19 - Wave Motion and Sound

Abstract

This chapter discusses wave motion and sound. Wave motion is a means of transferring energy from one place to another without the transfer of matter. A wave on the surface of a body of water, for example, can transfer energy over long distances while the particles within the medium, the water, move only by jiggling locally as the overall disturbance, the wave, passes. The media through which waves propagate may be liquids, solids, gases, or even a vacuum in the case of electromagnetic waves. The chapter focuses on mechanical waves that propagate through elastic media composed of particles, which, after having been displaced from their undisturbed equilibrium positions with the passage of a wave, are restored to their equilibrium positions. Physically, any mechanical wave passing through a solid, liquid, or gas may be considered an acoustic wave or a sound wave. To physiologists and psychologists, sound waves are usually considered those waves to which the human ear responds.