The Sound of Music

Flashlight and snowflakes

After sight, hearing is the most important of our five senses.  Sound is caused by waves, and sounds are made by vibrating objects.  Sounds can vary in two ways: amplitude and pitch.  The amplitude of a wave tells us how much energy was used to produce it.  The greater the amplitude, the greater the volume.  Frequency is the number of waves or vibrations sent out in a specified amount of time; the faster something vibrates, the higher the pitch.

What You Need

  • Small tin can with both ends removed
  • Piece of rubber balloon
  • Small mirror
  • Glue
  • Rubber band

What to Do

  1. Stretch the balloon fragment tightly over one end of the can, using the rubber band to keep it in place.
  2. Glue the piece of mirror to the stretched balloon, slightly off-centre.
  3. Darken the classroom, and move the can near the blackboard.
  4. Hold it away from and at an angle to the blackboard.
  5. Shine the beam of light so that it strikes the mirror and rebounds onto the blackboard.
  6. Have someone speak, sing, shout, or (softly) blow a whistle, into the can.
  7. Observe the reflection that you now see on the blackboard.

Click on this link for a priuter-ready instruction sheet for this activity 


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