[TheForge] Slide rules (was: Excessive scaling?)

[Bruce Freeman]

I was a graduate student and  teaching assistant in Chem 101 when
calculators were just "replacing" slide rules.  (When I was in college,
I couldn't AFFORD a calculator!  I used a slide rule throughout.)

In chemistry, one common problem is to deduce the empirical (simplest
possible) formula of a chemical compound from the elemental analysis. 
You start with a composition:  percent carbon, percent hydrogen, percent
nitrogen, etc.  You then assume some arbitrary total sample weight
(e.g., 100g), calculate the grams of each element, and divide each by
its respective atomic mass to give a number count of the atoms (moles,
gram-atoms).   

At THAT point the objective is to determine the SIMPLEST formula.  So
you whip out your slide rule and take ratios.  You see that the 2 on one
scale is almost over the 3 on the other and conclude - 2 atoms of the
first and 3 atoms of the second.

But these hot-shot yahoos instead would whip out their eight-place
calculators and conclude that there were 19 atoms of the first and 31
atoms of the second.  Or 192 atoms of the first and 308 of the second!

They got SO pissed off when we marked them wrong...

Bruce
NJ

>>> David.Hufford at EKU.EDU 12/12/2006 7:31 AM >>>
The slide rule ... what an ingenious implement.  I used one all
through
college.  Wish I still had it.  Not long ago I saw one in an 'antique'
shop, along side an IBM PCJr.
David Hufford
Richmond KY