Re: Extra Credit (was Where Have All the Boys Gone?)

[Hugh Haskell <hhaskell@MINDSPRING.COM>]

Joel Rauber wrote:

> Derivations are a bit of a hot-button issue for me.  I believe that one
> shouldn't have students do tasks for which they won't be made possibly
> responsible for later.  Derivations are a good example of this (whether
> done
> as part of lectures or in some sort of active engagement method), I don't
> think one should deal with derivations unless students will be responsible
> for them, or that kind of reasoning skill, in some fashion.

I'm not a stuffy about derivations for the following reasons: first,
I remember how much trouble I had with them as a student, usually
ending up just memorizing them. That served nothing. Second, except
for simple algebraic manipulation of a single equation. Most students
have no experience in derivations, so it doesn't make sense to have
them memorize a munch of them at the expense of some real learning.
Third, I do them in class, even though I don't test on them, for two
reasons: 1--to see what kind of reasoning and thinking goes into a
derivation, and more importantly, to show them that when you know the
answer you are heading for, it's easier to get there, and if you
don't know the answer, then "organized fooling around" is an
acceptable approach; and 2--the students need to know that, even if
they don't understand exactly where an equation comes from, it is
important to see that it *doesn't* come from some writing on a stone
tablet. Physics lies on a logical foundation that is held together
with mathematics and it is important for students to know that, even
if they can't do the work themselves. If they go on to study physics
in depth, there is time enough for them to come to the derivations
later.

Unless the mathematics is beyond what they have studied, and I cannot
find a quick and dirty derivation, I never give the students an
equation without a derivation, unless it is a fundamental equation
whose basis is empirical and it has no derivation. In that case, I
make it abundantly clear that this *is* one of those things that is
just true and we have to accept the world the way it is, and be
thankful that we can describe it mathematically even if there is no
deriving the equation.

Hugh
--

Hugh Haskell
<mailto://hhaskell@mindspring.com>

Let's face it. People use a Mac because they want to, Windows because they
have to..
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