Re: multi-step reasoning

[Chris Horton <chrisahorton2@HOTMAIL.COM>]

If no work is done then t can't change - something which is extrinsic to the
equation.  There is the rub.  You have to specify how this could happen.

So if t doubles what happens to P and V?  Answer me that!  Hah!

8-)




> From: Herbert H Gottlieb <herbgottlieb@JUNO.COM>
> Reply-To: "phys-l@lists.nau.edu: Forum for Physics Educators"
> <PHYS-L@lists.nau.edu>
> To: PHYS-L@lists.nau.edu
> Subject: Re: multi-step reasoning
> Date: Wed, 21 Aug 2002 01:28:32 -0700
>
> Chris...
>
> I was quite interested in your PV question below and
> wondered if I was able to arrive at the correct answer myself..
> I reasoned that if V is doubled, (other things being equal)
> then P would immediately be reduced to half its value and the
> nRt would remain the same.
>
> Is my reasoning correct???
>
> Herb
>
> On Wed, 21 Aug 2002 00:39:41 -0300 Chris Horton
> <chrisahorton2@HOTMAIL.COM> writes:
> > One place where students are called on to think beyond a simple
> > relationship
> > is with the ideal gas law
> >
> > PV = nRt
> >
> > I don't have my sources available but I was reading recently how
> > nearly all
> > students - including some graduate students in chemistry - faced
> > with a
> > question like "what will happen if V is doubled?" will either ignore
> > one of
> > the three variables, or apply them one step at a time in a
> > sequential
> > reaoning process, usually imagining a two-step process over time.
> >
> > What is going on is that they are trying to arrive at an answer
> > algorithmically, when the algorithms won't give them a meaningful
> > answer.
> > What is needed is to have the students learn to habitually create
> > models of
> > situations, and consider carefully what all the constraints are on
> > their
> > models, before trying to crank out an answer.
> >
> > Students can learn this habit but they won't as a rule come up with
> > it
> > themselves.  Students want the easy way and that ain't it! But once
> > they
> > learn it they will find it is not just a more powerful way, it's
> > also more
> > satisfying.
> >
> > 8-)
> >
> > Chris Horton
> >
> > _________________________________________________________________
> > Chat with friends online, try MSN Messenger:
> > http://messenger.msn.com
> >




_________________________________________________________________
Send and receive Hotmail on your mobile device: http://mobile.msn.com