A telephone

MATERIALS:
- Two plastic glasses
- 6 - 8 m. of fishing line
- 2 clips
- a cutter


INSTRUCTIONS:
- Make a hole on the bottom of the plastic glasses.  
- Put one end of the fishing line into the hole.
- Make a knot to a clip. Do the same with the other end.
- Tighten the fishing line and talk to a friend.


WHY?:
The  sound travels better through a solid (fishing line) than the air.