Modeling Workshop – Day Eight

The rubber met the road today for four of our groups. This was the first opportunity for groups to try out material they had developed on the rest of us (in student mode) and solicit feedback about it. It was an incredibly insightful day for me and our group didn’t even get to present yet!

The groups that presented today included an underpinnings unit that ran us through a measurement activity, a physics group who had us develop Ohm’s Law and two chemistry groups. Now, I’m unfamiliar with chemistry modeling but I was immediately struck by the notion that we were no longer dealing with things but instead with the idea of things. There were no hydroxide ions in front of us, only a blue liquid, a clear liquid and a sensor that gave us some number. And when learning about reversible reaction rates and equilibrium, the activity actually required us to represent concentration of reactants and products with volume of water in straws. Both activities were well constructed and interesting to me, but the level of abstraction required as a student was significant. According to the teachers, not every activity is as abstract as those today, but when you’re driving principle is that the entire material world is made up of tiny particles, you can’t really avoid it. As a chemistry teacher, it falls on you to construct opportunities for the students to develop this model, and if that fails, you need some means of convincing them. The only reason they have considered this particle model as a possibile explanation of reality is because you suggested it. Contrast this with physics, where students already have a pretty developed set of models to explain the world based on their own observations.

As a physics teacher, I want to bring more of modern physics into my classroom but to do that I have to confront the same challenges that my chemistry colleagues do. How does one tease Placnk’s constant from the light of LEDs? Or the idea of dark matter from galaxy rotation curves? Are high school students cognitively capable of making these connections? I think back to how excited these ideas made me when I discovered them in high school (Yes, I was a geek even then.) and I want to share that excitement with my students. No one thinks physics is cool because of boxes on inclines. It’s cool because it predicts weird things beyond our imagining and then proclaims that they are real. No other high school class can do that. I don’t know how to bridge this gap yet, but I need to figure out how.



  1. I just stumbled on your blog, thanks for the running account. I’m heading to a workshop this coming week, and I’ll be blogging about my experience (newbie workshop). I’ve been using the CPO curriculum for several years now. It teachers photoelectric effect by using LEDs with RGB filters on a phosphorescent pad. Red light, no glow no matter how close the light source is, Blue light glow even when far away from the pad (must create a good way of blocking ambient light).

    1. Scott,

      I’ve seen some great labs for using LEDs to get at the photoelectric effect and the quantum nature of light. But what I’m really wondering is, do students get that the slope of an E vs. f graph is the Planck’s constant and that this determines the size of the packet of energy? I use modeling and much of what we do is have the students assign meaning to the graphical representations. My big concern is that without the background (typically delivered by traditional lecture), the students will not have the ability to make the connections necessary to develop a model of the quantum nature of light. Have you had success with anything like that?

      Thanks for reading and taking the time to comment. I’ll be sure out your account of the workshop.

  2. Brian,
    I really like the LED idea, but I really struggle to get even E&M into my curriculum, so I’m not sure how I could fit in full units on modern topics.
    I also haven’t taught the chem course before, but as I understand it, they do a lot to with manipulatables to try to give the kids some real models for the abstract ideas they are discussing. Chemistry is a tough subject to teach for deep understanding, IMO—it’s too easy for kids just to stay at the plug and chug level.

    1. John,

      I know what you mean about time. This year, I moved our honors class embarrassingly slow. So, maybe teaching actual units on modern topics isn’t the way to get that content into a modeling class. I’m assigning Feynman’s Six Not-So-Easy Pieces for my AP Physics class next year. I’m going to experiment with this as a means of talking about these topics without the students necessarily developing the models themselves. I’m hoping it will still engage them while also injecting some much needed reading into my course.

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