In which classes are riddles appropriate?
So far all classes and levels that I've taught have enjoyed riddles.
The class I put the riddles up in these days is a study-hall get help type of class. It's a good way, in my opinion, to start off each class period.
When to use riddles
I put up a new riddle every day. If the student solves the riddle, they get a piece of chocolate - think Hershey's miniatures - (post holiday sales are a great time to refill the bag). Occassionally they'll ask to solve another riddle for a second piece of chocolate - I limit it to two.
Although there's no specific kind of riddle, they like them to not be too hard,
so if the references are too obscure, they don't like that very much.
I've found that the kids generally improve at the riddles if they care enough to pay
any attention to them. I tend to put up easier to middle level difficulty
(at least they way I rank them) because I want it to be a positive
experience for the most part.
There are some kids who never try to solve them.
Some start off saying "I'm terrible at riddles."
And then once they solve one they start to gain more confidence
and stop saying that.