Day 18: Trig It Out, Dueling Buggies, & Density Problems

September 28, 2017October 11, 2017 / Marta R. Stoeckel / Leave a comment

AP Physics: Force Problems

Students worked on using vector addition diagrams to solve balanced force problems (one of many things I learned from Kelly O’Shea). I really like that while many of my students still ended up using a version of components, they see where the components come from. Once students set up their vector addition diagrams, the slogan for the day was “Trig it out!”, a line from last year’s students.

Physics: Dueling Buggies

Students worked on the Modeling Instruction lab practical to predict where two buggies will collide. I didn’t give quite enough instruction to my 1st hour, but once I suggested they try drawing some representations and play with them, they started making some progress.

One of my goals this year is to help students value ways of being successful in class besides knowing the answer quickly, so as part of the lab practical I gave them a list of skills based on similar lists from Kelly O’Shea and Ilana Horn, then asked them to identify at least one example for each group member where they demonstrated one of those skills. I’m looking forward to reading their responses.

Chemistry Essentials: Density Problems

Students worked on some density calculations. Some students really struggled with the algebra, so I’m trying to decide whether that really needs to be in the course. Most are getting to a point where they are successful with the graph, and I think that is more valuable in the long term than using the equation.

I also handed back the first quiz; most students performed about how I expected, but I was surprised at how many students had underestimated how they did and were genuinely excited about their score. Several confirmed with me (multiple times, in one case) that they got to keep their quiz so they could show their parents. I need to work on reinforcing the connections between our day-to-day work and the assessments so that more students will see that kind of success.

Day 16: Systems, v-t Graphs, & Good Questions

September 26, 2017October 11, 2017 / Marta R. Stoeckel / Leave a comment

AP Physics: Systems

Students did the mistakes game (pretty much my default mode of whiteboarding if you can’t tell yet) for a free-body diagram worksheet. Both classes had some great discussion about whether there should be an upward force for a projectile while it is in the air and it helped a lot to frame forces as interactions. I ended up wishing I’d taken some time to revisit Newton’s 1st Law from the momentum unit since some students were having trouble with the idea that forces are balanced on an object rising with a constant velocity. I’ll probably spend some time reinforcing that tomorrow.

I also took this opportunity to introduce students to the idea of defining their system. Both sections had debates about different problems where they were trying to decide what was causing an upward force. That lead nicely into discussing how we could define our system to make each possible answer correct.

Physics: v-t Graphs

Students worked on sketching velocity vs. time graphs based on motion maps and position vs. time graphs. The calculus class started v-t graphs at the end of last week, so I had some students who not only finished quickly, but were eager to exercise their new knowledge by helping their peers, which was great. I had a lot of students who struggled with the idea that the horizontal axis on the graph represents moving forward in time; I want to try getting out the motion detectors tomorrow so they can watch the graph form in real-time to see if that helps.

Chemistry Essentials: Good Questions

We spent some time working on asking good questions. I prepped a whiteboard with an intentional mistake, and asked students about what they saw. Some were able to use the question stems to immediately get to a good question. When a student had an observation or an idea of where to steer me next, I had them share it and we formed a question as a class. Then, we went back to the remaining student whiteboards and were much more successful and focused than yesterday.

Day 15: Rubber Bands & Mistakes Game

September 25, 2017October 11, 2017 / Marta R. Stoeckel / Leave a comment

AP Physics: Rubber Bands

Both sections worked on drawing interaction diagrams and free-body diagrams, but one of my sections is about 30 minutes ahead and was able to get the problems mostly done last week. That section had asked about what the graph looks like when a spring is overstretched and Hooke’s Law breaks down, so we got out some rubber bands to try. I told students I hadn’t had a chance to collect my own data, so we’d be finding out together, and they seemed on board with that.

Physics: CVPM Mistakes Game

Students played Kelly O’Shea’s mistakes game with Friday’s worksheet on translating between different representations of constant velocity. I really like this worksheet for introducing the mistakes game since its easy to direct students towards meaningful mistakes. I usually talk about some stems for good questions, but this time, I also projected them, which seemed to help. When the discussion lagged, I used Post-It notes to feed questions to students, but another student would usually ask the question I had in mind before I could finish writing, which is a good reminder to give them time.

Chemistry Essentials: Density Mistakes Game

This class played the mistakes game with Friday’s density problems. I also used the question stems with them, but they struggled a lot more with asking good questions. I think they need a little more scaffolding; I might put together a whiteboard and have students prep questions in their groups. A lot of students fell back into some of the behaviors I’ve been trying to push back against with the work on norms, and I think some of that was a result of some students feeling confused and frustrated with the discussion.

Day 14: Friction, Multiple Representations, & Density

September 22, 2017October 11, 2017 / Marta R. Stoeckel / Leave a comment

Today is homecoming, so classes are shot and students are excited.

AP Physics: Friction

I decided not to take the time for a lab on friction, so I collected some data with a force sensor and motion detector and asked students for observations. I used the motion detector to help connect what the force was doing to what we know about momentum so far. Students pretty readily recognized the force of friction changed when the block when from being at rest to being in motion.

Afterwards, students took their second quiz. Last year, I had very few students complete retakes, so this year I’m giving them at least two in-class attempts at each learning target to try and normalize reassessment. So far, I’m hearing a lot of talk from students that suggests they are much more comfortable with reassessing than last year’s students.

Physics: Multiple Representations

Students worked on a Modeling worksheet to practice translating between position vs. time graphs, motion maps, and descriptions of motion. Overall, students did well and I think this helped reinforce the value of what came out of yesterday’s discussion. In the class where I see the most struggles with math skills, several groups chose to shuffle themselves today, and ended up needing much less support from me than usual. For the first time, however, I had some students who made graphs showing multiple positions for a single point in time. I need to probe their thinking a little more and think about how to address that when we go over the problems on Monday.

Chemistry Essentials: Density

Students worked on a Modeling worksheet connecting particle diagrams and density. I got a little nervous when a very large group gathered around the para who assists the class, but they had some good discussions. I do need to think about how that will impact whiteboarding on Monday when 1/3 of the class worked as part of the same group.

Day 13: Board Meeting, Motion Maps, & Density

September 21, 2017October 11, 2017 / Marta R. Stoeckel / Leave a comment

AP Physics: Board Meeting

We whiteboarded the spring lab from yesterday. In both my sections, students had great observations and did a nice job of starting to talk about what the graphs mean with out too much prodding. There was a lot of great discussion about the limits of this model, as we tried to figure out whether the intercept on these graphs should be zero. One student also raised the point that if you overstretch a spring, it bounces back, so we was wondering if the linear relationship would still work. I might have them try it with rubber bands.

Physics: Motion Maps

We whiteboarded the buggy lab. I had a lot of trouble keeping students engaged in the large group discussion, I think partly because students didn’t use the ideas we developed in board meetings during the first unit, setting the tone that board meetings aren’t important. One thing that helped a lot was a student who was extremely willing to ask questions about what groups had done when their graphs were different from her group’s, which pulled a lot of students back into the discussion.

After the board meeting, I got out my Fridge Rover, a magnetic wind-up toy that maintains a pretty constant velocity, to introduce motion maps. I made marks on the board showing the rover’s position at regular time intervals, which drives home the connections between motion maps and the buggy lab students just did.

Chemistry Essentials: Density

Students found a relationship between mass and volume for water, which I used to introduce density. This was one of the times I really liked particle diagrams, since it made density much more concrete than an equation would. A lot of groups skipped finding the slope of their line, so I need to keep reinforcing that the slope is important.

Day 12: Springs, Buggies, & Board Meeting

September 20, 2017October 11, 2017 / Marta R. Stoeckel / 1 Comment

AP Physics: Springs

Students pulled on springs with force sensors to get data for Hooke’s Law. I usually have students who expect a horizontal spring to behave differently than a vertical one, so I took advantage of the force sensors to have students collect data for one of their springs in both orientations. When groups started to notice they have the same slope in both orientations, many of them started talking about whether that makes sense, which was fantastic.

Physics: Buggies

Students finished their data collection and prepped whiteboards for the buggy lab. One student came up to tell me he was thinking about how he could use the data from this lab. In particular, he wants to give the slow buggy a head start, then figure out where the fast buggy will pass it. I let him know that will be our next lab practical.

I’ve got a decent number of students who are struggling with math skills, such as finding slope or plotting negative values, and I need to adjust how I’m addressing that. I’ve been giving small group instruction as needed, but I’m spending a lot of time with just a few groups and missed others who were on the wrong track with this lab until pretty late. I’m toying with some options like providing math “cheat sheets” or having some mini lessons during the class for groups who need help, but I’d really like to develop a culture where students are relying on each other for some of that.

Chemistry Essentials: Board Meeting

Today went pretty smoothly; I think yesterday’s work on norms helped, though I need to make sure it doesn’t feel like a punishment next time. When I reviewed the norms at the start of class, a student asked if I actually like about teaching them, so I spent a few minutes sharing some examples of when I’ve really enjoyed their energy.

Students whiteboarded their results from this week’s volume lab. There are a big range of math skills in the class, but once groups compared the values on their data tables, they had an easier time getting at what the slope means. We hadn’t talked about the thickness of the sides, so I was excited when a student asked how it would change the results if the shapes were made of much thinner plastic.

Day 11: Uncertainty, Buggies, & Norms

September 19, 2017October 11, 2017 / Marta R. Stoeckel / 2 Comments

AP Physics: Uncertainty

We had a board meeting on yesterday’s force of gravity lab, and the discussion was better than I expected at this point in the year. As we were talking about the slope, one student claimed “Gravity doesn’t change”, which lead nicely into what we mean by that and how we know. In response, another student shared that yesterday one of her group members said “The force goes up 10 N for every 1 kg of mass”; after finally reading Arons this summer, one of my goals is to have students make “for every” statements about slope, and I was thrilled it came up naturally.

I also introduced uncertainty during the board meeting. Students had a lot of great observations about the relative precision of measurements and how much mass it took to change the reading on the scale, which gave them a sound conceptual basis. I rushed the discussion since the end of the hour was coming, and it ended up more teacher-directed than I’d like, but I’m pleased with how the basic approach worked.

Physics: Buggies

Students collected data for the buggy lab. Since when I ask for observations, there is usually a student who says the buggy is moving at a constant speed, I took a page from Michael Lerner and framed the lab as seeing how we can find out. A few groups are starting to make “for every” statements about their slope, which I did not see during the introductory unit and is great to see. I think the relationship is more obvious here than it was in the intro labs.

Chemistry Essentials: Norms

I’ve been struggling with classroom management. This is a very high-energy group, and there are a lot of things that are a lot of fun, but I’ve been having trouble keeping them on task and getting them to voices besides their own. I decided to pause today to spend some time developing norms as a class. I think a lot of students felt it was punitive, but many also agree that things aren’t working at the moment.

Day 10: Force of Gravity, Lab Practical, & Volume

September 18, 2017October 11, 2017 / Marta R. Stoeckel / 3 Comments

AP Physics: Force of Gravity

Students collected data to plot the force of gravity on an object vs. its mass. I had different groups use spring scales with two different ranges. Tomorrow, I’ll use the different levels of precision to motivate a discussion of uncertainty. Groups with the 50 N spring scale have already noticed that the smallest hanging masses don’t noticeably change the scale’s reading, which is exactly the kind of observation I was hoping for.

Physics: Lab Practical

Students revisited the dowel lab, this time as a group assessment. Their results on the original lab weren’t as good as I was hoping, but they are looking much better now that students have had an opportunity to discuss the flaws in their original approach.

Chemistry Essentials: Volume

Students found the volume of several different shapes, then measured how much water was needed to fill each one. Some groups got beautiful results, but other groups struggled. I think the groups that struggled had trouble matching up their measurements to the formulas on the cheat sheet I gave them or the Google calculators I showed them. A lot of students also also had trouble measuring the amount of water they put into the shape. The groups that struggled with these measurements were also the groups that were the least focused, but I’m not quite sure which issue is the chicken and which is the egg.

Day 7: Impulse, Ramps, & Particle Diagrams

September 13, 2017October 11, 2017 / Marta R. Stoeckel / 2 Comments

AP Physics: Impulse

Students graphed their data from yesterday. Since I was also introducing them to Desmos and my expectations for their lab portfolios, we ran out of time for the board meetings. The slopes are not coming out as nicely as I’d hoped, which I think is because this is their first quantitative lab and it always takes some time for students to get back into those careful practices. I’m trying to decide whether a different setup might be more forgiving.

Physics: Ramps

Students started collecting data to find a relationship between distance and time down a ramp. A major purpose of this lab was to give students an introduction to dynamics tracks and LabQuests, so we had them set everything up from scratch at the start of each hour. Most groups only got one or two data points, but they now see how pieces attach to the dynamics track and have a sense of how to use the LabQuests, so tomorrow should move pretty quickly.

Chemistry Essentials: Particle Diagrams

Students worked on a worksheet from the Modeling Instruction curriculum on drawing particle diagrams. I had to do a lot of prompting about what a particle diagram is supposed to show, so I need to think about how to help students connect the name for the diagram to what they should draw. I think students are also struggling to see why the particle diagrams are useful, so I need to think about how to solidify that.

Day 6: Impulse, Big Pendulum, & Alka Seltzer

September 12, 2017October 11, 2017 / Marta R. Stoeckel / 2 Comments

AP Physics: Impulse

Students did a lab I saw at a Modeling Instruction workshop over the summer. They connected a cart to a force sensor with an elastic string, and used motion detectors to produce velocity vs. time graphs. They collected data to make a graph comparing the area of the force vs. time graph to the change in velocity over the same time period. Introducing the lab felt pretty hand-wavy, so I need to think about how to do a better job of motivating the lab, but the data tables are looking good.

Physics: Big Pendulum

My big goal today was to motivate relationships besides linear. Since the data collected in the classroom for the pendulum lab tends to look pretty linear, I had students predict the period for a pendulum about 5 m long, then we went to a spot in the school where we could test it out. Since the period was shorter than expected, we started looking for other flaws in the linear fit, which lead to some good discussion on the intercepts of the linear graphs before we took a look at some other relationships and learned how to linearize.

Chemistry Essentials: Alka Seltzer

Today, I replaced beakers with plastic cups and we looked at the change in mass of Alka Seltzer in water before sketching some particle diagrams. Every group connected the fizzing in the water to the loss of mass, which lead nicely into the idea that gas has mass. There was some great discussion afterward; students were not only eager to ask interesting questions like what would happen if we had a way to trap the gas, they were also excited to share their ideas about what should happen and why. I usually start the second half of this course with a chemical reaction in a plastic bag to show conservation of mass, but I’m thinking about moving it up since it addresses questions that students are excited and curious about right now.