What is the distinction between EM waves and Sound waves. I know that sound is cyclical vibrations in some sort of medium. When the frequency increases, do these vibrations become EM waves? I know that EM waves do not need a physical medium. But they are still energy, and sound is energy. So do they belong on the same diagram showing freqencies? Are sound and EM waves completely seperate things, or are they the same things but at different frequencies? For instance, the frequency of an AC circuit. 60 hz. Does this produce a 60 hz sound wave in the air from the wire vibrating? No it does not, be cause the thing that is oscilating is the potential in the conductor. Is there some crossover point where energy vibrates in the EM spectrum and not in the sound spectrum?