Properties of Matter

Day 71: Board Meeting, Practical, & Density Again

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AP Physics: Board Meeting

Students whiteboarded their graphs from yesterday’s video. Once I had my 2nd hour find a class average for the slopes of their vertical velocity vs. time graphs, everything fell beautifully into place and there were even gasps when one student sketched a free-body diagram. In my other hour, a lot of groups skipped the directions for making the v-t graph and tried to take shortcuts that didn’t work, so I had to step in a little more. This reinforces my thoughts yesterday that I should have spent some time discussing the midpoint method.

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Physics: Unbalanced Forces Practical

Students started a practical to predict the time it will take a cart to roll down a ramp given the cart’s mass and the ramp angle. For the first time, I had several students ask if I could just do a diagram or calculation for them, so I left the pen I usually carry at my desk and kept my hands in my pockets to avoid encouraging that.

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Chemistry Essentials: Density Misconceptions

Today, I have students blocks of the same material, but different volume, and asked them to determine whether volume affects density. A lot of groups had trouble funding the volume with a ruler, rather than later displacement, so I should have spent a little more time on a pre-lab discussion connecting yesterday’s volume measurements to today’s.

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Day 70: Projectiles, Forces Reintroduction, & Density

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AP Physics: Projectiles

Students did an activity on Pivot Interactives to watch the motion of a projectile from three different vantage points and produce position vs. time and velocity vs. time graphs. From what I saw, most groups got pretty good results. This was the first time students saw the midpoint method for finding slope of a curve, and I think I should have spent a little more time introducing that. We can have some discussion about it tomorrow.

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Physics: Forces Reintroduction

Especially because a lot of students really struggled with the forces assessment right before break, we started this week getting back into the swing with some problems similar to what we worked on right before break. Before break, I was also seeing more and more students getting off-task during time with their groups, so I spent some time sharing my observations and having some discussion about how that fits with what it takes to be successful in a class like this.

Chemistry Essentials: Does shape affect density?

I had students determine whether the shape of a block affects its density using a set of aluminum blocks with different shapes, but the same volume. Last tri, I’d asked students to predict the shape of the mass vs. volume graph, but it was tricky to collect class data and the graph was kind of boring since I didn’t have much variety of volumes. This approach got the same misconceptions out on the table, but gave more meaningful results.

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Day 69: Quizzes Galore

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Today is the last day before winter break.

AP Physics & Physics: Quiz & Mystery Tubes

AP quizzed over conservation of energy while regular quizzed on Newton’s Laws in 2D. Afterward, I got out the Mystery Tubes rather than starting a new topic. Students were a little fried since they had tests in just about every class, so I think they appreciated the chance to do something low-stakes after their quiz. My students were definitely loopier than usual, and that lead to some creative models of what’s inside the tubes. Next year, it might be worth putting a lab practical on this day instead of a typical quiz.

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This bug’s name is Todd. He lives inside the tube and moves the ropes.

Chemistry Essentials: Mistakes Game & Quiz

There was only time for one group to present their board yesterday, so we continued the mistakes game today before students took a short quiz on density. The mistakes game was fairly chaotic, but there were also some really good questions. I need to put in some more time working on norms for discussion, but I’m hopeful they will be able to have some good whiteboard discussions.

Day 67: Video Analysis, Speed Dating, & Density

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AP Physics: Video Analysis

Students continued working to determine whether a bouncy ball dissipates most of its energy from impact or from air resistance (I’ll have an article about this activity in the January issue of The Science Teacher). Today, students used LoggerPro to analyze the videos they made yesterday and collect evidence. There were a lot of great conversations about connections between energy and motion, which is exactly what I’m after with this activity. Most students had a draft of a CER about where the energy was dissipated by the time they left class.

 

Position vs. Time Graph
Velocity vs. Time Graph

Physics: Speed Dating

As part of my effort to focus on lowering the social stakes in my class, I had students do some whiteboard speed dating to go over yesterday’s goal-less problems. There were a lot of great conversations; the best part was how many students I heard asking “How do you know?”. My 1st hour in particular did a great job of finding and correcting mistakes in each others’ work. I also am continuing to talk about my pedagogical choices more than usual, which seems to be helping students go along with what I’m asking and hold each other accountable for participating. Particularly in my 1st

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The units got fixed on the next rotation, but I forgot to snap a new photo

Chemistry Essentials: Density

We discussed the results of yesterday’s lab to get to a definition of density. I skipped doing a true board meeting because, with break looming, I was worried about time, but students didn’t have as solid a mental model of density as I would have liked when they were working on the worksheet. It was a good reminder that pedagogical shortcuts have their cost.

Day 66: Missing Energy, Goal-Less Problems, & Mass vs. Volume

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AP Physics: Missing Energy

Students started working on an activity to determine whether a bouncy ball mostly dissipates energy due to air resistance or due to the impact with a table (I’ll have an article on this activity in the January issue of The Science Teacher). Today, students worked on sketching LOL diagrams and velocity vs. time graphs for each explanation, which lead to some good conversations about the connections between energy and motion. Each group also recorded a video of a bouncy ball that they’ll analyze in LoggerPro tomorrow.

Putting textbooks to good use
In-progress WB

Physics: Goal-Less Problems

Students worked on some goal-less problems for Newton’s 2nd Law in two dimensions. I was very explicit with my students that I use them to make it okay to start a problem without knowing where you are going. We also spent some time discussing key steps students should take (like deciding whether the forces are balanced or unbalanced, drawing and annotating diagrams, etc) which helped a lot of students see where to start.

Chemistry Essentials: Mass vs. Volume

Students worked on finding a relationship between the volume of water and its mass. I had students design their own procedure for the lab and I think they could have used more pre-lab discussion; I usually keep the pre-lab pretty short in favor of doing a lot of coaching lab groups, but the class is bigger than usual this year and I was spread pretty thin, which in turn fed some classroom management issues. I’ll need to keep that in mind for future labs.mass vol.jpg

Day 64: LOL Diagrams, Elevators, & Volume

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AP Physics: LOL Diagrams

We did the mistakes game again today (which my AP students now think of as standard whiteboarding in physics) for some problems with conservation of energy calculations. To avoid getting bogged down in the algebra, where most of my students are pretty strong, I had them put their mistake in the LOL diagram or writing the conservation of energy equation. Most groups worked on an accurate solution before they made their mistake, and one group did a nice job of setting up an equation for a problem where 10% of a baseball’s energy is dissipated before it reaches the peak of its path.

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Physics: Elevators

Students whiteboarded their work on Casey Rutherford’s elevator situations worksheet. A lot of students struggled conceptually with the direction of the net force, but seemed to resolve that by the end of the hour. I’m trying to lower the social risk of whiteboarding to get more engagement, so I gave each problem to two different groups, then had them meet and come to a consensus on a solution. Afterward, students did a gallery walk of all the whiteboards. We also discussed a video I made of a balance on an elevator to reinforce the worksheet.

 

Chemistry Essentials: Volume

Students filled geometric solids with water to find a relationship between the volume and the amount of water they could hold. I need to put some thought into how I introduce the lab; in particular, I don’t think my students have much concept of why this relationship is worth looking at. I know I can make use of that as we move into density, but I’m not sure how to frame the lab so they see a purpose in it up front.

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Day 63: Conservation Problems, Board Meeting, & Reaction in a Bag

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AP Physics: Conservation Problems

Students started working on solving problems with conservation of energy. There was a fantastic moment when I overheard a student say “I don’t understand number 3 yet; I need to draw my LOL diagram.”

Physics: Board Meeting

Students discussed the results of the 2nd Law lab from earlier this week. I put more pauses into the whole-group discussion than usual for students to talk with their lab groups about some question and was very conscious of asking for claims the group, rather than the individual, had come up with and made explicit those claims were rough drafts. This seemed to ease some of the fears about speaking up.

Chemistry Essentials: Reaction in a Bag

Students reacted calcium chloride, sodium bicarbonate, and bromthymol blue in a Ziploc bag. to see another example of conservation of mass in a reaction that forms a gas. Next time, I might combine this lab with the Alka Seltzer one to make a more involved exploration of whether gas has mass. Aside from this feeling more like a true chemistry lab than the Alka Seltzer one (students definitely connect goggles with “real” chemistry), that may give the opportunity to go into questions such as which was the better method of capturing the gas or whether all or some gasses have mass.

gas

Day 63: Bar Charts, Board Prep, & Particle Diagrams

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AP Physics: Bar Charts

Students whiteboarded yesterday’s problems for the mistakes game. In both my classes, students were generally excited to do the mistakes game and I contributed almost nothing to the discussion, which was fantastic. Afterward, we took a few minutes to use some thermal camera images to see examples of energy dissipated by friction, including a photo I took of my car after driving it.

Physics: Board Prep

I’d planned to have the board meeting today, but we ended up just prepping whiteboards today since enough groups had issues with their data that I think it would have been tough to have a good discussion. I tended to let poor data slide last tri, since it was easy enough to recover during the board meeting, but I think a lot of groups are counting on being “that” group during the discussion. I think having those groups re-do their data collection today helped set the expectation that they shouldn’t plan on being “that” group.

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Chemistry Essentials: Particle Diagrams

Students worked on a worksheet to practice drawing particle diagrams. The students who’ve been engaged in the labs so far were able to breeze through the worksheet and had some good discussions along the way. I’ve got more students than last tri, whoever, who checked out during those activities and had a lot of trouble with the worksheet as a result. I need to think about how I will interrupt the vicious cycle that is starting for those students.

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Day 62: Systems, Newton’s 2nd Law, & Does Gas Have Mass

/ Marta R. Stoeckel / 1 Comment

AP Physics: Systems

Students worked on a Modeling Instruction worksheet that emphasizes how changing the system changes the LOL diagram. A lot of students very naturally connected this to the SOS diagrams we’d done earlier in the year and how changing your system can affect whether there is any impulse.

Physics: Newton’s 2nd Law

Students used a half-Atwoods machine to collect data for how the force on a cart affects its acceleration. I ended up wishing I’d spent a little more time on the pre-lab; a lot of groups lost track of what they were measuring and how that connected to the purpose of the lab. Since I’m seeing low engagement during whole-class discussions, I’m thinking about how I could have students do some of the pre-discussion in their lab groups, instead.

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Chemistry Essentials: Does Gas Have Mass

Students measured the mass with a reaction of water and Alka Seltzer to decide whether gas has a mass. They did the reaction once in an open test tube and once with a balloon on top. While the balloon clearly leaked, there was significantly less loss of mass with it in place. I didn’t ask for particle diagrams on the lab handout, but I think that would have helped students think through what they expected and why.

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Day 61: Bar Charts, Mistakes Game, & Burning

/ Marta R. Stoeckel / 1 Comment

AP Physics: Bar Charts

We discussed the results of yesterday’s lab in order to define kinetic energy, then I showed them the derivation for elastic potential energy. Since we’d already defined change in potential energy as the area of a force vs. displacement graph, I think I could have put that derivation on students. Afterward, I introduced students to LOL diagrams and set them to work sketching bar charts.

Physics: Mistakes Game

I love Kelly O’Shea’s mistakes game, but I’ve been having trouble getting my physics students comfortable talking as a whole class, so I decided to try lowering the stakes. I had them prep whiteboards as usual, but then they presented to another group, rather than the whole class. There were a lot of great conversations between groups and students were much more comfortable speaking up. Afterward, I gave students time to do a gallery walk of the post-discussion boards.

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Chemistry Essentials: Burning

Students burned steel wool on a balance to observe the change in mass. Afterward, we used Post-It notes to make histograms of the change in mass from both yesterday’s labs and the burning. Last trimester, I skipped the class histograms, but I think the helped this group to meaningfully interpret their results. I also got excited when a student brought up conservation of mass before I did, which I don’t manage as often as I’d like in this course.

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