Re: Significant figures - a Modest Proposal
- From: Glenn Knapp <kahuna@VCN.COM>
- Date: Thu, 26 Aug 1999 22:21:44 -0600
>I think that learning the concepts of physics is sufficiently
difficult
>for students without clouding their minds with somewhat
arbitrary
>procedures which will be of no long term use to them. The
concepts of
>precision and accuracy, and of uncertainty and error, do need to
be
>taught, but they can be deferred until the students have learned
some
>science to which to apply them. Let's get rid of this
traditional
>dinosaur and see if it helps students learn.
>
>Leigh
I don't know. . . . is it that hard to teach significant
figures? I spend about 20 minutes teaching my students the rules
for significant figures, use them in all example work, and require them
to do so as well. Within a week, they use the rules quite
easily. I think its important in science to use significant
figures. We make measurements which are limited in precision.
This in turn limits the precision of the answer.
If you don't require the use of significant figures, then you'll get
decimals with eight places. Either that or you limit them to three
or four numbers -- but this is arbitrary and there is no good reason to
do it. Especially when dealing with data taken during labs.
I teach high school physics and chemistry and physics for the local
community college. The first chemistry meeting we were reviewing
powers of ten and scientific notation -- I hadn't gotten to significant
figures yet. One of the students who had been in my high school
physics class two years earlier was very uncomfortable with the
work -- "What about significant
figures!" She was used to doing them and did not like to see a
bunch of arbitrary digits that weren't justified (at least to her
thinking) up there on the chalk board.
I can't debate the absolute relevance of significant figures --
whether in fact the rules do all that they are supposed to do -- but they
are pretty standard in most texts in both chemistry and physics.
I think they are worth doing.
Glenn
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