Matter & Interactions II, Week 12

We’re hanging out in chapter 19 looking at the properties of capacitors in circuits.

In response to my (chemist) department chair’s accusation that I’m not rigorous enough in my teaching of “the scientific method” as it’s practiced in chemistry, I just had “the talk” about “THE” scientific method with the class and about how it doesn’t exist. I will never forget Dave McComas (IBEX) telling the audience at an invited session I organized at AAPT in Ontario (CA) that we MUST stop presenting “the scientific method” as it is too frequently presented in the textbooks because it simply does not reflect how science works. No one hypothesizes a scientific discovery. Once a prediction is made and experimentally (or observationally in the case of astronomy) verified, that’s not a prediction because the outcome is expected. Even if the prediction isn’t verified, one of the required known possible outcomes is that the prediction is wrong. There’s nothing surprising here. True discoveries happen when we find something we had no reason to expect to be there in the first place. The Higgs boson? Not a discovery, because it was predicted forty years or so ago and we only recently had the technology to test for its presence. I don’t think anyone honestly expected it to not be found, but I think many theoretical particle physicists (not so) secretly hoped it wouldn’t be found because then we would have actually learned something new (namely that the standard model has problems).

The “scientific method” simply doesn’t exist as a finite numbered sequence of steps whose ordering is the same from discipline to discipline. Textbooks need to stop presenting that way. Scientific methodology is more akin to a carousel upon which astronomers, chemists, physicists, geologists, or biologists (and all the others I didn’t specify) jump at different places. Observational astronomers simply don’t begin by “forming an hypothesis” as too many overly simplistic sources may indicate. Practitioners in different disciplines begin the scientific process at different places by the very nature of their disciplines and I don’t think there’s a way to overcome that.

Rather than a rote sequence of steps, scientific methodology should focus on validity through testability and falsifiability. I know there are some people who think that falsifiability has problems, and I acknowledge them. However, within the context of introductory science courses, testability and falsifiability together form a more accurate framework for how science actually works. This is the approach I have been taking for over a decade in my introductory astronomy course. It is not within my purview to decide what is and is not appropriate for other disciplines, like chemistry. My chemist colleagues can present scientific methodology as they see fit. I ask for the same respect in doing so within my disciplines (physics and astronomy).

I now consider “the scientific method” to have been adequately “covered” in my calculus-based physics course.

Feedback welcome as always.


Learning Critical Thinking Through Astronomy, Week 7

The week began with my expectation that students had watched a YouTube clip showing an excerpt from Carl Sagan’s COSMOS series in which Sagan explains Eratosthenes’ work with shadows. Students don’t realize it yet, but this topic is the culmination of all of the previous activities. It’s the reason for the critical thinking activities. It’s the reason for the shadow activities. It’s the reason for everything they’ve done so far in the course, all embodied in Activit0206.

The first class day was spend working on some WebAssign content that provides formative assessment related to the first three shadow activities. I use WebAssign content in this course as as rough indicator of engagement. Two sections show nearly one hundred class participation, but the third section shows only about twenty-two percent participation. I said enough about my problems with motivating students in the last post so I’ll dispense with that here.

One daytime section and the evening section began Activity0206 on the second class day; each of these sections only meets twice each week. The other daytime section had to wait till its third class day to begin (today, actually), but that’s good because that was the only day that was sunny.

For this activity, students compared four models (flat Earth, nearby Sun; flat Earth, faraway Sun; curved Earth, nearby Sun; and curved Earth, faraway Sun) to actual data (most of which is simulated, but it’s still accurate) and eliminate the models that don’t support their observations. We used the whiteboards for flat Earth, yoga balls for curved Earths, and Nerf darts with suction cups for sticks. This activity is supposed to be the most scientific thing students have done up to this point and hopefully they will now see many connections to previous activities that built up the process they’re expected to go through here. Of course, many will still not be able to see all the pieces, but that’s to be expected. Most eventually will.

Part of the activity must be done outside with the best faraway light source we have available. However, the week was cloudy with the exception of today (Friday) so the other two sections has to improvise inside the classroom. That’s okay, and we made do with a “distant” light source in a far corner of the room and the various test Earth’s in the diagonally opposite corner.

It’s interesting that this has historically been one of the more difficult activities, at least according to students. This semester, I was pleasantly surprised to hear some students in one section (the section that seems the least engaged to me) to say they thought this was the best activitity so far becuase it was something they could immediately relate to. That puzzles me a bit, but I’ll take it!

As always questions, comments, and constructive feedback are welcome.

Learning Critical Thinking Through Astronomy, Week 4

This week, we wrapped up the first series of seven activities. Students were expected to have completed Activity0105 outside of classs last week (even though I know many did not) and Activity0103 outside of class this week. Class time was devoted to questions raised by those two activities (if there were any, and there were essentially none) and Activity0104 and Activity0106.

Activity 4 focuses on frameworks, aka theories, and how they are created by people. In the spirit of Feynman, the idea is to watch some “natural process” play out and try to write down the “rules” that govern the observed process. I use a simple dice game (I don’t want to divulge too much here in case students find this page) to model a “natural process” and students have to watch as I play the role of Nature, remembering that Nature doesn’t directly answer questions we pose, and try to predict what will hap”open when this “natural process” occurs again. They generate their list of rules, their frameworks, and then use them to discuss how frameworks generate questions and predictions.

Why the word “framework?” I decided years ago to tackle the problematic word “theory” by simply eliminating it entirely from the lexicon. We really don’t need it, because it’s inevitably going to be misused either accidentally by those who don’t know better and intentionally by those who do. Either way, it’s a problematic word and I feel that either “model” or “framework” would be a better replacement. I opted for the latter, mostly I’ve yet to see a way it can be misused in the way that “theory” is frequently misused.

Activity 6 focuses on scientific validity and the concepts of testability and falsifiability. I understand there is some discussion about whether or not science needs falsifiability, but I am currently not swayed by any of this. I may address this in a future revision of this activity. Students almost always confuse “false” and “falsifiable” and this semester was no exception. I had to address it with a mini-lecture.

I’ve also made use of several videos by Veritasium (aka Derek Muller) and his excellent YouTube channel. His videos on guessing numbers, wrong research, truth by repitition, why anecdotes trump evidence, and good vs. bad predictions are especially relevant.

Now, if I have done everything correctly (and there’s no guarantee that I have) and if students have properly engaged, at this point in the course students have a good foundation for what science is and how it really works as opposed to the traditional rigidly numbered steps called “THE scientific  method.” It’s sad that students are still subjected to this rigid set of steps that, unfortunately, no two authors agree on. Specifically, there’s no agreement on how many steps there are and there’s no agreement on the order of the steps. Let’s just stop presenting scientific reasoning that way and present it as a continual process that can start anywhere (but must be ultimately traceable back to some natural phenomenon…or so I think…I may be wrong).

As usual, students are still using the word “proof” in much of their conversation and I’ve been unusually silent about this so far this semester. However, I will have to address it, but I will do so as an outcome of assessments next week.

Speaking of next week, we’ll begin the next chapter and series of activities, the theme for which is observation.

I welcome feedback, questions, and constructive criticism.