IB Physics C.2.1 Classification of Waves Key Definitions

A compression is a region in a longitudinal wave where the particles of the medium are close together, resulting in a high-pressure area. In sound waves, compressions correspond to regions of increased air density and pressure.

A crest is the highest point of a wave, where the displacement of the medium is at its maximum positive value relative to the equilibrium position. In a transverse wave, crests correspond to peaks in the wave motion.

A rarefaction is a region in a longitudinal wave where the particles of the medium are spread apart, resulting in a low-pressure area. In sound waves, rarefactions correspond to regions of decreased air density and pressure.

A trough is the lowest point of a wave, where the displacement of the medium is at its maximum negative value relative to the equilibrium position. In a transverse wave, troughs correspond to the lowest points in the wave motion.

Waves are disturbances that transfer energy from one place to another without transferring matter.