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Paradigm Lab Assessments

July 14, 2017

This year, I joined an Honors Physics class in the 3rd quarter, and one of the things it reminded me of what both how vital paradigm labs are to modeling physics, and how tempting it can be for students to sit on the sidelines and wait to be handed the information they think they need. In one instance, we were trying to figure out what factors affect the net force acting on an object moving in uniform circular motion, and students were releasing pendulums and measuring the tension force of the string to see how the mass, speed, and radius of the path affected the tension force at the bottom. When first discussing how to approach the experiment, I saw the not too unfamiliar situation where a couple of students seemed to be driving most of the discussion, and many other students seemed to be just waiting for them to get to the point where the teacher said: “great, now go do the experiment.” This, naturally, left them very shortchanged when it came to understanding what they were investigating, and really ill prepared for the board meeting to follow.

I find board meetings to be both fantastic and frustrating. As much as possible, I just try to sit back, take notes and watch what is happening. Sometimes, I’ll feel like an important point is being left out, or a question isn’t being asked, and right as I’m getting ready to jump in, another student will save me from needing to intervene and raise the issue. I’m always astounded by the ideas students come up with in these discussions. But I also find that there’s a significant group of students who can be quite lost in these discussions. By the time you get to late in the year, those students have become seemingly comfortable with being lost—they’re just patiently waiting for the “smart” kids in class to figure it out and tell the class the formula they need to know to be able to solve the problems in the packet.

This is entirely my fault as a teacher. It is quite possible to succeed on all our assessments knowing nothing about the work done during the paradigm lab itself if they are comfortable working with the “equation.” And yes, this is part of the reason why some students can come to the notion of thinking in models so late, since they don’t av apply the idea in the paradigm experiment, and instead are just waiting on the result.

So what’s to be done? First, I’d like to point out that it wasn’t always this way in our classes. There was a time when we taught from PSSC physics and used their infamous multiple choice tests that pushed students to extend their reasoning from the labs they conducted. For instance, following the N2L experiment we did where students pulled skate carts with springs, we would ask this question

Screen Shot 2017 07 13 at 11 40 08 AM

This question pushed students to go back to the understanding they developed in lab and think carefully about what they were doing and how each of the points was generated by the same cart experiencing the the pulling of a different number of equally stretched bands. These questions were hard, and more often than not, students would miss them on the first try, and in these pre-SBG days, we’d have to do things like offer partial credit corrections for students to recover some credit.

I’d love to have questions like this as an integral part of the lab experience in our class now, and it’d be great to add a standard to about conducting and understanding experiments that establish the model. My problem is that under our current approach to SBG, I would likely have to generate a ton of questions for each experiment/model to give students the opportunity to reassess to mastery, and that seems very daunting.

Another way to have students demonstrate understanding of a lab would be to have them write lab reports, and I think there could be great value to this. But they are a challenge to grade, a chore for students to prepare and would likely entail a sacrifice of homework and class time that would lead to covering even less content.

Paradigm assessments

Instead of lab reports, I’d like students to focus and reason about a few critical ideas and questions that came up in the lab discussion. Keeping in the spirit of SBG, I’d like for them to be able to make mistakes and improve their understanding of these points, and I’d like for students to recognize that the best way to be successful at this task is to deeply engage our board meetings.

I’m thinking of creating paradigm assessments that would come from my observations and questions in the board meeting. Here’s a pretty artificial one that I cooked up for the buggy lab.

View this document on Scribd

The key to this assessment is that I’d like for it to be short (no more than a single page) and focused on reasoning about the lab. I’d also like it to get students to think about how to revise and improve their work, and why we ask them to do all the things we do like labeling your columns or including a line of best fit.

If I’m taking good notes, it should be relatively easy for me to find a point or two to build an assessment around each lab discussion.

As for grading, I think I could hand this out on the day following the lab discussion and ask students to complete it at home. If you reach a threshold for mastery of this that I’ll have to define, you get credit for the “can reason about the CVPM paradigm lab” standard. If you don’t, I’ll give a bit of feedback to keep thinking and ask that you make a short screencast explaining your revisions, and this process could go on until we agree you’ve met mastery, or time runs out, and I have to report your grade.

I think this gives me a tool that will be manageable for students and teachers and will push us to get more out of our paradigm discussions, but I’d love your suggestions and feedback.

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