The Physics Roundabout
If you’ve ever been in a physics class, at some point you know it’s going to happen. Sometimes it’s once a week– in other classes it’s every single day.
Teacher: “So we see here, there’s a system that looks like this . . .”
Students: Nodding, acknowledging they see what she/he is referring to.
Teacher: “Ok. Now what will happen if I do this?” (Motions like she/he is going to do something to the system but freezes for drama and to prompt some student reactions).
A multiple choice question pops up on the screen, asking for students to make a prediction of what happens next.
Students: Wrestling with what to say/choose, begin working through a mental flowchart; a newly established norm for physics class that defines how they approach answering “simple” conceptual questions:
- “Nope, it can’t be that one, because that’s the obvious answer–that’s too easy to be right.”
- “It could be that answer because it’s the opposite of the obvious answer.”
- “It’s best to choose one of the other choices because by default, the other two are what the teacher expects me to choose based on what we know (or don’t yet know).”
For the sake of the physics education road sign theme lately and keeping things simple, I’m going to call the above logic/graphic the Physics Round-A-Bout (though I know it happens a lot in other disciplines, too). It’s based on every teacher’s desire to surprise or impress upon students something that is unexpected. Let’s face it, for the most part teachers like sharing what they know, and teachers are intrigued by counter-intuitive explanations. This in large part is what is responsible for the physics round-a-bout. But the round-a-bout is also partly derivative of learning theory: by creating a discrepant event, disequilibrium or cognitive dissonance among students, students begin to assimilate the new information until it is accommodated within their world view or mental content. Wait, what? Yeah, sorry about the jargon . . . Those familiar with Piaget’s work, the work of Karplus or Strike and Posner’s conceptual change research may be giving a fist pump right now. For the rest of us, here’s the short of it:
You see something that doesn’t make sense. You are perplexed. So naturally, you try to figure it out. You work at it until you arrive at some kind of explanation that makes sense to you (whether accurate/complete or not)– fitting it in with other related stuff tucked away in the back of your mind (sometimes done consciously, sometimes not). Then you feel at ease, ready to move on to other things.
This works, and it works well. Humans engage in this practice since birth and it plays a significant role in how “science” is carried out everyday. In fact, science education research and practitioners have formalized the process and put it to use. The 3-phase learning cycle, for example, is designed around it (the 5- and 7-phase LCs include assessment and “engaging” elements).
The problem is, when we teachers repeatedly set up lessons or demonstrations to spark interest and get students perplexed or to make predictions, we often do so without first giving them the opportunity to build a knowledge base to adequately tackle the question. So students frequently are not well-equipped to address what’s presented. And they fall victim to this teachers’ traps time after time.
Short version: We teachers routinely set students up to fail in making predictions, and it gets old.
At an AAPT meeting, I recall a presentation on this by Eugenia Etkina. It was some time ago, but it left an impression on me since I’d already begun questioning the “sage on the stage” teaching mode. For further reading on this, this article by Eugenia Etkina on ISLE provides a good background, though the document covers much more than what this post is about. Fast-forwarding to page 26 of the document gets right to the point: repeated conflict, confront and resolve teaching strategies may actually hinder learning. Instead, there is evidence that students may stand a greater chance at remaining tuned in to the content for long term understanding if they are provided with experiences/data to make successful predictions.
When you think about it, it’s pretty obvious: Do you like being accurate or well-informed about what you’re talking about, or do you prefer to always be corrected on your talking points in front of your peers?
So for me, this doesn’t mean “out with all the demonstrations.” It means letting students ask questions and guiding them toward looking in to key factors that will help them make informed predictions. Still show them cool stuff; everyone likes a surprise/change of pace every once in a while. But try giving students the opportunity to see the connections and applications to the material before an eye-catching demo. Engage them with content they can wrestle with and avoid routine magician shows that always have an unexpected result for unsuspecting physics students. Because in the end, it may not end up getting them anywhere but further removed from the discipline.