The string has to be taut or the vibrations from shouting into one can will not reach the other can. In general it is more efficient to just shout directly at the person and leave out the cans and string.
i think u have to use string that has a hole in it
Try wire
string and 2 cups
The answer is a string and two cans.
no
A can and a string. And telegraphs. :D
2 cans and a string, and cp raidios
thats all they had
no
????
t.v, intercom, radio, cell phones,and cup on a string
tensile strength