Tin can telephone

A corded phone (also Tin Can Phone, Bindfadentelefon ) is a toy that can be built with easily accessible means.

It consists of two side opened, empty cans or cardboard or plastic cups which are connected to a several meters long, tense cord free. The two cord ends are each guided through a central hole in the bottom of the box and is prevented by means of a node from hinauszurutschen again.

The sound that comes into the opening of a socket is transmitted in tense cord as a longitudinal wave to the other box and there heard again. The sound may be transmitted in both directions simultaneously and symmetrically. In practice, however, one speaks rather alternately, as it keeps the socket to listen often to your ear. The cans act both in speaking and listening as the resonator and thus reinforcing.

Telephones are regarded as the forerunner of the child's CB radio, because both bi- and uni-directional communication is possible.

The first experiment documented in writing this appears to come from Robert Hooke in 1664. He wrote:

"I have, by the help of a distended wire, propagated the sound to a very Considerable distance in at instant"

In the collection of the National Museum of the American Indian it is a about 1200 to 1400 years old corded phone from the Andes.