We owe our students the opportunity to reach that level of understanding by explaining concepts to their peers. Research on peer tutor-ing, for example, suggests that tutors benefit at least as much as tutees. Putting this principle into play is not a trivial effort. Arranging for effective group work takes serious planning. We have a number of resources on the topic at the Center for Teaching.
Good practice uses active learning techniques.
Students who arrive in the classroom, open the tops of their skulls, and passively wait for knowledge to be poured in will surely be disappointed. To belabor the metaphor almost beyond reason, most of it will spill right out. Our job, then, is to create environments in which students can work, and work hard, at learning. In planning a class session, I think it is much more important to think about what my students will be doing during the session than what I will be doing. Good practice gives prompt feedback.