


These air pressure changes travel as waves through the air and produce sound. When an object vibrates, it causes slight changes in air pressure. Sound is produced by vibrating objects and reaches the listener's ears as waves in the air or other media.

In either case, it can be hazardous to a person's hearing if the sound is loud and if they are exposed long and often enough. Rock music can be pleasurable sound to one person and an annoying noise to another. The difference between sound and noise depends upon the listener and the circumstances.
