Physics: The Qualitative Second Law Lab
A few weeks ago, I did this lab qualitatively for the first time in all four sections. Here are the images of the lab so you don't have to scroll on the older post...
- First, the students wrapped up some Fnet practice on the whiteboards (drawing force vector addition diagrams and determining the magnitude and direction of the net force). Basically, they did three problems producing work similar to what is shown below. The velocity vs time graph at this stage was qualitative only since the students didn't yet know how to relate a velocity vs. time graph to a force vector addition diagram (2nd law!).
- As they finished whiteboarding and were reading the instructions for the lab in their Unbalanced forces packets, I dropped off a ramp, fan cart, and extra masses to each table. One person from each group went to grab a phone from our cell phone spot for timing.
- They worked through the lab on their whiteboards with little to no questions. I did this four times as I have four sections and, other than groups that need universal encouragement, the students were able to work through it all without intervention. This is a pretty big deal, to be honest. Hands-on experiences so often lead to debilitating nervousness (amygdala hijacking as we've been learning in our PD sessions). But not this time!
- I had MULTIPLE groups come up with second law on their own. Happy sigh... Did everyone come up with it? No. But everyone made it through the lab and could explain how acceleration was impacted by changing mass and changing force. Win.
- The lab was super fast...20 minutes on average. I want to add the calculation of acceleration back in with the velocity vs time graphs. Some groups started doing this on their own which was awesome. This does bring me back into the analysis zone, but I think I can incorporate it in a low-stress kind of way.
- I want to possibly have the members of the groups that DO come up with second law help other groups get there too instead of me.