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c3zswz | Why do humans kiss? Like why is it that specific body part? | There are a lot of nerve endings on your lips to protect you from hurting yourself while you eat, so in the right context it can feel good. It's likely a learnt behaviour originating from when parents would pre-chew food for their babies and spit it into their mouths, how romantic. | f03f14eb-25f9-4f4a-92f6-aa2f53078d7c |
c408p1 | What would happen if the sun disappeared? | We wouldn't know it had disappeared for around 8 minutes ish. After 8 minutes we would no longer receive light from the sun, nor would we be affected by the presence of the sun (as gravitational waves travel at the speed of light meaning that we would still be under the effects of the sun's presence for a few minutes.
After which earth would likely continue on a straight trajectory without the sun, the surface would cool with exceptions of places with extreme geothermal events. The lack of light would cause plants to just die out and as a result all remaining mammals would all die out due to the lack of oxygen. The oceans would freeze over and beneath the thick sheets of ice would be a dark yet terrifying ocean filled with creatures living off of the energy provided by geothermal vents just as they are now. | 3e49affa-ff78-4a2a-b3e4-b6a1c6897da2 |
c40arb | What is happening inside of the human body when someone is faced with something that makes them "squeamish" and causes them to pass out? | When a person experiences extreme stress or emotion, it can trigger a certain part of the nervous system or a widening of the blood vessels, both decrease blood pressure. If you don’t have enough blood going to your brain, then your body auto shuts down to try to save your life. Things that may cause you to faint: encountering your phobia (blood, needles, spiders), hysteria (Michael Jackson, the Beatles, Beyoncé), sensory shock (seeing your parents doing it, seeing your grandparents doing it). Fortunately, you can use smelling salts (containing ammonia) to shock (irritate with harsh smell) other parts of your body to trigger waking up. | 059ec5dd-3447-43dd-b58a-4336157c2e39 |
c40c9d | What stops websites from taking your Credit Cards? | Nothing stops them from using your card, but you can see how much money went where in your banking app. If you bought a shirt for 30$, and in the app you see that 30$ went to a shirt seller and another 50$ went for something you know you didn't buy, you can call your bank to block the card and see if you can get your money back. Also, saving sensitive data into database like passwords and card numbers is usually done by encrypting it. Web developers who made that website can probably see what's in a database, but they can't read it since it is encrypted so it's useless to them. Secure checkout can also mean that your card data is encrypted while traveling from your pc to the server, so no man-in-the-middle attacks can occur (no one can intercept and read card numbers before they reach the server). There's some more stuff going on which I'm not very familiar with nor good at explaining it, so I hope my answer covers some basics. | f17d916e-cdd3-411d-80f4-cc2b7f3b234b |
c40f8j | How do radio stations know how many listeners they have? | They take a small sample of random people and track them using computers or survey them. I was once part of Neilson ratings. I was required to wear a device that listened for a tune from the radio or TV to indicate what I was watching. | e522106b-77ac-40ac-bda9-502c2a33bc2f |
c40yfo | How did we get to the moon and back? | It's trivially easy to measure the distance to the moon. This was first done accurately over 2000 years ago by Hipparchus in the 2nd century BC. He used basic trigonometry for that. Obviously his measurements were refined in the following millennia with better optical measurements and in the 20th, century radar and lidar, but his initial measurement was remarkably accurate. So no, we did not have to send probes to the moon to "guess" how far away it was because we knew for a very long time.
As for whether or not it was safe to land, that was more open. NASA was actually quite worried about that in the early 1960's. We knew the moon was sold because we could measure its mass, but we weren't sure if maybe there was a thick layer of dust on the surface that a lander could sink into. A lot of flybys and measurements from spacecraft told it it was probably safe, and that was confirmed by the successful landings of the 7 American Surveyor probes between 1966 and 1968, and the 2 Soviet Luna landers in 1966. Spacecraft also took a ton of pictures to survey potential safe landing sites for manned missions. This was one of the goals of Apollo 8, the first manned mission to lunar orbit.
As for getting off the moon, it's actually even easier than launching off the Earth since there's no air which means no atmospheric drag, and it's much less massive, which means less gravity, which means you can use a much smaller rocket. The biggest hurdle was designing the lunar module ascent stage to be extremely reliable, because if if didn't work, the astronauts would have been stranded on the surface and left to die. | 1e958a0b-2fc9-403b-9f14-89029d641459 |
c41dwk | How do musical roads work? | Car wheels make noise when they go over the notches in the road, the bigger the notch the lower the pitch, and vice versa. | cd125995-ecfb-4f85-97ce-b15f5aebda99 |
c41mag | what determines whether what you eat gets used, stored or pooped out by your body? | Different parts of your digestive tract break down the food into simpler nutrients, and then absorb them. Once absorbed those nutrients go into the blood stream and are then taken in by the cells that require them (for use or storage). Anything that isn’t absorbed (stuff your body can’t break down or use) comes out as poop. Poop is just ‘filler’ and whatever nutrients there were too much of in that batch to be absorbed by the time they pass through the relevant area of the tract. | 3bbb2c8a-789a-4558-92db-eab0afee1c60 |
c41nco | Why does burning the product of Direct Air Capture not result in a net balance of CO2 in the air? | It's not ideal. Certainly not as good as just running DAC and *not* burning the result (though I doubt that would be commercially viable). That said, it's still better than burning fossil fuels. In the case of DAC, CO2 is removed from the atmosphere (where it's a problem) and then eventually returned to the atmosphere. In the case of oil, the carbon is removed from the ground, where it's harmless to the environment, and turned into CO2 in the air, where it causes global warming/pollution.
Basically, burning fuel from DAC gives (approximately) a net zero change in atmospheric CO2. This is better than fossil fuels which create a net increase in atmospheric CO2 (on any time scale outside the geologic).
The comparison to biofuels is more interesting because they too have (theoretical) net zero CO2 emissions. I'm not an expert and it's a new technology, but I'd assume that the advantage of DAC would be lesser land, water, and possibly energy requirements for the creation of the fuel than biofuel production. | 6b62c6fb-bc00-4002-ba63-06901c4d3561 |
c41x21 | Why are there clouds in the forest? | These usually happen in quite dense forests and more often near mountains or similar geographical features that will blow cold(er) air over the forests. The dense canopy acts like a greenhouse trapping a lot of moisture and heat. As some of that moisture escapes the canopy it meets with the cooler air and condenses. Under certain conditions (after rain being ideal for it) the amount of moisture escaping is enough that when it condenses it is able to form clouds. | 4c8d35d2-946b-46eb-9969-00a91132655f |
c41zb4 | How do digital cameras focus by me just holding down one button? | They analyze the data coming from the sensor and adjust the focus until they get the clearest image.
When you're out of focus, the level of similarity between pixels is high, as the image comes into focus, the similarity between pixels drops. The camera adjusts the lens until it finds the point with the lowest similarity between pixels. | 20725444-028a-48d1-9029-86cc5e19c42f |
c42cz2 | How does communicating to rovers all the way in another planet work and how can we control it from so far away? | NASA uses the Deep Space Network, a series of very powerful radio transcievers placed around the world. These powerful radios are spaced out around the world so that, no matter how the Earth rotates, there will always be a radio pointed the way you need it.
To communicate with a Mars rover, for example, a transmission will be sent from the DSN out to the rover. Because Mars also rotates, we can only communicate with the rover while the side fo Mars it's on is facing the Earth.
Because of the distance between Earth and Mars, it can take between 3 and 22 minutes to go from Earth to Mars (and another 3 to 22 for the response to come back), so NASA has to preplan every move the rover makes in advance, then wait up to an hour for the rover to let them know how it went. | ee744c7f-a290-49ca-adc8-3aa7225a1e6f |
c42fjj | Why do deodorant , or any other aerosol cans , get colder the more you spray them? | There was just a [really great MinutePhysics](_URL_0_) video on this exact topic | 8862a87a-265a-45c5-82aa-afb489300ee3 |
c42nzx | How do TV stations know how many viewers they have for their ratings? Isn't it just a signal that is being wirelessly broadcasted? | an expert will give better insight.
but short answer: They dont..
it was all survey/research based. ( [_URL_1_](_URL_0_) )
it was done to the best of capabilities all over world. sometimes automatic . sometimes manual. it would be seen at what times what channel is being watched. and a calculated figure was attained | e9279001-a1e5-4de8-af0e-ec95bafa123c |
c43ook | r/RoastMe | From what I've seen, there are two types of people requesting to be roasted:
* Those who want a laugh and are willing to have one at their own expense.
* Those who think they are "roast-proof" (these people are nearly always wrong). | 94ebe951-37fc-4393-bd43-8f31c40fc3f4 |
c43t7s | How does fast(Flash?)charge work? What is limiting us to charge our phone/electronics to be fully charged in minutes? | A few reasons why fast charging is difficult.
1. Heat generation in the battery . No charging process is 100% efficient, they all make heat (except flow batteries which charge by replacing the electrolyte).
2. For lithium cells, overvoltage damages cells. In order to make higher current flow, a higher voltage is needed. Lithium cells are damaged by voltage over 4.3V. Their chargers use a constant current at first which can be fast, but once the voltage reaches 4.3V they have to stay at 4.3V for the rest of the charge. The current then declines as the cell reaches full charge. This is why 0-70% is faster than 70-100%. Tldr : you can't fast charge beyond around 70%.
3. Fast charging requires more current which needs either thicker wire or higher voltage along with conversion circuitry. 120W at 4 V is 30A. That is not possible in a thin wire or small connector. Existing USB uses higher voltage to limit current. The phones have conversion circuitry but scaling that up to 120W takes space and dissipates heat. | 1238542f-4456-447f-9b04-7f0560b64650 |
c43xac | How do people pass away from natural causes at such an early age? | Could you clarify what you mean by natural causes? | a2cb55b6-0d9f-4820-922f-7f4a733ec36a |
c4423w | It seems like we only cure pork into ham, but we don't treat any other meat the same way. Why? | Beef jerky is basically dry cured beef. Fish is often spoken and in northern countries also salt cured or dry cured. | c44298d3-fd00-4c09-81b5-117f1458ac81 |
c45022 | Why does getting a massage make you feel good? | A few reasons. Firstly because massage relaxes the muscles, reduces discomfort/ pain (by pain gating mechanism through the spine), promotes blood flow and helps to strengthen the muscles and joints. It's beneficial effects also include endorphin release in the brain, which is similar to morphine (= relaxation, well being, bliss)
Secondly, massage has evolutionary roots. Grooming is part of our ape + developmental past and it clearly *still* helps with personal/ group bonding and the additional psychological benefits. | e83bb67a-701a-437c-93c2-1a635fdbffba |
c4579x | Is there an explanation/reason that the human mind has an easier time remembering negative emotions and events rather than the positive ones? | I had a professor explain to me that evolutionarily speaking it makes more sense to remember negative experiences than positive ones. Negative experiences leave a more lasting affect on the brain so we remember to avoid those situations, people, dangerous places etc. | 335159e1-9293-412e-85de-7c4e380e67b6 |
c459uo | What is the noise someone “hears” when they have tinnitus? | I have tinnitus. The easiest way to describe it is a very high pitches “eeeee.” Think movies where someone survives an explosion, or those mosquito noise apps on your phone. | f5238ba1-f6b6-4380-9505-1b9c40250e8d |
c45dol | Why does orange juice from concentrate taste so different? | OJ from concentrate is mostly sugar, sometimes with pulp. It’s concentrated by cooking it down (much of the time) and a lot of flavors are lost that way. This is counter acted by adding in some orange oil or other flavorants naturally found in oranges. Unfortunately, they are usually missing flavors and are not always in the right proportion. | 43106188-1bea-4837-9aa2-918b42cf51eb |
c45imi | How do we decide what is "up" and what is "down" in space? How do we decide the orientation of something, is it arbitrary or do we decide it relative to something else? | There's no objectively correct orientation in space. Images of the earth are usually aligned so Earth North is up, but that's because it would look wierd if it weren't.
I suppose you would orient yourself to the orbital plane of the objects you're seeing. So if you're looking at a model of the solar system, most things orbit in a flat plane, so orient your image to that.
If you're in interstellar space, you could orient yourself to the galactic orbital plane.
If you're between galaxies there's literally no correct answer. | 04bdc589-dc05-4e6b-8e6b-49b0ef770594 |
c45j8x | Why do clouds have balls and stuff on the top but look completely flat on the bottom? | The sky is made up of various layers and currents of air with differences in density.
A cloud is water vapor that 'floats' on a layer of high density air, the bottom is flat because it gets pressed against this underlying layer by the weight of all the vapor on top. | 855e4fe6-6598-4b85-a67d-75f555408a67 |
c4606e | Why is the research done at high energy particle accelerators important for mankind? | Particle accelerators help scientists understand how the physical world works. Theoretical physicists can construct models of quantum mechanics and particle physics, but without experimental equipment like particle accelerators, they're flying blind.
High level physics is how we get the super high density computing in your smartphone. Or the radiotherapy to treat cancer. Or atomic clocks that let GPS work.
There are also spinoffs that come from developing the computers to analyse all the particle physics data. All websites run on HTTP, which was developed at CERN. | 6f6e4c16-5ddc-4f3a-a6dc-647bc4eb3ce2 |
c465yl | what is the difference between introverts and lack of social skills | Introverts are not necessarily antisocial/lack social skills. Being introverted means that you get “charged” so to speak by being alone, while extroverts feel energized by being with others. Some introverts are outgoing and some extroverts are shy. Social skills are more like how you interact/read social cues/navigate social situation. Hope that helps! | 05c68a1c-4c93-48da-977c-d0ae43f6eac4 |
c46f3y | - Why, after rubbing your eyes, it takes a few seconds for your vision to return but not when you hold them closed? | If you rub too hard, you can disrupt the tear film that covers your eyes. Your eyes work the best when there is a uniform coating of tears over it. When the film gets displaced by rubbing, things will look blurry until you blink a few times to restore the tear film. People with dry eye have a hard time restoring their tear films.
Also if you rub really hard, you can cause pressure changes within the fluid in the eye. This can cause misfires in the light sensitive cells of your eyes which can take a few seconds or longer for your vision to return to a normal state. Make sure you are not rubbing this hard since it can cause permanent damage to your eye sight. Glaucoma, an eye disease that causes blindness, can be caused by too much eye pressure over long periods of time. | cc2c7583-2cbd-46a9-92ae-ba1d76bfc5c4 |
c47bw7 | What is behind bodily reactions to sickness? | > It sometimes seems to me that the runny noses, headaches and fevers we get when we have a cold or something are completely arbitrary.
Nope. Runny nose helps to flush out the germs. Headache is part of the inflammation response to infection.
> What does the body hope to accomplish by turning up the heat
Most bacteria can only survive in a narrow range of temperatures. Those that make us sick are most comfortable at ~37°C/98.6°F. Anything hotter and they literally start to unravel (this is called *denaturing*, which is where the structure of proteins changes to something the organism can't use).
> making my head hurt
Tissues in the body swell up when they're inflamed. Headaches can also be caused by dehydration.
> blocking up my sinuses
The body normally only uses one nostril at a time for breathing. Sinus congestion is part of the immune response. | 4e33081d-9971-472d-ac25-5280ac1c8a71 |
c47rsa | Why do animals sometimes just stare at nothing? | When an herbivore "stares at nothing", they are typically watching a broad swathe of territory, attempting to register any motion within that field. When a carnivore stares, it is usually because motion has already occurred and they are attempting to isolate the source. | d598a36e-5af6-4b97-bb84-24667035606c |
c483fx | Why is liquid nitrogen cold and is it possible to make it warm? | Let's take water as an example here for a moment.
Water is a liquid at room temperature, but if you heat it up it becomes a gas that we call steam. If you make water cold it becomes a solid which we call ice.
These changes in state occur because of temperature.
Nitrogen gas undergoes the same changes in state as water, but at different temperatures. At room temperature Nitrogen is a gas but in order to make it a liquid you have to cool it down... a lot. You have to get Nitrogen down to -196 celcius for it to become a liquid. That's why liquid nitrogen is cold, if it warms up it becomes a gas. | 438ca3ea-1c73-4ca9-a228-a86f83bdfa0f |
c485h8 | Do subprime loans hurt credit score? | Subprime loans are reported by business name. They don't say Loan, subprime 1 of 1. They report the name of the issuer and your payment history, loan amount, and paid off/delinquent/etc. | bfcefaba-ae92-42fe-b51a-11f102d9ab1a |
c48ln2 | The Grand Unified Theory of Physics | Classical Newtonian physics ( the behavior of big things and forces acting on them) does not work well with Quantum Dynamics ( the behavior of atomic particles). The Grande Unifying Theory of physics is a still ongoing effort to find where these two theories of physics agree with each other basically to find what is causing them to be so disjointed and how to equate for it in equations that could work for both Quantum mechanics and Newtonian physics. | ff741c17-ba94-49e7-80ea-5c5a4609197b |
c48pcv | How can the tides of one place have a difference of one or two feet, while in some places the tide difference is nearly forty feet? | If there was no land at all to get in the way, the change in tides would be highest at the equator and basically zero at the poles, but when you have continents getting in the way of a planet scale wave that wants to follow the moon around, the inertia of the water, and restrictions to flow, have a huge impact. | 70a7b8d3-a66b-4f6e-9e18-8f260dadeb58 |
c48q6g | Why can't we see the dark side of the moon from the Earth? | Didn't you just ask this question?
Anyway: We can only see the *near* side of the moon. The *far* side is what we can't see. The reason for this is that the moon rotates around its axis at the same rate it rotates around the earth, so that the same side of the moon is always facing earth. This is not a coincidence, it's an astronomical effect called "tidal locking".
Technically speaking there's no "dark" side of the moon, just like there's no "dark" side of earth - at any given moment, half of the moon is lit by the sun while the other half is dark, just like earth. | 3ae60f22-14cd-42f3-85cb-afd68a390505 |
c491ua | Why do bug bites slightly swell up and become extremely itchy? | Histamines, which are a chemical released by your immune system, flood the area and increase blood flow. It’s the histamine that’s making your skin itch, which is why you take anti-histamines to tell your immune system to calm down basically | 307aeb40-0f4c-46e9-8c78-bf6a604ced67 |
c493lc | What is the cause of the 11-year long sunspot cycle of the Sun and how does it work? | The inner part of the sun spins faster than the outer part. Think of it like if you were twisting some Taffy . Well it gets twisted an twisted more and more at which point the poles flip. And it takes about 11 years for that twisting to flip the poles. That's what I remember from my college astronomy class | c2554c70-47bf-4592-913e-ff587aedb4fe |
c49cua | How does defusing a bomb work? | The problem with answering this question is that there is no single way to design and fabricate a bomb.
By far the simplest method is to intentionally blow it up with the surrounding area evacuated. Robotic vehicles in the military are design to do this. If the situation calls for actually defusing the bomb, then a bomb disposal team may try to take x-rays of the bomb, review the innards and formulate a plan to defuse the bomb. The exact methodologies they may use are trade-secrets for obvious reasons.
More sophisticated bombs may be undefeatable however. For example, the [Harvey’s Resort Bomb](_URL_0_) of 1980 featured:
• 30+ switches on the exterior that had to be flipped in a specific sequence to lengthen the timer and disable certain sensors.
• A tilt sensor. If the device was moved without staying level, the bomb would explode.
• A float valve. If the device was flooded with water in an attempt to disarm it, the bomb would explode.
• Spring loaded screws. If any of the screws on the exterior were turned, the bomb would explode.
• Pressure sensors. If you tried to pry the top off, pressure would be relieved and the bomb would explode.
• Conductive metal foil. A thin metal layer surrounded the inside of the bomb. If drilled or sawed through, the bomb would explode.
After scanning the bomb with an x-ray, the FBI tried detonating a small shaped-charge on the top of the bomb that would destroy the circuitry and leave the main bomb charge untouched. The idea was to destroy the device circuitry before the electricity running inside of it could compete the circuit and detonate the bomb. However, the bomb creator actually had a few sticks of TNT placed throughout the inside of the bomb that went unnoticed in the x-ray scans to prevent exactly that from happening. When the FBI detonated the charge, they ended up setting off the main charge of the bomb and destroyed the entire building. | 48c392f1-4f84-43bd-af4d-c4ca0f629d56 |
c49g06 | How does sunblock prevent something as strong as the sun from burning my skin off? | We know by lots of testing and observation. Many materials are highly absorbent or reflective of certain wavelengths, so we found ones that are effective at deflecting UV rays and not awful for our skin. Except now we're finding out what we currently use might be worse for skin than previously believed and is definitely causing problems in the ocean so we're testing new options. | 2f50e6b3-4ee1-49c0-badc-abe5ae5274fa |
c49glp | Why are certain things found in nature like silver, copper, or wood considered to the antibacterial and what gives them this property? | It is called the oligodynamic effect when heavy metals kill bacteria by basically disrupting the biological processes going on in the cells - _URL_0_ | 890dfa2a-7333-4b50-87b4-74f4ab9e539e |
c4a02y | Why is hot spicy food more spicy than cold one? | Capsaicin is an oil, so heating it up makes it more fluid (runny) and let's it coat your mouth better. When cold, it doesn't mix with the water in your mouth as well. If you take a bit of cold butter, fresh out of the fridge, and put it in your mouth, it will have a different flavor than the same bit that has been warmed up (don't warm it up too much - you'll fry your tongue). | 04c3b3eb-f1bd-4fa0-bc04-8fd0d97a66db |
c4ap30 | What is intermittent fasting? I've been seeing posts describing they lost a ton of weight by doing it, can anyone explain? | Losing weight comes down mostly to calories and physical activity.
With Intermittent Fasting, you basically eat only during an 8 hours window each day.
Basically this will automatically restrict the amount of calories to can eat by limiting WHEN you eat, thus making you lose weight, unless somehow you're still over eating.
All weight loss diet work that way, by limiting by some way the amount of calories you eat. | 102176a6-5aeb-4ca8-9f97-82d629d93221 |
c4ary5 | Do butterflies regain any of the memories or anything else from when they were a caterpillar? | Surprisingly, yes!
This is surprising because when caterpillars change in the cocoon they release an enzyme that more or less turns their entire bodies into protein goop. It's less [Animorphs](_URL_0_) and more [The Thing](_URL_1_). Only a few cells survive this self-digestion intact, and they're *not* brain cells.
As /u/Monkey_with_a_knife mentioned, scientists have done tests where they give caterpillars a very mild electric shock that is associated with a particular stimulus, like a smell. It's just enough to cause pain without seriously inuring them. Later, if you present that same stimulus - that same smell - the caterpillars recoil, expecting to get shocked, and they avoid that stimulus.
The butterflies (and moths) that grow from those caterpillars recoil from the same stimuli, while the control group that was never shocked do not. This suggests that the butterflies somehow remember that the stimulus is associated with pain!
How they manage to do this is a mystery because, again, almost their entire bodies are digested in the cocoon down to loose proteins and carbs. Their brains don't survive the process - the butterflies leave the cocoon with brain new brains rebuilt from the DNA in the few non-brain cells left intact as the rest of the body dissolves. That itself is a bit of a mystery, too - the ability to not just regenerate, but completely rebuild their entire bodies! That's not *too* perplexing, though, because if you can build a body with a single cell and some energy in the egg the first time then there's no good reason you can't do it again. That's basically what cloning is, and we can do that with a lot of animals (albeit with special equipment and a whole lot of science).
But a clone doesn't retain the memories of the donor animal because memories, as far as we know, are encoded in the connections between nerve cells of the brain. If you destroy those connections (by destroying the cells) then you lose those memories and there's no way to get them back. Even if you build a new brain using the same DNA, the connections are made through experiences that cannot be replicated. In any case, that's how humans work. So how do caterpillar-turned-butterflies manage to do it? Nobody knows!
> Could be extended to any other form of life that goes through similar changes.
Generalizing this concept is probably not possible, although a lot of insects do go through radical transformations between larval stages and adult stages. I'm not a biologist and I'm not aware of any research into similar changes, and I don't know enough about how other species transform to comment on them. I know many insects, like cicadas, don't go through the same extreme transformations that caterpillars do: they don't completely dissolve their bodies, they just make some major changes to the bodies they start with. Their brains are left alone, more or less, so keeping their memories isn't that big of a deal. | 9c432abd-490f-4d7b-9fff-93cfd8242a75 |
c4ayq7 | Why do our muscles shake violently when you lift weights or something very heavy? | Your body uses charged atoms of some elements, also known as mineral ions or more popularly, electrolytes, to send the signal for your muscles to contract or relax, and your muscles use other mineral ions to actually contract and relax. Heavy use of the muscle can temporarilly use up the ions in those muscles cells, resulting in a loss of muscle control because there is no longer a sufficient supply of the ions to clearly signal and/or maintain steady contraction. Regular training helps reduce shaking as your body will adapt. When my muscles fatigue they don't shake, the weight just stops going up. Staying hydrated with enough electrolytes will also help, so drink your Brawndo. | 3c65dbd7-75a3-4e62-a81f-d2ddaf08d13e |
c4b01u | In 3D engines, why do spherical objects get split into polygons instead of being defined as spheres? | It's inherently easy and fast for a graphics card to draw 3D triangles; this is the basic unit of 3D graphics.
The math for spheres is much slower. | b781c80d-a8f0-4de1-9895-47163835ff55 |
c4b0gt | Why is it that during a storm, power always seems to flicker or go off. Why? | Well storms are associated with lightning, and high winds, both of which can cause power outages.
Trees being felled causing lines to short out, lines swinging violently enough can potentially short out, lighting strikes causing surges, blowing transformers, they're all things that would cause the power to flicker and die. | 52cb6211-d6ad-4c63-8c2b-d05e31f686df |
c4b2v3 | It seems most countries will keep adding debt indefinitely. How will this play out long term? | As long as the government can continue to service the debt it really isn't a problem.
Sovereign debt is not at all like the personal debt most people are familiar with. It isn't a loan from anyone, it's a country selling bonds and other financial instruments.
The US actually tends to make money from issuing debt, as US bonds are issued at rates lower than inflation most of the time. | ff5eac5b-5542-4f4b-817d-9759b71c0e3c |
c4b4g2 | Why are so many cities in the United States so close to state borders? | Because many state borders are set by rivers, and a river makes an excellent place to locate a city.
In the case of San Diego, the border was placed artificially after the Mexican-American War, specifically to include San Diego Bay in the winning (USA) side's territory. | c2e2005d-f15d-443b-bcd2-fa157e366fd5 |
c4bbp8 | I see people on my Snapchat opening shipped packages of weed and pills and stuff and was wondering how they even get away with it like how aren’t they caught? | Only a small percentage of mail is actually thoroughly searched when it comes into the country.
Shipping drugs is a *really* bad idea though, because the penalties for moving drugs across borders are severe. | c8688a6a-8cba-4d65-9391-a0fe139bfe11 |
c4bdpe | Apatosaurus and Brontosaurus. | Apatosaurus was discovered in 1877 and given its name.
Brontosaurus was discovered in 1879. Despite looking similar there were enough differences it was believed to be a different ~~species~~ creature and given a new name
In 1903 it was decided that these two fossils actually ~~belonged to the same species~~ were skeletons of the same type of animal and as a result should have the same name. Since Apatosaurus was named first it had priority for naming rights and the name was used "officially". However the name Brontosaurus entered popular culture and media and was more heavily known by the common man and as a result was still used even through the end of the 20th century.
In 2015 after re(re) examining the fossils it is now been determined that the fossils actually probably were in fact different enough to have seperate names, so now Brontosaurus is again being used in some parts of the scientific community. (There is still some disagreement among members of the scientific community about this point)
Edit: reworded and added punctuation for clarity | 95043a5a-691e-4e55-88b4-646d4069f566 |
c4brw7 | How do sigfigs work? | What is the MSRP of a 2019 Toyota Camry?
* If I said $20,000, that could mean it could cost $15,000.00 and I just rounded up. Or it could cost $24,999.99 and I rounded down.
* If I said $24,000, that could mean it cost between $23,500.00 and $24,499.99
This goes on until you reach the actual MSRP of the car, which is $24,095.00.
So just saying $20,000 sounds like an estimate. But what if the car costs exactly $20,000.00? Then you want to specify that all those digits are significant.
So think about a weighing machine. If it says you weigh 200 pounds, that means you could weigh 200.499999 pounds or 199.5 pounds. But the machine isn't sure so it says just 200 pounds. But if the machine is super accurate. Then it could say you weigh 200.01343 pounds. But it still wouldn't be able to detect if you weigh 200.0134349999 pounds or 200.013425 pounds.
So significant digits are a reflection of your level of certainty in a measurement. It's affected by both the accuracy and precision of the weighing machine. | c9f710f4-4372-40b2-85a8-90e6a1e32f0c |
c4c23q | How do mood rings work? | A mood ring is merely a fashionable liquid crystal thermometer. The color or change of color is related to the body temperature or change in body temperature in the wearer’s finger. | 0bc1558e-2924-42d8-8807-08215ed47caa |
c4c7nx | Why does wood not melt? | Wood oxidizes before it can melt. The heat causes the break down of various components of the wood into stuff like charcoal, carbon dioxide and water, which destroys the physical form of the wood well before it could melt. | d910679e-402d-4930-a600-6d3e0b918fce |
c4cjoj | How can one feel someone staring at them? | Its not. Numerous studies have been done on this and its shown people are about as accurate as flipping a coin. You just forget the times you were wrong because it doesn't matter. | e0fdafc4-cdf9-4c4a-8355-6522709527a3 |
c4cnl4 | why doesn’t a dogs hair fall out during chemotherapy? | Pet chemotherapy does not use the same high dosage as in people. Pets with aggressive cancer often only will live months to 1-2 years (with a few exceptions, notably low grade B-cell lymphoma that respond well to treatment), so the expectation is not usually a cure/remission, but to provide as long quality of life as possible, which would not be the case if we hammered them like they do in people. However, pets still do get side effects of chemo drugs affecting their rapidly dividing cells, but is usually limited to temporary bone marrow suppression and GI signs (vomiting, diarrhea).
People with cancer can live a long time if they reach remission, so they tend to be more aggressive, plus people understand the pro/con of the suffering and sickness of going through chemotherapy, making it worth it.
MOST dogs do very well with chemotherapy, side effects wise. | 33ef7aca-89d8-48f9-a4ab-cc561ee79835 |
c4d9tf | Why is every sunset different? | This is simply because of the natural variations in the density or types of particles in the air. | 392afe34-ace8-4292-8b45-947319a53a2d |
c4d9xp | Why are DDoS attacks still effective? Why isnt there an effective countermeasure? | DoS was first demonstrated 20 years ago. DDoS came about because there were relatively simple guards to raise the shields against DoS.
DDoS attacks while comparitively massive, can be held back, but it’s much harder and much, much more expensive.
Edit: never answered the “why”. Reason is that it it difficult to quickly differentiate the small amount of good traffic from all the bad stuff. | 36976d09-b8e5-4248-a2f9-6a8522529ecf |
c4dg5p | Why does the charge of one atom determine how many atoms there are of another element in a molecule? | The general idea is that a atom what a full outer electron shell. That i 2 electrons for the first shell and 8 for all other .
So look at the [Periodic table](_URL_0_) where the nobel gases on the far right column have full outer shells. If you move a step to the right you add a electron and a step to the left remove one. Covalent bond is sharing electrons and both atoms move a step to the right. There is also Ionic bonding where one atom lose a electron and another gain one.
So oxygen are two steps to the left so you need to add two electrons for a full shell and hydrogen is one step from helium so you need to add one. In covalent bond atoms share electron. So hydrogen what to share 1 electron and water what to share 2 electrons. So if two hydrogen atoms each share 1 electron with a oxygen atom each hydrogen atoms have 2 electrons and oxygen have 8 in the outer shell. The result is that all have a full shell and is happy.
& #x200B;
Carbon is 4 steps from a nobel gas so it like to share 4 electrons. So you can combine it with two oxygen that like to share 2 electron each and ger CO2 or with 4 hydrogen atoms and get CH4 (methane)
& #x200B;
A example of Ionic bonding is table salt NaCl. Na looses a electrons and jump one step to the left and have a full outer shell and Cl gain a atom and move a step to the right. | 890fe668-3bc0-4a53-8235-86ad1734f5be |
c4dgar | - How does the blood brain barrier work? Specifically what happens at the crossover? | In normal blood vessels, the wall of the vessel is made of cells, but it contains periodic holes that allow larger molecules like proteins and even entire cells to move through into the extracellular fluid. The BBB has much tighter seals between cells and doesn't possess these holes, so the only molecules that can move through are those small and polar-enough to do so by passive diffusion (moving straight through the cell membrane) and those that the BBB cells specifically want to move through - they have proteins called channels in their membranes that can pick up key molecules like glucose and pull them in. | c8ef7ea5-7890-4ae5-ab9f-d610f365b7ea |
c4e4kd | How do they measure the efficiency of a weather man? Are certain weather men "better" than the others just because they predicted the weather correctly more times? | There can be a big difference between the "weatherman" you see on TV and a *meteorologist* that is responsible for creating forecasts.
Generally speaking modern forecasts are very accurate, but can be easily misunderstood by people.
For instance if a forecast is 50% chance of rain, that doesn't necessarily mean every spot in the area has a 50/50 chance of rain. It means that in a percentage of the area the forecast covers there's a percentage chance of rain. So while there's almost no chance it will rain at your house it's almost definitely going to rain a few towns over. | 1794f6f7-1acb-4085-aa89-80b5cddf7c1f |
c4e4lm | Why VR games need way more power than other games? | > the googles moves could be a simple mouse move, right?
That isn't at all where the difficulty lies in computer games. Controlling the camera is dirt simple, the problem is figuring out the image to display for the camera position. Running the simulation of the game world, calculating how all the objects look from a given angle and lighting, is what takes up the bulk of the computational power.
VR games are more demanding than other games because in order to provide the 3D effect the game world must be "rendered" (the term used for the processing steps required to produce the image) from two slightly different perspectives for each eye. The field of view for each eye is also significantly greater than that of a monitor so there are more things to process, and the frame rate is usually necessarily higher to avoid causing nausea which again increases the computation load. | d73abd31-51af-4939-9642-d432d15d9512 |
c4ehzy | Why is speed of internet connection generally described in megabits/second whereas the size of a file is in megabytes/second? Is it purely for ISPs to make their offered connection seem faster than it actually is to the average internet user? | _URL_0_
> it is because the internet delivers those bytes of data as single bits at a time. And because those bits sometimes come out of order and from different server locations, it’s both more accurate and more intuitive to measure speed as a factor of the number of bits per second that an internet connection is capable of transmitting, not the total number of memory units, or bytes, it transmits. | 00e113b7-741e-414b-b0ea-564f4e37a70d |
c4euxn | How do animals avoid getting dehydrated when they hibernate? | Good question. Some species that hibernate aren‘t sleeping for months straight but sometimes wake up for a short time, there they are theoratically able to drink. But more important is, that hibarnating animals have reduced temperature, metabolism and so on. When you metabolize fat water is created, for many hibernating animals this is the main source of water. The usage of water created this way can be differently efficient, the best usage is observed in some species of kangaroo rats, though living in the desert they never have to drink as the water created by metabolizing food (they eat as far as I know nuts that contain lots of fat) is enough to survive. | 777926b4-c68a-40f4-9a81-cc9f84a18b68 |
c4fp32 | If Digestion Takes 6-8 Hours How Do People Experience Diarhea Symptoms in Hours? | Diarrhea happens precisely because digestion *hasn't* happened yet. Yes, normally it takes hours for food to make its way through your stomach and intestines to slowly absorb water and nutrients, but diarrhea is bypassing all that. Your gut has a ton of nerves, and when it senses something is amiss for any reason, it triggers your brain to send signals to get whatever is causing the situation out as quickly as possible. That means there's little to no absorption of water or nutrients. In fact, the intestines can actually add water or mucus to get things flowing even faster. | e48b238c-4d04-4020-9104-929df0090649 |
c4ftpt | Would there still be a sonic boom if what ever was traveling beyond the speed of sound made no noise? | The sound of a sonic boom comes solely from the object breaking through the sound barrier. A bullet does the same thing, which is why a silencer doesn’t actually silence the whole thing. The bullet is still going to break through the sound barrier, and make a cracking sound. Any object that accelerates through the speed of sound will create a boom sound.
Not scientific but pretty accurate I think | d11940dd-be54-4702-9277-64db3f5605de |
c4fxbq | What is the point of sister cities/twin cities? | They support each other to develop areas they have in common.
Similar to sister sports teams.
For example the English Premier League wanted to see US professional soccer more developed so they established sister teams.
In Colorado the Colorado Rapids sister team is the Arsenal Football Club. The Arsenal sponsored the Rapids and helped build them their own stadium which they never had before.
In industry we have a common thing called "benchmarking" where you go see how other people do things to improve your own. With sister cities you can see how they're doing something to improve your own processes. | 396eb3b7-8c6d-4d58-ac64-601d64d33571 |
c4gsdu | how do they measure the stats in food? | Before explaining how they measure, I'm going to explain measurements first. A calorie is a unit to measure energy. Most foods you see that are defined are actually in kilocalories (kcal), basically 1k calories. A single Kcal is the amount of energy needed to raise the temperature of 1 kilogram of water to 1 degree Celsius. Thus why most foods are measured in Kcal, even if they just say "Calories".
& #x200B;
There are many methods of measuring stuff like calories in foods. Originally, the food was placed in a sealed container surrounded by water--an apparatus known as a bomb calorimeter. The food was completely burned and the resulting rise in water temperature was measured.
& #x200B;
Now I can't really explain it better further on than an article that is linked [here](_URL_1_).
"
The Nutrition Labeling and Education Act of 1990 (NLEA) currently dictates what information is presented on food labels. The NLEA requires that the Calorie level placed on a packaged food be calculated from food components. According to the National Data Lab (NDL), most of the calorie values in the USDA and industry food tables are based on an indirect calorie estimation made using the so-called Atwater system. In this system, calories are not determined directly by burning the foods. Instead, the total caloric value is calculated by adding up the calories provided by the energy-containing nutrients: protein, carbohydrate, fat and alcohol. Because carbohydrates contain some fiber that is not digested and utilized by the body, the fiber component is usually subtracted from the total carbohydrate before calculating the calories.
The Atwater system uses the average values of 4 Kcal/g for protein, 4 Kcal/g for carbohydrate, and 9 Kcal/g for fat. Alcohol is calculated at 7 Kcal/g. (These numbers were originally determined by burning and then averaging.) Thus the label on an energy bar that contains 10 g of protein, 20 g of carbohydrate and 9 g of fat would read 201 kcals or Calories. A complete discussion of this subject and the calories contained in more than 6,000 foods may be found on the National Data Lab web site at _URL_2_. At this site you can also download the food database to a handheld computer. Another online tool that allows the user to total the calorie content of several foods is the Nutrition Analysis Tool at [_URL_0_](_URL_0_).
" | dd0d1fad-f1e1-45c8-94ae-14a8b747467f |
c4gvsa | the definition of gaslighting | I’m probably simplifying a bit too much, but essentially it’s when you manipulate someone by making them question their own reality. They might be certain of what they saw/heard/sensed/knew, but by gaslighting them, you’re confusing them to the point where they aren’t sure what’s real or true anymore. It often occurs over a long period of time so that the gaslighter can gradually sow seeds of confusion and eventually convince their victim that their perception of reality is false and inaccurate.
The term comes from an 1930s play called Gaslight, in which a man dims the gas lighting of his house; when his wife questions him about the change in lighting, he responds by saying stuff like “The lights didn’t dim” or “You must be imagining it”, and eventually she comes to believe that he’s right and she is just imagining it. This is a pretty good example of the term. | a1f62ccc-4966-481f-9cb6-cb0791d7ee3b |
c4gw8u | Why would game companies like Xbox or others discontinue things like guitar hero and connect? | Because they lost popularity so it wasn't cost effective to continue supporting/making new versions of it. They're in the business to make money. | e3e92d33-bb00-4598-bcd3-68381ee357f3 |
c4h3l9 | If the events depicted in the Netflix show Narcos are to be believed, why did the DEA fund a drug cartel? | CIA has a totally different level of friendships and relationships in the world that most people will never understand.
Think about it like this- CIA could care less about illegal things. All they care about is governments that are friendly to (USA) them. In the CIA’s role of supporting that government or the rebels that are going to overthrow that government they will do what ever is necessary to help. Need to sell drugs to finance a war-done. Need to transport guns and weapons to get the to the front lines-done. Need to hack the web, build a bridge, kill a presidential candidate- done,done and done. With data they have collected, they gamble on the winners. Most of the time the win, but all the times they lose and something gets royally fucked up- you here about it. Drug addicts were just a byproduct of the game... | 102c4279-6a76-4797-bc05-dd1ea1ce98cd |
c4hu7m | Ok. I'm old. What does (tag) mean in insta and twitter. | r/explainlikeim55
If you tag a person who is in a photo, or associated with a photo, then it will show up in their profile or at least list them under the photo.
Edited and put relevant info first. | f0a5b214-074e-401a-b958-fd83ebce1d19 |
c4icyp | Why do our hands move when we walk/run? | The answer is very simple. For balance. Go try to run full speed while keeping your arms/hands perfectly still at your sides and tell me how unstable you feel. Notice how when your left leg goes back your left arm goes forward? It’s to help keep your center of gravity from being shifted so much while running/walking.
Many people are saying that it “conserves energy” however that makes no logical sense. It requires energy to move your arms. | 90b46626-70c5-4162-846f-91f9870f3e75 |
c4ihfp | What is the sun's spectrum and how does it work? | Heated matter emits radiation. Most commonly as infrared radiation which we can't see but can feel on our skin. When the heat exceeds a certain value, it starts glowing red. Keep heating up and it becomes yellow, then white, which means that all visible wavelengths are emitted - like a very hot piece of iron. Knowing this, we can attribute the heat to the colour of the light: 5500 degrees Kelvin is daylight "colored" (this light colour temperature is printed on light bulb boxes).
A perfectly black body would emit all wavelengths that come from this temperature. But atoms and molecules absorb very specific wavelengths. So while we know that a star of a certain temperature would emit a certain spectrum of so called blackbody radiation (which wouldn't absorb any specific wavelength), we can observe that certain wavelengths are missing from the expected spectrum.
From the missing lines in the observed spectrum, we can deduce the presence of certain elements in a stars surface, which tells us a lot about that star. | 99dc867e-4014-421b-8b31-6d358cdf9d06 |
c4iii4 | In the US, when shipping commercially from the mainland to a U.S. territory (e.g. Guam, Puerto Rico, American Samoa), it's treated as if it is heading to a foreign country. Why? | FedEX and UPS treat shipments to U.S. territories as international because it's expensive to ship and they can collect more money that way. It's their internal system. They are not at all required to do any of that, and the USPS does not. Commercial shipments to Puerto Rico or the U.S. Virgin Islands from the states are not exports, and there are no tariffs, customs, or duties because they're part of the U.S. Legally, the only difference in shipping there as opposed to another state is that you need an Electronic Export Information (EEI) filing for merchandise worth over $2,500 because Puerto Rico has its own tax system and collects taxes on those goods. Fedex and UPS could absolutely treat shipments to U.S. territories the same way as the USPS. They just choose not to because they know they're a lot faster than USPS and people will pay more for "international" shipping that's faster than the USPS. | b28f2af5-e42c-4482-89ea-f5bb84a9d81a |
c4imqf | How is it possible that ALL world economies are “in debt” simultaneously, and to whom are they indebted? | Short answer? Their own people.
Basically, national debt works a bit differently to personal debt, but the short of it is that governments can issue IOUs to whomever will take them, in the form of bonds. These can be issued to individuals, financial institutions, other countries, and sometimes itself (for instance, the US borrows money from and issues bonds to its Social Security Trust Fund). As long as a country grows enough that it can pay the interest on these bonds, they can maintain them indefinitely.
To more specifically answer the question of who owns bonds, to use the US as an example, most of it is held by US citizens and companies, and some of it is held by foreign countries. US bonds are possibly the safest investment for anyone, due to the US having never defaulted on its debt, its economy continuing to grow, and its secure currency. Basically anyone who buys US government debt gets their money back. | a6883e25-dd0b-4f73-945d-c423529b7911 |
c4inl3 | Why does it take such a long loop and tremendous energy to accelerate really, really small particles at, say, the LHC? | There are a couple competing accelerator designs: stright-line, and circular.
The straight-line ones are obviously simpler, and easier to operate, but they can only speed up particles *once*, in a single pass through the accelerator. So the energies you can reach are limited by how quickly you can accelerate the particles.
The circular accelerators avoid this problem by using magnets to bend the particle's paths into a loop. That way, you can give them another "kick" every time they go around. This does however create 2 new problems:
1. The faster the particles are going, the more force it takes to make them bend. We're limited by how strong magnets we can make, so you have to either make the circle bigger to make it curve more gradually, or stay at low enough energies that your magnets can handle it.
2. Bending the particle's paths actually makes them lose energy. There isn't a good analogy for this, but whenever you accelerate a charged particle it radiates energy away as light (accelerate meaning any change to its motion, speeding up, slowing down, or changing direction). By bending the particle's paths, you essentially subject them to a sort of "drag" that makes them slow down over time. So yes, you can give them a kick every lap around the loop, but they also loose speed during the trip. The end result is like pedaling a bike; eventually you are pedaling as hard as you can just to maintain a constant speed, not managing to go any faster due to the drag forces trying to slow you down.
So, if you tried to make a tiny tabletop accelerator it could totally work! It would just be limited to low energies. That's how the field started out after all, nobody would just toss you a few billion dollars if you've never tested the design. We got there gradually building bigger and bigger ones as needed, and as the technology matured. | a485adf8-e430-44a0-a2dd-7dd042ca81d9 |
c4jyvs | How and why dust is formed | There’s no “why”, dust is mostly made up of dead skin cells that flake off your skin constantly as they’re being renewed. Because they are dry and dead and very light, they float around until they settle or until enough of them stick together to become heavy enough to drop. If you thoroughly clean a room, let the dust settle and clean it again, you’ll see that almost no new dust will appear if you stay out of it. | d2ce29da-07af-4d9c-a241-6762786a8cd1 |
c4jzfl | - Why does skin repair on your face when you get a scab, but not when you get acne? | Oh, it’s *trying* to heal. But acne isn’t one owie a year, it scabs over and it’s done... acne is an ongoing process where every goddamn time an individual wound starts healing, something else causes yet another wound (often in the same place). Some pores do make it to the scab stage and return to normal eventually— but others are stuck in a permanent cycle of partial healing and yet more destruction. | cb27d8d8-0496-4d07-8225-88594c411f02 |
c4jzm0 | How/Why is the universe expanding and will it ever stop? Any speculations as to what lies in the unobservable universe? | Expansion seems to be an inherent property of the "stuff" that is space itself. That is, there is some energy in space (or rather space has this energy as part of itself), and that energy pushes space apart (expansion) leading to the creation of new space as the existing space expands. We call this "dark energy" and no one knows what it is or where it comes from (other than it almost certainly exists).
As to whether it will ever stop - we don't know. There was a time when expansion happened much much faster (the very early universe during the time of [inflation](_URL_0_), and we know it slowed way down after that, and has been accelerating in the (cosmologically) recent past through to the present day. We expect it to continue to accelerate for some time, and possibly forever, but it may not. We just don't know, although theories abound.
As far as what lies beyond the observable universe, most cosmologists and physicists think it's just more of the same as what we can observe. So far, year in and year out, as our observable universe grows at the speed of light in all directions, we're just seeing more and more of the same stuff. | 1d232831-a0e5-469b-a94d-1f7617dab9c3 |
c4k48s | Why/How did the early primates progress to become humans? Will there ever be any new beings as intelligent as humans originating from different species? | Early primates had problems, and solved them with their brains. There's a few other animals that are also doing that, but they don't have all the same advantages humans did. There's also different kinds of intelligence.
* Octopi are very intelligent and can hold onto complex objects very well, but they live underwater (no good tool materials), don't form large groups (minimal sharing of information), and have very short lifespans (smaller chance to learn complicated tricks in one lifetime).
* Dolphins are intelligent, social, and have no hands, and tool materials are limited by being aquatic. Similar problem to the Octopi.
* Crows/Ravens can use and make tools, and use teamwork or environmental quirks to their advantage, but they are small, fragile, and have to use their mouths or feet to hold things. This means they can't hold more than one thing at a time very easily, which means they can't make specialized tools in advance and carry them everywhere.
* Elephants are social, strong, and have one thing that can hold tools, but they don't live in a lot of places, and they're better at cultural knowledge (death rituals, long complicated relationships, remembering people and places they haven't seen in years, etc) than technological/tool knowledge. They also have very very long gestation times, so generations come very slowly, and are very huge, so it takes a lot of food to feed even a small group of elephants. They won't form giant cities very easily.
* Dogs and Cats are good at human social interaction, and some of them manipulate their owners, or understand using things like doors. Sometimes dogs form large, feral social groups, which can feed themselves by hunting or living off of human trash. They don't have enough fine dexterity ("hand"-eye coordination) to manipulate complicated tools, and some are much, much, much less smart than others.
I think there's nothing specific stopping other animals from getting humanlike intelligence -- but there's a lot of things that make it hard for any given one of them to pass down tools and information, learn agriculture, build towns, and gradually start gaining technology.
Some advantages humans had and used to get where we are:
* We hunt in groups, meaning that humans who communicate better are more likely to eat, survive, and multiply. We also got very, very, very good at communication -- a lot more than the neanderthals, which didn't have throat anatomy that lets modern humans speak.
* We are bipedal with hands, which lets us carry two things while walking, easily. Our hands can apply enough force to break something in a very well controlled manner, which makes weapons and general tool-creation a lot easier.
* We have both strong nomadic tendencies (making it easy for us to spread), and strong territorial tendencies (making it easy for us to settle down somewhere, and defend a location from outsiders, encouraging those outsiders to be more nomadic).
* Since the thing we hold stuff with isn't attached to our feet or our face, we can hold dangerous or awkward things like flaming torches, or containers of molten metal.
...there's probably other things, but this is what comes to mind right now. | af815dc8-57a1-4ac3-93d7-e8603c8fe298 |
c4k80i | Why do railway tracks have stones around? | The stones are called Track ballast.
They are there so water can drain away from the track and doesn't cover it.
They are also hard for plants to grow on, so you don't have to clear bushes from them as often. | 590c6aea-405c-4d78-a657-f8e93751deee |
c4k93s | How do divers manage not to sink even though they carry a heavy iron tank? | Divers wear a backpack ([BCD](_URL_0_)) which the tank attaches to. The BCD contains an internal baloon that can be inflated or deflated to control the diver's buoyancy.
The human body's natural buoyancy, along with the added buoyancy from the wetsuit, actually require divers to wear belts strapped with lead weights.
Source: am a scuba diver
EDIT: Also, in my experience, most SCUBA tanks are made of aluminum, not iron. | 9c3fbe60-a8b5-46b0-9e40-049657f58f7d |
c4kpmz | how does the US post office know I’m using a real stamp and not just a fake stamp? | In reality, stamps are too cheal for post offices to really care. But there are measures in plase. For example, stamps are printed on a material that ismt just paper, so a low quality counterfit might get caught. Also, many stamps are printed with a substance that reacts to a sertant spectrum of light. In the end however, its not a good idea to counterfit stamps because it is a federal crime. | d59fbc47-956c-499c-a32a-38f79ef04b00 |
c4ku11 | Sampling Rate and Bit Depth for Audio | Think about a video. It's really just a bunch of still images being shown to you in rapid succession. The faster those images are shown, the smoother the resulting video. In videos, it's called framerate.
In digital audio, the data is presented as a series of "sounds" that are recorded or presented in rapid succession. The faster the rate, the smoother the sound.
& #x200B;
Thinking back to the video analogy, the more pixels you have in those still images, the more precisely you can create an image. In videos, it's called resolution.
In digital audio, the bit depth represents how many bits (1's and 0's) are used to represent a particular "sound". The more bits, the more precisely you can create the sound. | 4c0a55b9-cfd1-48aa-abb1-1d5037dfeb96 |
c4l6wh | what is autism and how do people with autism differ from people without autism? | Autism isn't really one thing. Like many other personality traits, it exists on a scale. At the very far end is something we call low-functioning autism. People with low functioning autism have serious cognitive impairments. This is usually associated with low IQ, and people with low functioning autism will require a huge degree of assistance all throughout their life. They may never learn to speak. Fortunately, low functioning autism is pretty rare. The vast majority of autistic people are 'medium-functioning' ie possessing significant and notable behaviours, but not to the point where it fully impairs their ability to function, or 'high-functioning', which is also known as Asperger's.
Most people with high functioning autism you simply won't notice have it unless you spend a lot of time with them and form a pretty intimate relationship. Every person with high functioning autism is slightly different, and manifest different symptoms, but common symptoms are as follows:
Late development, both socially and mentally, often 1 or 2 years behind peers in certain things like language and cognitive empathy (understanding not just that someone is having an emotion, but what emotion it is and why it's happening).
Sensory overload - If their brains are having to process too much sensory information, like sounds, smells and to a lesser extent sights all at once, that can be incredibly painful and in worse cases could lead to panic attacks or meltdown. Often, autistic people are unable to select what they listen to, too, so for example they can't simply choose to ignore a car alarm and will be physically incapable of thinking complex thoughts until the alarm is shut off.
Hypo-sensitivity - some autistic people are actually *less* sensitive to noise, and will seek additional sensations. This occurs in the form of 'stimming', which is a behaviour you might have noticed before. The form this takes varies a lot, but a common one especially in children is "flapping", where they'll just kinda waggle their hands and arms violently. In adults, restless leg syndrome is a common one, and rocking back and forth is common across many ages, to varying degrees. The stimmings that people use is chosen more by social convention than by anything else - it wouldn't really do for an adult to be making big, noticeable gestures in a public place, especially at work. Stimming helps to reduce stress and feel like the person is in control.
Hyper and hypo-sensitivity can both exist at the same time, for different senses.
Dampened emotions - many autistic people don't experience the normal highs and lows of emotions, so while they don't get especially happy they also don't get especially sad. Anger and frustration tends to be an outlier here, at least in the moment, although many autistic people aren't very good at bearing grudges.
Autistic people are often quite physically clumsy, although that's not typically required for diagnosis.
The big one that everyone probably knows is that autistic people aren't as good at social interaction as neurotypicals. This is usually because they aren't as good at picking up social cues, especially non-verbal ones. Autistic people sometimes use language in quite unusual ways too, often speaking more like characters in books, with more concise sentences, less repetition and more diverse vocabulary. They often express pedantic and idiosyncratic speech, where they'll become formal or use unusual sentence structure even in casual situations. They may invent metaphors that mean something only to themselves, and often struggle with non-literal speech, interpreting many common language techniques like over and under-statement as literal.
Many autistic people exhibit tangential and circumstantial speech, where rather than focusing on the topic at hand, they'll wander off and end up talking about completely irrelevant things, often extrapolating minor remarks into entire conversations. Autistic people commonly speak monotonously, with only a small range of pitch, and will often go on monologues about things the other people aren't remotely interested in without noticing. They often make comments without explaining the context behind them, which can cause problems when they end up saying something offensive that wouldn't have been if they'd explained the situation first, and some autistic people struggle to control what they say, simply saying things that come to mind before they've realised they shouldn't do that.
Autistic people usually have quite unusual hobbies - often ones that include repetitive motions and thoughts. They can become intensely focused on these things, to the point where being interrupted is an absolutely huge deal. They can also struggle with spontaneous, unplanned changes in things. For example, if they planned to go out at 5:30, they might become irrationally panicked if they ended up going out later *or earlier* than then. Autistic people often engage in compulsive, almost subconscious behaviours, like lining objects up into rigid patterns.
Autistic people are often very sensitive to small details, noticing tiny changes in images that most people wouldn't notice, and also becoming enthralled by minor irregularities in mundane things, like a small dent in a wall or an irregular pattern in tiles in a bathroom.
Contrary to popular belief, autistic people *aren't* smarter than regular people, they just think in different ways that predisposes them to be better in scientific fields where attention to detail and more logic-driven thought processes are valuable.
We don't really know what autism is though, we only know how it manifests. It's thought that it's a combination of genes and environment, and definitely has nothing to do with vaccines. | 4db9d0c3-8430-4896-98d1-50f1ea6289cb |
c4ldpv | How is steam so effective at removing wrinkles on your clothes when ironing? | When fibers become moist, they gain flexibility. As they lose moisture, they lose flexibility. Steam is the most efficient way of moisturising fibers. As you moisturise the fibers, then you straighten them out, then you dry the fibers, you give them a new shape. | 28c2c0b7-4618-436a-8c97-a85ba45eb5cd |
c4lgz9 | How do people make money by predicting when stocks are going to drop? How can you benefit from an expected drop if you don’t have any shares beforehand? | You borrow shares from someone else by the promise of returning them within a given timeframe. You then sell your borrowed shares at the current value and rebuy shares from the same stock after the, hopefully, predicted drop has occured for a cheaper price which you then proceed to refund to the original shareholder. You keep the difference. Aka. "Shorting" | 459b62cc-1e81-46ac-a8f9-b76dd50dd932 |
c4lv1j | What is CPR doing to revive someone? | Nothing. Not a single, solitary thing.
CPR is a misnomer; there is no rescuscitative component to it.
The one and only thing CPR is meant to do is serve as a stopgap way to manually circulate blood and maintain brain function until someone else can get there and start more advanced procedures. | ae936be9-0015-4d3a-9338-6aaa51516f96 |
c4mvaw | what’s an offshore account? | Offshore means not-in-the-country, or international. Generally, however, an offshore bank account is an account in a country that allows you to keep your banking confidential and protected from your own government. Usually as a means to keep the money secret so as not to pay taxes in your country or for hiding dirty money. | 2549e05b-691b-41c6-a4c0-337106aebec8 |
c4n0xr | How do anti-tank weapons kill tank crews after penetrating armor? | Anti-armor explosives have shaped charges that use explosives to force a concave piece of metal (like copper) into a molten jet of metal that pierces the armor. Once through, it is still molten and moving supersonically, introducing hot metal, plasma and a concussive, expanding shockwave to the interior. Soft, squishy humans react poorly to those sorts of things. As well, some anti-armor rounds cause large scabs of interior metal to fly around at high rates of speed. | cbb1486d-61f6-42fe-a9cb-c1f840f54ade |
c4n8uv | If the vacuum of space is a thermal insulator, how does the ISS dissipate heat? | Vacuum insulates against *conduction*. It does not insulate against *radiation*; in fact radiant heat travels better through vacuum than through anything else. | 22c8dcbb-6dd3-4443-b135-2b405487edcb |
c4n929 | Do zebras have black skin with white stripes, or white skin with black stripes, or neither? Explain please | Zebras are black with white stripes, although the striping is so ingrained that the distinction is essentially arbitrary. We only know they're black because of embryological studies that proved black was their "default" and the white parts (where pigmentation is inhibited) are determined later on. | 57e4d137-788b-4340-85e7-8a88d5b93b09 |
c4nbxw | Why womwn after menopause tend to gain quite a bit of weight,even if they change nothing about their diet? | Because they have started to produce less estrogen. Estrogen is itself a steroid hormone, and it readily gets converted into other steroid hormones like testosterone, so high estrogen levels are generally associated with higher metabolic rates. When the estrogen level dramatically drops for menopause, the overall metabolic rate tends to drop with it, making it harder to keep off weight. | 5d3eb42a-9dfe-4f77-824a-607b85a0230e |
c4ncky | How do they come up with names for new medical conditions? | Many are named after the doctor who first documented it or first documented in depth like doctor John Langdon Down whose work lead to the Down Syndrome being named after him.
Others syndromes and diseases get named after patients who have them.
Some are merely known for what they do like AIDS.
In the past diseases where often named based on where they were thought to be from, but since every country had their own idea where the diseases originated (other than not here) that led to everyone having their own name and wasn't really helpful. | 83ef3041-14a6-4d8c-8cff-ac4b087f2a41 |
c4nm1q | What determines the change between different currencies? | It works essentially the same way as the stock market. The price they are advertising is the price that they are currently able to get, but there is constant negotiation up and down on the price, and anyone given person might be able to get a slightly better price than other people at any given moment. | a20d265c-e39e-48b2-a36d-b4539abfb15a |
c4nww5 | Why do the bags under your eyes get more pronounced with lack of sleep? | The bags under your eyes are typically caused by liquid building up under the skin - that's where the bruise-like colour comes from, and why they're puffy. The technical term is "periorbital (next to the eye) puffiness".
This liquid buildup is usually due to your body not processing materials as quickly as it usually does. When you're tired or under stress, for example when you're short on sleep, your metabolism slows down to save energy, and a lot of biological processing slows down with it. This means blood and lymph don't drain as well as they should, because they carry more toxins and large molecules, and because it's a non-vital process that your body slows down when it's trying to save energy. So fluid builds up under the eyes, and bags appear.
Another reason for this is that muscle tone is reduced when you're tired - that's why lack of sleep also leads to heavy-feeling limbs and weakness, from quite early on. This means that any existing swelling or fluid buildup is likely to get worse, as it's not being redistributed by tensing the muscles around your eyes.
Mostly, though, it's the fluid build-up thing. | c0490c84-018e-4818-818c-534cda82aaed |
c4o9th | Why do adults have very thick bones but apparently bone growth stops around 18? | Bones never stop growing thicker. The only thing that stops around age 18 is the lengthening of bones.
In your long bones, like the ones in your arms and legs, there are regions near the end called ephysial plates. These are areas where new bone is being laid down, lengthening the bone. But those stop working around age 18.
But you're also constantly laying new bone down along the edges from the membrane that surrounds the bone, and within the bone itself it is constantly remodeling itself, and this process never stops. | 4c23ffce-b657-47a3-83b9-dfdb4f9b8f26 |
c4orj9 | How Do Pain Medications Know Where To Go? | AFAIK every pain is registered in your brain, so all the pain killers need to go to the brain. They block the "pain calls" | dff514ad-e670-46f6-ac33-240ebf813010 |
c4p134 | How does music of dead/retired musicians get remastered? | If you have individual vocal and instrument audio tracks from the original recording, you can process them separately with more modern technology.
Suppose one of the tracks was noisy or had limited sound quality due to the technology at the time. You could replace the track or filter out the noise. You could make it more on-tune with auto-tuning technology. Mix all these processed tracks back and it will be remastered.
It gets more complicated if you don't have the individual tracks. There are some ways of isolating the human vocal tones away from the instruments but depending on the type of music, this may be hard to separate.
Even more future technology will allow you to synthesize a person's voice given enough samples. This is still in progress but it will open up a whole lot of issues with ownership of the voice and its use in deep fakes (forged audio or videos). | b5fdb6f5-3bf7-414f-bdb4-39a6b15236c6 |
c4p55k | where do protons and electrons come from? | Primitive particles created out of the energy released at the Big Bang. By about one second after that event, it's believed most of the protons we have today were already formed. | e35d093b-eb73-4fb6-92ed-2ae6993470ed |
c4p5eq | What are functions and methods, and what are the differences between them? | Do you know what objects are? If not, this isn't going to make much sense & you need to go pick up some background info.
A function is a piece of code that you can pass data into & get get data out of - just like mathematical functions, except that they can have side-effects.
A method is a function that's bound to a particular object or class and is implicitly given a reference to the object/class as an argument. | 85e3b667-3926-4e11-b1da-0c3b197ea8cb |
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