Over at Dynamics of Cats, chief herding theorist Steinn has a post on what we know about how to teach physics:
To teach physics well, you provide an intensive, mathematically rigorous in-sequence series of classes.
You need at least two different parallel classes per term, each class a prerequisite for the succeeding class and coordinated syllabii for parallel and successive classes, providing an initial short review of the previous material.
You also need a parallel sequence of coordinated mathematics classes, such that the mathematics needed for a physics class are taught before it is needed for the physics.
The base presentation can be done by lecture, there is a role for such.
you need labs, which are on the same material as the lectures, and which are in sequence with the lecture material, ie you do a lab on a topic right after it is presented in lecture;
further, you need weekly, or twice weekly, “tutorials”, where 2-5 students, no more, meet individually with faculty for an hour, or so, and discuss the material in depth.
“Wait a minute,” you say, “That sounds just like the traditional instruction format.” And you’re right. As Steinn notes later:
This works well.
It is how the physicists of the golden era learned, it is how many senior physicists of the current generation learned.
“But I thought research showed there are better ways to teach,” you say. This is also true. And that’s the conundrum of the post title.
On the one hand, the traditional method of physics education is expensive, labor-intensive, and wasteful. The vast majority of students taking introductory physics never take another class in the subject, in no small part because traditional instruction works to push them out. This is arguably most pronounced in physics, but it’s true of science as a whole.
At the same time, scientists trained in the traditional manner are undeniably effective, astonishingly so. On the list of great achievements of the human species, the Standard Model (incorporating special relativity, ordinary quantum mechanics, and QED) ranks pretty highly. So it’s not like we’ve obviously crippled our scientific endeavors through poor teaching.
The unanswerable question is what are we losing through the “sink or swim” approach? That is, we’ve shown that those who make it through can swim very well indeed, but we have no way of knowing what might have been done by people who said “To hell with this” after half a semester, and climbed out of the pool of potential scientists.
Would we have found a workable theory of quantum gravity by now if we hadn’t been so assiduously pushing people out of physics? There’s no way to know. Is the rise of curricula designed through physics education research producing a new generation of physicists who will be radically superior to past generations in some way? Maybe, maybe not.
What we have learned is that there are ways of teaching physics (and other sciences as well) that do more to engage students in the learning process. These methods have been shown to produce significant improvements over traditional instruction, at least in the area of conceptual learning, while not producing any significant decreases in student learning by more traditional measures (end-of-course exams, and the like).
This seems like a win-win situation, that ought to lead to dramatic improvements in… something. It’s not entirely clear what, though. And there’s the problem of what to do with all those students who are no longer being turned away– there obviously hasn’t been an increase in the number of available jobs for physics students, so what becomes of them? Are students who would have been great physicists under the traditional model being pushed out to make room for others? I doubt it. Are the people drawn in by new methods succeeding in traditional career tracks, or are they disproportionately moving into something else? It’s too soon to really say.
And, of course, as Steinn notes, none of this is any cheaper than the traditional method. Some PER-based methods are significantly more expensive, at least in the short term.
In the end, I tend to believe that having a broader and more diverse pool of students from which the next generation of physicists will be drawn can only be a good thing. I’ll freely admit, though, that I don’t have any concrete mechanism in mind when I say this, so it could just be my squishy liberal bias. If nothing else, though, doing a better job with the introductory classes will reduce the number of awkward conversations in which somebody I just met tells me how much they hated physics in school. That might not provide much concrete benefit for science or society, but it’d make me happier.