Schematic animation of a continuous beam of light being dispersed by a prism. The white beam represents many wavelengths of visible light, of which 7 are shown, as they travel through a vacuum with equal speeds c. The prism causes the light to slow down, which bends its path by the process of refraction. This effect occurs more strongly in the shorter wavelengths (violet end) than in the longer wavelengths (red end), thereby dispersing the constituents. As exiting the prism, each component returns to the same original speed and is refracted again.
