What phenomenon occurs when light moves through a prism?

When light moves through a prism, the phenomenon that occurs is refraction. Refraction happens because light travels at different speeds in different mediums. In the case of a prism, as light enters and exits the prism, it slows down and bends due to the change in medium from air to glass and back to air.

This bending of light leads to the separation of colors that make up white light, a process called dispersion. When light is refracted through a prism, each color has a different wavelength and bends at a different angle—resulting in the distinct spectrum of colors, commonly referred to as a rainbow.

Thus, refraction is fundamental to understanding how prisms work and why they can disperse light into its constituent colors.