Ok, so the AP Chemistry test is behind me and now our persutes in that class are turning to a bit more light hearted activities and our class has decided to put on a chemistry and physics show for our parents and for younger kids (4th-6th grade probably). The idea is to do a whole bunch of chemistry and physics experiments/demonstrations explaining how they work, while basicly putting it all into a show with lots of nice explosions and entertaining things. I would like to do my part on sound. The teacher wants me to rig up a bunch of speakers with small mearors on them and shine lasers off the mearors while music is pumping through the speakers to show that sound is created by vibrating the atoms in air. I will probaly use our smoke machine and cyc to shoot the lasers through and at. My question is, what other demonstrations do you guys think it would be cool to do? My teacher has suggested we use a HUGE slinkey he has and run it from the booth to the stage to demonstrate waves with it, and that should be easy enough to do. He has also suggested shattering glass beakers with the right frequency of sound. I am looking for any other demonstrations that you guys think would be cool and informative, the bigger and more exciting they are the better!