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Re: [Phys-l] teaching energy



Regarding the two papers that Joel Rauber has called our attention to:

In (2) "Teaching About Energy" by Robin Millar
http://www.york.ac.uk/depts/educ/ResearchPaperSeries/Paper%2011%20Teachi
ng%20about%20energy.pdf
we find the following definition of a "system":
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A 'system' just means a group of objects that can be treated as a
single unit.
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In (1) "Making Work Work" by Greg Swackheimer
http://modeling.asu.edu/modeling/MakingWorkWork.pdf
a very different definition of the word "system" is being used:
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In many introductory courses, energy is characterized as thermal
energy, kinetic energy, gravitational
energy, electrical energy, elastic energy, etc. In the face of these
commonly used names, it is
important for students to understand that energy does not come in
different forms. The distinctive
names arise because of the different systems in which energy is stored,
not because there are
different forms of energy. Energy is just energy. We will attribute, for
example, thermal energy to
the "thermal" system in an object, that is, to all its atomic scale
oscillator systems, translational
kinetic energy to the center-of-mass system of an object, elastic energy
to the structural system,
gravitational energy to the gravitational field, and electrical energy
to the electric field.
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In (1), an object consists of systems, whereas in (2), a system consists
of objects. I find the definition in (2) to be closer to the
thermodynamics concept of a system and that the definition in (1)
amounts to a workaround to avoid associating the different ways in which
energy manifests itself with different "forms" of energy. It would seem
that the definition in (1) would cause unnecessary confusion in the
study of thermodynamics.