Understanding Refraction of Light

1. Refraction of Light

2. The bending of light is called refraction. Refraction happens when light travels from one material (e.g. air) into a different material (e.g. glass or water).

3. i = angle of incident r = angle of refraction normal Incident ray i refracted ray r Glass block Air normal

4. Light is refracted because its speed changes when it enters another medium. Demo Light travels more slowly in glass than in air In air (and a vacuum) light travels at 300,000,000 m/s (3 x 108 m/s), in glass its speed falls to 200,000,000 m/s (2 x 108 m/s).

5. normal i Air Glass block r The angle between the ray entering the block and the normal is called the angle of incidence (i). The angle between the ray inside the block and the normal is called the angle of refraction (r).

6. normal i Air Glass block r Glass block Air Laws of Refraction When a ray of light passes from an opticallyless dense medium to an opticallymore dense medium, at an angle, the ray is refracted towards the normal. normal When a ray of light passes from an opticallymore dense medium to an opticallyless dense medium, at an angle, the ray is refracted away from the normal.

7. What do you think will happen to a ray of light striking an air-glass boundary at 90o? Glass block Air

8. Real depth Apparent depth I O O

11. Red Richard Orange of Yellow York Green Gave Blue Battle Indigo In Violet Vain

13. The light enters your eye through the transparent cornea, passes through the lens and is focused on the retina. The retina is sensitive to light and sends messages to your brain by way of the optic nerve. The iris changes in size to vary the amount of light that enters through the pupil.