The bending of light as it passes from one medium to another is called refraction.

Here's a breakdown:

* Light travels at different speeds in different mediums. For example, light travels faster in air than in water.

* When light enters a new medium at an angle, it changes direction. This change in direction is due to the change in speed.

* The amount of bending depends on the angle of incidence (the angle at which light hits the surface) and the refractive indices of the two mediums. The refractive index is a measure of how much light slows down in a particular medium.

Examples of refraction:

* A straw in a glass of water appears bent.

* A rainbow is formed by the refraction of sunlight through water droplets in the air.

* Lenses in eyeglasses and cameras use refraction to focus light.

Let me know if you want more detail on any of these concepts!