rarefasjon

Rarefaction refers to the reduction in density of a substance, typically a gas. It occurs when the number of particles within a given volume decreases, leading to lower pressure. This phenomenon is commonly observed in acoustics, where it represents the portion of a sound wave where particles are spread apart. In this part of the wave, the pressure is lower than the ambient pressure.

Rarefaction is the opposite of compression, which is the part of a sound wave where particles are squeezed together, resulting in higher pressure. Sound waves are characterized by alternating regions of compression and rarefaction. These pressure variations travel through a medium, allowing sound to propagate.

In physical terms, rarefaction can be caused by various factors. For gases, it can happen when a volume expands, allowing the gas molecules to spread out. This is seen in the expansion of gases in engines or in atmospheric phenomena. In the context of sound, the vibration of a source, such as a speaker cone or a vocal cord, creates these alternating compressions and rarefactions in the surrounding air. The speed at which these waves travel depends on the properties of the medium.