Several times we have lamented that the word "flow" is apt to be construed
as flow of something material or of some sort of fluid. Brian McInnes said
this quite well when he stated... "I believe its use carries the pedagogical
danger that our students, especially at an introductory level, move simply
and quickly from the word flow to the misconception that the property
flowing is a fluid. In the everyday world of these students things that
flow are fluids and fluids are stuff."
I wonder if this is too pessimistic. Certainly some students get this
goofed up, but the physics definition of flow is not the only one that does
not involve fluid. There are a several definitions of flow in the
Merriam-Webster Dictionary that do not involve fluid or transfer of matter.
The examples given are not physics examples. One definition is...
to derive from a source... "the wealth that flows from trade"
Another is...
to proceed smoothly and readily... "conversation flowed easily"
For sure, students are not always aware of various definitions of common
words. But the examples above demonstrate that we physicists are not the
only ones using flow in a way that does not involve fluids. Students
certainly hear and read about the types of flow described above and I don't
think it bothers them. Therefore I would say that an educated public, or at
least a public that wants to be educated, shouldn't have problems once we
explain that flow of energy does not necessarily involve the flow of some
sort of fluid.
Of course, one problem with the physics of thermal energy is that sometimes
it does involve fluid. The thermal energy made available in my furnace gets
to my bedroom because I have water flowing in pipes between my furnace and
my bedroom. But I repeat that a public wanting to be educated ought to be
able to figure this out. If students have problems with this, I don't think
it's a problem with words, I think it's a problem with desire.
Michael D. Edmiston, Ph.D. Phone/voice-mail: 419-358-3270
Professor of Chemistry & Physics FAX: 419-358-3323
Chairman, Science Department E-Mail edmiston@bluffton.edu
Bluffton College
280 West College Avenue
Bluffton, OH 45817