Days 113-117: Final Exams

This week wrapped up trimester 2. Staff and students alike are very ready for spring break.

Physics

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.

Days 110-112: Energy Pie Charts & Pendulum Practical

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.

Days 105-109: Energy & Pendulums

Physics: Energy

Students did a lab to introduce energy where they pulled carts up ramps at different angles, always raising the cart to the same height above the table, then measured the average force they needed and the distance they had to pull the cart for each angle. Then, they sketch force vs. distance graphs and see they always have the same area. The data was rough enough this year that students could see that a steeper angle required a larger force and a smaller distance, but the areas varied a lot. We’ve had a few labs lately where the data came out pretty rocky. I think part of what’s going on is it’s been tough this year in general for students to see connections between what happens in the lab and the physics concepts we are learning. If the labs are something disconnected from the rest of your learning, why would you invest time and attention into collecting high-quality data? We’re also at the end of a trimester when more students than usual are scrambling to raise their grades after an unusually challenging term and the February doldrums have been hitting everyone harder than usual, so students have less attention and mental energy to go around than usual. Aside from the final, we won’t have any more labs until tri 3, which is a good time for a fresh start. In the meantime, the other physics teacher and I need to do some thinking about how we will continue to draw connections between labs and physics concepts and make sure students have what they need to get good-quality data.

AP Physics 1: Pendulums

This week, we started working on simple harmonic motion. For the first activity, students used a video from Pivot Interactives that shows a pendulum, a cart attached to springs, and a spinning disk all in synchronized simple harmonic motion. Students made position vs. time graphs for each object, which always works well for some discussion not only of how the motion of all three is similar, but to establish some important ideas like the non-constant force and the repeating patterns in the motion of each object. After that, we dove into a deeper focus on pendulums by doing a lab to find the factors that affect the period of a pendulum. This model is going to be split over spring break, which got me thinking about how I currently have the unit structured. Right now, I have one standard for pendulums and one standard for springs. But, especially since I start by emphasizing how similar those two kinds of motion are, I wonder if it would make sense to instead have a standard about using multiple representations like motion graphs and energy bar charts to describe simple harmonic motion that includes both springs and pendulums, then a separate standard on the mathematical relationships and factors that affect the period which also applies to both pendulums and springs. That seems like it would better represent the different kinds of thinking I ask students to do over the course of the unit.

Days 100-104: Momentum Conservation & Projectile Practical

Physics: Momentum Conservation

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.

Days 95-99: Cart Explosion Lab & Projectile Graphs

Physics: Cart Explosion Lab

This week, we wrapped up the cart explosion lab and started working on momentum bar charts. My students had really good results on the cart explosion lab, but connecting it to momentum in the discussion is always rough. Students launch a spring-loaded cart and a standard cart off each other, figuring out where on a track to start them so they reach the ends at the same time, then record the ratio of the cart’s masses and the ratio of the distances they travelled before changing the mass and trying again. While I love that this low-tech approach incentivizes students to look for a pattern while they are collecting data, students struggle to connect the distances travelled to the velocities, I think mostly because there are so many different numbers flying around. During the discussion, my students had great results, but needed a lot of support to connect them to momentum. I want to rethink our momentum unit anyway, and I think part of that will include clarifying what I want students to get out of this lab and whether there are better ways to achieve that purpose.

AP Physics 1: Projectile Graphs

We started the week with a Pivot Interactives activity that shows three views of a projectile (full disclosure: I am an activity writer for Pivot Interactives). I’ve done video analysis, but I really like the way seeing the motion from different angles solidifies what I mean by the horizontal and vertical motion. It’s been a while since we did much with velocity vs. time graphs and students made solid connections to the forces acting on the projectile. We also worked through an activity I got from Michael Lerner where students describe the motion of an orange falling from a tower using every model we’ve learned so far, which really helped reinforce for students are aren’t really doing something new, just applying what we know to a new context.

Days 90-94: Impulse Problems & Energy Practical

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.

Days 85-89: Impulse & Energy Problems

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.

Days 80-84: Impulse & Bouncy Balls

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.

Days 75-79: Values and Beliefs & Elastic Potential Energy

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.

Days 72-74: Unbalanced Forces & Kinetic Energy

We had a short 3-day week to lead us into break.

Physics: Unbalanced Forces

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.

A cart on a track with two photogates. The cart is tied with a piece of string to a force sensor and is held in place just before the first photogate.

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.

A silicone puck is levitating over a curved magnetic track. The puck is held in place near the top of the track by a small block of wood.