One of the most interesting sources of color in nature is the rainbow. The details get somewhat complicated, but FIGURE 35.19a shows that the basic cause of the rainbow is a combination of refraction, reflection, and dispersion.

FIGURE 35.19 Light seen in a rainbow has undergone $\text{refraction}+\text{reflection}+\text{refraction}$ in a raindrop.

FIGURE 35.19 Full Alternative Text

Figure 35.19a might lead you to think that the top edge of a rainbow is violet. In fact, the top edge is red, and violet is on the bottom. The rays leaving the drop in Figure 35.19a are spreading apart, so they can’t all reach your eye. As FIGURE 35.19b shows, a ray of red light reaching your eye comes from a drop higher in the sky than a ray of violet light. In other words, the colors you see in a rainbow refract toward your eye from different raindrops, not from the same drop. You have to look higher in the sky to see the red light than to see the violet light.