Slide rules rule!

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etotheipi
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Not very modern, but straightforward to understand. He actually does the experiment and analyses the results right in front of you.
Digression, but what on Earth is that ruler thing he's using to calculate products at 14:10 and 15:40?

Edit: I found it, it's called a "slide rule":
https://www.math.utah.edu/~alfeld/sliderules/
 
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  • #2
robphy
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Digression, but what on Earth is that ruler thing he's using to calculate products at 14:10 and 15:40?

Edit: I found it, it's called a "slide rule":
https://www.math.utah.edu/~alfeld/sliderules/
:smile:

possibly useful: https://www.sliderules.org/ virtual slide rules

possibly interesting:
https://www.physicsforums.com/threads/relativator-the-circular-slide-rule-for-physicists.767964/ (original posted in 2006)
1618252817936.png

updated link to the article on Symmetry:
https://www.symmetrymagazine.org/article/december-2005january-2006/artifact-relativator
 
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Digression, but what on Earth is that ruler thing he's using to calculate products at 14:10 and 15:40?

Edit: I found it, it's called a "slide rule":
https://www.math.utah.edu/~alfeld/sliderules/


Pretty ingenious, but thank gods for computers.
 
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DaveE
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Seriously, there is one great thing about slide rules. They only give you the mantissa, and just a few significant digits at best. This forces people to actually think about the calculation; built in error checking. An electronic calculator is quite capable of giving erroneous answers if you make a mistake (so will a slide rule), but people don't always do a sanity check. There is some value in using your brain to get a rough answer, before the machines give you a more exact solution.

BTW, my circular slide rule got me through High School Chemistry class and was then permanently retired, it now sits in a box of mementos.
 
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Hold on to your slide rules folks when the EMP comes you'll need them to rebuild civilization. :-)
 
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Janus
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Not a slide rule, but an old style "flight computer".

flight_comp.jpg
 
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Slide Rule vs Calculator Showdown: Decilon & HP-35​

 
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Keith_McClary
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Hold on to your slide rules folks when the EMP comes you'll need them to rebuild civilization. :-)
I'll just get some bamboo and make one.
S6300494.JPG
 
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I'm old and I've used slide rules. I remember the cheap, small models (5" long and a few lines). The "monsters" were about 12" long, 3" wide and had lots of lines. Quite useful (50 years ago). Perhaps, the last great survivor of the "analog" era is the Smith chart.
 
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I've got about six slide rules here at the house. Back when I first started college, there were no pocket calculators, so calculations were done using slide rules exclusively. About 10 years later, HP came out with the HP-35, which cost about USD300, and they still go for close to that.
They only give you the mantissa, and just a few significant digits at best. This forces people to actually think about the calculation; built in error checking. An electronic calculator is quite capable of giving erroneous answers if you make a mistake (so will a slide rule), but people don't always do a sanity check. There is some value in using your brain to get a rough answer, before the machines give you a more exact solution.
Or an "exacter" solution. Forcing people to actually think about the calculation is a good thing; otherwise it's garbage in, garbage out.
 
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I did my physics lab with a combination of sliderule math and adding machine math.

In some cases, i converted my data to logs, added things up and converted back to get a few more digits of accutacy.
 
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hilbert2
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Then there's this mechanical calculator first made by someone when being a prisoner in a nazi concentration camp:

https://en.wikipedia.org/wiki/Curta

Too bad that nowadays senior high school students are not even shown how to calculate approximations for irrational square roots by hand without a calculator. Except in some East European countries where there's more advanced math at that level of schooling.
 
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Scientific American did an article on these incredible devices.

https://www.scientificamerican.com/article/the-curious-history-of-th/

I recall someone saying you could never repair them because once you opened it the springs would escape and there was no chance of putting it back together.

i always wanted to own one but they were always way out of my budget even now.

They were also known as a pepper grinder because of their shape and the need to spin a handle.
 
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Keith_McClary
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I did my physics lab with a combination of sliderule math and adding machine math.

In some cases, i converted my data to logs, added things up and converted back to get a few more digits of accutacy.
That's nothing. I had to use an abacus and record intermediate results on a clay tablet with a stylus.
 
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Does someone remember nomograms?
 
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That's nothing. I had to use an abacus and record intermediate results on a clay tablet with a stylus.

Lucky bastid! We could only dream of having a stylus
 
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  • #21
Baluncore
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i always wanted to own one but they were always way out of my budget even now.
I find the details of computational instruments fascinating.

I keep a Curta on my desk, to remind me of that tragic past. My slide rules are in the draw, where their batteries won't go flat. There is a box of retired HP RPN calculators somewhere in the store. I keep a HP 48G under my pillow.

My Original Odhner LuSiD is good for 10 digits. I gave it a full service and taught myself to calculate square roots on it when it was over 80 years old. I now take it to "show and tell" events where I get to demonstrate what very few people have seen.
http://www.vintagecalculators.com/html/odhner_lusid.html
 
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  • #22
anorlunda
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Very nostalgic.
Does someone remember nomograms?
Ah yes. In my M.E. courses, we learned to make our own nomograms. Some of the homework assignments were difficult. You can be very creative about the position, and angles of the scales, and even use curved scales.
1618670684168.png


It might be fun to do that today. I wouldn't be surprised to see an online calculator that could do it for you. Young people might be fooled into thinking that it was a new invention.
Hold on to your slide rules folks when the EMP comes you'll need them to rebuild civilization. :-)
My Post slide rule came with a high quality leather sheath that could be worn on the belt. I still have it. Back then, there was a big social stigma about wearing it on your belt; very nerdy. Wearing it today might get you shot by police who think it must be a weapon, but at least you would have it with you when the EMP comes.


1618670468242.png


I also remember raging debates among engineering students about which was best, Pickett (metal) or Post (bamboo). My boss owned a one meter long Pickett slide rule. He claimed to be able to get one more significant digit in his results.
 
  • #24
Keith_McClary
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... slide rule came with a high quality leather sheath that could be worn on the belt.
In the campus lost-and-found they had a big bin of those, much better than my little bamboo model in the tattered cardboard box.
 

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