A number of watches are still sold with flight computer slide rules in the bezel, including my current favorite the Citizen Nighthawk, which is a chrono-less sibling to the Navihawk, which is something of a budget homage to the Breitling Navitimer.
I find it quite handy in daily use, for example converting between Celsius and Fahrenheit, kilometers and miles, and currency conversions when traveling. I'll even use it sometimes when calculating a tip (the F<->C conversion of 1.8 conveniently aligns with a typical tip of 18%).
This page links to a physically unremarkable Soviet slide rule used for calculating things like the volumetric flow rate in irrigation canals used in Uzbek SSR for growing cotton, their primary cash crop [1].
Unfortunately, there are no scales on it for "evaporation" and "shitty construction", or the Aral Sea[2] might still be there.
What would be even cooler is if the website could turn some of the most interesting examples into spinnable (?), controllable animations to let you use them.
Slide rules seem very anachronistic but this is only because of the their form but not their purpose.
They are low-tech, continuous (vs. discrete, as in "tables with values in a booklet") lookup "tables" for functions that would have been too time-consuming (or error-prone?) to compute at "runtime". And they even allow parameters to be taken into account.
They go one step beyond lookup tables, though: they are lookup tables where also the input is (well, depending on scale) transformed with a mathematical function.
And if you talk about Germany, there's a whole museum dedicated to those in Bonn. The "Artihmeum". In the city center, by the university. It's huge, fascinating, and I believe I was the only person inside when I visited last year... They even let you use some of the originals.
I have inherited one of these. It seems to be a AW Faber 360 v2.
Tbh i never really looked into how it's used but after reading some comments i might consider learning it, it seems really useful !
It is incredibly useful in the kitchen still. That's the one place I'm actually surprised it isn't part of standard equipment.
If you have a series of numbers you want to scale by a known fraction, you can just set the slide rule so that the numbers in the fraction are over and under each other, then leave it there and even a two-year old can read off scaled numbers like it's nobody's business.
What does this have to do with the kitchen? The recipe calls for 50 g of butter, but you want to make as much as possible and you are constrained by owning 85 g of butter. Set slide rule to 85/50, then read all other ingredient amounts off the slide rule, scaled by the same amount.
My wife may have had one, though she would have called it a "proportion wheel"--people doing print production used these well into the 1980s and perhaps beyond to calculate the
reduction need to make photographs fit on a page.
In my view, the great think about slide rules is that they do not encourage false precision. Too many calculator users will copy all those decimal points without considering how far they are meaningful.
> In my view, the great think about slide rules is that they do not encourage false precision. Too many calculator users will copy all those decimal points without considering how far they are meaningful.
This is by far the biggest loss from leaving the slide rule behind. People now confuse a greater amount of data with having more information. We have generations who believe they're being more accurate because they appear have greater precision, but in reality they're just more confident in their innumeracy.
Hearing more lies (as in the the extra digits) doesn't make you more right. This truth does not just apply to arithmetic, but at least it's more measurable with numbers.
There were a bunch of both linear and circular devices that were basically slide rules customized for specific purposes. I'm sure I used one of the print production ones. This sort of thing stayed around for a while after slide rules themselves largely went out in the late 1970s.
I love the specialized instruments. The "Astrology Slide Rule" for calculating horoscopes and the "Bio Dial" for biorhythms. What a wonderful cross-over between hard science and fantasy.
One thing I've learned over the decades is it often benefits the craftsman to use a specific tool for a specific job. Sometimes a general-purpose digital computer is not the most appropriate tool when a simple hand-held analog device will give you the right answer every time without batteries or reception, in the rain or damp or cold.
I learned to use a slide rule as a youth because it was an important part of the high school science curriculum (how else were you going to calculate all those Ksp values in chemistry? Long hand?). I also have a pile of them I've collected over the years. Long may they, uh, rule.
Without computers, or at home away from the mainframe, we really had slide rules for just about everything you would need to routinely calculate.
A lot of them are sponsored or provided by corporations or trade associations, TRW provided the ICBM Effectiveness & Survivability model which looks really useful:
This is an outstanding black slide rule and its maker has remained anonymous, it's pretty dark but I guess a bright enough flash of light is expected to be available when you need to do this calculation.
Beautiful! ... I used some version of the CTCS-552 from 10th to 12th grade (and still have it around here somewhere). The slide-out card has trig tables and quite a few formulas. I also have one of my father's slide rules which he used for the first 1/3 of his EE career. There was a huge benefit of using a slide rule - it reinforces your "mental math" since you're keeping track of the magnitude of your calculations in your head. When I later started using a calculator, it was really obvious if I'd mistyped part of a calculation.
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[ 2.9 ms ] story [ 68.2 ms ] threadhttps://youtube.com/channel/UCOLYtsL4ge6QfaAvBDeG1IA
https://en.m.wikipedia.org/wiki/E6B
I find it quite handy in daily use, for example converting between Celsius and Fahrenheit, kilometers and miles, and currency conversions when traveling. I'll even use it sometimes when calculating a tip (the F<->C conversion of 1.8 conveniently aligns with a typical tip of 18%).
Unfortunately, there are no scales on it for "evaporation" and "shitty construction", or the Aral Sea[2] might still be there.
[1] https://osgalleries.org/collectors/davis/info_and_image.cgi?...
[2] https://en.wikipedia.org/wiki/Aral_Sea
There are more of them on that site.
They are low-tech, continuous (vs. discrete, as in "tables with values in a booklet") lookup "tables" for functions that would have been too time-consuming (or error-prone?) to compute at "runtime". And they even allow parameters to be taken into account.
These things are absolutely ingenious inventions.
Explanations on slide rules:
https://www.math.utah.edu/~alfeld/sliderules/
A "slide rule creator" program that allows you to generate slide rules for arbitrary functions that are computable with slide rules:
https://www.math.utah.edu/~alfeld/sliderules/SRE.html
* https://www.youtube.com/c/ProfessorHerning/videos
https://www.deutsches-museum.de
https://en.wikipedia.org/wiki/Deutsches_Museum
https://www.arithmeum.uni-bonn.de/
If you have a series of numbers you want to scale by a known fraction, you can just set the slide rule so that the numbers in the fraction are over and under each other, then leave it there and even a two-year old can read off scaled numbers like it's nobody's business.
What does this have to do with the kitchen? The recipe calls for 50 g of butter, but you want to make as much as possible and you are constrained by owning 85 g of butter. Set slide rule to 85/50, then read all other ingredient amounts off the slide rule, scaled by the same amount.
My wife may have had one, though she would have called it a "proportion wheel"--people doing print production used these well into the 1980s and perhaps beyond to calculate the reduction need to make photographs fit on a page.
In my view, the great think about slide rules is that they do not encourage false precision. Too many calculator users will copy all those decimal points without considering how far they are meaningful.
This is by far the biggest loss from leaving the slide rule behind. People now confuse a greater amount of data with having more information. We have generations who believe they're being more accurate because they appear have greater precision, but in reality they're just more confident in their innumeracy.
Hearing more lies (as in the the extra digits) doesn't make you more right. This truth does not just apply to arithmetic, but at least it's more measurable with numbers.
One thing I've learned over the decades is it often benefits the craftsman to use a specific tool for a specific job. Sometimes a general-purpose digital computer is not the most appropriate tool when a simple hand-held analog device will give you the right answer every time without batteries or reception, in the rain or damp or cold.
I learned to use a slide rule as a youth because it was an important part of the high school science curriculum (how else were you going to calculate all those Ksp values in chemistry? Long hand?). I also have a pile of them I've collected over the years. Long may they, uh, rule.
A lot of them are sponsored or provided by corporations or trade associations, TRW provided the ICBM Effectiveness & Survivability model which looks really useful:
https://osgalleries.org/collectors/davis/info_and_image.cgi?...
Even more handy would be the Ground Zero/Bomb Damage slide rule:
https://osgalleries.org/collectors/davis/info_and_image.cgi?...
This is an outstanding black slide rule and its maker has remained anonymous, it's pretty dark but I guess a bright enough flash of light is expected to be available when you need to do this calculation.