Which phenomenon results in a change of direction of light as it passes from one medium to another?

When light passes from one medium to another, such as from air to water, it travels at different speeds in different materials. This change in speed causes the light to change direction, a phenomenon known as refraction. Refraction is responsible for effects such as the bending of a straw appearing broken when placed in a glass of water and the way lenses focus light.

In contrast, reflection involves light bouncing off a surface, while diffraction is the bending of waves around obstacles or through openings. Dispersion occurs when different wavelengths of light are separated, as seen in a prism, but it doesn't inherently involve a change of direction due to a change in medium.