Rarefaction - GCSE Physics Definition

Rarefaction is a term used in physics to describe the part of a longitudinal wave, such as a sound wave, where the particles are spread out, resulting in lower pressure. Sound waves travel through the air as a series of compressions and rarefactions, which means areas where the air particles are pushed together and areas where they are pulled apart. During rarefaction, the particles have more space between them, which contrasts with compression where particles are tightly packed. Understanding rarefaction helps explain how sound waves move through different mediums like air, water, or solids.