There are some great sound resources right here. Your Sense of Hearing Great ear info with a complete diagram, fun facts, and links. A humorous chat explains the properties of sound. The characters are fictional, the science is not. Mechanics of Sound Transmission Dry, but direct statements about the properties of sound waves that are important for hearing.
Energy Explains how sound is energy, and introduces harmonics.
Useful for elementary teachers presenting 3rd or 4th grade electricity kits, as well as middle school teachers seeking information about transistors. This site contains limited information and a few diagrams that teachers may want to view, but it is more utilitarian than educational in its language. Vacuum Tube Diodes Brief interactive tutorial about vacuum tube diodes. Simple, competent background information about static electricity. The use of colorful graphics and friendly dialogue is appropriate for teachers as well as their students.