Quiet please! Fighting noise pollution

Activity 1

Vibration and sound

This activity demonstrates that sound originates in a vibrating body and is transmitted through matter to the ear.

Materials (for each person)

  • plastic ruler

Procedure

  1. Hold the ruler firmly on the edge of a desk or table so that about 25 centimetres extends over the edge.
  2. Flick the free end of the ruler with your fingers and listen for any sound it makes.
  3. Look closely at the way the ruler is moving.
  4. Move the ruler back so that only about 15 centimetres extends over the edge and repeat the procedure.
  5. Compare your observations.

Teachers notes

Students should observe the following:

  • Flicking the ruler resulted in an up and down motion (vibration).
  • The second distance (15 centimetres) produced a faster vibration and should have generated a sound that was easier to hear.
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Posted June 2002.