Days 68-72: Energy & Forces

This was another week that was a little messy. I had a sub Wednesday through Friday so I could present some of my doctoral research at the ASTE conference. On top of that, we had an ice storm early Wednesday morning that resulted in a late start, so two of my classes didn’t meet

AP Physics 1: Energy

This week was all about applying our model of energy transfer. We had some great discussions before I left where students were navigating how different systems affect the problem. We also did some TIPERs problems where some common preconceptions came out. The last few years, I’ve been working on being more intentional about making sure we discuss what’s correct about those preconceptions and whether there are other questions those ideas are the correct answer to. My students this year have been really receptive to those conversations, which makes for fun discussions and seems to help kids feel comfortable sharing ideas. Once I left, students worked on an energy lab practical in Pivot Interactives and some energy problems from the College Board’s AP Physics 1 workbook. My students were a little nervous about doing those problems without a teacher who knows the content in the room, but I’m betting they will make some good progress with peer conversations.

Physics: Unbalanced Forces

Students started working problems using unbalanced forces. My students and I are getting more comfortable with each other, which is leading to the discussions getting better. That’s helped me make the connection that the reason some of my students have been struggling with the direction of some forces is they don’t have a great conceptual understanding of the interactions involved in some forces, especially the normal force. I made sure we spent some time reinforcing those ideas by doing some things like using the matter model for normal force and a pair of hairbrushes for friction. My go-to move is to place those on a board at different angles to help students get a visual and tactile hook to make sense of what direction the normal and friction forces should go, which seemed to help a lot of students. We also spent some time looking at how the normal force an elevator passenger experiences connects to the acceleration of the elevator. Once I left, they did an unbalanced forces lab practical in Pivot Interactives.

Days 57-60: Impulse & Force Practicals

We had a snow day on Thursday, so got a surprise short week. Plus some beautiful fresh snow to enjoy this weekend!

AP Physics 1: Impulse

This week, we wrapped up impulse. I tried a new sequence this year where I started with conservation of momentum, then shifted into impulse and using momentum for single objects. I feel like my approach could still use some refinement, but overall I felt like the storyline made a lot of sense. My students found it a little tricky this week when we did some problems where they had to switch between different systems when thinking about the same scenario, which tells me that’s something I need to make sure we keep working on. We are starting energy next, which is a good opportunity to keep working on the idea of systems.

Physics: Force Practicals

This week we did a lot of work doing problems with balanced forces. Students were in a lot of different places on their math skills, but were able to get the problems down. We finished the week with two different lab practicals. For one, students had to find the mass of a cart on an angled ramp. For the other, students had to find the mass of a bag hanging from two spring scales. I set up several stations for this lab practical on my whiteboard using hooked magnets, and I was excited to see some students sketch diagrams on the whiteboard right by their station. On both practicals, I was really pleased by how quick students were to check their answers on the scale I had out. Last year, it was really tough to get students to see the connection between the physical world and the math we were doing, and one way that showed up is a lot of students were not invested in checking their answers on lab practicals. I think sketching diagrams on the whiteboard next to the practical also helped cement the links between the representations we’ve been using and the physical scenario.

Days 32-36: Using Newton’s 2nd Law

This week, our big focus was on using Newton’s 2nd Law. Students were very successful at using vector-addition diagrams with unbalanced forces and did a nice job playing around with different systems on problems involving Atwood’s machines. We wrapped up the week with an extremely open-ended lab practical. I tasked students with finding the mass of a dynamics cart with a force sensor attached and left it at that. I did ask students to get my okay before they started data collection so I could make sure every group was on a good track. I was really pleased that groups ended up using several different approaches. Some did something similar to our model-building lab with a half-Atwood’s machine, some set their track at an angle to apply a force to their cart, and some manually pulled the cart. On Monday, I want to take a few minutes to make sure we talk about the different approaches, including the different ways uncertainty showed up in each.

Days 27-31: Balanced Force Practical & Newton’s 2nd Law Model-Building

This week we wrapped up balanced forces with a practical. I used some magnetic hooks to attach spring scales to the whiteboard and let students measure the forces and any angles they wanted. Even though I only had two setups and five groups, different groups ended up taking different approaches, which was great for students to see in some discussion after the practical. We also had some good discussion about uncertainty when we measured the actual mass and students were initially disappointed with how far their calculations were off before, which lead to the realization they’d actually been pretty on target!

After the practical, we started Newton’s 2nd Law with a paradigm lab using the standard modified Atwood’s machine. There was some messiness in the value of the slope that students got, which is pretty typical from when I’ve done this lab. One of these days I’ll figure out how to coach students to really high-quality results! Students did really well at translating the equations for their line of best fit into something that had units and variables that matched the experiment and did a nice job in the board meeting making sense of their slope and intercept.

Days 5-9: Deploying CVPM

This week was all about using the constant velocity of a particle model. We started with some problems translating between different representations that we went over using mistakes whiteboarding. Last year, I had some classes where it helped to do a gallery walk before the whole class discussion, so I decided to try that from the start this year. This class did a great job with the gallery walk and every student was able to say something about every whiteboard. They also did a great job during the whole class discussion. There was one whiteboard that sparked some great student-to-student talk where I could hear students getting a better understanding of motion maps as they talked.

We wrapped up the week by predicting where two buggies would collide. I told students there was a range of possible approaches, and one group took that as a challenge to find as many different approaches as they could. A homecoming pepfest on Friday meant we ran short on time to have students share how they approached the practical, but I want to make sure and revisit that next week.

I also set aside some time this week to work on good collaboration. That is something I was not very consistent about last year, and I think it contributed to how much some students struggled in groups. We spent some time discussing the different kinds of contributions that were useful this week to ensure students are seeing a variety of ways they can be good at physics. Next well, I’m planning to introduce group roles.

Days 15-19: Applying CAPM

This week was all about applying the constant acceleration of a particle model. Students worked some problems, including a few from the AP Physics 1 workbook. I had more students than usual try to use the formula sheet, but they pretty quickly shifted to relying on velocity vs. time graphs to solve problems, which I am all for. When we did some mistakes whiteboarding, I tried to keep the focus on setting up the problem by asking students to make a mistake in the velocity vs. time graph, annotation, or setting up an equation. I posted my solutions for the problems on Schoology after class so students could check their algebra later.

The highlight of the week was the catch the loot practical, where students figured out where to start a marble on a ramp so that it would land in a buggy driving by. This year’s students were much more invested than last year’s in getting a successful result, which makes me think they are more comfortable with hands-on work than my students at this point last year.

Days 167-170: Pendulum Practicals & Final Project

This was the last week of school for seniors! Since they are around 90% of my students, this was the last week of instruction in my classes. Next week, the juniors in my classes will have time to finish anything they still need to for my class or prepare for finals in their other classes.

Physics: Pendulum Practicals

This week we did two lab practicals using pendulums. First, we had students determine the length of a pendulum using only a stopwatch, which went really smoothly. Next, we had students figure out where to start a buggy so that the pendulum bob would collide with a passenger in the buggy. The big thing I noticed was students treating the period of a pendulum as three different equations, depending on which variable they were solving for. This fit with a general pattern this year of students struggling with using math in physics. While I think the unique challenges of last year are a factor, I think it would also be worth looking at our curriculum to see how we could do a better job of not just using math, but helping students develop a conceptual understanding of the math we are using. I won’t be able to work on that directly next year since I will be out of the classroom working as a high school science content specialist, but I’d like to think about how I can support teachers interested in that work. There will also be a high school math content specialist, and I think it will be worth having some conversations with him to think about how our departments could collaborate.

AP Physics 1: Final Projects

Students met with me about their final project drafts, then presented them to the class. I feel like while these students are phenomenal in small groups, I’ve struggled to build a whole-class community this year. During the presentations, however, there was a lot of joking around from both presenters and the audience, and several presentations included references to Throckmorton, who appears in many of our problems. I think we had more of a whole-class community this year than I realized, it just looked different than in previous years. It was really nice to have that so apparent on our last day together.

Days 152-156: Projectiles & AP Review

Physics: Projectiles

This week was a little hairy since students were in and out for AP exams. We continued working on using velocity vs. time graphs to quantitatively describe the motion of projectiles. We wrapped up the week with a practical to predict how far from the edge of the table a marble will land. I spent more time than usual working on breaking up the three phases of motion (constant acceleration while the marble is on the ramp, constant velocity while it rolls across the table, and projectile motion once it leaves the table), but it was still pretty challenging for students to connect when to use the measurements they made in their calculations. Based on the conversations I had with students, I think this fits in with a larger pattern I’ve seen this year with students struggling to connect labs to mathematical and graphical representations. As we move into the last few weeks of the school year, I want to make sure I keep thinking about how to support students in seeing the mathematical and graphical representations as meaningful descriptions of something physical.

AP Physics 1: AP Review

We continued reviewing for the AP exam. I didn’t do anything particularly interesting. We started each day doing a few multiple choice questions on Plickers, then moved into working some released free response. For the free response, I let students pick problems to work on based on the topics they want to work on reviewing. With both the multiple choice and the free response, I made sure we spent some time discussing what the problems illustrate about the type of things that tend to show up on the exam, things that tend to show up on the scoring guide, and strategies for approaching the question. A lot of my students have resisted using the formula sheet this year, and it’s been good to see students getting more comfortable referring to it this week and even using formulas to figure out the significance of the slope and area of graphs they are rusty on.

Days 147-151: Free Fall Practicals & AP Review

Physics: Projectile Practicals

It’s been tough for students to make connections between labs, diagrams, and mathematical representations this year, so I was nervous about the shift this week from sketching diagrams for projectile motion to doing problems. I had a brainstorm on my way to work for scaffolding that transition that worked out really well. First, we did a lab practical where each group got a strip of clear acrylic and a random time. They were tasked with calculating how far apart they should place pieces of tape so they could get a photogate to read their time. That meant students only had to think about the vertical motion, which seemed to help with connecting measurements, diagrams, and mathematical representations.

The next day, I wanted them to think about motion in both directions, but keep the distinction between those two directions very concrete. We tried a lab practical I’ve seen where each group got a random distance for a constant speed buggy to travel, then had to calculate where to drop a marble from so it would land in the buggy. The two separate objects seemed to help students wrap their heads around what we mean by the vertical motion and what we mean by the horizontal motion and why the time must be the same for both.

At this point, we talked a little about how thinking about the motion of the buggy and the motion of the falling marble simultaneously was similar to thinking about the motion of a projectile. Students seemed to make that connection really nicely. One benefit I hadn’t thought about in advance is they also seemed more confident starting the problems, having already had multiple, tangible successes with this kind of thinking. This seems like it could be an argument for putting lab practicals or similar experiences early in a unit, rather than only toward the end where we tend to use them.

AP Physics 1: AP Review

We wrapped up angular momentum and started reviewing for the AP exam. We spent some time on model summaries, where students revisited the diagrams and equations central to each major model we’ve used this year. The next day, I handed out the 2021 free response and we took some time to just read the problems and talk about things the students noticed. Next, I gave students the scoring guide and we made some observations. Finally, I handed out the student samples that are publicly available to make more observations. This lead to some good discussion about what the readers are looking for as well as some good conversation about strategy, like how to make use of diagrams or the importance of taking the time to break apart the text.

Days 138-141: Popper Hoppers & Unbalanced Torque

We had Friday off this week. I think staff and students alike were very happy to have a long weekend.

Physics: Popper Hoppers

This week we wrapped up energy. After finishing the bouncy ball evidence-based reasoning from last week, we got out the popper hoppers to use energy to find the spring constant of the toy. We haven’t done as much having students decide what measurements to take as I’d like, so students struggled a little at first with what measurements to take. I showed them a strategy from one of my past AP students wo would write out the equation she was going to use to solve for the target variable, then put check marks next to each of the other variables once she had a step in her procedure that would get her a value for that variable. That was exactly what students needed to get a solid plan for the practical.

AP Physics 1: Unbalanced Torque

This week, we worked on unbalanced torque. We used another Pivot Interactives activity (Disclaimer: I work for Pivot Interactives as a content writer. This activity should be published soon!) since I haven’t had a chance to play with the hands-on equipment we purchased for rotation in fall 2019. I’m trying to be pretty conscious of making explicit connections to unbalanced linear forces, both to make sure students aren’t starting from scratch in their understanding and to embed review of earlier topics. Students are seeing those connections pretty clearly, which is great to see.

I also started a countdown to the AP Physics exam on my whiteboard, and noticed students are more focused when working problems. I think the countdown is adding some sense of urgency to what we are working on.