Human speech is produced by vibrating our vocal cords and transmitting the sound through the air. These vibrations are detected by our ears and interpreted by our brains. Have students relate their experiences. If we could visualize a wave, we could tell a lot about it.
Pure tones have simple shapes.
Scientists use the same principle when they examine our earth. Geological features such as water, rock, sand, and oil are all mediums that are sensitive to sound in different ways. Specially trained scientists are able to help us map the features that are beneath us in the soil. Place the press board on top of the soil. Tap gently on the board and listen for a change in pitch to locate objects.