Refraction - GCSE Biology Definition

Refraction is the bending of light as it passes from one material to another with a different density, such as from air into water. This occurs because light changes speed in different materials. A common example is when a straw appears bent at the surface of a glass of water. Refraction is important in biology because it helps the eye focus light. When light enters the eye, it is refracted by the cornea and lens so that it focuses on the retina, allowing us to see clearly.