What is Rayleigh scattering?

Rayleigh scattering is when light bounces off tiny things in the air and changes color.

Imagine you're playing with a ball in a room full of small, invisible blocks, like the ones you stack to build towers. When the ball (which is like a light wave) hits one of these blocks, it bounces back. But depending on the size of the block, the ball might come back a different color.

When light travels through the sky, it meets tiny particles, think of them as super small dust grains or molecules, that are much smaller than the wavelength of the light. These particles scatter the light in all directions. Blue and violet light get scattered more because they have shorter wavelengths, just like how a small ball bounces around more easily in a room full of little blocks.

On a clear day, the sky looks blue because the scattered blue light reaches our eyes from all directions. At sunrise or sunset, the light has to travel through more air, so most of the blue gets scattered away, and we see reds and oranges instead, like when you look at a toy car under a red lamp.

This is why the sky changes colors during the day, it's just light playing with tiny particles in the air!