# Day 124: Mystery Boxes & Metamorphic Rocks

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.

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.

# Day 123: Mistakes Game & Sedimentary Rocks

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.

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.

# Day 122: KVL Diagrams & Igneous Rocks

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.

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.

# Day 121: Kirchoff’s Laws & Rock Cycle

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.

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.

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

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.

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.