Re: multi-step reasoning

[Herbert H Gottlieb <herbgottlieb@JUNO.COM>]

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
>
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