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Re: energy in the tank




Is what we see real? Who knows? Are we seeing the real thing or only
some platonic shadow or is it all a dream? As far as I know, there is
no way to answer this question definitively. But we build models,
relentlessly. Models which, for the past few centuries, more or less,
have included concepts we label as energy, momentum, force, field,
mass, charge, and what have you.

Hugh, I agree with you. This physicist for one has long ago given
up trying to find "reality". Anyone who has studied QM would logically
come to this position.

My comments are meant to say that in many of our discussions we forget that
what we are talking about are _models_. In our thinking we sometimes
(often/usually) reify these concepts -- and what is worse and very
confusing to our students, we reify these concepts in our teaching
without prefacing what we are doing with a big reddish flag. We
and our students may come to think that "energy" for example is some sort
of "thing" inside the object under discussion.

The same is true for "momentum", "heat", "electric field and field lines",
"mass" or "charge" (although I think of mass & charge as being in a
different class -- these concepts weren't "invented" in the same way as
others were). We often end up in silly discussions and even come to
think of ourselves as being on the Enterprise and fighting with a "force
field gun"

In the teaching of physics language matters.

Jim Green
mailto:JMGreen@sisna.com
http://users.sisna.com/jmgreen