Rock is a louder and more strong and fierce way of music. You can do heavy rock(medal) witch is a high pitched loud screaachty sound in music. If you heve ever heard the song beverly hills by Wiezer you know that rock is not always so annoyingly loud, weezer has kind of a medium soft sound. But in the middle of the song they suprise you with some temporary beat drums.
Disco is not used as often anymore but back in the day people discoed all the time, they did the diangnal finger movment thing and the duck and more. They had afros and hippi doos. They were rainbow colored clothes with a cloth holding up there afro. And now they act like afros are only for colored ppl. Cause there are wrap singers like Afro man and the Afro gangstas and then pimp afros.