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

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.