The particles in sound waves move back and forth in place. This is called vibrational motion.

Here's why:

* Sound waves are longitudinal waves: This means the particles in the medium (like air) vibrate parallel to the direction the wave travels.

* No net movement of matter: The particles themselves don't travel long distances; they just oscillate around their equilibrium positions.

Think of it like a slinky: when you push one end, the coils compress and then expand, creating a wave that travels down the slinky. The coils themselves don't move far, they just vibrate back and forth.