Today was the second day of the Balanced Forces Particle Model (BFPM), which I intro using Kelly’s rather brilliant method here. This is a picture of the whiteboard after one of the classes, we didn’t quite finish looking at the pattern but were able to leave my last classes’ on the board for tomorrow, where we will finish drawing out the connection between Forces and our former models, Constant Acceleration Particle Model (CAPM) and Constant Velocity Particle Model (CVPM).
As I was grading this years Exam 1 in my concurrent enrollment college level physics class I had a feeling that students were really rocking it compared to last year, so naturally I spent 1-2 hours on a Saturday night playing with the data. This box plot is, I think, the best representation, showing that all four quartiles increased. This is verified in that the mean had a statistically significant increase (p<0.05) and the standard deviation decreased from around 13 to 9.
I am in the process of writing a blog post about why I believe this increase of scores occurred, so you’ll have to wait a bit for that. The teaser is that it’s a kind of Standards Based Grading (SBG) implementation for a class in which I can’t really do SBG.
UPDATE: Here’s the blog post, When You Can’t Do SBG
Today Ben walked into my office with an assumption that students were making. They were working on problem 1c from Practice 1 in this packet, where a concrete block is being pushed with a hand, and there assumption was that the block sped up instantaneously and then moved at a constant velocity while the hand pushed. So Ben and I went back to the classroom and recorded a high speed video of a box being pushed, and the results above are pretty convincing that the box sped up. We want to make a better video with a large, heavy box, but this worked for the time being.
We are working on testing the effect of mass on acceleration for a cart down a ramp, and students are going to write a lab report for this lab. One group came up with the great idea to keep all trials on the same screen, giving great qualitative evidence that the acceleration is not affected by the mass.
I just finished up (I hope) this year’s BFPM packet, borrowed heavily once again from Kelly. I am particularly looking forward to whiteboarding the problem above, it’s going to be pretty tough for students. I’ve recently had a lot of luck writing problems based on images I find with simple Google searches like “Two boxes ramp physics.”
Today I built a reassessment day into our schedule. I have 74 kids in this class (in 3 sections), and I printed out 55 reassessments on 4 different learning targets! The gains they showed were impressive; approximately 80% increased their score and the other 20% showed some gains in understanding even though it didn’t change their score (I grade 2,1,0). More on my grading system coming soon on learningandphysics.wordpress.com!
Today I was gone, and students were investigating adding mass to carts going down a constant incline. They apparently took it to the extreme.
I got permission from my principal 2 years ago to join a student created FB group with students in my class and it is awesome for community building and quick announcements. If you are not familiar with groups, you don’t have to be ‘friends,’ so we can’t see each other’s normal FB activity, only what is posted directly on the group page.