President's Commentary (January)

President’s Commentary
Harvey S. Leff
January 15, 2008
As I near completion of my term as AAPT President and prepare for a year serving as Past President, I've been ruminating on my career as a physics teacher. I have no reason to believe that anyone is interested in my own personal history. On the other hand, my long years of experience have taught me some lessons that might be useful to other teachers.
I have no recollection of science exposure prior to my high school days. I do recall being fascinated by my high school physical science course because it dealt with familiar things such as weather and temperature in ways that I did not know existed. In contrast, I found my subsequent physics course less than fascinating, with its initial focus on levers, motion, and forces. The teacher tended to face the chalk board as he talked—actually, it was more of a mumble. Although I knew little about teaching then, it was clear that Mr. B. was not doing it well.

We also studied electricity and each student was asked to make an electric motor. We had not studied the physics needed to understandhow a motor works, and I simply searched for a book containing a recipe for constructing a motor. I bought wire at a hardware store, borrowed some magnets, gathered miscellaneous parts from around my house, carefully followed the directions, and put it all together. In retrospect, my motor was so large and friction laden, that the armature couldn't possibly have turned when connected to one or two D batteries. Indeed, it did notwork. I fearfully expected to get a failing grade on this project when I brought the motor to class. I explained to Mr. B. how I had followed the recipe, but could not get the motor to work. I had even tried using five batteries in series to see if that would work. But no go. Mr. B. examined the motor and said, "Well, let's just see," and proceeded to connect the motor to a 12-volt car battery. I was amazed to see the armature immediately start whirling at high speed. Mr. B. gave me a high grade for that project, which not only relieved me, but really made me hungry to learn about electromagnetism in college. Remarkably, I still remember my motor project more than 50 years later! So although Mr. B.'s lectures were not very helpful, the motor project he assigned had a lasting impact on me.

Lesson #1: If you want students to remember your course, have them construct something or do an independent project, preferably hands on, that requires a significant commitment of time and energy.

After high school, I moved from Chicago to Los Angeles and enrolled in a community college where I studied physics and introductory calculus during the first semester. I always loved math and the calculus was a breeze. But the physics instructor's problem sheets were much tougher than those in our Sears and Zemansky textbook, and posed quite a challenge. The teacher was far from inspirational, and I recall the course as being an enormous amount of work, but very little fun. It was largely perspiration, with very little inspiration. I never thought I'd end up majoring in physics.

I decided to return to Chicago. Suffering from a massive dose of naiveté and ignorance, I had no idea what major to declare. Because I had always enjoyed math and also really liked high school chemistry, a friend suggested that I major in chemical engineering. On the basis of that miniscule information, I decided to do just that.

Lesson #2: Students often choose their majors in college with insufficient information. Teachers should ask students how they have chosen (or plan to choose) a major, what they're good at, and what they enjoy the most. Students should be aware that their choices could shape how they will be spending 40 or more hours weekly for the next 50 years or so. This usually gets their attention.

In Chicago, I continued with calculus, but did not take physics for a year. When I attempted to register in the second physics course at the Illinois Institute of Technology, I was told to retake the introductory class because it covered both mechanics and heat, whereas my previous course was solely on mechanics. Retaking introductory physics turned out to change the course of my life. This was because the teacher, Robert Estin, was a human dynamo whose love for physics was abundantly clear and contagious. Although he used no modern interactive techniques to supplement his lectures, his style inspiredme to learn. Coupled with my prior study of mechanics, this inspirationled me to achieve the highest grade in the class. I enjoyed that class so much that I decided to change my major to physics.

Lesson #3: Learning is perhaps 90% perspiration and 10% inspiration, and the former is more likely to occur when the latter exists. An effective teacher exudes a passion for his/her subject, and inspires and guides students to do their best. This can have profound effects on student learning.

When I told my father about my decision to major in physics, he advised against it because he thought physics was "too difficult." Fortunately, this was one time that I shunned his advice. In fact, one of the reasons I loved (and still love) physics is that it offers continual challenge, regardless of how much of it you learn. The fact that physics was "too difficult" was a reason to choose it as a major, rather than a reason to reject it! Fortunately, my decision was a good one, which I am very glad I made. I enjoyed my undergraduate studies in physics immensely.

As I neared graduation, I was unsure what to do next. The department chair advised me to go to graduate school to learn more physics. My extreme naiveté led me to wonder why I would do that. After all, I had spent several years studying classical and modern physics, and thought there wasn't much more to learn! This was a good example of the adage that Education teaches you what you do not know.I followed the chair's advice and applied to several graduate schools, in the Chicago area and elsewhere. Almost all the schools sent me large envelopes with application materials, and I proceeded to complete and return these. The one exception was Northwestern University. I received a phone call from the secretary of the Northwestern physics department, inviting me to an interview with the department chair, Professor Max Dresden.

I recall walking into his large office and seeing him with a desk full of papers on which there were hand-written, complicated looking equations. I later learned that he was preparing notes on quantum field theory. Professor Dresden was an intense man, with penetrating eyes and an ultra quick mind. I was immediately impressed by his demeanor. He asked me a set of questions, which I answered as well as I could. He listened carefully, and surprised me by saying that I would be accepted to graduate school in physics at Northwestern University. He promised me paid work as a research assistant in Professor Edson Peck's optical interferometry laboratory. I was aware of Professor Peck's textbook, Electricity and Magnetism,and was eager to work with him. My exhilarating meeting with Max Dresden convinced me to attend Northwestern University.

I became a teaching assistant, and underwent a short course on how to be a good teacher. The professor of this course was Clarence J. Overbeck, an obviously highly dedicated teacher. I learned some useful pointers in that short course, at least one of which has stayed with me for 48 years, namely,

Lesson #4: Never embarrass a student in the classroom.

That short course and many years of evaluating the teaching of college faculty leads me to another lesson.

Lesson #5: Every graduate teaching assistant and more generally, every physics teacher should undergo instruction on how to teach prior to teaching a class.

In 2007, while examining AAPT's photo gallery of presidents at the American Center for Physics, I was surprised and delighted to find a photo of Clarence J. Overbeck. I learned that he served as AAPT president in 1958, just one year before he taught me how to teach. What a story. An AAPT president teaches a student how to teach, and that student later becomes president of AAPT!

During my first year in graduate school, I took an advanced laboratory course, classical mechanics, quantum mechanics, and statistical mechanics. The latter was taught by Arnold J. F. Siegert, a student of Werner Heisenberg. Siegert was extraordinarily knowledgeable and a person who lectured at a steady pace that seemed too slow during the easier material and too fast during the more difficult parts. But as with Robert Estin and Max Dresden, he inspiredme to develop an understanding of the subject, both its philosophy and mathematics. I wanted Professor Siegert to supervise my Ph.D. work in statistical mechanics, but he was about to embark on a two-year leave of absence.

I had heard that Max Dresden did his Ph.D. work in statistical mechanics, and asked him if he would accept me as a student. He said yes, but informed me that he would be leaving Northwestern to take a position at the University of Iowa. If I moved to Iowa City, I could work with him. This double exit by statistical mechanics people illustrated to me the probabilistic nature of things: even remarkably unlikely, but not impossible, events have nonzero probabilities!

My wife Ellen and I decided to move to Iowa, and my Ph.D. mentor there was Max Dresden. He was a student of George Uhlenbeck, who, with Samuel Goudsmit, introduced the concept of electron spin in 1926. Uhlenbeck was a student of Paul Ehrenfest, who was a student of none other than Ludwig Boltzmann. What a scientific lineage this was!

Max Dresden was a first-rate lecturer, who made his subject seem easier than it really was. As with my former teachers, Robert Estin and Arnold Siegert, Max inspiredme to dig in, fill in the details, and learn what he was teaching. As a doctoral advisor, he would point me in a direction, and ask me to research it and report back on what further research could be done. This was exasperating at first, because to a fledgling learner it is typically not obvious how to extend what was just learned. I did this with several different topics, the last of which led me to some promising paths, and ultimately a successful thesis.

I would meet with Max Dresden weekly and report my progress or lack thereof. Often, when I was stuck, talking with him would somehow give me renewed energy—even if he provided no substantive help. I never understood how or why, but I certainly appreciated this phenomenon. In retrospect, I believe it was inspirationfrom a man whom I deeply respected. Max Dresden sometimes deviated from physics and shared his life philosophy. When Ellen gave birth to our first child, he told me that the two greatest traumas in a man's life were the birth of his first child and the death of a parent. I found the former to be accurate at the time, and the latter to be right on target when my father died five years later.

Lesson #6: A good mentor provides students with inspiration, guidance, wisdom, and a touch of humanity.

I will close this commentary with lessons learned through my association with AAPT. Although I joined AAPT in the 1960's, my involvement was for almost 20 years solely through reading and writing articles for the American Journal of Physics. In 1983, I joined the Southern California section (SCAAPT). I enjoyed its meetings so much, I decided to attend a national summer meeting, and was immediately "hooked." I have attended the vast majority of summer and winter meetings ever since. At these meetings, I learned much about teaching, presented contributed talks, and developed a network of friends.

At one SCAAPT meeting, I won as a door prize a copy of Eric Mazur's Peer Instruction,which had recently been published. I recall that Ellen picked me up after that meeting and we drove directly to a pizza restaurant to order a pizza for dinner. In the 20 minutes that it took to prepare and bake that pizza, I read enough of Mazur's book to become inspired with the relatively simple, but very powerful teaching approach he espoused. Soon thereafter, I began to introduce concept tests into my lectures. I also decided to learn more about what had been discovered by physics education researchers on what "works." A student, Hany Tawadrous, who planned to become a high school physics teacher, did a senior thesis in PER with me, with an emphasis on peer instruction.

Prior to my involvement with AAPT, I had based my teaching style on the styles of Robert Estin, Arnold Siegert, and Max Dresden, because those styles worked well for me. I know they were all great teachers for me. However, learning about what education researchers have observed—coupled with my own less than satisfactory results teaching general physics—made me realize that what worked for me and many physicists when we were students does not necessarily work for the vast majority of students. They take physics either to fulfill a requirement or simply because of curiosity. I went from thinking I knew a lot about teaching to the realization that we are only scratching the surface of understanding how physics can be most effectively taught to students with varying interests and abilities.

Lesson #7: Teaching requires a linkage, a connection, between teacher and students that provides effective guidance and practice, and timely feedback to correct misunderstandings. For some students, sufficient linkage can be achieved via inspirational lectures, well-written textbooks, well-constructed homework problems, challenging laboratory exercises, and instructor availability during office hours. For others, interactive techniques such as Peer Instruction, Cooperative Problem Solving, Physics By Inquiry, Workshop Physics, RealTime Physics, The Physics Studio, Just In Time Teaching, Interactive Lecture Demos, and the like can be more effective.

Finally, here is perhaps the most important lesson of all.

Lesson #8: Without AAPT, its journals, meetings, special topics conferences, and other opportunities for physics teachers to share their knowledge, we physics teachers would be much more poorly informed and less able to serve our students well.

Long live AAPT!