Re: ENERGY WITH Q

[Ludwik Kowalski <kowalskiL@MAIL.MONTCLAIR.EDU>]

Referring to this:

> > As I indicated last night, the expression Q+W is likely to be
> > responsible for a misconception that work is a form of energy.

Robert Cohen wrote:

> If Q was interpreted to be a form of work instead of energy, would
> the expression Q+W still lead to the misconception that W is a form
> of energy (since the left-hand side is energy)?  I'm thinking of a
> similar conception regarding F=ma, i.e., that ma is a form of force.

In my sequence Q would be introduced in calorimetry. How
can it be "interpreted" as force*distance? Calorimetry leads
to a realization that mechanical energy is not really lost. At
this stage several kinds of mechanical energy are already
known to students and it is natural to associate Q with the
energy of heat. Joule discovered that generation of one calorie
of heat is always associated with 4.2 J of work done by a
dissipative force. In that way he recognized that heat is a
form of energy. Mechanical energy decreases and thermal
energy increases in a given system. Every form of energy
is associated with work but work is not energy. Work is the
concept used to define various kinds of energy. That is why
J is the unit of energy.

The beauty of physics is in its simplicity, we should try to
keep it as simple as possible in the first physics course.
Nuances and speculations could wait for more advanced
courses. A tendency to bring advanced ideas into the first
course is backfiring. Books become longer and longer
while students learn less and less. In this thread I would
like to draft an outline of energy topics for an introductory
physics course. It would be nice to have a minimal sequence,
and the associated vocabulary, which is considered to be
NOT WRONG by most phys-L-ers. That is why comments
from practitioners are so important to me. I already have
several pieces for the final draft to be posted here.
Ludwik Kowalski