Re: felt dismissed

[William Beaty <billb@ESKIMO.COM>]

On Sat, 8 Jun 2002, Chuck Britton wrote:

> If we keep a sense of humor, we MIGHT be able to even read (without
> gagging?) the occasional stuff that blames all college/university
> students misconceptions or lack of reasoning skills on their poor
> secondary education.

In a recent AJP there was yet another article on student understanding of
electricity.  The author found that after an intro physics class, students
still couldn't predict the brightness of light bulbs in a simple circuit.
Interviews found that the students assumed that copper was an insulator.
They assumed that it took a certain amount of e-field to "knock the
electrons off" the copper atoms.

I blame K-12 textbooks.     :)

Seriously, in this case I think the cause of the students' troubles is the
K-12 mental model of the atom, where each atom supposedly contains the
proper number of electrons and is always neutral.  A second cause is the
K-12 definition of the word "conductor", where "conductor" is any
substance which doesn't block the flow of electrons.

Until you get to the undergrad level,  nobody ever tells you that in some
materials the outer electrons have left their atoms.   Nobody ever tells
you that a "conductor" is not transparent to charge flow, but instead a
"conductor" simply contains mobile charges.



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