Teaching Physics through History and History through Physics

by Frederick Gregory (Emeritus Prof. of History of Science, University of Florida) and Peter J. Hirschfeld (Prof. of Physics, University of Florida)

At a moment during a mixed academic social gathering where the conversation turned to the divide between the STEM disciplines and the humanities, the authors, a historian of science and a physicist, chatted about teaching the history of humankind’s ideas about the universe together. At this early stage in the evolution of the history/physics course “The Universe and Humanity’s Place in It,” the bureaucratic and pedagogical hurdles seemed considerable. Problems of cross-listing, allocation of student credit hours, team teaching credit, and questions of how to inspire and motivate a potentially disparate audience of humanities and science majors effectively ended the discussion that evening.

Our dialogue was rekindled, however, by a program sponsored by the local Center for Humanities in the Public Sphere, providing a small amount of funds for team-taught course development between disciplines. The institutional imprimatur of the Center also had the potential virtue of providing some political cover for each of us seeking permission from our respective chairs to teach something outside of the standard curriculum.

In the process of writing the proposal to the Center, we discussed our goals, which eventually crystallized into a course exploring humans’ view of terrestrial and celestial phenomena from ancient to modern times and, in parallel, offering basic explanations of how science views these phenomena today. We hoped that non-scientists, at whom the course was primarily aimed, could appreciate how scientists go about their work today while learning how this method was actually developed. Rather than presenting modern ideas about time, space and the solar system as facts to be memorized and regurgitated, we proposed that the course should expose students to the convoluted path by which these ideas arose, including the many mistakes made by philosophers and scientists along the way.

Showing students that scientists have often changed their views for a variety of reasons (some of which are cultural and not scientific), we hoped they would learn to look at the current consensus as a work in progress that is affected by many factors. By the end, we said, students should not only understand a bit more about how the universe works and have acquired a framework to think about technological aspects of the world around them, but also realize that science is an organic, evolving enterprise rather than a static set of “correct answers.”

Ultimately the class was taught in the Spring semester of 2015 under a course number that had been used by the Department of Physics to teach a traditional “Physics for Poets” course to humanities students, covering much of the usual territory of any introductory physics course, including velocity, acceleration, energy, Newton’s law’s, optics, etc. This forerunner of our course had a laboratory component and was originally designed to be attractive to nonscientists because it helped them satisfy university natural science and lab requirements, without requiring much in the way of mathematics. However, it had devolved over the years into a rather dull course which left students feeling that they had tasted science but not digested much.

In redesigning our new team-taught course, we wanted to retain the laboratory component, both to continue to attract humanities students seeking to fulfill their distribution requirements, and to give a hands-on sense of how scientists, including ancient natural philosophers, had been able to come to remarkable conclusions with a modicum of mathematics and a great deal of ingenuity. For example, we designed a lab where the students determined the circumference of a sphere of styrofoam by measuring the shadow of a toothpick inserted into its surface, thus emulating the essence of the famous measurement of the circumference of the Earth by Eratosthenes around 240 B.C.

The course began with the science of the ancient world, focusing on Aristotle’s hugely influential ideas about both earthly and heavenly motion. In parallel, modern concepts of motion were introduced, deliberately creating a certain cognitive dissonance in the minds of students. They were asked to reason as Aristotle might have regarding, say, falling bodies, and then answer the same question as a modern person might. Similarly, medieval notions of force and impetus were contrasted with Newton’s laws. The modern picture of the solar system was introduced in labs concomitant with discussions of the cosmologies of Ptolemy, Brahe, Copernicus and Kepler. Roughly the second half of the course was devoted to the classical physics of Newton and his successors in the 18th and 19th centuries, and to the revolutions introduced by Einstein and the progenitors of quantum theory. The semester closed with discussions of the expanding universe, big bang, and the discovery of the cosmic microwave background radiation. A full syllabus is available at http://www.phys.ufl.edu/~pjh/teaching/phy1033/1033C2015index.html.

Of course the goals of the physics teacher and the history teacher are not the same. The historian wishes, as much as is possible, to teach students to put themselves into the mindset of people from the past and to expose them to the means by which scholars have attempted to achieve that. Naturally, reading assignments of primary and secondary sources are essential, as are lectures and the occasional use of film or other audio-visual means. The physicist’s goal in the classroom is to help students grasp the principles of physics through lecture, demonstrations, homework problems, and hands-on laboratory experiences. In this class not only did we do all of the above, but we crossed disciplinary boundaries without fanfare. It fell to the physicist to explain medieval critiques of Aristotle’s understanding of motion and to the historian to demonstrate what happens when a magnet is inserted into or withdrawn from a coil of wire whose ends are connected to a small electric bulb.

It quickly became clear that each of us was going to have to make compromises. It was important to the historian in our pair to explain that Sadi Carnot believed that heat was conserved as he came to the realization that to run an engine you need reservoirs with different temperatures. The physicist, however, was quick to assure the students that the present view is that heat is not conserved. While one of us made peace with the practice of correcting historical figures whose reasoning did not mesh with current understanding, the other learned to tolerate explanations of “discarded” science. The difference reflected here ran fairly deep and the students picked up on the historian’s reluctance to regard contemporary conclusions as “right” and the physicist’s impatience with the historian’s eternal suspicion of modern views. We worried that our differences would confuse students, but we found that they enjoyed our questioning each other and encouraged us in our differences.

Courses like this one are rare, first of all because funding is generally hard to come by. Our hope is that the overwhelmingly positive experience we enjoyed is indicative of the general merit of exploring history and physics together. Both of us are convinced that this course made a permanent impression on our students and that it will be among those that they look back upon as one of their most memorable classes, an impression bolstered by final student evaluations.