Re: borrowing from tomorrow

[kfox@shhs1.smoky.org (Ken Fox)]

> The law of universal gravitation is usually introduced when students are
> > already familiar with the concept of inertial mass and with the mass
> unit.  The basic
> law of electrostatics, on the other hand, is usually introduced in the first
> unit (chapter) of electricity. The concept of charge, the unit of charge, and
> the force law must be learned at the same time. This creates many conceptual
> difficulties.

Because the law of gravitation has already been introduced and "understood"
and because so many have had some  experience with static interactions, I
have not experienced the conceptual difficulties that you(Ludwik) allude
to. As your later post suggests, it might be interesting to try teaching
currents first, though I don't find, in my teaching, compelling reasons to
shift from the traditional order.

On the other hand, if one were to teach currents first, where would one
come up with a concept of what was in motion and why? I like developing the
idea of field and potential first.

Ken Fox
Smoky Hill High School
16100 Smoky Hill Rd
Aurora,CO.80015
303-693-1700
kfox@shhs1.smoky.org
http://stega.smoky.org/~kfox/Physics.html