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.
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.
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.
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.
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.
This week wrapped up trimester 2. Staff and students alike are very ready for spring break.
We stuck with our usual structure of using half the final exam period for a lab practical and half the period for an individual written final. One of the interesting things is that while students have been struggling to collect high-quality data during labs, most groups had pretty accurate results on the lab portion of the final. I think a lot of students have been struggling to connect different representations in general, including how their lab data connects to the concepts and mathematical models we are using. If students see the labs as disconnected, why should they invest the effort to get good quality data? I think that’s become self-reinforcing because when few groups have good quality data, it is harder to see the connection between the labs and the models we are developing. The new trimester will be a good time to interrupt this cycle. I think we will try collecting data as a class for a lab so that I can model things like graphing as I go and re-doing data points that don’t match the apparent pattern. On the final, I think grades provided an extrinsic motivation for high-quality data. I don’t want to default to making data quality a part of a students’ grade in my current grading system, but I could provide other extrinsic motivation like stickers for being below a given percent difference from the accepted value.
AP Physics 1
Students took a practice AP exam for their final. I’m really pleased by how well students scored, especially I gave students the full multiple choice even though there are some topics we haven’t covered yet. On the free response, I noticed some students struggled with parsing what the question was actually asking for, which is not unusual. Especially once we wrap up content and focus on review, I think I need to make sure we spend time on reading strategies for making sense of AP problems.
With President’s Day on Monday and a PD day on Friday, we had a 3-day week.
Physics:Energy Pie Charts
This week we did mistakes whiteboarding with energy pie charts. There was some great discussion, both as students prepared and as they presented the whiteboards, that came from students working through what differences represented someone making a mistake vs. what differences represented different, but equally valid choices.
We also briefly revisited momentum transfer this week. On the last quiz, I saw a lot of evidence that students were struggling to connect the equations and math for conservation of momentum to their momentum bar charts, which fits with a larger pattern I’ve seen this year of students struggling to connect different representations. As we get into conservation of energy at the start of next tri, I need to give a lot of thought into how I’m going to support students in making connections between mathematical and graphical representations. I do a lot of card sorts to try and help with these connections, but I think I might need to plan some discussion that specifically focuses on how the mathematical representations relate to the diagrams.
AP Physics: Pendulum Practical
This week, we wrapped up pendulums. My students could use more practice and feedback on designing experiments and writing procedures, so I decided a pendulum practical would be a good opportunity to practice this. I tasked students with finding the length of a string without using a meterstick or ruler. Before they could get their string, they had to write out their procedure on a whiteboard and get it approved by me. I think this would have been tough to manage in a large class, but I currently only have 11 students in AP, so was able to pretty easily take time to give groups meaningful feedback and check their revisions before cutting them a piece of string to use.
This week we did a lot of work on conservation of momentum. We started with using photogates to measure the velocity of carts before and after a collision to reinforce the idea that momentum is transferred, then we did a momentum representations card sort from Kelly O’Shea before students tried some problems on their own. One thing I noticed is a lot of students are still struggling with what momentum is. I think a lot of students were having trouble taking in new ideas during distance learning, and are now struggling to build on those ideas. Students had a lot of great conversations during the card sort, and it was a lot of fun to see how they applied that thinking to the problems later in the week.
AP Physics 1: Projectile Practical
This week we wrapped up projectile motion. Students did a projectile practical where they predicted where a marble would hit the floor. I like to take advantage of the different masses of marbles I have and ask students to predict how the landing spot would change if they switched to a lighter marble, and students consistently nailed it. One fun thing has been seeing students use multiple different models to think about projectiles and the confidence I’m starting to see from more students.
This week we were back in-person after two weeks online.
Physics: Impulse Problems
A big theme I saw across my classes is that students had a pretty decent grasp of impulse, but didn’t think they had learned much the last two weeks. I kept thinking about my PhD research so far where, in some data I collected pre-pandemic, I found that even when students were mastering the material, they struggled to build confidence and self-efficacy from activities that were purely computer-based. In addition, right before we went online, my students also made clear that they really value discussion and collaboration as a way to learn physics, but I struggled to get students talking to each other online. With those things in mind, this week was all about giving students space and time for discussion and collaboration to build their confidence. We spent a lot of time whiteboarding various problems, including some that were assigned while we were online, so that students could talk to each other. I also gave much more feedback than usual while students were working on whiteboards to point out what they had correct or what they were doing well, which seemed to really help students see just how much they had learned the past two weeks.
AP Physics: Energy Practical
My students have been feeling pretty good about doing problems with conservation of energy, I think in part because we were able to start them in-person, then do a lot of practice while we were online. I wanted to give students something hands-on before we wrap up energy, so I got out the popper hopper toys and tasked students with finding the spring constant. To help my students with writing procedures, I had each group write a procedure on a whiteboard, then give it to another group to follow. They were allowed to go ask the group who’d written the procedure questions to clarify steps or discuss changes as both as a way to give feedback to the group who wrote the procedure and to ensure that every group was able to complete the task, even if there were issues with the procedure they were given. I think that helped give students a concrete target for what needs to be in a procedure.
We wrapped up unbalanced forces this week with a lab practical. I put a cart on a ramp, held in place by a string attached to a force sensor. Students had to first predict the tension in the string and next predict the time it would take the cart to travel between two photogates on the track once I cut the string. It was trickier than I expected for students to recognize that the tension in the string would be the same as the net force on the cart once the string was cut. Since that was an important idea in the paradigm lab we did this year, I left students to figure out that point on their own, but I think it would have been worthwhile to give students some questions or other structure to think through that aspect of the practical. We haven’t revisited velocity vs. time graphs lately, so I was very excited to see how well they did annotating their graphs and setting up equations to find the time.
AP Physics 1: Kinetic Energy
Students used Pivot Interactives for a lab to find the mathematical model for kinetic energy. Their data came out beautiful, but the introductory section of the activity didn’t do as much as I’d hoped to prepare students to collect data. This fits with a larger pattern I’ve noticed this year where students in both my courses don’t seem to make a clear connection between the pre-lab discussion (which the introductory section was similar to) and the actual lab. I think I haven’t helped students make a clear connection between the experimental design thinking we do in those discussions and what they will actually need to do in the lab. I’m giving some thought to how I can do a better job of showing how those discussions lead naturally to what students will be doing in the lab.