Students used Vernier Video Analysis to get velocity vs. time and position vs. time graphs for a projectile. I saw some students including their throw or after the projectile landed in their video analysis, which makes sense since I’ve seen students struggling more than in the past with recognizing what is the most relevant part of an object’s motion. I think that probably could have been addressed with spending a little more time on some pre-lab discussion. It was a lot of fun to hear their small-group discussions making sense of the graphs once I had them draw a free-body diagram and they recognized why the graphs looked the way they did.
AP Physics 1: Angular Momentum We wrapped up unbalanced torque and rushed through angular momentum. Students started an activity in Pivot Interactives, but were moving through it more slowly than I’d hoped, so I ended up doing a lecture on angular momentum. It’s not my preferred approach, but the clock is ticking for AP exam day! Students seemed to get the concept during the lecture. I did a lot of emphasizing the parallels to linear momentum, which seemed to help. We’ll be doing some problems and whiteboarding next week to wrap up angular momentum, which will be a good opportunity for me to check how clear their understanding is.
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.
A lot of this week was working on calculations for constant acceleration. My students are struggling more with the algebra than in a typical year and it sounds like other teachers are seeing similar things. They are doing some great mathematical thinking, but just aren’t as comfortable as usual with common processes like making a quick graph based on an equation or doing algebraic manipulation. I tend to trust that once students see what math they need to do, I can expect them to get through the math without much support. This year, I need to make sure I’m putting attention to helping students develop their math skills alongside the physics. My course on STEM integration theories last fall got me thinking about how I can go beyond math as a tool in my classroom to instead support meaningful math sensemaking, and this year will be a good push to put what I’ve been thinking about into practice.
I also graded the first lab write-up this week, and my students did much better than I usually see on the first lab write-up. In general, this group of students are stronger than usual at explaining their thinking and the kind of writing I usually look for, which is fantastic in a course like AP Physics 1. I’m really excited to be able to help students build their already strong skills.
Physics: Technology Tools
This week, we wrapped up constant velocity by having students do activities with Vernier Video Analysis and Pivot Interactives. For the video analysis assignment, we had students record a short example of something they thought was constant velocity, then use the video analysis results to test the claim. Since the focus of this activity was on interpreting the position vs. time and velocity vs. time graphs, I think it would have worked well when we were preparing to transition from interpreting diagrams to doing calculations to help break up the stretch we had of paper and pencil problems.
A big goal of these activities was to introduce students to tools we’d been using in a context where students were already pretty solid on the content. When introducing technology, I do a minimal demo and instead provide students with a user guide or other detailed instructions on how to use the tool. I have a lot of students who are more comfortable with a walkthrough, so I spend most of the hour on my feet answering questions by reminding students to use the resources I provided them. These days are tiring, but they pay off with students quickly becoming very independent with these tools as they learn to navigate the user guide or help documents. However, I’ve developed some new back issues in the last year and a half and am very aware today that I can’t currently bounce around the room as much as I used to. We are using video analysis again on Monday, and I need to give some thought to how I will balance ensuring students have the support they need and feel like I’m available for questions with managing my own health.
Students whiteboarding yesterday’s problems. I focused on a consensus-building approach, where all groups whiteboarded the same problem, then we used the discussion to come to an agreement on what the answer should be, and why. Both my sections have a pretty good sense of class community, which made students pretty comfortable sharing work they weren’t sure about yet and building off each others’ ideas.
Physics: Video Analysis
We finally got out the computers to do some video analysis of a bouncy ball to figure out what interaction is dissipating the energy. I’ve never had much luck walking the whole class through the software, so I have a video analysis guide with lots of animated screenshots that I put on the class website. Students were able to get some nice graphs of the bouncy ball’s motion and connect them to our work from the past few days.
Chemistry Essentials: Board Meeting
Students whiteboarded their results from yesterday’s lab in Pivot Interactives. During the board meeting, students continued to share observations faster than I could write them down, which is a great problem to have in this course. It was also very clear to students that the temperature stays fairly constant during the freezing process. I’m hoping having had a board on these results will help students make sense of our lauric acid lab on Tuesday.
Students wrapped up their video analysis of a bouncy ball’s motion and started working on CER statements to answer what interaction dissipates the energy. I ended up doing more coaching than I usually do; I usually manage to squeeze this in before winter break, so I think it was just too long since students had been using free-body diagrams or velocity vs. time graphs. Nevertheless, students got to an answer today which was my goal.
Physics: Kinetic Energy
We had a pre-lab discussion and students collected data to work on a relationship between kinetic energy and speed. I found that a lot of students were confused about how to figure out the kinetic energy of the cart once they got into their lab groups. We went through the calculation during the whole class discussion, but I’m wondering if it would have been worthwhile to get students sketching some diagrams on whiteboards with their lab groups to figure out how they could find kinetic energy to get everyone wresting with those ideas, rather than just the students who spoke up.
Chemistry Essentials: Board Meeting
We held the board meeting for both of the gas laws labs students completed on Pivot Interactives this week. This trimester, my co-teacher and I have been trying to ramp up the graph interpretation we ask students to do, and today was a nice opportunity to see it pay off. Students were very successful at attaching conceptual meaning to the slopes of their graphs and, with a few questions to nudge them along, were also able to connect the intercept of the pressure vs. time graph to absolute zero.
Students worked on a video analysis of two air pucks attached by a rod from the article by Taylor Kaar, Linda Pollack, Michael Lerner, and Robert Engles in The Physics Teacher. In the past, I’ve used LoggerPro, but there have been delays on getting it installed on student computers, so I took advantage of the video upload feature in Pivot Interactives. Pivot has a ruler with an adjustable length to get measurements to scale, but it was tricky to find a nice alignment, so students ended up skipping scaling the ruler and coming up with a conversion factor, instead.
Students whiteboarded some problems on drawing free body diagrams. In my 1st hour, we did mistakes whiteboarding; I was a little disappointed that no groups put a forward force on the objects moving forward, but not a lot of students made that mistake while they were working on the problems in the first place. My 6th hour is a little behind, so they mostly worked on the problems today and will do some abbreviated whiteboarding tomorrow.
Chemistry Essentials: Energy Bar Charts
Students worked on some LOL diagrams for energy transformations during phase changes. They had some trouble with the system flow part of the diagram, mostly because they are getting tripped up by the idea that it needs to list specific objects.
Students whiteboarded their answers to yesterday’s problems. There were a couple of meaty ones on the worksheet, so I had all groups whiteboard the same problem and then we had several consensus-building conversations.
Students worked on a worksheet to connect particle diagrams to the vocabulary for classifying matter that we introduced yesterday. I also was able to have really good individual interactions with a couple of students I’ve been butting heads with a lot, which helped make the whole classroom feel more relaxed and positive. I’ve been getting overwhelmed in chemistry a lot this year and have not done a good job of making time to talk to students about things besides chem, and I can’t underestimate the value of those conversations.
Students started a video analysis activity by Taylor Kaar, Linda Pollack, Michael Lerner, and Robert Engles that recently appeared in The Physics Teacher. I gave students a video of two linked hover disks and had students first track one of the disks, then track the center of mass for the system. In their article, the authors say their students resist tracking the disks, wanting to jump straight to the center of mass. My students, however, were very happy to track the motion of the disks, which made for a really satisfying payoff when they saw how much simpler the motion of the center of mass is.
Linked hover disks; from video by Kaar, Pollack, Lerner, & Engles
x vs. t for disk (red) and CoM (green)
I’ve found a lot of groups are recording pretty incomplete data during labs. I think since groups don’t make much use of their individual results, some of these students aren’t seeing the value in recording that information. To give them a little more purpose, today we had some discussion to identify changes that could affect the motion of a hover disk on a ramp, then tasked them with collecting data to write a CER to answer how the change affects the motion. This will hit some points I wanted to get anyway, while also giving each group their own task using their data.
Chemistry Essentials: Gas Laws
Students made qualitative observations using sealed syringes in water baths. The ice machine in the school is broken, so the cold water tests didn’t work out very well, but we got some great results with hot water. A few groups had some trouble distinguishing between a change in pressure and a change in volume, so I wish we’d spent some time discussing how we could tell when the pressure in the syringe went up prior to the lab. However, by the end of the hour, groups were able to come up with qualitative descriptions of the ideal gas laws.
Students predicted which cart would experience a larger force for several different collisions, then we got out the force sensors and hoop springs to find out. In one of my classes, the computer was acting up, so we relied on the hoop springs and slow motion video. Fortunately, students found the video very convincing and even described watching the hoop springs compress as satisfying.
Physics: Video Physics
We started constant acceleration today. Students used photogates with a cart on a ramp during the first unit, so I decided to have students analyze hover disks on a ramp using Video Physics. I’m hoping that some of the features, like seeing the points in the video, will help students connect the representations we’re using to their physical meaning.
Chemistry Essentials: Thermal Expansion
I did a few demos of thermal expansion, and had students complete particle diagrams of each one. Students seem to be getting the big ideas, and I’m seeing students naturally improving how they represent key elements of their particle diagrams as time goes on. One student called me on falling into pretty teacher-centered habits during the whiteboard discussions; I have a tendency to talk to much the first time I teach a lesson, and this is my first time through Chemistry Essentials A, so that’s happening a lot. I need to spend a little more time during my lesson planning making sure I clarify the goal of each discussion and planning out some open-ended questions so I can give students more of the reigns.
Students whiteboarded their video analysis results for the trio of objects in simple harmonic motion. I haven’t done a lot of circular motion in the past, so when we discussed the spinning disk, I was intrigued by how many students were convinced the angle in the video was responsible for the changing velocity. On a whim, I had students sketch the disk from directly above, then had them sketch velocity vectors, including components, at a few points around the disk, which nicely convinced students that they would see similar graphs for the horizontal motion no matter what the viewing angle.
Earth Science: Problem Scoping
This unit includes an engineering project to plan removing a dam from a river. I gave students a memo from their imaginary client and had them do some problem scoping. One of the questions I ask is what background knowledge they will need, which can nicely set up a unit, but students did not identify anything about rivers or erosion as useful knowledge on this project. The memo mentions sediment transport as a major challenge in removing the dam, but I don’t think students saw that as something that would require background knowledge to understand. Even when I handed out the unit’s learning targets, students did not name the target about describing river behavior as one that will be useful. I need to think about how I will address that during the unit.