We had a four-day student week for a professional development day on Friday.
AP Physics 1: Waves
This week week we worked on developing and using the wave equation, as well as a few other concepts on mechanical waves. We started with a standing wave lab in Pivot Interactives. On a few labs this year, students haven’t taken the time to get good quality data, which has made it tough to make sense of the slopes during the board meeting. As students are getting better at constructing new ideas from lab results, they are starting to really see the value in having good results to discuss and this lab was a place I saw it really pay off. Students worked through linearizing their graphs and figuring out units of their slope with very little intervention from me partly because they knew those steps would help their sense-making and partly because they are getting more skilled and need less support. Every group had beautiful data for the board meeting and, as we worked on problems later in the week, I heard a lot of students referring back to their graphs or their qualitative observations to think through a problem. All around, this was a really fun week to watch and listen to my students.
Physics: Momentum Transfer Practical
Students worked on applying conservation of momentum to problems, including a lab practical. For the practical, students had to determine an unknown mass using photogates and a dynamics track. The groups that were able to sketch momentum bar charts that matched the collision they decided to do were typically able to find their mass pretty quickly, but a lot of students struggled to connect their bar charts to what was happening on their lab table. As we move into energy, I need to think about how I’m going to make sure students are connecting representations like bar charts to things they can observe or interact with in the lab and beyond. I did enjoy seeing the different approaches groups took to the practical. One based their approach on cart explosion lab and added mass to their empty cart until both carts had the same velocity after the explosion.
Students used a modified half-atwoods to find a relationship between force and acceleration. The quality of the results varied a lot. I’ve been talking to the AP Chemistry teacher, and we think part of what’s going on is students aren’t often asked to use their data in meaningful ways before they get to physics, so it doesn’t make sense to take the time and attention to collect data carefully. I need to put some thought into how to help students place value on good data collection and build the skills required to collect good data.
After developing Newton’s 2nd Law, we spent some time combining the new equation with vector addition diagrams. Students are starting to buy in to the diagrams as useful thinking tools, which is always a lot of fun to see.
Physics: Free-Body Diagrams
Students have been working on Newton’s 1st Law and drawing free-body diagrams. We have some problems that often lead to great discussion with mistakes whiteboarding, but I’ve been struggling to get students in one of my hours to speak up during whole-class discussions. To help with that, I tried doing a short gallery walk prior to any of the whiteboard presentations this week. Once the whiteboards were ready, I had students visit each board with their group and make notes on their worksheet about potential mistakes they saw or questions they had. During the whole-class discussion, there was a lot less silence and we heard from some students who don’t often speak up, which was exactly what I was hoping for. I think it also helped that I shared those goals with students before we started. When a student joked those goals aren’t going to happen, I assured her I’m very stubborn and am convinced the class can get there.
This week was a little goofy. Students were off Friday for a staff development day and it was homecoming week, so classes were shortened on Monday and Thursday for festivities.
AP Physics 1: Free-Body Diagrams
This week was all about Newton’s 1st law. We started with the bowling ball lab to come up with a formulation of N1L, then worked on representing forces with free-body diagrams and system schema. Both sections had mistakes whiteboarding sessions that were overall really good. There was a debate about whether a projectile should experience air resistance that had a lot of good thinking. We ended up grabbing a softball out of the storeroom and capturing an image of it rolling in Motion Shot to see if it had a constant velocity. There was a much more intense debate about air resistance than I’ve seen before and I think the group presenting felt like it became a “gotcha” moment. I need to think about how I could have intervened differently in that discussion to shift the tone it took on.
Physics: Constant Acceleration Model Building
Students used video analysis to produce graphs of the motion for an object on a ramp. I was ornery about making students attempt to follow a reference guide I made before I’d help with the technology, which made it a lot easier for me to spend time with students who needed help troubleshooting. The results were better than when I’ve used photogates, but still fairly messy. I think part of the problem is, regardless of the approach, students rush on key pieces and get sloppy data as a result. I need to think about how to slow my students down at key steps. It was also tough to get students to speak up during the board meeting, even with doing a gallery walk and jotting down some observations with their group beforehand. I’ve got more students than usual who underestimate how much they know and are wary of jumping in as a result. I have some work to do on increasing the social safety in my classroom and helping students recognize their contributions.
Students also did Kelly O’Shea’s CAPM card sort. Interestingly, even though this fell on the day of our homecoming pep fest, students were overall very engaged in the activity. I saw a lot of the same students I struggled to get to speak up during the board meeting asking great questions and sharing ideas during the card sort. I think the small group setting was a factor. I need to give some thought to what else made students comfortable speaking up so much in their small groups and how I can bring that to whole class discussions.
This week’s big theme was using precise, specific language in physics.
Physics: Buggy Lab & Problems
Students did the buggy lab, then worked on some problems with constant velocity representations. We went over the problems using Kelly O’Shea’s mistakes whiteboarding. Both during the buggy board meeting and during the mistakes whiteboarding, students used a lot of phrasing like “the slope is increasing” to indicate a positive slope or even just saying “the buggy was decreasing”, rather than specifying what about the buggy is decreasing, which made for some good opportunities to pick apart that wording and try to find ways to make it clearer what they meant. A few students seemed like they were frustrated by these conversations, especially during mistakes whiteboarding when a group didn’t consider that one of their mistakes, which tells me I need to keep working on emphasizing growth.
AP Physics 1: Problems & Acceleration Model-Building
AP also had their first round of mistakes whiteboarding this week. While we had some similar conversations about language, I noticed fewer students who seemed frustrated by those conversations. I don’t think I approached getting nitpicky about wording differently than I did in Physics, so I’m not sure if the AP students were doing more hiding their frustration or if they are bringing something to the class that leaves them less bothered by me getting picky about language.
After the problems, we started a model-building lab for constant acceleration where we used photogates to produce a position vs. time graph for a cart on a ramp. This lab is fairly teacher-directed since its the first time students are using any LabQuest probes, and it takes a while to get through. I’ve thought about switching to motion detectors or video analysis, but with the limited computer access I usually have, I like that photogates produce data that students can linearize. My building added a lot more laptop carts this year, so I might try one of the other options when Physics gets to acceleration.
School started on Tuesday! This week was all about setting the culture for my classes.
AP Physics 1: Buggy Lab
We dove right in and started the buggy lab on day 1 to start building the constant velocity model. Once again, I used Frank Noschese’s take that “Any lab worth doing is worth doing twice.” On day 1, I just told students to make a graph on a whiteboard that represented their buggy’s motion. There was a lot of variation and other messiness in the whitebaords, which lead the post-lab discussion naturally into how we could prepare whiteboards in a way that set us up for a better discussion. On Day 2 and 3, we repeated the lab, but with some agreements in place to make the whiteboards easier to discuss.
Last year, this approach felt like I was doing some “expose and shame”, but I really liked that it gave an authentic reason to agree on certain details as a class before data collection. This year, I tried to address that by starting the discussion on day 1 by explicitly addressing the fact that every group met the standard set in the directions I gave and talking about the benefits of the different representations we saw. When we switched to talking about changes to the lab, I emphasized that we would be approaching the second round with a focus on being able to communicate and compare results. I also kept the focus on what students needed from me, rather than what students needed to do differently, if we were going to focus on communicating and comparing. This framing of the discussion felt much better to me.
Partly to avoid sharing equipment and partly to limit how much students have to retain from the first lab, we started by asking students to predict the mass of a large dowel by finding a relationship between the mass and volume of smaller dowels. Similar to AP, we did the lab twice. On the first day, I just asked students to predict the mass of the large dowel, and many ended up using measurements from a single smaller dowel. That lead to some nice discussion on how measuring more small dowels would reduce uncertainty. It also lead nicely into graphs as an easy way to look at the ratio between mass and volume of several dowels simultaneously. For the second round of the lab, students used the lab template I put together for the course.
Students worked on polishing their final projects. One student needed to measure some angles in a video clip on Netflix, and had the brilliantly simple idea to just hold a protractor against her screen.
Physics: Review Whiteboarding
Students whiteboarded problems off the final review. A few students asked to chose their own groups since this would be our final round of whiteboarding, but I’m glad I stuck with shuffling them since there was some great conversation during the first few minutes when students were comparing answers on their problems.
Chemistry Essentials: Half Life Problems
We had a board meeting with the results of yesterday’s lab, then students worked on some half life problems. I don’t think I do a great job of linking the lab to the calculations, and I could see it in the ways students were struggling with the calculations.
Final project proposals are due tomorrow, so students worked on finalizing their topic. I got to have a lot of fun conversations today to help students narrow down their topic. One student had picked out a clip from The Cat in the Hat but wasn’t sure what she wanted to do with it, so we spent some time talking about the physics involved.
Physics: Curved Mirror Board Meeting
We whiteboarded the results of yesterday’s lab to get to the mirror equation.
Chemistry Essentials: Activity Series Practical
Students got a pre-1982 penny and a post-1982 penny, each with a wedge cut to expose the insides, and used an activity series to predict which would react with hydrochloric acid.