PBL: From Tinkering to Thinking
It’s easy to think that kids are learning all kinds of science when they are incredibly engaged with building their solar ovens. It sure looks that way. But turns out, not so much. When Lynn Barakos from Lawrence Hall of Science came in to observe and listen to students, she found almost no discussion of light and optics concepts as students were building, testing and refining their solar ovens. They did show some signs of applying concepts such as reflection and ‘concentrating light’ in their journals. But there was quite a bit of random tinkering with kids re-positioning parts of the oven without discussion. And a little evidence of boys being dismissive of ideas from girls. (This is something I want to have an outside observer track for me as I think I’m observing this quite often.)
Part of PBL is going into and out of high level thinking and mastery of concepts. It’s useful to know that we need to plan projects carefully to make sure students really are learning science and are not just playing around. It’s a little frustrating because we did teach light and optics concepts immediately prior to having students design their solar ovens. There’s the rub – ‘covering’ concepts is not the same as having students integrate those concepts into their understanding of the world.
I’m hopeful that by following up, we can use their experiences with trial and error to show how useful it could be to use scientific concepts when designing solar ovens and other engineering projects. Engineering – the application of scientific principles to solve problems for people.
Next on the menu, we are having a carefully designed solar oven competition, set up so that the ‘prize’ is just the attention, and not grades to make it a fun competition that won’t ruin a middle schoolers’ day.
Then they will consider the common features of successful ovens, and why those features may have helped. It’s only when science concepts could be really useful that it might be worth dragging out some heavy-duty thinking. I mean, why think if you can just mess about with your friends and some foil? (Had students making little ear pieces with foil, wrapping themselves in mylar survival blankets – whoa, makes you feel hot, why is that? But nothing too serious and definitely entertaining.)
After that, students will co-construct how a solar oven works with me guiding the physics and diagraming of a kit solar oven on giant whiteboards to facilitate discussion.
They then explain why their own did so well, or how theirs could be improved with some coaching as I circulate.
Finally, there is an assessment where they have to diagram and explain a solar oven winner. They know exactly what the assessment will be except for which solar oven design they will have to explain.
It sure takes a long time compared to the traditional covering light and optics with about 3 labs. Will it result in better long-term learning? I guess I’m persuading myself to include a couple of questions in an end-of-year survey. I really think it will though. The excitement of building these ovens has certainly been teaching students about how to work in groups, how to learn from temperature data, about other countries that could use solar ovens, and of course how to use duct tape and foil in a million ways. The true essence of PBL right there 🙂