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 longitudinal waves in the string which travel to the second can, causing its bottom to vibrate in a similar manner as the first can, thus recreating the sound, which is heard by the second person. The signal can be directed around corners with at least two methods: The first is to create a loop in the string which is then twisted and anchored to another object. The second uses an extra can positioned on the apex of the corner; the string is threaded through the base of the can to avoid coming into contact with the object around which the signal is to be directed. See also History of the telephone Sound-powered telephone Speaking tube References External links Tin Can Telephone How to Make a Tin Can Telephone Traditional toys Telephony equipment