1. Reflection, Refraction, Diffraction
Normal
Incidence
Ray
Medium
Describe reflection, refraction and diffraction
Complete ray diagrams for each
State the law of reflection
Identify how to investigate the effect of the angle of incidence on the angle of refraction
To identify which size of aperture will give rise to the greatest degree of diffraction

2. Angle of incidence = angle of reflection
Draw normal line at 90° to boundary
Angles are drawn between ray and normal.
Angle of incidence = angle of reflection

3. Refraction When light moves across a change in medium, it will refract
Refraction is a change in the direction of a wave due to a change in its speed
If the waves enter a dense medium they will slow down. This causes them to bend towards the normal.

4. Diffraction
What can you observe here that is happening to the pattern of the waves as they enter the inlet?
Why are they doing this?

5. When might maximum diffraction occur?
As waves pass through an aperture (gap) or attempt to pass around an obstacle they will spread out. This phenomenon is called DIFFRACTION
The degree that waves diffract will be affected by the size of the aperture or obstacle.
State the relationship shown here in these images between the size of the aperture and the effect of diffraction
When might maximum diffraction occur?

6. The blue car in the photograph is sounding its alarm.
Contextual Question
The blue car in the photograph is sounding its alarm.
Explain using the terms you have just learned, why the lady in the red coat cannot see the truck but is however able to hear it!