Re: [Phys-l] "Flow"

["John Clement" <clement@hal-pc.org>]

Unfortunately, by not using the word transferred or flow, a large number of
students will be left behind.  While the very top students might understand
the concept that when momentum in one object is increased it decreases
correspondingly in another object or collection of objects, the lower
students will simply not grasp this idea.

Remember you are trying to make models which students understand.  Or rather
you are trying to get the students to construct mental models which make
sense and allow them to predict results.  All mental models rely heavily on
analogy and spring from already existing ideas.  There is plenty of research
which shows that analogy does improve student learning.

One of the ways to approach this is to say that a mental model of momentum
is that it is something which is in an object, and can be transferred to
other objects, but does not go away.  You can even say that this is just a
mental model or analogy if you will.  But in the end all of physics is a set
of mental models which use mathematics to make predictions.  BTW the very
successful Modeling program explicitly uses the mental model that energy is
something that can be transferred, so some of the PER groups have bought
into the idea of doing this.

If you rely on etymology and the thesaurus to provide answers to this
question, then students will have extreme difficulty.  You really have to
start from where the students are not where you think they should be.  This
is pure Arons.

John M. Clement
Houston, TX

> Thank you, bc-- This I understand
>
> At 12:46 AM 5/20/2006, you wrote:
> > I answered the question for myself by using google (etymonline.com).
> >  From the similarity in the roots and the words themselves, I think the
> > idea of flow should be eschewed by instructors of beginners, except for
> > (with) real (as opposed to  imaginary) fluids, e.g. water, gasses, ions,
> > etc.
>
> You seem to agree with Larry here, but I wonder if it should not be
> eschewed by "instructors" everywhere.  Medical language seems to be
> very precise perhaps for a reason.  Here on this list our discussions
> sometimes seem to get bollixed up because the language  looses precision.
>
>
> > p.s.  momentum is transferred from one object to another by work (+ & -)
> > during a collision?
>
> Or as a result of any kind of interaction?  As in the Joule case?
>
> Would you consider not using the term "transferred" as well?  If it
> is a property of a system, its magnitude can be changed, but not
> moved independently.
>
> Thank you for your helpful reply.
>
> Jim
>
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