Earthwatch Australia Teach Live

Aim: To understand how animals use their senses and sound to communicate over large distances.

Materials: scissors, empty tin cans, string, a hammer, a nail.

To start with, brainstorm as a class group all the animals which can communicate over large distances: do two separate brainstorms for land/air animals and marine/freshwater animals.

Ask students to predict if there is a difference in the range and clarity of the communication, depending on whether the animal is in the air or under water. (sound travels further underwater).

Also ask students to predict how sound can travel through the air, in particular. (Sound waves lessen in strength and clarity over distance, but can reflect or bounce of solid, hard, shiny surfaces. Bat echolocation works so well because the bat’s ears are so sensitive, even if the refracted sound waves are weak, it still picks them up.)

Making a Tin Can Telephone

You will need the above materials before you can make a tin can telephone. Follow the steps to make one.

1. Using the hammer and nail, punch a hole through the base of each can, in the direct center. You might need to get someone grown-up to help you.

2. Pas the string through the base of the holes in each can and tie a double-knot in each.

3. When speaking through the cans, keep the string taut.

What can you notice about using the tin can telephones?

Can you hear clear speech, or just the volume of sounds made?

This must be the reason why bats use the same sounds and tones of different volume to echolocate, as they travel further then different sounds joined together (like when we say a word, eg: b-ir-d)