Passion for Physics and Pedagogy

I was so excited to try this, I've thought about doing it for years but seemed to never have the time. My AP C students do an Atwood's Machine lab that I've adapted over the years. The original lab came from my predecessor who had students use two identical hanging masses and one small mass. I've been using 200 grams for the "identical masses" and a 20 gram mass as the small one. The students used a known fall height and stopwatch to determine the acceleration with the small mass on one of the larger masses and then with the other in case the two identical masses weren't actually the same. They used a smart pulley with a Vernier photogate so the second part of the lab asks them to find the slope of the velocity-time graph as another way of finding the acceleration. The second day challenged students to find the mass of one penny using the same method. Instead of the small mass, students used a stack of four pennies (being sure to have them all before or af...

There is a problem in my 10th edition of Halliday, Resnick & Walker that asks students to determine the force read by the spring scale in this image: Prior to trying this problem, students are asked to complete this desmos card sort , originally written by Brian Frank. I asked students to complete it individually, without collaboration, which is hard for them. I tell them that I'm not grading it for accuracy. Then students attempt this textbook problem in groups. The salami in the problem is 11 kg , which I start the discussion by putting in context for them. We joke its more like a holiday ham than a salami.  As we review the problem, students have no problem agreeing the scale reads 110 N (when g is 10 m/s^2) in the image (a) and (b) but start to disagree with their answers for (c). I ask students to raise their hands to vote if they think the spring scale will read 0 N (the misconception that the forces balance and therefore the scale reads 0 N), 110 N (the weight of one sal...

 I was inspired by this Darek Dewy Twitter/X post  he used to demonstrate the contact forces between two boxes using a balloon. He labeled one box "H" that was "Heavy" and the other "L" for "Light." A constant force was applied by a mass attached by a string over a pulley. You can see the balloon being squished between the two boxes, more so when the lighter box is trying to push the heavier one than the reverse.  The first time I tried this I planned to demo it. Then I remembered I had plenty of bricks and plenty of blocks. I put a brick and a block on a tray with a partially filled balloon (so that it fits better between the two) and set them out on my student tables.  I invite students to make a sideways sandwich with a brick on its long side, the balloon and then the block. I ask them to push the system from the block side then from the brick side and make observations. Students experiment for awhile and observe the balloon squish different a...

 When I started teaching, the veteran physics teacher had these cars for a particular lab he called "two speed shifters." They are wind up cars that when released, start moving at a slow, nearly constant speed, then shift and accelerate.  A piece of string was tied and taped to the top of the cars that would run over a smart pulley attached to our Vernier photogates. After the car was wound up and put near the photogate, the string had to be pulled back so that it would move against the pulley while the car pulled the string out. The set-up is specific, and sometimes finicky, but provides a very interesting graph for students to analyze. There are more specific details about the "how" below.   Students would focus on the velocity-time and position-time graphs. They would learn how to use the tangent line function on the position-time graph to find the spot where the slope started to decrease. They look at the velocity-time graph at that same time to see that the vel...

Moments before the start of school on the second day I realized I had not created a new seating chart for my class. Typically, I allow students to sit where they want on the first day of school but create a seating chart on the second. I use the random seat generator within my Learning Management System (LMS) but it isn't perfect and I have to make adjustments for students that need to be near the screen, my audio amplifier or who should most definitely not be next to their friends. My classroom only has movable lab benches for student seating, 9 tables that fit 4 each and they are all full in my AP classes.  Michael Freeman has a visibly random group generator ( here ) which has a lot of versatility in terms of group sizes and labeling. But I also needed help learning names (California class sizes of 35+ means a lot of kids across 5 sections) so I wanted name cards. I ended up writing their names on an index card folded in half. I used a different color or each period, going in ra...

It's hard to understand all the nuances of someone else's job, to understand exactly what they do day in and day out, teaching included. My friends and family see me grading and understand that, they can see me building something or buying things for my classroom and understand the need for that. Yet one of the hardest things for non-teachers to understand seems to be lesson planning.  "But you've been teaching awhile, can't you just do the same thing as last year?" "If you know the material, why do you have to write down how you'll lecture?" "Didn't you do that lab last year? Why change it?" One of the great misunderstandings of teaching is that while repeatable, it is rarely the same from year to year. There are some activities I have done every year while teaching the same course, there are some I did once and never again. Even the ones that are a "staple" in my curriculum have gone through many, many iterations. Some c...