To demonstrate your ability to navigate and map using sound, you will need to apply the principles of sonar. Can you navigate close to unseen objects without crashing into them? Using a jar lid as your sonar tool, you will need to navigate to within 1cm of a wall without knocking into

Activity steps

1. Select your jar lid with safety button and practise clicking. Change the position of your thumbs to get the loudest click.
2. Your challenge is to walk to within 1cm of a wall using your jar lid and the principles of sonar to guide you.
3. Close your eyes and hold the jar lid in front of your face, with the safety button towards you.
4. Click the button to send your sonar signal and walk slowly towards the wall.
5. Can you sense a change in the sound as you near the wall? This is often felt as a slightly ‘fuller’ sensation in the ears as the sound waves from the clicking rebound off the wall to your ears.
6. Keep on practising until you manage to get within 1cm of the wall without touching it first.

More ideas

Experiment with the frequency of your clicking. Does how often you click help you navigate more effectively?

Change the position of your thumbs to alter the pitch of your clicks. How does this affect your navigation skills?

• Jar lid with safety button (this is the raised area on the jar, that can be pressed / clicked down once the jar is opened)

Sonar uses the fact that sound reflects off surfaces to measure depth. This reflective principle is responsible for echoes and some applications of sonar are also known as echolocation.

The Nekton Mission team used sonar to measure the shape of the seafloor. As you can see in the diagram, a sound signal is sent down to the seabed and reflects back up to a receiver. By knowing the speed of sound through the water, and measuring the time it takes for the sound wave to travel from the ship to the seafloor and back again, the team are able to calculate the depth of the water and thus the varying height of the seafloor.

Animals also employ echolocation using biosonar to find their prey and to navigate. Some scientists have referred to this echolocation as an ‘auditory imaging system’, meaning that they can ‘see’ in the dark depths of the ocean.