As sound waves cause particles moving through the medium of the mobile medium compression. (Compressions) and expansion (rarefaction) has changed from the normal scenario, see below .
While the sound wave moves through an intermediary, particles of the medium move in an expansion (Compressions) and (Rarefaction) has changed from the normal state. Please see the below scenario
While sound waves moving through the medium, particles of the medium move in a compressed (Compressions) and expand (Rarefaction), a change from normal to see the scenario below