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Clucking Cups

An image showing a cup with wet string that is being pulled to make a noise

Don’t be a chicken- give this noisy experiment a go and see how to make sounds louder!

Australian Curriculum links

  • Science > Physical Sciences > Year 1 > ACSSU020
  • Science > Biological Sciences > Year 1 > ACSSU017

You’ll need

  • 60cm string, cotton twine is best
  • Plastic cup
  • Paperclip
  • Water

Try this

  1. Poke a small hole in the centre of the base of the plastic cup. The hole should be large enough to just allow the string to poke through. If you are doing this with a class, you may want to make the holes beforehand using a cordless drill.
  2. Tie one end of the string to the paperclip and then thread the other end of the string through the hole in the cup. The string should hang through the body of the cup, with the paperclip on the outside, like a bell with the string hanging down through it.
  3. Wet the string with the water and your index finger and thumb.
  4. Hold the cup firmly in one hand with the string hanging down towards the floor. With the other hand, use your wet index finger and thumb to pinch the string. Pull your fingers downwards in a jerky motion and listen to the cup “cluck!”

Further investigation

  • Try repeating the experiment with different sized containers, like a bucket or a smaller cup. How does this change the sound? Is it louder or softer? Is it higher or lower?
  • Try using different types of string. Do some work better than others? Why do you think this is?

What’s happening?

When you pinch the string with wet fingers and pull down, it creates a slip and grip motion which causes the string to vibrate. The vibrations travel up the string and make the cup vibrate. The air surrounding the cup gets bumped and vibrates, creating sound waves. As the cup causes more air to vibrate, this makes a louder sound than the string vibrating on its own

Further information

For younger audiences, you can turn your clucking cup into an animal. What features does a chicken have? Or does it sound more like a duck? The smaller cup will often give a high pitch squeak like a mouse, while a bucket will sound like a cow. What external features do these animals have to identify them?

Once you have a whole farmyard of animals, you could even try a whole class rendition of “Old McDonald had a Farm”… with a cluck-cluck here and a cluck-cluck there…!