As we near the end of the semester, Physics 131 is once again finishing up with a unit on the statistical interpretation of entropy (not a typical topic for an introductory algebra-based course). This unit gets started with two labs: one systematically playing the famous Monty Hall problem and a second models the free expansion/compression of a gas using coins. While I do not have strong evidence for this belief, I feel that these two labs are the strongest two labs we do all semester. Students seem to really engage with these two labs and the act of doing the experiments really seems to add to student understanding in ways I do not see with other labs in the course. Even our much celebrated lab investigating the bio-mechanical ground-reaction forces of the human jump doesn’t seem to engage our students as much. Why? What is the “magic sauce” of these two labs? How can we modify the other labs of the course to achieve these same ends?
In the Physics 131 course, the lab is fully integrated with the rest of the curriculum. The 4-credit course meets three days per week for 75min per session without a set lab day. All meetings take place in the same TBL room. When the material we are exploring lends itself well to laboratory exercises, we do labs. Some labs, like Monty Hall, are a single period, while most extend over several class periods. Students turn in “lab reports” as teams and all team members receive the same grade. Traditional lab reports are difficult to write in teams leading students to “divide and conquer” with no student gaining full mastery. Therefore, our lab reports are, instead, a series of questions for the students to answer in a sentence-or-two. Ideally, the team members craft these sentences collaboratively. While we are expressly NOT emphasizing formal scientific writing, I feel that this goal is probably better taught within the students’ home disciplines. Let biology courses teach writing so that students learn the culture of writing that is actually appropriate to their discipline.
This semester, P131 had 5 labs:
- A lab using ioLabs to investigate graphical representations of motion by actually creating the motion.
- A lab where students developed a spreadsheet to numerically integrate the motion of an object being launched to the side and acting under Newton’s Laws.
- A lab where students jump on a force plate to investigate the biomechanical forces involved in the human jump (NOT trivial!)
- The Monty Hall Lab
- A lab where students flip coins to explore the ideas of free-compression/expansion and the impact of increasing the number of atoms.
The Monty Hall, Free-Compression, and Numerical Integration labs are obviously the “best” in terms of student engagement and student take-away as informally measured by other references to the lab later in the course. Formal measurements should definitely be done. However, I find that early in development when something does not work for students, it is fairly obvious! What is their “magic sauce?” A few common themes come to mind.
First for the better labs, the equipment needs for all of these labs are negligible. The equipment does not get in the way. Students, therefore, have the mental space to focus on the physics and not get hung up on why their equipment is not working.
The other two labs are predominately graded on getting “correct” answers. For example, in the jump lab, students are graded for correctly identifying 11 different stages of the human jump with correct free-body diagrams. Some students find more than 11, all correct, or a different 11 through different classification. They then tend to get focused on getting MY 11 stages.In the graph lab, if their graph is not a perfect replica of my computer generated model, they get stressed and will focus on getting a perfect match instead of the more important general trends.
This fixation on the “correct” answer is, I think, partially, this is how the rubric is structured and partially the training of students: when graded on getting the correct answer, they focus on getting that answer. Failure now has consequences which is detrimental to learning. All people must fail as part of the learning process. Establishing a safe environment for failure is the reason why my in-class problems are not graded for accuracy. I want students to take risks and fail in situations where there are no consequences.
Another feature of graded labs with lots of questions is that students spend class time making sure that the minor questions are answered to get every last point. A better use of time would be to focus on the more challenging problems and fill in the smaller questions later. While I try to control the pace and in-class emphasis on the more challenging elements through my slides, the battle is definitely uphill.
Given that I feel obligated to have some graded lab as we are a laboratory course, how to achieve an environment where failure is acceptable and where students stay focused on the challenging parts in class and save the smaller elements for homework? I feel that the entropy labs provide a good model. These labs are focused on challenging preconceptions. Students explicitly write about what they think will happen, and then try to reconcile what the data are telling them.
Perhaps all the labs could be constructed in this way? For the jump lab for example, we currently spend time on prediction, but what if we spent MORE time on it? What if students, after seeing some problems which give a few hints, were required to construct a detailed explanation of their prediction and why? The lab would then be essentially three questions: prediction, data, and reconciliation. Perhaps I would also give one-or-two other small problems at the end to connect the numbers to their everyday world, but prediction, data, reconciliation would be the focus. We would still do all the same problems in class, but they would not be graded. However, students would be required to understand them to complete the reconciliation part of the lab.
This model has, I think some benefits. Students would now have an explicit opportunity to challenge the incorrect preconceptions that many students have entering Physics-I. Each lab, would be focused on specific known misconceptions such as “forces cause motion.” They would be required to write about physics in words, which is an important skill to me. There would be less focus on correct. In fact, investigating and owning your failures would be the emphasis. Finally, the reconciliation process could be easily scaffolded: guided questions in the first labs with fewer questions as the semester progresses.
This model would also result in more smaller labs which is very much in line with the best practices of modern education theory.
The genesis of this idea came out of informal discussions between Paul Bourgeois and I today and I wanted to get them down before I forgot especially as it may be awhile before I teach this course again.