Stretching rubber | Science | Quizalize & Oak National Academy

Starter quiz

Complete the sentence: The increase in length of a spring with a force acting on it is the ______.
- 'extension' ✓
Which word is used to describe something that returns to its original shape when the forces acting on it are removed?
- bouncy
- rubber
- elastic ✓
- flexible
- stiff
What is the extension of this spring when a force of 30 N acts on it?
- 0 cm
- 5 cm
- 10 cm ✓
- 20 cm
- 25 cm
Which of these is a statement of Hooke's law?
- The total length of a spring is directly proportional to the force acting on it.
- The extension of a spring is directly proportional to the force acting on it. ✓
- The extension of a spring is directly proportional to its mass.
- The extension of a spring is inversely proportional to the force acting on it.
- The total length of a spring is inversely proportional to the force on it.
According to the graph, which of these statements are true?
- The spring obeys Hooke's law for forces below 40 N. ✓
- The spring never obeys Hooke's law.
- The spring does not obey Hooke's law for forces over 45 N. ✓
- The spring does not obey Hooke's law for forces less than 45 N.
- The spring obeys Hooke's law for forces above 45 N.
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.
- '32 cm' ✓

Exit quiz

Match the keyword or phrase with the explanation.
- elastic
  
  ⇔
  
  material returns to its original length after forces are removed ✓
- extension
  
  ⇔
  
  the increase in length when a material is stretched ✓
- directly proportional
  
  ⇔
  
  when one variable increases, the other increases at the same rate ✓
- long molecular chains
  
  ⇔
  
  the structure of rubber ✓
An equal force is applied to both ends of a rubber band. What happens to the rubber band?
- it becomes longer ✓
- it becomes shorter
- it becomes thicker
- it becomes thinner ✓
- it starts to move at a constant speed
The figure shows a rubber band before and after it has been stretched. What is the extension of the band?
- 0 cm
- 2.0 cm
- 2.5 cm ✓
- 9.0 cm
- 12.5 cm
Which of the lines on the graph shows the extension of a rubber band when a force is applied?
- a
- b
- c ✓
- d
Which of the following statements describe the extension of a rubber band when it is stretched?
- The extension is directly proportional to the force applied.
- The rubber band behaves elastically when the force applied is removed. ✓
- The extension increases with the force applied. ✓
- The rubber band obeys Hooke's law.
- The rubber band becomes permanently stretched when a force is applied.
Order the following statements to describe the stretching of a rubber band as an increasing force is applied.
- 1
  
  ⇔
  
  The long chain molecules are closely coiled together.
- 2
  
  ⇔
  
  The long chain molecules begin to uncoil but this is difficult at first.
- 3
  
  ⇔
  
  As more force is added, the molecules unwind and become easier to stretch.
- 4
  
  ⇔
  
  The molecules approach their maximum length, becoming more difficult to stretch.
- 5
  
  ⇔
  
  Eventually, the long chain molecules are fully unwound and stretch no further.

Worksheet

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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.

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.

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.