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Moving toward project based learning—part 1: the frustration

June 27, 2012

This is a post that has been stewing in my mind for months. But it wasn’t until the end of the semester that I really put my finger on what I wanted to say. It started with a moment of awesomeness. M, an outstanding student in my class wanted to show me a particularly unique way he was using to study for our physics final. He’d written one gigantic problem to that used every single standard we’d studied. It involved cheetah sleeping on the edge of a sloped cliff, that suddenly becomes covered in snow, causing it to slide down the cliff, landing on a spring below and much, much more. At first, I thought this was awesome—this student had shown some great creativity in writing his own problem, and pulling together so many ideas that he had learned. His 3 pages of calculations showed real mastery over many of the concepts we had studied, and I was pleased with this students work. But then I got to thinking about what this problem says about our class, my teaching, and the big picture of physics I’ve communicated to my students, and I wasn’t nearly so thrilled.

Here was the culminating moment of my class, the final exam, and the student seemed to equate it with one giant pointless problem sandwich. Sure the problem was fun, but is there any meaning to this work? Does the student even have a basis to judge whether individual parts of the problem make physical sense? Where are the things I thought I cared about, like teaching students to put their physics to use to ask questions about the world around them, and to critically evaluate the answers they find? These failings do not belong to this student—they belong to me.

The focus of my class was problem solving, and my students became expert problem solvers. They improved tremendously at writing out their reasoning, powering through algebra, drawing diagrams and starting with first principles. When I introduced them to goalless problems (something I really love) they began to enjoy those too, and solved for all sorts of things, but what they never did was really interrogate their answers or the reason for doing the work. What’s a reasonable tension in the rope that is attached to a penguin that is attached to a rope that is attached to another penguin and so on, and what’s the point in doing this calculation in the first place?

Sure, I could have picked better problems (that’s the point of the problem database, I want to be able to steal your problems). But most of these problems come from the canon of physics problems, and in general, SBG and the need to craft multiple problems put students in some sort of problem solving loop that asks calculate the (coefficient of friction/spring constant/stretch of spring) for a (block/cart/penguin) on a ramp problem. It’s hard to come up with a lot of problems to use with SBG where each problem has an answer that shows some insight or reveals a deeper meaning.

I think I could have forced more of these discussions in our problem solving and whiteboarding sessions, and I think in a few moments, I did. I also think that some students started to ask questions on their own to gauge the relevance of the problem they were working on or the answer they had computed. But in the end, I made it possible for students to demonstrate mastery of a concept just by solving a problem, and as a result, many students didn’t reach the level of understanding I’d hoped for.

What about lab work? Shouldn’t that be the place where students get beyond problem solving and start to see the “big picture of physics” as developing explanations of the world around them through experiment? Well, yes, and I tried to create labs that followed the modeling approach as authentically as I knew how (I also learned how badly I need to attend a modeling workshop). Students did design their own experiments, and they did have to think carefully about what they were going to measure, how to present their data, and what they could conclude from it. In our whiteboarding sessions, students did construct careful arguments, and combined their findings with classmates’ to tease out and formalize relationships that became the building blocks of our models. But I think some students struggled to follow some of these discussions, and ultimately, found themselves just sitting there waiting for the highlights—the equations that they would need to solve the problems that they would be tested on. Again, I place a lot of blame for this on me—there’s lots more that I could do to make sure that every student is constructing the model in these discussions for himself/herself, and to help students develop understanding by asking questions that push them not just to use the equation, or just to know when the equation is valid, but instead to understand the chain of reasoning that led to that relationship and how it fits into to larger picture of physics.

I don’t think I’m alone in worrying about students becoming expert problem solvers and not much else in science class. Brian Frank recently wrote a post about wanting to include more writing and reasoning in his physics class that has me thinking, and a pretty massive study, the National Assessment of Educational Progress, showed that students are able to find the right answer to many simple scientific tasks, but struggle to explain the reasoning behind those answers (link to full report on science, link to sample science task)—check them out—they are quite fascinating.

So that’s my present frustration—how do I help my students to see physics as more than just problem solving? There was one major bright spot—actually a little bright spots—capstones—that give me an idea for how to move forward in addressing this problem, but I want to save that for a future post.

In my next post, I want to describe try to get away from just describing nebulous feeling of uncomfortableness with my physics teaching and try to pin down exactly what I want my students to do, which I’ve managed to distill down to three words: Be like Rhett.

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