In 1976, a Texas Instrument cost $170 and a slide rule cost $3,75. What was a poor undergraduate to do? The profs accepted 6.8x10 to the 4th power. Oh by the way, you had to know your math.
Can you still buy a slide rule these days? When I went to college, the bookstore had them in various models from cheap to fancy. Seems like the fancy ones were bigger and had more scales on them.
New ones are still made by a Japanese company called Concise: they are circular. They have a couple of models which are real sliderules (logarithmic-based scales, cursor) and a few others which are more nomograms or slidecharts.
You can find old sliderules, some “old new stock” in original packaging, on ebay all the time. There are also books on archive.org and books.google.com that tell how to use them, and at least one mailing-list group, groups.yahoo.com/group/sliderule which is populated with sliderule users and collectors.
You can still use sliderules: Most of the teachers remember them, and will allow lower precision answers (two or three significant figures, generally) done on a rule instead of full-precision (often meaningless precision) answers from a calculator!
Sliderules are wonderful: they are a physical embodiment of calculation, generalized to universal application, or in other words, you can calculate just about anything with the right rule. Specialized rules included scales for particular jobs (electronics, RFdesign, surveying, chemistry, etc) but even the simple Mannheim rule can do squares and roots, multiply and divide, figure ratios, and do both chain calculations and series of ratios with ease. Add trig scales and log-log scales and you can do any power and solve amazingly complex problems.
What you cannot do with a slide rule is add or subtract (although there have even been rules with linear scales made for that purpose!) But since the scales lend themselves to approximation, rather than great precision, they encourage a sense of proportion and estimation and relation to the Real World. (Woodwork, for instance, can be done to .0001” with modern computerized routers, but wood swells ~1/32nd inch with mild humidity changes, so who needs more accuracy?)
The reason you don’t add with a slide rule is because it is already adding, but adding logarithms. (Remember the joke about the snakes on the Arc? God said “Be fruitful and multiply,” but they couldn’t: they were adders. So he had Noah make a log table, and then they were alright! Add logs to multiply!) That’s why the A/B and C/D scales are not linear: they represent the log values of the printed numbers in distances, and you use the slide and cursor to add or subtract the distances to multiply or divide the numbers. It’s even easier to do than to describe!
Just about every trestle/suspension bridge in the country, along with nearly all the great multistory buildings, ships (prior to about 1976), aircraft, etc and most of our space efforts were built on calculations done on sliderules! High-precision calculations were made only when needed on expensive large computers. Calculators have turned that upside down, though, but sliderules could and should still be taught in schools. (OK, I’m off the soapbox now!)
When I went to Naval Nuclear Power School in Orlando back in 1977, we used slide rules for our calculations. It also happened to be around the time that Star Wars first came out, so the slide rules made excellent ersatz light sabers for a bunch of geeks like us
wanderwolf about 15 years ago
That lets me out… if only because the only slide rule I’ve ever seen was in the cartoons.
Yukoneric about 15 years ago
I have two. One was my dad’s from 1946 and mine from 1966. I keep them at school to show the students how we used to calculate.
lewisbower about 15 years ago
In 1976, a Texas Instrument cost $170 and a slide rule cost $3,75. What was a poor undergraduate to do? The profs accepted 6.8x10 to the 4th power. Oh by the way, you had to know your math.
doghollar about 15 years ago
Can you still buy a slide rule these days? When I went to college, the bookstore had them in various models from cheap to fancy. Seems like the fancy ones were bigger and had more scales on them.
tiorbinist about 15 years ago
You can still buy sliderules!
New ones are still made by a Japanese company called Concise: they are circular. They have a couple of models which are real sliderules (logarithmic-based scales, cursor) and a few others which are more nomograms or slidecharts.
You can find old sliderules, some “old new stock” in original packaging, on ebay all the time. There are also books on archive.org and books.google.com that tell how to use them, and at least one mailing-list group, groups.yahoo.com/group/sliderule which is populated with sliderule users and collectors.
You can still use sliderules: Most of the teachers remember them, and will allow lower precision answers (two or three significant figures, generally) done on a rule instead of full-precision (often meaningless precision) answers from a calculator!
Sliderules are wonderful: they are a physical embodiment of calculation, generalized to universal application, or in other words, you can calculate just about anything with the right rule. Specialized rules included scales for particular jobs (electronics, RFdesign, surveying, chemistry, etc) but even the simple Mannheim rule can do squares and roots, multiply and divide, figure ratios, and do both chain calculations and series of ratios with ease. Add trig scales and log-log scales and you can do any power and solve amazingly complex problems.
What you cannot do with a slide rule is add or subtract (although there have even been rules with linear scales made for that purpose!) But since the scales lend themselves to approximation, rather than great precision, they encourage a sense of proportion and estimation and relation to the Real World. (Woodwork, for instance, can be done to .0001” with modern computerized routers, but wood swells ~1/32nd inch with mild humidity changes, so who needs more accuracy?)
The reason you don’t add with a slide rule is because it is already adding, but adding logarithms. (Remember the joke about the snakes on the Arc? God said “Be fruitful and multiply,” but they couldn’t: they were adders. So he had Noah make a log table, and then they were alright! Add logs to multiply!) That’s why the A/B and C/D scales are not linear: they represent the log values of the printed numbers in distances, and you use the slide and cursor to add or subtract the distances to multiply or divide the numbers. It’s even easier to do than to describe!
Just about every trestle/suspension bridge in the country, along with nearly all the great multistory buildings, ships (prior to about 1976), aircraft, etc and most of our space efforts were built on calculations done on sliderules! High-precision calculations were made only when needed on expensive large computers. Calculators have turned that upside down, though, but sliderules could and should still be taught in schools. (OK, I’m off the soapbox now!)
MisngNOLA about 15 years ago
When I went to Naval Nuclear Power School in Orlando back in 1977, we used slide rules for our calculations. It also happened to be around the time that Star Wars first came out, so the slide rules made excellent ersatz light sabers for a bunch of geeks like us
BigGrouch about 15 years ago
Never used a slide rule, but I do know how to read micrometers and vernier calipers.
James Lindley Premium Member about 15 years ago
I still have 2 sliderules.