What you’ll need
2 paper cups
A sharp pencil to poke holes with
1. Cut a long piece of string
2.Poke a small hole on the bottom of each string
3.Thread the string each cup and tie knots at each end to stop it pulling through the cup.
4. Move into position with you and your friend holding the cups at a distance that makes the string tight.
5. One person talks into the cup while the other puts the cup to their ear and listens.
Speaking into the cups creates sound waves which are converted into vibrations at the bottom of the cup. The vibrations travel along the string and are converted back into sound waves at the other end so your friend can hear what you said. Sounds travels through the air but it travels even better thourgh solid such as your cup and string, allowing you to hear sounds that might be too far away when traveling through the air.