Physics First: Of Insight, Pool Balls, Stasis, and the Scientist in the Crib-Lederman Reply

Abstract

Leon Lederman’s much appreciated commentary is 90% excellent. It strongly urges that high-school students study three years of science and learn the process of science as well. I disagree with one major point, however: The traditional order of biology, chemistry, and lastly physics makes much more sense than the reverse order Lederman advocates. Here’s why. ▹Lederman argues that 9th-grade physics would transition into 10th-grade chemistry, which in turn segues into biology, each course building on the previous. I take this to mean that the 11th-grade biology teacher would have to be able to teach the physics of biological processes, presumably including protein synthesis, muscle action, and DNA replication. But isn’t it a bit much to expect high-school biology teachers to cover physics at all, much less something so sophisticated?▹I am hardly the first to point out that students learn slowly and gradually, and that they learn better when starting with the concrete, followed by concepts and analysis. Shouldn’t students know something about the structure and function of DNA and proteins before being given a physics explanation of what holds these macromolecules together and what physically makes them interact as they do in the cell? Teach the biology first, then the physics explanation later. First the phenomenon, then the explanation.▹Biology is more accessible to young people than the conceptually more sophisticated physics. Ninth-grade physics would have to be “baby physics.” Students can understand physics better if they remember a tiny bit of algebra. Learning physics, with its conceptual difficulties, is much more possible in the 11th grade, after students have learned in biology and chemistry what science is like. Being more knowledgeable mathematically will help too. Can we really expect most ninth graders to understand the meaning of an inverse square law—or even mv2/r, or Faraday’s law? Surely trying to teach the physical nature of even the simplest chemical bonds—exclusion principle, wave interference—needs to be done by the physics teacher. And not before students have heard of chemical bonds and what they do. Physics is the most basic of the sciences, even the pinnacle. Physics offers the ultimate explanations of how things work, the explanations most removed from ordinary reality. I emphasize again: first the phenomenon, then the explanation. To teach explanations before students know the phenomena doesn’t make sense. And we should not expect chemistry or biology teachers to teach physics. The final course in the triad, physics, should definitely include physics applied to biology as one of several culminating points. Another might be cosmology. As a footnote, I have team-taught, with chemistry professors, courses for teacher candidates. It’s tough, in part because chemists view the atom very differently than we physicists do. Also, I’d like to emphasize that students generally know much less than we hope they do, even in biology. Thus normal descriptive biology should not be downgraded to totally favor biochemistry. © 2002 American Institute of Physics.