Would you like to have your own phone? Follow these simple steps to build a phone out of a string or twine by joining two empty cans or two plastic cups together. This article is also a valid starting point for a scientific experiment on sound transmission.
Steps
Step 1. Get a string and two empty cans (such as tomato puree or bean cans, although tuna cans are fine too)
If you don't have cans or are having trouble with sharp edges, get two plastic cups, like the ones used in the example. Plastic is easier to use than metal. Styrofoam glasses are too spongy and absorb sound rather than transmit it.
Step 2. Pierce the base of the can or glass
The hole must be thin so that the twine will pass through it. If necessary, get an adult to help you pierce the containers. To drill the hole, you can use any pointed object. Remember to make holes of just enough diameter to insert the twine.
Step 3. Thread the twine through the holes, using a paper clip or other stiff tool to insert the twine in the right place
Step 4. Tie each end of the string inside the can or glass
When you have finished tying, pull the string to make sure that the knots are positioned against the bottom of the vessels. If a knot tends to go through the hole, you can stop it using a toothpick or other locking system.
Step 5. Repeat on the opposite end, and tighten the string
Step 6. Find a mate to talk to
Step 7. Place the open container on your ear, and listen to what your partner tells you while speaking inside the other container
Stretch the twine as tight as possible. If you've built the phone correctly, you should hear what the other person is saying to you, even if the string is long. Then switch and speak so that the other person hears what you say.
Advice
- If the string is tight, the transmission of the voice works better.
- Try speaking from around a corner.
- Try talking inside and outside the container, to test the difference in voice transmission.
- If you use fishing line instead of ordinary twine, the sound is transmitted much better.
Warnings
- Do not use cans that have sharp edges.
- Be very careful when you pierce the bottom of the can.
