Regular readers of this blog know I’ve been running an occasional series explaining basic physics concepts, starting with simple oscillators (pendulums) and going from there. (I’m not done with oscillators yet, either — I intend to do at least three more on chaotic oscillators, sound waves in solids, and a bit of quantum field theory.) It’s not surprising that a lot of physics is in oscillators — it’s common knowledge, after all — but I started thinking ever more deeply about pedagogy as I wrote these posts.
In nearly every college-level introductory physics textbook I’ve ever seen, the first topics are concepts of motion, without reference to what causes that motion. Essential topics like force, mass, and energy are relegated to later chapters. Even beyond that, textbooks cover pretty much the same topics in nearly the same order, no matter who wrote the book or who published it. As a result, the differences in books are a matter of style, not substance. That isn’t necessarily a problem. However….
Introductory physics textbooks are far too long for a regular two-semester physics course (which is the most that many colleges can offer). They are so large and expensive that students put off or avoid buying them, and they often come with a bundle of “supplementary material”, which is frequently of questionable value. The books only get to “modern” topics (meaning: discoveries between roughly 1900 and 1950) in the last few chapters, which conveys the impression that physics is a dead field. A good teacher can make up for a lot of these deficiencies, of course, but if that professor is teaching in harness with others or has syllabus requirements put upon her by the department (neither of which are unusual circumstances), changing the order of topics, skipping certain things to get to the “modern” section earlier, etc., may not be sanctioned. As a result, a lot of the focus of physics education research has been on technique rather than content. Many of those techniques are very good, and I’ve used many in my classes…but the books are the same books.
As I think about how many ways oscillators enter into physics, I wonder if an introductory physics textbook could use them as the central focus. Many concepts — forces, energy, momentum, topics in quantum physics — could be introduced through oscillators. I’m not married to the particular idea, and I’m unlikely to write an introductory physics textbook any time soon, but the general plan is one worth considering:
- We should introduce motion alongside the causes of that motion.
- We should start bringing in quantum mechanics, relativity, and truly modern research (e.g. chaos theory and biophysics) as early as possible.
- Whether or not oscillators are the central idea of the book, we should emphasize their centrality to physics (and engineering and chemistry and biology) rather than putting them in their own chapter and never bringing them up again.
- We need to make sure above all that the students understand the relevance of what they are studying! Students are students: they will tend to care more about passing exams and getting good grades than understanding the material, but we can certainly do better in terms of inspiration.
Everything I write here is based on mistakes I’ve made from lack of imagination on my part, so don’t think I’m standing here feeling superior to everyone else. Writing about basic physics concepts outside of a classroom context has helped me clarify my thinking on the subject. I may never teach again (in a classroom setting, that is — my friends and family will tell you that I go into “teacher mode” at random intervals, and a lot of this blog is obviously teacherly), but just as teaching someone else a concept is a good way to learn it yourself, writing is helping me to think more specifically about how to fix the problems of physics education.
It makes me wish I had started doing it earlier.