1. Primary rainbow Secondary rainbow Rainbows:
(Blue on bottom; red on top)
(Red on bottom; blue on top)

2. Primary Rainbow: Secondary Rainbow:
- Sunlight is chromatically dispersed when entering a drop of water, separating the colors.
- Analogous to primary rainbow, but with two total internal reflections inside the drop.
- These colors are then total internally reflected at drop’s inner surface.
- Secondary rainbow is observed at about 520.
- Then light is refracted again upon exiting the drop, further increasing the separation of the colors.
- Since not all light is totally internally reflected, the secondary rainbow is dimmer than the primary one since the latter has only ``lost’’ some of the light once.
- Primary rainbow is observed at about 420.