This is my third year teaching AP Physics. I have a group of students who have already completed and honors physics course during which they learned most of the information needed for AP. Initially, I thought this would be fabulous (and it really is for the most part). The problem is that I have had a difficult time figuring out how to keep the students interested and challenged when they are essentially (from their perspective) learning nothing new.

Then I discovered goal-less problems. (Thanks, Kelly!) For the first day of class, I turned Dan Meyer’s boat in the river video into a goal-less problem and told the kids to represent Dan’s motion going up the down escalator in as many ways as possible. They should use mathematical models, graphs, charts, diagrams, and solve for any and all unknowns they can think of. Initially, there was a lot of “Wait, where’s the rest of the video?” type questions. After some initial confusion and hesitation (I’m pretty sure these kids are NOT used to such open-endedness) they got down to work.

Overall, I am thrilled with how it went. For the first time, I feel like my AP class is going to be much more student-driven. Walking around class, I was able to get a really good gauge of where the kids were and was pleasantly surprised by how much complexity there is underlying what seemed to me like fairly straight-forward (constant velocity) motion. They got into breaking the motion down into x and y component, free-body diagrams, friction, Newton’s 3rd law, etc. This will serve as a great starting-off point for further discussions. My hope is to continue getting them used to applying all types of models to one scenario instead of segregating separate units.

I did forget to start the class by discussing what we can measure, what values we can calculate, etc. They definitely could have benefited from that discussion – there was way too much time wasted trying to figure out what they could calculate and what they could measure and what exactly they were should do (“Do we need exact values on the graphs? Do we have to calculate the speed of the escalator?”) For their first experience with goal-less problems a focused discussion about where they could take this could have gone a long way.

The only problem I ran into today was focus – some groups were great, stayed on task, and really thought about what they knew and how they could represent the motion in new ways. Some groups, however, sketched some qualitative motion graphs and stopped there. I spent a lot of time trying to re-direct them and get them to realize that they had NOT actually written down everything there possibly was to know about the motion. I am not sure what to do about that. Hopefully as the year progresses they’ll realize the benefit to themselves to really think through each problem thoroughly.

The kids get much better at working with goalless problems as they try more of them (well, of course). It helps a lot to have them focus on diagrams (that’s how experts approach problems, after all). Draw as many as you can, and then annotate annotate annotate them. When they see the diagrams as important, the number of things they think to calculate increases a lot. 🙂