# Day 137: Lots of Whiteboarding

AP Physics 1: Unbalanced Torque Whiteboarding

We did some mistakes whiteboarding with some torque problems. Students made great connections to what they already know about unbalanced forces, which is making it possible to move quickly through the topic.

Physics: Ray Diagram Whiteboarding

Students whiteboarded some ray diagrams from yesterday’s shadow lab. They made the connections I wanted them to make and were making sense of how the ray diagrams fit with what they saw.

Chemistry Essentials: Limiting Reactant Whiteboarding

We did some whiteboarding of limiting reactant problems emphasizing the particle diagrams as a problem-solving tool. I haven’t pushed the diagrams as much this year as in the past, and it showed on a quiz I graded earlier today. Now is time to start rectifying that mistake!

# Day 136: Board Meeting, Shadows, & Limiting Reactants

AP Physics 1: Unbalanced Torque Board Meeting

Students whiteboarded their results from yesterday. They quickly and easily made the connections I was after and the idea of rotational interia seemed to click well.

I did a quick intro to ray diagrams. I like to clap some chalk dust over the beam from a laser pointer to show the light travels in a straight line. This year, I followed up with clapping chalk dust over a flashlight beam to see the cone of light and motivate drawing multiple rays, which worked very nicely. Students then played with shadows and drew ray diagrams to explain their observations.

Chemistry Essentials: Limiting Reactants

Students worked on some limiting reactant problems. Based on some questions students asked yesterday, we also revisited a reaction we’ve done with magnesium and hydrochloric acid. I set up one flask with indicator and hydrochloric acid to use as a reference. In the other two flasks, I also added magnesium and tasked students with making observations to determine what the limiting reactant was in flasks 2 and 3, which they answered using a CER.

# Day 135: Pivot Angular Acceleration, FCI, & Limiting Reactants

AP Physics 1: Pivot Angular Acceleration

I am as part of Pivot Interactive’s Chemistry Fellows program.

Students used Pivot Interactives to find a relationship between unbalanced torque and angular momentum for several different bicycle wheels. I had them start by setting up a formula they could use to calculate the angular acceleration from the change in angular position and the time. My 2nd hour had a much easier time with this; I think the difference is they worked yesterday’s problems in small groups and quickly connected this task to some of the problems they’d done. My 4th hour had a sub yesterday who was a former physics teacher that decided to go through the problems as a lecture, so I think those students didn’t have as firm a grasp on the calculations.

Physics: FCI

Students took the Force Concept Inventory as a post-test. We normally give it before moving into simple harmonic motion, so they were a little rusty on thinking with forces, but I’m satisfied with the results.

Chemistry Essentials: Limiting Reactants

Students used nuts, bolts, and washers to start connecting mass to what I’d planned for them to see about limiting reactants yesterday. While both my sections were able to get through today’s activity without trouble, I need to figure out how to adjust for some issues yesterday. My 5th hour is co-taught, so my co-teacher ran the class and the majority of students easily finished yesterday’s activity and had the ideas I wanted them to have at this point. In my 6th hour, the sub decided to go over the answers to the accompanying worksheet as a lecture without projecting the simulation, which my students really struggled to follow. Several students helped themselves to a computer and worked through the activity as intended, and I’m having trouble getting mad at them for defying the sub. I think the activity with the simulation is worth doing, but between demand for the school computers and trying to keep both sections in the same place, I’m not sure how to give my 6th hour time in-class.

# Day 130: Whiteboarding, Problems, & Lab

AP Physics 1: Whiteboarding

We did some whiteboarding of last week’s torque problems. Students aren’t confident, but they are getting the hang of extended free-body diagrams and successfully solving problems. With the clock ticking, that will have to be good enough for balanced torques.

Physics: Problems

Students did some problems with standing waves. It was tricky for a lot of them to connect the wavelength to the length of the resonator, so that will be something to work on during whiteboarding tomorrow.

Chemistry Essentials: Lab

Students did a lab with magnesium and hydrochloric acid. We stuck with purely qualitative observations today and will get into the actual stoich tomorrow.

# Day 129: Problems, Standing Waves, & Problems

AP Physics 1: Torque Problems

I was much more teacher-directed today than I typically shoot for. I ended up walking students through how to approach balanced torque problems; students were pretty into the idea that they can pick a pivot point for the problem that lets them solve for different quantities. We had a few minutes at the end for some whiteboarding. While students aren’t confident yet, I think they are doing just fine on balanced torques.

Physics: Standing Waves

We went through a guided discussion to get at the patterns for standing waves using first a wave generator with a string, then a singing rod, and ending with a tuning fork. When there were some good points for small group discussion, I had students work in their packets, but I think it would have been better to have them use whiteboards.

Chemistry Essentials: Stoichiometry Problems

Students worked some stoichiometry problems. We stuck to whole number ratios so students could draw particle diagrams as a tool to work through the problems.

# Day 128: Problems, Tuning Forks, & Stoichiometry

I was on a field trip today, so had a sub.

AP Physics 1: Balanced Torque Problems

Students worked some problems with balanced torques. I wish I’d edited the worksheet to include some problems revisiting forces, but ran out of time last week. I’ll be interested to see if and how my students used the area model I showed them yesterday.

Physics: Tuning Forks

Students did a lab playing with tuning forks to start building some ideas about sound waves. There’s usually some good discussion that I’m a little sorry I missed.

Chemistry Essentials: Stoichiometry

Students started doing stoichiometry by using nuts, bolts, and washers to represent different types of atoms, making it possible for them to “see” how many moles they have and measure the masses very directly.

# Day 127: Board Meeting, Slinkys, & Molar Mass

AP Physics 1: Torque Board Meeting

We had our board meeting to get to the definition of torque. As expected, in the class where I had students plot the ratio of the forces on one axis and the ratio of the radii on the other, results were rough and I had to step in. In my other section, results came out beautifully and students were quick to figure out why their graphs had intercepts. I also introduced students to Brian Frank’s area models for torque, which students seemed to grasp.

We used slinkys to start figuring out some ideas about longitudinal waves. Students were pretty successful at noticing the things I wanted them to notice. As with transverse waves, we tied some ribbons on the spring to help track the particle motion.

Chemistry Essentials: Molar Mass Lab

I got out samples of several different materials, and had students weigh a sample and figure out how many moles they had. Not the most dramatic lab, but it was some good practice.

# Day 126: Levers & Whiteboarding

AP Physics 1: Levers

Students did a lab with levers to introduce torque. I usually take 3-4 days on lever labs, so tried to shorten it. In my 2nd hour, I had students graph the ratio of the forces on one axis and the ratio of the radii on the other; the results so far are looking messy, so I think I tried to accomplish too much with that approach. In my other section, I had half the class keep the positions constant and graph the two forces, while the other half of the class keep the forces constant and graphed the distances from the pivot. The results are looking really nice, so I think that was a better abbreviation.

Physics: Whiteboarding

We whiteboarded and discussed a couple of wave problems from TIPERs. Students seemed to find the problems pretty straightforward.

Chemistry Essentials: Gallery Walk

We did a gallery walk to go over Friday’s problems that combined balancing with molar mass. Students are starting to be able to shift away from the blocks we’ve been using for balancing and rely more on their particle diagrams, which is great to see.

# Day 138: Tic Tac Bounce, Board Meeting, & Problems

AP Physics: Tic Tac Bounce

As part of the toilet paper practical, I asked students to calculate the final velocity of their unwinding roll using a v-t graph and using an LOL diagram. The discrepancy between the two velocities prompted some good discussion, which lead nicely into Kelly O’Shea’s bouncing Tic Tac demo and the idea of rotational kinetic energy.

Physics: Board Meeting

Students whiteboarded their data from the snakey spring lab. There were still more groups than I’d like who had results that were definitely not an inverse relationship between wavelength and frequency. The big problem seems to be in finding the frequency; we haven’t made much use of that term, so I think students are not attaching much conceptual meaning to it, in spite of the pre-lab discussions. We also didn’t do as much as I usually do with position vs. time graphs for simple harmonic motion, which seems to be making wavelength a tough concept to grasp. Next year, I need to rethink my unit on springs and pendulums to build a better foundation.

Chemistry Essentials: Limiting Reactant Problems

Students worked on some written limiting reactant problems. It was a much tougher leap than in past years; this class isn’t as comfortable with using particle diagrams as a tool for thinking, and I think that made limiting reactants feel more like something new than a natural step in what we’ve been doing.

# Day 137: Toilet Paper Practical, Snakey Springs, & Limiting Reactant Hardware

AP Physics: Toilet Paper

Students finished working on the lab practical we started yesterday. Students did a lot of connecting ideas, which was great. I added a question asking students to calculate the final velocity of their unrolling roll using the velocity time graph and using energy, which I’m hoping to use to introduce rotational kinetic energy tomorrow.

Physics: Snakey Springs

My plan was to whiteboard yesterday’s lab, but most groups had either a linear or quadratic relationship between wavelength and frequency; a lot of students seemed distracted during yesterday’s pre-lab discussion, and I should have taken the time to bring their focus back rather than plowing ahead. We took a few minutes to talk about whether the graphs groups have make sense, then revisited the pre-lab discussion and re-did the data collection. I’ve had some other labs this tri we needed to re-do because of poor results, so I need to think about how to do a better job of making sure the lab goes well the first time around.

Turns out my heavy ring stands work well for holding one end of a snakey spring

Chemistry Essentials: Limiting Reactants Hardware

We revisited the nuts, bolts, and washers and the “reaction” used to introduce stoichiometry to explore more with limiting reactants. I had a few students who were bothered that there isn’t a simple rule they can always use to immediately identify the limiting reactant, but they were still able to see the kinds of approaches I wanted them to.