A CONFIDENCE-LIMIT COMPUTER

A paper slide rule to calculate fourth from three known variables: upper confidence limit, confidence level, number of observations, and number of events with a specified characteristic.

https://www.osti.gov/biblio/4139048

#SlideRule

Interestingly, Leon Lalanne (inventor of the #abaque) also came up with a glass #sliderule, which had advantages over the wood version.

https://www.nzeldes.com/HOC/Lalanne.htm

@Sarah_in_sk There's bound to be a big #sliderule enthusiast section anyway :-)

@gutenberg_org @wikipedia
I am glad to know who is responsible for these #math concepts I take for granted. I got my first #calculator in 7th grade. Our math #teacher warned us not to rely on #calculators because "Sometimes they're wrong!" One of my #CivilEngineering #professors used a #SlideRule to show the importance of understanding the quantities we're working with rather than blindly accepting the results from a #computer. One #typo can lead to disaster. I now have my own slide rule.

This is a #Braille #SlideRule

Today's oddity: showed an actual degreed and employed #engineer how to use a cheap #Vernier #caliper to get accurate measurements down to 0.1mm.

Caveats: engineer is much younger than me, this was an old-school caliper without a dial or digital readout, their primarily field is fluid dynamics (so not a lot of calipers). And they understood the idea quickly.

But now I'm wondering this person would panic at the sight of a #slideRule. Tempting to throw one in the bag "just in case."

Just as an introductory post, here are a few interesting slide rules from my collection... #sliderule #sliderules

Important knowledge for all. #sliderule https://youtu.be/rJKmc4PVdh4

@VintageProject "My calculator app complains about no network connectivity. Quick, anyone, what's the inverse of pi squared?" #SlideRule

I really like how these seem to be coming up more regularly.
#Aristo Studio 868.
Really handy for your EDC. 😉

#SlideRule

And something new on the #SlideRule front, as well:
Found this nice #Logarex 27102 pocket slide rule. Made in Czechoslovakia by Bohemia Works.
Seems to be in perfect nick, but I don't understand the text on the back of the lower frame.
"Ocel, Litina, Hlinik, ..." 🤔
Need to do some googling.

New home for the slide rules, for now anyway. #sliderule #sliderules

Decided to organize the slide rules by manufacturer, because my office isn’t messy enough as is.

#sliderule #sliderules

Hand on heart: who here, honestly, without any prior research [to learn what the hell i'm even talking about] or practice [to polish a long-dormant skill], could today, if presented with a mathematical question, solve it using [any or all of]:

1. pencil, paper, long-division & multiplication, BOMDAS?
2. log-tables
3. slide-rule

🤨

#LongDivision #LogTables #SlideRule #mathematics

Subsidiary question: how many more years/decades before nobody alive knows any of those? 🤷‍♀️

Sterling metric converter, still sealed. (Although I don't care much about such things. I will open it.) 12" versions are fairly common, but this is the first 6" one I've come across.

#sliderule #sliderules

Latest acquisition is ThinkGeek's fairly recent take on a pastiche of Pickett slide rules.

#sliderule #sliderules

That's neat: The Nestler Rietz 0123 isn't that rare or special, but seeing one in original packaging is a feat in itself.

#SlideRule

When I was studying, a slide rule was all I was allowed to use for calculations, also on exams.

Simple #electronic #calculators existed already, but school boards didn't know what to make of these yet. So they were banned.

Watches with slide rules exist too and I have one of these, a #Breitling look-a-like.

On a side note: I found out that trying to explain how a slide rule works to modern day students generally fries their brains.

Just don't.

#sliderule #watch #watches #school #oldschool

Aluminium is nice, too.
These are GDR made by Reiss.

One had to be disassembled, and the rear cursor adjusted and glued back in place. Now drying in a vise.

#SlideRule

Side note: The 'D' means "Doppel', i.e. 'Double' or 'Duplex'.
The idea was to use a Rietz style #SlideRule with A, B, C, D, then add K and L, and a couple of LL scales. On the back, they added folded and inverted scales CF, DF, CIF, and trig scales S, ST, T1, T2.
That makes for a really good setup.

As a bonus, this slide rule was pretty popular and still isn't that rare or expensive.

It was produced between 1965 and 1973, according to museums. Probably also used as standard issue in schools.