Hear it!

Activities:

Build a telephone. Use string, cups, and paperclips. Insert string through small hole in bottom of cups and tie to paper a clip. Repeat for other end of 10-20 foot length of string. Pull tight and use as telephone. "Pluck" string and listen on each end. Wrap rubber band around cup (longitudinally) to transmit "music". Put a tuning fork on the string.
Cut pieces of corrugated plastic pipe (3") into small sections, either cylinders or half-pipes. Wrap/stretch rubber bands across to make instrument, experimenting with the tuning.
Cut pieces of PVC pipe of different diameters so that one tube "telescopes" within the other. Change the length of this instrument while "buzzing" (trumpet like) into widest end. Tube length should change the resonant pitch.
Pour different amounts of water into tubes and/or bottles, and blow across the top to hear different pitches.
Two long pieces of corrugated pipe can be uses in similar way to telephone, but using air as medium instead of string. (It sounds really neat!) Experiment with different twists in the pipe, different sounds, etc.
Twirl a 10 foot length of this corrugated pipe around in a circular fashion and it will produce a resonance.
Ropes, elastic cord, and tuning forks will be on hand to demonstrate wave and sound behavior.