Light Sound and Waves

Singing Paperclip Trick

Enrichment Activity for 5-11 11-14

What you need

  • A paperclip
  • Water
  • Two identical glasses
  • Marvin bets Milo that he can make the paperclip move without touching it


  1. Put equal amounts of water in both glasses and stand them next to each other but not touching
  2. Straighten out the paperclip into a straight wire, then bend it slightly (it should be shaped more-or-less like a boomerang), Balance it on the rim of one of the glasses
  3. With a wet finger, rub around the rim of the other glass until it "sings"
  4. The paperclip moves!

Results and Explanation

Rubbing the glass makes it vibrate at its natural frequency. Because the other glass is identical it has the same natural frequency and the sound waves from the other glass make it vibrate as well - so the paperclip moves.

is a special case of Oscillation
is exhibited by Resonating System
can be analysed using the quantity Resonant Frequency Natural Frequency
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