Of late, I have been reading and rereading Arnold Arons' Physics teaching bible of 1990 - "A Guide to Introductory Physics Teaching". From the time of its original printing it has been a physics teacher's best friend. A physics educator reading this gets invaluable insights on not only how students learn Physics but also on what they need to unlearn to gain a deeper conceptual understanding. The book has managed to distill into a few chapters some of the most important ideas that were born out of the pioneering Physics Education researchers.
About thirty years ago, College and University Level Physics textbooks in the United States underwent tremendous changes in style and presentation. I must confess though that I do not have personal experience with them as a student. When I was an undergraduate Physics major in India in the late eighties, we were still using low cost textbooks, mostly written by Indian University professors, printed on cheap paper and heavy black ink. Not to detract from the quality of writing, it was always funny to encounter a perennial topic starter - "Let us consider ..". It did not matter if the topic at hand was from Newtonian mechanics, Optics, Electromagnetism, Modern Physics or Thermodynamics. And we were lucky if we could decipher the markings and finer details of schematic diagrams. Meanwhile textbook content itself always seemed to be a mile wide and an inch deep.
Any how, students like me survived these textbooks and actually learned to learn on our own. At around the same time, an American Physics student could count on the timeless classics "Resnick-Halliday" and "Sears-Zemansky" to present material clearly and more effectively. Yes, they actually had pictures and schematics in color! I realize now that the strength of the "Great American Textbook" sprang from the highly acclaimed PSSC series and the strong research tradition of the universities and colleges.
Yet there were severe problems underlying student learning and understanding. To give an example, Arons describes in his book, testing students (on their Ph. D. qualifiers, no less) on not observing vertical deflection of electrons in the Cathode Ray Tube in the absence of electric and magnetic fields. He was surprised to read the majority of the student responses indicating that they had failed to apply one basic concept of kinematics - objects fall at the same rate independent of their mass; even though they have a minute amount of mass, electrons would still undergo a very small deflection in the vertical direction, behaving like a projectile whose horizontal velocity was very large compared to the initial vertical velocity (zero!). The lack of observation of vertical deflection had everything to do with the very small value of electron flight time in the CRT and nothing to do with their mass.
The book goes on to prescribe techniques for teaching Physics for deeper understanding and offers new insights based on research on how students learn Physics.
Now, I am happy to say that most of the introductory Physics texts have modified their presentaion reflecting the values of Physics Education Research. Textbooks are even more colorful, with photographs, organization of "learning paths" and end of chapter questions and examples more in connection with real world applications.
The laboratory manuals are changing too. Even publications for in-house use are heavy on inquiry based labs; (the lecture classroom meanwhile has become more of a place to facilitate group learning rather than information transmission by the faculty via lecture and demonstrations)
I am excited to be teaching in these times when customization of textbooks is becoming more prevalent; If and when my institution adopts it, it will remove the long standing student complaint of professors making them buy an expensive textbook and then end up using only about half of its content.
Are there really bad Physics textbooks on the market at the present time? Absolutely. I hope to write extensively on this blog about one such book which tried to incorporate all the ideas out of Physics Education Research and then ended up botching the operation.
As they say, the way to hell is paved with good intentions.
