Day 142: Assessment, Reflection Lab, & Backwards Problem

AP Physics 1: Assessment

Students took their quiz over angular momentum, and we have now officially finished content. Wooo! 2 class days to spare!

Physics: Reflection Lab

We got out the geo mirrors and some plane mirrors to start exploring reflection. I like to start each optics topic with a lab making qualitative observations. The instructions I gave students today need some work; students had trouble parsing the wording to make meaningful observations.

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Chemistry Essentials: Backwards Problem

As a quick warm-up before taking the limiting reactants quiz, I had students whiteboard what I called a backwards problem. I gave them a reaction and told them what should be the limiting reactant, then had them sketch a particle diagram for a situation showing starting conditions that would lead to the right limiting reactant.

A few kids were feeling stressed out about this quiz, so we also took a few minutes to revisit the reassessment policy, including the fact that I’m putting retakes into our normal assessment process, which helped lower the stakes and let students feel a little calmer about the quiz.

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Day 90: Angular Momentum & Mirror Mazes

AP Physics: Angular Momentum

Students used a Linear and Rotational Collision Direct Measurement Video to get some practice with conservation of momentum. In the first question, I asked students to determine whether momentum was conserved in a certain collision using a calculation, and I was surprised by how many students struggled to understand the question. I might change up wording on some of the problems we did to explicitly have them state whether momentum is conserved or if there is an external force, similar to how I approach force problems by first asking students whether the forces are balanced.

I also asked some questions about whether momentum is conserved in collisions where the block starts to spin, and I heard some great conversations about uncertainty, external forces, and other big ideas that have me really looking forward to tomorrow’s discussion.

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Physical Science: Mirror Mazes

Students used what they know about refection to solve some mirror mazes. I had some where students were given the placements of the mirrors and had to place the target and others where they were given the target’s location and had to place the mirrors. Since we haven’t done much with ray diagrams, this seemed to really solidify what I mean by the path of light.

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Day 88: Collisions & Mirrors

AP Physics: Collisions

Students finished collecting data to compare momentum before and after a collision of two carts, then had just enough time to talk through results. I just gave students a data table from the Modeling Instruction curriculum, but I think my students could have handled something more open-ended as long as I can plan how I will make sure students get a good variety of collisions. I ended up falling into a pretty teacher-centered “discussion” after the lab to limit how much time we spent, but I think we missed out on a really good opportunity to talk about uncertainty and assumptions. Next year, I might have each group do just a few collisions so we spend more time discussing the results.

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Physical Science: Mirrors

I gave students three questions about the images formed by a mirror and tasked them with writing a CER for each question. This is the least structured lab I’ve given students so far this year, which made some students nervous, but I was pleased with the results. I had students whiteboard their CERs so we could have some discussion, but I had students stay at their lab tables and a lot of students kept going back to small group discussions. I think this was because I’ve established a very clear routine where the desks are for whole-class discussion and the lab tables are for lab group discussions. Next time, I’ll probably keep the discussion in the lab area, but have students stand up and move away from their tables to get the physical cue that its time to shift focus to the whole class.

Day 46: Mistakes Game & Reflecting Telescopes

AP Physics: Mistakes Game

We played Kelly O’Shea’s Mistakes Game using some problems with a central net force. Its great to see my students getting more skilled at discussing physics, which means I’m doing very little to keep the conversation moving. We had some particularly good discussions about a problem about the forces on a roller coaster car as it goes over a hill and about the forces on a yo-yo as it swings in a vertical circle.

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A whiteboard for the roller coaster problem

Earth Science: Reflecting Telescopes

Students played with curved mirrors to get some ideas about how mirrors are used in telescopes. I also got out some electric candles and tasked students with projecting the candle on a sheet of paper. They struggled with that step, but it was great to see their reactions when they got a nice, sharp image of the candle “flame”.

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Day 156: Mistakes Game & Speed Dating

Physics: Mistakes Game

We played the mistakes game with ray diagrams for curved mirrors. Its been a while since we last did that, and a lot of students were excited to play.

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Chemistry: Speed Dating

We did some whiteboard speed dating with empirical formula problems. By the end of the hour, most students were feeling pretty confident. Just to solidify that confidence, we did a “practice pop quiz” where I put up a problem and had students work through it in quiz-like conditions, then went through the answer and had some conversation about the next steps for people who didn’t do well on that quiz.

Day 155: Ray Diagrams & Empirical Formulas

Physics: Ray Diagrams

Students took their first stab at drawing ray diagrams for curved mirrors. A lot of students made liberal use of colored pencils to keep the different rays straight.

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Chemistry: Empirical Formulas

I introduced students to empirical formulas, focusing on them as a new layer to the percent composition work we started on Friday. Students were pretty successful with the new skill.

Day 154: Curved Mirror Equation & Percent Composition

Physics: Curved Mirror Equation

Students collected a little more data from yesterday’s lab, then whiteboarded the results to get to the curved mirror equation. The graphs were not as consistent as with some labs, but students were still able to get where I wanted them to.

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Chemistry: Percent Composition

Last trimester, a lot of my students struggled what they knew about percents from their math classes to percent composition in chemistry. This tri, before giving any instruction, I asked students to  answer a few questions like “What percent of this class is male?” Giving students those questions, then asking them to talk about the process they used, got students to bring the math into the class themselves, which lead students to make sense of percent composition much more easily than last trimester.

Day 153: Focal Length & Whiteboarding

Physics: Focal Length

Students started collecting data to produce a plot of image distance vs. object distance for a concave mirror. A lot of students were trying to complete the lab with the mirror, candle, and screen all in a single line, so tomorrow I’ll need to review the directions and give a little more time to collect data.

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Chemistry: Whiteboarding

Students whiteboarded yesterday’s problems, then we played the mistakes game. Students seemed pretty confident by the end of the hour, so hopefully tomorrow’s acids and bases quiz will go well.

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Day 152: Curved Mirrors & Neutralization 

Physics: Curved Mirrors

We started by whiteboarding yesterday’s reflection problems. Along the way, I had a student stand in front of a nice, long horizontal mirror while someone else held a whiteboard between the student and the mirror to show a blocked object can still form an image. Afterward, students started making some qualitative observations about curved mirrors. My favorite part was when students noticed the hologram mirror I had out and start puzzling through what was going on. Even once the opened it up, students were eager to try changing the setup to see what would happen and test their ideas. I think some students were legitimately excited when I told them we’d draw the ray diagram for it later this week.


Chemistry: Neutralization Reactions

Students practiced determining the products in neutralization reaction. I was pretty pleased when a student asked “Aren’t these just double replacement reactions?” Last tri, a lot of students struggled to connect one day in class to the next, so this tri I’ve been much more intentional about trying to help students make those connections, so it’s gratifying to see students looking for links between new and old topics unprompted.

Day 151: Mirror Problems & Antacids

Physics: Mirror Problems

Students worked on some planar reflection ray diagrams from the Modeling Instruction curriculum. They seemed to be getting some important ideas in place about the ray diagrams.

Chemistry: Antacids

Students had to design an experiment to determine which of several different antacids is the most effective. It was clear that my students had not had many opportunities to design their own experiments, so there was a little panic at first, but they were able to come up with a procedure with a little nudging. I used 3 M HCl and the pH didn’t budge much with any of the antacids, so we had some conversation about what it means to have an inconclusive experiment in science. The other chem teacher used 1 M HCl, and got some very noticeable changes in pH after using the antacids and was able to make a reasonable comparison.

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Not much change in pH