Re: Nitpicking: gravity is not a force???

[Mervin Koehlinger <tchkoehlimw@crf.cuis.edu>]

On Fri, 7 Aug 1998, William Beaty wrote:

> The above misconception could be changed thus:
>
>    THERE IS ONLY ONE KIND OF FORCE.  HOWEVER, FORCES ARISE WHEN
>    VARIOUS FIELDS INTERACT WITH MATERIAL PARTICLES, AND THERE ARE FOUR 
>    KNOWN FIELDS: ELECTROMAGNETISM, WEAK, STRONG, GRAVITY
>
> Anyway, I think we would do some good if we warned students that gravity
> is not a force, e-field is not a force, there is no "force of magnetism," 
> etc.  Try to undo the damage that the "four known forces" concept has
> done.  Make everyone feel uncomfortable when they accidentally say that
> "electric force" fills the dielectric of a charged(!) capacitor, or that
> the "force of gravity" fills the region surrounding the earth. 

I agree wholeheartedly with you.  I studiously avoid the use of the phrase
"force of gravity" in my physics classes for the exact reason that you
state: it leads students to think that it is always the same magnitude,
even though they can calculate that it isn't.  It is very confusing to
them.  I use the term "gravitational attraction of the earth" in its
place.  "Gravitational field" would be appropriate also, once we cover the
field concept.

Mervin

Mervin Koehlinger
Physics Instructor
Concordia Lutheran High School
Fort Wayne, Indiana