1. Diffraction
Diffraction is the spreading out of a wave as it goes passed an obstacle or through an aperture
When the wavelength is small compared to the aperture the amount of diffraction is minimal
Most of the energy associated with the waves is propagated in the same direction as the incident waves.
When the wavelength is comparable to the opening then diffraction takes place.
There is considerable sideways spreading, i.e. considerable diffraction

2. Diffraction
Waves spread as they pass an obstacle or through an opening

3. Diffraction
Diffraction is most when the opening or obstacle is similar in size to the wavelength of the wave

4. Diffraction
Diffraction is most when the opening or obstacle is similar in size to the wavelength of the wave

5.                                                                 
                                                                
                                                                
                                                                
Diffraction
That’s why we can hear people around a wall but not see them!

6. Diffraction + Interference = ?
                                                                
                                                                
                                                                
                                                                
Diffraction + Interference = ?

7. Tuning Fork
What does the wave pattern look like – from the top?

8. One Sound + One Sound = ?
Destructive Interference causes silent areas