Our analysis does not yet explain why the rainbow has different colors or why it appears as an arc. Light hitting water droplets is refracted and reflected into an observer's eyes. Question 11 Give a geometric explanation why the rainbow looks like part of a circle. Recall that different colored light travels at different speeds through water so that, for instance, the index of refraction for red light in water is about 1.3318 and for violet light it is 1.3435.
Rainbows have colors because water refracts different wavelengths of light slightly differently.
This lab is based on a module developed by Steven Janke and published in Modules in Undergraduate Mathematics and its Applications , 1992.