Tin can telephone
A tin can telephone is a type of voice-transmitting device made up of two tin cans, paper cups or similarly shaped items attached to either end of a taut string or wire.
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[edit] How it works
Sound waves are created as the air vibrates in response to speech or other sounds. The ear collects these sound waves and converts them into nerve impulses which the brain interprets as sound.
When the string is pulled taut and someone speaks into one of the cans, its bottom acts as a diaphragm, converting the sound waves into longitudinal mechanical vibrations which vary the tension of the string. These variations in tension set up waves in the string which travel to the other can, causing its bottom to vibrate in a similar manner as the first can, thus recreating the sound.
[edit] History
In 1664–1665 Robert Hooke experimented with sound transmission through a distended wire.[1] In the centuries before tin cans and paper cups became commonplace, other cups were used and the device was sometimes called the "lovers' telephone". During the 20th century, it came into common use in preschools and elementary schools to teach children about sound vibration.
[edit] See also
[edit] References
- ^ Preface to Micrographia (1665) «I have, by the help of a distended wire, propagated the sound to a very considerable distance in an instant». Micrographia - Extracts From The Preface
