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

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.

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

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

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 52: UBFPM Practical, CAPM Problems, & Lewis Dot Beans

AP Physics: UBFPM Practical

Students were tasked with finding the inertial mass of a lump of metal. While I left it open, students pretty quickly settled in to following the steps from their 2nd Law lab. In one of my classes, a lot of groups initially used the unknown mass to provide the force on their half-Atwoods setup, which has me thinking they were losing track of the significance of the measured quantities; I skipped over having them do an interaction diagram and free-body diagram on the original lab, which I’m betting would have helped.

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Physics: CAPM Problems

Students used whiteboards to revisit an earlier quiz on CAMP problems. I had them go through piece by piece, rotating who had the marker for each step. That seemed to help students feel a lot more confident on the problems. Tomorrow we’ll see if they can do them independently.

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Chemistry Essentials: Lewis Dot Beans

Yesterday, when we worked on formula writing, students were losing track of what the various numbers represented. One of the other chemistry teachers suggested I try Lewis dot structures with a manipulative, so today students used beans to check their answers to yesterday’s problems.

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Day 47: Board Meeting, Whiteboarding, & Atomic Models

AP Physics: Board Meeting

Students whiteboarded their results from yesterday’s lab. I forgot to remind my 2nd hour to zero their force sensors yesterday, which made for a good opportunity to talk about what the intercept means. They were initially bothered by the units on the slope of their graph, but the units of N/(m/s2) became really valuable when we made a “for every” statement about the slope; interestingly, a lot of students phrased their “for every” statement in terms of how the acceleration changes for every 1 N of force, even though that required inverting their slope. I thought about having students plot acceleration on the vertical axis, especially since the College Board’s formula sheet gives a = F/m, but I think the mass pops out more nicely when force is on the vertical. I may still flip the axes next year since acceleration on the vertical would fit better with how they talk about the graph.

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Physics: Whiteboarding

Students whiteboarded their answers to last Friday’s problems. We spent a long time on a problem about using a log to hold a book against the wall, and there was a lot of great discussion about what that force should be and why, as well as whether there should be any horizontal forces. I think a lot of students don’t see that discussion as productive, but I heard a lot of great physics talk.

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Chemistry Essentials: Atomic Models

Students shared the information on the atomic models they looked at yesterday. They were surprised by the gap between Democritus and Dalton and were also very interested in the personal stories. I tend to skip past those, since most of the people the state standards call for are white guys, but its probably worth having some reminders in my class that science is done by people who live in a particular place at a particular time. Maybe next time, I’ll do a little more background research to try to come up with some other names, especially women and people of color.

Day 46: 2nd Law Lab, Board Meeting, & Atomic Models

AP Physics: 2nd Law Lab

Students started collecting data for a relationship between force and acceleration. A few students took out their formula sheet to get a preview of what the equation should be; it was interesting to listen to their conversation on what they expected the graph to look like and whether their data was consistent with the equation they expect to need.

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Physics: Board Meeting

Students whiteboarded their results for the spring lab. They are getting better at “translating” lines of best fit into physics by selecting meaningful variables and putting units on slope and intercept. It was also clear in the discussion that students are gradually making more connections between the graphs and the reality of the lab. When discussing the intercepts, there was a great moment where a student speculated whether gravity could be contributing to the intercept, which lead nicely into comparing the vertical and horizontal springs.

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Chemistry Essentials: Atomic Models

Students worked on a jigsaw for the history of atomic models. This was a nice opportunity to talk about what we mean by a model in science since we are looking at how models of the atom evolved over time. I asked groups to name some of the evidence used to support each atomic model, and students had a lot of trouble with that. I think part of the issue is a lot of students are still shaky on what makes something evidence and part of it is there’s a lot of background knowledge required to make sense of the evidence used in many of the atomic models.

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Day 102: Gallery Walk & 2nd Law

AP Physics: Gallery Walk

I ended up having students do a gallery walk for yesterday’s problems.

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Physical Science: Newton’s 2nd Law

Students worked on a version of the modified Atwood’s machine lab for Newton’s 2nd Law. While I have students make a graph, we don’t go much deeper than whether each relationship is direct or indirect. I spent more time on the pre-lab discussion today than I have for most labs with this group, and I feel like that paid off with more confidence while they were actually working in the lab.

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Day 42: Mass & Comet Orbits

AP Physics: Mass

Students finished the lab practical we started on Thursday where they used a modified Atwood’s machine to find an unknown mass. Today, once they had an answer, we checked their result using a spring scale. One of my goals this year is to work on hearing from every student, so I tried posting three questions about the lab (one for each group member). Then, before groups could check their result, I would roll dice to decide which group member had to answer each question. Since there are three students in each group, I was able to hear from every student. Groups did a really nice job of making sure all three group members could answer all three questions, which is exactly what I hoped would happen.

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Earth Science: Comet Orbits

Students finished up yesterday’s lab contrasting Mars’ orbit with Halley’s Comet’s orbit. A lot of groups were surprised when they realized that the patterns from Kepler’s Laws worked equally well for both orbits, especially when they used mass as a proxy to compare the areas of two sections that represent equal times. Next time, I might see if I can get my hands on some card stock or other heavier paper to make it a little more convincing that the small differences are negligible. I also will probably re-work my Kepler’s Law introduction to include Halley’s Comet right off the bat, rather than waiting until we introduce comets.

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Day 41: Central Force & Comet Orbits

AP Physics: Central Force

Students used a Direct Measurement Video of a weight on a rotating table to find a relationship between force and tangential velocity. One of the first questions on my activity was to draw a free-body diagram of the weight and determine whether there is any net force. A lot of groups had some great discussion as they tried to rectify the fact that the table rotates with a pretty constant speed with the fact that their free-body diagrams showed a net force on the weight. There were also some groups that asked questions like how the speed of the banana compared to the speed of the weight, bringing them back to a Direct Measurement Video of a rotating disk we’d used earlier in the year.

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Earth Science: Comet Orbits

A major theme this week is comparing different kinds of solar system objects, so I decided to take an idea Michael Lerner gave me last week and have students compare the orbit of Halley’s Comet to Mars. I used an ellipse drawer to give students the orbit of both objects, then had them start by making some observations. Today, most groups only had time for the qualitative questions about the two orbits.

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Day 40: Mass & Craters

AP Physics: Mass

Students worked on a lab practical to find the mass of an unknown object using a modified Atwood’s machine. My plan is to use spring scales to verify the mass the determined, then use this to introduce the difference between inertial mass and gravitational mass, but time got tight and most groups need a little longer to finish their calculations.

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Earth Science: Craters

During yesterday’s lab, it quickly became clear that my students did not have much sense of how craters are formed. Today, I got out some trays of sand and an assortment of marbles and we explored how mass and impact speed affect the crater size. I was really excited when the groups who finished early started asking new questions, like how the depth of the sand or angle of impact changes the crater, and coming up with experiments to answer those questions. This is why I love freshmen! We also dropped a shot put into a bigger tray of sand and got some slow-motion video just because its cool.

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