The Formation of a Rainbow

Diagram showing how primary and secondary rainbows are formed due to the light propagation in spherical droplets.

1. Spherical droplet
2. Places where internal reflection of the light occurs
3. Primary rainbow
4. Places where refraction of the light occurs
5. Secondary rainbow
6. Incoming beams of white light
7. Path of light contributing to primary rainbow
8. Path of light contributing to secondary rainbow
9. Observer
10. Region forming the primary rainbow
11. Region forming the secondary raimbow
12. Zone in the atmosphere holding countless tiny spherical droplets

Author: Peo

CC BY-SA 3.0