Day 64: LOL Diagrams, Elevators, & Volume

December 14, 2017 / Marta R. Stoeckel / Leave a comment

AP Physics: LOL Diagrams

We did the mistakes game again today (which my AP students now think of as standard whiteboarding in physics) for some problems with conservation of energy calculations. To avoid getting bogged down in the algebra, where most of my students are pretty strong, I had them put their mistake in the LOL diagram or writing the conservation of energy equation. Most groups worked on an accurate solution before they made their mistake, and one group did a nice job of setting up an equation for a problem where 10% of a baseball’s energy is dissipated before it reaches the peak of its path.

lol neat approach.jpg

Physics: Elevators

Students whiteboarded their work on Casey Rutherford’s elevator situations worksheet. A lot of students struggled conceptually with the direction of the net force, but seemed to resolve that by the end of the hour. I’m trying to lower the social risk of whiteboarding to get more engagement, so I gave each problem to two different groups, then had them meet and come to a consensus on a solution. Afterward, students did a gallery walk of all the whiteboards. We also discussed a video I made of a balance on an elevator to reinforce the worksheet.

Chemistry Essentials: Volume

Students filled geometric solids with water to find a relationship between the volume and the amount of water they could hold. I need to put some thought into how I introduce the lab; in particular, I don’t think my students have much concept of why this relationship is worth looking at. I know I can make use of that as we move into density, but I’m not sure how to frame the lab so they see a purpose in it up front.

Day 63: Conservation Problems, Board Meeting, & Reaction in a Bag

December 13, 2017December 13, 2017 / Marta R. Stoeckel / Leave a comment

AP Physics: Conservation Problems

Students started working on solving problems with conservation of energy. There was a fantastic moment when I overheard a student say “I don’t understand number 3 yet; I need to draw my LOL diagram.”

Physics: Board Meeting

Students discussed the results of the 2nd Law lab from earlier this week. I put more pauses into the whole-group discussion than usual for students to talk with their lab groups about some question and was very conscious of asking for claims the group, rather than the individual, had come up with and made explicit those claims were rough drafts. This seemed to ease some of the fears about speaking up.

Chemistry Essentials: Reaction in a Bag

Students reacted calcium chloride, sodium bicarbonate, and bromthymol blue in a Ziploc bag. to see another example of conservation of mass in a reaction that forms a gas. Next time, I might combine this lab with the Alka Seltzer one to make a more involved exploration of whether gas has mass. Aside from this feeling more like a true chemistry lab than the Alka Seltzer one (students definitely connect goggles with “real” chemistry), that may give the opportunity to go into questions such as which was the better method of capturing the gas or whether all or some gasses have mass.

Day 63: Bar Charts, Board Prep, & Particle Diagrams

December 12, 2017 / Marta R. Stoeckel / Leave a comment

AP Physics: Bar Charts

Students whiteboarded yesterday’s problems for the mistakes game. In both my classes, students were generally excited to do the mistakes game and I contributed almost nothing to the discussion, which was fantastic. Afterward, we took a few minutes to use some thermal camera images to see examples of energy dissipated by friction, including a photo I took of my car after driving it.

Physics: Board Prep

I’d planned to have the board meeting today, but we ended up just prepping whiteboards today since enough groups had issues with their data that I think it would have been tough to have a good discussion. I tended to let poor data slide last tri, since it was easy enough to recover during the board meeting, but I think a lot of groups are counting on being “that” group during the discussion. I think having those groups re-do their data collection today helped set the expectation that they shouldn’t plan on being “that” group.

Chemistry Essentials: Particle Diagrams

Students worked on a worksheet to practice drawing particle diagrams. The students who’ve been engaged in the labs so far were able to breeze through the worksheet and had some good discussions along the way. I’ve got more students than last tri, whoever, who checked out during those activities and had a lot of trouble with the worksheet as a result. I need to think about how I will interrupt the vicious cycle that is starting for those students.

Day 62: Systems, Newton’s 2nd Law, & Does Gas Have Mass

December 11, 2017 / Marta R. Stoeckel / 1 Comment

AP Physics: Systems

Students worked on a Modeling Instruction worksheet that emphasizes how changing the system changes the LOL diagram. A lot of students very naturally connected this to the SOS diagrams we’d done earlier in the year and how changing your system can affect whether there is any impulse.

Physics: Newton’s 2nd Law

Students used a half-Atwoods machine to collect data for how the force on a cart affects its acceleration. I ended up wishing I’d spent a little more time on the pre-lab; a lot of groups lost track of what they were measuring and how that connected to the purpose of the lab. Since I’m seeing low engagement during whole-class discussions, I’m thinking about how I could have students do some of the pre-discussion in their lab groups, instead.

Chemistry Essentials: Does Gas Have Mass

Students measured the mass with a reaction of water and Alka Seltzer to decide whether gas has a mass. They did the reaction once in an open test tube and once with a balloon on top. While the balloon clearly leaked, there was significantly less loss of mass with it in place. I didn’t ask for particle diagrams on the lab handout, but I think that would have helped students think through what they expected and why.

Day 61: Bar Charts, Mistakes Game, & Burning

December 8, 2017December 8, 2017 / Marta R. Stoeckel / 1 Comment

AP Physics: Bar Charts

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.

Day 60: Kinetic Energy, 3rd Law, & Melting Mass

December 7, 2017 / Marta R. Stoeckel / Leave a comment

AP Physics: Kinetic Energy

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.

Day 59: Energy, 3rd Law, & CER

December 6, 2017 / Marta R. Stoeckel / Leave a comment

AP Physics: Intro to Energy

Students measured the average force and the displacement required to give a cart the same change in height on several different ramps. They sketched the force vs. displacement graphs, which I used to introduce gravitational potential energy and work.

Physics: 3rd Law

We ran out of time to hit Newton’s 3rd Law during last tri’s unit on balanced forces, so today we dove in. I showed students a pair of carts, then asked them to draw interaction diagrams and free body diagrams for various collisions, as well as to predict which cart will experience a larger force. One group gave me a hard time about how deadpan I was when they asked if their prediction was right, so we talked a little about Clever Hans the Math Horse.

Chemistry Essentials: CER

As part of the follow-up on yesterday’s lab, I introduced students to the CER framework. I had students identify the claim and evidence in a car commercial, then come up with some potential reasoning for the evidence before they started a CER on whether the mass of steel wool should change.

Day 109: Collision Types & Testing Round 2

February 28, 2017July 14, 2017 / Marta R. Stoeckel / Leave a comment

AP Physics: Collision Types

Students worked some problems using elastic vs. inelastic collisions. They are feeling very confident about energy, which is great to see, and several students are thinking about how they could use energy to work problems we’d done earlier in the year, which is fantastic.

As a side note, registration for our AP exams ends tomorrow, and I’ve offered doughnuts to the first class to get 100% registered. Its been surprisingly effective and I’ve currently got the highest registration rate. I need to remember to give the same challenge next year.

Physical Science: Testing Round 2

Students tested their second design. There was a nice variety of tests, including one group that had a tray of ice at the bottom of their ramp to simulate weather conditions. Most groups tried at least one collision besides the head-on we’d done before. One group asked if they could use bubble wrap to simulate a bumpy road. While the trucks are heavy enough that I don’t think the bubble wrap did much, I like the idea and am thinking about what might have worked better.

Since we only have four ramps, I assigned groups with similar tests to the same stations and directed them to figure out how they would share the equipment. It was more chaotic than the first round of testing, but that’s to be expected. I might scaffold them a little more on making that plan next year.

A bumpy road

Rear-end collision

Day 108: Collision Types & Building Again

February 27, 2017July 14, 2017 / Marta R. Stoeckel / Leave a comment

AP Physics: Collision Types

We whiteboarded the results of Friday’s Direct Measurement Videos to get to the definitions of elastic and inelastic collisions. A lot of groups tried to answer purely conceptually, in spite of some quantitative questions on the activity. I think these groups were treating each question as separate, rather than thinking about how one answer could help them with the next piece of the activity. I want to make better use of lab notebooks (most likely starting next year) as a reflective tool, which I think might help students see more connections between problems.

ap-wb

Physical Science: Building Again

Students worked on their second round of building. I upped the cost of paper cups, which were the most popular material on the first go around, which lead to a little more variety in egg holders. I also did another round of visiting each group and asking them to explain their design choices using Newton’s Laws, and I can tell students are getting more confident with this skill.

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Day 107: Collisions & Test Design

February 24, 2017July 14, 2017 / Marta R. Stoeckel / Leave a comment

AP Physics: Collisions

Students use a pair of Direct Measurement Videos, one of a collision between two billiard balls and one of a heavy disk tossed onto a cart, to explore changes in momentum and kinetic energy in the collisions. I haven’t done as much with uncertainty as I’d like, so I was very pleased with how clearly students were talking about it to decide if their values were “close enough.” I had students sketch momentum SOS and energy LOL diagrams, but students weren’t paying as much attention as I’d hoped to whether there were any dissipative forces present, so next year I want to do a better job of getting students into that habit. I was thrilled, however, when a student used some proportional reasoning to convince herself that you cannot conserve momentum and keep a constant kinetic energy when the objects are moving together after the collision. I was also pleased by how many students were interested in trying to explain the billiard ball that just spins in place right after the collision.

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Physical Science: Test Design

Students began working on designing a second iteration of their cargo carriers. To encourage new designs, I increased the cost of paper cups (the most popular component on the first round) and shuffled groups. We also talked about the limits of testing just the front-end collisions, and tasked students with coming up with their own tests for this round. The discussion was a little trickier this year than in the past; we dramatically upgraded the trucks the cargo carrier attaches to this year and the old trucks would pretty reliably tip over or roll off the side of the ramp at least once per class, which gave a nice tangible example of the test’s limits. That didn’t happen at all this time, so next year I might take off the rails we put on the side of the ramps to try to encourage some failed tests.