Re: teaching electric circuits

["William J. Larson" <bill_larson@CSI.COM>]

Thank you for saying something that I strongly believe but was
afraid of saying on this list.

==>use of these physically "naive" assumptions gives the students
==>an opportunity to practice physical concepts. After relationships
==>between electric field, potential and current are understood I
==>complete the physical aspects that are initially neglected.
Actually after presenting the naive concepts, I often decide its
more productive to move on to the next topic, so that at least
they will have seen the next topic.

Flame shields on full power! Warp 9! The Death Star (AKA Leigh)
just materialized out of hyperspace. Scotty, Get me out of here! Now!

Cheers,
Bill Larson
Geneva, Switzerland

----- Original Message -----
From: Savinainen Antti <antti.savinainen@KUOPIO.FI>
To: <PHYS-L@lists.nau.edu>
Sent: 2000 May 06 9:40 AM
Subject: teaching electric circuits


> Hi,
>
> I guess that people are getting bored with this topic but there is
something I'd like to say.
> Thanks for Leigh and others from illuminating discussions. Physical
aspects have been thoroughly illuminated. But I'd like to address some
didactic views. There is quite a lot of evidence that students do not reach
conceptual understanding on electric circuits even though they might be able
to solve problems using Kirchhoff's laws. For instance, Professor Eric Mazur
gives one convincing example from Harvard in his Peer Instruction Manual.
Professor Arnold B. Arons discusses in depth difficulties and remedies in
his marvelous book Teaching Introductory Physics. Just for the record: these
professors are "real" physicists.
> My point is that without explicit teaching of conceptual analysis students
simply will not learn it (of course there are always some exceptions). If
you don't believe this try out some exercises from Peer Instruction Manual!
I have found out, like some research papers suggest, that use of these
physically "naive" assumptions gives the students an opportunity to practice
physical concepts. After relationships between electric field, potential and
current are understood I complete the physical aspects that are initially
neglected. I always make the students to determine how resistance depends on
current in case of a resistor and a light bulb. In the end (hopefully) the
students can do reasoning recognizing how different assumptions affect the
conclusion. Final exams involve reasoning and calculations. Nobody gets an A
just by knowing how to solve equations.
> I agree with Leigh that we must try to teach physics as a description of
the real world. But I have noticed that to achieve this "naive" assumptions
may be needed in the beginning. Well, I'm willing to consider using
resistors as an example instead of ligh bulbs; it would make the assumptions
less naive.
> Regards,
>
> Antti Savinainen
> Physics teacher
> Finland