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Know How To Use a Slide Rule?
high_rolla writes "How many of you have actually used a slide rule? The slide rule was a simple yet powerful and important tool for engineers and scientists before the days of calculators (let alone PCs). In fact, several people I know still prefer to use them. In the interest of preserving this icon we have created a virtual slide rule for you to play with." Wikipedia lists seven other online simulations.
at around 10 years old. I've been using it ever since, and don't plan on ever stopping.
At least a slide rule is more accurate than excel 2007.
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I prefer to use a tactical nuclear slide rule, myself.
I did college physics, organic and physical chemistry with my trusty Pickett aluminum log-log slide rule. You needed one for real geek cred in those days.
Some mornings it's hardly worth chewing through the restraints to get out of bed.
When I took HS Chemistry a slide rule was required. The instructor spent a bit of time explaining how to use it and we were quizzed later. While it lacked the precession of modern calculators we managed to solve complex problems. My dad earned an engineering degree back in the 50's using only a slide rule.
In case you'd like to work with the real thing, take a look here for some info on places to buy slide rules these days.
My mother recently bought one in a wave of nostalgia. I can certainly understand the physical appeal - the soft susurration of the pieces gliding against each other, the comforting grip of the leather carrying case, the art of perfectly lining up the dashes to the limits of human precision. If computers were that tactilely slick, nerds might rule the world.
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You youngsters and your simpleton slide rules. Try a real one that makes you use that noggin of yours. http://home.earthlink.net/~apendragn/runish/sliderule/index.html
There's a reason we don't use slide rules, abacuses, buggy whips, etc. - we have better tools now. I used to have one when I was a kid back in the '80s, never really figured out what it was for, especially since we had scientific calculators instead.
The only slide rule around here is to not push the kid in front of you.
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I also don't know how to use a Flintlock rifle, trap/clean/spit roast a hare, catch a fish with my bare hands, hitch a wagon to a horse, or build/make/use a butter churn.
Since I live in the 21st century, I don't really lose sleep over those things.
I've never had one required (courses tended to require graphing calculators by the time I got to them), but I found one in my grandpa's desk and learned to use it. Then I carried it with me to high school and gave it to anyone who asked to borrow my calculator.
'Sensible' is a curse word.
I grew up after hand-held calculators were ubiquitous, and after slide rules were rare. However, it was also before calculators were allowed on exams, but slide rules were! So, I learned how to use a slide rule. Later on, I was allowed to use a slide rule with all my useful chemistry and physics equations written on it, even though programmable calculators were forbidden b/c they might have formulas stored in them.
the bigger the slide rule, the more accurate the calculation...
"The index line on scale C is always put over the number to be multiplied on scale D"
What's the point of explaining how it works if you don't explain what each of the terms used is?
Damn nerds...
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but in reality, justifying precision more than 4 significant places is really difficult using proper scientific/engineering methods. For instance 4 decimal places in surveying takes you to an inch range even over a mile of distance with hand tools. Average slide rules can do 2-3 fancy ones can hit that last place.
I use a slide rule DAILY. It's an extremely useful and (if you know what you are doing) both accurate and fast. For many engineering problems 3 or 4 sig. figs. is plenty enough. The advantages are well-known - the most important being the elimination of "false precision" that you can get with a mindless calculation with a 10-sig-fig calculator.
They are also just good things to have around. A good slide rule (Aristo, Nestler, Faber-Castell, etc) is just such a fantastically well-made device that you really need to see it to appreciate. The precision is something you don't see these days. Even a lowly Pickett is nicely made.
Brett
What is the point of having such a long rule, if you only see a part of it and cannot move both parts at the same time???????
At least, this one is usable:
http://www.antiquark.com/sliderule/sim/n909es/virtual-n909-es.html
For engineering, you're right. For other sciences: well, let's just say that you wouldn't want to have to calculate an Earth-Mars transfer orbit with a slide rule.
When my grandad died, he left his "old" slide rules to my dad and me. My dad kept the original wood and cellulose one from the 1940s; I got the plastic one from the 1960s / 70s.
I soon got the hang of using it (and it can be quicker than a calculator sometimes), but I knew the general principle from before anyway. The main thing you have to remember is the slide rule only ever gives you the mantissa; you have to work out the exponent yourself. This means you have to do a rough mental calculation. People often put too much trust in calculators. When I was filling in order forms by hand in a previous job, I never used a calculator -- and I never got called out on a wrong total.
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The E6-B is a rotary slide rule that pilots use for calculating wind correction angles, time/speed/distance problems, conversion between units (i.e. weight of a certain number of gallons of fuel), and fuel consumption.
It's preferred over digital devices because they still work when the batteries go flat, they are easy to use with one hand, and some models are actually smaller.
http://en.wikipedia.org/wiki/E6B
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Slide rules are still in active use by - of all people - snipers. The Mildot Master is a sliderule for determining distances and ballistics for long-range precision shooting when using a rifle scope fitted with a "mildot reticle".
Simple, low-tech, durable and cheap - specialized slide rules are still useful for particular applications where computers are expensive & fragile overkill.
Can we get a "-1 Wrong" moderation option?
For some reason, I'm hearing banjo music...
I did not need that visual.
Ben Hocking
Need a professional organizer?
but with a slide rule you can see a range of answers around the result for varying the factors. that process is extremely slow on a digital calculator. plus a slide rule forces you to think of the proper magnitude of the answer, with calculator people trust without thinking and "missed decimal point" or just fat-finger error gets believed more readily.
A whole lot of engineers calculated a lot of transfer orbits (not just Earth-Mars) with slide rules. In some ways they can be a lot safer than using a calculator, since they don't give you a false sense of precision.
E.g., divide 52 by 7 on a calculator, and it will spit out 7.428571428571, a completely correct although ridiculous answer when dealing with real-world quantities, since it blows away the precision of the input numbers. Slide rules require you to constantly consider the number of decimal places that you want, and encourage you to only write down the correct number of digits (so you might do the same result and put down 7.4).
Personally, I think some of the best engineering ever accomplished by man has been conducted mostly by slide rules. I wouldn't go so far as to say that we've necessarily regressed since then -- computers are great, don't get me wrong -- but it's not right to simply write off slide rules. They had very distinct benefits and I think students would be well suited if they were kept around as a pedagogical tool.
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The thing about a slide-rule is it makes you think about the answers, so your less likely to forget to convert the acceleration of your ship, from furlongs per fortnight squared to meters per second ^2, like a certain space agency did a while back when they assumed the math was correct because the numbers came out of a computer. Slide ruler have an inherent requirment for the operator to do sanity checking, using a calculator or a computer usually means the operator doesn't even realize when the wrong keys produced outrageous results.
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If anyone is interested, here are several links to downloadable ebooks and manuals for using slide rules:
My only experience with using a slide rule was back in the 1960s in an 8th grade math class where we spent two weeks learning to use slide rules. We were just 8th graders, but were able to use a few basic features of something that was normally used mostly by scientists and engineers. Mr. Turner, our math instructor, even wore a small slide rule as a tie clasp. I suspect that the use of slide rules was something that probably was not normally taught to 8th graders.
Later on in Junior College, I once thought about possibly taking a 1 credit slide rule class, but didn't. That was in the days back before pocket calculators. In the College Algebra class our textbook had Log tables, a square root table and various other tables in the appendixes in the back which we used to get answers without a pocket calculator (or a slide rule).
I still have my dad's old Ivory and wood slide rule that he bought back in the 1950s and also a more modern plastic slide rule which I later purchased. I am plan to briefly brush up on how to use them just for the heck of it.
A slide rule gets you 3-4 digits faster than a calculator. You have to know how to use it.
I was in the last class in my high school that learned how to use a slide rule. I was in the first class in my college where owning a scientific calculator was required for entry.
As a freshman my Econ professor asked the class if anyone with a calculator would do a division for him. I was carrying an inexpensive plastic slide rule in my back pack. I did the division and said the answer. As he turned to thank me he did a double take and said "What is this?" taking the slide rule from me and holding it up. I said "Its new, a solar powered calculator that never needs batteries." "What will they think of next?" he pretended to marvel.
The point of that whole story is that about 15 people probably had pulled out a calculator and started to do the division and I was able to beat all of them by several seconds.
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You ever take a calculator apart? They are way more complicated inside.
What's sad is a good 4 function calculator costs 1/10th a slide rule does.
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At the university I attended, freshmen engineering in 1973-74 required the use of a slide rule. In the 74-75 year, you could take freshmen engineering with either a "slip-stick" or a calculator. My freshmen year, fall of '75, required a pocket calculator. I was facile with a slide from from high school chemistry and physics, and can still do the basics, but haven't used one since. So the transition from slide rule to calculator was very fast.
A slide rule enforces estimating a reasonable answer before hand, and encourges arranging computations for economy of calculation. I think there is a big benefit to critical thinking skills in praticing basic computation with a slide rule.
That said, computers have made it possible to do what was formerly impossible due to computational expense. Integrated circuits would not be where they are if you couldn't burn many flops running spice. Cars would weigh more and get less gas mileage without mechanical simulations because they would have to be over-built in order to simplify strength calculations. Pre-computer-simulation camera optics suck when compared to modern computer optimized lens, ditto for antennas.
I once met a guy whose mother was a computer.... that was her job title: "computer". She worked for a university research department, where row upon row of "computers", mostly women, sat in front of mechanical calculators all day long, 40 hours per week, cranking through tablets of computations for various numerical models. Modern electronic computers enable solutions to problems there were too expensive to attack before, and life *is* better as a result.
And when your computer crashes due to hard drive problems, power supply blows up, motherboard fries, etc, etc, etc, then what? "oh, sorry Professor, the computer is dead and I can't do that bigass math problem until the computer is fixed. Can you get the trolls in IT to hurry up and fix it?"
Are there really people who read Slashdot who can't see the pleasure in learning something new, nor can they see the potential benefit in learning how to use something like the sliderule?
I can't imagine how intellectually pathetic they must be.
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Ebay. Search for "Pickett slide rule"
Grab a Microline 120 or 140 for about US$10.00.
Yes, it's plastic, but it's a damn fine slipstick for a beginner, and there's several "How to use a Slide Rule" books on the Gutenberg site.
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...my grandpa just gave me the slide rule he used in school and it has a genuine "Made in Occupied Japan" sticker on the case. I can't remember the brand or model, but it's in a nice case and really is a beautiful thing. It is machined which is, according to the manual, much better than the painted ones. Just my two cents...
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I'm a young'n, being in my mid 20s.
Dad was an engineer. I learned how to use a slide rule for basic math in first grade, just because "it was neat" -- after all, if dad the engineer uses one, it must be cool.
One of my math classes "required" a TI-82 (Jr. High), since some of the problems were of the "push these buttons in this order to graph this equation" type. After that, most kids went out and bought the latest and greatest TI graphing calculators. I was given a TI-86 when they were first released, as "the calculator that will do anything you need it to through college" by my parents. It was neat for a while, some of the games were cool, and programming in assembly for it was kinda fun - at least much more so than paying attention in Early American Literature. But I didn't use it for my math classes. I was the nerd in the back of the room using dad's old slide rule while everyone else was punching buttons on their calculators.
I continued using a slide rule for most problems until my senior year in college, when I switched over to a TI-89 because I was extremely lazy and it made the statistics class much easier (it did all the work anywhere where we weren't required to "show our work").
I still have it, and still use it out in the shop on occasion. My TI-86, TI-89, and HP-48G+ sit gathering dust.
Everyone in my school had to learn to use a slide rule.
The main thing I notice about slide rules versus calculators, is that in many computations, the user is required to be aware of certain techniques, often involving logarithmic properties. And in many calculations, you see a *range* around a solution, not just a number popping up like on a calculator.
Slide rule users tend to have a natural ability to estimate the magnitude of a solution, and do not find sigfigs and scientific notation (with a single digit mantissa) to be an unusual idea.
One nonobvious consequence of electronic calculators has been to push the understanding of log properties from early grade school arithmetic, into at least middle school territory, and I know for a fact that many College Algebra students today have difficulty with logarithms. In the slide rule era, there was *no way* a student would get out of grade school math without naturally being very comfortable with logarithms, and how to relate multiplcation to the sum of logs.
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Circular slide rules were very popular with pilots because of their compactness. Some of them had specially marked scales for doing Time, Speed, and Distance problems.
I did the same thing with my HP-48 because my slide rules were too precious to risk in the hands of others.
Student: "May I borrow your calculator?"
Me: "Sure. Here."
Student searches in vain for any operational familiarity.
Student: "Ummm, no thanks."