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[Phys-L] physics force ... as opposed to agency, intent, causation, et cetera



On 08/28/2016 01:30 PM, LaMontagne, Bob wrote:

What you definitely in my
opinion do NOT want is another student on the end - but what you want
instead is the agent of the force that is pulling the student along to be
inanimate (just as the agent of the force that keeps the box from falling
through the table is inanimate).

That's tricky. Let's be careful.

Students arrive with an entrenched understanding of "force" in
terms of agency, intent, and causation: The bandit "forced" the
lady to hand over her purse. There is no third law here; there
is no equal and opposite "force".

This is the vernacular notion of "force". It is not wrong; it's
just different from the physics /force/. Context matters.

We must also distinguish the pedagogical starting point from the
desired ending point. It's not possible to teach everything at
once, but we have to start somewhere.

Eventually students must understand that the physics /force/ is
independent of any notion of animate agency, intent, or causation.

We don't necessarily need to make a big fuss about it on Day One,
but still we have to be careful. It is possible to duck the
issue temporarily by putting the physics /force/ in the same
location as the intent and causation, e.g. by having the student
pull himself along ... but we need to move beyond that, the
sooner the better.

That is to say: Sooner rather than later, you *should* want to
have the animate agent, intent, and causation to be at the far
end of the rope, well separated from the physics /force/ you
are asking about.

With rare exceptions, I don't like to talk about misconceptions,
but the distinction between physics /force/ and vernacular
"force" isn't intrinsically a misconception. Both notions are
correct, each in its own context. A misconception arises only
when one of the concepts is taken out of context.

If you want your students to get good FCI scores, you need to
confront this. One of the ugly things about the FCI is that
some questions paint a picture where it would make sense to
use the vernacular notion of "force", and then penalize the
student for doing so.

You have to confront it; you can't just let it slide for very
long. The non-physics notions will never die out, because they
are too well entrenched in the non-physics world where people
spend most of their lives. The winning strategy is to /delineate/
the physics notions from the non-physics notions, so everybody
(including students) can tell which concept goes with which
context.