Author: Marta R. Stoeckel

Day 87: Assessment & EM Spectrum

/ Marta R. Stoeckel / Leave a comment

AP Physics: Assessment

Students took an assessment over momentum. On the last few assessments, I’ve had a fair number of students use the full class period, when normally I try to keep the weekly assessments closer to half a class period. I need to take a look at my assessments compared to the AP exam to decide if I should shorten the weekly assessments, put a time limit on them so students have to practice pacing themselves, or stick with what I’ve been doing and let them take the time they take.

Physical Science: EM Spectrum

Students worked on a model of part of the EM spectrum, cutting paper to scale to represent the wavelength of some different types of waves. I started this activity when I included more calculations in the course, so it was partly a chance to practice working with scientific notation and switching between wavelength and frequency, but I’ve been taking out a lot of the calculation in the course and the only conceptual ideas this activity gets at is comparing the wavelengths. The standard this activity goes with is about identifying parts of the EM spectrum, so I need to spend some time looking for other activities that can meet the standard better.

spectrum

Day 86: Collisions & Presentations

/ Marta R. Stoeckel / Leave a comment

AP Physics: Collisions

Today, we started expanding the momentum transfer model to cases where two objects are moving before the collision. We got out the photogates so students could find the velocity before and after various collisions of two carts. I got a kick out of how exciting it was for some students to use .

collisions.jpg

Physical Science: Presentations

Students presented their research projects on different energy sources. I like the sort-of-public forum to share their work, but it is tough for students to sit through a bunch of presentations, even though I never spend more than half the class period on them. For next year, I want to put some thought into other formats that might balance the public accountability with more active engagement. Maybe a poster session with some kind of task for students as they view each others’ work.

Day 85: Impulse & Color

/ Marta R. Stoeckel / Leave a comment

AP Physics: Impulse

I introduced impulse today by rolling a cart into a force sensor with a bumper to look at the momentum vs. time and force vs. time graphs. I did this as a demo since we only have one bumper. In my 2nd hour, we got pretty nice data and students easily saw that the area of the force vs. time graph equaled the change in momentum, but my 4th hour got pretty ugly data and I’m not sure why. Afterwards, I borrowed from Michael Lerner again and had students work on solving some impulse problems using SOS diagrams.

bumper

Physical Science: Color

Students wrapped up the lab on color. Using some colored paddle filters, they observed white light bulbs, colored light bulbs, white paper, and colored felt. Next time, I might have them look at the felt under the colored light bulbs, as well, to strengthen their ideas about colored objects under different light sources. After the lab, we confirmed some observations using a diffraction grating on an overhead projector to get colored light. Finally, we revisited the video I’d shown them before the lab to refine and expand their initial explanations. In what is probably old news to people familiar with the role of phenomena in NGSS, the concrete goal of explaining an unexpected observation seemed to help students participate more, as well as give them a firmer grasp on what it looks like to understand the learning target. I’m wondering if using phenomena to frame more labs could help students coming to me from another teacher adapt to my classroom.

filters

Diffraction grating with paddle filters

Day 84: Physics Puzzles & Color

/ Marta R. Stoeckel / Leave a comment

AP Physics: Physics Puzzle

My classes were pretty thin today since the senior social studies classes were watching the inauguration. I gave students who were here the opportunity to do some in-class retakes. I also picked out a couple of fun puzzles from Mad About Physics that students could work on. Students got pretty into the puzzles, especially one where they can get a marble to roll “upwards” by adjusting the space between some straws in a v.

puzzlePhysical Science: Color

Yesterday, a lot of my students were talking about standing waves and longitudinal waves as two separate things, so I started by hooking a spring up to a wave generator to produce some standing waves and show the familiar patterns. Afterwards, I showed them a short video of some demos with a pair of 3D glasses, using it to prompt some questions to motivate a lab on color.

Day 83: Momentum-Time Graphs & Longitudinal Waves

/ Marta R. Stoeckel / Leave a comment

AP Physics: Momentum-Time Graphs

I’m taking a page from Michael Lerner and having my students use momentum vs. time graphs. Today, they worked on translating a p vs. t graph into a v vs. t graph, then do some interpretation. I also asked them about the meaning of the slope on the p vs. t graph, and I was pleased with how many students went immediately to the units to look for hints; in past years, my students needed much more prompting to look there. This year, I’ve been working a lot on getting students to look for meaning in graphs, and its fun to see them taking ownership of those skills.

pt-graph

Physical Science: Longitudinal Waves

Students whiteboarded some problems about longitudinal waves. I steered a lot of questions toward the parallels between longitudinal waves and transverse waves since it is usually a big leap for 9th graders to apply principles we discovered with transverse wave to other types. We also talked about why it might be useful to model something like sound that we know is a longitudinal wave as a transverse wave.

waves

Day 82: Board Meeting & Experimental Error

/ Marta R. Stoeckel / Leave a comment

AP Physics: Board Meeting

Students whiteboarded their results from the cart explosion lab to start building the momentum transfer model. I can tell its been a while since we’ve done a true model-building lab, so students needed some reminders about how to linearize or “translate” y=mx+b, but those skills came back pretty quickly. I did wish I’d had students linearize a bigger variety of graphs so far this year; a lot of students went straight to squaring a variable, so I may want to think about how to get more variety early in the year next year.

When we discussed the lab, a few groups had linerized based on a quadratic relationship and had a fairly large intercept. To decide whether the large intercept made sense, one student suggested exploding the plunger cart off empty space to get a mass ratio of zero and show the velocity ratio must also be zero.

img_20170118_092249

Physical Science: Experimental Error

We spent some time discussing yesterday’s speed of sound lab, focusing on error in measurements. I tried having students stand in different parts of the room based on how they thought frequency affects the speed of sound. When students were picking their spots, there was a lot of great conversation, including some contrasting frequency and speed, which was a great side effect. As we talked about error and what it means for values to be “close”, I had a lot of students ask to move because they changed their mind about what the answer should be.

Day 81: Exploding Carts & Speed of Sound

/ Marta R. Stoeckel / Leave a comment

AP Physics: Exploding Carts

Students worked on the exploding carts lab to build momentum. I rushed through the intro in my 4th hour since they didn’t have a chance to start collecting data, and students struggled with some pieces as a result, especially with what it looks like to graph ratios instead of numbers. I could also tell it’s been a while since we did a true model-building lab; a lot of groups got very focused on specific numbers, rather than the overall pattern. I need to do a better job of making sure we do those kinds of labs regularly.

explosion-1

Physical Science: Speed of Sound

Students used a closed pipe to find the speed of sound. As a result of some of the changes I made this year, students had a much better conceptual understanding of the lab than in the past. The calculation to get the speed didn’t quite seem to fit, though.

While students worked, I conferenced with students about their progress on a project. I met with every student, whether or not they had a draft. I really liked getting a chance to talk to each group; I think it gave a few students a push to stop procrastinating.


Day 80: Exploding Carts & Sound

/ Marta R. Stoeckel / Leave a comment

AP Physics: Exploding Carts

Today’s quiz took longer than I expected. One of my classes had some time to start collecting data on two carts in a mechanical explosion. They are plotting the ratio of the cart masses to the ratio of their speeds after a spring-loaded plunger launches them apart. I thought about using some probeware to measure the velocity, but went low-tech and had them use the ratio of the distances when the carts reached the end simultaneously. I like that this approach encourages students to start looking for patterns as they collect their data.

explosion

Physical Science: Sound

Students used tuning forks and wine glasses to explore some ideas about sound. Students made a lot of great observations and had good discussions with their lab groups and were able to bring some of that back to the whole-class discussion. One of the instructional coaches came by to give some input on helping my students adjust to my approach, and he had a couple of ideas I want to try. Since I keep relationships very qualitative in 9th grade, I ask a lot of questions with limited options, such as whether a variable increases, decreases, or stays the same when another variable changes. The coach suggested I have students physically move to a specific part of the room based on their answer to make it harder to opt out and to facilitate some additional conversations between students. I also like this because it is more obvious to students that we’re doing something different than going over answers like they’re used to. I tend to skip whiteboards in 9th grade, but my conversation with the coach has me thinking they would have some of the same benefits. I need to give some thought to how I can make time for whiteboards in a very tight curriculum.

I also got an idea from grading notebooks this afternoon. I use interactive notebooks, but have gotten very lazy about doing the left side/right side stuff. One of my students has started having a page for each lab, then using the facing page for a summary of the big ideas. That was a good reminder that the left side/right side can actually fit pretty well with what I’m trying to do in the class and I should be having students do those lab summaries.

sound

Day 79: Whiteboarding & Snakey Springs

/ Marta R. Stoeckel / Leave a comment

I spaced out and didn’t take any pictures today.

AP Physics: Whiteboarding

Students worked on whiteboarding elements of the two problems they worked on yesterday. One of the problems involved a block that slides up a ramp and became a projectile; students were either nailing the projectile portion, or completely lost. With an AP test looming, I need to remember to keep spiraling those old concepts back.

Physical Science: Snakey Springs

Students made standing waves and looked for a pattern in how many wavelengths “fit” on the spring. I found a lot of groups missed some of the standing waves, so we made a list as a class of the number of wavelengths they could make a standing wave with and students quickly recognized the pattern.

We also talked a little bit about assessments. After the magnetism quiz yesterday, a lot of students told me they thought it hadn’t gone well, but the most vocal students had perfect scores and the class average was 85%. After talking to students, I think this is related to my challenges engaging students this tri. The earth science assessments they took 1st tri put a lot of emphasis on factual recall, so the reasoning questions I shoot for are big shift for students. I need to think about how I can make it less intimidating to face a new scenario and need to take some time to think on the test.

Day 78: Flying Pig & Quiz

/ Marta R. Stoeckel / Leave a comment

AP Physics: Flying Pig

Today, I got out the flying pig for a lab practical. I had students measure the length of the string and the height of the cone, then use what they know about forces and circular motion to predict the time for the pig to make 10 revolutions.

pig

Physical Science: Quiz

Students took a quiz on magnetism. Afterward, we took a few minutes to review vocabulary for talking about waves that students learned during first trimester. It was pretty teacher directed, but I didn’t want to spend much time on terms students should have mastered earlier this year.