On 11/20/2003 06:43 AM, Matt Jusinski wrote:
>
> My task to to teach
> high school students about the everyday world.
....
> Presenting one notion of acceleration, the vector
> kind, for me, gives the biggest bang for the buck.
Yes, vector acceleration is an important goal of such
a course, and scalar acceleration is not the goal.
If the notion of scalar acceleration were not already
"out there" I would not have wanted to invent it, nor
wanted to introduce anything like it into the intro
physics curriculum.
But as the saying goes, learning proceeds from the
known to the unknown. Students necessarily arrive
with preconceived notions about heat, acceleration,
force, "conservation" of energy, and a thousand
other things. Dealing with this is a big part of
teaching and learning. For any given preconception:
-- One option is to use the preconception as a
foundation. That is, exploit it in a positive way
to get a head start in understanding the new notion.
-- In other cases where the preconception is just
something to be avoided, it still may be worthwhile
to mention it: the know-thine-enemy discussion.
Draw a line down the middle of the chalkboard and
put a few words (just a few words) about the old
concept on the left, and a few words about the new
concept on the right ... then draw a big slash
through the left.
The idea is to put things into *context*. Students
need to *reconcile* the new ideas with the old ideas
in their brain. Sometimes a connection is required,
and sometimes a disconnection is required, but in
either case this is hard for the student and we should
give them as much sympathy and as much help as we can.