### Author Topic: Slide rules  (Read 2396 times)

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#### Canis Dirus Leidy

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##### Re: Slide rules
« Reply #50 on: November 08, 2019, 05:27:41 pm »
A some useless numbers. The approximate amount of time required to complete (include the writing on paper) these operations using an ordinary slide rule.
• Multiplication of any two numbers: 10 seconds.
• Division of any two numbers: 8-10 seconds.
• Squaring and cubing: 3-4 seconds.
• Calculating of square and cubic roots: 4-5 seconds.
• Calculating trigonometric functions: 4-5 seconds.
• Calculating complex formulas (like (π^(1/2)*cos^2 x)/(x^(1/3)) ): 30-50 seconds.
Source:  «Кущенко В.С. Логарифмическая линейка.  — 1958»

#### CatalinaWOW

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##### Re: Slide rules
« Reply #51 on: November 09, 2019, 02:32:56 am »
Those times seem slow to me, maybe by a factor of two.  Based on my memories of slipstick days.  Of course the time depends on the specific numbers and where the rule was left after the previous calculation.  It certainly was that slow, or maybe a bit slower sometimes.
Just

#### Canis Dirus Leidy

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##### Re: Slide rules
« Reply #52 on: November 09, 2019, 07:45:38 am »
Those times seem slow to me, maybe by a factor of two.  Based on my memories of slipstick days.  Of course the time depends on the specific numbers and where the rule was left after the previous calculation.  It certainly was that slow, or maybe a bit slower sometimes.
The author also included the time needed to (hand)write the result on paper.

#### CatalinaWOW

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##### Re: Slide rules
« Reply #53 on: November 09, 2019, 04:20:06 pm »
So I guess the question is. "Is it faster to write the answers down on paper when using a calculator or a slide rule?"

Or not, it is a silly question.  The data can't be used to compare the two since intermediate answers are only written down occasionally with either tool.  Probably more often with the slide rule because of the need for additions/subtractions.

#### Johnboy

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##### Re: Slide rules
« Reply #54 on: November 10, 2019, 11:07:58 pm »
There were "slipstick contests" where the "fastest guns in the West" faced off with their slide rules to compute various equations. It was even a team sport at some colleges, apparently. I have yet to see any actual photographs of a slide rule team.

It seems that many of the techniques that were used to rapidly arrive at an "answer" have been largely forgotten. One of my favorite slide rule tricks I discovered playing around with them was one I later discovered was also used by the celebrated physicist Richard Feynman at Caltech during his lectures.

Feynman (as many of you probably know) was quite skilled at mental math without need of a pencil or calculator for many of the problems he demonstrated on the board. He could occasionally produce a correct answer, using his simplex Pickett rule, to include four or five figure answers. For multiplication of two given numbers, for example, he would mentally multiply the last digit of each number together, then pretend to find this final digit on the rule itself. He never admitted using the technique, exactly, but it's largely believed by the faculty that that's how he was doing it. Probably "old hat" to some of you who actually had to use a slide rule in school.

Anyway, speaking of techniques, I never bothered to learn how to use the CI scale at all until I read an English translation of one of the Japanese Hemmi manuals and it was quite a revelation. There are a lot of different ways to skin a cat using a slide rule, I guess is what I mean by this rambling post.
« Last Edit: November 10, 2019, 11:10:47 pm by Johnboy »

#### Nusa

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##### Re: Slide rules
« Reply #55 on: November 11, 2019, 12:30:31 am »

Quote
the older tools were not-so-gradually phased out of the educational environment

The "not so gradual" bit is rather true. Pocket calculators appeared when I was in high school. They wiped out slide rules overnight. One year slide rules were taught and used, the next year they had vanished.

True, right around 1974 if I remember right. However, they took a few years longer to wipe out teaching with trig and log tables, since the mass market calculators didn't have scientific functions. And the scientific ones were still too expensive for most (cheapest about \$150 in 1974).

I had one of those cheap round ones I used in 1972-3 High School Chemistry class. That was the last time I used it, too. I also have a couple of my Dad's slide rules now. One is marked ACU-MATH No. 500 and seems pretty basic. The other is marked Picket and Eckel, Chicago 3, USA, Copyright 1948 Model No. 500 Ortho-phase log log with scales I do not know the function of.

#### cliffyk

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##### Re: Slide rules
« Reply #56 on: November 11, 2019, 07:32:13 pm »
My first handheld calculator (ca. 1973 or so IIRC) was a Sperry/ Remington 661-0; a "full function" (+,-,*,➗) 6-digit, blue fluorescent display. No memory, but you had your choice of 2 or no decimal places; it was a marvel at the time:

Times have changed...
« Last Edit: November 11, 2019, 07:37:10 pm by cliffyk »
-cliff knight-