How do molecules behave when a sound wave travels through a medium?

When a sound wave travels through a medium, molecules in that medium behave in a specific way that allows the sound wave to propagate. They move backwards and forwards in the same direction as the wave travels. This motion is a result of the pressure changes created by the sound wave, which compresses and rarefies the medium.

As the sound wave passes, molecules are pushed closer together during the compression phase and then allowed to return to their original position during the rarefaction phase. This back-and-forth movement transmits the energy of the sound wave through the medium. Therefore, the correct understanding of molecular behavior during the transmission of sound is that they oscillate in line with the direction of the wave's movement, helping it to travel efficiently.