Are We Afraid to Teach Truly Exciting Science?

I’ve heard it said that the answer to any headline asking a yes-or-no question is “no”, and this post is probably no different. Let’s try a different question: why in general do introductory physics classes, whether in high school or college, neglect physics since about 1900? Even if relativity (first proposed in 1905) and quantum mechanics (usually covering only Bohr’s 1913 version) are discussed, it’s in a perfunctory way at the end of the second term, which isn’t required for all students. Many colleges offer a third term that is only taken by physics majors which does cover modern physics, but if a first-year student is on the fence about majoring in physics, that’s too late.

I’m sure there are exceptions, but I doubt that most people become interested in physics for the type of material that’s taught in introductory physics classes. They may find certain topics intriguing, but the level of the material doesn’t lead to very deep investigations. (Can you imagine teaching astronomy and stopping in 1900? No galaxies, no stellar evolution, no cosmology, no Kuiper belt, etc. Can you imagine teaching chemistry or biology and stopping in 1900?) Despite the argument that you need a solid grounding in Newtonian mechanics before moving on, you don’t even get that: Newtonian mechanics proper isn’t usually taught until the second or third year, after students have gotten a lot of math under their belts. In my experience, many people who become fascinated by physics do so after hearing about black holes or superconductors or string theory as children, by watching Nova or Carl Sagan or Neil deGrasse Tyson on TV. That’s more or less my own story, and I don’t think I’m unique.

So why do we hold out on the good stuff? Why don’t our introductory books and curricula cover more modern physics, the topics that excite and inspire interest? I confess, I fall into that category myself: I’ve tried to incorporate exciting topics into my introductory physics classes, but I’ve hesitated to be radical. My cowardice is part of the problem, so don’t think I’m standing superior to my colleagues: I am not. I write to indict myself as well as others, in hopes that we can change this in the future.

Let me be provocative and provide some possible explanations for why we teachers of physics hold out on the good stuff from our students.

  1. As I mentioned before, a common reason given is that students need to learn all about classical Newtonian physics before they can be exposed to quantum physics and relativity. Though it’s true that quantum physics builds from classical physics, it’s also true that the concepts are linked. Why not teach atomic structure earlier, after energy has been introduced?
  2. Maybe modern physics is too hard for introductory physics students. I don’t buy that, since we lower the mathematical sophistication of every topic we teach the first time around. Our students usually can’t solve the second-order differential equations that underly Newtonian physics, but that doesn’t stop us from teaching the concepts and some of the simpler problems. Simple doesn’t mean unimportant!
  3. There aren’t enough jobs in pure physics to employ everyone interested, so we need to discourage all but the most dedicated students from going into the field. If you think that’s a good reason, leave and never darken my towels again.
  4. Most people taking introductory physics in college are biologists and students going into medicine, dentistry, or veterinary studies, and maybe they don’t need to know anything but the most basic physics to do their work. That’s another option I find offensive: that’s like saying I shouldn’t write about Feynman diagrams or cosmology or pretty much anything on this blog, because most of this stuff isn’t necessary for your daily lives. Live in ignorance, people! I’m shutting down right now.
    Seriously, though: if our intent is to only teach the bare minimum needed for a particular person’s studies, we’re not doing well at that either. We don’t teach much if any biological physics (much less its more complex cousin biophysics), and even topics that could be connected to biology aren’t. That’s partly parochialism: I admit I don’t know much biology and where it connects to my field, so I’d need to learn new stuff, but if that’s an excuse, it’s a lousy one. (I’m not proposing turning introductory physics into a biophysics class, either: just maybe we need to incorporate some into the curriculum.)
  5. Maybe we’re just too lazy to change the curriculum, since it’s built on a pedagogy that’s been around for over 100 years, and uses textbooks based on ones written in the 1950s. But that’s just crazy talk.

Cue a spate of people in the comments telling me that they do teach modern stuff, and they don’t fall under any of these criticisms. I know many people do better than I at this, but let’s face it: as a community, we’re not doing well. Physics education research has done great things for improving the classroom side of things, but has hardly touched the curriculum itself, which is bloated, unwieldy, and still fails to convey physics as a living, active field of study. (Don’t even get me started on Khan Academy, which just gives students what they think they want, and ignores all the research on teaching.) Textbooks are too expensive and largely interchangeable with one or two exceptions, aimed mainly at students who had really great high school educations. It’s great and necessary to find new ways to teach, but if you’re just teaching the same stuff, you’ve only gone halfway.

I have no immediate solution, other than to reexamine the curriculum and see what we can do to improve it. It’s worth doing, though, and until we do it, we will continue to lose bright students who think physics is boring, pointless, and irrelevant in the modern world.

6 responses to “Are We Afraid to Teach Truly Exciting Science?”

  1. Curriculum inertia often gets blamed for a lack of more challenging or modern concepts in science classrooms. Perhaps that was to blame in the past but that’s not really how it works today, and the news is good.

    Today more than half the states have adopted the National Science Education Standards This is a definite shift from the days of “No Child Left Behind” that allowed states to define their own standards, in deference to states rights. The result of that was wildly varying curricula, especially in science and especially especially in areas that made bureaucrats squirm such as teaching evolution. Even the planetary sciences have their squirm moments when talking about planet formation in schools.

    This doesn’t just benefit students who move around, it benefits the students that stay put as well. Textbook content has been largely driven in the past by states with their own standards who also buy the same textbook across the whole state. The 35 states that have adopted this new national core curriculum now have the influence to hopefully prevent science that has been twisted to meet some agenda from making it into the books.

    These standards are coming out of the National Research Council, an organization that knows how to bring smart people together to get something done. This is the same body that produces the decadal surveys in astronomy, astrophysics, planetary science, biologic sciences, etc. which drive the next 10 years of research in those fields.

    Still in the end, the curricula is just a framework and it’s up to parents and teachers to challenge students.

    1. When I say “curriculum”, I’m not referring to educational standards: I’m referring to the textbooks used in classrooms. Most teachers don’t deviate from that material, or at least not very far. I would venture to say that the specific form textbooks take is not dictated by national standards, but by inertia and copying. (Not meaning plagiarism or anything else illegal or intellectually dishonest, but copying the form, order of topics, and so forth.) Nearly all textbooks, even the better examples, cover the same topics in the same order to more or less the same depth, and you can’t blame educational standards for that.

  2. This is part of why I fell out of physics. I wanted to study astrophysics and I got an old man shooting across the stage on a cart with a fire extinguisher attached. Then in lab I got to take little cars and attach them to springs. I wasn’t seeing links to big ideas – maybe if I saw connections to how the universe works – even rudimentary ‘once we know this we can move on to…’ comments, I might have been more inspired and stuck with it. But by semester 3 of calc and physics and nothing that linked up to my career goals, i found a new career.

  3. While we simplify mechanics and do the easy problems at the 100 level, it is still taught as a quantative science. There’s very little QM that can be done with first year calculus, so when it’s touched on, it is done in a qualitative fashion. And I think that teachers are rightly leery of teaching a series of facts to be learned rather than tools that can be used to solve problems. \

    1. Yes and no – it’s true that a lot of quantitative problems are too difficult, but there are still some that can be done. After all, even the second-year “modern physics” courses have to mix qualitative and quantitative material because solving the full Schrodinger equation is too advanced until third or fourth year.

  4. […] I guess there’s something in the water, or perhaps it’s the end of the term, but at least two people independently wrote excellent pieces on how teaching sciences isn’t doing all it should…and how we can do better. (My own piece is here.) […]

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