This is amazing thank you so much! This is more helpful than you could know 😊 I tried reading science pages on Google but they always use unnecessarily large words that my dyslexic brain doesn’t understand.

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Thanks for pointing out that commenter's moving goalposts.

Prisms work by refraction.

Light travels at a fixed speed in a vacuum. But within a material, light travels more slowly. You can think of this as something like a wave traveling through a harbor, jostling boats as it goes, and being slowed by the fact that it is transmitted by the way the jostling of one boat reproduces the wave on the other side. The difference in speed is called the refractive index of the material. Air slows light by only about 3 parts in 10,000, but water slows light by about 1/4, glass by about 1/3, and diamond by about 60%.*

When you move a wave, including light, into a region where it travels more slowly, the wave bends. This is refraction, and it's simply what happens when you slow down one side of a wave; there's nothing magical about it. So when light moves from one medium (=material) to another, it bends.

Since the refractive index of some materials depends a bit on the wavelength (=color) of the light, the different colors of light bend by different amounts. That results the different colors (or more properly, different wavelengths of light) in the incoming beam splitting apart and traveling at slightly different angles.

With that model in mind, we can answer your questions:

> If you shine a coloured light what would happen?

In a colored light, not every incoming wavelength would have the same brightness. So you'd still split the beam into its component wavelengths, but some would be brighter than others. Since many possible mixes of wavelengths can produce the same colors, you could actually shine two different (say) yellow lights into a prism and see two different resulting spectrums.

> Why does it need to have an angle if you can use cuboid ones?

Refraction happens even without an angle, but when the light exits the other side of an object at the same angle (as it does if the would-be prism has two parallel sides), the same refraction happens in reverse. This puts the rays back in parallel. Since the rays didn't separate much in their brief travel through the material, all this results in is a very slight violet tinge on one side of the beam and a very slight red tinge on the other, and even that is a result of the fact that the beam has some non-zero width.

If the sides aren't parallel, though, the light doesn't hit the other side at the same angle. This causes the rays to further disperse (more sharply this time, because this time they weren't even striking at the same angle in addition to the wavelength-dependence of the refractive index), which is what produces the widely spaced bands of color you associate with a prism.

> Do different shapes give different affects?

The overall shape isn't important, just the angle at which the light enters and exits.

* You might wonder about the full physics of exactly what's happening here. There are a few ways to think about it.

One is that, in effect, the light is diffracting around all the billions of billions of billions of particles in the material. That diffraction results in an interference pattern, and it turns out that the interference is only constructive at the angle the light apparently "travels" and destructive everywhere else. Since interference patterns are in general wavelength-dependent, it's not too surprising that the refractive index is wavelength-dependent with this idea in mind.

Another is to think of the light as effectively setting up a resonance in the material, with the photons forcing the molecules in the material to vibrate along with the light's frequency. That vibration, which is a vibration in charged particles, produces a vibration in the electromagnetic field - i.e., the original light - but traveling more slowly and with its phase shifted.

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There's no way you saw me

> Cubes also have angles.

An object with parallel sides won't act as a prism, because it puts the rays back in parallel as they exit.

Someone in the comments explained it really well, but plants need nitrogen and phosphorus to grow. Usually those are in limited quantities, so growth is limited by the amount available. Fertilizer is designed to provide an abundance of nitrogen and phosphorus to plants, so if those high quantities end up in the water, algae growth isn’t limited and can grow more rapidly.

We have a "green detecting" cell in our eyes. This cell does not see any green, therefore our brain knows it's on the "other side" of the spectrum from green. We therefore have purple, a reddish-bluish color which cannot be represented by just one frequency.

Does it affect yours eyes ?

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Low Carbon Steel or Mild Steel. It have between 0.05 and 0.25% of carbon. It have lower strength than other form of steel, but it's also more ductile which mean it's easier to machine or work with. This make that steel ideal for structure like building, bridge, etc. Because even if they have a lower strength, they are easy to shape into different shapes. The fact that it's ductile make is also safer in building, basically the building will bend which give notice that something is weird and it won't just collapse on the people right away.

High Carbon Steel have between 0.61 and 1.5% carbon. This type of steel is very strong, very hard and harder to machine or form into shape. This make it ideal for item that will have to endure a lot of wear like tools.

Medium Carbon Steel have between 0.26 and 0.6% carbon. It's an happy medium between lower and high carbon steel. Things like gears, bolts, automotive components, etc are usually made of that steel. They are parts that will suffer some regular wear so mild steel would be too damage, but it doesn't suffer enough wear to justify the higher cost and difficulty of working with high carbon steel.

Cast Iron have between 1.7 and 3% carbon. It's much harder than Steel, but also very brittle. Mild Steel usually around 130HB of hardness, medium carbon steel is around 200HB, but cast iron is closer to 400HB.

Stainless Steel have a high content of chromium (between 10 and 30% depending the type), but it can have different level of carbon up to 1.2%. That said, just like normal steel, the most used type of stainless steel will have lower amount of carbon than that.

Alloy steel well those can be anything, different type of metal added to the steel (usually in small percentage) will have different effect. Molybdenum increase the toughness so some cutting tools, turbine blade, rocket motors' parts, etc. Tungsten increase the melting point. Boron increase the hardness. Bismuth make it easier to machine. And many more.

Wrought Iron have a very low carbon, less than 0.08%. As you can see from 0.05-0.08% it could be both wrought iron or low carbon steel. That's because wrought iron isn't define by the carbon content, but by how it was produced. See in the past we were not able to measure the amount of carbon, so we didn't categorized iron by their content like we do today, but rather by the way we produced it. Wrought Iron (low carbon) was made from iron ore in a bloomery, but it take a long time. Pig Iron (high carbon) was produce by using a blast furnace and it was faster to produce than Wrought Iron. What you could do after is take your molten pig iron and add stuff like coke, limestone, you can also burn the impurity and you end up with cast iron. Or you can take your pig iron into a finery forge or puddling furnace to make wrought iron, this was faster than the earlier bloomery. Other things we used to do was beat the hell out of cast iron to slowly remove the carbon out of it or mix cast iron with wrought iron to reach a better level of carbon. Both medium were relatively expensive at the time.

It's only later when we develop steel metallurgy that steel took over the traditional iron, and now we categorize steel by their content, rather than the method of production. But now since both way of categorizing exist, it can be a bit confusing.

When light slows down on an angled surface, it is bent. The more it slows, the more it is bent.

Light of different frequencies moves through glass at different speeds. This means that different colors bend different amounts. If multiple colors are lumped together, then each will bend a different amount, and so they will separate.

Cubes also have angles.

Different shapes and glasses can have different effects. The right shaped "prism" can be a magnifying lens. The photographic effect called "chromatic aberration" comes from the camera lens acting as a prism.

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This is true and a product of me oversimplifying.

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> However, even if they sell 10 seconds after that report goes public, THAT is fine because now the information is public.

I have a minor nitpick: at my company (and I think this is pretty common if not the law) the trade window doesn't open until several business days after the report goes public. That gives the market plenty of time to digest the information, trade on it, trade on others' trades, etc.

Yeah, I get those a lot on mobile.

Antibodies can also be transmitted to the baby through breastmilk, especially the early breastmilk called colostrum.

We can write math without any "order of operations". It is just inner functions (or rather relations) all the way down.

It gets really ugly looking really fast. So you never do it unless you have to prove something involving order of operations.

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This is very hard to answer definitively because what information they track is secret. If they explained their algorithm for human detection, people would update their bots to look more like humans.

What we can glean from some discussions about it and some common sense is that a lot more is going on than just whether you click the right images or the check box. Sometimes you don't even have to click trains or crosswalks or non-civilian targets.

The code already knows a lot about the person you claim to be and the things you usually do. It's already made some guesses based on your IP, the information your browser gives up, the time of day, and what site you're trying to visit. All of that alone is probably enough to verify that you are the right person, but it's not enough to verify you aren't running a program working on your behalf to do things in a fashion the website owner doesn't want.

So it also tracks how your mouse moves to the checkbox when it's time to click. Bots can sometimes move in a very "not natural" way so it looks at the mouse movements to decide if a bot's involved. Maybe you did touch input: that still gives a lot of data about the "tap gesture" like the size of the tap, how long the finger stayed down, the shape of the tap, etc. Bots don't simulate that very well, or when they have to generate multiple taps they tend to create recognizable patterns.

All of that is real squirrely. Sometimes you have to go through multiple rounds of "click the picture". That's probably when something about your input looks "not human enough" so the system wants to see more. Eventually you make it confident enough it's dealing with a human it lets you through.

(Let us also not forget Google sells products based on its image recognition AIs: a side goal of this program has always been presenting images their AI has trouble classifying to humans who can help train it to be better.)

The thing is this is kind of like locks on a house's front door. A person who's spent a few months practicing with lockpicks can get inside silently in less than 30 seconds. But even among criminals the number of people who invest that much is a small percentage, and the people who do generally look for bigger scores than the average household contains. So a simple deadbolt is enough to keep out a large number of criminals, but for the ones not deterred it means they tend to try noisier or more violent forms of entry, which is less likely to go undetected.

That's what bot detection does. Many bots just aren't sophisticated enough to pass the gate. The ones that are get slowed down by dealing with the process. Part of the goal of regulating bots is making sure bot traffic doesn't overwhelm sites and APIs, and slowing down bots is one way to accomplish it.

So no, it's not a perfect shield against bots and can sometimes even reject legitimate humans. But the purpose is to make it harder to use bots and to make the bots that work less efficient. It's good at doing that.