Make a Spoon Bell

Every time a sound is produced it emits a sound wave. You can picture the shape of sound as a wave on the ocean: the sound starts at one end of the wave and spreads out. By the time the wave reaches the shore you can hear it. For an at home example of this phenomenon, take a rubber band and spread it tightly between your fingers. Now thrum the rubber band. The movement of the band creates vibration or sound waves. The following experiment will demonstrate how sound travels, using nothing more than a spoon and a string.

• Metal spoon
• 30 inches of kite string (40 inches for an adult)

1. Tie the handle of the spoon at the midpoint of the string.
2. Wrap the ends of the string around your index fingers (pointer fingers).
3. Place your fingers in your ears.
4. Lean over so that spoon hangs freely and swing the spoon so it taps against a door.
5. Hit the door again, this time harder.

What did you hear?  Was it a soft sound like a bell and then a louder sound like a church bell? The sound came because the spoon vibrated causing sound waves to travel up the string and into your ears. The loudness or quietness of the sound depends on the amplitude (height of the wave).