How to Make a Play Telephone

Last Updated: February 8, 2023 Tested

Do you wish you could have your very own phone? All you have to do is follow these steps to learn how to make your own tin can and string (or cup and string) telephone. This craft also makes for a good science project to learn about how sound travels.

1

Gather your materials.

Get a piece of string and two empty cans (preferably soup cans). If you don't have cans or you don't want to work with them, you can also use cups (preferably plastic),such as the ones shown here. Plastic is a little easier to work with than metal. Styrofoam cups do not work well because they are soft and spongy and absorb sound instead of transmitting it. In a pinch, you can use disposable paper cups, but plastic and metal take more wear-and-tear.

2

Create holes for the string.

Punch a hole at the bottom of each can just small enough for string to fit through. You might need your parents or teacher to help with this. You can make the hole with a drill, hammer and a nail, or some other sharp, pointed tool. If you are using plastic cups, you can probably just poke a hole with a push pin or any other sharp point. Make the holes only large enough to put the string through and no larger.

3

Put the string through the hole.

Pass the string through the hole and into the bottom of one can or cup. It might help to push the string through with the end of a paper clip or thread it through with a bit of wire.

4

Tie a knot.

Tie a knot in the end of the string that is inside the cup. When you're done, pull the string tight so the knot rests in the bottom of the can. You can tie the string around a little piece of a toothpick if you can't get it to stay with just a knot.

5

Repeat for the other end.

Place the untied end of the string through the bottom of the other can or cup. Tie a knot, as before, and pull the string tight.

6

Get a partner.

Find a partner to test out your creation.

7

Start using your telephone.

Place the open end of one can over your ear and have your partner speak into the open end of the other can. Make the string as tight as you can. If you've made it correctly, you should hear your friend speak, even if it is a long piece of string. Then, talk while your friend listens.

Community Q&A

Question

What can I do if I do not hear it?

Community Answer

Pull the string tighter. Often, we can't hear the sound because the string is too loose.
Question

We used a piece of yarn and two tin cans, why isn't it working?

Community Answer

Yarn has a lot of loose threads that works as a vibration dampener. A taut string will carry the vibration much more cleanly.
Question

Does the size of the cup matter?

Community Answer

Nope, cups of any size should work equally well.

Warnings

Try to use cans that do not have a sharp edge where the lid of the can was removed.

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Be careful when you punch the hole in the can.

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