Mand125

Mand125 t1_jadrlwp wrote

Reply to [eli5] How do you actually invent nuclear bombs. And how do you keep them under control? by Linzold

Well, the point of the bomb part is you not keeping them under control.

How we did it the first time was decades of research from the world’s best scientists, starting with the basics of nuclear physics and how the different particles would interact. On top of that knowledge was a ton of engineering about how to manufacture the material components needed, including building an entire chemical processing plant at Oak Ridge, TN. Then it was experiments on the different shapes and components, and how to get them to work together.

Ultimately, the process is to take the fissile material and drastically compress it, turning it from merely dangerously radioactive to explosively radioactive.

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Mand125 t1_jadjab2 wrote

Reply to Eli5 why do we perceive red+blue as purple? by YYM7

You have three types of cells in your eye that see color, called cones because they’re cone-shaped.

Each of the three has a color it’s best at detecting, and we name them based on that. One for red, one for green, one for blue.

But, it’s not that they see one color and that’s it. Any color you could pick will hit all three, and the ratio between the three signals they send to your brain is what turns into a color perception. Also, the color they’re best at isn’t a narrow sliver, it’s a big hump of the spectrum that falls off to either side of the middle color.

Yellow activates a bit of the red cone and a bit of the green cone, but not as much for either as a red color or green color would have.

Same for colors near blue, a nice teal will activate the blue cone and a bit of the green cone.

But for violet, that’s where it gets a bit odd. The red cone has its big hump in red, falling off in sensitivity toward orange and yellow on one side and toward infrared on the other (which none of the cones see). But for whatever reason, way down in violet, the red cone has a little bump in sensitivity again, after not seeing green or blue at all. So violet literally is the blue cone sending a strong signal, but a little bit of the red cone too.

Pigments and computer displays take advantage of this in exactly the same way: add pure red and pure green, and your brain sees it as yellow, because it can’t tell the difference between actual yellow and an exact mix of green and red.

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