When light rays enter a medium at an angle, they bend. This phenomenon is called refraction. Here's a breakdown:

* Refraction: The bending of light as it passes from one medium to another (like air to water).

* Angle of Incidence: The angle between the incoming light ray and the normal (a line perpendicular to the surface).

* Angle of Refraction: The angle between the refracted light ray and the normal.

Why does light bend?

Light travels at different speeds in different mediums. When light enters a denser medium (like water), it slows down. This change in speed causes the light to bend.

Here's a simple way to understand it:

Imagine a car driving across a flat field and then entering a muddy field. The car will slow down as it enters the mud. Since one side of the car enters the mud before the other, the car will change direction (bend).

Important points:

* The amount of bending depends on the angle of incidence and the difference in the speed of light in the two mediums.

* If light enters a medium perpendicular to the surface, it does not bend.

Let me know if you'd like more information about refraction!