White is produced when all colors of the visible spectrum are combined. These colors are red, orange, yellow, green, blue, indigo and violet. They are the colors of the rainbow and can be easily remembered by the mnemonic ROY G BIV.
The colors that are seen are the result of wavelengths of light reflected to the eyes. Normally, eyes cannot distinguish these wavelengths and can only see all colors mixed in a wave of white light. A rainbow is a natural phenomenon that shows the dispersion of the visible light spectrum. Water pockets in the air during rain act as a prism that breaks white light into visible wavelengths of various colors.