What causes the formation of a rainbow?

Question

What causes the formation of a rainbow?

Answer 1

It is the refraction of the light as it passes thru water.Or to put it another way,the light is broken into all the different colors of the light spectrum.

Answer 2

When light strikes mist or rain showers, the light is bent into an arc and split into numerous colors by the process of refraction. This process causes the appearance of seven distinct colors found within the visible portion of the electromagnetic spectrum. The color with the longest wavelength and lowest frequency, which is red, is placed at the top. The color with the shortest wavelength and highest frequency, which is violet, is placed at the bottom. The other colors of the rainbow are orange, yellow, green, blue, and indigo.