The program and activities must fit the general structure and the constraints of the CPS science class. In the majority of schools we work with, the class period is only 45 minutes. This is a major obstacle for many teachers who want to conduct laboratory investigations in their classes, let alone inquiry-based activities, which necessarily take more time than lectures or the more traditional types of laboratory activities.

In order to address these logistical issues, van activities were developed that could either be completed in a single 45-minute class period or two class periods, could be easily set up and taken down, and address topics in the CPS curriculum. Of course, the pace of the class depends on the particular student population. While some groups will finish an activity in a single class period, others will take two periods and some will need longer than two periods to complete an activity. The activities are designed with natural stopping points so that a teacher can choose to do only the first few parts of an activity. We encourage teachers to follow an instructional pace that is appropriate for their particular students. The emphasis is therefore more on helping students acquire deep understanding rather than helping students simply complete the activity. Figure 2 shows students working through a Physics Van activity in which they explore the properties of a lens.

Figure 2.

Because the program can serve a school no more than once a week, the activities are modular and although many activities build on others, they are for the most part stand-alone units. This is one area in which the Physics Van activities lack the cohesiveness of some of the larger scale professional development programs mentioned earlier.