Weekly Physics Challenges

One of the new routines I started this year in support of my self-directed classroom (students are working at their own pace and choosing their own path through a set of learning resources) is introducing a weekly physics challenge problem.

The idea came out of two goals I've had: 1) to incorporate more higher-level challenges to students in general, to support deep thinking and curiosity, and 2) providing interesting discussion fodder that allows us to "sneak review" some of the content we are learning without simply rehashing or defaulting to me reteaching stuff they "should have" gotten themselves.

After the first week I'm pretty jazzed about how my first challenge addressed both goals (and number 2 especially more than I'd expected). I doubt every week will be quite as deep and stimulating, but I'm happy to know it isn't quite as challenging for me the teacher to set up as I thought it might be!

The week works like this:

Monday - introduce challenge and give them some initial individual/table think time.

Friday - class begins with some discussion protocol about the challenge in partners or small groups, followed by a whole class debrief where we collectively construct a "solution." (The protocol was what I call intentional conversations, as I'm working now to establish this as an ongoing learning strategy in the room.)

The idea is for the challenge to relate to what they are studying around that time in class, though it might not be fully explainable with only the materials I've provided.

The first challenge I presented, this week, in our first unit on energy, was this:

Some engineers have suggested this hypothetical method of transportation between two cities, say New York and LA: Drill a straight tunnel underground and lay track. When a train is released at one end of the track, it would require almost no energy from an engine to reach the opposite end.

What would propel it? How would this work?

which is adapted from a scenario in The Flying Circus of Physics by Jearl Walker.

When I presented this, there was instant interest in the room. In most of my classes, the students were irritated to learn I wasn't going to tell them the answer and they had to wait until Friday! A few select kids kept coming up to me throughout class asking if their new hypothesis was right, some for the whole week.

Today was our discussion and debrief. I quickly adapted after first period (as it always goes, sigh...) and had them start in table groups by drawing a model of the train on whiteboards and using the intentional conversations tool to log the big ideas from their discussions.

After bringing the class together, I had a student scribe on the board with me and we started by collectively building a model. Next to the challenge model, we drew out a model of the skateboarder from the Energy Skatepark PhET Simulation which had been one of their learning activities in the week. We used this as a proxy for thinking about the train, and the analogies were powerful! By the end of the debrief we had not only constructed a model explaining how the train worked using conservation of energy and the second law of thermodynamics, but we'd reviewed essentially every key piece of their learning objectives from the week - without doing any kind of lecture or basic check-in type questions.

That said, this was a hard first challenge and it had a lot to unpack, so it ended up taking about 2/3 of the class instead of the roughly 1/3 I'd hoped for (and in one class, it actually took 45 of our 50 minutes). I was transparent with students and said I felt the extra time was worth it, and gave them the option to extend an assessment to Monday if they chose (since most of the class this early in the year is still at about the same place, and they were planning to take their first or second assessments today).

Additionally, an ongoing area of growth for me is negotiating the dance between over-interjecting myself and leading students versus facilitating them getting there themselves. I know I definitely led them too much at times today, in part because I felt pressed for time but also in part because I felt pressed to make sure they were getting it, not yet fully trusting myself and my abilities in facilitating a self-directed class, despite how much I fully believe in its value and that it is the right thing to be doing by my students in terms of their overall growth as thinkers and scientists.

Next week's challenge is much shorter and simpler to explain. Perhaps for that I will come up with some guiding questions in advance. Maybe I should even let a student use my list and facilitate, see how much I can get myself off stage.