S _ _ _ _ waves travel.

Describes how high or low a sound is. ( loud , pitch)

M_ _ _ _ _ vibrates.

A movement back and forth. (vibration, wave)

as the bell rings, its vibrations result in spaces where air particles are squeezed together and spaces where air particles are spread apart. This movement of particles makes a kind of wave called a c _ _ _ _ _ _ _ _ _ _ w _ _ _

B _ _ _ _ hears sound.