Re: [Phys-l] season's greetings

[Rick Tarara <rtarara@saintmarys.edu>]

As has been said on this forum before--for science/engineering students, all 
of this is fine, but if you are working with a general-education group or a 
high-school group and you main concern is getting accross that all 
measurements are of finite precision and AT BEST carry a +/- 1 unit 
uncertainty in the last recorded digit AND that when you combine 
measurements to calculate another quantity (say density from measurement of 
dimensions and mass) then one needs to be careful about implying that one's 
calculation may suggest a greater precision or confidence than is warranted, 
then the relatively simple concept of significant digits and the rules for 
combining such mathematically seems (IMO) sufficient for such an audience. 
Later in the course we will do a lab where we get  concerned about doing a 
more sophisticated error analysis, but for the audience and the level, sig 
figs are really not so terrible, despite JDs (and other's) aversion to such.

So, not to open this argument again, the bottom line is that if sig figs 
serve your purpose (and your purpose is NOT to produce research level 
scientists) then I think ignoring JD on this point is OK!  ;-)


Rick (who also ignores JG and uses 'heat' as a noun!)

***************************
Richard W. Tarara
Professor of Physics
Saint Mary's College
Notre Dame, IN
rtarara@saintmarys.edu
******************************
Free Physics Software
PC & Mac
www.saintmarys.edu/~rtarara/software.html
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----- Original Message ----- 
From: "John Denker" <jsd@av8n.com>

>    /It's that time of year again:  the start of school.   Chapter 1 of
>    the textbook goes on and on about significant digits.  A few
>    students sit there, fidgeting, wondering whether the teacher is
>    really crazy enough to believe this stuff.  The more they think
>    about it, the less sense it makes.  But// only a few of them bother
>    to think about it at all; most of them learned long ago that
>    thinking about classwork is a lose/lose proposition./
>
>
> Maybe I'm overly optimistic, but I think we can do better than that.  We
> can start by eradicating the sigfig nonsense.   I recently updated my
> web page on the subject.