Formation of Compression And Rarefactions
A longitudinal wave consists of successive compression and rarefaction that is formed due to continuous to and fro motion of a vibrating object. As an object vibrates back and forth, it pushes on neighboring air particles. The forward motion pushes air molecules horizontally to the right and the backward retraction 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. These regions are referred to as compressions and rarefactions respectively.
What Is Compression?
A compression is a region in a longitudinal wave in which particles of the medium are closer to one another than they normally are, and there is a momentary reduction in volume of the medium. It is a region of high pressure and high density.
Example:
When a vibrating object moves forward in air as medium, it pushes and compresses the air in front of it creating a region of high pressure. This region is referred to as a compression.
Facts About Compression
- A compression is a region in a longitudinal wave where the particles are closest together.
- A compression is a region of high pressure and high density.
- In the compression, there is temporary decrease in volume of the medium and increase in density.
- The distance between the particles in compression is less than the normal distance.
- The center of compression is the position of maximum pressure and maximum density.
What Is Rarefaction?
A rarefaction is a region in a longitudinal wave in which the particles of the medium are further apart than normal and there is a momentary increase in the volume of the medium. It is a region of low pressure and low density.
Example:
When a vibrating object moves backward in air as medium, it creates a region of low pressure. This region is referred to as a rarefaction.
Facts About Rarefaction
- A rarefaction is a region in a longitudinal wave where the particles are furthest apart.
- A rarefaction is a region of low pressure and low density.
- In the rarefaction, there is temporary increase in volume of the medium and decrease in density.
- The distance between the particles in the rarefaction is greater than the normal distance.
- The centre of rarefaction is a position of minimum temperature and minimum density.
Also Read: Difference Between Sound And Light Waves
Difference Between Compression And Rarefaction In Tabular Form
BASIS OF COMPARISON | COMPRESSION | RAREFACTION |
Description | A compression is a region in a longitudinal wave where the particles are closest together. | A rarefaction is a region in a longitudinal wave where the particles are furthest apart. |
Nature | A compression is a region of high pressure and high density. | A rarefaction is a region of low pressure and low density. |
Behavior Of Density & Volume | In the compression, there is temporary decrease in volume of the medium and increase in density. | In the rarefaction, there is temporary increase in volume of the medium and decrease in density. |
Distance Between Particles | The distance between the particles in compression is less than the normal distance. | The distance between the particles in the rarefaction is greater than the normal distance. |
Center Position | The center of compression is the position of maximum pressure and maximum density. | The centre of rarefaction is a position of minimum temperature and minimum density. |