We spent most of the week on the pendulum lab exploring the variables that affect the period of a pendulum. This will be our last model-building lab for the year, so it was good to see students figuring out plans for data collection and getting high-quality data with minimal intervention from me. Connecting the data to a mathematical model was still tricky for students, but they worked through the challenging parts to figure out what was going on. They really hated the unit on the slope of their period vs. square root of length graph (I don’t blame them!), but I was able to use that as motivation to try and get a nicer unit by rearranging things so that we had the length divided by a number in m/s^{2}. From there, students were quick to suggest that the slope has something to do with gravity. From there, I showed that the value happened to work out if we put a 2π out front. This approach could use some refining, and I’d especially like to put more of the thinking on students, but students did seem clearer on the significance of the slopes of their lines than in the past.

AP Physics 1: Review

With the AP exam on Thursday, the first three days of this week we focused on review. My students this year really liked Plickers for multiple choice and had some great discussions, when whole class discussions have generally be tough this year. I wonder if I should have pulled out Plickers earlier in the year as a way to get them talking and to build up to some other types of class discussions.

I had a brainstorm for a review activity, that unfortunately came the day of the AP exam, so too late to try. I do a lot of having students start by just looking at the diagram and scenario description, then deciding what models seem useful and sketching some diagrams. It crossed my mind this could lend itself to a card sort, so I put one together with the released free response to date. I haven’t tried it with students, but I think I would start by having students match each prompt to at least one of our models, then give each group a problem to sketch some diagrams and brainstorm what they could figure out.

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.

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 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.

This was our second week of virtual instruction. We are slated to be back in person on Monday.

Physics: Impulse Problems

Students worked on problems using the impulse-momentum theorem. I noticed that a lot of students were struggling to retain new information much more than usual, which made the problems relatively challenging. I’m sure some of it is a lot of students are less focused right now than in the classroom (at least some of them for very good reasons, like helping take care of younger siblings that are also at home), but I it’s also a factor that I didn’t make much effort to encourage student-to-student discussion and I did more providing new information than usual, rather than simply stepping in to put language or standard formulas to things students had already said. I’m not beating myself up for it since those things are difficult online in the best of circumstances, and I was doing it with minimal time to prepare and no prior experience teaching high school online. But it is a good reminder that the time I spend on those things in the classroom is important. While we have done versions of everything we normally do before the impulse quiz, I’ll be taking a few days next week to have some in-person discussions before we assess for the first time.

AP Physics: Conservation of Energy Problems

Right before my school switched to remote instruction, my students started working some problems using conservation of energy. We didn’t get a chance to whiteboard or discuss the problems, so we revisited them this week. My students had some good conversation using Jamboards and a discussion forum and seem to be doing pretty well with conservation of energy problems. I still want to do some in-person whiteboarding before we assess to get a better sense of where students are at since there are a few who’ve shared they are having some of the same trouble focusing I saw in Physics. I’ve got some problems from the AP Physics 1 workbook that I think will be good for this purpose.

Around mid-day last Friday, we found out enough staff were out (almost all with COVID) that we would be remote this week. Monday was an asynchronous day so that teachers could post an assignment, then spend the rest of the day planning for the rest of the week. The rest of the week was synchronous following our usual bell schedule. We were required to have some synchronous instruction at the start of each hour, but were encouraged to make the rest of the hour something that students could do away from Zoom. In both my courses, I stuck to activities that should be doable in class time, but made them due at midnight rather than the end of class. I got really positive feedback from students since that gave them the option to take a break from their screen and do their physics later, especially for my classes in the middle of the day. That also meant I had time to look over their work before school and make some adjustments to the instruction I’d planned for the day. I think being transparent about how student work was informing my instruction also helped with work completion, since it gave students a clear reason to at least attempt the work on the day it was assigned.

Near the end of the school day on Thursday, we found out that next week will be remote, as well. Next week, I want to keep the same general structure since that seemed to work well for both me and for my students, but I want to try and get a little more student-to-student discussion.

Physics: Impulse

Our plan this week had been to introduce momentum and impulse. We normally start with a cart catching activity, where students find as many ways as possible to make it harder to catch a cart. That translated fairly well to an asynchronous lesson for Monday where we asked students to brainstorm ways they could change how difficult it was to catch a ball during a game of catch. I put all of the responses onto a Jamboard and did some sorting, which lead very nicely into a definition of momentum as well as the idea that force can chance momentum.

The rest of the week we relied heavily on Pivot Interactives (disclaimer: I work for Pivot Interactives writing activities). We started by introducing Newton’s 3rd Law, which we’d decided to save for momentum this year since that’s when students seem to do the most interesting and useful thinking with it, then did an activity where students evaluate two competing claims about what is transferred in a collision between two gliders on an air track. We haven’t done many of those kinds of questions this year, so students needed some support in figuring out what kind of evidence they needed, but it was mostly a matter of keeping them focused on the claim and not overcomplicating what to collect. The bit that got a little rocky is I tried to go from there to the impulse equation, which just didn’t flow naturally. I’ve thought about changing my momentum storyline to start with conservation, then narrow our focus to the individual objects that make up the system to look at impulse. In retrospect, a part of me wishes we’d made the leap when we switched to remote instruction since I think that storyline would have flowed better with the resources available to us, but sticking with the storyline we’d already planned took less thinking and will likely make for a smoother transition when we get back to in-person instruction.

AP Physics 1: Bouncy Ball Energy

As part of my energy unit, I’d planned to do an activity (shameless plug for my article on this activity in The Science Teacher) where students use video analysis to decide whether a bouncy ball dissipates energy primarily due to air resistance or due to the impact when it bounces. The hard part of this activity is prior to the video analysis, I have students do some whiteboarding where they sketch representations including LOL diagrams, free-body diagrams, and velocity vs. time graphs for the bouncy ball-Earth system first assuming only air resistance dissipates energy, then assuming only the impact dissipates energy. I ended up using a version of this activity I wrote for Pivot Interactives that replaces that whiteboarding with multiple choice questions. I have struggled this year with helping my students effectively use diagrams as thinking tools, so I think having them choose from a set of diagrams was a useful scaffold. I had the questions set to autograde, which made it easy for students to progress asynchronously, but I think some good discussion could have happened if I’d turned off autograding and instead had students use our synchronous time to discuss their answers and come to a consensus.

This week has felt a little weird. Coming back from break, we’d gotten some messages to be ready to shift to virtual learning and all week the number of students and staff out went up, so everyone felt like we were in limbo. Near the end of my teaching day today, we got word that next week will be remote.

Physics: Values & Beliefs About Physics Learning

We started this week with a version of the values and beliefs lesson from Kelly O’Shea. There wasn’t as much discussion within groups as I was hoping (and it probably didn’t help that I was giving groups more space than usual to try and reduce my COVID exposure), but students had some great insights and really interesting things to say on the individual reflections I had them complete. One thing I felt like was missing in how I implemented this was some conversations about the costs and benefits of different views of physics and physics learning. One of the last things I had students do in their groups was pick some values or beliefs they think we should aspire to, and a lot of groups said we should aspire to do a better job of valuing memorizing facts and equations. I wonder if giving more space to why certain values and beliefs are or are not given a space in a particular classroom would have helped with some conversation about why they see memorizing as important and whether that is compatible with our classroom.

After two days of that, we spent the rest of the week on some problems about pushing cardboard boxes based on problems in Matt Greenwolfe’s More Models in Modeling materials. My goal was to refresh students on velocity vs. time graphs and free-body diagrams before we dive into momentum. There was a lot of great discussion, with lots of animated arguments. I was also really pleased at how often I could have students simply add a diagram, such as a system schema, to identify and fix their mistakes. I still need to work on how to facilitate a good whole class discussion with these problems, but I think part of the issue is I approach these problems with what I call consensus-building discussions, where I have every group whiteboard the same problem, then we try to resolve differences, but I don’t do this type of discussion very often so students don’t have much practice with it.

AP Physics 1: Energy

This week, we focused on going from LOL diagrams to doing calculations with conservation of energy. We started by doing a lab to find the equation for spring potential energy, which gives us all of the major energy types, then did a card sort that included equations based on just the types of energy and equations based on measurable quantities like velocity, mass, and height. The card sort made for a very nice bridge between the two types of mathematical representations.

I think last week is the first time I missed a post on this blog. The end of my grad school semester plus the usual challenges of the Thanksgiving to winter break stretch got the best of me.

Physics: Unbalanced Forces

Last week, we did a paradigm lab for unbalanced forces. I was really dreading the classic half-Atwood machine, so tried a lab Kelly O’Shea suggested. We set up a ramp, then used a string to connect a cart to a force sensor. Next, I cut the string and students observed that the cart accelerated down the ramp. Students were able to reason out that the tension in the string before it was cut must match how unbalanced the forces on the cart are after the string is cut. Students also were quick to recognize that we could change the tension in the string by changing the angle of the ramp. Students then went and collected data to find a relationship between the size of the unbalanced force and the acceleration of the cart. Compared to the half-Atwood, students had a much clearer conceptual understanding of the lab and the data was much cleaner, so I will be sticking with this approach.

This week, we introduced problems by starting with a card sort where students matched a situation to the motion map, free-body diagram, and vector addition diagram. The acceleration arrows on the motion maps seemed to help students with thinking about the direction of the net force, though a lot of students needed some prompting to use the motion maps. I think that is because they haven’t been a very meaningful sensemaking tool in my class before now. If I want students to be ready to use them with unbalanced forces, I need to give some thought to how I’m going to push students to make meaning from motion maps when they are first introduced.

AP Physics 1: Conservation of Momentum & LOL Diagrams

Last week, we worked on conservation of momentum. I introduced momentum bar charts so we could do some problems from the College Board’s AP Physics 1 workbook. They seemed to really help students, so I wish I’d introduced them much earlier. Students ended up not making much connection between the problems we’d done earlier and the momentum bar charts, so I think I needed to introduce the bar charts right off the bat. The quiz didn’t go as well as I would have liked, but next week’s quiz will include a retake. I’m thinking about what I want to build into class next week as a way to address the gaps I saw on the quiz.

This week, we’ve been focused on energy bar charts and LOL diagrams. We did a lab I’ve done in the past where students raise a cart to the same height above the table using ramps of different angles to see the force vs. distance graph always has the same area. After that, I defined the major forms of energy we’ll be dealing with and students practiced drawing energy bar charts, including for situations where they switch between systems. These are coming really easily to my students and we had some great discussions using mistakes whiteboarding on some bar chart problems. The big challenge will be helping my students revisit these ideas after break.

We are almost at the end of the trimester! Both classes wrapped up a topic, then started reviewing for the final.

Physics: Constant Acceleration & Balanced Forces

Students worked on a packet of problems. One nice thing is many students were working more independently than usual, so it was easier for me to give more intensive support to students who’ve been struggling. It was really great to see how many students had moments where something we’ve been working on finally clicked.

AP Physics 1: Model Summaries

We started the final review with model summaries, where each group takes a model from so far this year and prepares a whiteboard with the major representations including graphs, diagrams, and equations. My students didn’t have as strong a positive response this year as in the past, and I think that is probably related to some conversations I had this week where students weren’t aware that this class is organized by models. This tells me I need to get more intentional about using that language if I want students to think in terms of what models we have.

This week was mostly about working problems using the constant acceleration model, which I have students do almost entirely from velocity vs. time graphs. We started with some problems I got from Kelly O’Shea where students are given some velocity vs. time graphs they annotate and write area equations for. Next, we shifted to word problems. I was blown away by how easy these problems were for students. Doing calculations with the constant velocity model had been very challenging for a lot of students, but something really clicked this week. Students were even including units on all of their work with almost no prompting and showing their work really clearly. I’m not sure what it was, but it was nice to have a week where students were nailing what I gave them!

AP Physics: Force Equations

We did labs to find the equations for the force of gravity and for spring force. Most years, my students are most comfortable with mathematical representations and it’s a challenge to get them comfortable with other representations, but this year my students are defaulting to other representations in some really cool ways. At this point in the year, when I have groups make a graph on a whiteboard, they usually default to including an equation for the line of best fit whether or not I ask for it. Instead, my students this year have been writing “for every” statements about their slope unprompted. For example, on the force of gravity lab, every group wrote some variation of “The force goes up 10 N for every 1 kg” on their own. That tells me that my students find the “for every” statements useful and intuitive, which is a great place to be developing physics knowledge from.