Wednesday, December 28, 2016

Electron Clouds: A study in uncertainty

So it's pretty amazing to be preparing for next semester's course in cellular and molecular evolution. I told my dean earlier this year that I obsess about the way my students learn and experience science. Here it goes again. Even though I've taught this course or some variant of this course for more than 20 years I keep thinking about new angles. 

This year I want to go highly experimental in my approach. And by "experimental" I don't mean making students do experiments. Instead, I want students to experiment with new ways of looking at science. I want them to grapple with molecular structure and behavior. I want them to think about the way molecules and their workings affect living systems. And I want them to have fun--modeling molecules, modeling biological shapes and patterns, and modeling biological process. 

In preparing my first week's lectures for next semester I am confronted with an old friend that also presents an old problem. Wonderful water. We take it for granted. All living systems are made from it. We see it, touch it, experience it every day. And we are built from it. As scientists we take water and its characteristics for granted. Now, I could list out the properties and characteristics of water for my students. I could also, as I've done in previous years, explain the formation of the electron cloud around each water molecule, which contributes to its polarity. Of course, these features will be included in the first lectures of the semester.

But what about the phenomenon of the electron cloud itself? I have to ask, why do we tend to stop teaching about this phenomenon once we've finished teaching about water? Certainly electron clouds feature in every molecule large and small (consider proteins), and in multi-molecule systems like the phospholipid bilayer membrane. If we put aside the conventional "science" that students have had drilled into them since their days in junior high school, can we start to approach biology as a science of shape and conformation? Can we begin to explore biological interactions from the standpoint of perceivable form, working from there to stretch our perceptions past what is typically offered in textbooks? Can non-major undergraduates do conceptual work that's at the level of a speculative, highly exploratory doctorate? I think they can. 

I'm toying with the idea of having my students model a hypothetical electron cloud around a hypothetical atom or molecule. Usually for exercises like this I ask them to find Google images of the phenomenon they will model. Usually this works pretty well. But in previewing images of electron clouds I find that the number and variety of images are fairly limited. The last thing I want my students to do is to develop models that they copy from the typical organic chemistry schematics. More important than understanding orbital shells or p-levels, I want my students to think, rather deeply, about what an electron cloud is and how they might perceive it for themselves. 

A lesson like this might have more than one outcome. For example, electron clouds are all about uncertainty. We hypothesize about electron clouds based on statistical calculations--what is the chance that a certain electron will be in a particular position at a given time? Fairly complicated stuff. If we consider this at its deepest level we can conclude that matter itself is uncertain. Or at least, not "solid." Can we take this a step further and through it, suggest to students that perhaps their best laid plans about majors and careers are also a bit up in the air? As you can see, part of my ambitious goal is to use the models we build in science to help elucidate problems that are considered to be very much outside of science. 

It promises to be an interesting and engaging semester. Unfortunately, spring semester is always a bit short. And always there's a huge question to me whether my second-year undergraduates can really appreciate or even benefit from the thought I put into these questions about their learning. I guess I'll just keep at it and wait for their responses as the semester moves forward. 

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