Light is a bit like a wave through the air and in the blue light the waves are closer together.
The sky aboves us has a small amount of dust.
Because the blue light waves are closer together they hit more dust.
This means they are more likely to bounce towards us, so we see blue when we look up at the sky.
At sunset the blue waves are more still more likely to hit dust, and so be blocked, so we see red.
Not simple enough, but I gave it a go.
"Let's start with you reading (and demonstrating to me a core competence of) the basic texts of physics leading up to Rayleigh scattering--in this case, that would be Newton, Liebniz, Maxwell, Einstein, Heisenberg, and Schrödinger. When you have those six down, I'd be happy to explain to you why the sky is blue."
Inspired by: https://news.ycombinator.com/item?id=1492061
A correct answer: you need to learn how to read, then some mathematics, then quantum physics, then you can calculate how sunlight scatters on molecules of air. Understanding the physiology of color vision won't hurt, too.
This is not very useful. But at least you see some topics to learn more about, and a simplified picture may be built: sunlight contains some blue light, and it gets stuck in the air, while reds and greens pass in more easily. Hey, you just understood why sunsets are orange and red! Go on.