Evolution of the crash test dummy

Crash testing

Duration: 90 minutes

Resources:

• Card
• 3–5 books (to prop up the card to form a ramp)
• Large sheets of white paper
• Colored pens
• 2 toy cars
• Planning an investigation activity sheet
• Ruler/measuring tape
• Protractor (optional)

Key Learning:

This activity reinforces the students’ understanding of forces and collisions, by asking them to plan and conduct their own toy car crash tests.

Activity instructions:

1. Ask the class to recap the purpose of crash testing. Remind the class that these tests are repeated many times, and the conditions of every test are carefully controlled. This enables scientists and engineers to gather lots of information about what happens during a crash. Tell the class that they are now going to plan and carry out their own crash tests.
2. Organize the students into groups, and give each group the resources.
3. Ask the groups to plan an investigation into how speed affects the force of a collision, using the Planning an investigation activity sheet. Note: Encourage the students to come up with their own questions, setups and methods, and help them to tailor their investigations accordingly. For example:
   • To make the car travel faster, the students could release it from further and further up the ramp (using the ruler or measuring tape to measure the distance each time). The higher up the ramp the car is released, the longer it has to build up speed.
   • To make it easier to observe and record the results of each collision, the groups could place the sheet of white paper on their testing surface, and draw around the starting position of the car at the bottom of the ramp. Then, once each test crash is complete, they can draw around the car’s final position, using a different color of pen for each test to make it easier to keep track.
   • Remind the groups that only one variable should change each time – in this case, the distance that the car travels down the ramp before colliding with the second car. All other variables must stay the same: the position and angle of the car, the angle of the ramp, and so on.
4. Give the groups time to carry out their investigations. Ask them to repeat each test three times, to check that their results are consistent. If they have taken measurements, help them to calculate an average and then plot the data in a graph.
5. Discuss the results as a class. You may want to ask the following prompt questions:
   • What happened to the cars in each collision?
   • How did increasing the distance affect the results?
   • Did you get the exact same results when you repeated the tests?
   • If not, why do you think that is?
   • Were there any variables you weren’t able to control fully?
   • How could the investigation be improved?
   • What does this investigation suggest about how speed affects collisions?
6. Ask the groups to write a paragraph summarizing the results of their crash tests. The groups are likely to find that the collisions push the stationary car backwards and cause the other car to change direction. The faster the car is moving at the point of collision, the larger the force of impact and the more noticeable the results. They may even find that one or both of the cars is knocked over by the larger collisions. They can also draw a labeled diagram showing the forces that act on two cars during a head-on collision.