One of the classes I'm teaching this term meets for two hours. Even though I have taught this class many times before, each time is different and each time involves a lot of preparation before class. As I prepare for each class, I veer between "How am I ever going to fill 2 hours of class time?" and "There is way too much material to cover in two hours."
My uncertainty about how the two hours will be spent stems in part from the fact that, ideally, much of the class involves participation by the students, most of whom are first year students. None of them have taken a seminar-style class before. Therefore, how much participation actually occurs depends a lot on class dynamics and my ability to encourage all the students to say something during class.
I also don't know what will capture the interest of each class. In some classes, the discussion just flows naturally because enough students are interested and ask questions, or I ask them questions that stimulate discussion. In other classes, I end up talking for more time than I want to or should.
It is easy to 'over-prepare' for a shorter class, especially a lecture-format class -- e.g., have in mind other topics to discuss or examples to go over or additional images to show. It is more difficult to do that for a 2-hour class, especially one with a somewhat nebulous format.
Walking to class this morning, I was frantically trying to think of additional topics to bring up should the discussion fall flat, but I needn't have worried. With very few exceptions, the students had a lot of interesting comments and questions, and I was very surprised when I glanced at the clock and saw that only 5 minutes remained of the class (just enough time to talk about the plan for next week).
Next week I will probably have the same pre-class anxieties about time, as the class dynamic is a complex function of the weather, time of year, weekend activities, success/failure of the local sports teams, and perhaps many other variables I do not want to know about, but so far so good.
5 months ago