chapter  6
18 Pages


The circular ripples from a stone splashed into a pond carry the energy of the disturbance through the water surface to the banks. Sound behaves in an analogous way in air except, of course, that the spread is three­ dimensional. When the man shown shouts, the energy from the vibration of his vocal chords is causing sound waves to radiate in the air around him as a series of suc­ cessive, concentric spheres growing in size (6.1). These waves vibrate the ear drum of the listener, producing the subjective sensation we call sound.