Whenever we see a rainbow, why do we see red, orange, yellow, etc. on the top and not on the bottom??

Question

Whenever we see a rainbow, why do we see red, orange, yellow, etc. on the top and not on the bottom??

In: Physics

Answer 1

Rainbows are circular, centered on the line that connects you and the light source, and red is on the outside all the way around the circle, so technically it’s on the top, and also on the bottom.

The order is determined by how much the different colors of light bend when refracting at the boundary between air and droplets of water, and how it reflects off the back of the droplet: https://en.wikipedia.org/wiki/Rainbow#/media/File:Rainbow1.svg

Now that’s just the most visible rainbow. There are other paths light can take bouncing around a droplet and some of those have the colors coming out at a different angle and in a different order. (for example, image search for double rainbow)