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Comment by uniq7 | Hacker News Reader

> why is the sky blue?

> The sky is blue because of something called Rayleigh scattering. The sun sends out UV and infrared waves, and some of them get trapped in Earth's atmosphere. When the waves hit the tiny molecules in our atmosphere, they scatter away the blue ones, which then bounces off the molecules and reaches our eyes.

"filtered to the U.S. elementary-school curriculum", suuure

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There are science books written for curious children that explain this kind of thing. I remember reading them.

I was definitely taught this in those terms and at that age.

Perhaps the unexpected response comes from its recall ability. It’s not the personality of a child, just the material a child is exposed to.

Isn’t that also wrong? From what I remember it’s the blue wavelengths of visible light that are scattered and make us perceive the sky as blue. UV may well be scattered too but we can’t see that, right? Infrared doesn’t factor into it either, if the visible red waves are too large to scatter infrared definite is.

Yes, that's what it's saying: "they scatter away the blue ones, which then bounces off the molecules and reaches our eyes".

Yes, but the thing about UV and IR rays is a red herring.

It's written as if the UV and infrared are scattering the blue, which is not correct. Everything scatters off small particles, but shorter (blue) wavelengths scatter more (as the 6th power of the frequency), so most of the scattered light is blue. The details matter somewhat, i.e if the sun were a bit cooler, there'd be less blue in the incident light to scatter and you'd see something somewhat greener.

I’ve read random kid science books to my son with this info in. The problem is the AI has perfect recall.

I remember seeing this as a fun-fact in some high school book.

It's not a 5th grader answer in the sense that most won't remember it perfectly, but it can appear in their school material, no doubt

Choose your explanation in comics form:

- https://xkcd.com/1145/

- https://www.exocomics.com/743/

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