An independent school in New York City provides an excellent example of a successful application of the Active Physics curriculum, but aspects of Modeling Instruction could have potential to make the course even more dynamic.
Active Physics is a project-based curriculum with a conceptual focus, designed to be used with ninth graders. Active Physics groups concepts by themes, such as "Communication," "Sports," or "Home," in an attempt to make the physics more relevant to students' daily life. The work done in each unit culminates in a "Chapter Challenge," where students must apply their knowledge to solve a real-life problem. One independent school in New York City has been using the Active Physics curriculum since 1994 as the foundation of a physics course for all ninth graders. When I visited this school, students were studying the efficiency of various methods of heating water, and were just about to begin the "Chapter Challenge" of selecting appliances to meet the basic needs of an average family, capable of being powered by wind-generator with an output of only 2400W.
When class began, students were seated in lab groups, discussing a question from their textbook: "Are high-efficiency appliance worth the added cost?" Students' responses reflected a common misconception - conflating the efficiency of an appliance with an assessment of its overall quality: "Well, yeah they're worth it... they're better." "They're more durable, work faster, and just work better in general." When students were asked to present the results of their discussion, only one group in three appreciated the more subtle implications of the concept of efficiency, stating, "A higher efficiency appliance will make up for its cost with less power used over time," but even this group was confused by the difference between the terms "power" and "energy." The stage was set for an inquiry-based activity to root out the would root out these misconceptions and lead students to a more sophisticated understanding of the concepts of energy, power, and efficiency.
Teacher: "Who remembers how we calculate the thermal energy gained by the water?"
Student: "Was that the thing that was 4.18...?"
Teacher: "Yes, we need the specific heat of water. Anything else?"
Over the course of the discussion, each group eventually arrived at calculations that basically agreed with one another, confirming an efficiency of about 10%.
While watching students carry out this activity and discuss the correct method for calculating efficiency, I tried to imagine what the same basic procedure would look like using a whiteboarding approach. Students might start the lab by brainstorming steps they'd take to to collect whatever data they felt were relevant to a calculation of efficiency, then writing these steps on a whiteboard and presenting them to the class for discussion. Once students had carried out these steps with their lab group, they could attempt a calculation of efficiency (again, on a whiteboard), and discuss as a class whether the calculations they'd made were relevant to the central question of the efficiency of appliances. Different groups could even use different methods of heating the water: an immersion heater, a hotplate, a microwave...
I emailed a prominent advocate of Modeling Instruction to ask about crossover between Active Physics and Modeling Instruction, and she told me that "Active Physics and Modeling Instruction don't go well together." Modeling Instruction is about developing basic models for the most fundamental interactions in physics, whereas the projects in Active Physics tend to highlight more complex applications of these concepts: efficiency of electric appliances, acoustic properties of instruments (watch your ears...), how to build a DC motor or generator, etc. Both of these approaches have merit, and it seems to me that there's a lot to be gained in exposing students to aspects of both. That is, a whiteboarding approach might have avoided the more "cookie-cutter" aspects of this particular lab activity on heating water (and probably brought misconceptions to the forefront more effectively), and a project-based "Chapter Challenge" in a Modeling course might give students a better appreciation for how even the simplest models they develop can be applied to their daily life.
In my observations, I've noticed a trend among teachers of Physics First: in the absence of a single universally-accepted ninth grade physics curriculum, teachers tend to pick and choose aspects of various programs that appeal to them. This dynamism is healthy and exciting, but there is something particularly thrilling about the momentum that has been building around Modeling Instruction. A lot of aspects of Modeling just feel like the right way to teach physics: whiteboarding, student-designed experiments, modeling phenomena with multiple representations, and it's tremendous to see the Physics First movement marching forward hand-in-hand with Modeling Instruction. Still, we'd be wise to keep in mind the potential benefits of a diversity of approaches and try to maintain some of the freedom and flexibility that characterizes so many ninth grade physics classrooms.