Sound Waves

A sound wave is similar in nature to a slinky wave for a variety of reasons.
First, there is a medium which carries the disturbance from one location to another. Typically, this medium is air; though it could be any material such as water or steel. The medium is simply a series of interconnected and interacting particles.
Second, there is an original source of the wave, some vibrating object capable of disturbing the first particle of the medium.
The vibrating object which creates the disturbance could be the vocal chords of a person, the vibrating string and sound board of a guitar or violin, the vibrating tines of a tuning fork, or the vibrating diaphragm of a radio speaker.
Third, the sound wave is transported from one location to another by means of the particle interaction. If the sound wave is moving through air, then as one air particle is displaced from its equilibrium position, it exerts a push or pull on its nearest neighbors, causing them to be displaced from their equilibrium position. This particle interaction continues throughout the entire medium, with each particle interacting and causing a disturbance of its nearest neighbors. Since a sound wave is a disturbance which is transported through a medium via the mechanism of particle interaction, a sound wave is characterized as a mechanical wave.
The creation and propagation of sound waves are often demonstrated in class through the use of a tuning fork. A tuning fork is a metal object consisting of two tines capable of vibrating if struck by a rubber hammer or mallet. As the tines of the tuning forks vibrate back and forth, they begin to disturb surrounding air molecules. These disturbances are passed on to adjacent air molecules by the mechanism of particle interaction. The motion of the disturbance, originating at the tines of the tuning fork and traveling through the medium (in this case, air) is what is referred to as a sound wave.
Sound is a mechanical wave which results from the longitudinal motion of the particles of the medium through which the sound wave is moving. If a sound wave is moving from left to right through air, then particles of air will be displaced both rightward and leftward as the energy of the sound wave passes through it. The motion of the particles parallel (and anti-parallel) to the direction of the energy transport is what characterizes sound as a longitudinal wave.
A vibrating tuning fork is capable of creating such a longitudinal wave. As the tines of the fork vibrate back and forth, they push on neighboring air particles. The forward motion of a tine pushes air molecules horizontally to the right and the backward retraction of the tine creates a low pressure area allowing the air particles to move back to the left. Because of the longitudinal motion of the air particles, there are regions in the air where the air particles are compressed together and other regions where the air particles are spread apart. These regions are known as compressions and rarefactions respectively. The compressions are regions of high air pressure while the rarefactions are regions of low air pressure. The diagram below depicts a sound wave created by a tuning fork and propagated through the air in an open tube. The compressions and rarefactions are labeled.

1  Questions

A sound wave is different than a light wave in that a sound wave is:
  1. produced by an oscillating object and a light wave is not.
  2. not capable of traveling through a vacuum.
  3. not capable of diffracting and a light wave is.
  4. capable of existing with a variety of frequencies and a light wave has a single frequency.
Sound waves can be effectively produced for demonstration in class for demonstration by:
  1. Using a tuning fork
  2. Using a small canon
  3. Yelling at the students
  4. Talking quietly among yourselves
A sound wave is transported from one location to another,
  1. As though by magic
  2. Through particle interaction
  3. By paying close attention to everything Barney says
  4. Air molecules rubbing up against each other
A sound wave is a disturbance which is transported through a medium,
  1. so it's a longitudinal wave
  2. and so it's a longitudinal wave with latitudinal tendencies
  3. and a mechanical wave
  4. and is easy to listen to.
A tuning fork is a metal object consisting of two tines. When the tines of the tuning forks vibrate back and forth, they begin to disturb
  1. Tiny little bits of stuff in the air
  2. AntiThe rubber mallet that started the whole thing
  3. The air molecules surrounding the tines
  4. your parents, and I mean NOW!
A rarefaction
  1. Is a style of hair popular with teenagers
  2. The way some people like their steaks cooked
  3. The areas in a sound wave that have less energy
  4. The areas in a sound ware that have the most energy
Longitudinal means
  1. That you needed to pay attention in Ms. Blairs class
  2. A direction of travel that is also called a straight line
  3. Parallel
  4. Anti-parallel

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On 2 May 2006, 08:51.