A rainbow is a multi-colored, arc-shaped phenomenon that can appear in the sky. The colors of a rainbow are produced by the reflection and dispersion of light through water droplets present in the atmosphere. An observer may perceive a rainbow to be located either near or far away, however, this phenomenon is not actually located at any specific spot. Instead, the appearance of a rainbow depends entirely upon the position of the observer in relation to the direction of light. In essence, a rainbow is an optical illusion.
Rainbows present a spectrum made up of seven colors in a specific order. In fact, school children in many English-speaking countries are taught to remember the name “Roy G. Biv” as a mnemonic device for remembering the colors of a rainbow and their order. “Roy G. Biv” stands for: red, orange, yellow, green, blue, indigo, and violet. The outer edge of the rainbow arc is red, while the inner edge is violet.