The double-slit experiment is a demonstration of wave-particle duality. In the experiment, a laser is pointed at two slits which are placed in front of an observing screen. The image to the right shows a set up similar to the experiment. When viewing the pattern on the observing screen, the light is shown to behave both as a particle and a wave. The pattern shows wave behavior in the fact that there is an interference pattern of darker and lighter bands. When a wave passes though the double slits it collides with itself, creating higher and lower energy segments based on how the waves interfere. However, the bands of light are composed of discrete points, showing light's particle behavior. Additionally, when observing at the slits, each photon only goes through one slit, which would not happen if light were exclusively a wave.