Illustration demonstrating how a prism refracts beams of light in different colours. The refracted rays of different colours are bent at slightly different angles. Blue and violet, which have shorter wavelengths, are refracted more than red and orange, which have longer wavelengths. This phenomenon is known as dispersion. If all the rays were of the same colour, they would exit the prism parallel to each other. The simulation uses flint glass, which is a dense material with a high refractive index and high dispersion.