2 Mar
2013
2 Mar
'13
8:11 p.m.
N0body H0me wrote:
I can tell you, that as late as 1979, basic slide-rule
was taught (using the
aforementioned six-foot-rule) as part of "Introduction to Scientific Method"
which all freshmen had to take at my high school. The rationale was that it
taught students to effectively read scales, and to interpolate values between
tick marks. It also gave them a sense of what a log scale was, and how values
were represented thereon.
I really can't remember taking a formal class on how to use
a slid rule. I purchased mine in 1956 when calculators
probably did not exist. It is probably still around somewhere.
One aspect that seems absolutely critical, at least in my opinion,
is that when a slide rule is being used, it forces the ability to at
least estimate the answer since the slide rule only provides the
first 3 digits in the answer, NOT where the decimal point is
located.
After using the slide rule for a while, I noticed that everyone who
used this calculation aid developed the ability to estimate the
answer, almost without thinking about how it was done. let alone
why it was essential. As a consequence, it became possible, or
so it seemed, to pull answers out of a hat that were often quite
accurate, often within about 20%. Many individuals could look
at a problem and provide what seemed like a guess even though
it was just providing an estimate of a slide rule calculation for which,
of course, an estimated answer was essential in the first place.
Using a calculator robs the individual of the ability to estimate an
answer since the decimal point is provided along with the mandatory
digits. Using a calculator also seems to encourage an individual to
fail to understand that the input data usually has far too little accuracy
to justify more than about two digits of accuracy in the final answer.
When values accurate to 8 digits always appear as the result, it
becomes very easy to forget that the initial data was often accurate
to less than 1%. Further, even when the initial data is very accurate,
the equations used to provide a solution can often be VERY non-linear.
It is possible to produce variations in the result of more than 50%
due to variations in the input of much less than 1%, especially when
non-linear differential equations are being used. Of course, doing
those kind of calculations even with a calculator would take months
or years as opposed to what a computer can do. But the same sort
of concept applies as to the accuracy of the result with a calculator.
Jerome Fine