Date: Fri Oct 19 11:32:52 2007

Author: Curry, Robert T

Subject: Re: Neat Web Video


Paul, I agree wholeheartedly. One of the most memorable and valuable
demos from my student days involved heat conduction. Two equal-sized
rectangles (about 4"x8"x1/8") - one of aluminum, one of asbestos board -
are placed on rings stands above burners. Four matches are placed on
the two rectangles so that one match is directly above the flame, and
one is on the far end. We then were required to vote on the order in
which the matches would ignite then the burners were lit. I still
remember how surprised I was when the one on the asbestos above the
burner lit first. It showed me clearly where I misunderstood the
consequences of conductivity.
Bob Curry

I'm told that students should really have to guess the outcome of a
demonstration before they see it. That might help them to remember
if they were right or wrong. Neglecting to ask them to think before
then see a demo is surely a mistake. But it's not the only mistake.
When we try too hard to entertain ourselves with some novel result or
special case, it can simply be confusing for the student. It often
was for me.