Here is a wonderful lecture with real-world demonstrations of the effect:

https://www.youtube.com/watch?v=4a0FbQdH3dY

https://en.wikipedia.org/wiki/Rayleigh_scattering

I do have a question though.

The article says:

> blue and violet have the closest frequencies to a “resonant frequency” of nitrogen and oxygen molecules’s electron clouds

I thought it was more to do with the photon frequency matching the physical size of the air molecules? Or is that the same as its resonant frequency?

It’s not. It’s raining here.

Interesting here is: Actually, for most blue butterflies, it’s not even a pigment-it’s just a trick of the light. Since blue is so rare in the biological world (hardly any plants or animals can produce real blue chemicals), they evolved structural colors. Their wings have these microscopic ridges that reflect blue light while canceling out other colors.

It’s basically the same reason the sky looks blue, just built into a wing. If you were to look at the wings from a different angle or get them wet, the blue often disappears because you're messing with that physical structure

Obligatory xkcd: "Sky Color" https://m.xkcd.com/1145/

Obligatory xkcd[2]: "Rayleigh Scattering" https://m.xkcd.com/1818/

Others?

For the sunset example then, a natural question (for me) is then why isn't the sky green in the transition from blue sky to red sunset sky?

Going to be that guy, even though I think this is a really nice work overall...

But the winking and "cool guy" emojis are so grating. In general, technical explanations that apologize for themselves with constant reassurances like "don't worry" and "it's actually simple" undermine their own aim.

Your job -- if you're making content for people with double digit ages -- is to make the explanation as clear as you can, not to patronize and emotionally hand-hold the reader.