Comments on: Don't Know What a Slide Rule is For

By: George Olson

George Olson — Wed, 27 Jun 2012 16:19:03 +0000

The last time i used a slide rule was in June 1972. I used a 6 inch RICOH log log the I purchase din Japan in July 1968. The occasion was the descent of a QUANTAS 707 V-Jet into Brisbane on a non-stop flight from Honolulu. I had eyeballed the angle of descent observing the nose down tilt of the cabin and estimated altitude of 42,000 plus feet, speed of 550 mph in throttled back glide.
The leveling off would occur at about 3,000 feet and somewhere between the estimations and the slide rule I came out dead on. The flaps started to extend and the engines increased in power as the sweep second hand on my wristwatch which Mom had used as a WAC Sargent in WW2 ticked past the last 5 seconds of my prediction.

By: Dr. Gene Nelson

Dr. Gene Nelson — Sun, 24 Jun 2012 06:29:45 +0000

I appreciate the above mention of Clifford Stoll, Ph.D. He and I attended SUNY Buffalo as graduate students in different depatments. I recall talking with Cliff while he ran the planetarium and related equipment. Cliff later wrote he very engrossing nonfiction book, “The Cuckoo’s Egg.” http://en.wikipedia.org/wiki/The_Cuckoo's_Egg_(book)

By: Eldora Brighton

Eldora Brighton — Thu, 05 Apr 2012 05:33:37 +0000

Enormously educational thanks, I do believe your visitors will likely want further blog posts like this maintain the excellent effort.

By: adamson

adamson — Thu, 05 Jan 2012 18:47:53 +0000

I once had one in hand when I was in high school, at that time It was great to have such a tool in hand, I completely forgot how to use it. How sorry I am.

By: Pierre Sydler

Pierre Sydler — Fri, 16 Sep 2011 06:53:07 +0000

On July 20 th 2011, Mr Frank Van Haste wrote :
« …slide rule does NOT tel you where to put the decimal point. »
A quite simple method exists !
For a multiplication, using the slide rule’s right side, the number of digits of the product is equal to the sum of the number of digits of the factors.
8 400 x 12.5 gives a number of digits of the product of 4 + 2 = 6 digits, reading the slide rule, the answer is 105 000.
For a multiplication, using the slide rule’s left side, the number of digits of the product is equal to the sum of the number of digits of the factors minus one digit.
12.5 x 0.45 give a number of digits of the product of 2 + 0 – 1 = 1 digit, reading the slide rule, the answer is 5.625.
For a division, using the slide rule’s right side, the number of digits of the quotient is equal to the difference between the number of digits of the dividend and the divisor.
2600 / 0.0042 gives a number of digits of the quotient of 4 – (-2) = 6 digits, reading the slide rule, the answer is around 619000.
For a division, using the slide rule’s left side, the number of digits of the quotient is equal to the difference between the number of digits of the dividend and the divisor plus one digit.
625 / 2.4 gives a number of digits of the quotient of 3 – 1 + 1 = 3 digits, reading the slide rule, the answer is around 260.

By: Mike

Mike — Mon, 12 Sep 2011 18:39:51 +0000

Here’s video with the slide rule explanation:

http://www.youtube.com/watch?v=waiprjueVpQ

By: Frank Van Haste

Frank Van Haste — Wed, 20 Jul 2011 15:34:23 +0000

The great thing about a slide rule is that it does NOT tell you where to put the decimal point. This forces you to understand the problem at hand well enough to be clear on the order of magnitude of the answer. The digital calculator, in contrast, gives a precise answer which too many students happily accept, regardless of the accuracy of the inputs.

With a slide rule, you can’t mistake precision for accuracy – two very different things!

By: bankky

bankky — Wed, 17 Nov 2010 08:46:24 +0000

I used the slide rule during my high school years. I have to admit it was a very useful tool that allowed me to ace a lot of exams.

By: chosenkingreyes

chosenkingreyes — Sun, 07 Feb 2010 17:46:38 +0000

I used the slide rule during my high school years. I have to admit it was a very useful tool that allowed me to ace a lot of exams.

By: HP-25C « HP calculators and space exploration

HP-25C « HP calculators and space exploration — Sat, 05 Sep 2009 21:56:34 +0000

[...] Here’s another blog comment of a former NASA engineer I found while roaming for [...]