Day 31: Multiple Choice, Problems, & Bar Charts

October 18, 2017October 17, 2017 / Marta R. Stoeckel / 1 Comment

I was home sick today, so wasn’t able to take any photos.

AP Physics: Multiple Choice

Students worked on some multiple choice problems off practice AP exams. I usually have students answer individually with Plickers, then talk to each other and answer again before we have some whole-class discussion. To try and replicate that, I gave students two spaces to answer the questions so they can do all of them individually, then talk about each one with their group. I put in my notes to have some whole-class discussion about the answers at the end, which I’ll be curious to hear how it goes.

Physics: Problems

Students took the plunge to start calculations with constant acceleration. As part of their worksheet annotating graphs, I had students sketch and annotate v-t graphs given just the statement part of some of today’s problems. I’ll be curious to see if that is a useful bridge.

Chemistry Essentials: Bar Charts

Students worked on some bar charts for objects heating up and going through phase changes. We ran out of time to discuss the lab, so I ended up recording a video lecture that gives away the big ideas from the lab.

Day 30: Problems, Annotating Graphs, & Boiling Ice

October 17, 2017 / Marta R. Stoeckel / 1 Comment

AP Physics: Problems

Students worked on some conservation of momentum problems. When students asked for help, I could tell pretty quickly who had sketched interaction diagrams. Especially now that I’m embedding center of mass, they have become an incredibly powerful tool. I also demonstrated exploding carts on a balanced track and was pleased at how easily students used the center of mass of the system to explain why it stayed balanced, even when the carts had different masses.

Physics: Annotating Graphs

Students whiteboarded their solutions to yesterday’s problems. I’m pleased to see a lot of students starting to make sense of the physical meaning of the graphs. I was surprised by some students who struggled to differentiate between initial velocity and maximum velocity, but I think they were able to clear up their confusion by the end of the hour.

graph soln

Chemistry Essentials: Boiling Ice

Students recorded temperatures as ice melted and eventually boiled. A lot of students where quick to say their results didn’t make sense when they saw minimal temperature changes during the phase changes, which was great.

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Day 29: Conservation of Momentum, Annotating Graphs, & Temperature vs. Heat

October 16, 2017 / Marta R. Stoeckel / Leave a comment

AP Physics: Conservation of Momentum

We had a board meeting on last week’s conservation of momentum lab. As part of their whiteboards, I asked students to write a CER on whether their results made sense and encouraged them to use Newton’s Laws in their thinking. The 1st Law was a much more popular approach than the 3rd Law, but I was pleased at the connections were making.

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Physics: Annotating Graphs

Students started working on some problems to annotate velocity vs. time graphs and write equations for the area. I think this is helping some of my students to make more connections to what the graph actually represents, which will be an important stepping stone to solving problems. I also added some problems that just ask students to sketch and annotate a v-t graph from the kind of written description that would start a problem.

phys anno

Chemistry Essentials: Temperature vs. Heat

We took some notes on heat and temperature, then I asked students to predict whether there would be a larger temperature change when I added a small amount of boiling water or a large amount of warm water to a large beaker of room temperature water. Students seemed to wrap their heads around the difference and were able to explain why the warm water produced a bigger temperature change after the demo.

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Day 28: Conservation of Momentum, Mistakes Game, & Measurement

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

AP Physics: Collisions

After their quiz, students wrapped up the data collection on the collisions lab. Things went very smoothly, and a lot of groups have already commented on the pattern in their momentums. This is one of the times I love having quantitative uncertainty in the course, because students are independently deciding whether their momentums are close or effectively equal.

Physics: Mistakes Game

Students played the mistakes game with stacks of kinematic graphs. In class discussions, I’ve been struggling to get students to speak up and it is usually one or two students who do most of the talking after lots of long silences. Today, one of those students asked a question about the a vs. t graph, a member of the group presenting said, without any shame or fear, “We don’t really understand those graphs, so we just drew something.” All of the sudden, the whole class was animated and students who are normally quiet, even in small groups, were jumping in with fantastic questions. It was a fantastic way to end the week with that class.

Chemistry Essentials: Measurement

When I gave some notes on temperature scales yesterday, I had a student ask whether Kelvin is a more accurate scale than Fahrenheit and several others questioned it when I said 98.6 rounds to 100. I’m really excited about the thinking about measurement this shows, so I decided to lean in and do a Modeling Instruction measurement lab I’d skipped during the first unit. I had students measure the lab tables with popsicle sticks, gradually adding marks to make them more accurate. Next time, I think I will have them measure a bigger mix of objects, including some shorter than their tool.

Day 27: Collisions, Graph Stacks, & Linked Balloons

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

AP Physics: Collisions

Students started collecting data for the momentum before and after a series of different collisions to discover conservation of momentum. Several groups had a lot of trouble with what we meant by before or after the collision, which showed up as trouble both in filling out the table I gave them and in seeing how to place the carts and photogates appropriately. I wonder if having students draw an SOS diagram for the first collision would have helped with that.

Physics: Graph Stacks

We used the motion encoder to check the graphs students drew for objects on ramps earlier this week. Afterward, students started working on translating between our different representations for accelerated motion. A lot of my conversations with students today have me thinking that many of them are memorizing shapes of graphs without understanding what they represent. I need to keep working on ways to help students attach meaning to the shapes.

Chemistry Essentials: Pressure

I put a large balloon and a small one on opposite ends of a PVC pipe, using alligator clips to close both. Students sketched particle diagrams to predict what should happen when I removed the clips; I wish I’d had them write CERs instead to encourage more interpretation of the particle diagrams. After I showed students both balloons stays the same size, I had them do a second round of particle diagrams to explain why. There was some great conversation about pressure, but I think that phase also would have been better served with a CER.

Day 26: CoM Board Meeting, Breaking Down Problems, & Gas Laws

October 11, 2017October 11, 2017 / Marta R. Stoeckel / Leave a comment

AP Physics: Center of Mass Board Meeting

We had a board meeting to discuss the results of the video analysis from the last few days. I asked students to write a CER for whether the forces on each system of pucks were balanced or unbalanced. This lead nicely into some conversation about what exactly we mean by the two -puck system. I ended up wishing students had more experience interpreting position vs. time graphs prior to this discussion; we’ve mostly worked with velocity vs. time graphs so far, and the various uncertainties piled up to make it look like the velocity was changing. The position vs. time graphs were much more convincing, but students weren’t as likely to look at those.

Afterwards, we played with the coupled carts from Kaar, Pollack, Lerner, and Engles’ The Physics Teacher article. The graphs were very satisfying.

Top: v vs. t for each cart, Bottom: p vs. t for system

Physics: Breaking Down Problems

On the last quiz, a lot of students really struggled to interpret the problems, so we spent some time today on how to break down a physics problem. As we discussed how to approach a problem, we took time for students to apply each step to the problems on the most recent quiz.

Chemistry Essentials: Gas Laws

We used the results of yesterday’s simulation to develop the gas laws. I’ve found a lot of my students really struggle with algebra, so, rather than developing equations, we came up with statements using proportional reasoning which students then applied to some problems. Some of my students who really struggled to manipulate the density equation were very successful with today’s gas laws problems, so I think this approach was a success.

Day 24: Center of Mass, Ramps, & Gas Laws

October 9, 2017October 11, 2017 / Marta R. Stoeckel / Leave a comment

AP Physics: Center of Mass

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)

Physics: Ramps

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.

Day 23: Elevators, Board Meeting, & Pressure

October 5, 2017October 11, 2017 / Marta R. Stoeckel / Leave a comment

AP Physics: Elevators

I took some time today to introduce students to the CER framework. I showed them a force vs. time graph I made by riding the elevator with a mass hanging on a force sensor, then asked them to determine whether I was riding the elevator up or down. We haven’t done much with unbalanced forces yet, but they were pretty successful determining which direction I rode it.

Physics: Board Meeting

Students whiteboarded sketches of their graphs from yesterday. Its been taking longer and longer for groups to prepare whiteboards, so I think I will try setting a time on the SMARTBoard to try and speed things up. I also found a lot of groups were missing information we’d discussed recording prior to the lab yesterday, so I think we need to revisit lab notebook practices. The discussion was very abbreviated, so we only got a chance to discuss a little about the position vs. time graphs, but students were able to recognize the key ideas. On Monday, we’ll talk about the v-t graphs and look at some variations.

Chemistry Essentials: Pressure

To introduce pressure, students watched a balloon in a vacuum chamber, then whiteboarded what they thought was happening. Students were pretty successful at coming up with useful ideas to explain what they saw and inventing the idea of pressure.

Afterward, we boiled water in the vacuum chamber. We ran out of time to whiteboard it, but, on a whim, I got out my thermal camera and recorded a video to show the water stays cool.

Day 22: 3rd Law, Video Physics, & Thermal Expansion

October 4, 2017October 11, 2017 / Marta R. Stoeckel / Leave a comment

AP Physics: 3rd Law

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.

Day 21: Lab Practical, More Problems, & States of Matter

October 3, 2017October 11, 2017 / Marta R. Stoeckel / Leave a comment

AP Physics: Lab Practical

Students worked on a balanced forces lab practical to determine an unknown mass given the tensions supporting it. I just made one set-up, and it was interesting to see that in one class, each group wanted to take their own measurements, while the other class wanted to just have one person take the measurements and record them on the whiteboard. The hour that took measurements as a whole class actually took longer to get everyone the data, but had a lot more conversation about what they needed.

Physics: More Problems

I’ve got enough students struggling with constant velocity that we took a day to do a Modeling worksheet that I usually skip. Talking to students, there were several groups who thought the area of the velocity vs. time graph only gave displacement in special cases. I’m also seeing a lot of evidence that students are losing track of the physical meaning of the graphs and their connections with the math. For example, when writing an expression based on a graph, a lot of students are using units and variables from the dowel lab, which tells me they know a procedure to turn y=mx+b into “physics”, but don’t have a conceptual understanding of what they are doing. These challenges have been a recurring theme in physics this year; we’re starting constant acceleration tomorrow, and I think I want to revamp the lab a bit to try and prevent some of these issues.

Chemistry Essentials: States of Matter

Students melted ice into steam and made observations and drew particle diagrams along the way. This led nicely into the idea that as the temperature increases, the particles are moving more. Students also made some nice connections to yesterdays’ demo with food coloring in water.

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Motion