"I start with a brief explanation of the next concept or topic. I then present the students with a short puzzle or problem incorporating this concept. The students discuss the problem in small groups of 2-4, and then vote using polling hardware or "clickers" similar to TV remotes. After everyone has voted, the results appear on the screen at the front of the class. A well-chosen problem is one for which about 70% of the students get the right answer"
Faculty explains using the 'Peer Instruction' technique promoted by Eric Mazur of Harvard. The technique uses clickers to facilitate active learning in large classes.