Classroom lessons have a specific structure which guides patterns of interaction between teachers and students. The formal structure of the lesson is contrasted to the less formal structure of transitions: the times between the lessons. The informal structure of transitions allows an opportunity for different types of interaction which are discussed in the paper. Observations and interviews with two classroom teachers indicate that teachers are concerned about saving time and maintaining order during transitions. Teachers develop strategies to move their students in an efficient and orderly manner from lesson to lesson. How teachers establish routines and expectations is discussed in terms of how this helps teachers meet their goal of teaching extensive amounts of academic information. (Author/JD)