price and the 10-pack is inflated, they don't want to sell you a 10-pack for 2.50.
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Why do talk show guests who have shirt microphones change to a big hand mic when singing?
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Hand mics can pick up a greater range of pitch; singers pull mics away when singing louder so they don't distort. Plus they are used to performing live with a mic in hand.
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They are trying to avoid clipping. See, a microphone can only handle so much pressure. So imagine a singer normally singing at a volume of 5 (just putting it in numbers so it's easier to understand). The sound guy will then adjust the volume of the PA so that the singers voice at volume 5 comes across nice and crispy. A professional singer knows that it's hard for the sound tech to anticipate what he (the singer) will do. So instead of just singing louder or less loud and hoping the tech will adjust, he just moves the microphone further away when singing louder and closer when singing less loud than his usual volume. Also, as you asked about sound effects, if you sing away from the mic, a little (really just a little) more reverb is created as more ambient noise from the room is captured. But this effect is really small.
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What happens to a woman with a serious milk allergy if she starts lactating?
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The most common milk allergy is to the protein casein. This protein differs in animals. A person allergic to casein would likely be allergic to one *type* of milk. It's extremely rare to develop a case of breast-milk allergy. It's technically possible for the immune system to attack a protein in your own breast milk, if your body no longer recognizes that part of your body as yourself.
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It shouldn't. While not completely sterile, the milk is relatively protected from the outside environment. Milk quality can be affected by mastitis however, or infection of the mammary glands. At least in the US, all milk is evaluated for quality and somatic cell count, and contaminated milk is discarded. Also consider that milk is produced postpartum in response to hormones. If the cow stops being milked, after a time she will dry up and stop producing.
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How are boogers made?
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Boogers are made by particulate matter being trapped by the mucus membranes. Basically when you have a booger it is your body changing its natural air filters.
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Boogers are dried up mucus which is released by the lining of your nasal cavity. They accumulate when you cry because the tears drain through the inside corner of your eye (the puncta) through a 'drain' into your nose (nasolacrimal canal), thus more fluid in your nose which dries up and turns into more boogers.
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Bayes' Theorem in Probability
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To understand Baye's theorem, we must first understand the concepts of conditional probabilities and probabilities. A probability is the chance of an event happening, often denoted P(A), where A is the event, i.e. P(A)=1/6 where A is rolling 1 on a six-sided die. A conditional probability is the chance of an event occurring given that another event has occurred. This is denoted P(A|B), the probability of event A, given that event B has occurred. Baye's theorem gives us a method to relate probabilities and conditional probabilities. This can be combined with other theorems (such as the law of total probability, which provides a method to generate probabilities from conditional probabilities), to allow for a more complete analysis.
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> For example, in this situation, how can a test claim to be 99% accurate when it is wrong 67% of the time. It's not wrong 67% of the time. It's wrong for *67% of people who get positive results.* It's right slightly more than 99% of the times it gives a negative result. The point of Bayes' theorem here is, *there are so many more people who don't have the disease that even with a very accurate test, false positives will outnumber true positives,* and that this issue can be quantified and managed.
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