Re: Calculators during exams

[sample@lyon.edu (John D. Sample)]

At 8:41 PM on 2/23/97, <phys-l@mailer.uwf.edu> wrote:

> With regard to the issue raised by Pang-Chieh Chou:
>
> For a number of years it has been my policy not to permit the use of
> calculators
> during exams. (This is for the calculus-based introductory course.) I
> prefer to
> give non-numerical exams for two reasons:
>
> (i) They are easier to grade. When students plug in numbers at the
> beginning of
> a problem (as is their wont), it rapidly becomes difficult to follow where
> they're going. If they work with a small number of symbols, it's easier
> to keep
> track of what the student is doing.
>
> (ii) I don't have to worry about students whose calculator batteries fail in
> mid-exam. (That was certainly one advantage of slide rules!)
>
> My attitude is that numbers are something that gets plugged in at the end
> of a
> problem, not at the beginning. By leaving the numbers off the exams, I am
> essentially making the problems shorter!
>
>
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++
>
> Roger A. Freedman
> Dept. of Physics and College of Creative Studies
> University of California, Santa Barbara

I agree with your attitude, and wish more textbook problems were
derivations and of the type you describe (hint, hint, 10th ed?).  I've
actually calculated the percentage of these type problems in the Haliday &
Resnick texts of today and 20 odd years ago.  Roughly 20% of the problems
in the old text are nonnumerical, but this has fallen to about 5% in the
newest edition.  (I suspect most texts have evolved in this direction as
well.)  This trend seems exactly the opposite of what should have occured
as calculators made numerical problems less valuable as exercises...at
least with a slide rule the student must calculate the order of magnitude
by hand.

By the way, a trick to penalize students for plugging numbers early is to
require them to do the calculation twice and compare answers.  Plugging
early requires the student to start the second time from scratch, while
waiting to the last step before plugging makes the second part trivial.

(I should have said I'm rewarding students for doing the right thing rather
than penalizing them for doing the wrong thing...I'm sure there must be a
rule against the latter;)

Chip

J. D. Sample                          (501) 698-4625
Math-Physics Dept                     sample@lyon.edu
Lyon College
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