For Cubs and older. Making tim can telephones with plastic cups (can use tin cans for scouts)
Plastic cups (NOT Styrofoam) OR Clean tin cans with no sharp edges
a sharp needle OR hammer & nail
1. Punch a hole in the base of the cup/tin. This should be as small as possible, Just enough to pass the string through
2. pass the string through the bottom of the cup/tin & tie a knot. tieing around a small piece of toothpick makes a stronger knot that will not come back through the hole
3. repeat with second cup/tin
4. Place one tin/cup to ear, other cup/tin is spoken in to by a friend. Make string tight as you can.
5. Marvel at the mircacle of sound waves