STRATEGIES IN TEACHING PHYSICS

Sergei Skorik

1. Introduction and motivations.

The following short paper is the final project required for the GRSC 850 class "Seminar in college teaching". The seminars of Professor Dembo have provoked me to think about the role of physics teachers and ways of teaching physics. I'd like to share these thoughts with you. The discussion below is based on my seven years of experience as a student and teaching assistant, and on the writings of Kadanoff and Feynman [1,2], two authors who have helped to shape my thinking. My thinking has also been shaped by two transitions in my life: (1) the transition from a large and strong university physics program in Russia, to the program at USC, which, by comparison, is overall small and weak. (2) a transition from the socialist system to the capitalist system. These transitions have given me a perspective on teaching physics that may not be unique, but which is very personal. I love that beautiful and complex intellectual creation called Physics, and that tiny group of people - theoretical physicists - who are interested in the deepest laws and principles of Nature. In the former Soviet Union physicists were not only firmly supported by the government, but were also -- perhaps because they developed nuclear weapons -- included in the elite of the society. The profession of a scientist was prestigious because he was the one who "worked for the prosperity of all," "paved the path for future generations," "extended our outer limits." The Soviet attitude towards the teachers of physics was, therefore, equally positive. Things are different in the U.S., where the profession of physicist is among the lowest-rated. American students are always anxious. They ask, "Why are you teaching us this stuff? How will it help us to survive?" It seems to me that the Business Departments and Schools of Management offer much more practical and straightforward solutions to these questions. C'est la vie. Before proceeding to a deeper analysis, I'd like to apologize for the poor style of English that I use. You see, I am writing such a composition for the first time in my life.

2. Strategies in teaching physics and the role of physics education.

As everywhere, there are two kinds of students in Physics. The first kind are motivated, gifted students whose interest in physics is mature enough. These students do not require much attention. They will worry about their education themselves, and they will take what they need from the teacher without much intervention on his part. They can take a textbook and learn the subject on their own, leaving the professor room to choose some advanced topic and discuss it in class. A professor gets satisfaction from teaching such students, for it is a pleasure to see people who want to learn something from you and who respect your profession. In principle, teachers are pleased to see any previous student who is using his intellect fully and enthusiastically. Unfortunately, there are no such students in the undergraduate division of the USC Physics Department. Therefore, I will not talk about them any more. The second kind of students are those who could not care less about physics, but who are assigned to take some physics classes. These unwilling students are characteristic of USC; 99% of the students whom I have met at USC are among their number. To deal with these students is real torture because of the distance and mutual misunderstanding that remains between the instructor and student. This happens often in undergraduate education, but I think there is a way how to escape it. When a professor or teaching assistant comes in the class for the first time, he should start, not by writing formulas from the first chapter of the textbook on the blackboard, but by talking about the use of his discipline. If an instructor cannot demonstrate the beauty of his discipline and arouse student's interest, it is proper for him to cancel the class. It is useful, of course, to find out what the students' interests are, and why they came to the physics classroom. In other words, the professor must ask himself the question "What for?" as often as students ask it. The professor must be able to show that he offers to students not the encyclopedia of mankind's knowledge, but something that could be implemented after a while in real life. This brings the questions: "what should be the content of an undergraduate physics education? What can physics offer to non-physics majors?" My treatment of these questions has as a subtext the article by Kadanoff, to which I shall be making reference throughout. A good undergraduate education in physics potentially offers the following benefits to the students whose interest in physics is not narrowly professional. Physics teaches that many problems can be well enough formulated so that they have answers. In physics, there is a clear distinction between correct and incorrect. A main goal of any education should be to teach that truth is not relative, to teach integrity. A wise student might recognize that a distinction between right and wrong applies also to other aspects of life. In studying physics we learn that events in the natural world occur through the working out of laws of nature and that many aspects of these laws are accessible to human intelligence. The existence and ubiquity of law is the primary lesson, and the exact subset of laws learned less significant. Most important, though, is that Physics embodies the values embedded in the basic fabric of science itself: curiosity about the world, the belief that problems can often be isolated and understood, the importance of successful predictions, the damning importance of unsuccessful ones. "Problem isolation and prediction form the keystone of all science, indeed of most thoughtful human endeavor, and they appear in their purest form in Physics" [1]. So says Kadanoff, and I want these words to come across loud and clear, because they are the essence of what I have to say. Correspondingly, the weakness of physics as an educational tool is that physics problems are too pure, too clean, and "do not partake of the messinessness of many real world conundrums". So, the strategy and the content of physics education should be the following: rather than asking a student to memorize a formula, one should teach that student to understand how and why it works. Methods are more important to students than are particular laws, and the problems serve as examples to demonstrate how they can be approached and solved. For a non-physicist, physics must not be a collection of laws, but, rather, a set of methods and a concrete practical skill how to approach a problem. The goal of undergraduate physics education shouldn't be narrowly professional: the school should produce people who appreciate the capabilities of science, who can understand at least vaguely the basic ideas, and who can learn for themselves when they need more detail. To teach a student to be curious is more important than to teach him the Maxwell equations, because then he can figure out what these equations are from any physics book. The above statements do not imply, however, that on the undergraduate level, one should, on the whole, give up thinking about the education of professional physicists. In universities with a greater intellectual potential, where there are mature students of the first sort I described earlier, professional physicists can be successfully "cooked". In such universities, mature students who want to quit pure physics must be given the opportunity to switch to other fields where they can fully use the knowledge they have gained.

3. Choosing the appropriate textbook.

There are hundreds of physics textbooks aimed at non-scientists, and more come out every year. One might think that, for non-scientists, one should create a physics textbook with simplified concepts, plenty of pictures, minimal math, and the latest and hottest real-world developments; in this way, one might think, even the most weak student could understand a few laws of Physics. However, there is an alternative to using a dumbed-down toy textbook: "The Feynman Lectures on Physics." It is profound, pedagogical, and not too old. Moreover, unlike other textbooks, it gives the student a "feel" for the subject. In the introduction, Feynman writes [2]: "This two-year course in physics is presented from the point of view that the reader is going to be a physicist. This is not necessarily the case of course, but that is what every professor in every subject assumes!" I like this attitude. Any good textbook should be written by an outstanding specialist in the field who assumes that the reader wants to master in the subject. Otherwise it doesn't make sense. Besides, the material in the textbook should be exposed in a clear way, so that everybody can understand it. Then the interested, mature students in the class can learn as much as they want from the book. Students who do not have the discipline to read the full volume, and are unwilling to follow the path of Feynman's thought, can be directed by the instructor as to what important chapters to read. Also, the lectures should help the student to understand the textbook. Understanding the textbook, by the way, should be one of the motivations for the student to attend lectures. If there are both kinds of students in the class, the professor should teach a course which lets the more advanced sort of student maintain his enthusiasm and which, at the same time, gives the less advanced student the chance to pick up a few basic ideas.

4. Conclusions.

There are two critical points I can make overall. First of all, my attitude towards USC students is not contemptuous. Probably, I don't really give a good idea of how to reach "the second type of student". Even if my ideas are good, but they're really ideals and I am aware of it. How would I put them into practice? I don't know how to answer this question. I guess one should just stand up and do it, to have enthusiasm and some talent, to be original in everything and to do everything with interest. I am talking in this paper about the ideals, the theory, and my purpose was just this. Second, and relatedly, one might think that Feynman is a difficult introductory text. It can be mind- expanding for serious students who are already fully integrated into the basic concepts and mathematics, but it's by no means introductory for the average poorly-prepared US undergraduate or for the non-scientist who wants to learn something about physics. It will take a lot of explanation and hand-holding by the professor to make Feynman comprehensible to these two groups. But maybe the result will worth it.

References:
[1] Leo P. Kadanoff , Physics Today, April 1994.
[2] R.Feynman, Lectures on Physics, vol 1.