Day 2: Buggies Redux, Dowels, & Coffee Can

AP Physics 1: Buggies Redux

Today we repeated the buggy lab, but with a focus on preparing whiteboards that would make a meaningful comparison across groups. I had each group collect data for a standard buggy moving forward from zero and one other variation. One thing I’m really excited about is several groups played with ways to represent multiple trials on a single graph and one group came up with Frank Noschese’s effortless error bars on their own, which will be a great introduction to uncertainty.

Physics: Dowels

This class is also doing two rounds of the first real lab. Today, I asked students to use a bunch of small dowels to collect data that would let them predict the mass of a much larger dowel made out of the same type of wood and represent their data on a whiteboard. The majority of groups used proportions, which was great, but very few measured multiple small dowels on their own and no one thought to try a graph. In most labs, I ask students to find a relationship, and I wonder if that would be a more interesting prompt here.

Chemistry Essentials: Coffee Can

We did the exploding coffee can demo to introduce particle diagrams. I had a few students who were really willing to propose ideas to explain the changes in the can’s behavior as the flame burned, which was awesome.

coffee can

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

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 9: More F-t Graphs & Board Meetings

AP Physics: More F-t Graphs

We discussed some of yesterday’s problems. To help with a few of the conceptual problems, we got out the force plate and had someone jump, once with their knees stiff and once bending their knees as they landed. Looking back, I wish I’d started this week’s impulse lab more qualitatively to set them up for some similar realizations to the ones we had today.

impulse jump

Physics: Board Meeting

We had a board meeting for this week’s ramp lab. I struggled a bit with what I wanted students to have as their takeaway since we are still on an introductory unit, and the discussion suffered a bit as a result. The other physics teacher had his students focus on a qualitative relationship between ramp angle and slope, and was happy with how things went, so I need to do a better job of identifying opportunities like that if I do a similar intro unit next year. On Monday, however, we are on to actual physics!

ramp wb

Chemistry Essentials: Board Meeting

Students whiteboarded their particle diagrams for yesterday’s lab, along with a CER for whether a gas has any mass based on this lab. They did a nice job on preparing the whiteboards, but the class discussion was tough; a lot of students had trouble staying focused on the conversation at the end of the day on a Friday. I usually keep my class norms pretty broad, but I think it would be worth having the class develop some more specific norms for class discussions.


Day 8: Board Meeting, Ramps, & Mass of a Gas

AP Physics: Board Meeting

We had a board meeting on this week’s impulse lab. I had one section where about half of the groups changed the mass of their cart for each trial, so I need to make sure I revisit experimental design concepts, like how to tell what variables should remain constant. Students still recognized all of the relevant patterns and we were able to get to the impulse equation nicely.

Physics: Ramps

Students finished collecting data for distance and time down a ramp to see a quadratic relationship. The results weren’t as clean as I hoped, largely because a lot of groups started their cart a fair distance behind the first photogate. It takes some background knowledge to understand why that matters, and with the cognitive load required to learn to use the photogates and set up the dynamics track, they lost track of that detail. If I do a graphing unit next year, I might give more traditional written directions rather than relying on discussion and expecting students to make the notes they need to help ease them in a little more.

Chemistry Essentials: Mass of a Gas

Earlier this week, a student asked what would have happened with the dissolving Alka Seltzer if we had a way to trap the gas and the rest of the class was very excited to discuss their ideas. Today, to answer that question, I had them mix calcium chloride and sodium bicarbonate, along with some indicator, in a Ziploc bag. Things were chaotic enough that I didn’t get much chance to listen to students reason about the reaction, but part of the chaos was a lot of groups were excited to tell me about their observations, which was a great kind of chaos to have.


Day 7: Impulse, Ramps, & Particle Diagrams

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.impulse wn

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

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.

pendulum big

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.


Day 5: Mistakes Game, Pendulums, & Dissolving

AP Physics: Mistakes Game

On Friday, as students finished the FCI, they picked up some problems translating between momentum vs. time graphs, motion maps, and written descriptions. Today, we went over them using the Mistakes Game. ┬áStudents pretty readily embraced this approach, which was great to see. I did notice a lot of students were not clear on whether arrows between the dots on a motion map represent the momentum vector or a “tap”, which I think goes back to how I introduced the bowling ball lab. Asking students about the spacing on the motion map got them to think about whether there should be a tap, which seemed to help.


Physics: Pendulums

Students worked on finding a relationship between the length and period of a pendulum. On Friday, we’d measured a single period as a class to motivate the need to measure multiple periods. Today, I verbally reminded students of that discussion, but, once in the lab, a lot of students were unclear about what it meant to measure multiple periods; I think it would have been useful to demo that to help with their language. Most groups were able to get a graph done, and have done a linear fit with a nice big intercept, which will lead nicely into motivating the need for other relationships tomorrow.


Chemistry Essentials: Dissolving

We continued the mass and change sequence from the Modeling Instruction chemistry curriculum. My plan was to get through both sugar and Alka Seltzer dissolving in water, but I wasn’t thinking when I grabbed beakers this morning and ended up with way more mass than the balances could handle. I ended up having my students do a lot of math, which many found overwhelming, especially since they had to add some blanks to the handout I’d made. If I’d been thinking, I would have pulled out some lightweight plastic cups to replace the beakers. Tomorrow, I’ll use those for the Alka Seltzer lab.

Day 3: Motion Detectors, Board Meeting, & Burning

AP Physics: Motion Detectors

This concept development sequence comes from conversations with Michael Lerner, Kelly O’Shea, and the rest of the Physics! PLC!

One of the tasks I gave students yesterday was to sketch a momentum vs. time graph for getting a bowling ball moving, then reversing its direction. There was a lot of disagreement about what that graph should look like, so today we had some brief discussion about how the momentum vs. time graph should compare to the velocity vs. time graph, then got out motion detectors and billiard balls to try some of yesterday’s tasks. The discussion afterward lead very nicely into the significance of a negative momentum, as well as the meaning of the slope on a momentum vs. time graph.


Physics: Board Meeting

We had a board meeting for the dowel lab, following Casey Rutherford’s Observations, Claims, Evidence structure. Even though all of the dowels were made of the same material, slopes were all over the place, so we had some discussion about how to improve the results next time. A lot of groups just wrote down their calculated volume, rather than the values they measured, which made it difficult to check their calculations, so we discussed the value in recording the measured values.

hour 2 summary.jpg

Chem Essentials: Burning

We continued the mass and change experiments, which today included burning steel wool. I needed to do a better job of framing this lab as being about the mass of the steel wool. A lot of groups missed recording the initial mass before they lit the wool, which I could have addressed by checking they had that value before giving them any matches. I also saw a lot of groups blowing on their wool or tossing used matches onto the dish with their wool, which reinforces that they were not thinking about the mass as important here.

steel wool

Day 2: p vs. t Graphs, Graphing, & CER

AP Physics: p vs. t Graphs

This concept development sequence comes from conversations with Michael Lerner, Kelly O’Shea, and the rest of the Physics! PLC!

There was still some debate from yesterday about whether the bowling ball had a constant speed after a tap, so I pulled out the Motion Shot app to make a motion map. Afterwards, students did a variation on the bowling ball lab with combinations of taps to introduce momentum vs. time graphs. I picked a few scenarios to help them get the idea of negative values for force and momentum as well as some to get at the significance of a non-zero intercept on the graph.


Physics: Graphing

Students worked on their graph for the dowel lab, then we talked about “translating” the equation for the line of best fit by adding units and variables appropriate to the quantities they graphed. Students seemed to do well wrapping their heads around that step. Tomorrow, I’m going to have them write the slope as a statement a la Arons.

I’m also thinking about repeating the data collection tomorrow. Students are getting a wide range of slopes and intercepts and, if we’re going to take the time for a unit on experimental design and graphing, I’d like to establish careful practices right off the bat.

Next year, it could be interesting to mess with the calibration of the triple beam balances to give a non-zero intercept. I’m not sure yet if I would do that immediately, or if I would do a second round of data collection with the balances off.

dowel lab

Chemistry Essentials: CER

I put a CER at the end of yesterday’s lab, and students seemed pretty thrown by the reasoning piece. Today, I played the “My Dad’s an Alien” commercial and had students identify the kid’s claim and some of her evidence. Then, students got into their groups and had to fill in the reasoning for at least one piece of evidence. A lot of groups looked at why she might see something as evidence (like why the car seems like a spaceship), as well as why the evidence might support the claim. Yesterday, I felt like I was struggling to keep students on track, but today they were very engaged and even enthusiastic about the task. I think today I was much clearer about what they should be doing and what that looks like.

alien cer

Day 1: Bowling Balls, Dowels, & Steel Wool

The first day of school is in the books!

AP Physics: Bowling Balls

This concept development sequence comes from conversations with Michael Lerner, Kelly O’Shea, and the rest of the Physics! PLC!

I’m starting the year with momentum, so the first idea I want students to build is the impulse-momentum theorem. Today, we started with a version of Frank Noschese’s bowling ball & mallets activity. For the first time, when I asked students to whiteboard the pattern or rule they’d found, I had multiple groups write out the classic wording of Newton’s 3rd Law. These groups struggled to connect their statement to the lab, but still resisted changing their whiteboard because they knew their statement was true. I think this happened because we don’t have the class culture yet for every student to feel comfortable taking an intellectual risk. Tomorrow, I want to spend some time on the difference between true statements and useful statements to push some of those students away from quoting textbooks.


Physics: Dowels

We’re starting the year with a unit on experimental design and graph interpretation based around a series of labs. For the first one, students are graphing mass vs. volume for some dowels. Things went well overall, but I should have spent a little more time on how to find the volume; I just told them to find it, and a lot of groups weren’t ready to make that leap on their own the first day of school.


Chemistry Essentials: Steel Wool

Students started the mass and change lab from the chemistry Modeling Instruction curriculum. To make the histogram, I had each group write their change on a Post-It, then place it in a physical bin matching their value before I transferred the Post-Its to the whiteboard. The balances were acting up, so most groups saw pretty big changes.

chem histo