Author: Marta R. Stoeckel

Day 127: Oscillating Particle Model & Problem Scoping

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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.

shm trio

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.

Day 126: SHM Trio & Water

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AP Physics: SHM Trio

Students downloaded a Direct Measurement Video of three objects in simple harmonic motion and did some video analysis. There was lots of great discussion about why the pendulum’s y-position vs. time graph showed a different period than the x-position vs. time graph. I also really liked the conversations students had about whether the net force on each object is constant. My favorite moment was when a student called me over for help, and the person sitting next to her said “You need to think about it first!” The second student then started asking questions to help the first student figure out the answer she needed. Yay, students!

SHM Trio

Earth Science: Where is Earth’s Water?

Students filled beakers with their prediction for how Earth’s water is distributed, then got the actual distribution and compared. I liked how doing their own prediction first made it much more dramatic when they got the actual results, and saw just how little of Earth’s water is in a form we can really use.

water.jpg

Day 125: Plickers & Earth Resources

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AP Physics: Plickers & Quiz

Between now and the AP exam, my plan is to spend Fridays on multiple choice practice, followed by a quiz. We used Plickers again, with students first voting on answers individually, then talking to a peer before voting again; its really interesting to see how their answers shift with this process. I picked several problems where thinking in terms of a system’s center of mass is useful, and students seemed to grasp that idea, though we will need to revisit to make sure it is solid. There were a lot of great conversations along the way.

plicker

Earth Science: Earth’s Resources

I ended up doing some pretty traditional notes to address the learning targets on Earth’s resources. I’d love to put together an activity where students have to argue whether a certain mine or pollution source is worth it (come to think of it, the proposed PolyMet mine near the BWCA would have made for a great Socratic seminar or philosophical chairs), but I ran out of time to prepare something for this year. My students didn’t mind the notes; it turns out several of them had a test next hour in AP Human Geography over a lot of the same material.

Day 124: Mystery Boxes & Metamorphic Rocks

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AP Physics: Mystery Boxes

Today, students worked through an activity I got from The Physics Teacher. Groups were given a black box with three light bulbs and had to figure out how the bulbs were wired without opening the boxes. I front-loaded some thinking by having students sketch the four possible circuits and do some KVL diagrams and arrows to show currents, which students were then very successful at applying to interpret the behavior of their boxes. The main issue I ran into is many students students initially wanted to treat equivalent circuits with slightly different arrangements as different circuits. For example, groups often drew one parallel circuit with one bulb on the first branch and two on the second, then a second parallel circuit with two bulbs on the first branch and one on the second. The KVL diagrams provided a nice tool for showing why those circuits are equivalent.

mystery

Thanks, Lotze, for drilling holes in all the boxes!

Earth Science: Metamorphic Rocks

Students identified metamorphic rocks today. Similar to the igneous rock lab earlier this week, I started by having students sort the rocks based on visible properties. Most groups went with whether the rocks were layered, which lead nicely into foliation. A few groups when with sheen, which is the other major property used to identify rocks on this key. Students struggled to tell the difference between marble and quartzite using the key. After the lab, I talked a little about hardness and the acid test, but it would be nice to give students some tools they can use during the lab to differentiate those two.

met rocks

Day 123: Mistakes Game & Sedimentary Rocks

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AP Physics: Mistakes Game

Students played the Mistakes Game with some electric circuit problems. I noticed students who drew arrows to represent the possible current paths tended to be much more successful, so in my 4th hour I explicitly made that part of the instructions. I also took a few minutes in that hour to give students a series and a parallel circuit to have students rank the resistances to solidify that idea. I think I will start with that in 2nd hour tomorrow.

wb

Earth Science: Sedimentary Rocks

Student worked on identifying sedimentary rocks using a key. There were some good discussions in lab groups about the fuzzy boundaries between some of the rock types. I struggled a bit with what thinking students could do to go beyond just using the identification key. I think I’m going to run into the same issue tomorrow with the metamorphic rock lab.

sed rocks

Day 122: KVL Diagrams & Igneous Rocks

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AP Physics: KVL Diagrams

I introduced students to Trevor Register’s KVL diagrams and had students start working some problems. I also have students trace the possible current paths on the circuit diagram to give students a visual for Kirchoff’s Current Law. We also had a quiz today, so most groups only got through the problems that were purely series or purely parallel, but there was a lot of great conversation with students pushing each other to be specific in their use of vocabulary.

kvl

Earth Science: Igneous Rocks

Students worked on identifying different types of igneous rocks. The identification key starts with texture and uses some technical terms for the textures, so before students got the key, I had them group their samples by similar texture. This seemed to help students make sense of terms like “grained” and “frothy” as they apply to rocks. It felt a bit disconnected from the work we’ve done on the rock cycle, which feels disconnected from what we did on Earth’s layers, so I’d like to work on a clearer storyline for this unit.

ig rocks

Day 121: Kirchoff’s Laws & Rock Cycle

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AP Physics: Kirchoff’s Laws

Students attempted to apply their patterns to some fill-in-the-blank circuits and whiteboarded statements to describe the patterns they’d found using both the simulation and the real-world lab. It definitely felt more challenging than last year, but I think it was because of how I broke things down to get into a computer lab. Next year, I will get laptops or tablets instead so we can stay in the classroom, then do both the simulation and physical lab for series one day, then do both versions of the parallel lab the next day. That should reduce how much information students are trying to keep track of to make this series of labs more manageable.kvl wb.jpg

Earth Science: Rock Cycle

I modified an activity from the middle school Modeling Instruction curriculum using crayons to look at the rock cycle. I had students make some shavings to represent weathering and erosion, then squish the shavings together for a sedimentary rock. Students then melted their sedimentary rock and let it cool to make an igneous one. Next time, I think I’ll have them use higher pressure, maybe from a stack of books, to get metamorphic rocks in there.

crayon

Day 120: Kirchoff’s Laws & Rock vs. Minerals

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AP Physics: Kirchoff’s Laws & Plickers

I split the class period today into two halves. In the first half, we got out resistors and power supplies to do the real-world version of the Kirchoff’s Laws lab students did on Wednesday. My directions were to see if the patterns they’d found Wednesday worked with today’s materials. I used the same slide as last year, but students had a much harder time figuring out what to do this year. I think the problem is we spent yesterday whiteboarding a different lab, while last year I kept the simulation and real-world versions of Kirchoff’s Rules back-to-back. Next year, I think I will take advantage of my department’s iPads and the HTML5 version of the sim to do it in my classroom. Then I can split up the labs by series and parallel, rather than by simulation and real-world and working around when I can get a computer lab.

The other half of the class, we used Plickers to revisit some multiple choice problems from last tri’s final exam. One problem asked why the speed of a projectile does not change at the highest point. After talking to some other teachers, I really like thinking about that one from an energy perspective, using the idea that a force perpendicular to the motion will not change the energy. To drive that home, I used a mallet to get a bowling ball going in a circle so we could talk about whether the force from the mallet changed the bowling ball’s energy.

plicker

Earth Science: Rocks vs. Minerals

Students used their work from yesterday to identify some of the key differences between rocks and minerals. Since the book of stereograms students used yesterday also had a gem section, I included those in our discussion. Students pretty quickly recognized they had trouble identifying characteristics distinguished minerals and gemstones, which lead nicely into the idea that gems are just particularly valuable minerals.

category

Day 119: Whiteboarding & Mineral Intro

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AP Physics: Whiteboarding

Students whiteboarded their results for the Ohm’s Law lab and an electric potential difference activity I had them try in yesterday’s sim. Students plotted voltage vs. resistor with the multimeter’s ground probe in several different positions to see the change is always the same. The analogy between gravitational potential and electric potential doesn’t seem as clear for my students as in the past, so next year I might go back to having students map electric potential.epd

Earth Science: Mineral Stereograms

I did a few notes on what caused the early Earth to melt and form layers. Afterward, students spent some time with books of stereograms of rocks, minerals, and gemstones. I wrote some questions to get students thinking about the key characteristics of each category and it was fun to listen to some of the things students were noticing.

stereo

Day 118: Circuit Sim Again & Earth’s Layers

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AP Physics: Circuit Sim Again

Students used PhET’s circuit construction kit to explore Kirchoff’s Laws in series and parallel circuits. I also tried to mimic an extension of an electric field mapping lab by having students place the ground probe of the voltmeter at different points in the circuit, then move the measuring probe around the circuit. I liked that this got students noticing that the total change in voltage is always the same and it got them thinking about what a negative voltage means. On the Kirchoff’s Laws portion of the activity, I saw a lot more variation in how students thought about the patterns than in the past, which was a lot of fun. I was especially impressed when one student pretty much derived the equivalent resistance for a parallel circuit.

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Earth Science: Earth’s Layers

Today, we built on the scale diagrams students made yesterday, adding some information on the properties of each layer. I tried to get some deeper thinking by asking questions like how two layers could have similar composition, but different densities, and it was a little tougher than I expected. I think if I’d primed students with some questions about pressure, that task may have been easier. It bothered me to just state give students information about the interior of the Earth, so I spent a few minutes talking about seismic tomography with my students. Next time I teach the course, I’d love to come up with a lesson to give students an analogous experience.