Question

the pattern in the spring toy highlights key features of a longitudinal wave. the areas that are squeezed together are called compressions, and the areas that are stretched apart are called rarefactions. each repeating movement of the wave, such as compression to rarefaction to compression again, is called a wave cycle.
one property of a longitudinal wave is wavelength. just as in a transverse wave, the wavelength of a longitudinal wave is the length of one complete wave cycle. in other words, the wavelength is the distance from compression to compression (or rarefaction to rarefaction).
this model shows the longitudinal wave in the spring toy. label the model.
compression
rarefaction
wavelength

Explanation:

1. Compression: The tightly coiled, squeezed-together sections of the spring match the definition of compressed areas in a longitudinal wave.
2. Rarefaction: The widely spaced, stretched-out sections of the spring fit the definition of rarefactions.
3. Wavelength: The distance from one compression to the next (or one rarefaction to the next) is the length of one full wave cycle, which is the wavelength.

Answer:

• Top left label (tightly coiled section): compression
• Top right label (widely spaced section): rarefaction
• Bottom label (distance between two compressions): wavelength