# Days 25-29: Mistakes Whiteboarding & Free-Body Diagrams

Physics: Mistakes Whiteboarding

This week we did a lot of practicing with constant acceleration diagrams. The highlight was doing mistakes whiteboarding. Based on a recent conversation with Kelly O’Shea, I was much more explicit that the role of the group presenting is merely to facilitate the discussion while the role of the rest of us is to help them get to the right answer. In two of my classes, this seemed to be really freeing for a lot of groups as they presented, and lots of students were quick to ask their peers to justify changes to the whiteboard when they were presenting. There was also some fantastic back and forth where the students who weren’t presenting disagreed about what to change on a whiteboard and had exactly the kind of discussion I’m after with mistakes whiteboarding. In my third section, the discussion was still pretty rough, so I need to give more thought to how I can support them in having deeper student-to-student discussions.

AP Physics 1: Free-Body Diagrams

This week we focused on drawing system schema and free-body diagrams. I was reminded how much I love framing forces in terms of interactions and the discussion that comes out of even the very basic free-body diagram problem set in the Modeling Instruction materials. I love that on a problem about a skater sliding across frictionless ice at a constant velocity, I get to hear students internalize Newton’s 1st Law as they wrestle with what interaction could be giving the skater a forward force. This year, my students also got into Newton’s 3rd Law during the discussion as one student pointed out the ice is pushed downward by the skater’s foot, so the class wrestled with how that impacts the normal force before agreeing that same interaction pushes the skater up and the ice down. We also did Kelly O’Shea’s force diagrams card sort, which I use as students’ first introduction to vector addition diagrams. I was really pleased by how easily they connected the vector addition diagrams to the free-body diagrams and by how they started contrasting balanced and unbalanced force scenarios with minimal input from me.

This year has felt unusually draining so far, but my students are doing some great work in my class and reminding me why this job is worth it.