Days 46-50: Force Labs & Impulse

Physics: Force Labs

This week was the force of gravity lab and the spring force lab. Students have been struggling to draw meaning from labs, so I spent more time than usual on “translating” the line of best fit into physics and on the conclusions portion of our lab template for the gravity lab, which seemed to pay off. On the spring force lab, I tasked students with doing that more independently and encouraged students to use their force of gravity lab for reference. I noticed a lot of groups using Fg, rather than Fs, and N/kg as the slope unit, rather than N/cm, which tells me students were focusing on what the right answer was in the force of gravity lab, rather than why it was the right answer. This fits with some other observations I’ve made this year and tells me I need to keep thinking about how to get students focusing on their process in labs, rather than what should be the correct result.

The other physics teacher and I decided to use the spring force lab to introduce force sensors since we have some more involved labs coming up where they will need to use force sensors, and I was really pleased with how quickly students got comfortable with those as a tool. I think it was really valuable for students to have their first exposure one where the measurements were relatively straightforward. I tend to fall into using low-tech tools until there is a good reason to use probeware, but the downside is students are then learning to use the probeware in labs with relatively complex scenarios or when they need to use multiple probes to measure different things. I need to remember the value in starting to use probes in relatively simple labs where we don’t strictly need the probeware.

AP Physics 1: Impulse

This week we introduced momentum and impulse. We started with the Modeling Instruction cart explosion lab where students launch spring-loaded carts off each other and graph the ratio of the cart’s velocities vs. the ratio of the cart’s masses and establish the idea of momentum. Next, we did video analysis of two linked air pucks to introduce center of mass (based on an article in The Physics Teacher by Taylor Kaar, Linda Pollack, Michael Lerner, and Robert Engles). After that, we looked at the change in velocity of carts as they crashed into force sensors with hoop springs to introduce impulse. I’ve tried a few versions of that lab and have yet to have students collect satisfying data, so have been thinking about what I want to try instead. In the course of my thinking, I realized I don’t think I’m satisfied with the storyline of my unit. I like the cart explosion lab to introduce momentum and the center of mass piece to think about what it means to treat an object as a particle, but I think those activities lead more naturally into conservation of momentum than impulse. I think next year I want to try starting the momentum transfer model with the same two activities, but then go straight into conservation of momentum. One route to impulse from there could be asking what if we change the system, such as looking at just one cart at a time in the cart explosion lab to motivate new tools in our model.

Days 15-19: Problems & Technology Tools

AP Physics 1: Problems

A lot of this week was working on calculations for constant acceleration. My students are struggling more with the algebra than in a typical year and it sounds like other teachers are seeing similar things. They are doing some great mathematical thinking, but just aren’t as comfortable as usual with common processes like making a quick graph based on an equation or doing algebraic manipulation. I tend to trust that once students see what math they need to do, I can expect them to get through the math without much support. This year, I need to make sure I’m putting attention to helping students develop their math skills alongside the physics. My course on STEM integration theories last fall got me thinking about how I can go beyond math as a tool in my classroom to instead support meaningful math sensemaking, and this year will be a good push to put what I’ve been thinking about into practice.

I also graded the first lab write-up this week, and my students did much better than I usually see on the first lab write-up. In general, this group of students are stronger than usual at explaining their thinking and the kind of writing I usually look for, which is fantastic in a course like AP Physics 1. I’m really excited to be able to help students build their already strong skills.

Physics: Technology Tools

This week, we wrapped up constant velocity by having students do activities with Vernier Video Analysis and Pivot Interactives. For the video analysis assignment, we had students record a short example of something they thought was constant velocity, then use the video analysis results to test the claim. Since the focus of this activity was on interpreting the position vs. time and velocity vs. time graphs, I think it would have worked well when we were preparing to transition from interpreting diagrams to doing calculations to help break up the stretch we had of paper and pencil problems.

A big goal of these activities was to introduce students to tools we’d been using in a context where students were already pretty solid on the content. When introducing technology, I do a minimal demo and instead provide students with a user guide or other detailed instructions on how to use the tool. I have a lot of students who are more comfortable with a walkthrough, so I spend most of the hour on my feet answering questions by reminding students to use the resources I provided them. These days are tiring, but they pay off with students quickly becoming very independent with these tools as they learn to navigate the user guide or help documents. However, I’ve developed some new back issues in the last year and a half and am very aware today that I can’t currently bounce around the room as much as I used to. We are using video analysis again on Monday, and I need to give some thought to how I will balance ensuring students have the support they need and feel like I’m available for questions with managing my own health.

Distance Learning Week 6

AP Physics 1: Angular Momentum

This is the last topic students need before the AP Physics 1 exam. Students built the model using a Pivot Interactives activity where a marble is fired at a block. One of the questions I asked is whether the distance between the block’s center of mass and the point where the marble strikes has any impact on whether the momentum of the block-marble system is conserved, and I was surprised to see most of my students said yes. I’ve done this activity in the classroom, and I underestimated the importance of the conversations students have on their way to answering the question. I think if I had explicitly prompted students to use tools like an SOS diagram before answering, they would have been more likely to recognize momentum is conserved.

Physics: Pendulum Equation

Students wrapped up the pendulum lab. At the end of last week, I noticed in a discussion board that a lot of students saw their period vs. length graph as linear, so I made a short video talking about how the intercept affects that interpretation. Their first assignment this week was to finish their data analysis and answer a few questions. Most of my students still said their period vs. length graph was linear, which tells me they either didn’t watch the video or didn’t incorporate that information into their work. For my grad class, I’ve been reading about constructivist learning theories in online science courses, and one of the big challenges is most platforms emphasize results and answers, rather than process. Without feedback on their process, students are likely to resist changing a conclusion they’ve arrived at. I need to think about what it looks like to create the space and the expectation for students to share their process in an online environment.

Chemistry Essentials: Balancing

Students have been gradually catching up on old work thanks to the pause I took last week. There’s still a lot of students who aren’t taking visible steps to get caught up, but I’m glad to see some progress.

This week’s assignment was to use PhET’s balancing chemical reactions sim to get an idea of what it means for a reaction to be balanced. I usually start balancing with this activity, and it was really nice to have something that translated so easily to an online environment. Only a few students have completed the assignment so far, but those who have are showing a solid conceptual understanding of what it means for a reaction to be balanced.

Distance Learning Week 5

AP Physics 1: Unbalanced Torque

Students used Pivot Interactives to find a relationship between torque and angular acceleration. The activity has several different bicycle wheels, which lead to some good discussion on the forum as students first compared their results to someone with the same wheel, then compared results to someone with a different wheel.

In both the questions I got about the activity and in the grading I was doing this week, I saw a lot of students struggling with the distinction between different terms related to gravity. That’s been an on-going challenge this year that I think is related to having some students who use a lot of verbal shortcuts. We’ve made a lot of progress on that front this year, and a lot of students were joining me in pushing back whenever someone used imprecise language. I think with out that consistent feedback on language, some students are falling back to old habits. I’m giving feedback on language in students’ written work and sent out a vocab review to all of my students, but am thinking about other options.

Physics: Pendulums

Students used Pivot Interactives to collect data we’ll use to get the equation for the period of a pendulum. This week, we had students collect data, then post their graphs and answers to a few questions to a forum. Next week, they’ll start by linearizing the period vs. length graph. Based on the forum, I’m glad we split the lab up. In the questions, students recognized angle and mass don’t affect the period and correctly explained why the period vs. length graph should have a zero intercept. However, most students described their period vs. length graphs as linear in spite of the large intercepts. Using the discussion and splitting up the lab gave me a chance to catch the issue and record a short video before students started their linearization. It’s been hard to be responsive when I have almost no contact with my students right now, so it felt good to have this opportunity to shift my instruction based on students’ current thinking.

Chemistry Essentials: Pressing Pause

The representing reactions summative was due on Tuesday, and only two of my students had turned in work for the module. Rather than sticking to my plan to start balancing, I pushed everything back so that students have an extra week to catch up before their next assignment is due. I also spread out the remaining work in an effort to reduce the workload. We’re shooting for each class to have around 90 min of work per week, so I’ve been assigning what would take around 30 to 45 min in the classroom each week, but the students I’ve heard from are spending around 3 hours a week on chem. I’ve only gotten work or heard from a few kids since Tuesday, but even if just a few more kids get a credit required for graduation as a result of this week’s adjustments, I’m happy with my decision.

Days 103-106: Kirchoff’s Laws & Energy Card Sort

AP Physics 1: Kirchoff’s Laws

Students worked on developing Kirchoff’s Laws this week. We started with PhET’s circuit construction kit, then got out the power supplies and resistors. Some groups had trouble recognizing the simulation and the physical lab as addressing the same concepts, but explicitly asking groups how their results compared seemed to help students make the connections. There was also some good discussion about why the results in the physical lab didn’t match the simulation exactly. A thermal photo showed some heat at the alligator clips, which lead to some conversation about whether the wires we were using were ideal.

Physics: Energy Transfer Card Sort

This week we worked on starting energy conservation problems. To help the transition from bar charts to problems, I turned some problems Kelly O’Shea and Mark Schober wrote for the New Visions physics curriculum into a card sort. Seeing cards with two versions of the conservation of energy equation seemed to help a lot of students see how to build equations from the bar charts, which made the problems much smoother than in the past.

Days 98-102: Circuits Intro & Energy Bar Charts

AP Physics 1: Circuits Intro

We used PhET’s circuit construction kit to introduce some circuit basics and develop Ohm’s Law. Afterward, we used nichrome wire to test how the length of a wire affects its resistance. The data came out great, with groups that used thinner gauges of wire consistently getting larger slopes than groups who used thicker gauges. I usually skip over resistivity, but, at the AP reading last year, Wayne Mullins shared how he uses resistivity as a conceptual basis for Kirchoff’s Laws and I’m really excited to try that approach with my students this year.

Physics: Energy Bar Charts

This week was all about switching over to energy bar charts. I also noticed students are getting much more vocal during whiteboard sessions. I can’t figure out what’s behind it, but I’m really enjoying it. We’re getting close to the end of the trimester, and a lot of students switch between hours (or even between teachers), so I’m starting to think about how I can help students maintain this progress at the transition.

Day 154: Final Projects, Mistakes Whiteboarding, & Nuclear Structure PhET

AP Physics 1: Final Projects

Students continued to work on their final projects. I have one group that’s interested in finding a way to measure the rate my Van de Graaff generator builds up charge. They spent some time today experimenting with ways to indirectly measure the charge.

Physics: Ray Diagram Mistake Whiteboarding

Students did some mistakes whiteboarding with ray diagrams for curved mirrors. Several students commented on mistakes they thought were especially helpful or interesting, which made me feel really good about the culture I try to build in my class. Students were also sad when they realized this will be their last round of mistakes whiteboarding in high school.

ray mistake.jpg

Chemistry Essentials: PhET Nuclear Structure

Students used PhET’s Build an Atom simulation to experiment with nuclear structure to kick of our nuclear chemistry unit. A lot of the information was a review from the first half of the course, but most needed a refresher.

phet atom.PNG

Day 148: Survey, Curved Mirrors, & Pivot Reaction Types

I was out today, so my classes had a sub.

AP Physics 1: Survey

My district requires all teachers to have students complete a teacher evaluation survey. Since it’s ideal to have students complete it without the teacher in the room, I picked today.  Teachers chose which classes to give the survey to; since AP Physics 1 is the only class where I keep the same students all year, I decided to survey them. While there are certainly flaws in student evaluations, I am interested in seeing the results to get another view of the culture in my classroom.

Physics: Curved Mirrors

Students did a lab to play with curved mirrors to start building some ideas about the images formed by concave and convex mirrors.

Chemistry Essentials: Pivot Interactives Reaction Types

I am as part of Pivot Interactive’s Chemistry Fellows program.

Students used Pivot Interactives to get one more look at some of the different reaction types before their quiz. Along with a single replacement and a double replacement reaction, I had students use what they know about synthesis reactions to finally explain why burning steel wool gets heavier.

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Day 140: Whiteboarding & Pivot Limiting Reactants

AP Physics 1: Board Meeting

Students whiteboarded their results from yesterday to get to a definition of angular momentum, as well as the relationship between torque and angular momentum. They made nice connections to conservation of linear momentum as well as impulse.

Physics: Ray Diagram Mistakes

We did mistakes whiteboarding with yesterday’s ray diagram problems. Students were doing very well figuring out which rays were critical to the problem and catching each other’s mistakes.

physics Ray mistake.jpg

Chemistry Essentials: Pivot Limiting Reactants

I am as part of Pivot Interactive’s Chemistry Fellows program.

Students used Pivot Interactives to do a lab involving limiting reactants. Since lab data makes it tough to use particle diagrams, I tried having students convert their balanced reaction equation into “for every” statements. A lot of them were pretty successful using those statements to make sense of the other calculations I asked for.
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Day 139: Angular Momentum, Ray Diagrams, & Limiting Reactants

AP Physics 1: Angular Momentum

I am as part of Pivot Interactive’s Chemistry Fellows program.

Students used Pivot Interactives to explore collisions that involve angular momentum. I especially like the activity they have with a marble fired at a wood block since it provides an opportunity to review linear momentum, as well as discover a relationship between torque and angular momentum.

Pivot rot collision.PNG

Physics: Ray Diagrams

Students sketched ray diagrams to explain their observations in Friday’s lab. Students were able to make good connections between their ray diagrams and their observations.

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Chemistry Essentials: Limiting Reactants

Students whiteboarded some limiting reactant problems, emphasizing the particle diagrams that could be used to solve the problems.

chem limiting (2).jpg