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How many courses does it take to learn physics?

February 24, 2011

Thanks to a very insightful comment from Heather Dowd, I’ve decided to share a bit about my education as a physics teacher. My background was a bit unusual. I took 19, count em, 19 physics classes at my college. I was seriously only a couple courses shy of taking every undergrad class, and even tossed in a couple of grad school classes for “fun.” 11 classes were required for the major. What in the world would inspire an undergrad to devote 52% of his coursework to physics? That’s a great question I’m still asking myself. It was something l loved, and still love. But at the same time, upon reflection, I think it shows a bit of Stockholm syndrome.

I started taking college level physics at Georgia Tech as a high school student, and so when entered college officially as a freshman, I was able to transfer in a full year of physics and calculus and start off in sophomore classes. This was a terrible idea. Although I had done well at Georgia Tech, and felt I really had learned the material, there were big gaps in my understanding of both physics and math that weren’t helped by jumping into a sophomore modern physics class when I didn’t really understand paricles and waves from first year physics. Unfortunately, this was the story of much of my undergrad career, fascinated by the beauty/coolness/hubris of physics, my choice was always to push on to the next course. At the same time, I found I could see moderate success with out working myself to death, and no one ever asked me to write a paper, which was something that stuck fear into my heart at the time. So physics seemed safe, interesting, and an addiction was fueled.

The real problem was that I never really put in the effort to really learn physics deeply. Instead of mastering Newton’s laws, I jumped to the new shiny thing, Lagrangians in intermediate mechanics. And rather than really figure out what a potential was, I just jumped into Quantum Mechanics and was blown away that I got to play with the Schrodinger Equation, even though I really had no idea of what a Hamiltonian or potential was. This continued on and on, and by the time I’d graduated college, I thought I knew everything about physics, but really I’d just plastered over each misunderstanding with more misunderstanding (and some fancy math symbols \nabla^{2} \phi, anyone?). I discovered this the moment I got in a classroom, and started to try to explain things as simple as Newton’s 3rd law (which is I now know is by no means simple), that I realized there were holes in my understanding big enough to drive a supergiant star through.

Though almost all of the blame for this lies with me, I think there are things my department did that didn’t really help. Principle among this was the curve. I can rarely remember scoring much above 70% on any physics test as an undergrad, yet this was almost always curved to a B or better. And so I implicitly absorbed the message that physics is so hard that no one expects you to get it all, the goal is just to survive. I can remember one professor comparing physics to baseball, where you are an all star if you can bat .400. Sometimes this made me feel like I was hard-core, like a physics marine, but most of the time, it was demoralizing.

Recently, I’ve been watching how Andy Rundquist teaches his intermediate mechanics class, and I’ve come away amazed. Andy’s trying out standards based grading, which tells students in advance what they’ll need to master, and lays out a clear expectation that they can learn every one of the standards. Andy’s doing so much with screencasts, pencasts and flipped classrooms that it’s hard to keep up. But Andy isn’t doing this to just add whiz bang technology to his classroom, he’s doing it to get precise measures of student learning and maximize the class time he spends on learning. I have no doubt that if more of my classes were like Andy’s I would have come away learning much more physics than I did.

But at the same time, I want to give huge credit to my alma mater for teaching me the most important lesson, a love of science. During my time as an undergrad, I was fortunate to meet two nobel prize winners, including Russell Hulse, who blew me away with an incredible talk to the society of physics students about “What to do when Stockholm Calls” that was simply enthralling. I remember going to a colloquium by Brian Greene, way before he became famous and just being wowed to be in the room with such a captivating story teller. Of all these opportunities, the place where I learned the most was the photonics research lab I started working in as a freshman, where my initial role was to find novel ways to short out expensive equipment and then spend hours repairing it since my boss had a great “no worries, you break it, you fix it” philosophy. Later, I got to create my own project, spending tons of time the machine shop building equipment, and in the lab taking and analyzing data, and absorbing some incredible lessons from some fantastically patient grad students and postdocs.

I’ve tried to bring this love of science to my classes and the schools I’ve taught at. When I was a brand new teacher, inspired by Husle, I created a “Nobel Prize of intro physics” for the lab group that earned the best peer reviews from their classmates. I spent hours in the ceramics studio crafting mini Nobel prizes, and even got a colleague to do calligraphy for the certificates, which were presented at an evening dinner. After reading Punished by Rewards I cringe when I think of all the hoopla and anxiety I created to give out three lumps of clay to the students in my class. I still think my intent was clear—my first priority should be get students to develop a love for science, and see it as a human endeavor fraught with failure, so that they will have the motivation and persistance they need to fill in any gaps I might leave in their understanding.

So, I guess I come away from my experience with what is a pollyanishish thought. 19 courses isn’t enough to learn physics, and adding a master’s degree doesn’t really help. All it takes is instilling a love of the subject, and a willingness to embrace failure. It was these habits that helped me to do all the work I needed to do to remediate my understanding of physics—reading Arons late in to the night, listening to difficult feedback from colleagues who witnessed my errors, and learning from these mistakes. And this journey never stops—this blog represents my biggest effort to-date to deepen my understanding both of physics and teaching. I still can’t make a decent explanation of the self-balancing unicycle.

4 Comments leave one →
  1. Jim permalink
    February 24, 2011 2:51 am

    I can identify with much of your post. I feel like I have continuously been trying to “fill in the gaps” since I took my first formal physics course almost twenty years ago.

    You inspired me to count my physics courses. I took the full IB Physics (HL) course in high school, so two years (Mech. and E&M) there. Twelve undergrad physics courses (28 credit hours, about 25% of my BA). Another 36 credit hours of physics in grad school…continuing ed classes and workshops since then, plus five years of teaching physics (which is where you REALLY learn it).

    And I’m still filling in gaps. And what’s worse, now there are things I know I used to know that I now know I don’t know as well as I used to know them!

    • February 24, 2011 6:29 pm

      Thanks Jim, I think you’re right about still filling in gaps—but that’s the ed-jargon crowd calls lifelong learning, right? I guess my question is how to get my students to want to fill in their gaps?

  2. February 24, 2011 9:07 am

    Thanks for the shout out. I know that I didn’t learn most of what I know in 4 years of undergrad and 5 of grad school (though I feel I did learn a lot taking a semester to study for the prelim exams). When I started teaching I found that I would dig into stuff like crazy and I finally started to see the connections among things. I would find myself embarrassed about my lack of understanding things (including embarrassing episodes during job interviews). Now when I teach I think about how I can get my students to get a glimpse of the connections that I now find so powerful. One mantra I have in my teaching is I don’t want students to say “I get that the math is correct but I never would have thought of doing that.” A great recent discussion we’ve had in class is why do we need kinetic energy when we already have momentum to describe motion. I asked the students to explain why we were integrating force times distance and the conversation was off.

    Thanks for yet another great post!

    • February 24, 2011 6:35 pm

      Andy,
      I have two thoughts. For physics majors, getting students to see the connections and think like physcists seems to be the ultimate goal. I’ve often wondered is separating all the subjects into different courses (QM, E&M, Thermo) is the best way to do this. Have you seen the approach Oregon State takes with their Paradigms in Physics program, where students study various paradigms (symmetry, central forces, waves, quantum measurements) and how they intersect with the various physics disciplines? It seems to have a lot of synergy with the six ideas introductory curriculum.

      For most students, who don’t go on to become majors, I struggle more to try to figure out how to teach them to see connections, not just between physics ideas, but in the larger process of science. If you’re never going to study physics again, that’s fine, but I want you to see that the approach to experimentation, questioning and problem solving we took in our class is something you can apply all the time, from when your computer won’t start up to deciding whether radiation treatment is a good course of treatment for a particular cancer.

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