What is a low-pressure area in a sound wave known as?

A low-pressure area in a sound wave is referred to as a rarefaction. In the context of sound waves, which are longitudinal waves, the wave consists of alternating regions of compression and rarefaction. Compression refers to the areas where particles are packed closely together, resulting in high pressure, while rarefaction is where particles are more spread out, leading to lower pressure.

Understanding rarefaction is essential because it plays a crucial role in how sound propagates through different mediums. For instance, as a sound wave travels, areas of rarefaction and compression move outward from the source of the sound. This oscillation of pressure creates the audible sound that we hear. Recognizing these fundamental concepts helps in grasping more complex acoustics principles and applications.