Re: "all accelerations are 9.8m/s^2"

[John Denker <jsd@MONMOUTH.COM>]

At 08:28 PM 1/25/01 -0600, John M. Clement wrote:
> g is then stated as being 9.8N/kg at the surface of the earth, not 9.8m/s^2

At 11:36 PM 1/25/01 -0500, Hugh Haskell wrote:
> > >every year a certain fraction of my students complete the course thinking
> > >that "all accelerations are 9.8 m/s^2! It really makes for some
> > >interesting answers to problems.

And in reply I wrote:
> > Innnnnteresting.  That throws quite a dramatic light on the situation.
> ....
> > it seems the students in question are missing the crucial
> > distinction between
> >    a) there exists some acceleration equal to 9.8m/s^2
> >    b) each and every acceleration is equal to 9.8m/s^2
> >
> > Formally this is called First Order Logic.
> >    http://www.bestweb.net/~sowa/misc/mathw.htm#Predicate


Then at 06:43 AM 1/26/01 -0600, John M. Clement wrote:
> Teaching logic may not work.  There is evidence that shows that courses in
> logic do not actually improve the ability of students to think.

Well, Hugh's anecdote suggests that taking the approach "g is not an
acceleration" leaves a certain fraction of the students unable to think
clearly about First Order Logic.

> My data shows that math does not seem to raise
> student thinking skills much, but physics "can" be effective.

I'm sorry, I find it highly implausible that speaking about N/kg in place
of m/s^2 will improve anyone's ability in First Order Logic.  It is even
more implausible that avoiding a direct discussion of logic will be helpful.

If you really have data that addresses these points (not anecdotes, but
real data with double-blinding and other controls) please provide a more
specific reference.

> Significantly raising average student thinking skills takes about 2 years
> of work ....  A mini course is very unlikely to be effective, but a
> concerted year long effort may have some benefit.

Ah, that's a different statement.  I'm not sure totally I agree, but let's
stipulate that as a hypothesis and discuss the consequences.

If a mini-course that takes the logical bull by the horns is "very
unlikely" to be effective, sidestepping the issue and introducing N/kg
versus m/s^2 seems very very very very unlikely to improve students'
abilities in First Order Logic.

So if we take an approach that is so ultra-unlikely to succeed, we should
not be surprised if
> > > every year a certain fraction of ... students complete the course
> > > thinking that "all accelerations are 9.8 m/s^2!

It doesn't matter whether this is classified as a logic problem or a
physics problem -- the point is that if students are leaving the
educational system with deficiencies of this magnitude, it's a problem for
everybody.