The formation of a rainbow is a classic example of the interplay of several optical phenomena within raindrops. Sunlight, which is white light, encounters a raindrop and undergoes refraction as it enters. Subsequently, the different wavelengths (colors) of light bend at slightly different angles, a process known as dispersion, separating the white light into its constituent colors. This dispersed light then travels to the back of the raindrop and is reflected internally. Finally, as the light exits the raindrop and refracts again, the separation of colors becomes even more pronounced, allowing us to perceive the distinct spectrum of the rainbow.