White light bends or refracts as it enters and exits the triangular prism, with shorter wavelengths bending the greatest amounts and longer wavelengths refracting less, resulting in a light spectrum of different colors like a rainbow. Prisms are made of glass or other transparent material and cut so the angle of entry and exit maximize this effect.
Light is a part of the electromagnetic spectrum, which includes very long radio waves to very short gamma rays. The visible light spectrum ranges from 400 nanometers to 700 nanometers, with white light resulting from a mixture of all the visible wavelengths. Indigo light has the shortest wavelengths, and red has the longest. With a triangular prism, the deflection of different wavelengths of light causes its dispersal by a prism. When light passes through a transparent parallelogram, all wavelengths deflect the same amount on entering as exiting. However, careful observation reveals that there is a thin blue light on the lower edge of the emerging beam and a red one at its top. In the natural formation of a rainbow, the water droplets in the air each serve as a tiny prism to disperse the light into the various colors seen by the human eye.