OK, so maybe learning (and teaching) science is hard after all 4

One of my fellow Tangled Bank contributors, Mixing Memory. has an excellent essay on why it is so hard for students, or anyone for that matter, to accept evolution as valid. I saw so many parallels with teaching physics that I felt compelled to link to the post directly.

Physics teachers learn pretty quickly that one of our hardest jobs is to dislodge incorrect preconceptions from students’ minds. Until we prepare their minds to accept the correct explanations for natural events, no amount of lecturing, reading or testing will succeed in replacing the “wrong” ideas. Biology teachers have an even more difficult job conveying the validity of evolution, judging from the post.

Here’s an example from physics to demonstrate what I mean. Students by and large are ready to believe that heavier objects will fall faster than lighter objects. Sure, they may have learned in some earlier class that all objects will fall at the same rate, but if you catch them off guard, they will go with the heavy before lighter answer. Why? Because visual images are more effective than auditory or literary ones. Students have spent years seeing leaves, balloons, feathers floating to the ground, while heavier objects like balls, books and people just plummet downward. It takes more than one lesson to convince them that, in the absence of air resistance, all objects would have the same acceleration downward.

In other words, students, and I would assume most adults, are naturally Aristotelians. They are not Galileans. Aristotle taught that heavier objects fell faster than lighter ones, because of their nature. Galileo taught that nature is indiscriminant; gravity provides all objects with the same downward acceleration. It is only the effect of air resistance that obscures this fundamental truth.

Another example comes from earth science/astronomy. Students have a very fuzzy notion about what causes the seasons. Presumably, they are taught the reasons for the seasons in grade school and middle school, but without proper visual reinforcement, the explanations never really stick. Likewise, their ideas of why the moon has phases are muddled, because they confuse the dark side of the moon with the far side or because they never really understood the geometry of the sun-earth-moon system.

Now these are fairly small-scale concepts. They can be taught effectively with the proper visual aids, perhaps so that students can internalize the correct explanations. That internalization, however, is hard to achieve. Some students learn new material only long enough to pass the next chapter test, then lose it. Others may keep it forever. It’s hard to tell who it will be.

Evolution, on the other hand, is a complete theory, not a single, easily demonstrated situation. It not only flies in the face of so many students’ preconceptions, it also can assault their religious beliefs in a way that falling bodies and half-lit moons cannot. So, it’s no wonder that 53% of the US public are not willing to accept evolution as a valid explanation of the history of life on Earth. Even people who have been exposed to the theory in school may not have fully internalized it in the way scientists and science teachers have.

As with any difficult concept, learning and accepting evolution requires a willingness to discard, or at least subdue, pre-existing notions and beliefs. It also requires an openness to receive new explanations and information, whether they be easily visualized or not. That’s a major problem with teaching evolution (or the Big Bang). Most of the evidence cannot be made concrete. Teachers cannot “fast forward” the evolution of a reptile into a bird, or the early energetic universe into one filled with matter, in the same way we can model the phases of the moon with tennis balls and a flashlight. We can only appeal to students’ powers of logic and abstraction, and their willingness to accept what to some would be circumstantial evidence. Some may accept the new ideas. Some may consider them. Others may be incapable.

Einstein once said that common sense was the layer of prejudices laid down by the time a person was 17. If what Mixing Memory recounts is true for most people, then we science boosters have a hard row to sow.

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4 thoughts on “OK, so maybe learning (and teaching) science is hard after all

  1. Reply eljefe Mar 17,2006 11:34 am

    My host’s server is being really slow right now, so Mixing Memory is not the only one with problems.

    Chris: Teaching QM is fraught with difficulties. One is getting newbies to physics clued into the lingo (momentum, wavelength, etc.). Another major one is dislodging from students’ brains the unfortunate image perpetuated in lower school texts of tiny solid electrons orbiting a collection of tiny solid protons and neutrons. Some newer texts now describe the electrons’ positions as an “electron cloud,” which is closer to the truth, but not much better conceptually. Most people image atoms as tiny solar systems, an accurate description before Bohr’s and deBroglie’s days but not any more.

    Once we address those issues, we then have to explain that the QM model does not always follow Newtonian expectations. Some students get really upset at this notion, since we have spent so much time throughout the year stressing how widely useful Newton’s laws, etc., are. The concept of how measuring something changes the attributes of the something is disturbing to some, and misleading to others. That flick, What the (bleep) …, does not help matters. Students who have seen that piece of folderol get the idea that QM somehow corroborates religious/spiritual experiences or enables us to manipulate reality.

    I could go on, but I am considering a separate post (or page) regarding QM. Now that I have covered relativity, it’s time to give that other major 20th century branch of physics equal time.

  2. Reply Darcy Mar 16,2006 11:09 pm

    I was going to read the post you’ve linked to…but that server won’t allow me to access the page.

  3. Reply future geek Mar 17,2006 1:37 am

    I tried too. I also went to the tangled bank listing, and still couldn’t get on – either to the specific post or to mixingmemory.blogspot.com. Etrange.

  4. Reply Chris Mar 17,2006 2:18 am

    One of blogger’s “filers” is down, and any blog on that filer can’t be viewed currently. They say they’ll have the problem fixed soon.

    I’m actually interested in the intuitions that get in the way of learning modern physics. There’s actually a lot of research on folk physics that indicates that both children and adults reason about physical events in ways that are often wholly inconsistent with even basic Newtonian mechanics, much less more complex mathematical and physical facts (I can’t imagine how difficult it must be to teach QM).

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