Stretching rubber
I can investigate the extension of a rubber band, and compare the behaviour to that of a spring.
- Year 9
Stretching rubber
I can investigate the extension of a rubber band, and compare the behaviour to that of a spring.
Lesson details
Key learning points
- A rubber band is elastic because it returns to its original length when a force is removed.
- The extension of a rubber band increases different amounts for each equal sized increase in force.
- The extension of a spring is not directly proportional to the force applied.
- The extension pattern is explained by the behaviour of molecular chains in the rubber.
Keywords
Extension - The extension of a rubber band is its change in length.
Directly proportional - Variables are directly proportional when one is a constant multiple of the other.
Elastic - A rubber band is elastic; it returns to its original length after forces are removed from it.
Long molecular chains - Rubber contains long molecular chains, that uncoil when it stretches.
Common misconception
Pupils find it challenging to link the shape of a line graph with physical change in the real world.
Compare two sections of the graph, using the amount of extra stretch per newton as a measure of how easy the rubber band is to stretch.
Content guidance
- Risk assessment required - equipment
Supervision
Adult supervision required
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.Complete the sentence: The increase in length of a spring with a force acting on it is the .
Q2.Which word is used to describe something that returns to its original shape when the forces acting on it are removed?
Q3.What is the extension of this spring when a force of 30 N acts on it?
Q4.Which of these is a statement of Hooke's law?
Q5.According to the graph, which of these statements are true?
Q6.A pupil collects the data shown during a spring experiment. Use the data to predict the extension if the force used was 8 N. Give your answer in cm to the nearest whole number.
Assessment exit quiz
6 Questions
Q1.Match the keyword or phrase with the explanation.
Q2.An equal force is applied to both ends of a rubber band. What happens to the rubber band?
Q3.The figure shows a rubber band before and after it has been stretched. What is the extension of the band?
Q4.Which of the lines on the graph shows the extension of a rubber band when a force is applied?
