Re: Energy, etc

[Jim Green <JMGreen@SISNA.COM>]

At 01:35 PM 8/3/99 -0700, Dan wrote:
> Energy is as much a material entity as mass (as Einstein
> taught us) or particles (as quantum field theory teaches us).

I suppose that I should be a bit embarrassed that it has taken me all the
afternoon to respond to Dan, but Dan is a formidable thinker -- one does
not disregard him lightly!

And he is absolutely correct -- however he has missed the point:  BOTH
energy and mass are _properties_ of a system  -- just as "blue" might be --
or charge.  Neither "energy" nor "mass" nor "blue" nor "charge" move (or
flow) independently from the system -- The mass of a system is not the
system -- nor is the energy, nor blueness, nor charge.

It is simply incorrect to say that energy "flows" or  mass "flows" nor blue
"flows" nor, alas, charge "flows".  One sometimes gets away with mushy
language, but  often the language fails and so does the discussion or
pedagogy in the classroom.

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