Refraction How does refraction affect light rays Starter

$Refraction How does refraction affect light rays? Starter: what is going on in this$

$Effects of refraction Light from the part of the pencil in the water is$

$Refraction at an air-glass boundary$

$Refraction investigation Place a glass block on a sheet of paper and draw around$

$Refraction ray diagram$

$What happens during refraction?$

$For light travelling from air to glass… • the angle of refraction is always$

$Snells Law – The refractive index • The angle of incidence can be worked$

Snells Law • For 1 material the calculation Sin i Sin r Always gives

$Refraction at an air-glass boundary$

Use your calculators to fill in the rest of this table i r Sin

For a non transparent material… • The normal rules do not apply…. Instead :

$Plenary • What are the key difference between refraction and reflection$

Slides: 15

Download presentation

$Refraction How does refraction affect light rays? Starter: what is going on in this$

Refraction How does refraction affect light rays? Starter: what is going on in this picture? Can you explain it?

Demos

$Effects of refraction Light from the part of the pencil in the water is$

Effects of refraction Light from the part of the pencil in the water is refracted as it travels from the water into the air, making it appear bent. How does refraction make this stone look closer to the surface of the water than it really is? Light rays from the stone are refracted as they leave the water. The brain assumes the rays have travelled in straight lines, and is fooled into forming an image where it thinks the light rays came from.

$Refraction at an air-glass boundary$

Refraction at an air-glass boundary

$Refraction investigation Place a glass block on a sheet of paper and draw around$

Refraction investigation Place a glass block on a sheet of paper and draw around it. Draw a normal at 90° to the top surface of the block. Angle of incidence Angle of refraction 10 20 30

$Refraction ray diagram$

Refraction ray diagram

$What happens during refraction?$

What happens during refraction?

$For light travelling from air to glass… • the angle of refraction is always$

For light travelling from air to glass… • the angle of refraction is always less than the angle of incidence. • the greater the angle of incidence, i, the greater the angle of refraction, r. • Incidence = i • Refraction = r

$Snells Law – The refractive index • The angle of incidence can be worked$

Snells Law – The refractive index • The angle of incidence can be worked out using Snells Law. . • Use this to work out the refractive index for your 3 lines.

Snells Law • For 1 material the calculation Sin i Sin r Always gives the same answer (depending on accuracy of measurement) Calculate the mean value of sin i/sin r to get an accurate refractive index.

$Refraction at an air-glass boundary$

Refraction at an air-glass boundary

Use your calculators to fill in the rest of this table i r Sin i Sin r Sin i/sin r 10. 0 6. 5 0. 17 0. 11 1. 55 20. 0 13. 0 0. 34 0. 22 1. 55 30. 0 19. 0 0. 5 0. 33 1. 52 Work out the average of the last column. This is your refractive index. average=1. 53 Gerald fingers rabbits

For a non transparent material… • The normal rules do not apply…. Instead : the light ray is refracted away from the normal. The larger the angle the larger the angle of refraction.

• Complete the past paper question

$Plenary • What are the key difference between refraction and reflection$

Plenary • What are the key difference between refraction and reflection