The sky is blue. Or is it? Sometimes it's orange. Or red. Why does it change? What color is the sky actually? PBS explains it so well you wished someone did the same when you were in school. They explain:
In this episode, I'll tell you not only why the sky is blue, but why it's red at sunset. It turns out, those colors are all part of the same sunbeam. And when you're looking at a blue sky, you could be sharing a special moment with someone thousands of miles away. Next time a kid (or the kid inside you) wants to know why the sky is blue, you'll have science to back you up!
[PBS It's Okay To Be Smart via BoingBoing]