Re: Physics & Chemistry

[palmer@sfu.ca (Leigh Palmer)]

>    I've come across a question that could use some unique insight to
> answer. If you take a spring and compress it, you've stored mechanical
> potential energy it. If you take the compressed spring and place it in an
> acid bath, what happens to the mechanical PE as the spring is desolved?

The only difference between the outcome of dissolving a compressed spring
and an uncompressed spring in acid, all other initial conditions being
identical, is that the dissolved compressed spring will produce a slightly
higher temperature in the final state of the system. Given the puny
mechanical equivalent of heat, I can't imagine that this is a matter for
practical calorimetry. A good exercise for a student would be to calculate
the likely temperature difference for a realistic numerical example. We
can do that in our heads; what we want to do is to teach our students to
do the same sort of thing. Yes, even the ones who aren't going to become
physicists should have the opportunity to try.

There is a philosophical point here. Why do I maintain that a temperature
difference will result in this case? The real reason is - faith! I believe
in the law of conservation of energy so much that I am confident of my
answer. I think that we should teach our students that, too. Yes,
especially the ones who are going to become physicists.

Physics is a cosmology, a belief system that helps us understand our
world. I believe it is the best one going, but I will never maintain it is
anything more than that, and our students should know that. If we don't
tell them then we are no more honest than the churches.

Leigh