On 07/17/2017 03:27 PM, Tim Daneliuk wrote:
On 07/17/2017 11:18 AM, Richard Lahrson wrote:
Hi,
So like my 8x10 2-D camera with a 360mm
lens has big bellows sag, and for a long time
I couldn't figure a simple solution. Then I
tried a slide rule: just right! It adjusts for length
and the clear plastic gives extra support that moves,
plus it anchors on the front and back wooden shelves
of the camera.
I think I learned how to add and subtract with it but
that's about it. Maybe a portrait prop today.
Rich
As an engineer and computer dork of many years, it is my considered opinion
that one of the worst things we ever did was remove slide rules from the
classroom. Yes, assuming precise input, calculators provide far more
precise answers. But slide rules taught people to "visualize" arithmetic,
conceptualize things like logarithms, estimate things with reasonable
accuracy, and - most of all - grasp orders of magnitude.
I recall some years ago, I was teaching graduate computer science wherein
I announced "No partial credit" (along with "No late work", "No grading on
a curve", and "Spelling and grammar matter"). A few weeks later, someone
came to me to dispute a grade. They'd gotten the significant digits
correct (coefficient), but were off by 2 orders of magnitude in the exponent.
"But I'm close", he wailed, I just got the last bit wrong. "You were
off by 100x", says me, "How'd you feel if your boss moved your paycheck
amount two decimal places to the left?" Blank stare. THAT is what happens
when people can punch in numbers but don't really understand how numbers work.
If it were up to me, calculators would be illegal in High School and
slide rules would be a required skill to graduate.
P.S. I have all my old slide rules from my wooden Versalog to the later
plastic models. Along the way, I've also collected a few more for fun.
In fairness, I've also reacquired (and made work) every model of
HP calculator I ever owned. Wait ... I'm starting to see a pattern here.
The past isn't what it used to be ...
