# Days 15-19: Building a Force Model

This week was all about starting to build a model of forces. We started by tapping bowling balls with mallets, using a version of the activity based on Frank Noschese’s. Students were quicker than usual to recognize that they had to juts leave the bowling ball alone once it was moving to keep it moving at a constant speed, but I still pulled up an old image I made with motion shot to get some additional evidence. After that, we moved into a version of interaction stations from Kelly O’Shea where students identified forces based on stretch, compression, and shear. Finally, we wrapped up the week with some mistakes whiteboarding with force diagrams. When I introduced system schema and free-body diagrams, I didn’t emphasize enough that the free-body diagram only needs to show forces that cross the system boundary, but that lead to some great conversations during the whiteboarding as students figured out what they needed to include. One student commented that almost all of their mistakes related to including more than they needed to, which lead to some nice discussion about the fact that the hardest part of physics is often figuring out what is relevant.

# Day 36-40: Newton’s Laws & Whiteboarding

AP Physics 1: Newton’s 2nd Law

Students used a modified half-atwoods to find a relationship between force and acceleration. The quality of the results varied a lot. I’ve been talking to the AP Chemistry teacher, and we think part of what’s going on is students aren’t often asked to use their data in meaningful ways before they get to physics, so it doesn’t make sense to take the time and attention to collect data carefully. I need to put some thought into how to help students place value on good data collection and build the skills required to collect good data.

After developing Newton’s 2nd Law, we spent some time combining the new equation with vector addition diagrams. Students are starting to buy in to the diagrams as useful thinking tools, which is always a lot of fun to see.

Physics: Free-Body Diagrams

Students have been working on Newton’s 1st Law and drawing free-body diagrams. We have some problems that often lead to great discussion with mistakes whiteboarding, but I’ve been struggling to get students in one of my hours to speak up during whole-class discussions. To help with that, I tried doing a short gallery walk prior to any of the whiteboard presentations this week. Once the whiteboards were ready, I had students visit each board with their group and make notes on their worksheet about potential mistakes they saw or questions they had. During the whole-class discussion, there was a lot less silence and we heard from some students who don’t often speak up, which was exactly what I was hoping for. I think it also helped that I shared those goals with students before we started. When a student joked those goals aren’t going to happen, I assured her I’m very stubborn and am convinced the class can get there.

# Days 32-35: Newton’s 3rd Law & Newton’s 1st Law

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.

# Days 20-23: Newton’s 1st LAw & Constant Acceleration Model Building

This week was a little goofy. Students were off Friday for a staff development day and it was homecoming week, so classes were shortened on Monday and Thursday for festivities.

AP Physics 1: Free-Body Diagrams

This week was all about Newton’s 1st law. We started with the bowling ball lab to come up with a formulation of N1L, then worked on representing forces with free-body diagrams and system schema. Both sections had mistakes whiteboarding sessions that were overall really good. There was a debate about whether a projectile should experience air resistance that had a lot of good thinking. We ended up grabbing a softball out of the storeroom and capturing an image of it rolling in Motion Shot to see if it had a constant velocity. There was a much more intense debate about air resistance than I’ve seen before and I think the group presenting felt like it became a “gotcha” moment. I need to think about how I could have intervened differently in that discussion to shift the tone it took on.

Physics: Constant Acceleration Model Building

Students used video analysis to produce graphs of the motion for an object on a ramp. I was ornery about making students attempt to follow a reference guide I made before I’d help with the technology, which made it a lot easier for me to spend time with students who needed help troubleshooting. The results were better than when I’ve used photogates, but still fairly messy. I think part of the problem is, regardless of the approach, students rush on key pieces and get sloppy data as a result. I need to think about how to slow my students down at key steps. It was also tough to get students to speak up during the board meeting, even with doing a gallery walk and jotting down some observations with their group beforehand. I’ve got more students than usual who underestimate how much they know and are wary of jumping in as a result. I have some work to do on increasing the social safety in my classroom and helping students recognize their contributions.

Students also did Kelly O’Shea’s CAPM card sort. Interestingly, even though this fell on the day of our homecoming pep fest, students were overall very engaged in the activity. I saw a lot of the same students I struggled to get to speak up during the board meeting asking great questions and sharing ideas during the card sort. I think the small group setting was a factor. I need to give some thought to what else made students comfortable speaking up so much in their small groups and how I can bring that to whole class discussions.

# Day 26: Problems, Bowling Balls, & Assessment

AP Physics 1: Problems

Students worked on a mix of problems on impulse and on using formulas for types of forces. During the second part of class, students whiteboarded problems for a gallery walk.

Physics: Bowling Balls

Today was bowling ball day! Students worked through Frank Noschese’s bowling ball and mallet activity.  After getting a class rule so far for taps and bowling ball motion, a few students commented it reminded them a lot of Newton’s 1st Law from 9th grade physical science. Imagine that!

Chemistry Essentials: Assessment

Students took their gas laws quiz today. Last year, I was pretty good about planning some kind of activity for after the assessment. About half my students take the assessments in a pull-out setting and many of them need more time than the students who stay in the classroom, so I did a lot of nature of science-type activities with students in the classroom while pull out students finished their assessments. I’ve been dropping the ball on that and need to get back into that routine. The students who stayed in the classroom weren’t getting into trouble when they finished, but I’d prefer to have something worthwhile for them to do.

# Day 8: Bowling Balls, Motion Maps, & Density

AP Physics 1: Bowling Balls

Students worked on a bowling ball and mallet lab based on Frank Noschese’s version. There was some good debate about whether a bowling ball needs to be tapped to roll at a constant speed, so we used the Motion Shot app to make a motion map we could use to check.

Physics: Motion Maps

To introduce motion maps, I drove a fridge rover across my whiteboard and marked the position at regular time intervals. Motion maps also linked nicely back to the buggy lab, since I forced students to use time as the independent variable. Students then worked on problems; in my 1st hour, most of my students chose to work at desks mostly independently, which I think made the problems more challenging for both my students and for me. In my 6th hour, I started by letting students know the problems were designed to be done in groups and talked about the advantages of completing the task in a group. I’m also wondering if it would help if I made more use of a strategy I got from Designing Groupwork: Strategies for Heterogeneous Classrooms where we take time for some explicit class discussions about what skills are needed for a task to emphasize the value of multiple abilities.

Chemistry Essentials: Density of Water

Students did a lab to find the density of water, then we had a short board meeting with the results. We kept the board meeting pretty simple and I was very pleased with how it went; my favorite observation is a student who noticed that different groups had data points at different masses, but every group still got the same slope.

# Day 48: Unbalanced Forces, Quantitative Interactions, & Bohr Model

AP Physics: Unbalanced Force Problems

Students started some problems on unbalanced forces. I started by having a group demonstrate their success on last week’s lab practical, then asked students what should happen if we swapped out a lighter marble. Once we tried it, we used vector addition diagrams to find the acceleration of each marble and show the mass doesn’t matter.

Physics: Quantitative Interactions

I borrowed an idea from Kelly O’Shea (I think she’s planning a blog post) and, instead of doing balanced force problems on a worksheet or out of the textbook, I gave students 5 different stations to work through. Several groups went back to their force of gravity lab to figure out the first station, which was great for reinforcing that the labs and problems are connected. The downside is I used a mass today that many used on their lab, so they were able to just read off their data table.

Chemistry Essentials: Bohr Model

Students used PhET’s Build an Atom simulation to play with the Bohr model. The activity took a little longer than I thought, so no one was able to finish, but students were having some good questions about the changes as they added pieces to their atoms and how that fit with patterns on the periodic table. At the end of the hour, I got out the gas tubes and diffraction gratings so students could see some of the evidence for the Bohr Model. They had a lot of questions we didn’t have time to answer, but I’m hoping that will make for a good way to start class tomorrow. I’ve been trying to put something engaging and thought-provoking at the end of the hour to combat students trying to line up at the door or slip out of the classroom in a positive way, and its had the side effect of making it easier to start class the next day since students show up with questions they are excited about answering.

# Day 39: Ramp Whiteboards, FBDs, & Electrolysis

AP Physics: Ramp Whiteboards

Since a recent quiz used a free-response problem from the AP Physics exam, I gave students part of the hour to use the scoring guide to review their work. Students seemed to like seeing the level of detail the College Board is after.

Afterward, students prepared whiteboards for the ramp lab we’ve been working on. I made some changes to my approach and can tell I need to do a little more work on helping students interpret the graphs and data tables from the photogates. Overall, results are looking pretty good.

Physics: Free-Body Diagrams

We discussed some of the interaction stations to get to the point of defining a few key types of forces. Afterward, I introduced them to interaction diagrams and free-body diagrams using the hover puck in an activity adapted from Kelly O’Shea. For the puck traveling at a constant velocity, one of my hours had some really good small group discussion about whether there is a forward force on the puck, though neither class got to a whole group discussion today.

Chemistry Essentials: Electrolysis

We did a gallery walk to go over yesterday’s problems. I also showed students an electrolysis apparatus to have some conversation about how we know water is two hydrogens and an oxygen.

# Day 38: Ramps, Interaction Stations, & Pure Substances

AP Physics: Ramps

Students worked on collecting position vs. time and velocity vs. time data for a cart on a ramp. Based on the questions I was getting during the lab, a lot of groups would have benefited from more discussion about what the photogates were measuring and how that translated into the graph and data table on the LabQuest. I should talk to our tech guy about installing the LabQuest emulator to help facilitate those conversations.

Physics: Interaction Stations

To keep building up the idea of forces, students worked through a series of interaction stations Brian Frank wrote about using a worksheet from Kelly O’Shea. Students got tripped up identifying where the interaction was taking place, mostly because they were overthinking it. Some were bothered that they could see more than one interaction, but only needed to talk about one on their worksheet. Next time, I might make it more open to encourage students to discuss multiple interactions.

Chemistry Essentials: Pure Substances

Students worked on a Modeling Instruction worksheet differentiating between pure substances, mixtures, compounds, and elements. I like pure substance, mixture, and compound were all motivated by the labs with iron and sulfur, but students had trouble connecting the idea of an element. We haven’t done hydrolysis yet, and I wonder if that might have helped motivate elements.

# Day 37: Dueling Buggies, Dueling Fan Carts, & Chemical Change

AP Physics: Dueling Buggies

Students wrapped up the dueling buggies lab practical with very satisfying results. Usually, most of my students look for the intersection of the position vs. time graphs, but this year I had a lot of groups decide to solve the system of equations. I think that is just an artifact of doing the lab later than usual, when students are in the routine of connecting math and physics, and of moving pretty quickly through the CVPM worksheets.

Physics: Dueling Fan Carts

We talked about the rules students had for tapping and motion after yesterday’s bowling ball lab, then moved into a version Frank Noschese’s dueling fan carts. Frank’s activity calls for high vs. off, but I added in off vs. high as a separate scenario to help with the idea of directionality. This is the first time I had groups revise their rule after the fan carts, and I was really pleased with how that went. I think that approach also helped cement the connections between the bowling ball lab and the fan carts, and the connections are something I’ve seen missing so far.

Chemistry Essentials: Chemical Change

Students heated yesterday’s mixture of iron and sulfur to see if the properties changed. Just about everyone was very excited about using fire, but it was tough to keep them focused on making and interpreting their observations. Since I only had a few questions, I projected them, rather than making a handout, but something about a handout seems to give my students more sense of individual accountability. I think the handout serves as a physical reminder of the questions they need to answer, so I will try to stick with making handouts.