Sunday, August 3, 2008

Physics (and Astronomy) by Inquiry

This summer, I experienced first-hand the Physics by Inquiry (PbI) curriculum. Here, I give my thoughts on it, and describe a plan to use the PbI astronomy modules in my Astro 101 course.

This summer, I began work in the Master of Science in Science Education (MSSE) program at Montana State University. Two of my on-campus summer courses were out of the Physics by Inquiry curriculum. One course focused on electric circuits, and the other focused on light, color, and geometric optics. Even with my background in physics and astronomy, I learned a great deal of physics in these courses.

Physics by Inquiry (PbI) is the product of decades of research by Lillian McDermott and the Physics Education Group (PEG) at the University of Washington. The curriculum is completely learner-centered, in that there is essentially no lecturing at all. Students work in collaborative groups on observations, experiments and exercises. The activities were designed to help students confront common misconceptions and see that other, more accurate explanations are needed. The activities lead the students to develop accurate and mature scientific models of the phenomenon being studied. For example, in my four-week course, I think I learned more about basic circuits than I did with the more abstract and mathematical approach I had as an undergraduate physics major. The circuits module breaks the topic into two models: current and voltage. By the end of the module, students have two models they can use to analyze any basic situation with circuits (pre-RC circuits).

By the end of the two courses, I had become enamored of the curriculum. I started to wonder why all introductory physics courses aren't using it. The answer, without getting into other, more historical and political, reasons, is logistics. McDermott and the PEG recommend a student-to-teacher ratio of 7:1, so a course with 200 students becomes too unwieldy even for a teacher with two or three TAs. My own courses have no more than 36 students in them, and I would still need a TA or two to help answer student questions and check on groups so that incorrect models and misconceptions don't form.

PbI has two astronomy modules. Astronomy by Sight: The Sun, Moon, and Stars builds models for the path of the Sun (Daily motion, with some seasonal change), phases of the Moon, and daily motion of the stars. Astronomy by Sight: The Earth and Solar System leads into yearly variation of the Sun and stars on the celestial sphere. What I love about the modules is that they are completely based on long-term observations that students make themselves.

Because of the long-term nature of the modules, and the fact that I have no teaching assistants, there is no easy way for me to implement the astronomy curriculum in the lecture sections of my Astro 101 courses. However, my Astro 101 course has a weekly lab associated with it. Because the labs are significantly smaller than the lecture sections, the students/teacher ratio is improved. Lab would be an appropriate venue for the inquiry approach. This fall, I think I am going to experiment with the modules and see how they work with my community college students. My suspicion is that the activities will blend well into the course. With this radical departure from my traditional lab format, I will also change the order of topics in my lectures. Historically, I had always started with naked-eye astronomy, with students doing the lecture tutorials on the celestial sphere first in the semester. With the inquiry modules being worked in lab, I think it will be beneficial to move the celestial sphere discussion to last in the semester, so that students approach the abstract tutorials with models they have built themselves over the course of many weeks.

If any Teaching Astronomy readers have experience with the PbI astronomy modules, please comment here with your insights.

Paul Robinson
Westchester Community College

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