Pupil with plasma ball

Kit List

  • Medium sized bowl
  • Cling film
  • Hundreds and thousands (cake sprinkles)


  • Tray and wooden spoon

Safety Notice

Ask an adult to help you with this experiment

What to do

  1. Find all of the items listed in the equipment list.
  2. Tightly cover the top of the bowl with the cling film making sure it is nice and secure. You have just made a drum, but we’re not going to play this with a stick or spoon.
  3. Sprinkle a small amount of hundreds and thousands into the centre of the cling film. This will allow you to see the power of your voice.
  4. You are now ready to start experimenting with the power of you voice.
  5. With your mouth close to the bowl, start to hum quietly and slowly get louder. What do you notice?
  6. Try humming at different pitches, such as a high note and a low note. How does this affect how the sprinkles move?

What's happening

Sound travels in waves. When you talk or hum, waves of sound are produced and travel through the air.  When these waves reach the cling film they cause it to vibrate.  The vibrating cling film then causes the sprinkles to vibrate, and dance around, all down to the power of your voice.

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