IMG_20121219_14145969 Some lovely kinematics graphs in preparation for tomorrow’s assessment.



Applying the Model


67 With some effort, students got through a couple of problems from one of Kelly O’Shea’s packets. There is still a lot of confusion on units, but I am trying to blast through the rest of CAPM this week and planning to start unbalanced forces after break. Wish me luck!

(The rectangular area is obviously not 91 m, but the girl who wrote 16 was on the opposite side of the board from the girl who was writing most of the work. Similarly, the triangular area is not infinity, but 8 m.)





66 Today some conceptual students did their first “practicum.” They timed how long it took the slow-acceleration disk to roll one meter down its ramp. Then they had to determine how fast it had been going when it passed the 1-m mark. While they timed it, I took video. While they debated how to find the answer, I did video analysis. They told me the answer was 0.16 m/s and then Tracker told me the answer was 0.164 m/s. So I told them that they got it right. They were a little stunned, I think, and I hope they were also proud of themselves for doing it. Next step: more complicated questions.


Coming to a stop


64 I skipped yesterday. Today we were working on accelerating situations. The photo was taken of the interactive whiteboard after going over a question. One class totally got it. Another class totally didn’t. One class hasn’t gotten there yet, and half of them have been in “Keystone Exams” yesterday and today, so we’ll have to do some catching up. Maybe tomorrow, when over 200 kids from our school go to the local DECA competition! (December is not a great month for powering through curriculum.)




62 Today the conceptual classes were learning to enter formulas into Excel to get the computer to do multiple tedious calculations.


Preliminary Graphs


58┬áSo, the data from the videos is not bad! Not everyone has actually managed to collect the data yet, however, as some students have technical difficulties. I’m always amazed when students can’t figure out how to find a file or save a file. I expect by the end of the year my students will have it figured out! I have found that it is important to have all the kids doing individual work for things like this, or only one kid from each group will learn how. One year I had students join my class mid-year who had somehow managed to always get others in their groups to do their work. My kids straightened them right out in terms of using the computers!


Speeding Up

57 We are starting constant acceleration particle model (CAPM) in the conceptual classes, and this is the first time I’m doing CAPM with students who know the difference between balanced forces and unbalanced forces. Another first is doing the paradigm lab using video analysis, so we started with each group making a video to analyze with a different number of bricks creating the slope. I use the apparatus I learned to make from Rex Rice when I took the Modeling Instruction workshop in 1997. It’s a disk made of particle board with a couple of golf tees for an axle. It rolls surprisingly slowly down a ramp made of two pieces of conduit, held at constant separation by two pieces of 1×2 with equidistant holes drilled in it. In the past I’ve had students mark the conduit with dry-erase markers and use stopwatches for timing. I’m hoping for better data this year, as well as teaching the students to use video analysis.