Refraction

Refraction is the bending of light as it passes from one medium to another, like from air into water. This occurs because light travels at different speeds in different materials. For example, when light enters water, it slows down and changes direction, which is why a straw in a glass of water appears bent. This bending effect is described by the law of refraction, also known as Snell's Law, which relates the angles of incidence and refraction to the indices of refraction of the two media. Refraction is responsible for effects like lenses focusing light and the distortion seen in a swimming pool.