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.
wavelength
compression
rarefaction

Explanation:

1. The squeezed-together coil sections match the definition of compressions.
2. The stretched-apart coil sections match the definition of rarefactions.
3. The distance between two corresponding points (like compression to compression) is the wavelength, which is the span of one full wave cycle.

Answer:

• Top left label (pointing to stretched coils): rarefaction
• Top right label (pointing to stretched coils): rarefaction
• Bottom label (spanning from one compressed section to the next compressed section): wavelength

Note: The squeezed-together coil sections between the rarefactions are compressions, corresponding to the definition provided.