Here’s a newspaper article about a classroom debate on global warming. Class debates are good, I think — they get the students thinking about the evidence and working over how to present it persuasively, although I also think it’s up to the instructor to provide some guidance. Realistically, sixth graders aren’t going to have a good handle on either the facts or the theory, and it’s up to the teacher to give them the battery of data they’re going to use to make their arguments. And sometimes it can go wrong.