Figure 3-1Prisms and a Spectrum (a) When a beam of white light passes through a glass prism, the light is separated or refracted into a rainbow-colored band called a spectrum. The numbers on the right side of the spectrum indicate wavelengths in nanometers (1 nm = 10^–9 m). (b) This drawing of Newton’s experiment illustrates that glass does not add to the color of light, only changes its direction. Because color is not added, this experiment shows that color is an intrinsic property of light.