Re: The energy

[John Clement <clement@HAL-PC.ORG>]

> The orthodox view, which I hold to be correct: The energy is not
> substantial; it is not a real entity. The energy is an abstraction. The
> energy did not exist before it was invented. The energy is a state
> function, a quantity which may be calculated for any isolated physical
> system from the values of all the parameters that characterize its
> state.

Yes, but is this how energy should be taught?  The Modeling people firmly
come down against this view as one that should be taught in the intro.
course.  They model energy as something which can be transferred sort of
like a fluid.  Now this may be called heresy, but remember the essence of a
model is that it is a picture or concept that you can use to help understand
and explain.  Such a picture can and will then be modified as understanding
increases.  Their point of view is one which is based upon their
observations and testing of students.

Essentially the students need at first a concrete picture which helps them
to be able to correctly predict what happens in a variety of situations.  If
the student manages to arrive at the "theoretical level" of thinking, then
the orthodox view is natural and understandable.  As such, treating energy
like a substance allows them to understand that when it increases in one
place it must decrease by the same amount somewhere else.

I would propose that to a certain extent student understanding has to
proceed through various stages, and some stages will of necessity not be
consonant with current theory, but may actually be similar to earlier
historical understanding.  This is fairly similar to the Piagetian stage
theory which says that individuals progress through all of the lower stages
before they can arrive at the higher levels.  I would say that it is often
impossible to skip stages of physics understanding, just as it is impossible
to skip the Piagetian stages.

In addition, attempts to skip stages may block progress to the next
necessary stage, and will always prove to be fruitless.  An example from
Piaget is quite revealing.  Children always go through a stage where they
equate the amount of something with how it is spread out rather than the
number of items, before they comprehend that the amount depends on the
number of items.  They always go through the stage of thinking a heavier
ball pushes up water more than an identical size lighter ball when both
balls sink.  Some individuals never come to an understanding of this task.

I would propose the energy as a "fluid like substance" is a necessary bridge
to more abstract models of energy.  It is also probably the only way in
which students below the formal operational level can have any understanding
of energy.  The orthodox model requires the highest or "theoretical level"
(as proposed by Anton Lawson).  Since only 20% of HS graduates are at the
"formal operational" level and probably only 20% or fewer of college
graduates are at the "theoretical" level, the orthodox model is a tall order
to try to teach.

Incidentally our notions of reality are based on our senses which measure
certain things.  Would a being who has senses that directly measure energy
say that energy is a substance, and that our notions are wrong?

John M. Clement
Houston, TX