The current challenge: introductory physics

The power of physics, as a discipline, derives from the fact that very general theories can be expressed mathematically and the experimental precepts can be reduced to number forms. Thus, physics is a quantitative discipline and when treated quantitatively, the ideas of physics can be understood and appreciated only by those who have devoted the time required to learn the language of mathematics.

But the power of physics goes far beyond the discipline itself. To be sure, the ideas and concepts of physics find their meaning in the give-and-take 1 between theory and experiment, but this physical meaning is merely the beginning. The meaning derived from physics informs the intellect about the most basic features of the universe; it teaches us about mass-energy that takes the forms of an atom, a protein, an oak leaf, and a child; it shapes the human imagination and finds expression in art, literature, and music; it inspires habits of mind which establish the tone, the character of human culture.

The authority of physics and the influence it has on human thought and behavior places a burden of responsibility on physicists; the responsibility of communicating the ideas and concepts of physics in a language other than that of mathematics and to inform non-scientists about their world. I fear physicists are falling short of meeting this responsibility.

During the 20th century, there have been fundamental changes in the ways physicists think about the phenomena of nature. The theory of relativity and quantum mechanics have cast the universe and the processes within it in new light. Yet, students who take introductory physics courses are unlikely to learn anything about either the new physics itself or the new perspectives prompted by modern physics. This is where physicists have failed.

The absence of modern physics in our introductory courses is a measure of our failure... on two levels. The basic content of introductory physics has remained essentially the same for decades. Oh yes, we no longer dwell on pulleys and mechanical advantage and we now teach statics as a part of dynamics; however, the fact remains that the content of our courses is, as it has been for over a century, mechanics, heat and thermodynamics, electricity and magnetism, and optics. Greatgrandparents and grandparents and parents took, in this basic sense, the same physics course as contemporary students are now taking.

Contrast introductory textbooks of physics, chemistry, and biology. In both chemistry and biology, textbooks have undergone drastic and dramatic changes in the last twenty-five years. Students of chemistry are taught the structure of atoms in terms of quantum mechanics and students of biology are taught the molecular basis of living organisms. New editions of standard introductory textbooks in both chemistry and biology contain new information, information that was not in the last edition. Chemistry and biology are dynamic, developing subjects and this dynamic is reflected in their introductory textbooks. By contrast, physics textbooks are staid and predictable. Later editions differ from earlier editions only superficially: the order of the end-of-chapter problems, the numbers used in the problems, the ordering of topics, etc. No new information appears in a new edition of a physics textbook.

The content of introductory physics textbooks is static and, I fear, the courses based upon them are static as well. The vitality and the spirit that come to a subject when new ideas and new information are integrated into it are missing from physics. I suggest that the small number of students who elect to take physics is directly related to the static, moribund content of our introductory courses. This is the first level of our failure: the vast majority of students eschew the physics classroom. The second level of our failure is that students who do take introductory physics learn nothing about ideas that inspire contemporary physicists.

The tragedy of this failure to bring modern physics into our introductory courses is that the ideas of relativity and quantum mechanics (to say nothing of applications of these great theories) are exciting, provocative, and pregnant with implications for human thought.

The ideas of modern physics could revitalize the introductory physics course and, in the process, revitalize departments of physics. The audience interested in the ideas of physics would expand, conversation about the ideas of physics would be heard more frequently, and students would be more likely to enrol in physics.

Recently, I.I. Rabi has written, “I feel my generation and the current generation have not devoted the time and profound effort to make the extraordinary phenomena of relativity and quantum mechanics accessible to the intelligent, educated person. I am sure it can be done because that's the way I understand it.” Rabi's words are both an indictment and a challenge. We deserve the indictment; we should rise to the challenge.