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The conceptual change process (long)

On Sat, 14 Feb 1998, Bob Sciamanda wrote:

I'm sorry, but I really think this objection is silly. In almost 40 years
of teaching physics I have never known this phraseology to be
mis-interpreted, nor did any danger of this happening ever even occur to me
until I first saw it exposed on this list. A language which can peaceably
live with "lb." as the abbreviation for "pound" has long since learned that
there are more serious battles to wage than the proper choice of a harmless
sound.

I'm an electrical engineer. As a physics stuent, I was your customer.
Please regard my stuff about "capacitors store charge" as being the
complaints of an angry customer.

If capacitors store charge, then when I "charge" a capacitor, the charge
going into one wire must be MORE than the charge going out the other,
right? Otherwise charge would not build up inside. This is shown on most
schematics: one wire is grounded, the other wire is used to deliver and
extract charge. But I don't really understand why the grounded wire is
needed. And, when I "discharge" the capacitor with a resistor, the charge
leaves the capacitor and goes... where? Into the resistor? Into the
ground? I'm confused.

....

New concepts which replace old concepts hurt our self-image. I've seen
this over and over in myself, and I believe that it is the main reason
that students have such trouble aquiring new physics concepts. If I had a
misconception, not only must I erase the old misconception and learn the
new concept, but I must also face the fact that I had been WRONG, often
embarassingly, publicly wrong. It's a serious blow to my vanity. Totally
new information is much easier to communicate. But when the new
information must expunge a previous misconception, I find that I will
fight the new concept "to the death", and only accept it when I realize
that I've been "defeated"; that my previous concept was actually a
dangerous misconception I'd earlier aquired. Then I get mad, and track
down the source of the earlier misconception. I notice that this is
similar to that "emotional stages of trauma" thing, DENIAL, ANGER,
BARGAINING, ACCEPTANCE. Below I adjust those to match physics education,
using myself as an example:

The four stages of conceptual change:

1. That new concept is WRONG!

2. That new concept might be theoretically correct, but it's a
distorted way of viewing things. It's not really useful, and any
effects on physics teaching are vanishingly trivial.

3. That new concept is important, its effects are stronger and
more pervasive than I had ever imagined. Everyone should be taught
this new concept.

4. Where did my previous misconception come from? WHO TAUGHT IT TO
ME??!!! I'll get them for that!

5. I never said the new concept was wrong. I noticed it years before
anyone else did.

Currently I try hard to jump directly to #3, without also sliding into #4
and #5. Not easy. The narcissism of a modern human is no trivial
opponent. It is particularly important to avoid #5, since it contains
an automatic denial that misconceptions exist, and it totally erases any
opportunities for learning the lessons of history. If I slip into #5, I
will repeat the whole list again and again each time I'm forced to give up
another misconception.

I see that nearly everyone else also follows the above list, or a
variation of it. The "bernoulli" thing seems to be reaching #3 on a
global scale.


All this stuff contains a valuable lesson, in that it rubs OUR noses in
the same sort of thing that students go through. I find it very difficult
to take a superior attitude regarding student misconceptions, or even to
regard myself as an "educator". I'm no educator, I'm just another lowly
student, and I have just as many misconceptions as anyone else. My goal is
to find out why we students have such difficulties in learning new stuff.
If I considered myself an educator, my goal would read more like "I teach
and teach, but these darned students just don't get it, why is this?" The
former goal requires simply glancing within myself to see the source of
the problem. The latter requires mounting a gigantic research campaign to
extract the true source of the problem from "those darned students."

Regarding capacitors,

I identified a misconception within myself: CAPACITORS STORE CHARGE.

I gradually noticed more and more ways that this misconception damaged
my abilities as an electrical engineer, and also noticed more and more
ways that I gained new skills once I'd defeated the misconception.

Then I kept my ears open to see if this is a common misconception, or
was it just a personal quirk. Ah, when I talk with fellow engineers, I
find that they all have the misconception too.

Next I start looking for where my misconception came from. AHA!
Electronics class. Physics class. It was specifically taught to me,
and many textbooks contain the phrase "capacitors store charge." True,
physics texts also teach that plates are oppositely charged. But this
does not defeat the CAPACITORS STORE CHARGE misconception. Electronics
texts don't say much about what really happens, they follow the lead of
physics texts and teach that CAPACITORS STORE CHARGE, but without
adding any other details.

So I type the whole story into my webpage. Every so often I get
messages from physics students and electronics people saying things
like "After thirty years in electronics I FINALLY FINALLY understand
capacitors! THANK YOU!"

And when Ludwik starts the "Misconceptions list", I type the
CAPACITORS STORE CHARGE misconception into it.

I now expect to fight a big battle as everyone else progresses through #1
to #5. But at least the PHYS-L list gives me a channel to whine about it!
:)

((((((((((((((((((((( ( ( ( ( (O) ) ) ) ) )))))))))))))))))))))
William J. Beaty SCIENCE HOBBYIST website
billb@eskimo.com www.eskimo.com/~billb
EE/programmer/sci-exhibits science projects, tesla, weird science
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