Current Reading

This blog is primarily for me to blog my responses to books that I'm reading. Sometimes I blog about other stuff too, though.

I'm currently reading Edward Teller's Memoirs.

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Tuesday, November 8, 2016

More thoughts on _They're Not Dumb, They're Different_: The pedagogy side

The best critique of physical science education offered by the outside observers in this book is that we focus mostly on technique over concepts and the big picture.  We focus on technique over concepts because we want to equip students with the tools to get meaningful, testable answers to questions, not just general ideas.  The ability to precisely and accurately calculate something, even something simple and boring, means that you can engage with the material world in an objective manner that is not accessible with only qualitative, conceptual, "What does it really mean?" types of explanations and analyses.  That is the power of what we offer.  It's what makes progress in our disciplines possible, it's what makes us employable, it's what advances society's technological and material comfort, and it's what gives us access to truths of some sort.  Whether you value the advancement of society on an intellectual level or a material level, whether you value the advancement of the pure or applied sides of the discipline, and whether you value the students' intellectual development or career preparation, the case for focusing so much attention on technique and problem-solving is quite strong.  I make no apology for it.

Where I think the outside observers have a point is that we can do more to motivate technique, more to provide context.  We can do this both in the structure of the material, the textbooks, the syllabi, etc., and in the structure of an individual class session via sign-posting of what we're doing, interspersing more context-rich examples with technique, etc.  In the past 20 years I think there's been more (justifiably!) raised awareness of these points in science teaching, and greater emphasis on context, motivation, and organization of class time is all to the better.

But there are limits to how far we can go.  These limits are best understood by contrasting two very different types of science courses: General Education science for students not majoring in science or engineering, and the more technically-focused classes for students in science and engineering.  In a GE course, one can spend a quarter or semester building up, say, a basic understanding of what energy is, and the basic concept of how a nuclear power plant works, how a solar cell works, etc.  In doing so, one can help the student become an informed citizen and appreciate the basic points of major societal issues and why science matters.

HOWEVER....

When you look at what it takes to prepare a person to actually make a tangible contribution to these issues, what it takes to prepare a person to make progress in solar cell technology, or to help design a safer nuclear power plant, it is painfully necessary to step back from context and focus on technique.  For years.  Once we've established that solar panels work by photons getting absorbed and raising electrons to higher levels, if you ask "How does that photon get absorbed? How can we improve the efficiency of that process?" we need to talk about matrix elements in quantum mechanics.  There's no getting around that.  If you ask "How can we make this material more cheaply?" we need to talk about a host of issues in chemistry and materials science and manufacturing, all of them highly technical.  To go beyond "Oh, we need to make these parts less expensively" to "So, we'll have to deposit thin films of materials made from exotic elements, and do so in vacuum chambers..." now we're talking about highly technical matters.  The goal of a science class for a science major is to help a person along that long journey.  We can do some sign-posting and motivating at the beginning, but at some point you have to accept a long slog through basic optical physics in order to get at what's going on inside the solar cell on a level sufficient to improve it, and basic diffusion and transport theory in order to understand the nuclear reactor on a level deep enough to actually improve it.

As far as the competitive nature of science classes, I agree  that competition can be off-putting.  I didn't like taking freshman chemistry with grade-obsessed pre-meds asking questions about curves and critiquing each and every aspect of the grading scale.  (I'm typing this from a cafe in a medical school, incidentally, as I wait for an appointment with a specialist.)  But what I don't think students get is that when you look at the trajectory of physics problems, and the decreasing math level, in many cases "grading on a curve" is not about putting students in a Darwinian competition but about lowering our own expectations to the point where "enough" students can actually pass.

Also, lab work has always been hands-on and involved groups.  Never, ever forget that.  LAB WORK IS HANDS-ON!!!  Critics of science education love to miss that point.

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