The listening devices on these pages are a great way of getting people to explore hearing. They’re especially useful for science shows and fairs where it’s really noisy and so other acoustic demos are difficult to do. They’re also great for selfies. They play with the ambient sound.


This swaps the sound going to the left and right ear, so the listener thinks the sound is coming from the wrong direction. The listener can close their eyes and then their friends can play a game of ‘guess where I am?’ just using the sound.

You need:

  • 1x cheap pair of hearing defenders (e.g. only £6)
  • 4x Small diameter plastic water waste pipe (e.g. 21.5 mm) each about 17cm long
  • 4x right angled joints for the plastic pipes
  • 2x funnels (e.g. 14mm diameter)
  • 1x large drill bit (26mm for the connectors we used)
  • Plastic glue (e.g. from hot glue gun)


Pull the foam insert out of the ear defender. Carefully drill a hole in each of the ear defender cups. Push one right-angled connector into each of the cups. Glue the right angled connector into place (we used a hot glue gun). You need to make sure there is a good seal around the tube so sound doesn’t leak in. If that isn’t achieved by the glue, Plasticine can be used to ensure a seal. Cut a hole in the middle of the foam insert (for the end of the plastic connector) and put back in the cup.

For each side use another right angled connector, two pieces of the pipe and a funnel to create the pipework for the sound (see first pictures for layout). This all needs to be fixed securely, especially if it is used as science shows where it will get a lot of abuse. Make sure all the joints are strongly secured with glue.

Put on your head and enjoy!

Lesson starter

If you’re using these in a classroom, there is a lesson starter and follow on activity ideas that were originally developed for Teacher’s TV on this page.

The science

We have two ears because it allows us to locate sound. The is very important for use to be able to track prey and to prevent us getting attacked. Our eyes face front, so it is really important that are ears are very good at hearing things and working our where the sound is coming from, especially when someone dangerous tries to creep up on us from behind. Read more about how we localise sound on this page.

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