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c7iz07 | why is the air coming in cold when you open a moving car window, despite it being warm outside? | Imagine that you're covered head to toe in hair and the air that's flowing past you is really strong sticky tape. The more tape flows past you, the more body hair it's ripping off you.
The air removes heat from you as it flows past you, cooling you down and making it feel cold. | c02143ba-e310-48e4-8017-dcb979f67462 |
c7j4hy | why does glass create more condensation than plastic? | When water vapor in the air comes into contact with a material that conducts heat (like glass) then the water will lose heat through conduction (the heat moves into the glass). When it loses enough heat the water molecules will start to coalesce and stick together (the condensation). Plastic doesn't conduct heat as well so you don't get as much condensation. | e5624abd-88a4-4537-a01e-4dff8b93b7fc |
c7j5ce | How does a general anaesthetic work (surgery)? Why don’t we feel pain while under? And why doesn’t the pain wake us up? | To clarify, general anesthesia is a state. It can be induced with gases or injected medications. So at the absolute base level, we do not 100% know. What we mostly think happens is that the anesthetic gases work by activating a chemical called GABA in the brain that is inhibitory. Bascially, that chemical is the "off" setting for the light switch. The injected drugs we use that are anesthetics work the same way mostly. Ketamine works slightly differently, but disconnects the brain from the processing cores of the brain stem. | 871da02c-2bf2-441c-8a86-0b1ac5ccf07d |
c7j8oo | Would an extreme exposure of pollen cause someone to become allergic? | the short answer is: maybe. But no one really knows precisely why some people become allergic and some don't.
The past decade has seen a lot of advance in some of the qualitative understanding of allergy development. and it's not really dose-dependent (as you are basically suggesting in your question) but more temporal.
Two big risk factors for developing allergy seem to be: 1) not being exposed to the allergen consistently; and 2) not being exposed to the allergen while very young.
One of the big serological markers of allergy are a particular type of antibody against specific proteins. For example, birch pollen (the most common "pollen" allergy) has specific proteins which are associated with pollen allergy. These are named with a three letter code, followed by a letter, followed by a number in the order they were discovered. For example, the first big birch allergen was "Bet v 1".
Your immune system detects Bet v 1 and may raise antibodies against it. One type of antibody class, called IgE, may overexpress. People with high IgE levels specific for Bet v 1 tend to be allergic to birch pollen. Basically everyone has *some* detectable anti-Bet v 1 IgE. It's a matter of how much you produce. People exposed young and consistently, as I said, are less likely to get high levels of it.
There's also regulatory antibodies. You can make IgG4 antibodies, for example, against Bet v 1, and these are associated with an anti-allergic response. People living around birch pollen from a young age may have higher IgG4 antibodies against birch allergens and are less likely to be allergic.
then of course there's people who just randomly become allergic to something as adults (through a sudden IgE response). The mechanism for this loss of regulatory control is not well understood. Infections, some medications, stress, etc. do seem to be compounding risk factors, though. | f972e4bb-f665-45db-84e6-6629de1d2d5a |
c7jcg6 | How are humans waterproof, yet we can still sweat water? | Imagine this: You have a mouthful of water, but your mouth is closed, and you go swimming in the pool. The water from the pool doesn't flow into your mouth, but if you squeeze your cheeks, the water comes out of your mouth. Your mouth is likened to the pores that sweat comes out of.
For a slightly more complex explanation: The water inside of your body is always at surrounding pressure, or higher pressure. This means that water from the outside never wants to flow in. However, when the water inside of you is at a higher pressure, it can flows out. As for why the pressure inside of you is always equal or higher to the pressure around you, it is because pressure is determined by how much force is squishing a fluid. Since the pressure around your body is squishing your body, the water in your body is under at least that much pressure. Your body can squeeze it to further raise the pressure, but your body cannot stretch it to lower the pressure. | 19ca99aa-07ef-4a49-920e-6496d7603ec8 |
c7k9p6 | How are secret recipes still a thing with modern chemical analysis? | A recipe isnt just a list of ingredients.
Or even, the quantity of those ingredients.
It's preparation, cooking time and temp, tools used etc.
Anyone with the right equipment can tell you what's in coke. They can't tell you how it's made though. And that's the kicker. | 1cad7293-dc57-477c-84fd-34dc32961e76 |
c7ksht | How come you sometimes see red-eye in cameras with flash on, but you cannot see red-eye when you look into a mirror with lights on, even shining directly into the eye? | Angle. When you get redeye in a photograph generally the person is looking directly at the flash and their pupil is dilated because it’s dark (hence the flash). When you’re in a lit room your pupil is smaller and you’re looking at the reflection of your eye, not directly at the light source. (Or you’re looking at the light source but then can’t see your eye) but mostly it’s the pupil dilation and angle. | a09d1b2c-56d3-44d4-a1c3-04db68ed4cf5 |
c7l0p3 | How do birds grow feathers? | Feathers are modified scales. If you look at a bird's foot there are scales and it transitions up to feathers along their leg. Fully mature feathers are similar to human hair--they are dead at functional state. They start off as 'pin feathers' little spikes hooked to the circulatory system. They are encased in a sheath of keratin, as the feather matures they elongate and the sheath flakes off revealing the fully formed feather, segment by segment. At least with parrots, there is a yearly molt. They drop a lot of feathers really quickly and are covered in pin feathers as they are replaced. | 14b13c6e-86ea-4ae1-b969-a12e099020bd |
c7l21d | How does blood cell production work? Do the cells that have nuclei (like white blood cells) undergo mitosis? | Blood cells (red, white, platelets) are produced in the bone marrow, without exception.
White blood cells possess nuclei because they do a lot of things that red blood cells don't:
* They produce antibodies
* They produce surface receptors to identify pathogens
* the production of the above requires active genetic expression and transcription
* The process of engulfing pathogens is energy intensive and requires intracellular signaling
* Energy production also requires signaling in its own right
There are other reasons that a white blood cell needs a nucleus, but those are the highlights. | 6ee8c1b1-ac5d-476e-b8b6-66968398aea3 |
c7l5sm | How does bluetooth work? | It's very high frequency (2.4 gHz) radio waves that allow two devices to not only connect to each other but also to share data between one another. It's similar to other such protocols, like wi-fi - the router and your laptop communicate and share radio waves to transmit and receive data. | 1e957486-3cff-4901-8645-83a7df8b2a72 |
c7l5sr | De-icing planes | SOURCE: am airline pilot
It’s two different systems for different things. De-Ice Spray on the ground, and Anti-Ice equipment for in flight.
The spray does nothing to prevent ice build-up during flight. The spray comes in two types: the first is just hot water (or hot water with alcohol mixed in to lower it’s freeze point so it doesn’t just refreeze as new ice). To remove any accumulated ice on the parts of the aircraft that produce lift. This is because the ice changes the shape of the airfoil and makes your wings less efficient, so with Ice build-up... you might not make it off the ground before the end of the runway.
Then there is the second type. Sometimes, if there is just ice buildup on the plane, but it is not actively snowing or raining... a pilot just takes the first type and off you go! But if there is active precipitation falling, we get sprayed a second time with this next material. This second spraying is a thick, gloopy, slippery slime that sticks to the aircraft. Depending on the manufacturer, it is rated for different absorption rates... and it is designed to absorb rain/snow as it falls and keep it from freezing and adhering to the plane. The , as you start to go fast and roll down the runway, it will slough off. Different manufacturers products have different time limits they can be in different levels of precipitation before they are considered fully-soaked and time out, and your plane has to be re-sprayed to reset the timer.
Basically, the whole De-Ice system is just to keep ice from building up on the aircraft while it’s on the ground. None of this spray does anything while flying, and it’s designed to all fall off the plane very shortly after take-off anyway.
Then, when airborne... we have Anti-Ice systems. These are usually electrically heated or pneumatically heated (with hot air from the jet engine) metal surfaces on the leading edges of the wings, control surfaces, sensor probes, and windscreen. They operate by just getting hot and melting the ice a little so the wind can knock it off. Not all aircraft have Anti-Ice systems, as they are very expensive. Most commercial aviation aircraft around the world do, but most smaller general aviation and private planes do not. | b4c04838-5e3b-4575-905c-64105b5a01a5 |
c7lb9q | why do finger and toe nails turn white as it gets longer? | The white part is dry nails because it's not touching the skin and getting the natural oils. This is also why the white part turns translucent when you submerge them in water for long enough but go back to being white when they dry. I googled this a while back cause I was curious too hahaha | 104d4dcd-3b41-453c-83df-4c57d3156d4b |
c7lm6z | How are we able to hear multiple frequencies at once? | [This figure should help explain it.](_URL_0_)
A shows 4 waves each with different frequencies and C shows what you get when you combine those waves together. (Ignore B and D). A combination of different sound waves creates a single wave with a unique pattern. So instead of a speaker moving in and out by same amount (wave amplitude) at a steady rate (wave frequency) it does a mixture of varying amplitude and frequency to create one sound wave that sounds like what you get when you combine lots of different sounds.
Imagine you ear as the reverse of the speaker. Just like a single speaker can make the combined wave (like shown in C), when a combination of sounds hits your eardrum it will move in and out in a complicated pattern that matches the single wave you get when you add those sounds together. Your eardrum is just a speaker in reverse.
Edit: Forgot to mention ears. | 78d16980-431e-491a-869b-de2eb614bf0b |
c7lmow | Why do nuclear reactors rely on diesel generators in emergencies? | > Why do nuclear reactors rely on diesel generators in emergencies?
They work.
In an emergency situation where failure can lead to an entire city becoming uninhabitable for centuries, that's the only thing that matters. Batteries are fragile and even petrol engines have more breakable parts than diesels (spark plugs, specifically).
Add in the fact that diesel generators are cheap, can be easily kept running indefinitely by trucking in fuel, and take up far less space to store a given amount of energy than an equivalent capacity of batteries and they're simply the best choice. | 8fb35684-76c9-45a7-b9f9-7ab7170daeaf |
c7lprz | Why does your stomach hurt when you receive bad news? | Bad news activates the amygdala which is responsible for the fight or flight reflex. As such, it dumps some of the same chemicals (adrenaline, dopamine, serotonin) in large quantities into your bloodstream, which have physical effects. | e7d54aff-0fe4-4fff-9159-992dda6186df |
c7lr9i | How does natural gas get made into synthetic oil and why is it better? | This topic is a bit complicated for 5 year-olds but I'll do my best:
Oil is a mixture of molecules called hydrocarbons. To make these molecules synthetically you need to start with 2 things at a minimum: carbon and hydrogen. Natural gas (mostly methane, CH4) has both, and it's combined with water (to provide additional hydrogen) in a reaction called Steam Reforming:
CH4 + H2O < - > 3 H2 + CO
After reacting natural gas and water you get a mixture of hydrogen gas and CO. This is called *synthesis gas* or '*syngas*', because it can be used to build many different organic molecules, such as the hydrocarbons found in oil. Here's an example of a reaction that uses syngas to make butane (C4H10):
10 H2 + 4 CO < - > C4H10 + 4 H2O
Voila, you've made a synthetic fuel starting from only natural gas and water!
You might assume that making a hydrocarbon absorbs heat, because burning a hydrocarbon releases heat. In fact making hydrocarbons from syngas actually releases heat as well, because the reaction produces water as a byproduct, which is a very stable molecule that releases a lot of heat when formed, so overall the reaction is exothermic. However the reaction has very low conversion unless performed under extremely high pressures.
The specific process that makes 'synthetic oil' is called **Fischer-Tropsch synthesis**, and it was developed in Germany almost a century ago, so it's far from new technology. Nazi Germany relied on this process to produce oil when they couldn't buy oil on the international markets due to trade embargoes.
'Better' could mean a lot of things, but the biggest benefit is that synthetic oil won't contain any impurities like sulphur, which is a major source of air pollution. | fe3225d9-063a-4d47-9c7b-bab7c2a7892e |
c7m4te | Why does air feel colder when blown? | When it's colder than our skin temperature outside, our body loses heat by transferring energy to the air molecules that collide with our skin | 158b1274-7911-4857-a820-6161c454d46b |
c7m6m4 | Why can't we incinerate all trash in lava? | Because it produces many different kinds of gases, both toxic and non toxic (greenhouse gases) that are horrible for the environment and humans. Doesn’t matter if it’s lava or just normal fire | e5cf1298-4c45-4a54-b4d8-2e7d2d63aba2 |
c7mo22 | What does owning masters to your music mean and why is it that the singer doesn’t always own their own music? | Owning the masters simply means you own a copy of and the rights to the original recordings of a particular piece of music.
& #x200B;
Singers actually rarely own the masters to their music, unless they are self funded independents. It's usually going to be the record label that pays for the recording the happen that will own the masters with the artist being on a contract to receive a portion of any sales, royalties, etc. Records are expensive to make and often the only way a record company is willing to fund a recording is if they own the rights to the music once it's done.
& #x200B;
Transfer of ownership of masters is the same as selling anything else - it's no different to selling something like a car. If somebody wants them they'll offer money and if the person/company that owns them wants to sell them for that amount they will. | cab1d598-e727-49a3-85e2-d6b01ff003c4 |
c7mopb | why does crying cause headaches? | When you're sad, your body releases stress hormones which set off neurotransmitters that trigger physical reactions. So you cry, which causes congestion in your sinuses, muscles in your head/neck tighten up and you wind up with a tension headache. It's just a mixture of that tension and possibly sinus pressure. Your body is in a stressed state, so it responds. | 0faa53c0-9b62-47e4-9464-22496fe48b6b |
c7mub7 | Why do some compounds have a higher/lower reduction potential than other compounds? | It depends on where an electron prefers to be. Electrons occupy orbitals (certain regions surrounding the nucleus), and the potential energy of an electron depends on the orbital it occupies and on the other electrons. Generally speaking, the higher the effective charge of the nucleus (meaning the charge that an electron actually "feels", some of it is shielded by other electrons), and the less repulsion between the electrons, the lower an electron is in energy. But the redox potential also depends on the electron configuration, if you add an electron and you have to spin-pair it, it requires energy. Carbon has a smaller nuclear charge than nitrogen, but it has a higher redox potential, because adding an electron to C is easier than adding an electron to N because then you have to spin-pair it. | f333b7e8-1688-4900-be5c-08692a414a95 |
c7n3th | How does a galaxy move? | Galaxies move based on gravity of their components (stars, planets gases etc) . Most galaxies have a black hole at the center , it's mass and gravity also affects the motion.
Over large periods of time millions and billions of years galxies may colesce with other galaxies affecting each others movements | de2a0263-5659-4a98-82b2-c95015a958ad |
c7n7h3 | How does Chinese magic cloth work? | The cloth itself is multi-layered. Once water is applied to the topmost layer, it undergoes a transformation from an opaque fiber to becoming transparent. The layer underneath, is black. Eventually, the water evaporates and the top layer becomes opaque again.
& #x200B;
This means it does wear in time. Though I'm sure it lasts quite a bit. | 3268c30a-04be-4764-af08-86ab36fe3792 |
c7n8j2 | How does nuclear fusion and nuclear fission both release energy? | Why does splitting the atom and joining the atom both CREATE energy?
Because we aren't splitting the same type of atom. When we talk about fusion we are talking about atoms lighter than iron. When we talk about fission we are talking about atoms heavier than iron. Iron is special because its nucleus is the mose stable nucleus. Generally moving towards the stable iron nucleus tends to release energy, because that means either 1) two less stable nuclei have been fused into a more stable one or 2) a less stable nucleus has been split into two more stable ones.
Here's a [graph of nucleus binding energy](_URL_0_). The higher the atom is the more stable it is in that graph, so moving from less stable (lower) atoms towards more stable (higher) atoms releases energy.
For example, splitting uranium into barium and krypton releases energy, but fusioning barium and krpton takes energy. On the other hand if we fuse helium atoms into a carbon atom that releases energy, but if we were to fission carbon that would take energy. | a8aebffa-0bad-40db-bf46-a4c7b774d4a5 |
c7nhl1 | does unripe fruit have lower digestible caloric content than ripe fruit? | After a fruit has been picked the count doesn't change. However the bioavailability does, as enzymes work to ripen and convert complex structures to simple ones like starch to sugar. | 291b228b-3f41-4500-9f74-bbb9758fd006 |
c7nnsj | How come the sound of electricity buzzing stopped when I'm near it? | It sounds to me like your outlet is either worn out and not gripping the plug very well, or someone bumped it and didn't notice that it was only partially inserted. The fact that it stopped when you got close was probably just a coincidence. Things like this tend to be intermittent. It's also possible that it is so loose that you walking over there caused enough movement in the fridge (or its cord) that it re-positioned itself. Unless they're concrete, floors can have a good amount of flex in them.
& #x200B;
The buzzing sound was an arc due to the poor connection between the outlet and the prongs. In addition, appliances like fridges draw a lot of current, so you will more likely get an arc than with something like a table lamp.
& #x200B;
Either way, keep an eye on it and get an electrician to replace the outlet if it does it again. Arcs create a lot of heat, so it can cause a dangerous situation. Especially with that piece of paper down there -- perfect recipe for a fire.
& #x200B;
Edit: Also, mini fridges should really be on their own outlet. They should never ever be on a powerstrip (or an extension cord) and they really shouldn't share an outlet with a powerstrip. | f23d8dea-912d-4bfa-b6b6-5bdbddb9badf |
c7nq97 | Why airline prices fluctuate so much within a matter of a day? | Simple answer , Dynamic Demand Pricing systems are used by major airlines to update all fare prices in real+time based on a variety of factors that maximize the airlines bottom line. High seat costs for booking the day of or a day before have been common practice in the airlines even before these systems we used.
Gone are the days of static prices for a particular route or season. Because airlines have a wealth of data at their disposal they use sophisticated models (or have a 3rd party companies that specialize in this business) give them the best rates (sometimes down to the seat on a given Flight) that will maximize their bottom line.
Here's a simplified example. A common flight from EWR to LAS (Las Vegas) is run through the model that looks at what time of year (is this peak convention time in Vegas?) historical passenger utilization for this flight last year,last month, etc. How many seats sold how many left, how many days before the flight, if it's not selling fast enough fares get reduced to a break-even amount, and so on... This sets the seat rate,then every , passing minute or so the model updates based on any changes. .
These.systems are slowing being applied to all sorts of Pricing. | 1f4f6aec-db4b-4d78-8030-2d488c8eedbe |
c7nsg0 | how the space stations were built. | Old 1960's and 1970's space stations.were generally just one large capsule or a couple of capsules that were launched and docked together in orbit
The current ISS (international space stations) is a mutli module space station built.pver the last 20 years of space launches
It's a joint project between five participating space agencies: NASA (United States), Roscosmos (Russia), JAXA (Japan), ESA (Europe), and CSA (Canada). | 996974a4-bcaf-4a9d-8232-d2b9d39025aa |
c7ntpc | Why does it seem as though information is retained more easily when writing notes by hand rather than typing them? | When you handwrite anything you tend to think more about what you are writing. Since writing is slower, you have to summarize what you need to write rather than having the ability to write it verbatim. This creates a stronger link to the material in the brain since you have have to think about the summarization. On the other hand, you have the ability to type much faster so we have the ability to type what we hear verbatim. This hurts our ability to remember the material because we are not actually thinking about it but rather transcribing.
EDIT:
There is also a physical aspect to writing. You feel the texture of the paper, the pressure of the pen or pencil, the speed of your writing, even the placement on the paper you wrote something. All of this helps you remember what you wrote at that time. Typing on the other hand will only give you a single (the same) feedback - smooth keys. Not very memorable. | 821411c5-a4b3-4256-a9a8-6b3c5277287d |
c7nwpc | How can suicide be illegal? | A law is passed that makes suicide illegal. It's not difficult.
If you're asking how they can punish a person once they're dead, there can still be repercussions on the estate (the stuff they own that they leave behind) or their family.
But the biggest effect is: if something is illegal, then assisting a person to commit that act is also illegal. You can see in [this wikipedia article](_URL_0_) that quite a few countries have changed their laws to make suicide legal (there are no repercussions to the family), but assisting someone to commit suicide is still illegal. | 6f245b33-7673-4104-8f77-08039054c84a |
c7o0id | How can TVs playback content with a framerate thats not dividable by the refresh rate? | The most common is playing 24 fps movies on 30 fps TVs. It converts 24 frames per second into 29.97 frames per second. Roughly speaking, converting every 4 frames into 5 frames plus a slight slow down in speed.
The first 2 output frames are original. Output frames 3 and 4 are a mix of input frames 1, 2 and 3. Output frame 5 is input frame 4.
_URL_0_ | ad6c1a34-0717-439f-945c-5de8cc88385c |
c7o6gx | Does the breakdown of carbon life forms add mass to the earth? | No, or yes. It depends on how you define the Earth.
If you are talking about everything from the atmosphere down, then no mass is added since the mass from the lifeforms is already accounted for.
If you mean just the soil and whatnot below our feet, then yes the bodies decompose and make their way into the Earth. The elements from those bodies are also used by plants and fungi and animals for growth, so it is taken out of the Earth too. The net difference between the bodies going in and being used is effectively nil, so the Earth's mass stays the same from that.
The Earth does gain mass over time though. This is done through small meteoroids that enter the atmosphere and usually burn up before they hit land. It also loses mass because lighter gases such a as hydrogen and helium leak out of the atmosphere into space. I'm not sure which is greater though to decide if it's a net gain or loss. | 50193f70-b2e9-4b5b-be55-eb554019f109 |
c7o6oc | why does exposure to water dry out the skin, especially in winter? | Your body produces natural oils which keeps moisture locked into your skin. Long exposure to water removes your natural oils, causing moisture to leak out.
So while at first water can feel moisturizing, after some time your natural oils are removed and your skin dries.
As for winter, in the winter it’s normally colder which causes the water in your skin to dry up or evaporate quicker making your skin dryer and tighter. | b5a20b59-d8f3-4c95-ba0c-1a84fde98495 |
c7odlu | once somebody takes the cap off of a honeycomb, how to they extract the honey? | They put the whole comb in a special kind of centrifuge and use centrifugal force to extract it. | e3882ea2-9397-474b-a453-6a3612577768 |
c7oll4 | Why are the colours used in the country flags so limited? | Most country flags are old enough that they needed easily and cheaply made dyes to be used, which are generally the primary and secondary colors. | 698f6149-325b-4b69-b2b5-f18d1418feca |
c7oswx | whats the problem with deepnude? | The ability to smear someones reputation with faked nudepics?
Especially as long not everyone knows this technology exists. | 0a373abf-cceb-406a-92c1-f68ff5db32d7 |
c7p9p9 | What is "PCIe 4.0" and what advantages does it have over its predecessor? | PCIe (Peripheral Component Interconnect express) is a standard for a type of socket in computers, generally on the motherboard, that other components like graphics cards, hard drives, wifi cards, etc, use to connect.
PCIe 4.0 has a transfer rate of 16GT/s (Giga transfers per second), which is double that of PCIe 3.0 and has lower power requirements.
PCIe 5.0 went up to 32GT/s for a total of 63GB/s with a 16 lane configuration, and PCIe 6.0 went up to 64GT/s, for 128GB/s with 16 lanes.
PCIe 3.0 was released in 2011. PCIe 4.0 was released in 2016. PCIe 5.0 will be released sometime this year, and PCIe 6.0 in 2021. | 7a902eb4-cbc0-4164-9bec-7c93fa3458f9 |
c7pmg7 | What is Fit & Gap? | Fit/Gap Analysis is used specifically in businesses. Simply put it identifies key data within the business and gaps that need solution.
This type of analysis is used on each functional section of the business to evaluate the business process or achieve a goal.
There’s much more complexity to it, but that’s the overall gist of it. | cf3565e6-0f79-4a16-ba51-01f45b6c4c83 |
c7pvwu | What is the conflict in Kashmir about and is there a way to solve it? | The conflict is simple: both India and Pakistan think Kashmir should be part of their country.
When the British Raj was split, the exact border location was up to dispute.
There could be many ways to solve this, but propably hardly any that makes both countries happy and not feel like they lost something.
Edit: some historical background for those who care. When the brits left they decided that states with muslim majority would be Pakistan and states with more hindus would be part of the Indian Union. Kashmir was a special case because it still had a sovereign ruler and he decided to stay independend of both countries. Kashmir had a muslim majority, but the elite there was mostly Hindu. | 9290dfdc-d864-411c-af13-b37f47281b79 |
c7q33n | What happens to our eyeballs when we close our eyes? Do they roll back or stay in the same position as they would when our eyes are open? | I understand (by the question) that you are an alien. Every person would know the answers
Busted! | 2fdbd6da-eb0f-4ea6-baf4-b9c14d9ac99f |
c7q5q7 | What happens when a limb is asleep for too long? | It is due to compression or irritation of nerves, paresthesia.
If your arm wasnt getting blood or oxygen while you slept, that tissue would die instead of tingle. | 6c8a7814-71e0-4986-b9c1-faf2973cfddd |
c7qc86 | how does someone run faster than someone else? | Running speed depends of 2 things: the length of your steps and the time between 2 steps.
To run fast you need to take long steps and chain them quickly.
To achieve this the muscles in your legs must be powerful (strong over a short time) as sprinters or tennismans muscles, but not necessarily very strong as weightlifters muscles. | 80f34774-ef35-4d17-b390-e39a873bb81c |
c7qetn | What does Cake Day do? | It doesn't "do" anything. It's like asking what does your birthday do? It is just the day you were born. Cake day is just a fun way of saying birthday, since you typically get cake on your birthday. For reddit it means the date you made your reddit account, so see it as your accounts "birthday". | 0f308698-3f59-4563-be54-0cfafe189678 |
c7qfxy | What is a boltzmann brain? | It is an example of the general idea that if you wait long enough anything that is even the slightest bit possible will eventually happen.
The general concept is not very different from the idea of the perhaps better know thought experiment of having infinite monkeys randomly bang on typewriters and having one of them by pure chance end up with the script to Shakespeare's Hamlet.
If you have some random arrangement of stuff like a deck of cards that you continuously shuffle, the longer you keep at it the more likely it becomes that the cards per pure random chance will end up in the correct order.
Usually we don't worry about stuff like that too much.
The bit about shuffling a deck of cards will only result make it likely in timespans that compare with the expected lifetime of the universe.
A human brain complete with memories and everything has a lot more variables than a deck of cards, but if you get right down to it, if you arranged every atom exactly as the atoms in your brain are arranged now it would be an exact copy of you.
In the vacuum of space there is some constant low level random fluctuation going on of particles being created and destroyed. In the general view of things this equals out to more or less nothing.
However there is a non-zero chance that randomly enough stuff might come into existence to actually matter on a big scale.
It is sort of like the idea that a glass of water might randomly heat up by spitting out an ice-cube. In theory possible but you would never actually expect it to happen.
When you wait long enough stuff that is merely extremely unlikely becomes inevitable given enough time.
When taking the really long view. Eventually stuff that seems impossible will happen.
The Boltzmann brain is an example of an absurd thing that could happen given enough time.
Matter randomly assembling by pure chance into something that works like a human brain complete with memories and everything.
A consciousness coming into existence full formed out of nothing at all.
In a universe that goes on forever it seems like an inevitable result that such impossible things might happen eventually, which seems pretty stupid.
Even worse is the idea that if Boltzmann brains are not only valid things that might occur at some point in time but actually inevitable things given enough time, how can you tell that you personally are a human being with a past that came into existence through evolution acting on arrangements of clumped together stardust and not just some random arrangement of matter which spontaneously came into existence a moment ago complete with memories of having been a human being for years.
You can't really know if you are a person or just a brain floating in space with false memories of being a person. Both are possible.
What might give you an existential crisis is the question of which is more likely.
When talking about forever some really frighting stuff may result. | 91d5025c-5708-4bdc-93dd-428eac32fdd8 |
c7quix | why super rich/popular musicians still work for record labels? | They help her do a lot of stuff at big scale.
She has enough money to start her own label sure. But the people working for big labels are very experienced in marketing, touring, press, album releases, distribution, international distribution, accounting etc.
These are all things Taylor Swift needs to be a mainstream artist. It would be very hard for her to do her own thing and find people that can work together like a well oiled machine immediately. She could build up her label over time, but that work take time, management, money etc. I'm sure she would rather focus her efforts on being a performer than running a label. | ac89070a-bac0-44b6-b9d4-e54a0564e3c1 |
c7qwqg | What makes some engines signifcantly more powerful than others although they run with the same type of fuel | Efficiency.
If you burn more fuel per cycle, that can up power output. But, if you make each ‘burn’ more efficient - extracting more useful energy - you increase power that way too. Typically, increasing engine compression ratio will do this; although it comes with problems which must be controlled.
The more heat energy you can direct towards driving pistons, instead of being lost to the cooling system or out of the exhaust, the more efficient your engine will be for a given amount of fuel.
Petrol engines are typically 25% thermally efficient, diesels are 40%. This isn’t just down to differing fuels, the compression ratios are very different too. | cdaaf962-127b-48a1-95c4-4643769acd9a |
c7qxa2 | Why do pubic hairs get curly as it grows longer? | To put it very simply, hair grows of 2 kinds of pores. Circular and oval. When hair grow out of circular pores, they come out straight. When hair grows out of oval pores, it gets curly (cos it's less directed, imagine it). | ee64f340-0693-4410-b0bc-b4132cb3c8fa |
c7r4bp | Why is it better to sleep in one big chunk, rather than taking a couple of naps throughout the day? | You can adapt your body to take multiple naps throughout the day, it has more to do with how society functions. A lot of the alternative sleep cycles call for a nap every other hour or so, and you can't really do that if you are working an 8 hour shift. If you have not obligations and work from home then you could do those cycles. However they are more demanding in that you can't miss a single nap without fucking your shit up, with the big chunk even if you pull an all nighter you can recover in about two days. | 88a36a10-e743-4125-8f23-b78391845c6b |
c7rc3q | How is the ozone layer healing? | Ozone is created through a reaction with normal oxygen (02) and solar radiation. It is then depleted through various chemical reactions. So the ozone layer isn't something that is static - it is constantly forming new ozone to replace the ozone that gets lost.
& #x200B;
We threw this natural system out of whack for a long time by pumping a bunch of chemicals like CFC's into the atmosphere that are highly reactive with ozone. This caused the ozone layer to lose ozone faster than it was able to replace it - hence the hole. We've stopped pumping a fair amount of these chemicals into the atmosphere so the amount of ozone being depleted by them has also decreased significantly.
& #x200B;
But there's still less than there should be, which is why the ozone layer is healing. What is happening is that because there isn't as much ozone as there should be more solar radiation is able to get through. One of the things this results in is more ozone being produced. As more ozone gets produces it will allow less solar radiation through so the rate at which it is able to be produced will slow down. Eventually it will get back to the point where it's being produced at the same rate it's being depleted and the ozone layer will go back to existing in a state of equilibrium (balance) - somewhat anyway, there will always be changes in both the atmosphere and amount of solar radiation so it's never a perfect balance but it'll be close enough (unless we find some other way to fuck up) | 540facc8-68aa-4ff1-9e03-97bbf96d3074 |
c7rdwn | How non-US countries health coverage works and why the US doesn't mimic it. | Singapore has a different system altogether. Citizens have health insurance but pay more of the total bill. This helps keep insurance costs lower due to several factors but mostly keeping misuse or abuse of insurance to a minimum.
Hospitals are required to post all of the prices so that consumers can shop for the best deal. Consumers also rate hospitals on value and service, keeping healthcare quality high.
Singapore citizens rank high for life expectancy globally.
There has been some studies and research done on how to mimic this system. | 517127d5-017f-4ce7-97ae-dc9b8d5196a6 |
c7re9o | Why aren't TV shows that follow criminals, like drug smugglers, forced to hand over footage? | It really depends on the ethics of the filmmaker / journalist. I know in the States we have the Freedom of the Press. This allows Filmmakers and journalists to report on certain topics without persecution. Now this doesn't mean that they cannot be charged with obstruction of Justice for withholding evidence. At that point it's a matter of how much money you have, how good your lawyer is and how strong your ethics are. As a journalist if your source wants to remain nameless it is your duty to keep your source confidential. Prosecutors can get a court order saying you have to give up your source if it is a matter of national security (Thank you Patriot Act) but again what are your ethics. There are multiple journalist who have been charged especially under Nixon, and Trump. What normally happens is if they can't charge you with anything the IRS tends to Audit you, and everyone around you. The government will make your life hell until you play ball. This is all if the show isn't staged, but having worked on a few they mostly are.... | 7e6e5592-94bd-44c7-945a-f3a4126b9cb9 |
c7rjrj | How do they make fireworks spin or spiral rather than go in a straight trajectory? | By making them unbalanced. Imagine balancing the firework on your finger; if it rolls or falls off your finger, or you have to make a lot of adjustments to keep it balanced, then it will tumble (spin or spiral) if you were to replace your finger with a thrust like a little rocket engine. | e89c879a-be59-404c-9d43-e9daa65d3d6d |
c7rpnh | What is happening in our brain when we are reciting stuff? | Your brain does this with all things you have to do a lot. It assigns the task to your subconsciousness to free up "ressources" maybe needed for another task. | d8f0a1b6-e48d-4f3c-bd90-0f2d64a1c103 |
c7rv0p | Gross Anatomy | We have these things called book stores where they sell books. Books are peer reviewed literature, edited, factual information printed on paper that you can study. You can store books on a shelf specifically designed to hold books and refer to them anytime you want. Anatomical books usually have very detailed pictures in addition to text which make studying this particular subject visually stimulating. Try it! | 3c64fcd2-69d3-4dcc-9cca-79afed94f3a2 |
c7rx4d | How did we learn to distinguish between toxic and non-toxic plants and mushrooms, and especially treat some toxic plants so that they become edible? | It was given to sheep, goats, dogs and if it were safe for them we would try. Trial and error | 5e522e1e-1559-4bc6-8c96-7b1bccd7a8c4 |
c7s5t6 | How do pain killers target certain areas? | According to a Youtube video that I watched, they don't. Paracetamol, Aspirin, Morphine and so on do not target the specific painful area. They reduce pain overall throughout the entire body, although the mechanism of those drugs are different. | aa8a1a5f-2b01-412f-a5f8-44dcc155b48d |
c7saz5 | If gravity can bend light and distort images, why isn't earth's (and other planets) images distorted when we look at them through a telescope? | It does, just not in a way that you are going to notice without special equipment. It took a solar eclipse to look at light passing very close to the sun - the most massive object in our solar system - to empirically verify Einstein's theory of gravitational lensing. | d9abe151-de2f-4de2-905e-921372a9f82c |
c7sc6c | What is a copywriter? | Copy is written content without a narrative. So in a company, it is usually a marketing function to generate social media post, brochures or advertising, but can also be an operations or engineering function to write user manuals and the like. | b7dd7775-7806-4cec-b1e7-664a73252cdf |
c7sol0 | What causes the sound (growl) in our stomach when we're very hungry? | What is producing the sound is a mechanism that happens at all times. It is just more noticeable when the stomach is empty.
When the stomach passes digested food into your intestines, it contracts. This contraction makes a rumbling noise. When your stomach is completely empty, and there is nothing to muffle the noises produced, you hear the growling! | 73cbf726-94f3-4258-85a8-d95ce50b6080 |
c7t8gz | If skin cells die and fall off everyday, how do we still have freckles and scars? | The same way we still have regular skin which acts differently in various locations (such as hair growth in some places and no hair in others)— it gets replaced with the same type of cell that is programmed to act the same way.
Some of these things may seem like “flaws” (cosmetically or otherwise) but they are just following the body’s chemical signaling, or genetic makeup of the cells in that location. As far as the replacement cells are concerned you are “supposed” to have a freckle there so it stays.
And when it comes to scars— they form during the (relatively fast) healing process when it may not be possible to fully, or quickly rebuild the underlying structure with the same circulation, muscle tissue, nerve tissue, etc to restore the original appearance and function... so scars can fade over time but there are good reasons why they persist and take a long time to heal. | 36ac1c4e-8ad5-4c77-aa57-26f9705b7010 |
c7tc77 | Why do toenails take longer to grow out than fingernails? | Your toes are the farthest part of your body from your torso. Your torso has the organs that recycle blood by pumping it (heart), replenishing oxygen (lungs), and adding energy to it (intestines).
Since your toes are far away, the blood reaching there has already given a deal of its oxygen and nutrients away before it gets there. Without those, your toenails grow slower than your fingernails.
People with diabetes, a disease that prevents their body from controlling their blood sugar, often experience foot issues because of the poor quality of blood reaching the end of their legs. | af462d74-1cff-4e59-8540-7fa1394b76d6 |
c7tlmf | why do our eyes perceive a lit red/green/blue pixel as white? | We perceive colours based on how much our three types of colour sensing cones in our eyes react to light. White, as a colour, is how our brain parses all three of those types reacting at the same time. In nature, this usually means a mix of many different colours of light, such as from the sun. On a screen, the three colours of pixels roughly match the three types of cones in our eyes, and so we can fake the same sensations that "many wavelengths of light" causes with only 3 | 3213b723-d221-4c51-92b8-cd934622f953 |
c7trqm | How did people calculate the Earth's population? | Each country runs a census. They also know their birth and death rates.
So the earth’s population is a very good estimate because, for example, the last census in a particular may have been 2 years ago and they estimate the population today based on birth/death rates.
All in all, it’s fairly accurate. | e1a11156-bdb6-4fde-bb5c-8a854d58415a |
c7u97k | How do moles (nevi) start growing in your skin? What makes them stop growing? | I’m not skilled enough to give a super ELIA5 version, but here’s a simplified one.
A mole / Nevus is a clump of these things in our skin called ‘melanocytes’ - these are the skin parts that create melanin which give skin its color. More melanin = darker skin. Less melanin = lighter skin.
A mole can be in three different forms - a junctional, a compound, and an Intradermal. Essentially, these tell you WHERE in the depths of the skin they are located.
A junctional mole is the beginning of a mole, and is when these melanocytes sit at the bottom layer of your epidermis - the outermost skin layer. It is usually flat.
A compound mole is when these melanocytes begin to enter into the skins dermis (the part under your epidermis) - this causes the mole to become slightly raised, also known as a ‘papule’
An intradermal mole is when the ‘epidermal’ portion of the mole disappears, leaving all ‘dermal’ cells to sit there. This is usually a raised , dark papule, more raised than a compound mole.
This transformation usually goes from a young age to increasing ages - when it is an intradermal mole, it is (usually) done growing. However, there’s a possibility these benign (non-cancerous) melanocytes can become dysplastic (this is bad!) and transform into a malignant (cancerous) group, which would then cause a melanoma. This is one way for a melanoma to form, another way is totally independent of benign moles.
***EDIT: Some people seem to think it’s ok to seek out medical advice on reddit. It’s not. I am not a doctor, and even if I was, it is pretty difficult to diagnose a skin condition without seeing the skin. Go see a dermatologist or your primary care physician, please don’t go seeking out medical advice on reddit. You never know who is putting out wrong and misleading information or giving advice | dd43ac17-7c69-448d-a602-281b3ae6a4fb |
c7vcjy | Why do some charging cables charge faster than others? | The wires that carry current to the battery can be different circumferences . Bigger ones carry more current but are more expensive. In all likelihood the company that made the one at the gas station didn't invest much in its design. | bf457507-5571-4d87-af8c-86a44d4ecd65 |
c7vro3 | How do fruit and vegetables ripen after they’ve been removed from their original plant/tree? | They are still alive. Their biologic processes continue to function, albeit without the supply of food and water they had before they were picked. | 4358101b-4213-4fb8-be1a-1e7d8dc9a8c3 |
c7w7g0 | How do Radio Waves work? They have always been around? | Radio waves are electromagnetic waves, just like light is and X-Rays are. Radio waves have a larger wavelength than visible light, and they have always existed as a form of radiation just as every other electromagnetic wave has. They weren't used as a method of communication until the early 20th century though. We generate them using antennas that have high currents oscillating in them. | dd90167e-e7cc-4b4f-b84a-3fc968d909d1 |
c7wbc8 | Would making the surface of a channel or river hydrophobic or super hydrophobic change its erosion and weathering speed? | I mean maybe? The water isn't going to float across the top, there will still be friction and such acting on the riverbed. It shouldn't be too hard to test, all you need is some sand and some hydrophobic spray and a source of steady running water.
& #x200B;
Hypothesis: The hydrophobic coating will develop some "gaps" within a few seconds, if we're talking about sand/compacted earth as our base material. These gaps create small sections that are hydrophobic, but have water soaking underneath them. Likely the coating will erode and get washed downstream in larger discreet quantities than if you just let sedimentation move dirt downstream.
& #x200B;
I might be an idiot though, that's the risk you take on the internet. | 48c999d1-330f-434a-965d-69f62b5a2c68 |
c7wq0r | Why can't we use nuclear fission to fuel rockets? | [We can.](_URL_0_)
But putting a nuclear reactor on a rocket is a horribly bad idea. And a nuclear rocket would still use rocket fuel, it would just ditch the oxidizer. | 69a88b2a-67d8-4725-82aa-00ab0443a529 |
c7wv05 | Can somebody explain the escalating Hong Kong situation? | China took over Hong Kong from the British a couple decades ago. Part of the agreement they made with the Brits was that Hong Kong could operate with a separate government and judicial system. China is using a case of a guy who murdered someone and fled to Taiwan as an excuse to push through new extradition laws which allow anyone charged with a crime to be extradited to mainland China. That could include political crimes, so it's basically a free pass for China to disappear people. They disappear people now, but they have to be low key about it. Hong Kongers are not happy, and we're all hoping China doesn't just kill them all like they did at Tienanmen Square. | e680dbb0-3eea-4c66-a1ad-d8e43823aca3 |
c7wzvi | Why do whales, as big as they are, only feast on small sea critters? | Because filter feeding on massive swarms of krill is incredibly energy efficient.
See, large whales aren't all that fast, especially when lounging at food as their lower jaw, almost angled at 90° from their body, acts as a gigantic parachute of sorts that slows the animal almost to a complete halt.
To feed like this, you need something that can't get away, either by being slow or by first coralling your prey in a tight group (see humpback whales), meaning anything decently large is just too nimble to be caught by baleen whales. | 7f2a18bb-438d-4264-97f8-ede137b06022 |
c7yrud | How does the insurance company determine the value of my car in a settlement? | Kia made a lot of Spectras in 2009. The insurance company will look at data on cars that are available on the used car market, mostly tradeins and from places like CarMax. They will try to find 2-3 cars that are about the same miles as yours, and then adjust for differences. It's pretty accurate, as used car prices are pretty stable.
What they don't factor in is that you knew how well your car was taken care of. Some other Kia might have been in all sorts of horrible conditions, and if you went over to test-drive it you'd likely say "this car is junk in comparison to my car". Alas, your car isn't worth that much to anybody else, who doesn't know how you've cared for it, and it's unlikely you'd get more money from your car had you tried to sell it. Private party value is usually higher, factoring in that you wouldn't sell a bad car to somebody at work, so you're not going to get that much. | 238689a2-a019-4378-bc71-b82d377c4489 |
c7yygv | how exactly does the body “burn” energy and generate heat without a fire? | You are right, the actual "burning" of energy in the body is more or less the same chemical reaction that a flame gives off. Normally a combustion chemical reaction requires "activation energy" to occur, it has to be heated before it can occur but gives back this and more energy at the end of the reaction.
The trick is however that we can more or less remove/lessen this activation energy requirement by use of a chemical called a catalyst. A catalyst doesn't really take part in the reaction itself, but it helps the reaction along by doing things like positioning the elements in an ideal place for the reaction to occur. For instance a classic example of a catalyst is found in your blood, a protein aptly named catalase. Catalase breaks down hydrogen peroxide, hydrogen peroxide normally breaks down on its own but also does so faster with added heat. Catalase will do this without needing heat to be added beyond your natural body temperature. This is why if you ever pour hydrogen peroxide on a wound, it foams, that is the hydrogen peroxide decomposing into hydrogen and oxygen by use of the catalase in your blood. The popular experiment elephant toothpaste also does this, but with a different catalyst, potassium iodide.
The process that breaks down things like sugars into energy is more complicated in your body of course but the principle of a catalyst applies. | 514b1017-bd11-4012-a261-510a96264949 |
c7za1i | how paul george can snap his leg in half and recover to be an mvp candidate but people are wondering if KD can return from an Achilles tear? | The difference between the two is that George snapped his bone, while Durant tore his tendon.
Bones in general are known to break apart and reform, with the right care, and are commonly known to fix themselves (e.g. broken arm in a cast). However, the Achilles’ tendon (tear) doesn’t carry its own robust (strong/healthy) blood supply meaning that it can’t heal by itself efficiently, unlike a cut or bruise which heals in a matter of days.
So, the only two ways fix a tendon is extreme physical therapy, with very little to no activity on that tendon, so as to let the tendon heal by itself over a long course of time, or surgery.
However, operating on a tendon is very difficult and the tendon itself almost never comes out the same. Plus with the additional time or no activity in both treatments, Durant may have a hard time coming back and recovering lost skills. | 7efd5227-c8da-4008-92a9-04089829c7b9 |
c7zy6n | How does whistling produce sound? | There is some friction between your lips and the air that passes through them. This friction can cause your lips/cheeks to vibrate kinda like a violin bow on a string. You can change the note by changing the volume of your mouth, like shortening a string by placing your finger on it. | 7d68a0cd-9ada-4741-8dce-2217a701e0be |
c803bh | What is Gradle? | Gradle is an automated build system. It takes a change that you made in the source code and builds a new version of the software, bringing in all the 3rd party libraries and modules dependencies, and runs tests that you define to make sure your software is doing all the behaviors that it supposed to be doing. | 39a289f8-10b7-428d-a7cb-6418cb43334e |
c805z7 | Why where Honk Kong protestors waving the British flag when they stormed a government building? | Oh so Hong Kong used to be a British "overseas territory" (colony) (taken in the Opium Wars of the 1800s) and was ruled under British Law until 1997 when China took it back. It's still run under British law for the most part, but China wants to change that. The residents of Hong Kong do not want to change their legal system, especially because it would mean they couldn't criticize the Chinese government. So while i'm not 100% sure, it's probably representative of the legal system they want to remain under.
src: have history degree from around the time Britain took Hong Kong, and took classes in Chinese history, but not an expert in contemporary politics | 4ad156ed-a849-4f5f-b37f-ed77db7c7acf |
c80qu0 | What would happen if you got a tattoo in space? | > Would the ink make it onto the skin?
"Make it"? The ink is injected under the skin with bundles of needles, I don't see why microgravity would prevent that.
> Would the ink stay on the skin if it did work?
Again, ink under the skin isn't prone to floating away gravity or no gravity, so I would suspect it would stay put.
> Would the healing times be different?
I believe people tend to heal slower in free fall for reasons I'm not clear on. But overall I suspect it would be similar. | c992cb9b-d3ca-4ec5-97bf-f667895325f9 |
c80ryh | How do Captchas know if I'm a robot or not? | IIRC a captcha collects data such as mouse movements and speed of input and such. I may be wrong though | c6540d7b-63b2-4b96-83ca-e092a387b5c5 |
c80x61 | What is the difference between Inkjet, Laserjet and Matrix printer? | An inkjet printer uses ink and is better for low volume (amount) printing and is normally better for home owners.
A laserjet printer uses toner (dry powdery substance that gets electrically charged [stuck] to paper). This printer is much better for high volume (amount) printing and is seen much more in office settings.
A matrix printer is most simile to a typewriter, meaning that it has a ribbon or sheet that is struck by a series of “hammers” against the paper. | 1721a451-8314-4ca4-acf0-685ac1e62bd0 |
c81if9 | How does Congress actually dispense funds? | Questions about the US are generally better in r/askanamerican, or you could r/ask_politics. | 607821ef-4fa8-4fcf-aa79-06399b2fb511 |
c81v6i | Why don’t animals need to brush their teeth after eating, but if humans go even a few months without proper dental care their teeth start to rot? | Our diet contains waaaaay more refined sugar than our bodies are meant to handle. Its specifically the refined sugar that causes us so much teeth issues- even humans had better teeth prior to our diet working this way. | 75e90a3e-3d7b-47b6-b061-b7934262b2e2 |
c81zd1 | Why does a punch to the chin knock one out but a punch to the head might not? | It’s about getting the skull to snap back. You get knocked out when you brain smashes against the inside of your skull, and a punch straight to the head probably won’t generate enough rotation to do that, but a punch to the chin will rock your skull backwards and your brain will hit the back of your head. | 71cbfb80-2b69-49c4-bd13-f577aa8309c6 |
c823bp | How can a usb hub know how to route data from multiple sources into one usb hub? | All communications are encoded with the source and destination. The data is sent to all devices on the hub. Everyone except the destination device ignores it. | 0c5ac5df-3cc8-4e4f-bd0b-b6b098d2a98f |
c8267o | What is the difference between gold-backed currency and fiat currency? What is purchasing power? | There are really three kinds of money to talk about:
* Commodity money
* Representative money
* Fiat money
**Commodity money** is a money whose value comes from what it is made out of. So gold or silver coins are commodity money.
**Representative money** is an intrinsically valueless currency (i.e. a paper certificate) whose value comes from what it *represents* -- typically a share of a commodity (such as precious metals like gold and silver) that is held in reserve in a stockpile. Gold-backed currency falls into this category. Up until the early 20th century, if you wemost US dollars were gold or silver certificates that (theoretically) could have been exchanged for an amount of physical gold or silver held in reserve at Fort Knox.
**Fiat money** is an intrinsically valueless currency (i.e. a paper certificate) whose value is determined by (a) the government that issues it and (b) the people who use and exchange it. The value is often guaranteed by the issuing government, and, thus, is only as stable and valuable as people's perception of the stability and value of that government/country. In modern times, nearly all currency is fiat currency.
Increasingly, though, currency (coins and paper notes) is irrelevant. Today, most transactions take place through an exchange of information among trusted institutions. When you swipe your credit card, that's an exchange of information between you, the vendor, the vendor's bank, and your credit card's issuing bank. The monetary value is still measured in the same units as the currency, but no currency is involved. It's not hard to foresee a currency-less future.
**Purchasing power** is a measurement of what goods/services can be bought for that money.
Say, for example, it's 1950. You make $1/hour at your job. With that $1 you can buy ten candy bars that cost 10 cents each.
Fast forward to 1990. Because of inflation, a single candy bar now costs $1 instead of ten cents. So the *purchasing power* of a single dollar is now 1/10 of what it was in 1950. Back then you could buy ten candy bars for a dollar; later you could only buy one for a dollar.
However, it's important to understand that purchasing power is, by itself, not a very meaningful statistic because it has to be compared against wages. In 1950 you were making $1/hour. If in 1990 you were making $10/hour, then the value of one hour of *your labor* could still be measured as the ability to purchase 10 candy bars. Your purchasing power would have remained flat.
This is why it's such a problem when wages don't keep up with inflation. Let's say in 1990 you're only making $7/hour. So one hour's worth of labor only nets you 7 candy bars. Since back in 1950 your $1/hour wage would net you 10 candy bars, you're worse off than you were back in the past. | 3b246d3d-a854-483d-8c62-48303115124d |
c82c5q | Why are insulated cups made from seemingly highly conductive materials like stainless steel or aluminum? | Oh I think I actually know this one!
Okay, so there's actually three layers in the cup: an outer layer of metal, a vacuum layer, and an inner layer of metal. You want to use a metal that doesn't "off-gas" (i.e. release gas into the vacuum) after you seal off the center layer.
You want that vacuum to be as empty as possible, because if it's empty, you can't transfer heat through conduction or convection, so the heat transfers very slowly into/out of your liquid. Having the surface be reflective also reflects most of the radiation back into the liquid (if it's hot) or the environment (if it's cold). This is also the idea behind Dewer flasks, except that they use reflective glass (which is even better about not off-gassing). However, if you drop a Dewer flask, they have a nasty habit of exploding. Loudly. Steel doesn't. | 45c5c609-1887-4c9f-aeff-c8cc9ff49f8b |
c82dqo | Why do glasses always get dirty,almost greasy?Do dust molecules naturally stick to the lenses even though I take care of them? | Glasses get dirty from a variety of things, most commonly from touching it. While you may take good care of them, any touch to any part of the glasses may have an affect on the lenses.
If you tend to have oily, or dry and flaky skin, then your glasses will smudge and get dirty easily. Same goes for if you wear makeup or if you apply lotion to your hands or face. Additionally, if you have long eyelashes, those eyelashes can rub off onto your lenses.
Most lenses should have some kind of resistance to smudge or dust particles if you have a good anti reflection coating on it. If you do, then just make sure when you clean it to clean it carefully, as this layer could come off.
Basically, lenses get dirty from everything, whether consciously or not, and if you have a daily habit of cleaning them then you should be alright. | 108d6b1f-88bf-4e54-a475-a9389ce02400 |
c82f94 | why information is entropy | Let's say there exists an imaginary universe where there are only five atoms:
> 00000
Those atoms are all the same, there's no differentiation, so that system is very high in entropy. Just as in physics the universe tends toward an entropic state where everything has cooled off and is the same temperature, our little imaginary universe is equally uniform and unvaried. If you were to predict the state of a sixth atom you could have a high probability predicting it would be "0".
Now imagine a slightly different system:
> 01101
Differentiation! This universe has more information in it. It becomes harder to predict whether that sixth atom will be a "0" or a "1".
Let's try another one:
> 04q%👠N
Holy crud, that's a lot of differentiation! So, *much* less entropy. It would be *really* hard to predict what the next atom might be.
High entropy systems are deterministic, redundant and predictable. But this means they carry very little information, and, thus can do very little work. Low entropy systems are chaotic and unpredictable. There's a lot of information -- i.e. a lot of differentiation. With that comes a lot of potential to do work (e.g. create meaning), but it might take a lot of effort to get that out of the system.
In reality, most information systems fall someone in the middle. Too chaotic and unpredictable, the effort to get any information out of it is immensely difficult and the potential for an error in transmission is high. Too redundant and deterministic and you can't do many useful things with the system ... but you can be certain it's error-free, if, for no other reason, than its all the same!
Want a good example? Look at written language. Check out this sentence:
> Y cn prbbly rd ths sntnc vn thgh thr rnt ny vwls.
If you're an experienced English reader, you understood that. Why? Because in English, most vowels are redundant. They're there to provide you with more certainty about the meaning of the *other* bits of information that make up words. Vowels, therefore, are high in entropy.
That sentence is still intelligible, but because we've removed redundant (i.e. high entropy) letters it's leaning much more to the chaotic and unpredictable. It takes more effort to get meaning out of it. And you're certainly more likely to experience an error in transmission/understanding with this lower entropy version of the sentence. A system that is too differentiated would appear totally random -- you can't get *anything* out of it. Sort of like universe 04q%👠N above! | 204d1735-3289-4ff6-9895-2daa7e33c9d4 |
c82mv2 | How does closed captioning work for live television commentary? | Yes.
Someone (called a stenographer) is usually typing along as the people talk. So there's about a three-sentence delay between what someone says and when it shows up in the captioning.
If they mess up, it usually just gets put up as-is, and you might see active backspacing, because it's more or less a live-feed.
You also need to understand that stenographer's computers don't have letters like yours, but sounds (I learned this on LegalEagle). So the typos look different *and* they usually type faster. | f4576847-37f6-460f-949b-36e56abd5b5d |
c82qcd | Why are thing (like mountains or trees) darker when close, but then brighten as they fade into the distance? | Basically the more distance between you and he mountain, the more light pollution there is. The light “disrupts” the true color or the light reflecting off the mountain.
The same thing is true for stars. If you live in a big city, you can’t see the stars because the light from the city disrupt/override the light from the stars. | 8e0da93a-518a-415a-b51c-64dc7007582c |
c832yd | How did some fruits come to have multiple varieties? eg. granny smith apples and gala apples or benishan mangoes and raspuri mangoes | The same way German Shepard dogs come in all those fur patterns and humans come in a spectrum of skin and hair colors. Random mutations produce small variations, and coloration is a frequent mutation.
Apples are a special case, as apple seeds don't breed true. If you plant Granny Smith apple seeds you don't get a Granny Smith apple tree. Apples are propagated by cloning, and all the Granny Smith apple trees are clones that are almost identical to each other. | 2da4ea34-3e26-4692-9c98-a048f1312431 |
c83evf | How does the brain store words in multiple languages | This one's quite interesting since we don't really know how the brain stores words in one language in the first place, but our current best guess is that they are stored in a mental lexicon which is like a spider web connecting different words of same categories, be it word type, semantics, same prefixes, suffixes etc.
There are two theories regarding multiple languages: either your brain just stores concepts and links them to the words in both languages, or you have two of those webs which additionally are connected to each other via translations. | 1129f2f8-1172-492e-9583-2adb9cd3e4d9 |
c83h6u | Why do certain hairs on our body stop growing when they reach a certain length, yet others can grow to be very long? | I teach puberty classes to 5th and 6th grade kids, and this is one very common question they ask. My joking response is usually something like this:
"Well, we would look pretty funny if our armpit hair grew as long as our head hair, wouldn't we?"
The phrase to research here is "terminal hair length." What that means is, in every follicle that produces hair on your body, the cells are genetically programmed to only grow that hair for a certain length of time. The follicles on our scalp let the hair grow for several years, while the follicles on our legs and arms only let the hair grow for a few months. | e416a29f-4161-43e7-84df-2f6a7f807f51 |
c83te4 | how do fruit flies sense and congregate when there’s expired fruit / something sweet around ? Even when there are closed windows. | sorry about this.....
& #x200B;
Fruit fly larvae often come in \_on the fruit\_ and then subsequently hatch. If it helps you mitigate that nightmare, they also continue to hatch in places like garbage or sinks / disposals.
But..for the most part, the "expired fruit" has this aggregation because sufficient time has passed such that the fruit fly that are gestating on that fruit have hatched.
Enjoy your fruit! | 8e0ee4eb-6cfe-440c-9269-0c73417c3adc |
c83uzf | How are so many nuclear weapons regularly tested if we know what consequences they cause? | There are not regular test of nuclear weapons today. Non of the major nuclear powers have tested there weapons for a long time.
The last US test was in 1992, Russia(USSR) in 1990, UK in 1991, France in 1996 and China in 1996,
& #x200B;
After that only India and Pakistan in 1998 and North Korea 2006-2017 have tested nuclear weapons. For Pakistan and North Korea it was there first test ever so the needed for validate there designs. India had a single test back in 1974 to send the message to China and Pakistan that thy could developed nuclear weapon if it was needed and after
So the statement that there is many regular test today is not correct.
& #x200B;
Most test in not to determine the destructive effect of nuclear weapons even if there was test back in the 1940-60 for that but to validate design of nuclear warhead and to show that they will work even if stored for a long time. Since the Partial Nuclear Test Ban Treaty back in 1963 there have not been any test above ground so no test after that is to determine effect of nuclear weapons on the surrounding area but to show that the design works as expected. | ca9cc310-d3d4-4d28-864e-c92ad93fedee |
c84428 | Why cows are attracted to and come calling to unique sounds like saxophones, burping, etc made by humans when normally they would avoid humans? | Cow do not "normally" avoid humans. They are fully domesticated animals that have been bred to tolerate and depend on humans. Unlike wild animals they do not have a fear of humans.
In the specific scenario you are talking about they have been trained that those sounds occur when feed is being put out or has been put out and so they come to what is effectively a dinner bell. | c7119779-288f-4d73-a879-00e8825e23c6 |
c84ii5 | How do nonverbal toddlers get tested for vision? | They use an autorefractor. Shine image of a balloon onto the retina. Use a camera to look thru the Iris and see how focused the picture of the balloon is. | a33f7023-a9ef-48a3-a3ad-b820322fb746 |
c84nen | What’s the difference between a mountain’s height and its prominence? How are each measured? | Height usually refers to the height of the mountain above sea level; basically, what is the difference in height between the peak of the mountain and the average sea level below.
& #x200B;
Prominence refers to how much the peak of a mountain stands out from the surrounding landscape. Technically speaking, it's the difference in height between the peak of the mountain and the lowest contour line you can draw around it without including any other peaks. | 6366ced7-bc7d-4bbd-a9fc-91ad0a53349c |
c84ty8 | what do people who speak different languages hear when someone speaks English? | It sounds just like what you hear when you hear someone speak in a language you don’t know. You can tell they are saying something that means something because their voice is controlled and their body language will tell you they are not just making up sounds like a crazy person. When I hear American English vs United Kingdom English, American English sounds like the mouth is more open so the words are more full sounding. There is a great video online that demonstrates what English sounds. The video uses a mix of English words and gibberish, but sounds like how an American English speaker would. This is what English would sounds to someone who doesn’t know English. The video can be found [here](_URL_0_) . | f47effe0-a0d9-44de-82d3-449dddff243f |
c84zy2 | Why does touching the bulbs from headlights damage them but most other lightbulbs are fine to touch? | To sum up, you leave oil from your fingers after touching a halogen bulb. When you turn the bulb on, the spot with the oil will heat up more than the rest of the bulb and can also cause the spot to warp and crack. All of this will cause the bulb to stop working early. This extends to any halogen bulb, car or house. | 36c3fe57-5eed-4274-9e7a-e4dedbd3355d |
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