OUTCOME
By the end of this lesson you will be able to describe and analyse the pattern of interference in 2D, determining the path difference from nodes and antinodes from the sources.
Waves interfere when they interact from two different sources on the plane. If this is sound, we would hear loud and soft point where the waves constructively and destructive interfere. the path difference to the point will vary depending if the point is anode or antinode
LEARNING TASKS
Explain
1. Explain how constructive and destructive interference are related to nodes and anti nodes
2. What is a path difference
3. Give a rule to find the path difference for a point on a node
4. Give a rule to find the path difference on an anti-node
Explore and Elaborate
Map the interference patter activity
Activity: Mapping nodal lines
Demo: interference in the ripple tank
Look at these PhET simulations
Evaluate
Try Ex 9.6
WS 1 - Mechanical Waves