Crumple zones: crash into wall worksheet other worksheets
for use with the Crumple zones: crash into wall simulation
from the materialworlds Crash simulations
© materialworlds.com 2002

Investigate the differences a crumple zone makes for a car and its passengers in a collision.

The crash simulations repeat automatically. Pause the simulation to examine a particular moment.
Adjust the "Time" control to slow the simulation to study particular events in fine detail.
To examine the graphs, pause the simulation once the collisions are over, then click on the links for the different graphs.
The blue arrows in the simulation indicate the velocity of each part of a vehicle - the red arrows show the forces.
Simulation time is displayed in the toolbar under the simulation.

Watch what happens to each car throughout its collision with the wall.
1. For the car without crumple zones...
a) On hitting the wall, which part of the car stops first?
b) Which is the last part of the car to stop moving towards the wall? How long does it take to stop?
c) How do different parts of the car move from now onwards?
d) How is the car distorted thoughout the collision? Is this temporary or permanent?

2. For the car with crumple zones...
a) On hitting the wall, which part of the car stops first?
b) Which is the last part of the car to stop moving towards the wall? How long does it take to stop?
c) How do different parts of the car move from now onwards?
d) How is the car distorted thoughout the collision? Is this temporary or permanent?

3. What differences did you notice between the cars with and without crumple zones?

4. The diagram accompanying this worksheet collects all the graphs together and adds vertical lines representing a series of moments (i - v) through the collision. In answering the following questions you may find it useful to slow down and pause the simulation - matching the movement of the cars to the graphs as they are drawn.
a) At which moment (of moments i - v) do the cars hit the wall? What changes in which graphs indicate that this happened?
b) How would you describe their motion before they hit the wall?
c) At what moment does the passenger compartment of both cars feel the effect of the collision? How can you tell this from the graphs?
d) Why is there a delay between the front of either car hitting the wall and the passenger compartment being affected?
At what moment does the car without crumple zones...
e) start to move away from the wall? How can you tell this from the graphs?
f) lose contact with the wall? How can you tell this from the graphs?
At what moment does the car with crumple zones...
g) start to move away from the wall? How can you tell this from the graphs?
h) lose contact with the wall? How can you tell this from the graphs?
i) Why don't "starting to move away from the wall" and "losing contact with the wall" happen at exactly the same moment?

5.
a) How does the acceleration within the passenger compartment of each car compare?
b) What are the safety implications of this?

6. Compare the passenger compartment velocity graphs for each vehicle.
How do they match the acceleration graphs?

7. After the car without crumple zones rebounds off the wall, it does something you might not have expected.
What is this and how might it affect the passengers?