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The Sliderule As Paleo-Geek Artifact 170

hwestiii writes: "Geek identification methods have waxed and waned over the years. Back in the years when it was still not cool to be a geek, they were identified by their pocket protectors and calculators hanging from their belts. And way back in the mists of time, before most of the Slashdot crowd were even an item on their parent's life-project-plan, they were identified by possession of ... slide rules. I'm clearly dating myself by submitting this, but I owned and used slide rules as a teen, just as microelectronics was making cheap calculators possible. Nando times has an interesting link to a community of people around the country trying to keep the memory and spirit of the slide rule alive. Some may be wistful, some may think 'What the hell...?' Take a look." A quick look at Google's image search yielded some cool photos of both slide rules and the classic HP-35 calculator -- I wonder where the HP-35 my dad used to use has gotten to. Does anyone still use slide rules on a regular basis?
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The Sliderule As Paleo-Geek Artifact

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  • by Anonymous Coward
    My mother was an accountant. She used a Curta (mecanical Handheld calculator).

    I still have it, functional, of course. It is an amazing machine.

    History of the curta [], and a picture of the : model I []



  • How the hell can slide rules be considered news?
  • by Anonymous Coward
    You rule! The old UK monetary system rocks; I can't understand why they got rid of it. As I recall it, it's like this:

    1 pound sterling = 20s (shilling)
    shilling = 12d (penny)
    Bob = 1s
    Florin = 2s
    Crown = 5s
    Guinea = 21s
    haypenny = 1/2d
    farthing = 1/4d
    tuppence = 2d
    thruppence = 3d
    Groat = 4d
    Tanner = 6d
    1/2 groat = 10/6d

    What could be simpler??

  • Apparently I need to re-read Bob's Quick guide to the apostrophe, you idiots [].

  • by mosch ( 204 ) on Saturday July 07, 2001 @07:19AM (#102050) Homepage
    A frightening quote from the article:

    If California's energy crisis turns computers into pricey paperweights and makes AA batteries as scarce as vacuum tubes, Tom Wyman will still be able to perform vital calculations such as finding the square root of 144 or figuring the value of 2 to the power of 10.

    Are American's today really so uneducated that they can't find the square root of 144, or the value of 2^10 without using a calculator?

    Apparently the author thinks these are otherwise unsolveable mathematical mysteries... I sincerely hope he's not representative of the average man.


  • My Dad (an engineer) gave me a Bamboo K&E he got as a gift from his grandfather (a machinist) in the 1930s. It was a lovely piece of work, but I preferred an aluminum Pickett with its yellow face. It was more... modern.

    Sadly, I lost many of my better tools, including slide rules and great-grandfather's calipers and other measuring instruments, years ago. Good thing I have calculators and computers now.

    And for those of you who are not familiar with such things, all you *really* need to navigate is a sextant, a watch or clock, a chart, and a copy of H.O. 249. A compass is nice, but not totally essential. Now let's see how many "kids today" know how to swing a compass, eh? (Or even what that means!)

    A lot of what I know is now obsolete... how to prop-start a plane... how to balance dual, triple or quad carburetors... morse code... the list goes on, and it's a long one.

    But I don't feel bad. One day the "kids today" will have their grandkids look up from their voice-operated or neurologically-jacked computers and say, "Grandpa, what's a keyboard?" :)

    - Robin
  • > Hell, before July 4, a bunch of high school age
    > kids were asked what the Fourth of July was celebrating, and they
    > either didn't know, or thought that it was our independence from
    > France...

    Cool. The Battle of Hastings was July 4, 1066?


  • Except most private pilots now-a-days buy a hand held GPS and never use an E6B except during checkrides.

  • As mentioned, he has a site with sliderules on it. They didn't reference the site's address, but here it is. [].

    Secret windows code
  • My first encounter with a slide rule was after a high school math exam (back in 1987). I finished the exam, and walked back to hand it in to my teacher and saw him using one to calculate percentages with one. Intrigued, I asked him about it and he showed me how it worked based on logarithms. I thought it was really cool and asked him where I could get one. He reached into one of his desk drawers, which was full of them, pulled one out and gave it to me. Thrilled, my next stop was to the library to find any books I could get my hands on about how to use one. Taught myself the basics of using a slide rule. I was even using it to do some of my physics homework when I got into university. I hadn't gotten very fast at it, but i could get the right answers. Then I got myself an HP-28S, and the slide rule now sits on my shelf with my collection of artifacts. I still pull it out now and then to play with it and show it to the occasional person that asks about it.
  • Hi Mike. Welcome to the club.


  • I have a friend who teaches in a local high school. This year one of the math teachers decided to throw out a lot of the older math teaching aids, including a 7 foot slide rule! When my friend heard about it, he immediately thought of me. I've now got my mondo slide rule propped against an upstairs wall, waiting for those really big problems to roll in...
  • I remember back in college (circa 1991) going into an engineering professor's office and seeing a gigantic wooden sliderule about 5 feet in length. Apparently, the engineering fundamentals program spent the first few weeks using such props to instruct engineers-to-be on the finer points of how to use a sliderule. Now they just teach them how to use a high level language like Matlab, tell them to forget common sense, and always believe the answer that the computer gives them.

    Sliderules should be used as part of an engineering appreciation course along with hand calculations and calculators that cost $500.

  • Tell that to people 20-30 miles away that would not be blinded by the flash in a bombing with a stolen missle.
  • When I learned calculus, I never bothered with a graphing calculator; I figured that it was too much bother and expense to get one of those things, and besides, I'd be better off in the long run learning how to do that stuff in my head.

    Turns out I was day I walked into a Physics exam and my (scientific) calculator went bust before the exam started. (This was Physics 152 at Purdue University...very painful course.) Because I was able to do the math mostly in my head, plus some pen-and-paper work, I managed to finish the exam, without a calculator, with a half hour to spare, and still get a 90%. I think the cutoff for an A was something insane like 66%.

    It made for an interesting discussion with my study partner:
    partner I got a hundred.
    me I got a ninety. But I have a good excuse.
    partner Oh really..
    me I didn't have my calculator.
    partner Oh. (pause) That's a good excuse.

  • >Apparently the author thinks these are unsolveable mathematical mysteries...I sincerely hope he's not representative of the average man.

    I hope so too, but I fear he may be....

  • The link: html

    n76lima had a space in the link.

    "Man könnte froh sein, wenn die Luft so rein wäre wie das Bier"
  • WTH? html []

    Oops, and then I added a spaceThere were more spaces than I thought. ;)

    "Man könnte froh sein, wenn die Luft so rein wäre wie das Bier"
  • "users still had to figure out where the decimal point should go. (Multiply 4 by 5 on a slide rule and the answer is 2, not 20.)"

    This would cause problems with some people I know that use calculators to multiply and divide by 10..
  • The point is that 144 is a perfect square and that the square root of 144 is 12.
    And 2**10 is 1024.
  • He killed himself after the War Department decided to use his "invention" (which he called 'graphitics') for piloted missiles whose crews would be on suicide missions, of course.
  • Isn't it the next logical step? I mean, after square watermelons and all.

  • Insurance underwriters use an "Easy Rate Wheel," or circular slide rule. On simple coverages, this enables them to get a rate, payment plan, tax, deductible, etc. in a few seconds.

  • A sovereign is a pound, so it's twenty shillings. It's sometimes shortened to 'sovs' (as in five sovs == five pounds), but not used a lot as slang these days. 'Quid' is the common slang for 'pounds'. To contribute to more topic drift, here's [] more info on slang names for British money.
  • You missed out the half-crown (2/6). Groats disappeared in the 19th century, and the farthing was discontinued in the 1960s.

    Also, your notation is a little confusing (!). The common way to write an amount of shillings and pence was ss/dd (d=pence, from the Latin 'denari', obviously). So, half of five shillings (a crown) is two-and-sixpence, which is 2/6. A ha'penny is half a penny, but 1/2d could be confused with one-and-tuppence (i.e., fourteen pence). Similarly, a farthing is a quarter of a penny, not one-and-fourpence. And since a groat is fourpence, half a groat is tuppence, not 10/6d, which is half a guinea.

    There were copper-type coins for the farthing, the halfpenny (==ha'penny), and the penny, a twelve-sided bronze-type coin for threepence (known as the thruppenny bit), a tiddly little silver-type coin for sixpence, progressively larger silver-type coins for a shilling, two shillings (formally called the florin, but everyone just called it two bob), the half-crown and the crown (which was about two inches across), then the notes started at ten shillings (== a ten bob note), a pound, five pounds, ten pounds, etc.. If there was an official coin or note for the guinea, I never saw one.

  • by wirefarm ( 18470 ) <> on Saturday July 07, 2001 @07:58AM (#102071) Homepage
    I can't be the *only* one posting to slashdot from a Kueffel & Esser Duplex 4080-3 rule, can I?


    MMDC Mobile Media []
  • You can use the time between each 'hit' to determine the length of the implied pulse, for all but the last pulse of the letter.

    However, most of the time, another letter follows each letter, so if you allow for a slightly longer pause, then you can usually guess what the duration of the last pulse was. Even if you can't, you can make an educated guess. For example:

    If you hear: hit---hithithit, that could either be a B (dah-dit-dit-dit), or a X (dah-dit-dit-dah). IF the next letter you hear is (hithit---hithit), that could only be an L. An X is very unlikely to precede an L, so you assume its a B.

    Yes, its much tricker than standard morse code, but if you're in a jail cell with nothing else to do.... ;)

  • Good ol' Jeppesen E6B flight computers []. I've got one that's about 15 years old. Tough as nails and works well too. Actually, I'd be surprised if most airline pilots didn't carry these for backup.

  • Check out this page [] where there's a detailed analysis of slide rule prices (top quartile, bottom quartile, median) on eBay .

    The table is based on rules sold on ebay from December 1999 to June 2000 inclusive.

  • I do the same with my full-featured K-E log-log deci-trig etc. slide rule at the office. Some problems are perfect slide rule problems, this is one of them. Anything involving similar ratios where 2-3 digit precision is fine. Set the rule once and read off the height of the graphic for any column width.

    It also elicits wonderful looks from my coworkers.
  • In a lot of k-12 schools calculators are bought for *every* student starting out in kindergarden. This boggles my mind for the same reason you point out; You should be able to know about where the answer should be. Using/depending on calculators hinders this process, you rely more on the output of the LCD, then your own brain...

    HP48GX user, and damn proud....

  • However, the calculation they were performing was addition, and I'm told that this is something slide rules can't calculate.

    Addition is the fundamental operation on a slide rule. (1.27 inches plus 5.31 inches is 6.58 inches...that's what all the sliding is about!) Multiplication is done by adding logarithms.

  • I took the SAT at least once a year back in high school. IIRC my junior year was the first time that calculators were allowed. I figured I'd go for the weirdness angle and brought my Dad's bamboo K&E slide rule, complete with the hardened leather scabbard hanging at my belt. The proctor let me use it, and I got my highest score on the math section before or since.

    The great thing about slide rules is that they were laid out in order to facilitate calculations, according to the order in whcih calculations tend to be done. Do one, flip it over, do another, flip over again, and so on until the answer was obtained. Besides, using the rule one gets a feel for numbers and math as something real, not something made-up and irrelevant. Man, I loved using that slide rule. Sigh...

  • Not airline pilots (someone please correct me if this is true for anything other than Air Zambia) but I know a number of private pilots - both powered and glider - that use them. No batteries, no hard-to-read displays, gives the right answer nice and quickly too :)
  • It was an integral part of my costume, second only to the printed circuit board motif. See [] or go straight to the picture [] and explanation [].
  • "I didn't know how to speeel engineer, and now I are one."

    You don't know how to spell 'linear' either.

    And it's 'oscillating'.
  • Except most private pilots now-a-days buy a hand held GPS and never use an E6B except during checkrides.

    Their loss. I'll put money that I can outrun them on a standard E6B for working time/speed/distance. Just dial in your ground speed and read off the time between checkpoint after checkpoint.

    Then again, I was annoyed when my examiner made me turn off the VOR receiver for all of my cross country. Hey- he's the one that gave me a route between two VORs. Everyone has the equipment they get used to...


  • I had an experience last semester at my high school where a sliderule really was a paleo-geek artifact. While replacing a row of old lockers, the janitors at our school (HHSS, Ontario) found an old slide rule underneath! It had slid under a locker sometime in the last fifty years or so. Our OAC calculus teacher (OAC is Grade 13, for you crazy Yankees) acquired the rule from the janitors who found it and brought it in to class. Everyone oohed and aahed over it, and the next day one of my friends brought in his dad's old slide rule with a sheet of instructions. I learned how to operate the excavated slide rule and did a whole class with it.
  • > Not airline pilots (someone please
    > correct me if this is true for
    > anything other than Air Zambia)

    Airline pilots do use them : it's mandatory to have a set of slide rules in the pilot's bag jsut in case all other equipment cease to function despite the n-levels of redundancy. They are seldom used in actual operation, but from time to time, a simulation scenario requires them to be used just to keep the skill sharp. Also, they are part of authorized tools during exams.
  • Once, I asked one of my instructors about their policy regarding programmable calculators and exams. He said if one understands a concept well enough to program it into a calculator, then one's grasp of that concept is such that the presence or absence of a programmable calculator isn't going to make a great deal of difference. I thought that was a cool attitude.

    I wasn't given any grief when I pulled out my Palm III to grind through some arithmetic on one of my finals...and that's a device intended to hold notes and such (even took all my notes one semester with it, though I switched back to dead trees this past semester as entering equations into Memo Pad is cumbersome). I might've had the first week's notes in there...but since we were allowed both sides of a page to set up as a crib sheet (mine done in 4-point text in Word with so many equations on the page that it started screwing up), the presence or absence of notes in the Palm wouldn't have made much of a difference.

    (All I used was the calculator. I don't carry a separate calculator anymore as a Palm does all that a calculator will, and then some. I've never had a graphing through math and physics with a TI-68.)

  • My K&E Decilon is still slip sliding along.
  • It's scary the calculations you can do using nothing but your brain and a hunk or rotating metal (or plastic, depending on your taste).

    Heresy, I tell you. Heresy. Being able to do calculations without using the Holy Semiconductor!
  • Oh yes, and I forgot to mention the backside of the Wonder Wheel does vector arithmetic, although you have to be careful to use a pencil when making the dot, or you won't be able to use it again without annoying yourself.
  • I was an undergraduate in 1974, and pocket calculators were still controversial -- professors railed against allowing them to be used on exams, etc. -- so kept using my slide rule (it's on a shelf not 10 feet from where I sit, covered in dust.) That year, I got my first account on a UNIX box, which came with dc and bc, and I've never since been tempted to buy a pocket calculator.
  • Incorrect. There are various rules on a SR. Two linier rules make for addition. One linier and one geometric make multiplication and division. One linier and one expoential... make a guess.

    One Linier and one ossolating (sp?) rule make sin/cos/csc/sec and tan/atan with a bit of work.

    At the request to my parents for a birthday present, they had to goto a mesuem gift store's deep storage to get me one.

    I didn't know how to speeel engineer, and now I are one.

    JLC B.Eng
  • I found a lot of satisfaction in shooting the stars and getting a nice position fix.

    Well, that's a decision everyone must make for himself. Personally, I enjoy brewing some coffee and getting a nice caffeine fix, but whatever. One man's cheese is another man's rotted milk.


    Um. We're not talking about the same thing, are we? :-)

  • My math teacher in high school (the best high school teacher that I had) used to tell us about how he and his friends used to carry their slide rules around in holsters. When someone had a math problem, they would would whip out their slide rules from their side holsters and see who could do the computation the fastest!

  • It's now cool to be a geek?
  • by Old Wolf ( 56093 ) on Saturday July 07, 2001 @07:42AM (#102094)
    Are "American's" today really so uneducated that they can't use an apostrophe correctly?
  • Last semester, I attended a course of Electronic. It was really interesting although the teacher was kind of crazzy. During the exams, calculators were forbidden but slide rules were allowed.

    It's sad I could not find one, anywhere..

  • I always thought that nuke yield data was classified?
  • by sconeu ( 64226 ) on Saturday July 07, 2001 @09:07AM (#102097) Homepage Journal
    I still have my KK log-log duplex. I need a new index though. The glass cracked.
  • Whew! That's cool. This is a great thread. I remember, vividly, the day my dad brought home one of the first HP-35s. And a slide rule. The slide rule was for me, so I wouldn't grow up to be a math cripple. I was crushed. But I learned how to use it... ;)
  • Of course slide rules can add. Everything they do is addition (*); it just happens that if you do addition using a log scale, the net result is multiplication.

    If you use a linear scale (which any decent slide rule had), addition is... addition.

    (*) or simple table lookup; typically you'd have a few trig tables to play with as well.
  • I see, so you prefer to argue accuracy over precision? I can see your point, but it was never assummed that the values of x.xx and y.yy were measurements or approximations due to measuring. Taken as exact values (as implied by not stating the source or other information), x.xx by y.yy will result in zz.zzzz.
  • the price of their tools.

    The Romance of the Slide Rule is very much alive today, the love affair is just transferred to the modern version of the tool.

    Slashdotters and Tom's Hardware afficionados who explore every capacity and foible of their machines are following the same urge as slipstick experts who practiced use of the LL/0 scale (which did an e^(-x) operation in one move) just so they were prepared should it come up one day.

    I must be almost the same age as "timothy" who started this article - it was slide rules for us up to about grade 12, when the richer kids were all getting calculators that did more than 4 functions...then in University, calculators were suddenly essential (but I carried the Rule to exams in case of battery failure).

    What I remember is that most geeky kids were old enough to *learn* to use a slide rule at the start of their teens...right around the time you get coordinated & generally grown-up enough to be allowed to touch precision tools. And slide rules, with their fine machinining, high cost, and smooth movement (metal sucked; bamboo rules...mine still work perfectly after 25 years in the drawer) were clearly *TOOLS*, not toys.

    A slide rule was a grown-up possession, a minor Rite of Passage.

    I don't think slide rules will ever be forgotten as long as dad's, grandad's and great-granddad's get found in attics. But what worries me is my Dad also taught me dozens of MENTAL calculation tricks that nobody needs any more.

    The easiest one was squaring number that ends in five. Chop off the five. Multiply the rest by one greater than itself; tack 25 on the end. (i.e. 35 squared: 3*4=12, the answer is 1225.) The hardest was memorizing ten anti-logs to three places; you can do remarkable estimation-level calcs with that one. (I've long forgotten them.)

    Anybody ever done a web page of those tricks?
  • Wasn't there a whole other variable, as well? The material of the coin?

    I recall that guineas weren't just an extra shilling compared to a pound, they were GOLD - and professionals & gentlemen took payment in gold, by preference.

    And aren't you missing a unit? Sherlock Holmes stories keep mentioning a "sovereign" and I think that was a gold coin, too...but how many shillings was it worth?
  • My dad is a civil engineer, and used a slide rule daily in his design work. Therefore he made sure that I had a good one. He had other, much more exotic tools too, such as a polar planimeter. This is a wondrous device that lives in a felt-lined case. You put it together, set it on a drawing, and run a little wheel around a closed figure. From a dial, you read off the area of the figure. It's a mechanical integrator. It's gorgeous. He sold it when he retired. OW!

    But I still have my Pickett. It's true that in order to use it, you have to place the decimal point yourself. In scientific calculations this isn't usually too hard, because you start with numbers between one and ten, and figure the exponents separately. The downside is that answers are inexact. You're lucky to be able to carry three significant figures, and you can't even do that if there are more than two or three steps in your calculation. Really, really serious people used very large slide rules with temperature compensation scales (!!!).

    The family company had those brute electromechanical calculators with ten-by-ten fields of buttons. Every ten years or so they'd replace the current ones, so when I hit college, I got one of those as a hand-me-down. It must have been almost solid steel, and weighed about forty pounds. I never looked back. Finally I had something that wouldn't reduce a calculation to mush by the fifth step.
  • Maybe your calculator's no good. If I for example do 4.44 * 6.66, I get exactly 29.5704 as a result. Seems to be the right answer as far as I can tell.
  • I use a slide rule quite often for converting between, say, pounds and kilos. Since I can just set it and read off the requisite weights, I don't need to get it dirty.

    ObSad: Mine is a British Thornton AA 010 Comprehensive. Made in England, don't you know!
  • That reminds me of a great Isaac Asimov short story I read. "The Feeling of Power" is its title. Taking place in the not-so-distant future, people have become so estranged from basic mathematical abilities that they have not even dreamed it possible to perform mathematical calculations without their pocket computers. However, once a bored technician teaches himself to multiply numbers with only a pencil and paper, whole new possibilities in warfare are re-opened. Eventually, this technician commits suicide because of the disasterous results the discovery of what he thought was just a harmless hobby had. It's very satirical but illustrates how we are becoming increasingly alienated from the roots of the things we use every day.

    You can read it for yourself at [].

  • Among the stranger items in my collection is a circular slide rule used to calculate nuclear blast effects. You can calculate crater size, overpressure, distance to second degree burns, instantaneous radiation, broken glass missile velocity, and all sorts of other hideous stuff with this little gadget. It comes in a pocket in the back of "The Effects of Nuclear Weapons" 1964 - US DOD/AEC.

    My mother was a 9th grade math teacher, and had a giant Pickett slide rule as a classroom aid. I don't know if we kept it after she died, but it was about 3 feet wide and 6 or 8 feet long.

    As a geek of the '60s, I had a full size Pickett, but my favorite "pocket protector" item was a nice little pocket slide rule. I remember engineering and physics courses where the early review was how to keep track of magnitudes and precision while doing slide rule calculations.

  • I have a Pickett TS-5 purchased at the Georgia Tech bookstore fire sale in 9/74. This is a log-log/deci-log slide rule that I still use to show my daughters (and dot-com youths) how to use.

    My first calculator was an HP-35, but I think I thew it out around 1984 when the batteries died and I could not get any replacement from HP. I owned it for 10 years, washed it twice (don't ask, but it was almost waterproof) and it was dropped from second and third story windows onto grass and hard dirt. Duct tape held the battery in after the little wings broke during one of the falls.

    RPN rules. TI still sucks and I still struggle with the '=' key on non-HP calculators.
  • by Greyfox ( 87712 ) on Saturday July 07, 2001 @07:25AM (#102109) Homepage Journal
    As a teen I found Dad's slide rule in the attic. By this time they'd mostly been replaced by calculators, but the manual that came with it was enough to figure it out and it really was a pretty simple solution for what it did.

    A while back the Navy stopped teaching older navigation styles, I gather because GPS is so much easier to use. And easier to jam. Sometimes progress is not a good thing and can actually do us harm.

    I think teaching at least the basics of these older methods of computation would be a good thing. We should preserve at least the knowledge that they're possible and a basic understanding of how they worked. It could be handy, for instance, to know how to find North using just an analog watch and the sun. Or a digital watch. Would have made The Blair Witch Project a much shorter movie though. "Ok, that's north, so the road is that way! Let's go!"

  • I own a dietzgen metal slide rule and a Post bamboo slide rule.

    I was in the last class in high school to learn how to use a slide rule in chemistry. When I went to engineering school I was in the first class to require a scientific calculator.

    As a freshman I carried my slide rule with me in my pack as calculators were still to expensive and a little delicate to be walking around with. My Econ prof asked the class if someone would divide two numbers for him. A few students pulled out calculators as I pulled out my sliderule. Natuarlly I had the answer first - sliderules are so much faster than calculators - so I answered his question. He turned to thank me when He stopped mid sentence to ask me "What is this?" - I told him it was an energy efficient calculator. "What will they think of next ;)"
  • My Dad, sensing the geek in me, taught me how to use a slide rule when I was a wee lad. At the time calculators were around, but were expensive and used batteries fast on their red screens. The LCD calculators came around about 10 years later, and made batteries last a long long time.

    I still have that slide rule though, and I can still use it. But DrGenius is generally faster and closer to hand.
  • by 4of12 ( 97621 ) on Monday July 09, 2001 @06:28AM (#102113) Homepage Journal

    Damn, and I've just gotten rid of my slide rule, pocket protector and flood pants to pay for a white leisure suit, gold chains, and disco lessons!

    I'm a true geek, always out of phase with current fashion...

  • You are right that American public schools scuk. But you are wrong about why. It has nothing to do with technology. It has everything to do with society.

    As most of us here are well aware, children who strive to excell as educaton, and learning in general are ridiculed and hated by classmates and teachers. That is the problem. American society is more focused on Basketball, and MTV than on real education. Even in college (just graduated, BS CS. WOOHOO!), I met teaching majors who were more concerned with the quarterback than with learning. They thought I was a little out of touch, because I don't even know who played in last year's superbowl, but can do multivariable calculus. AND THESE WERE TEACHERS!!!

    Comming from a poor out of the way mining comunity, I've seen education both with, and without technology-it makes no difference. But when teachers, the very people whose responsibility it is to educate children don't even get intersted in education, what else can you expect? In all my time as a student (before college) I found only one teacher who was genuinely interested in education. ONE, in 12 years. And thank god I did too! I will be forever indebted to her for what she did.

    Want to see a change in American education? Change the teachers. Get smarter teachers. Get teachers who have a passion for learning, and who have taken a personal stake in education. Don't blame technology.

  • I'm sure that when slide rules came out, your intellectual ancestors were just as adamant that the young people needed to be taught to do their math in the dirt with a stick, in case they ever broke a sliderule.
    So... are you suggesting that we shouldn't be teaching children how to add base-10 numbers by adding columns and carrying the overflow, but rather just teach them which buttons to push on a calculator? Dirt, paper or mental, the argument is the same.

    I fail to see how the ability to do math mentally should be replaced by instruction on how to use calculators. Or, as the article had it, determine the square root of 144 or 2 to the power of 10. These can be done mentally more quickly than they could be punched into a calculator. If you didn't have to do it mentally, you could pass your math tests by reading the question "What is the squre root of 144" as "enter 144 and press the square root button" rather than "what number squared gives the result 144?" In other words, it makes it possible to get a "A" without even understanding the question.

    At university, I initially found some of my computer science courses a bit abstract, and they seemed slightly pointless, but it was explained this way: we were being taught skills that would be relevant and useful regardless of the changes in technology.

    You can use then use the computer to find out how to run a slide rule if you are so inclined.
    Teaching that would take, what, a day? An hour?, there, done. Now can we teach them skills they will use regardless of the direction technology takes? Hoping kids stumble across useful information is NOT what education is supposed to be about.

  • The real skill that employers need is the ability to APPLY math concepts.
    I think that was the point I was trying to make... the slide rule IS an application of mathematics to the physical world. As several posters pointed out, it can also give an intuitive and visual understanding of how logarithms work. That would seem to me to be a valuable tool when teaching logarithms, and an example of the application of mathematics, and of problem solving using mathematics. Whether they'll ever actually need to use one seems beside the point.
  • I've got a sliderule in my calculator collection. The cover has the "Intel Inside" sticker on it, from my first computer (486/66, Linux 0.99p15.) There were problems at highschool I could figure out several times faster on a sliderule than a calculator.

    I've got an HP-35 too. Curiously, just today I browsed e-bay for the very first time and saw a bid of about $350 for an HP-35 - this is really silly, there are lots of them still around. My HP-46 is a *much* rarer beast. (I've got 11C, 15C, 16C, 18BII, 19C, 21, 25, 32E, 34C, 35, 41C, 45, 46, 48SX, 55, 65, 67, 80, 97 - from memory, it's a while since I've revisited the collection.)

  • Yup, I still have the simple slide rule I had for freshman year back in Engineering school. Also have my dad's HP-35 up in storage, although it needs a battery.

    Hi everybody. My name is Mike, and I'm a geek.

  • Actually, there is a story at the University of Chicago about Enrico Fermi that more or less is along those lines.

    During test blasts during the Manhattan Project the engineers would set up all sorts of equipment to measure the shock waves in the ground to estimate the energy in the blast of the atomic bomb.

    During one blast, Fermi tore a piece of paper into small squares and dropped them on the floor of his bunker. During the blast, he looked at how far/fast the pieces of paper traveled. Then, knowing the distance of the bunker from the blast, and God knows what else was in his head, he used his 6" slide rule and calculated a result that was within 10% of what the monitoring equipment and involved calculations revealed some time later.

    The lesson of this was supposedly, the bigger the mind, the smaller the slide rule.

  • A classic SF cover from the 1930s shows somebody climbing a ladder with a slide rule in his teeth!

    I still have a K&E Deci-Lon, with leather holster, but haven't used it in years.

  • Tom Wyman will still be able to perform vital calculations such as finding the square root of 144 or figuring the value of 2 to the power of 10.

    Um... I don't think any good geek needs help finding the square root of 144 or the value of 2-to-the-10.


  • by Gorobei ( 127755 ) on Saturday July 07, 2001 @02:47PM (#102132)
    I don't think this skill has been lost - I've seen many people I work with pull of similar tricks. E.g.
    • How many days to fill an 80GB harddisk from a 760Kbs DSL line?
    • Answer given before calculators are even picked up (need to know 80K seconds/day.)
    • 6/7 to three sig figs.
    • Answer is immediate if the useful 7*11*13==1001 has been memorized.

    So much of fast calculation is just knowing useful transforms (e.g. Pi seconds is a nanocentury.)

  • by starseeker ( 141897 ) on Saturday July 07, 2001 @09:07AM (#102135) Homepage
    This is an indication of a much larger problem we have with eduction in America. We are taught to USE things, not to UNDERSTAND things. In my NOT so humble opinion computers have no place in education before graduate school, unless they are taught as a subject in and of themselves, not as a substitute for thinking. In this I count TI and HP calculators as computers, how be it small and not really general purpose computers.

    I am of this opinion for the simple reason that I have fallen into that trap. I did not have any experience of any note with computers before college, except for one programming class in high school where we used rather pathetic machines at school to work. We had no computer at home except a dedicated purpose word processor. My calculator was not capable of symbolic integration or any of the other nifty tricks that the 89 and 92 are capable of. EVEN SO, the calculator could do logs, roots, and other things that I still have no good intutitive feel for. We need to be less concerned with speed in our teaching and mroe concerned with quality. Basic principles and techniques that have been really learned, not just memorized for a test and forgotten, will be of far more use than quickly picking up a broad survey of concepts.

    Students, most of them, don't really want to work hard. It's just not fun. That's where teachers and yes PARENTS need to impose a little disicipline. Not too much, because then it is only the threat of the whip which drives the kid and as soon as the whip is gone (college) the effort goes too. But external disicipline is extremely important in the early years. Just be sure that real learning takes place, and real benefits occur. And show the kid what these benefits are. Don't just say "It'll be of use to you in the future." That's fine for you, but a young kid has no concept of his future. He doesn't see the impact of the past on his present, because he hasn't had enought experience to note cause and effect in his own personal life. Show him/her what they've learned, be excited about it, and if they ask what good it is TELL them. Explain to them about the importance of understanding what's going on around you. Explain to them what science, engineering, and other mathematical endevours mean to their future. Don't assume they won't understand. Just be patient, don't underestimate them, and don't overestimate them. Encourage questions. Never belittle a child or scold him for asking a quetion again and again - if he/she really doesn't understand, you WANT them to keep asking rather than surrender to ignorance.

    There is a stigma in American society that if you don't advance a grade each year, you are stupid and behind. Behind in what way? I'd say if you falsly promote a student up a grade they'll be behind all their life, not just a year. Yes, social pressures can be cruel. I've lived through being the oddball and nerdy one all my life, and been shunned and made fun of. But you at least learn when to listen to people and when not to. A useful trick, when you deal with hostile people out in the real world.

    Actually, I dislike the use of the phrase "the real world" when applied to the world outside school. For a child, the school world can be horribly real. They are trapped there. All too often, real work ethic is ridiculed, and they get mixed messages from all sides. Parents are essential to provide a clear signal, but even they can do nothing when a student is on the playground being shunned.

    I am becoming a huge supporter of home schooling. Have activities where childern interact with each other, but keep learning between the parent and child. Both people involved are thus committed to what needs to be done, and the child can work at his/her pace, whether or not that is faster or slower than average. Also, the parent can then make sure that real understanding and absorption are taking placce, not just memorizing.

    And also at home, you can keep them free of electronic aids. I have no problem with computers being TAUGHT in education, but I have a big problem with them being USED in education. If schools want to teach computers, they should teach what makes them work, the history of computers, programming languages, and other basics. If they want to teach how to use computers, I have to pieces of advice. Do not teach any math, spelling or other "educational tool" software until college at the earliest, and do not teach just one system. Teach them to be flexible computer users. Explain how a computer virus works, why they need to worry about them, and how to think about security. Teach them the difference between OS and application, and introduce them to all kinds of both. Hard, you'd better believe it. But very much worthwhile.

    I would dearly love to see slide rules come back as a tool in teaching. An intuitive understanding of the world is where fundamental breakthroughs come from. It's also a great source of pride and confidence. Slide rules help build intuition, because the user is involved with the process of solveing. A calculator has none of that.

    It is probably too late for me - I doubt I will ever develop the intuitive grasp of the world that the great scientists of old had. Indeed, I seriously doubt most people who have let machines do any significant part of their thinking will. Has anyone noticed how large the precentage of foreign nationals is in our highest education setting, graduate school? So few Americans are there. We just don't have the interest, or the intuition, or the training to want to do it. We pride ourselves on being advanced, but the people responsible for so many of those advances used so many simple tools to learn, REALLY learn, the basics. No computers, no calculators. Pencil and paper, and maybe a slide rule. Basics students don't need more than three sig figs - they are learning BASICS.

    Pardon the rant. But this is a serious problem. I think home schooling may become more and more the way to really teach students. Make learning a life long excitement, not something to finish and then do something else. We push too hard, too fast. We burn out. I know what that is too. We need to question both our means, and our ends. I pray that someday we will.
  • makes me feel old. My daughter just turned 21, my slide rules are older than her.

    I've got two Picketts. Same as used on Apollo 13. One to go in my pocket protector, on massive job in a holster to hang from my belt. The leather holster is worth more than most calculators these days. Slide rules were serious business back in the old days.

    The Picketts are aluminum, but that was a considered a " new high tech" idea. Before that *Bamboo* was the considered the best material to make slide rules from. Used to have a bamboo K&E, and a circular Teledyne, but somebody with taste and no morals stole them.

  • I'm only 29, but I've used them before. Read on, and hear a tale of wonder and woe...

    When I was growing up, I had a set of encyclopedias that had been my mom's when she was growing up. It was called Our Wonderful World, and was published in 1953 or so. (If anyone knows where to get a set, leave a note -- my parents sold them...grr.) It was a great set of books, but the technology was pretty out of date. Between that and the old, old selection of books on science in the libraries of the towns I grew up in, I was forever frustrated that I couldn't find a Foobly67 vacuum tube to build a radio with.

    One of the things I read about was how to use a slide rule; that and all the slipstick references (paging Dr. Freud!) in Heinlein made me lust after one. But where the hell to get them?

    I ended making my own. Of course, I didn't know carpentry, so I made it from two strips of paper that I had carefully marked out on a sorta-logarithmic scale. It worked pretty well, considering that I guessed at where numbers like 3 and 5 should end up -- I was able to multiply 2 and 3 and come up with 6.3.

    This was in high school, and a math teacher saw me demonstrating how to use a slide rule to (vastly interested, I'm sure) friends. He took pity on me, and gave me a couple that he had from the dark days before cheap Taiwanese pocket-sized calculators. I also got a copy of the manual that came with one of them -- they were complicated things! -- and learned about how to do roots, cube roots, sines and cosines. I got relatively accomplished (relatively meaning that any competition was at least ten hours drive away), and used it to discover a wonderful proof of Fermat's last theorem; unfortunately, my pen wouldn't write on the plastic of the slide rule and so it was lost.

    I haven't got one now, but this makes me want to check out Ebay and get one. If Heinlein has taught me anything, it's "Keep It In The Family"^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H^H"Keep Your Slipstick Handy" -- you never know when civilization will collapse around you.

  • I had a professor in college who used to challenge students to contests doing calculations. He used a slide rule, and they could use whatever tool they wanted (they always used a calculator as far as I know).

    Now, I had never even seen, let alone used, a slide rule before. However, this guy's fingers would fly over that thing. I can't remember him ever losing while I was there, but he said that he had been bested a few times. The funniest thing was that he was usually done by the time the poor kid had found the ln button on the calculator...

  • Are American's today really so uneducated that they can't find the square root of 144, or the value of 2^10 without using a calculator?
    God, I hope not. I'm an American, and I sure as hell know how to do stuff like that in my head. Unfortunately, I know many people that probably could not. Hell, before July 4, a bunch of high school age kids were asked what the Fourth of July was celebrating, and they either didn't know, or thought that it was our independence from France...

  • by nagora ( 177841 ) on Saturday July 07, 2001 @10:47AM (#102142)
    I can go one better: I have a slide rule marked up for calculations in PRE-DECIMAL UK money. where 1 pound=240 pennies. It even does guineas!


  • by Gordonjcp ( 186804 ) on Saturday July 07, 2001 @07:58AM (#102146) Homepage
    Even the Navy and Coast Guard have ABANDONED teaching or using morse code. (Only old fossil ham radio exclusionary elitists praise it now).

    Perhaps in the US, they do not teach or use morse code. But it is still the a fantastically efficient way to communicate, in terms of power usage bandwidth.
    A very simple homebuilt transmitter can send an intelligible signal around the world, with an output power of perhaps 1 watt.
    Got no transmitter? Use a heliograph. Or bang a pipe. Flash your headlights, whatever...

  • by j_snare ( 220372 ) on Monday July 09, 2001 @05:25AM (#102155)
    I'm only a little older than you (21) and I have a slide rule. It was my mother's back when she was a physics major in colelge. I've even used it to take a physics exam in college. (I forgot my calculator.) I highly recommend that you find one and learn to use it. They are VERY easy to use, and very useful.

    Actually, pretty much the same case here, except I don't know how to use it. I got one from my father a couple of years ago and have been searching for directions since then. My father doesn't remember how to use it very well, and no one else I know seems to know how either. I'm still interested in learning how to use it, anyone know of a good set of directions somewhere? Or do any good books on this exist?
  • I still use my E6-B (manual one) rather than an electronic one or a GPS for figuring time/distance problems - it's just so much faster. Batteries never go dead either!

    I'm not some old timer either, I'm not even 30 yet and I've only been flying for 4 years. I do have a GPS (it's nice to have the HSI display when flying IFR), but a mechanical E6B is still a very useful tool. I upgraded from a cheap card one to a nice aluminium one too ;-)

  • ...Back in the years when it was still not cool to be a geek...

    CmdrTaco: Jon, I am sorry, your services are no longer required...
    JonKatz:What do you mean?
    CT: Geeks are cool now, it says so here. []
    JonKatz: I can still... complain about corporations and stuff, can't I?
    Michael:Sorry bro, that's my department now! HAHAHA!
    JonKatz:This is just yet another manifestation of the classic post-modern urge to bury one's head in the sand, don't you see?
    CT: (sighs slightly) Yes, that and MK-ULTRA manipulation, too, Jon...


  • I still have my slide rule from childhood... I got it because it looked cool and seemed pretty useful and I wanted to learn it. Pretty simple, and really neat actually.

    In mechanical drawing, you really learn how powerful not only slide rules, but normal, scaled (triangular) rulers can be. For example, to divide a distance into equal parts, just line up "0" with the beginning of the distance, then tilt the ruler down a ways. Make check marks at each centimeter/inch mark along the ruler's edge. Now take your T-square and triangle, line up the last mark with the end of your distance to establish your angle. Just slide your triangle over to each check mark and transpose that to your distance... Voila - evenly broken up along it's length into as many parts as you wanted... (It's easier to show this than explain it)

  • Although I'm not adept enough with my Pickett slide rule to rely on it entirely (especially in classes where 3 decimal precision is considered essential, and time is limited), there is one situation where I have found it quite useful - classes where a calculator is not allowed. Most teachers only make such a restriction to keep students from using built-in cheat functions on some calculators to skip difficult problems, and having my slide rule helps me to do the simple math that I am supposed to have learned by now. Plus it's great for impressing girls.
  • by Mumbly_Joe ( 302720 ) <> on Saturday July 07, 2001 @07:25AM (#102174)
    .. by private pilots!

    We use a tool called an E6B, invented originally (I think) by the army, which has a circular slide rule on one side of it.

    The circular slide rule is pre-marked with conversions that are interested to pilots, such as gallons/gas->pounds and gallons/oil->pounds, and it it frequently used (in flight, with one hand) for computing distance covered.

    There's a tons of other conversions, and of course, you can do any other mathematical operation that a slide rule can do.

    Aviators are the only people I know who still use these slide rules -- but every student pilot where I flew was issued one and had to use it for the examinations.

    Mumbly Joe

  • It might also be interesting, while conducting a dig for slide rules, to conduct a dig for the first time the subject of the archaeology of slide rules came up on Usenet. Should be early '80s net.misc, or so. There could be a whole taxonomy of wistful ruminations on the slipstick. The Well, CompuServe, in fact any BBS whose archives survive in paleontological context... would be kind of useless. dejanews was kind of useless, too. They don't go back far enough. I guess you'd have to start the "recorded history" of the net somewhere around 1990.

  • > 6/7 to three sig figs. Answer is immediate if the useful 7*11*13==1001 has been memorized. Actually, there's an easier way to figure out any fraction of 7 to as many places of accuracy as you want. It turns out that all fractions of 7 have the repeating pattern 142857. So to calculate, say, 6/7, you'd only need to calculate the first digit, 8, and follow the pattern: 6/7 = .857 142857 ...
  • I still miss the -analog flag to xcalc. Under the X window system, if you run "xclock -digital" you get a digital clock, while "xclock -analog" gives you an analog clock. The command "xcalc" gives you a calaculator. Long ago some sneaky individual programmed it so "xcalc -analog" would give you a working slide rule. This feature is not in current version, but I wish it would make a comeback.
  • I was introduced to the "spirit of the slide rule" by some works of Robert A. Heinlein, in which some characters had to do something or other with them slide rules. It seemed like a big deal. I was young, calculators were all over, and I wondered what the fuss was all about.

    Being a good writer, however, Heinlein finally managed somehow to get his point across, and I found that using a slide rule could give you a better uhmmm... let's say manipulation ability of the involved mathematical concepts. I even learnt to use an old one of my father, and loved the simplicity and power of the design. Somehow fascinating, but sorry no graphics display :o) So I kept with the HP. I remember going to math and physics exams with that 64K calculator filled up with all the theory, as text. I never had a teacher tech-savvy enough to know that calculators could carry full pages. That was a neat trick that slide rules still have to learn :o)


  • by s20451 ( 410424 ) on Saturday July 07, 2001 @08:23AM (#102186) Journal

    There's a great scene in Apollo 13 where a group at mission control frantically works with slide rules to calculate information before a computer on the ship is shut off.

    Yes, that was a cool scene from a cool movie. However, the calculation they were performing was addition (from Lovell's line to the effect of "check my addition"), and I'm told that this is something slide rules can't calculate.

  • by s20451 ( 410424 ) on Saturday July 07, 2001 @08:34AM (#102187) Journal

    There's this cool chapter in the book "Surely you're joking, Mr. Feynman" in which the Nobel-laureate physicist Richard Feynman describes how he could calculate all kinds of complicated expressions in his head, simply by being very familiar with log tables and basic arithmetic. Unfortunately, in the calculator age this skill has been lost.

    Example: Someone asks Feynman to calculate e to the power 3.3, and then to the 3:

    "I happened to know three numbers -- the logarithm of 10 to the base e ... which is 2.3026 (so I knew that e to the 2.3 is very close to 10), and ... I knew the log of 2 to the base e, which is .69315 (so I also knew that e to the 0.7 is nearly equal to 2). I also knew e (to the 1), which is 2.71828. The first number they gave me was e to the 3.3, which is e to the 2.3 -- ten -- times e, or 27.18. I knew I couldn't do another one; that was sheer luck. But then the guy said e to the 3, that's e to the 2.3 times e to the .7, or 10 times 2. So I knew it was 20.something, and when they were worrying how I did it, I adjusted for the .693."

    This is covered by fair use, I hope. But seriously - go get the book. It's an excellent read.

  • I love my TI-92+. How could you not love the most poweful calculator on the face of the planet? It's a graphing calculator and a book of integration tables all rolled into one, with the added advantage of being able to solve ordinary differential equations (symbollicly, even). A real life-saver when you've got a lot of partial differential equations to do in your homework. I've yet to see anything better on the market.

    However, different teachers have different policies about calculators. Some won't allow graphing calculators because they can store text (so can the old TI-68 scientific, but it doesn't look like a graphing calculator). Some will allow graphing calculators, but not ones the size of a VHS tape, complete with QWERTY keypad (even though the TI-89 has the same capabilities in a normal-looking design).

    I'm fine with these policies for the most part, but it begins to irk me when, say, they won't allow calculators that can store text, but will allow a crib sheet. Or they won't allow a calculator that can do symbollic integration, but they will allow a book of integration tables. These sound an awful lot like "I won't allow technoligical aids because I don't understnad them."

    When I find I have a particularly anal-retentive teacher, having my father's old sliderule handy is greaty for making a loud statement without saying a word, sticking out like a sore thumb in a room full of people pushing buttons. As long as you don't have notes written on it or anything, there's nothing they can say about you using it.

    As for figuring out how to use it, my father had a pair of small books on their use, one of which was a book my grandfather got from the War Department while he was in the Navy. They're not hard to learn (easier to learn than most scientific calculators if you already know a thing or two about logarithms, as there's no different button layouts to get used to or Reverse Polish Notation), and I find they also help reinforce ideas about logarithms (you can SEE why log(a*b) = log(a) + log(b)).

    While I'm not a rabid collecter with 300 sliderules (what a freak... now if he collected calculators... :) ), I'm glad I've got mine.

  • by Registered Coward v2 ( 447531 ) on Saturday July 07, 2001 @07:26AM (#102194)
    The real beauty of using a sliderule was that you developed a feel for the numbers and what the results should be. After you had some experience estimating magnitude, if someone came up with some calculations, they'd either feel right or you'd get a gut feeling that something is wrong. I am still amazed that people can multiple two three digit numbers in the form of x.xx and y.yy) and come up with zz.zzzz or however many places their calculator displays. Or misplace a decimal point and not realize the result is wrong. People assume because the work has been done by a bunch of electrons that it must be right.

    While I would not want to go back to only using a sliderule, the one thing that I did learn was how to estimate results in my head - a tool that has been very useful over the years.

    Spreadsheets and handheld calculators are great - you can do more more quickly than you ever could with a slide rule.
    You can also make bigger mistakes more often.
  • One of my favorite pastimes at sea was celestial navigation. I found a lot of satisfaction in shooting the stars and getting a nice position fix. Part of the fun was knowing that I practicing a centuries old art much the same as the earliest navigators. (Although I must admit I also enjoyed knowing my fix would be used to reset the multi-million dollar ships inertial navigation system.)
    That, to me, was what set sailors apart from everyone else: no matter where you were, or what side of the cold war you were on, you shared a long heritage and a common mistress - the sea. Even nominal enemies could share beers, swap lies and toast those on permanent patrol. It was why, when the Glomar Explorer raised a Russian nuke we buried, at sea with honors, those we found inside.

    Somewhere Megellan and Vasco da Gama must be smiling.
  • by SilentChris ( 452960 ) on Saturday July 07, 2001 @07:16AM (#102198) Homepage
    There's a great scene in Apollo 13 where a group at mission control frantically works with slide rules to calculate information before a computer on the ship is shut off. Going down the row seeing them raise their thumbs and say "checks out, flight" is one of the better scenes in the movie.
  • I found this site months ago and find it to be a useful tool in TEACHING slide rule use. html

"The Avis WIZARD decides if you get to drive a car. Your head won't touch the pillow of a Sheraton unless their computer says it's okay." -- Arthur Miller