Which statement best describes how sound energy travels in a medium as a longitudinal wave?

• A. Sound energy travels through the movement of particles from one place to another without any oscillation.
• B. Sound energy travels only in a vacuum, without the need for a material medium.
• C. Sound energy travels by the oscillation of particles parallel to the direction of wave propagation, causing regions of $\text{compression}$ and $\text{rarefaction}$.
• D. Sound energy travels by the oscillation of particles perpendicular to the direction of wave propagation, forming $\text{crests}$ and $\text{troughs}$.

Answer: (C)

Verified step by step guidance

1. Understand that sound energy travels as a longitudinal wave, which means the particles of the medium oscillate parallel to the direction of wave propagation.
2. Recognize that this oscillation causes alternating regions of compression (where particles are close together) and rarefaction (where particles are spread apart) in the medium.
3. Note that sound cannot travel through a vacuum because it requires a material medium (like air, water, or solids) for the particles to oscillate and transmit energy.
4. Distinguish longitudinal waves from transverse waves, where particles oscillate perpendicular to the direction of wave travel, creating crests and troughs (which is not the case for sound).
5. Conclude that the best description of sound energy traveling in a medium is by the oscillation of particles parallel to the wave direction, producing compressions and rarefactions.