It plays an important role in almost everything that we do in our lives and we take it for granted. Whether it's the sound that the wind makes when it rustles the tree branches or the music coming out of our speakers, all sound is composed of little sound waves that are made by slight vibrations. These slight vibrations in any object move the air particles around the object in an outward motion and cause a sound when these waves hit your eardrums. Sound waves come in many different types, shapes, and sizes but they all share the same principles and characteristics. Sound waves are a part of every noise and they are imperative to sound perception.
A wave of sound can be considered as a disturbance that travels through some material called a medium, transporting energy from one location to another. (Henderson) Such waves that seem to be hooked onto one another in a straight line are characterized as mechanical waves. When the first particle is disturbed it then moves the second particle on the line because they are hooked together and touching. Once the second particle starts moving, the third will be disturbed by the second particle's movement and the fourth particle will be disturbed by the third particle's movement and so on. The vibration will be passed on consecutively and the energy that was first introduced in the first particle will move on and on from particle to particle in that medium.
These mechanical waves can best be described as producing longitudinal waves. In a longitudinal wave, the medium would most commonly be the surrounding air particles that vibrate toward a certain direction. The individual particles of the medium will always move in a direction that is parallel to the direction that the energy is being applied. (Kriz) For instance, if someone is talking to another person, the sound waves produced by the vocal chords will move in a direction in which the person is faced.