What is Sound Wave Characteristics?
Sound waves are a special type of wave that the human ear can perceive. Sound waves have special properties that make them unique.
Mechanical Waves
An important property of sound waves is that they are mechanical waves. This means they move through a vehicle. Sound waves can travel through any medium. Normally we hear sound waves traveling through the air, but sound can also travel through water, wood, soil, and many other substances. However, sound cannot travel in a vacuum like in space.
The source of the sound wave is something vibrating. This vibration causes a disturbance of the molecules around the source. The energy of a wave is transferred from one molecule to another in the medium.
Longitudinal Waves
Another characteristic of sound waves is that they are longitudinal. This means that the interference wave propagates in the same direction as the wave. When the molecules vibrate and transfer energy to each other, they create waves that travel in the direction of the vibration.
The longitudinal characteristic of the sound wave can be seen in the figure below. Here you can see how the molecules move from left to right, causing waves and turbulence to move in the same direction. In certain regions of the wave, the molecules group together. This is called compression. In other areas, the molecules spread out. This is called rare.
What is the Wavelength of a Sound Wave?
We have studied how to measure the wavelength of a transverse wave from peak to peak or trough to trough. It’s pretty easy to see by looking at a chart. However, sound waves are different because they are longitudinal waves. To determine the wavelength of a sound wave, you measure from compression to compression or from rare to rare.
Pressure Waves
Sound waves can also be thought of as pressure waves. This is because compressive forces and rare elements move through sound waves of different pressure. Compression is an area of high pressure while rare areas are areas of low pressure.
What is the Amplitude of a Sound Wave?
Sometimes you will see the graph of the sound wave as a sine wave (see below). This is different from the graph of the horizontal wave. The peaks and troughs of this wave represent graphically the change in pressure that occurs in the wave. From this graph we can determine the amplitude of the sound wave. Amplitude is the peak of compression or rarity on the chart.
Intensity of a Sound Wave
Sound waves are sometimes measured by a quantity called intensity. The intensity of the sound wave (I) is equal to the sound power (P) on the surface (A):
I = P/A