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Learning To Be a Better Teacher By Writing

Homer Simpson is not a good role model for teachers.

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.

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6 Responses to “Learning To Be a Better Teacher By Writing”


  1. 1 Laurence Cuffe (@CuffeL) August 19, 2011 at 14:46

    Physics texts are far to long, and loose the plot of the story for new readers. Attitude is important, Feynmans lectures, are good because of the attitude conveyed. Even classical material can be given interest, having run the physics of running past my class I asked them to find the running speed of a giraffe, and evaluate the internet rumor that a giraffe can kick a mans head off.

    I don’t think its quite relevance that captures the student, some times you have to capture their scientific imagination as well.

    • 2 Matthew R. Francis August 19, 2011 at 16:55

      Feynman is great, but his books are impossible for anyone who isn’t already conversant with the science. I think of his lectures as “general physics for grad students” — they’re a wonderful reference, and I refer to them all the time (including in yesterday’s post on the ammonia maser). His spirit, on the other hand, is something I would love to see more of in introductory physics texts.

      I guess “capturing imagination” is what I really mean by relevance. They have to see physics as truly meaningful, and cool, and exciting. If they’re biologists, they have to see how physics is relevant to biology, but also how it’s interesting in its own right. We don’t need every person taking introductory physics to become a physicist, but it would be nice if everyone who takes it recognizes why we love our field.

  2. 3 Laurence Cuffe (@CuffeL) August 19, 2011 at 18:36

    Maybe you are right about Feynman. Your basic point is sound, In the 70’s I choose physics so that I could find out about lasers holograms and black holes. Somehow inclined planes and conservation of energy challenged me to sustain my fascination. Particularly at an introductory level, when you have quite a lot of service teaching (teaching students who will not major in the subject) Its tough, and such thought exercises as “consider a spherical cow” can leave agriculture students deeply confused as to what planet physicists live on.
    The problem I see with specific texts at the moment, which leads to bloat, is too many fatuous illustrations (1) and too many over elaborate problems of the sort which really boil down to “here are two numbers, find the right example in the chapter to copy, and give me the answer.
    (1) Serway and Jewet, 6th edition p276 A worked example:
    illustration: A girl in a red parka standing on ice with an unconscious polar bear on the end of a string.
    This is the illustration to accompany the concept of the center of mass for a system of particles. There are many such examples.


  1. 1 Learning To Be a Better Teacher By Writing « Galileo's Pendulum | My Blog Trackback on August 19, 2011 at 15:46
  2. 2 Why Do I Write? « Galileo's Pendulum Trackback on October 20, 2011 at 21:03
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