This week, students worked on applying conservation of energy. We wrapped it up with a lab practical to find the spring constant of a popper toy. To help with what makes a good procedure, I had groups start by writing out the steps they were going to follow on a whiteboard. Then, they traded whiteboards with another group and had to follow the procedure they were given to actually collect data. One group came up with a nice strategy of writing out the equation they’d use in their calculations, then checking off each variable as they added a step to measure it.
Physics: Pushing Boxes
Students spent a lot of time this week on problems applying Newton’s 3rd Law and synthesizing Newton’s Laws, including some great problems originally from Matt Greenwolfe where students draw free-body diagrams and velocity vs. time graphs for boxes pushed across various floors. While there was some great discussion, I think these problems would have been more valuable much earlier in the forces model. In general, I think Newton’s 3rd Law feels like an afterthought in how we approach forces. With some shifts in what we’re doing early in this model, we could better integrate key elements of this model and reduce the need for doing some kind of synthesis at this point in the unit.
Students worked on sketching bar charts and LOL diagrams to show energy transfers. I was really pleased with how comfortable students were switching between different systems. I started out the week by having students use a spring scale to pull a cart up different ramps, always raising their cart to the same height above the table. We then sketched force vs. displacement graphs to introduce the idea of work and gravitational potential energy. Getting both simultaneously meant the concepts blurred together for students at first, but that issue got resolved as we did mistakes whiteboarding with energy bar charts and LOL diagrams.
Physics: Newton’s 3rd Law
One of our major tasks this week was developing Newton’s 3rd Law. Students started by predicting how the forces on two colliding carts would compare, then we tested out the collisions. As we tested the collisions, I cued students to notice the relative accelerations of the carts, which I think helped students see the useful thinking in their original predictions. Before we officially stated Newton’s 3rd Law, I borrowed an idea from Mark Schober and had students play with film canisters with magnets inside to test and refine their rule before the whole-class discussion.
This was another short week. Parent-teacher conferences were on Thursday night, so Friday was scheduled as a professional development day.
AP Physics 1: Newton’s 3rd Law
This week our focus was on Newton’s 3rd Law. Students predicted which cart would experience a larger force during various collisions, which we then tested using a pair of carts with force sensors and hoop springs. In my grad class this semester, we’ve been doing a lot of talking about the ways language students use can mask meaningful understanding, which got me thinking about how I can make better use of students’ predictions. This year, I tried being very explicit that our task was to find the useful ideas in students’ predictions and to translate those useful ideas into the language physicists use. There was a great moment where a student said “So the force and the result of the force are different things, but we were treating them as the same”, which I couldn’t have planned better.
I also took a page from Brian Frank this week and used some magnetic hooks for an easy setup of a static forces lab practical.
Physics: Newton’s 1st Law
This week was about developing the idea of a force and Newton’s 1st Law using interaction stations and the bowling ball lab. A few students were resistant to actually trying the bowling ball lab this year, rather than actually testing whether what they expected worked, so I had to push some groups to really explore getting the bowling ball moving with a constant speed. Once they got started, however, there was some great discussion.
Today was the last day to submit work or complete retakes before the end of the term and our last day of classes before Thanksgiving break, so it was a very chaotic day.
AP Physics 1: Whiteboarding
Students wrapped up presenting the whiteboards from yesterday. There was some really great discussion, with students making use of the matter model and connecting to the collisions we’d tested out a few days ago.
This class also worked on wrapping up whiteboarding some problems. My 6th hour had a really tough time focusing, which was not surprising the last hour of the day before a break. While we still got where we needed to, I don’t think a whiteboard discussion of problems was the right call for today.
Chemistry Essentials: Quiz
Students took their quiz on naming and formula writing for ionic and covalent bonds. Since it was fairly short, we spent some time before the quiz whiteboarding a few practice problems. A few students were focused on last-ditch efforts to raise their grade, and it was tough to re-direct them to the day’s activities. This will be something to think about at the end of next trimester.
We started looking at some force problems involving Newton’s 3rd Law by doing some mistakes whiteboarding. There was a lot of good discussion on the directions of normal forces in problems where the normal doesn’t just go straight up.
Physics: Mistakes Whiteboarding
This class also did mistakes whiteboarding, even with the same problems as in AP. Once again, there was a lot of good discussion on the direction of the normal forces.
Chemistry Essentials: Binary Compounds
Students practiced translating between names and formulas for binary compounds. Most students took to this pretty quickly and easily, which was great to see.
Students worked some problems on balanced forces, with an emphasis on Newton’s 3rd Law. We also started talking a little bit about the final exam, which will be a modified practice AP exam.
Physics: 3rd Law
Students predicted how the forces would compare during a series of collisions, then we tested teach collision out using a a pair of force sensors with hoop springs attached. Partway through the testing, a few students made the connection to Newton’s 3rd Law, which was fun to see.
Chemistry Essentials: Covalent Bonds
I introduced students to covalent bonding today. We aren’t going into much depth on figuring out the formulas, but we did take some time today to sketch electron diagrams (simplified Lewis dot structures) to get at what is going on during a covalent bond.
Students predicted the relative forces on two carts in various collisions, then we tested them using a pair of carts with force sensors. I really like using hoop springs for this since it gives a very clear visual in addition to the force vs. time graphs.
Students whiteboarded the problems they worked on yesterday for a gallery walk. We set up the packet to re-use the problems we had that just deal with representations.
After discussing the problems, I showed students a video I’d recorded on our elevator and asked them to write a CER for whether I took the elevator up or down.
Chemistry Essentials: Polyatomic Ions
We added polyatomic ions to the formula writing we’ve been doing. Students seem to be getting the hang of how to figure out the formula. Some students have figured out the “flop and drop” strategy, and others are opting to draw the simplified Lewis dot structures we’ve been using when they get stuck.
The approach I’ve fallen into in order to give students time for their final projects while embedding some review for the students who will be taking the AP Physics 1 exam on the make-up date. Today, I got out a globe that floats in a magnetic stand and asked students to predict what should happen to the reading on a balance when the globe is removed, an idea I got from Kelly O’Shea. One group did a thought experiment where the magnet was replaced with a spring supporting the globe to reason their answer and had a great conversation.
Physics: Pinhole Viewers
We discussed some of the results of yesterday’s lab, focusing on how a ray diagram can explain the observations students made. Students are pretty quickly getting then hang of making sense of these diagrams.
Chemistry Essentials: Hollow Pennies
Students did a conceptual lab practical on activity series today. I gave students an activity series for metals, then asked them to predict whether copper or zinc is more likely to react with hydrochloric acid. Then, I gave each student a penny with a wedge filed into it to test their prediction. I also showed students the hollow remnants of a penny that had been left in 12M hydrochloric acid for a few hours.
We discussed the results of yesterday’s lab in order to define kinetic energy, then I showed them the derivation for elastic potential energy. Since we’d already defined change in potential energy as the area of a force vs. displacement graph, I think I could have put that derivation on students. Afterward, I introduced students to LOL diagrams and set them to work sketching bar charts.
Physics: Mistakes Game
I love Kelly O’Shea’s mistakes game, but I’ve been having trouble getting my physics students comfortable talking as a whole class, so I decided to try lowering the stakes. I had them prep whiteboards as usual, but then they presented to another group, rather than the whole class. There were a lot of great conversations between groups and students were much more comfortable speaking up. Afterward, I gave students time to do a gallery walk of the post-discussion boards.
Chemistry Essentials: Burning
Students burned steel wool on a balance to observe the change in mass. Afterward, we used Post-It notes to make histograms of the change in mass from both yesterday’s labs and the burning. Last trimester, I skipped the class histograms, but I think the helped this group to meaningfully interpret their results. I also got excited when a student brought up conservation of mass before I did, which I don’t manage as often as I’d like in this course.
To introduce kinetic energy, I had students work through a Pivot Interactives activity to find a relationship between the starting height of a puck and its velocity at the bottom of a ramp. I ran out of time to have a pre-lab discussion yesterday, so tried to have one in the computer lab today. I had more students then usual struggling with what to measure or what to graph, and I think that was because a lot of them started the activity rather than fully engaging in the discussion. Once they got rolling however, students warmed up to the interface pretty quickly.
Physics: 3rd Law
We collided carts with force sensors to check the predictions students made yesterday. I spent more time than usual talking about why I asked them to make predictions I know are likely to be wrong since confidence has been such an issue for students this year.
Chem Essentials: Melting Mass
Students continued the Modeling Instruction mass and change labs. Today, they melted ice and mixed sodium carbonate with calcium nitrate; a lot of students really liked that reaction and were observing close enough to notice the precipitate causing the cloudiness. I added a mini-exploration of the zero button on the balance, which I was pretty happy with. A lot of the students in the course struggle with mathematical reasoning, and taking a few minutes to play with the zero button and the readings on the balance seemed to help make its purpose more concrete.