Pendulum Bowling

Objectives

• Use ramps, pulleys, levers and pendulums.

• Demonstrate how machines work.

Materials

• Per Group:
  2 chairs, 2 tables or a doorway
  wooden dowel or long ruler
  masking tape
  string
  Wiffle balls or ping pong balls
  several large metal washers
  several clean, empty 500mL water bottles

Key Questions

• Can you knock over the bottles with the pendulums?
• Which bottles are harder to knock down? Why?
• Which pendulums are more successful at knocking down the bottles?
• What did you have to do to knock all the bottles down?

What To Do

1. Set up the chairs or tables with the wooden dowel bridging the gap between them. Tape down the ends of the dowel to secure it. Alternatively, hang the dowel across a doorway.
2. Tie several pieces of string of varying lengths to the dowel.
3. To the hanging end of the strings, securely tie:

• a wiffle ball (or tape a ping pong ball),
• a single washer
• several washers
• You should have a series of pendulums with varying lengths of strings and varying weights.

4. Set up the water bottles on one side of the dowel to act as bowling pins. Set up at several different distances.
5. Try to knock over the bottles by pulling back the pendulums and letting go.

Extensions

• Fill some of the bottles with small amounts of water for an additional challenge.
• Competition — keep score as children take turns with the bowling to see who can knock down the bottles with the fewest number of swings.
• Replace the washers with a small bucket or film canister. Encourage children to alter the weight of the pendulum by adding/removing pennies from the bucket. What is the result?

Other Resources

Science World | YouTube | Exploring the Conservation of Energy (Pendulum Fun!)