What does refraction involve?

Refraction involves waves changing direction at a boundary. When a wave, such as light, travels from one medium into another (for example, from air into glass), it changes speed due to the different optical densities of the materials. This change in speed causes the wave to bend, or refract, as it crosses the boundary separating the two media.

This fundamental property is observed in various scenarios, such as when light passes through a lens or a prism, causing the different wavelengths (colors) of light to bend at different angles. Understanding refraction is essential in fields like optics, where it's used to design glasses, cameras, and other optical devices.