# Day 131: Pendulums & Springs & Dam Removal

AP Physics: Pendulums & Springs

Students wrapped up their labs on what affects the period of  springs and pendulums, then whiteboarded the results. I could tell I was rushing the lab more than I have in the past and I ended up taking over a lot of the post-lab discussion and got a bit hand-wavy. As I rush through the last few topics, I haven’t been doing as much with uncertainty, and this is a lab where it would have really helped. I also skipped having students predict the period of a 5 m long pendulum, which made it much tougher to settle on which relationship works best for the length of a pendulum. Going into waves, I need to think about how I will balance the need to keep moving with giving students time to truly engage with the content.

Earth Science: Dam Removal

Students continued work on their dam removal project. Today, they looked at a gradual release, which we modeled by removing one lay of foam at a time. I was very pleased at some of the detailed observations students made and how engaged they were in trying to think about why their observations happened. I’d love to re-work this unit to give students a better grasp of sediment transport in rivers before looking at dams specifically to give them more tools for thinking about the project.

# Day 130: Plickers & Dam Removal

AP Physics: Plickers & Quiz

We continued our routine of Plickers to practice some multiple choice questions, followed by a quiz on this week’s new material. I’m continuing to have students pick an answer individually, then discuss and vote again. There were a couple where students struggled to identify useful representations and, once I gave a nudge, they quickly got to the correct answer. I’m thinking about working in a step where students identify applicable models before they pick an answer to help with that.

Earth Science: Dam Removal

Students used stream tables and a foam model of part of the Salmon River to get some background knowledge for their engineering project. They conducted some observational experiments on sediment transport and deposition, first in a natural, unblocked river, next in a river with a dam, and finally when the dam is removed with a “blow-and-go” approach, where the entire dam structure is removed at once.

# Day 129: Period & River Features

AP Physics: Period

Half the class did experiments to model the period of a pendulum, while the other half did experiments to model the period of a spring. We have three types of springs, and their spring constants are different enough that you can’t test all three with the same mass. Next year, I might have students start by using one spring to test how amplitude and mass affect period, then check their model with a second spring.

Earth Science: River Features

Today, the curriculum called for notes on typical river features, followed by students looking for those features in topographic maps to classify rivers as young or old. Before we did any notes, I had students sort the rivers based on their own categories. They based their categories on things like width or windiness that resulted to very similar sorts to young and old and lead nicely into the vocabulary. When students went back to their groups to sort the rivers by age, I noticed students got less accurate, largely because they interpreted small curves as meanders, making rivers seem older.

# Day 128: SHM Energy & Floods

My classes had a sub while I chaperoned a field trip today, so no photos.

AP Physics: SHM Energy

Students worked on some problems on the role of energy in simple harmonic motion. While there aren’t any circular motion problems today, I’ve been liking the connections we’ve made to circular motion and I’m spending the bus ride thinking about if and how I want to connect today’s work to circular motion.

Earth Science: Floods

Students watched a video and answered some questions on flooding.

# Day 127: Oscillating Particle Model & Problem Scoping

AP Physics: Oscillating Particle Model

Students whiteboarded their video analysis results for the trio of objects in simple harmonic motion. I haven’t done a lot of circular motion in the past, so when we discussed the spinning disk, I was intrigued by how many students were convinced the angle in the video was responsible for the changing velocity. On a whim, I had students sketch the disk from directly above, then had them sketch velocity vectors, including components, at a few points around the disk, which nicely convinced students that they would see similar graphs for the horizontal motion no matter what the viewing angle.

Earth Science: Problem Scoping

This unit includes an engineering project to plan removing a dam from a river. I gave students a memo from their imaginary client and had them do some problem scoping. One of the questions I ask is what background knowledge they will need, which can nicely set up a unit, but students did not identify anything about rivers or erosion as useful knowledge on this project. The memo mentions sediment transport as a major challenge in removing the dam, but I don’t think students saw that as something that would require background knowledge to understand. Even when I handed out the unit’s learning targets, students did not name the target about describing river behavior as one that will be useful. I need to think about how I will address that during the unit.