Accidental Modelling

I decided to break my habit of only writing “correct” answers on the board  this September, and try my hand at crafting “generative questions“.  My best shot was “what happens when you push two magnets together?” so that’s what I asked the students on the first day of DC Circuits.  I figured we’d have a good discussion, I’d learn about how they think, I’d get a chance to talk about noticing your thinking, and we’d go back to my lesson plans about atomic structure.

My brand new students responded with basic answers like “attraction” and “repulsion.”  I asked them what they meant exactly.  Then I asked them what they knew about the causes of that.  We had a wide, rambling class discussion about

  • magnets
  • charge
  • atoms
  • lightning
  • whether electrons can turn into protons
  • whether the vacuum of outer space is the same as a vacuum cleaner
  • gravity
  • nuclear fission
  • whether electrons actually have to be considered negative and protons positive, or if it’s just a way to distinguish them that could just as easily have been the other way around

Then I gave them piles of magnets, asked them to test as many of our ideas as they could, and report back.   I wrote down everything they said on the white board and added a question mark to the end of every sentence.  Everything was up for being questioned — even the stuff you memorized from your science class just a few months ago.  (Maybe especially that.)

The questions were so good that the next day, I handed out a typed copy.  I asked everyone to find one piece of info about every question, using books, videos, web pages, or anything else they wanted, as long as they cited their sources.  They had to record the information they found and their thoughts about the information, especially questions, inferences, and anything that seemed contradictory.  I read their work.  It was compelling and detailed.  I wrote back, asking for clarification, pointing out especially logical inferences, and asking whether they considered certain things contradictory.

Since then, we’ve discussed, debated, and tested.  They’ve responded to my comments and I’ve commented on their responses.  The ideas that are supported by several sources and accepted by all groups have become our model of atomic structure. We took that model and tried to figure out what it could tell us about batteries.   We practiced separating “what I think or know” from “what the model implies.”  Every group recorded what they did on white boards, which I “cam-scanned.”  I printed copies for everyone and distributed them.  They keep asking fascinating questions about electricity.  Even beginning to answer the questions will require us to do all the things in the syllabus, at one point or another. I’ll be damned if I’ll be the one to stop them.

Tomorrow I’ll ask everyone to brainstorm what we need to make the model better.  I hope they’ll choose some questions they want to pursue and decide how to test them.

We’re two weeks “behind” and it’s great.  The students are wrestling with the difference between charge, energy, and force.  We’re talking about valid and invalid inferences.  They’re insisting on all the ideas “hanging together” and going back to ones that seem contradictory, disagreeing in respectful ways and backing themselves up by pointing out contradictions or invalid inferences.

Friday we’ll carry out the tests and research they design tomorrow.  Next week, I have no idea what we’ll do.  I didn’t launch us in this direction on purpose, and I don’t know what I’m doing.  I’m losing sleep over this.  I’m worried that they won’t ask questions, or that they won’t talk to each other.  I don’t know how long things will take.  I’m worried that I won’t be able to help them steer, to keep them from experiencing so many dead-ends that they get bored and give up.  Yet every day goes really well.  This might be the best teaching I’ve ever done.  The anticipation feels like crap.  I don’t know how exactly we’re going to get where we’re going.  The execution feels good though, especially when students are asking big questions about why things happen and how we know what we claim we know.  Apparently the path of learning goes through the swamp of confusion for teachers, too.  Which reminds me that this vague sense of nausea and elation is probably how my students feel when I insist that they try things they don’t know how to do.


  1. I’m really identifying with this post- love it! I’m having a lot of the same reaction to my physics class this year as you describe here. It’s very student driven and almost impossible to plan but with a ton of student buy-in. It really is outside my comfort zone but I know better things will happen in this kind of class than if I stuck to some textbook-driven curriculum. Congrats on surviving the scary feeling and diving in!

    • Thanks — and back at you. Funny thing considering your last few posts, lately I’ve found myself thinking, “damn, I wish all my students had blogs.” Next year, I think. (And nice theme, by the way 😉 )

  2. I love the phrase “vague sense of nausea and elation”. That’s exactly how letting go of the reins can feel.

    Can I ask how many students you have in your class? I used to be much more adventurous when my class sizes were smaller, but I’ve retreated into lectures as the number of students in my classes has skyrocketed in the last couple years.

    • Hi Kate, you’re quite right — this process has been facilitated by an unusually small group (12 students). I’m very lucky to have a lot of favourable conditions in place.

      • Wow! Twelve! Color me jealous. This semester, I started out with 49 students in each class. (Fifty is the legal limit of number of people we can put in a classroom. Thank God for the fire marshal.)

        You can do a lot of exciting things with such a small group. It sounds like the semester is off to a great start!

      • Actually me neither– I’m university-level math. That’s why the fire marshal is the only one who has anything to say about how many people we can stuff inside a room. 🙂

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