Refraction of Light 1
Science: KS3, topic 3.3.21
Refraction
Light changes speed as it travels between two different mediums. Mediums include air, glass and water. The speed change causes a change in direction. The direction change is known as refraction.
Changing speed
- Light changes speed at the boundary between substances.
- Substances (or mediums) include glass, air and water.
- The speed change causes a direction change.
- The process is known as refraction.
Light speed
- Light travels at 300,000 km/s in air.
- Light travels at 225,000 km/s in water.
- Light travels at 200,000 km/s in glass.
Refraction in the real world
- A straw in a glass of water shows refraction.
- The straw looks bent when you look at it.
- An arrow behind a glass of water shows refraction.
- The arrow appears to change direction.
The angle of refraction
- The angle of refraction is measured from the normal to the refracted ray.
- Light can enter glass or water from air.
- So the angle of refraction is less than the angle of incidence.
Test yourself on Refraction of Light 1
When drawing diagrams, which angle is the angle of refraction?
An arrow placed behind a glass of water appears to point in a different direction when viewed through the water. What causes this effect?