Learn

If you’ve been inspired by the story of the first telephone call, you might want to make your own telephone and experiment just like Bell and Watson. See how to get started with the instructions below. Then check out the Experiments List!

• two plastic cups
• string
• paper clips
• a sharpened pencil
• a friend

1. Using the pencil, carefully poke a small hole in the bottom of each plastic cup.
2. Tie a paper clip to one end of the string.
3. Starting from the inside of one of the cups, thread the loose end of the string through the hole. The paper clip will keep the string from going all the way through the hole.
4. Now thread the loose end of the string through the hole in the second cup, but this time starting from the outside of the cup.
5. Tie a second paper clip to the loose end of the string. The paper clip should be inside the cup, just like the the first one.
6. Pull the cups so that the string becomes taut. One person should talk into a cup while another person holds the second cup to their ear.

Experiments:

• What happens if the string isn’t taut?
• How long can you make the string and still hear the other person?
• What happens if you use different size cups?
• What happens if you use two empty soup cans?