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Re: Uncertainty Question



Hi Ken-
The question in my mind is not how the students reported the
uncertainty at the end of your canned problem, but how they reported the
uncertainty after being confronted with a data set at the end of the year.
Many of your students are accustomed to learning a topic long enough to
pass a test and then "scrubbing my mind" (an actual quote that I have run
into during 1:1 tutoring) in preparation for the next topic.

You wrote:
****************************************************************
I admit it, as part of my required curriculum I have to teach more about
uncetainties than I am confident about. The rules are inconsistent from
text to text and common sense does not always prevail. Is there a simple
guide book?

Here is my current question:
Measuring the density of a 3x5 card as an exercise in sig.fig.s and
uncertainty. Some groups used a micrometer to measure the thickness,
others made a stack of 50 and measured the group with a cm ruler. This
group measured the stack as 1.23 cm =/- .03 cm. We divide by 50 for the
stack. How do YOU report the uncertainty?

Ken Fox
********************************
Regards,
Jack

"I scored the next great triumph for science myself,
to wit, how the milk gets into the cow. Both of us
had marveled over that mystery a long time. We had
followed the cows around for years - that is, in the
daytime - but had never caught them drinking fluid of
that color."
Mark Twain, Extract from Eve's
Autobiography