1. Explaining Constructive and Destructive Interference

2. + Constructive Interference Imagine 2 waves passing through each other ‘ in phase’ - which means they are going up and down at the same time

3. + Constructive Interference Think about the upward displacement for each wave….

4. + Constructive Interference … and the downward displacement

5. + = Constructive Interference The wave produced when these ‘in phase’ waves ‘interfere’ (overlap) combines the upward and downward displacement

6. + Destructive Interference Imagine 2 waves passing through each other ‘ out of phase’ - which means they are going up & down at opposite times

7. + Think about the upward displacement for each wave…. Destructive Interference

8. + … and the downward displacement Destructive Interference

9. + = The wave produced when these ‘out of phase’ waves ‘interfere’ cancelling out the upward & downward displacements Destructive Interference