Final answer:
Sound is a longitudinal wave consisting of compressions and rarefactions. A representation of a longitudinal wave includes marking the center of a compression, the center of a rarefaction, and the wavelength, which is the distance between consecutive compressions or rarefactions.
Step-by-step explanation:
Sound is a type of wave that is characterized by being a longitudinal wave. In a longitudinal wave, the disturbances are periodic variations in pressure that are transmitted through fluids like air and water, or solids. For a longitudinal wave, a single wavelength is the distance between two consecutive compressions or rarefactions.
To sketch a longitudinal wave, imagine a series of alternating compressions and rarefactions along a horizontal line. A compression can be represented as a closer grouping of particles, while a rarefaction would show particles spread out. Label the center of one of these compressions as the point where the particles are most closely packed together and label the center of a rarefaction as the point where they are furthest apart. The wavelength (λ) can be denoted as the distance from the center of one compression to the center of the next one.