Sound Is a Wave (it needs a medium) Transverse vs. Longitudinal Waves medium http://dictionary.reference.com/search?q=medium
- An intervening substance through which something else is transmitted or carried on.
- move in the same direction as the wave between 0° and 180° to the direction of the wave.
A sound wave is a longitudinal wave
- move at right angles to the direction of the wave.
Water is a transverse wave
Transverse Wave and Longitudinal Waves
Neither the molecules in the air or those in water actually move along with the wave. Air and water are simply a medium for the wave to pass through.