I suggest a book by Marilyn Stewart called Thinking Through Aesthetics.
It give lots of ideas about questions to be posed to students. These
questions could be used as a start for an art debate. I remember her
posing a question concerning originality. What if someone invented a
device that could replicate almost anything ? (like on star trek) Then
you could make 10,000 replicas of the Mona Lisa. No one could distinguish
any of these from the original. Or make a million replicas and sell them
at Target for $19.95. Is the Mona Lisa still an important creation ?
This sort of question could start an interesting debate.
Woody, Retired in Albuquerque