Light can bend
We know light travels in a straight line. But something interesting happens when light passes from one clear material into another, such as from air into water. The light bends. This bending of light is called refraction.
Key idea
Refraction is the bending of light as it passes from one clear material into another, like air to water or air to glass.
Refraction tricks our eyes
Because light bends, things can look different from how they really are.
- A straw in a glass of water looks bent or broken at the water line.
- A swimming pool looks shallower than it really is.
- A coin at the bottom of a bowl of water seems to rise up.
Example
Put a pencil in a glass of water. Look from the side — the pencil seems to break where it enters the water. It is really straight; the light just bends.
Remember
- Refraction happens when light moves between two clear materials.
- Lenses in glasses and magnifying glasses work by refraction.