[Kat's Mom]

To bounce off Azure's suggestion, a tuning fork can be tons of fun. My kids always enjoy me striking it, getting one of them to hold a full glass of water, and then sticking the tuning fork in to show that the sound waves travel (and splash!) in water very well. It is also fun to experiment with the tuning fork on the end of a plastic cup or the garbage can to show how a megaphone works.