Day 9: Distance to Position in 10th Grade Physics or The Second Experiment in Two Days

Today was the second day of class for my 10th grade trimester class. I took a page out of Frank’s book and did the buggy lab twice with them.

Watching the girl sitting on the bench giving directions to the boys as the group took data the first day was kind of awesome.

When they came in today, I gave them a quick preview of what we would do: we started with a board meeting about our first experiment, then did the bridging activity about position, then we jumped back into the buggy experiment again. They agreed the experiment would take the most time, so they kept that in mind through the first two parts.

For a first board meeting, it went well. They nailed the similarities immediately (the graphs are all linear; they all “look the same”—start from the origin and “go up”; etc) and eventually got to the differences in slopes. At the end of the discussion, we did a brief meta-debrief and I noted how much I led it and how I’m hoping they will take more of that control away from me as we have more of those meetings. I also recapped what my general flow of that discussion had been (take a moment to look around, then talk about similarities and differences and what they each mean).

The bridging activity for position was quick and useful. I let them work for a few minutes, then got 5 or so different ways to say the position of one of the cars. Then I asked what the ingredients were in order to describe position. The answer they gave included two objects (the one you’re giving the position for and a reference object), a distance, and a direction. Perfect. The task of collecting positions instead of distances was pretty simple after that (way simpler than it is when I’ve done only position-time data), and only one group struggled with using positions instead of distances. (And to be fair to that group, I think they might have been the only one that went from negative position to positive position in the course of their data—that threw them off because they wanted to measure from when the cart passed the origin instead.)

The biggest hurdle today was in using the space well. I couldn’t set up in the hallway because the class met during a period that overlaps partly with another class period. The room isn’t really conducive to one big space, especially with all the desks out from the first part. And I had two completely different preps earlier in the day (and only one in that same room). So among all those factors, I did a pretty mediocre job of setting up the coordinate system for them and everyone was basically on top of each other.

IMG_1782 IMG_1783

They were amazing sports and still took great data quickly. One group knew their slope didn’t make sense because they had a fast cart, but their slope said it was slower than even the slow carts had been. I left them to work on it for a while and when I got back they had figured out on their own that they’d measured in inches instead of centimeters and had already fixed it. They’re a pretty awesome class.

So two experiments in two days for them. Not a bad start to 10 weeks of physics, right? Next class we will have our second board meeting, so I’m excited to see them take a little (or even a lot) of that discussion out of my hands. I have already seen them be scrappy, resourceful, clever, patient, and willing to make and fix mistakes. I think they’re ready for this.

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