String Telephone
INTRODUCTION
Besides traveling through air, sound can also travel through solid objects.
MATERIALS
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2 paper or plastic cups (empty yogurt
containers work well)
1 piece of string about 2 meters long
Scissors
1 pushpin
2 paperclips
WHAT TO DO
1. Poke a small hole in the bottom of each cup with the pushpin.
2. Thread the string through the holes and tie a paperclip to each end of the string to
ensure that it is secured inside the cup.
3. Give one cup to a friend, and take the cups far apart, so that the string is tight.
Talk and listen to each other through the string telephone.
QUESTIONS
1. What happens if the string hangs loose?
2. What happens if you hold the string?
3. What happens if you connect three or four string telephones together?
SUMMARY
When you talk into the cup, you cause it to vibrate. This in turn causes the string to
vibrate, which causes the cup on the other end of the string to vibrate. Whoever is
listening hears the vibrations caused by your voice after they have traveled through the
cups and the string.
SOURCES
"SOUND: Science Activities." Graham Peacock, Wayland Publishers, Ltd.: New York,
1993, p. 20-21.
"Sound Science." Etta Kaner, 1991, Addison-Wesley, New York, p. 88-89.
"Sound." K. L. Siepak, 1994, Carson-Dellosa Publishing Co., p. 31-32.
© S. Olesik, WOW Project, Ohio State University, 2000.
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