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Re: [Phys-l] Student Misconceptions

On 09/28/2011 12:15 PM, andre adler wrote:
Is there a single volume a physics teacher can refer to that
contains/discusses common student misconceptions in physics, as
revealed by PER? I know that there are many articles documenting and
studying them, but they seemed to be scattered over the years and over
the journals. The desire is to use this as part of course preparation.

My advice is: Don't go there!

1) The fact is, students have more misconceptions than
anyone could possibly imagine ... but if you've made
it this far, you already know that.

2) There are so many misconceptions that it would be
impossible to list them all, let alone analyze them.

3) It is OK to talk about this-or-that misconception in
this forum, but talking about misconceptions in front
of students is at least as likely to reinforce the
misconception as to dispel it.

4) As a consequence of the above, the best policy, with
isolated exceptions, is to teach the correct concepts
and move on. "The light shines in the darkness, and
the darkness cannot overcome it."

Imagine a very narrow path through a vast swamp. You
want to stay on the path. If you pick a random point
in the swamp, there is a 99.99999% chance you don't want
to be in that place, or even talk about that place.

On rare occasions, as you lead students along the path,
you might want to point out something nasty that is
just next to the path, so they can recognize it and
avoid it ... but mostly it is easier to recognize the
path than to recognize the pitfalls. This is the Anna
Karenina principle: All happy students are alike, but
every unhappy student is unhappy in his own way, and
is going to find some weird misconception that you
never dreamed of.

5) The real cases worth worrying about are the ones that
are exceptionally prevalent and exceptionally pernicious.
The classic example concerns the washed-out bridge. It
is worth putting up a "Bridge Out" sign and maybe a
barrier and (better) detailed detour signs, because
people who haven't been warned are going to assume the
bridge is OK, with fatal consequences.

There are very few of these that show up in the intro
physics classroom. By way of contrast, in the research
lab you might have high-power invisible lasers, high
voltages, toxic chemicals, et cetera, and we would be
having a different conversation.

6) I'm not so much worried about the misconceptions that
the students bring to class as the misconceptions that
the teacher and the textbook author bring to class.

Having not taken my own advice, I made a modest list.
You've been warned:

7) Reading the PER literature is definitely a source of
misconceptions. I don't mean you will get a tidy list
of misconceptions, I mean you will suffer from more
misconceptions than you started with.

For example, the book
_Teaching Introductory Physics_
is – unintentionally – an extensive compendium of bad
pedagogy and wrong physics. For a detailed review,
including a list of some of the misconceptions propagated
and/or introduced by this book, see