The models created from experimental interpretation are deployed in problems and activities. Another main reason I entered the modeling program is that I knew that my instructional methods would be evaluated through my students' results on the Force Concept Inventory. Now let's consider time management. If I don't use that time properly I lose it, because I don't have them for a whole year. So those 90 minutes can be very difficult to plan.
Some teachers find that they have to switch every twenty minutes.
They have to keep switching topics, otherwise the students can't stay on task. They have a hard time adjusting. It is very difficult for beginning teachers. My colleagues around the nation who are using the modeling method with traditional scheduling encounter some problems too. The class periods are too short.