Crash Science: How Do Bumpers and Helmets Save Lives?
Shared by A STEM Educator
Students will plan and carry out investigations using marbles to observe and explain how energy is transferred and transformed during collisions, connecting findings to engineering design in automobile bumpers and sports helmets (4-PS3-3).
Lesson Overview
Students investigate energy transfer during collisions using marbles, then connect findings to real-world bumper and helmet engineering. They develop evidence-based explanations for how energy transforms during impacts.
Materials
- Marbles of different sizes (small and large)
- Meter sticks or rulers
- Masking tape (to mark starting positions)
- Foam padding, bubble wrap, and cardboard (bumper materials)
- Grooved ruler or cardboard ramp for marble track
- Balance scale or gram masses
- Recording sheets and pencils
- Newton's cradle demonstration set (or 5 identical marbles on a string)
- Plastic cups (to catch marbles)
- Graph paper
Scaffolded Task Progression
Place a grooved ruler flat on your desk as a marble track. Set one marble (the TARGET marble) at rest at the center mark. Roll a second marble (the STRIKER marble) from the end of the ruler so it hits the target marble.
Observe and record:
- What happened to the STRIKER marble after the collision?
- What happened to the TARGET marble after the collision?
- Did you hear or feel anything at the moment of impact?
Draw a before-and-after diagram showing both marbles' positions and directions.
[ Interactive graph / diagram — available in the full lesson ]
Repeat the marble collision THREE times, each time changing the ANGLE at which the striker hits the target (head-on, slight angle left, slight angle right). Record what happens to the direction each marble travels after the collision.
Then answer: Does the total amount of motion seem to increase, decrease, or stay the same after a collision? Use your observations as evidence.
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