Author: Marta R. Stoeckel

Day 89: Cost Effectiveness of Light Bulbs & Vocab Intro

/ Marta R. Stoeckel / Leave a comment

Physics: Cost Effectiveness of Light Bulbs

After a brief introduction to electric power, I tasked students with figuring out which of several light bulbs is the most cost effective. I provided them with the cost and estimated lifetime for each bulb and the current rate the local electric company is charging, along with some Kill-A-Watts they could use to take some measurements.

Calculated costs to run for 15,000 hours
Calculated costs per day

Chemistry: Reversible Reactions

After a quiz on limiting reactants, students used the textbook to start defining reversible reaction and equilibrium.

Day 88: Ohm’s Law & Limiting Reactants

/ Marta R. Stoeckel / Leave a comment

Physics: Ohm’s Law

Students wrapped up using the PhET circuit construction kit to develop Ohm’s Law. Students were able to pretty easily reason out the formula based on their graphs. Looking back, I wish I’d had students put their experimental conditions and equations on the boards, as well. I usually try to keep the boards pretty simple since I have some big classes, but I think that information would have added a lot of value to the conversation in this case.

IMG_1610

Chemistry: Limiting Reactant Practice

Today, students did some limiting reactant problems where the given and desired information is in grams, rather than moles. I was really pleased at how easily most of them worked through the problems. A lot of my students were struggling to connect ideas between different days earlier in the trimester, so it was great to see how many readily pulled out earlier skills and problem solving strategies to help today. I also saw a big jump in the quality of the questions I’m getting from my students; one student in particular was really focusing on the why when she was talking to me, when in the past she seemed most interested in getting something to write down. I’ve been having a lot of conversations with this class about how learning works and sharing why I do things the way I do, and I’m hoping I can get students to continue with the things I saw today.

Day 87: Ohm’s Law & Limiting Reactants

/ Marta R. Stoeckel / Leave a comment

Physics: Ohm’s Law

Students used PhET’s circuit construction kit to do a short activity based on the PUM materials to help orient them to the sim, then started looking for a relationship between current and potential difference. I loved it when, during the orientation activity, several groups got curious about the mysterious resistors in the kit, and immediately tried adding them to a circuit to see what they do, without any prompting or intervention on my part. There was also some great discussion and debate in one class about what exactly the blue dots represent. There were also many attempts to electrocute the dog.

dog circuit

Chemistry: Limiting Reactants

After a short percent yield quiz, we had some class discussion to formalize what students found in yesterday’s PhET sim on limiting reactants. I picked some reactant quantities for one of the reactions in the simulation, then had students get into groups and try to predict what they would produce and what the leftovers would be. Before students went to their groups, we had some conversation about what I was looking for. I tried to emphasize that I wasn’t after right answers; instead, I wanted them to share different approaches so we could decide on some useful ways to think about this kind of problem. There was a nice mix of students who focused on the equation given for the reaction and students who sketched diagrams.

IMG_1609

Day 86: Intro to Circuits & Limiting Reactants

/ Marta R. Stoeckel / Leave a comment

Physics: Intro to Circuits

I gave each group a bag with a mix of various items and asked them to use those items to try and light up an LED. In the past, I’ve told students their task is to light up the bulb, but they should keep track of what doesn’t work. This year, I was more conscious of stating the goal was simply to document what does and does not work so we could look for patterns, and I was much happier with how the exploration went. This was also the first time I used LEDs for this lab, instead of miniature incandescent light bulbs, and I liked the opportunity to reinforce that current has a direction. As an added bonus, the LEDs I have required two AA batteries, which gave the students more options to try. We wrapped up by watching a short excerpt from from the Private Universe series of MIT and Harvard grads trying a similar task.

IMG_1608

Chemistry: Limiting Reactants

Students worked through PhET’s Reactants, Products, and Leftovers simulation to introduce the idea of limiting reactants. I found a lot of students were looking for confirmation that their answers were right, even when the simulation showed the answer. When I talk to many of them, it sounds like they’ve gotten into the habit of assuming they are wrong in school. I need to continue to work on building a culture where my students feel like their ideas have value and to work on strategies to help students analyze their answers, right or wrong.

IMG_1607

Day 85: Whiteboarding & Percent Yield

/ Marta R. Stoeckel / Leave a comment

Physics: Whiteboarding

Students whiteboarded their answers to Friday’s questions. There were a few questions where students had some good discussion and connected some questions back to the lab where they’d mapped electric potential. I still need to work on getting students to talk to each other more than they talk to me.

IMG_1606

Chemistry: Percent Yield

Students worked on some problems calculating percent yield. While they can do the calculations pretty easily, the concept seems pretty abstract to them. I need to find a good lab to make percent yield more concrete.

Day 84: Electric Potential & Whiteboarding

/ Marta R. Stoeckel / Leave a comment

Physics: Electric Potential vs. Gravitational Potential

Students worked on a worksheet from the Modeling Instruction curriculum that draws analogies between gravitational potential and electric potential. Several students commented that relating electric potential to something more tangible helped them make sense of what we’ve been doing. I also had a very good conversation with a student about how last trimester, she really liked how connected the mechanics topics were, but doesn’t have the same sense with electricity. This confirms that I need to keep working on my storyline for this trimester, but it was great to hear some of the metacognition the student was doing and I consider it a sign of a good class climate that a student was willing to have that conversation.

Chemistry: More Whiteboarding

Students used whiteboards to work through another stoichiometry problem. A lot of students left with much more confidence than they’d started the day with.

Day 83: Electric Potential Difference & Whiteboarding

/ Marta R. Stoeckel / 2 Comments

Physics: Electric Potential Difference

In the past, I’ve motivated the need for electric potential difference in addition to electric potential purely through analogies to gravitational potential energy. Today, I tried an extension of the Modeling Instruction lab to map electric potential. I had students measure the voltage along a line in their tray of water with the multimeter’s ground attached to the negative lead of the power supply, then repeat with the ground attached to the power supply’s positive lead and the ground held somewhere in the middle. In the discussion, students agreed that the change in voltage is more meaningful than the specific value.

IMG_1604

Chemistry: Whiteboarding Problems

Students struggled with the stoich problems I left them yesterday, so we took some time to go through the first part of one. I tried to be very explicit and specific in bringing up previous labs or activities that used each skill, and that seemed to help students make connections. Students then continued the problem in small groups working on whiteboards. I need to do more whiteboarding problems in this class; the whiteboards really helped students function as a cohesive group, which is really not surprising.

IMG_1603

Day 82: Mapping Electric Potential & Stoich Practice

/ Marta R. Stoeckel / Leave a comment

Physics: Mapping Electric Potential

Students used Plotly to make contour maps of the data they collected yesterday. I was out on a field trip, so students followed along with a video I made last year. Based on my sub’s report and what the students I ran into said, the video went much more smoothly than when I’ve tried to give live instruction since students could pause and rewind the video to make it go at their pace. Tomorrow, we’ll do some talking about the results.

Electric Potential in a Water Tray- Pennies in Corners (1)

Chemistry: Stoich Practice

I left students two stoich problems broken up to try and help them think conceptually about the process. According to my sub, students struggled with the problems. Tomorrow, I’m planning to spend a lot of class time discussing the problems.

Day 81: Mapping Electric Potential & Stoich

/ Marta R. Stoeckel / 1 Comment

Physics: Mapping Electric Potential

Students collected data for the Modeling Physics lab on mapping electric potential.

IMG_1601

Chemistry: Stoich

Students finished the lab from Friday. The idea was to work through a stoichiometry problem, using nuts, bolts, and washers to represent atoms. My goal was to get students to think concretely about the process so that the math would make more sense. While students got closer to understanding the process, almost none of them saw the connection between their materials and the math they were doing. I need to re-work some of the questions and directions to explicitly prompt them to use the materials at key points. I also need to think about how I could have students use the manipulatives to answer the most frequent questions I got, so I can give them that nudge next time instead of focusing on the math.

IMG_1602

Day 80: Projectile Launchers & Return to Stoich

/ Marta R. Stoeckel / Leave a comment

Physics: Projectile Launchers

Students tested the final versions of their projectile launchers today. I picked random target distances in three different ranges, and groups had to pick one target to try and hit. I really enjoyed seeing the creativity in the materials students used. On group built a basic launcher out of K’Nex and decided to take a slushie break as they tried to come up with something to hold the ping pong ball, only to realize the lids from their slushies were the perfect size and shape. They also decided an adjustable height would make it easier to hit the target and came up with attaching the launcher to a music stand.

While students applied a lot of good data analysis to the project, the connections to energy and projectile motion weren’t as strong as I’d like, which I think has a lot to do with the way I broke up the project. I tried to squeeze energy into the two weeks between the start of tri 2 and winter break, and the project ended up bleeding into electrostatics. Next year, I may try starting the project with projectile motion, then working the redesign into the energy unit. There will be some administrative challenges, since the project will be split across two terms and a lot of students switch class periods, but I think it will pay off with students seeing a stronger connection to the physics content.

IMG_1595

Music stand, K’Nex, and a slushie lid

Chemistry: Return to Stoich

The next unit covers percent yield and limiting reagents, but scores were low enough on the assessment I gave before winter break that I want to revisit stoichiometry before we try any percent yield problems. Today, students started a lab to predict masses for an imaginary reaction using nuts, bolts, and washers in place of actual atoms. I wanted to give them something they could manipulate and measure very directly to get some conceptual understanding of stoich before we try any more problems. I wrote the lab with the intention of helping students work piece by piece through the process and questions frequently rely on information from a previous answer. A few groups, I think in an effort to be collaborative, tried to divide and conquer, and the students working on the later portions of the lab found they were stuck. Before we finish the lab next week, I’m planning to have a conversation with them about the shortfalls of the divide and conquer strategy and to come up with some more effective collaboration strategies.

IMG_1599