Ever used a sliderule?

[KitchenWitch]

How do they work?

[Speck Tater]

1. Constipated mathemeticians work it out with a slide rule.

[papau]

2. LOL - and in the 50's they paid $50 to $100 for a good K&E sliderule!

Another lost art!

As to how they work -

well moving two sticks in effect is the addition of stick one's length to stick two-

and adding two logs gives the log of the - of the what now... now ...

Feris - wake up! :-)

[TXlib]

31. No, they work it out with a pencil!

Get the damn punchline right!

[On the Road]

3. The Two Sliding Rulers

basically allow you to add different values. The different lines represent different functions you can perform (addition, multiplication, etc).

For addition, it's straightforward. Say you want to add 2 + 2. You locate the "2" on the top scale, line it up with "0" on the lower scale (the middle piece that slides). Then look for the "2" on the lower scale. The answer, "4", should be directly above on the top scale.

Nobody uses slide rules for addition, though. It's more trouble than it's worth with slide rules, however. Slide rules are more for other functions that are difficult to do manually.

For multiplication, the process is the same -- you find the first number on the top scale, line it up with 0 on the bottom scale, and check the corresponding value on the top scale. Multiplication uses scales that are based on logarithms. "Adding" the numbers on a log scale is the same as multiplying.

There are other functions you can do including exponents, and Trigonometric functions. They simply use different scales.

At least, that's how I remember them. Hope it helps. Someone can correct me if I misremember. You can even try it on the web here:

http://www.taswegian.com/SRTP/javaslide/javaslide.html

[immoderate]

4. Good explanation.

In the sixties some engineering students wore slide rules hung from a belt in a case, like a sword.

The story is that Leibniz, who discovered logarithms also created the forerunner of the slide rule called "bones."

--IMM

[On the Road]

8. I Was Hoping It Would Make Sense to Someone

rather than just confuse the issue. It's a lot easier to just show someone in person.

[Kellanved]

13. it's funny, considering that Leibniz also "invented" binary

:D

[NoPasaran]

17. Even geekier...

Some had miniature slide rule tie clips

[TreasonousBastard]

24. Perfect Geek...

that Java sliderule.

Now, if I just had a book of Trig tables...

[trof]

5. Sure have.

I could explain how a computer works easier.
I used one for most of my career.
On my desk right now is my old Air Force Type CPU-26A/P
"Computer, Air Navigation, Dead Reckoning"
It's a circular slide rule that I used to compute fuel burn, groundspeed, ETAs, etc.

[trof]

6. Here's a photo:

[alwynsw]

7. Round one or straight one?

We had to have them in high school for chemistry. A decent one went for around $10.00 in the early '70's. A good one cost a couple hundred. A friend who was an engineer for GE Aerospace loaned me his round slide rule. He said it carried a solid high B average at M.I.T. for him. Wish it had worked that well for me, but then, I'm an advanced math dunce.

[trof]

10. see above

[TrogL]

9. I had one with about 24 scales on it.

It was bright screaming yellow.

I've still got a smaller one lying around somewhere and still know how to use it.

[arwalden]

11. I Can Use One...

... to draw a straight line on a piece of paper.

[alwynsw]

12. Are you sure about that, A?

I have doubts... :silly:

[xray s]

14. Now that brings back memories

I was in high school in the 70's. My sophomore year I took Chemistry and we had to use a slide rule. That Christmas, Texas Instruments came out with one of the first pocket calculators. It cost about $100 (it only had a few function; basic math, square roots, I think that was about it). A few kids got them for presents, but our teacher wouldn't let them use them in class. He said they were just a fad, and you would always need to know how to use a slide rule.

By senior year, the slide rule was dead.

[BiggJawn]

15. I have several

I remember how to do SOME functions on them, but the LED-displayed "pocket" calculator became affordable just about then.

The prices they used to go for! I think I paid a buck last year for one that originally sold for $100...

[TheCentepedeShoes]

16. Not since HS chemistry

and please don't ask how long ago that was.

[ProfessorGAC]

29. I'm Askin'

Me, i took HS Chemistry in 1971 - 1972. As a glutton for punishment, i got my undergrad in Chem, then a grad degree in Quantum Chem. Fortunately by then, there were calculators with log and ln functions. Doing the quantum math on a slide rule would have been D-R-A-G, Drag!
The Professor

[TheCentepedeShoes]

30. Ok, OK

Junior year 1964-65. Ouch!! Took geology in college as my required 6 credit hours of science. Enjoyed geology alot.

[ProfessorGAC]

36. Ha Ha, Made You Say It!

The Professor

[mwb970]

18. Sure, used one every day

At Ohio State, 1967-72. I got a real high-quality one and yes, I wore it on my belt.

I also wore a "Sgt Pepper" badge (the one from the album, mounted on cardboard and laminated) every day my first year of college.

Good times.

[ewagner]

19. Groan....slide rule nerd here!

Used to walk around with one attached to my belt in high school.....

only the coolest of us nerds actually did that.....

still have one around here somewhere.

lessee...A scale to C scale for multiplication and division....using significant numbers????? damn ....I can't remember.......

[immoderate]

20. I have a five foot slide rule.

I found it in the math dept. supply room. Hadn't seen daylight in years. I wanted it for my modest slide rule collection. But I knew the laws. The school could not legally sell it or give it away. So I arranged to "borrow" it until the next slide rule class was taught.

--IMM

[hunter]

23. I envy you...

Yours is much bigger than mine.

When I learned how to use a slide rule it was like magic.

[immoderate]

28. Funny though. It doesn't crunch bigger numbers.

--IMM

[bleedingheart]

21. yes a long time ago...

one of my engineering profs showed us how to use them...actually very useful tool...

[MrSandman]

22. Used one....

or several.

Didn't get into the how behind them, thanks to TI.

I did love the abacus though. Still astound students with it.

[steely]

25. Count me in...

same story - early 70's HS Chem - the teacher told us about them, and said we could order a decent low priced circular slide for 5 bucks if we got enuff people. It had the periodic table on the back, and asorted functions/cheat sheet pull-out.

then I inherited one and used it in the army.

then I bought a casio (one of the first) and later a TI-30 when they started to come out. I still have the slide rules.

We have a very esoteric model at work we pulled from the trash - kind of like a long rolodex.

[qnr]

26. ages ago. There are websites available that explain the process

http://www.hpmuseum.org/srinst.htm

[prairierose]

27. Used one once upon a time...

but I'd have to look at one to be able to explain it again & I don't remember where I mislaid mine! In the days before little calculators, the slide rule was great. But I'm math challenged, so I loved mine.

[bmbmd]

32. Used a slide rule?

Heck, I won a MEDAL in slide rule. I even wore mine on my belt.

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[yellowcanine]

34. Yes I have. They had the original cursors (before computer cursors)

We learned how to use them in plane geometry. Along with the pocket protector, the slide rule was the essential geek accessory.

On edit: I believe the term then was "nerd" , not geek. Geek is a computer era term, I do believe.

[Ron Green]

35. It's good to hang on to analog awareness...

The slide rule sees the world in analog fashion, while the calculator, and the abacus, are of course digital. I like to keep analog awareness alive in my own head, maybe saying "It's a quarter to three" instead of "it's two forty-six." After all, our planet moves round and round, not in binary steps, and we can remain conscious of that when we think about numbers and math.

[Orsino]

37. Very well, thank you.

If all you need is two or three significant digits, a slide rule is almost as fast as an electronic calculator (just as fast for the real experts, I believe), and teaches one more about math.

[Padraig18]

38. Yes, I have.

The brother who taught chemistry insisted that we use them, and not calculators.

[tjwash]

39. Actually I have. I am so old, I remember the first TI calculator....

...that came on the market for a couple hundred dollars.