Re: [Phys-l] Unit Conversions (was Mass and Energy)

[Hugh Haskell <hhaskell@mindspring.com>]

At 11:45  -0400 5/27/06, Richard Tarara wrote:
> I don't know about others here, but if I were to really believe in
> everything John Clement posts to this list then the logical conclusion is
> that people are just TOO STUPID to learn much of anything, much less
> Physics.  It would seem that there are just too many 'formalized'
> deficiencies out there to be overcome in any of our poor physics courses.
> I'm starting to doubt my own skills and abilities since certainly I
> couldn't have escaped all these learning disabilities.  I must not have
> really learned to read, write, and do arithmetic in K-8, nor learned
> Algebra, Geometry, and Trig  in HS.  I must not have understood anything
> useful about Chemistry and Physics in HS, and heaven only knows what was
> going on in College and Graduate School, because no one, to my knowledge,
> ever directly (or probably indirectly) addressed any of these problems John
> keeps listing.  They gave us material to read AND answer questions on
> (matched to our tested reading levels), had us memorize both the spelling
> and meanings of words--and forced us to write sentences (real sentences)
> using these words.  We had to memorize our math tables and then do all
> kinds of operations (no calculators to help us)--even doing square and cube
> roots by hand.  A few teachers may have even given us word problems to do!
> We worked through Algebra, Geometry, a real Trig course, and Analytical
> Geometry--Calculus was withheld until College.  In College I was surrounded
> by other students who seemed to have similar--if not superior--prior
> training.  I guess it was all just a sham!
I think there are a few things we all need to remember in connection 
with this discussion.

1) Our students are not blank slates, so that whatever we write on 
them will be automatically recorded and remembered. Quite the 
contrary; their slates are all filled with other material, some of it 
wrong, some irrelevant, some just confusing and incomplete. Before we 
can make much progress with our students, we need to recognize the 
need to erase some of the material that is cluttering up those 
slates, but also we need to remember that some of it is written in a 
form that is quite hard to remove.

2) We need to think back and recall what it was like when we didn't 
understand, and maybe sympathize with those students who are 
struggling through issues that we have long forgotten about.

3) It would be nice if we also remembered the times when various 
aspects of these concepts finally became clear to us. I suspect that 
for many of us it was only when we started teaching and had to deal 
with them on a daily basis that they finally became clear. The best 
way to learn a subject is to teach it.

4) Even if we didn't know about the stages of learning that John C. 
talks about when we were coming up, it doesn't mean that we weren't 
going through them. Some may have moved to one or another of them 
more quickly, or more slowly, or at a different time that we did, but 
one thing that can be stipulated, is that we *all* go through these 
stages, some more easilyu than others.

5) The progress through the stages has not much to do with 
intelligence (whatever that is). Some people get some of it quickly 
but never get other parts. Some who are very intelligent never get 
through them, or at least all of them.

6) There are huge cultural forces out there that push students away 
from even being interested in getting through these stages. It may be 
worse today than it was 50-100 years ago, but I doubt it. What has 
probably changed is the number of students who arrive at our doorstep 
(that is, the physics class). Those ill-prepared students of 
yesteryear would have been very much less likely to ever take 
physics, let alone any other science. In fact many of them would 
never even get to high school, let alone college. Today, they are 
breaking down the gates of not only high schools but also colleges.

I have all of my materials from my college courses (OK. I admit I am 
a pack-rat, and never throw anything away). Occasional I go back and 
look over some of it, especially if I am trying to solve a problem I 
have forgotten how to do. I look at the tests my physics profs gave 
in the 50s, and I don't see the questions to be any more probing or 
insightful than the ones I see on tests today. Many were "plug & 
chug," others were pure memory recall, and a few were well-crafted 
questions that probed my conceptual understanding. I don't think I 
did significantly better than on those than my students of today do.

Another thing that I think impacts on the ability of students to do 
things like unit conversions is the demise of the slide rule as an 
instructional tool, and the concomitant decline in the ability to do 
mental arithmetic. It isn't because students are not as intelligent 
as we were, but that they are not required to know how to do it. They 
all have sophisticated calculators, that they have been taught can do 
all their mathematical thinking for them, so they have no idea what a 
"reasonable" answer is to a numerical question. Hence, they don't 
recognize when they have multiplied by 1000 instead of dividing by 
1000 in a unit conversion, and do'[t see anything wrong with an 
answer that is off by a factor of 1,000,000 as a result. This isn't 
their fault; it is ours, the teachers, for not making sure they have 
to learn those skills.

In a certain sense, it is also the fault of society, which has pushed 
so much of what used to be the responsibility of parents onto the 
schools, so that the schools are required to spend so much time on 
social education that they have too little left over for the academic 
side of education. This has arisen largely (but not completely) 
because of some sea changes in our society over the past 50 years or 
so, many of them resulting from the upheavals of WWII. The nuclear 
family has pretty much disappeared from out society. In many 
households both parents work, or there is only one parent, who must 
work to support the family, leaving no one with the responsibility 
for teaching "life skills" to their children. Hence they get pushed 
off onto the schools, which are already overburdened with other tasks.

Some of these tasks are, IMO, appropriate for the schools to teach, 
but some are probably better done in the home. But in any event, 
there are only so many hours in the school day, and as the burdens 
assigned to the schools increase, something has to give. Our society 
seems to have decreed that academic skills are less important than 
social ones, even though it is probably true that the schools are a 
poor place to teach many of the social skills they are now expected 
to provide our children with.

So don't blame the students for not being able to do what you think 
they ought to be able to do easily. Blame a system that doesn't give 
them the foundation to enable them to take on what you are offering. 
Blame a society that is generating the need for skills that didn't 
even exist 60 years ago (computer programming, e.g.). Blame a society 
that refuses to put the emphasis on education and to pay for an 
educational system that will serve the needs of all students, and 
give them the opportunity to develop the skills needed to succeed in 
your classes. Blame, if you will, a society that doesn't weed out the 
students who don't have the intelligence to take on the 
higher-skilled intellectual tasks before they get to the point where 
they find they need them (you can blame them for this, if you choose, 
but I won't).

Hugh
--

Hugh Haskell
<mailto:haskell@ncssm.edu>
<mailto:hhaskell@mindspring.com>

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