Days 142-146: Projectile Video Analysis & Angular Momentum

Physics: Projectile Video Analysis

Students used Vernier Video Analysis to get velocity vs. time and position vs. time graphs for a projectile. I saw some students including their throw or after the projectile landed in their video analysis, which makes sense since I’ve seen students struggling more than in the past with recognizing what is the most relevant part of an object’s motion. I think that probably could have been addressed with spending a little more time on some pre-lab discussion. It was a lot of fun to hear their small-group discussions making sense of the graphs once I had them draw a free-body diagram and they recognized why the graphs looked the way they did.

AP Physics 1: Angular Momentum
We wrapped up unbalanced torque and rushed through angular momentum. Students started an activity in Pivot Interactives, but were moving through it more slowly than I’d hoped, so I ended up doing a lecture on angular momentum. It’s not my preferred approach, but the clock is ticking for AP exam day! Students seemed to get the concept during the lecture. I did a lot of emphasizing the parallels to linear momentum, which seemed to help. We’ll be doing some problems and whiteboarding next week to wrap up angular momentum, which will be a good opportunity for me to check how clear their understanding is.

Days 138-141: Popper Hoppers & Unbalanced Torque

We had Friday off this week. I think staff and students alike were very happy to have a long weekend.

Physics: Popper Hoppers

This week we wrapped up energy. After finishing the bouncy ball evidence-based reasoning from last week, we got out the popper hoppers to use energy to find the spring constant of the toy. We haven’t done as much having students decide what measurements to take as I’d like, so students struggled a little at first with what measurements to take. I showed them a strategy from one of my past AP students wo would write out the equation she was going to use to solve for the target variable, then put check marks next to each of the other variables once she had a step in her procedure that would get her a value for that variable. That was exactly what students needed to get a solid plan for the practical.

AP Physics 1: Unbalanced Torque

This week, we worked on unbalanced torque. We used another Pivot Interactives activity (Disclaimer: I work for Pivot Interactives as a content writer. This activity should be published soon!) since I haven’t had a chance to play with the hands-on equipment we purchased for rotation in fall 2019. I’m trying to be pretty conscious of making explicit connections to unbalanced linear forces, both to make sure students aren’t starting from scratch in their understanding and to embed review of earlier topics. Students are seeing those connections pretty clearly, which is great to see.

I also started a countdown to the AP Physics exam on my whiteboard, and noticed students are more focused when working problems. I think the countdown is adding some sense of urgency to what we are working on.

Days 133-137: Bouncy Balls & Torque

This week was a little odd since we didn’t have any classes on Tuesday to accommodate state testing. The juniors took the ACT, but the seniors had an asynchronous day. A lot of the seniors really appreciated having a day to follow their own schedule and relax a bit.

Physics: Bouncy Balls

We started an evidence-based reasoning activity to determine what interaction dissipates a bouncy ball’s energy (you can find more details in my article from The Science Teacher). This week we focused on preparing for doing the video analysis by sketching energy bar charts, force diagrams, and motion graphs for if air resistance is responsible for most of the dissipated energy and for if the impact with the table is responsible for most of the dissipated energy. We then used those diagrams to get to some testable predictions about things we can measure with video analysis that will distinguish between those two explanations. Students found this process challenging, but I was really pleased by how they connected other ideas from this course to energy.

AP Physics: Torque

To introduce torque, students set up some meter sticks as levers and looked for a relationship between the force exerted by a hanging mass on the meter stick and the force required to balance the meter stick. After we discussed that lab and took some notes on torque, I showed students a second class lever and asked them to determine if that type of lever showed the same relationship as the first class lever we started with. While I don’t discuss the classes of levers with students, I like that this activity helps emphasize it is the direction of the torque, rather than the direction of the force that is important. This activity was tougher for my students than I expected, I think because I rushed the post-lab discussion after the first class lever, so they weren’t as clear as they needed to be about the relationship we’d found the first day.

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.

Distance Learning Week 4

Based on how we’re being encouraged to approach distance learning, I’ve been posting at least one full week of material for students at once. This week, the mental switching it takes to grade last week’s work, answer questions about this week’s work, and plan next week’s work, especially with three different courses, started to get to me. I’m working on planning out my work tasks better so that I’m not switching gears quite as often.

Thursday and Friday were especially tough this week. Governor Walz announced on Thursday that schools will be continuing distance learning through the end of the school year. While it is absolutely the right call and we’ve been expecting it for a while, it was tough for staff and students to hear for sure that we won’t be back together this year.

AP Physics 1: Balanced Torques

Students used PhET’s Balancing Act simulation to develop rules that lead into balanced torque. Based on the discussion board, students were pretty successful at getting the ideas I wanted them to get. They also seemed to have a lot of success applying their rules to the problems.

I also saw signs of some fatigue setting in among my students. Some kids were missing written information I think they would normally catch and many are quicker to get frustrated than I’m used to. Based on a survey I gave my students to see about how many hours per week they are spending on school, it is no wonder they are getting worn out. While students consistently said my class has a relatively light workload, I need to do what I can to keep it light and even reduce it. It’s hard when I still have content to cover and the AP exam is close, but my students’ well-being is more important than a test score.

Physics: Pendulum Representations

Students did some video analysis of a pendulum to start thinking about motion graphs and other representations, including free-body diagrams and energy bar charts, for simple harmonic motion. Students struggled to make some of the connections I usually ask for, which I think is a result of most kids working independently rather than having the opportunity to talk things over with each other.

I’m seeing fewer signs of strain from my physics students. Most are putting in 1-2 hours per week on Physics, which they consider reasonable. I’m also hearing from students that they really appreciate having deadlines every few days, rather than having everything due on Friday as a lot of classes are doing, since it helps them spread out their work.

Chemistry Essentials: Representing Reactions

This week, we continued working on translating between words, formulas, and particle diagrams for complete chemical reactions. The students I’ve talked to are making good connections with what they learned in the formula writing module and mostly need confidence and reassurance rather than significant help with the content.

This is the class where I’m feeling the absence of face-to-face instruction the most. About half of my students haven’t done anything on the Schoology site or responded to my emails or phone calls, which is tough to see. I had a conversation with the para who supports the course this week, and we see two major challenges. First, we see a lot of students who get off-task when they are confused or stuck. In the face-to-face classroom, we can not only redirect them, but sit down with the student to work through their questions. Based on what we’ve heard from a few parents, we think some students are getting stuck in this avoidance. Second, I find I have to earn the trust of students in this course before they are comfortable asking me questions, but it’s been tough to earn that trust when we’ve never met. I’ve had some success texting with kids since it is a very low-stakes interaction, but teaching chemistry by text message is hard. The good news is the para has good relationships with many of the kids struggling and is very comfortable with the curriculum for this class, so she’s been able to step in with some kids too nervous to ask me questions.

Day 142: Assessment, Reflection Lab, & Backwards Problem

AP Physics 1: Assessment

Students took their quiz over angular momentum, and we have now officially finished content. Wooo! 2 class days to spare!

Physics: Reflection Lab

We got out the geo mirrors and some plane mirrors to start exploring reflection. I like to start each optics topic with a lab making qualitative observations. The instructions I gave students today need some work; students had trouble parsing the wording to make meaningful observations.


Chemistry Essentials: Backwards Problem

As a quick warm-up before taking the limiting reactants quiz, I had students whiteboard what I called a backwards problem. I gave them a reaction and told them what should be the limiting reactant, then had them sketch a particle diagram for a situation showing starting conditions that would lead to the right limiting reactant.

A few kids were feeling stressed out about this quiz, so we also took a few minutes to revisit the reassessment policy, including the fact that I’m putting retakes into our normal assessment process, which helped lower the stakes and let students feel a little calmer about the quiz.

chem backwards prob.jpg

Day 141: Free Response, Quiz, & Limiting Reactants Lab

AP Physics 1: Free Response

We worked a few released free response problems related to angular momentum. I also set up a couple of angular momentum demos, including a spinning Hoberman sphere. Students seem to be grasping the big ideas, which is good since we only have a few more class days before the AP exam!


Physics: Quiz

Students compelted a groupwork reflection, then took their quiz on ray diagrams for shadows and pinholes. I’ve only glanced at their work, but I’m pleased with how the quizzes look.

Chemistry Essentials: Limiting Reactants Lab

Students did a reaction with copper chloride hydrate and aluminum. I had different groups use different quantities so that the limiting reactant varied by group; students were really intrigued by the stark differences in some of the finished reactions. Students did very well using “for every” statements to do stoichiometry when the particle diagrams don’t work. I am glad I introduced the statements yesterday with Pivot; I think starting that skill without having to worry about good lab technique helped it sink in better.

chem limiting (3).jpg

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.
pivot limiting.PNG

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.

physics ray (1).jpg

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