Students worked on developing Kirchoff’s Laws this week. We started with PhET’s circuit construction kit, then got out the power supplies and resistors. Some groups had trouble recognizing the simulation and the physical lab as addressing the same concepts, but explicitly asking groups how their results compared seemed to help students make the connections. There was also some good discussion about why the results in the physical lab didn’t match the simulation exactly. A thermal photo showed some heat at the alligator clips, which lead to some conversation about whether the wires we were using were ideal.
Physics: Energy Transfer Card Sort
This week we worked on starting energy conservation problems. To help the transition from bar charts to problems, I turned some problems Kelly O’Shea and Mark Schober wrote for the New Visions physics curriculum into a card sort. Seeing cards with two versions of the conservation of energy equation seemed to help a lot of students see how to build equations from the bar charts, which made the problems much smoother than in the past.
This week was mostly about working problems for simple harmonic motion. I kept the focus on representations, including free-body diagrams, energy bar charts, and motion graphs, which made it a good review of a lot of mechanics topics. I also was really pleased when a student was checking out the topics we have left to cover on the AP Physics 1 Your Course at a Glance and asked if our unit on mechanical waves will have anything to do with the simple harmonic motion we’ve been working on.
Physics: Momentum Card Sort
This week, we worked on transitioning to calculations with conservation of momentum. We started with a collision lab from the Modeling Instruction curriculum, then did Kelly O’Shea’s momentum representations card sort. I’ve had a lot of students asking for me to do example problems before they work problems on paper, which I try to avoid. The card sort seemed to fill that need for a lot of students, while keeping the focus on their sense-making. I definitely want to work on a similar card sort for energy.
This post has ended up a few days late. But I still have yet to miss an intended post on this blog!
Physics: Unbalanced Forces
Students did the classic Newton’s 2nd Law lab with a half-Atwoods machine, then we started fitting net force with the diagrams we’ve been working on. The first set of problems we typically do is just sketching diagrams. This year, we decided to try turning it into a card sort, which I think really helped students who were new to me transfer their knowledge of force diagrams into my classroom, something I’d been thinking about leading into the term. I also pushed using motion maps with acceleration arrows much harder than I have in the past, and one of the results was I got almost no questions this week about which direction the net force should be in.
AP Physics 1: Conservation of Momentum
We wrapped up the momentum transfer model (at least for now) by working on conservation of momentum. Students were very excited about Michael Lerner’s watermelon on wheels problem. Aside from being silly, I really like that it pushes students to play with viewing a single scenario with multiple different perspectives. We also did a little bit with momentum bar charts, since they show up in the AP Physics 1 workbook we did a few problems out of, and I found they really helped a lot of my students. I need to make much more use of those bar carts next year.
This was a three-day week since public schools closed on Thursday and Friday for the state teachers union conference.
AP Physics 1: Vector Addition Diagrams
Students started the week by doing Kelly O’Shea’s forces representations card sort. I used the card sort to introduce vector addition diagrams, and students easily recognized key aspects of the VAD. The rest of the week, we worked on applying VADs to solve problems. They are successfully applying the VADs, but aren’t feeling confident in their skills just yet.
Physics: CAPM Practical
After wrapping up some problems using the constant acceleration model, students started working on a practical to figure out where to start a marble on a ramp so that it lands in a passing buggy. We ran out of time for students to test their calculations. While students made good progress, many are uncertain of their skills; I’m hoping that completing the practical on Monday will help them build confidence.
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.
Students collected data for variables that affect the period of a pendulum. This was a day where I could tell students are getting better at experimental design and more comfortable with being independent; groups were able to work through challenges and surprises with very little input from me.
Physics: Projectile Graphs
Students whiteboarded their results from yesterday’s activity in Pivot Interactives. They had to shake some of the dust off their skills on interpreting motion graphs, but it came back quickly and students made the connections I was after very successfully.
Chemistry Essentials: Periodic Table Card Sort
Students worked on a card sort to introduce the periodic table. A few students were really eager to know what some of the features of the cards represented, which lead to some great conversations in lab groups about patterns they saw with those numbers.
AP Physics 1: Energy Bar Chart Mistakes Whiteboarding
Students did mistakes whiteboarding with energy bar charts. There was some good discussion about what differences matter in energy bar charts at this point and what differences, like the exact number of boxes, are irrelevant.
Physics: Momentum Card Sort
Students worked on a momentum transfer model card sort I got from Kelly O’Shea. I was (pleasantly) surprised by how easy it was for students to work out which equation went with each problem. The force-time graphs in the card sort were tough; part of the trick is those graphs are more similar across different problems than some of the other graphs and we haven’t made enough use of force-time graphs in other contexts for students to focus on the subtle details that distinguished the different graphs here.
Chemistry Essentials: Density Mistakes Whiteboarding
This class also did mistakes whiteboarding, but on a worksheet using different representations for density. There was some great discussion and some signs this group is starting to build an identity as a class, which is great.
Students worked on Kelly O’Shea’s balanced forces card sort. Since they haven’t seen vector addition diagrams yet, I tried holding those back until they’d sorted everything else, which worked really nicely. I was also much stricter than I was in my regular physics that students needed to sketch the interaction diagrams, and that seemed to really help students think through each scenario.
Physics: Board Meeting
Students whiteboarded their results from Thursday’s lab on Newton’s 2nd Law. My 1st hour got pretty nice results, including slopes that came out very close to the masses of their carts, but my 6th hour had much messier data. I ended up telling students to focus on a few specific whiteboards when we were talking about some key points, which seemed to work out fine.
Chemistry Essentials: Formula Writing
We started working on writing chemical formulas. I had students sketch simplified Lewis dot structures on whiteboards, then use beans as manipulatives to figure out the correct chemical formula. The students who took the time to sketch and use the diagrams were very successful at thinking through the formulas I threw their way.
Students worked on Kelly O’Shea’s CAPM card sort. First, they did the most basic sort they could using just the graphs. Next, they did a sort using their physics knowledge with just the graphs. Once groups had a physics-y sort they were happy with, I gave them the word cards for a third round. I liked how the progression went and there was a lot of good discussion along the way.
Physics: Vector Addition Diagrams
Students worked through an activity from Casey Rutherford using pipe cleaners to make manipulative vectors and rearrange free-body diagrams into vector addition diagrams. I really like the way this activity drives home that forces can be balanced even if they are not equal, but it is a pain in the neck to get the pipe cleaners nice. I might try to make a version using Brian Frank’s vector manipulatives for next year.
Chemistry Essentials: Rutherford
Students simulated Rutherford’s experiment by rolling a marble towards a set of hidden marbles and tallying how many times they hit something. In the past, I’ve had students calculate the diameter of their target marble, but the math is always kind of a black box. This year, I’m having students do the lab once with big marbles as the target and once with small marbles as the target in the hopes of keeping the focus on the key ideas.
Students did mistakes whiteboarding using yesterday’s problems. To keep us from getting bogged down in algebra, I had students put their mistake in the diagrams or annotations, then we focused the discussion on getting those parts right and I posted final answers to the class website. Dropping a negative sign was a very popular mistake today, but a lot of students have been making that error, so it was a good one to work on.
Physics: Spring Force
Students finished data collection for the spring force lab. I like to have students collect data for the spring both when it is vertical and when it is horizontal to get the idea that the orientation of the spring does not affect its spring constant.
Chemistry Essentials: Card Sort
Students worked on a card sort based on how Mendeleev worked out his periodic table. I skipped having students do a gallery walk of how other groups sorted their cards before seeing a periodic table, and I wish I’d taken the time to do so since I think it would have gotten students thinking about other ways to sort.