String Can phone?

Question

My son wants to make one of those two can's with a string phones? Anyone ever done this as Science Project?

Answer 1

Yep I have.

Get some empty cans or even those plastic cups (Solo).  Make a tiny hole in the middle of the bottom.  Thread the string through and tie a knot big enough to stop the string slipping through the hole.  Do this on both ends.  Hold the string tight and you can talk into one end and hear it on the other.

Try and find good string, not that cheap plastic kind.

Oh I just noticed this was home schooling.  The principle you are teaching here is that sound waves can travel along an object like a piece of string.  The vibration of sound is transferred down the string from one end to the other where that vibration resonates in the cup at the other end.

It's a similar concept to the old analogue phones.  Only there the vibration was transformed into an electrical current and then reproduced with a loudspeaker at the other end.

These days the sound is just digitally sampled and transferred as binary digits.  But that's probably a more advanced class.