Yowie Caller

The mythical creature of the Australian Outback.

 

 

 

Category - Waves & Vibrations

Key Idea - Sound Transmission

 

Purpose - Can be used to demonstrate the relationship between vibration and sound, harmonics and amplification.
Nature -  Demo or Experiment
Materials -  Empty food tin with one end cut out, a shoe lace, a nail punch and hammer
Method - 
  1. Punch a small hole in the bottom of the tin.
  2. Tie a knot in one end of the shoe lace and thread the shoelace through the hole in the tin until the know stops it.
  3. Wet the shoelace
  4. Hold the tin in one hand and, holding the shoelace between your thumb and forefinger, slide your hand away from the tin. A rather unusual noise should be produced.
Safety - Be careful of the sharp edges on an opened tin can
Explanation - As you pull your fingers slide along the shoe lace they cause vibrations that travel up to the tin. The bottom of the tin acts like the membrane on a speaker, and the sides of the tin amplify the sound.
Notes - An interesting investigation would be to vary the size of the tin or the thickness of the shoelace to see what differences there are.

I have taken this device on school camps as a method rousing late sleepers - very effective!

For those who don't know, the Yowie is a creature of Australian Aboriginal legend who lives in the forest and attacks lone travelers. Perhaps this device is a Yowie deterrent, as I have never seen one while using it!

 

This Wizard was generously supplied by Mr. Tim Birkett