1. Stretching and Squashing
05 December 2018 Objective: To examine the behaviour of materials when forces act on them.

2. Starter (5 mins)
Carefully demonstrate the loading of an elastic band (eye protection for everybody and cushioned floor) getting the students to describe what is happening in terms of forces and equilibrium. Continue until the band snaps or reaches the floor.

3. Main
For the majority of the lesson the students work in small groups to carry out the activity described in the Student’s Book section: P2.11 ‘What happens when forces stretch a spring?’ on page 238.

4. Prediction
You are about to carry out a practical where you will add masses to an elastic band and measure how much it has stretched. Write a prediction for what you think will happen.

5. Practical
See possible practical sheet

6. Mass / kg
Force / N
Length / cm
Extension / cm
0.1 1
0.2 2

7. Graph
Plot a graph of your results

8. Graph
Extension of elastic band (cm)
Force added to elastic band (N)

9. Trend What is the trend shown by the graph?
When you increase the force added
Will this always be the case?

10. Plenary – 5 mins
Structured questions