You’ll need

  • A plastic lunch box
  • Rubber bands (a few different sizes)

What to do

  1. Remove the lid from the lunch box.
  2. Stretch a few different rubber bands around the box.
  3. Get your child to pluck the rubber bands with their fingers and listen to the range of sounds made by the different rubber bands.

Questions to ask

Do all the rubber bands sound the same?

Which rubber band makes the highest sound? Is the band tight or loose?

Which rubber band makes the lowest sound? Is it tight or loose?

What's happening

When your child plucks a rubber band, it vibrates. This makes the box vibrate, and that vibrates the air. The sound then travels through the air to your ear. This is how guitars work. Loose rubber bands vibrate slower than tight bands, so 2 identical rubber bands can make different sounds depending on how tightly they are stretched.