Do the 2 tin can and a piece of string phones work - if so, how and what would be the maximum string length?

Question

Do the 2 tin can and a piece of string phones work - if so, how and what would be the maximum string length?
I remember trying this as a kid but could never tell wether it was just me hearing my brother as he was only standing 6ft away from me or if the tin can was actually working

Answer 1

Why it Works



When someone speaks or makes a sound, the air ripples or vibrates. The word 'vibrate' means to move up and down, or back and forth rapidly. Our ears collect the sound vibration, or sound waves and send them to our brains. Then we hear the sound.



When you pull the string tight and talk into one of the cans of your tin can telephone, the sound vibrates across the taut string to the other can. The person at the other end of the telephone hears your message after his or her ears collect the sound vibrations and send them to the brain to be processed.



http://www.dsokids.com/2001/dso.asp?PageID=100

Answer 2

It does work. The string must be taught and the quality of sound transmitted is inverse to the length of the string. Your voice, the sound waves cause the can to vibrate and the string vibrates in unison. The tighter the string, the better it transmits the vibration to the other can. Put the can directly over your mouth and hum and be far enough away so that the other person can't hear or barely hear the sound. If they place their ear directly in the can and the string is as tight as possible, they will hear the hum more clearly with the can. This is not unlike the way a needle on an old phonograph transmitted sound. It bounced up and down as the grooves in the record traveled in a circle around it. The vibration of the needle was turned into an electrical signal which was amplified so one could hear it clearly.

Answer 3

Can And String Phone

Answer 4

In theory it would work over an infinite length.



But the maximum string length in practice would depend on the string material. For example, steel wire would be much better than nylon string. it also depends on the mechanical/acoustic properties of the string. A surprisingly broad question.

Answer 5

It works OK, it used to be a common science experiment in Schools in the UK (1960s) as to the distance, I seem to remember it worked over a 30 ft distance.

Answer 6

there shouldnt be a limit on the distance as long as the string is pulled tightly

Answer 7

i know yogurt pots work not sure about max length of string though