Elastic Powered Car

Objectives

• Create a simple toy that uses stored elastic energy in order to move.

Materials

• For Each Student Car :
  rectangular piece of corrugated cardboard (approx. 13 x 15 cm. Read step 1 to ensure you cut it correctly.)
  ruler
  scissors
  bamboo skewer
  masking tape (duct tape or electrical tape will also work)
  2 large (¼ inch) washers
  2 old CDs
  Silly putty or plastiscine
  elastic Band

Key Questions

• Can you explain how the elastic motor makes your car move?
• Describe how energy is changing from one form to another.

What To Do

1. Start by preparing the car body for the axle. Ensure that the long sides of the cardboard are exposed so you can slide the axle across the width of the body. Along the centre of the short side, cut out a notch about 5cm wide and 3.5 to 4cm deep.
2. Insert the axle (skewer) so that the centre of it is exposed in the cut-out notch. Centre the axle and make sure it will rotate in place. Create a tag by wrapping a piece of strong tape in the centre of the axle, leaving a tag strong enough to support the elastic band.
3. Prepare the wheels by attaching a washer to the centre of one CD. Then slide the wheel onto one side of the axle, leaving ample room between the wheel and body of your car. Use more silly putty to stick the wheel to the axle, so that they will move together. Repeat with the other wheel and test to ensure the axle and wheels rotate as a unit.
4. Attach your elastic band “motor” to the top of the car body, and wrap the other end around the tag, winding it several times.
5. Let it go, and see your car in action!
   

Extensions

• Can you improve the car to make it go further?
• How could you store up more potential energy by altering the materials or its design?