This brought back some fond memories. In my Junior year of high school (1975), I got the high score on a competitive math exam. (I even beat the seniors!) The prize was a beautiful aluminum Pickett slide rule that had a set of double-logarithmic scales in addition to the standard scales. The following year, everybody else was using TI-30 calculators, but I used that slide rule all through my senior year and even into my beginning college years. I still have it, along with its leather case and belt-strap. I actually pulled it out while I was watching this video and did the square root calculations with you. Thank you so much for this video.

"I'd thank my dad, if he were still around." my feels: 😭♥️

I still have the slide rule that I got from a very old gentleman that was a friend of my mom. I got it for mowing his lawn. I was 14 at the time (now approaching 65) and he taught me how to use it. I used it all through high school and many years later in college. I still keep it in it's original leather case. Mine is a Dietzgen Trig Log Log rule

I love slide rules! My grandmother gave me my grandfather's slide rule shortly after he died. He had apparently always intended to give me one, but by the time I was ready, calculators were a thing. I proudly carried it in my backpack in college, and even found an excuse to pull it out during an exam when my calculator's battery "died". I put a note on my paper to the effect of, "Forgive slight inaccuracies - last few answers done on a slide rule." :D Great video. We'll see if the price of slide rules on eBay goes up because of this!

When I saw Hidden Figures I was sitting there thinking "Where the hell are the slide rules?" The engineers and the women who did computations prior to the advent of computers should have had slide rules, but there were NONE in sight.

I've just learned that a slide rule can also be used to solve factorable quadratic equations. That is, if x^2+ax+b has real roots, r1 * r2 = b, and r1 + r2 = a. Since C against D is a constant ratio, CI against D is a constant product. After setting the slide such that CI*D = b (above), visually slide along the rule until you find the combination of CI and D to satisfy the "a" coefficient. I've seen several sets of instructions for slide rules, but only one of them had this procedure. One slide to rule them all, and in the darkness bind them.

Pilots still learn to use slide-rules in the form of the E6B. It's interesting because it is circular (which works well due to the way logarithms work. You can see simplified versions on some aviator watches too.

I watched this when it came out and couldn’t understand it. I also was sleeping an average of 2 hours a night, I had really severe insomnia for almost 2 years. Watching it now I totally get it, it seems simple even. Little things like this make it evident how cognitively impaired not sleeping made me. I still have memory problems, fatigue, and some other random issues… sleep is precious, y’all.

WOW!!!! THANK YOU, VERY MUCH, FRAN, FOR THIS INFORMATIVE VIDEO, ON SOME OF THE AMAZING CAPABILITIES, OF THES DEVICES!!! I REMEMBER WHEN MY DAD, (a "DRAFTSMAN"), FIRST GOT A TEXAS INSTRUMENTS "TI-30" HAND-HELD CALCULATOR", BACK IN THE EARLY/MID 1970'S... I WAS, AND STILL AM FASCINATED BY THE MECHANICAL "SLIDE RULES"!!!! I REMEMBER LOVING TO FIND A VARIETY OF "NOMOGRAPHS" USED FOR A VARIETY OF SPECIFIC PURPOSES, SUCH AS "MECHANICAL SPRING" PROPERTIES, WEIGHT/VOLUMES/PRESSURES,... METAL ALLOY PROPERTIES... SOIL PROPERTIES, ELECTRONICS COMPONENT PROPERTIES, MOTOR SIZES/TORQUES/VOLTS/AMPS, WIRE SIZES, ETC.... WHERE CAN WE FING "SLIDE RULES?!... i'D LIKE TO GET ONE FOR USE IN WORKING ON MODEL AVIATION" RELATED HOBBY DESIGNING...

THANK YOU. After 46 years, the slide rule is simple and amazing. WHY didn't they teach this in highschool math class? I never heard about slide rule in public school and after being introduced to calculators, there was no incentive to investigate the slide rule. Even weirder, my dad was a highschool teacher and a principal.

I had a slip-stick back in high school when I took a class in business machines. I even used a card punch machine. I can still hear the instructor telling us it was going to be the job of the future. About the time I moved on to my senior year pocket calculators hit the scene and that was the end of my slide rule days.

My first Engineering class in college back in 1974 required us to use the Slide Rule for all computations. After that class, electronic calculators were permitted. My slide rule belonged to my father, a telephone company traffic engineer, and it was a bamboo Keuffel & Esser (K&E) brand. It came in a very heavy duty leather carrying case. For my first Electronic Calculator, also in 1974, I purchased a Texas Instruments (TI) model SR-10 for $110. It was called an “Electronic Slide Rule” although my father’s slide rule could actually perform more functions and it did not have batteries that needed to be charged. Fran, thanks 😊 so much for this video. It brought back many fond memories of my father and his awesome bamboo K&E slide rule. I’ll have to go looking for that slide rule today so I can ask my 9 grandkids and 2 great-grandkids if they might know what this cool 😎 contraption is used for. LOL 😂! Cheers! Dave

What a beautiful slide rule! Your Dad must have spent a lot for it back in the day. When Canada went metric, the gas station that I worked at gave away cardboard slide-rules for converting MPG to L/100 Km. Fuel consumption was important in the 70s! We also had stickers that people put on their speedometers to convert MPH to KPH (it would have been a bit awkward using a slide rule converter while driving!)

I've been running through a physics textbook from 1939 with just a slide rule, then checking the math with a calculator you'd be surprised at how accurate they are especially when you account for sigfigs

In 1959 my first subscription to Hot Rod magazine came with a cardboard slide rule set up for all kinds of car things, like matching the bore & stroke of an engine to show it's cubic inches. My father, an Air Force pilot at that time, had a circular one for pre-electronics plotting where they were and figuring out other data needed.

I still have the slide rule I purchased back in high school in the late 60's. Only slide rules were allowed in exams at university in the early 70's. Your video takes me back in time. Also reminds me of using log tables as well as the slide rule. For complicated calculations finding the decimal place was sometimes time consuming. Dave.

Yes they are, I remember back during my Jr. year in high school 1993, asking my electronics teacher to teach me how to use one... Which he did and he even gave me one. He was shocked because I was probably the only student he had in the 90’s with any interest in them....

That reminded me I have to "D scale" my coffee machine.

The Franlab jam at the end is badass

I still have the one I got in school in the 70s. Requires no battery, perfect for the zombie apocalypse. (And, I have a TI-30 calculator too!)

A bit behind, working through a backlog of videos but... I saw this and lit up. I may be (relatively) young, but one thing my grandfather taught me years ago was to use a sliderule. I ended up with two of his slide rules - a Hemi 257 and a Hemi 259D. Both are really nice and have some neat features, like squares, roots, multiplication and division, etc... Sometimes, in this world of modern tech, it's just nice to use something physical. Especially when you need to consider significant digits. More decimal points doesn't always mean a more accurate calculation - your calculation should only be as good as your measurements.

Great - I still give them to my physics students with some instructions and let them play for a while as a way of thinking out of the box, understanding numbers and their relationships better and just a bit of fun. They seem to enjoy it!

I learned to use one during high school honors chemistry in fall of 1962. That was on a cheap plastic one. Two years later I got a nifty Dietzgen before heading off to college. Years later, I got well acquainted with the circular version in the form of the Jeppesen E6B flight computer. I still have all three. You mentioned the accuracy of the slide rule. My chemistry and engineering teachers stressed that no computation can be any more precise than the least precise measurement involved in the calculation.

YES! Slide rules are STILL amazing, My "daily driver" had an aluminum frame and slide, but the really smooth ones used bamboo. I had a bit of a collection, donated by my engineering compatriots as they went "full calculator"; sadly, all were lost in a fire in the mid-1990's. There were odd shape or purpose slide rules, as you show, and it would be difficult to find some of them these days. When I took engineering, you could always pick us out by the belt scabbards for the slide rules - some 20-24 inches long. As much as I find my modern calculator very helpful, I miss the slide rule for some jobs.

Thanks. I remember an electronics teacher in 1995 being sad for people who never learnt to use slide rules, commenting that those people never learned to actually think about the true accuracy of the calculations they made based on some measured values - as calculators just pour out that screenful of digits. I'm also too young to have actually learnt to use one, but have acquired a cuople along the way and played with them enough to do the base maths (multiplication and division), but this video was a very good demonstration on what all else these things can be capable of.

I still have my slide made by Post. Plastic case and real glass. My algebra teacher gave it to me when I graduated high school. He even autographed the case for me.

I ran across my old slide rule a while back in a time machine junk drawer. I actually used it in my early college days, circa early 70s, about the time when Texas Instruments and Hewlett-Packard started out with their calculators. I couldn't come even close to affording the early calculators so had to make do with my slide rule. Just for fun, I figured out (sorta remembered) how to do simple multiplication. In the same drawer was my "super fancy" HP calculator I used in the late 80s. It has this magnetic strip reader thing. One could use good old Reverse Polish Notation to write simple-ish programs and zip the mag strip into the reader to load the program into the calculator memory. Wash, rinse, and repeat. Pretty cool back in the day.

This reminds me of when one of my professors showd us a slide rule in a tutorial meeting, just for the fun of it. He tried to show how easy it was but us "children of the pocket calculator" was left a bit fuddled. I too had my first pocket calculator in 1976, comlete with red LED numbers.

Yay! Slide rules :-) As a youth I'd watch old science fiction movies where the hero scientist would whip out the slide rule. I was sad that I couldn't afford to get one....fast forward a errrrr few years, I have lots of them, and they are still cool :-)

I still have my Faber Castell Rietz 111/87 which is a slide rule for machine and electronics engineering. It is really handy tool for estimating and eyeballing things. I like it.

I use a Castell 67/87 RB with an Addiator, a great tool to have near by

I have always wanted to know how to use a slide rule. I remember seeing them in old movies and thinking how cool and smart they make you look. I’m definitely going to get one. Thank you so much Fran!!! Love you!

I got through high school with a slide rule Slide rules are all about estimating Problem now is that students cannot estimate what a reasonable result should be Thanks for showing various types of slide rules This is a gigantic deal No joke Huge, gigantic, intergalactic, or bigger

Oh that is so nostalgic. I still have my Faber Castell slide rule that my Dad bought for engineering college and taught me to use. The ubiquitous green box is witness to the years of use and abuse. He had the same model that he used throughout his work life in aircraft design. It took me through my technical college and apprenticeship. Calculators were creeping towards the end of my college time but they were not as quick as a slide rule. Thanks for showing this Fran.

There are also caclulating discs for multiple purposes. For instance the geman Kriegsmarine used an Attack Disc to calculate things like interception courses, attack courses, predictions on a target, angle of bow etc. I built one of these and used it to play silent hunter III and it always worked pretty well.

I think we're about the same age. I got my first calculator in 1975, a Rockwell / Anita 30R "Slide Rule Memory" model which was branded House Of Fraser in the UK. But we were still taught how to use slide rules in secondary school so I bought a 6" model which was branded "WHSmith Simplified Rietz" made by Blundell, probably around 1977. Not that I can remember how to use it any more.

We used slide rules in high school. I went to West Catholic on 49th & Chestnut, way back in the stone ages. In grade school, we had to do all calculations on paper ...and show all work. Fun times. Cool video. Thank you for sharing!

Just before covid I hung a 6 ft. training slide rule in my shop classroom. Several students thought it was very cool. They went on line and bought them. Then watched KZfaq to learn how to use it. The thought it was so much fun to use them in math class because none of the teachers had ever seen one and did not what they were! I used mine back in the 60's.

Still have mine from college back in the early 70's; a Pickett 880.

I worked for a Land Surveyor during High School (mid 60's). At that time the Crew Chief carried around a small book of trig tables for doing computations in the field. I guess things needed to be more accurate than 3 places. But in the 80's I took flight training and you had to learn how to use a circular slide rule for navigation. I'm sure I still have my slide rules from school. Neat Stuff!

great memories. I wonder how many of us inherited slide rules from our Dads. thank you for the video... again

1:08 That slide rule looks remarkably like the one I used throughout my college and university years, and well into my early engineering career; a Faber-Castell 1/98 Electro, if memory serves me well. It is in my desk now, having outlived many newfangled calculators, and it needs no batteries!

I paused this video and grabbed my slide rule to follow along with the video. Your collection of purposeful rules was really interesting.

I've got a collection of almost a dozen really old slide rules, including a 7 foot long Pickett handing on my living room wall. hah! One thing I noticed almost immediately after I started learning how to use a slide rule, was that the more you understood the slide rule, the more you didn't need to use it at all. My intuition of the "patterns" of numbers grew immensely almost overnight. We should continue to teach them in schools for this purpose!

I still have my slide-rules from vocational High School here in San Francisco in the 60's. I finally got a vintage super quality Pickett bamboo unit. I like Fran.

Enjoyed this one Fran, started collage in 67 with the slide rule and the log table books added a four function calculator (red LED display) in 72 as I finished. The slide rule didn't need batteries, but beer did effect the slide rule for some reason.

I got a slide rule from a colleague back in 2005, I started working as an engineer, and i used it to do calculations..i sort off grew fond of these so i started designing them myself for machining calculations, and not to long ago i made a barrel shaped one that could fit in your pocket...

Started with log tables, moved to a sliderule, progressed to a better sliderule. I seem to remember 2 decimal places was achievable in most cases. I then bought a Sinclair calculator, cost a king's ransom to buy and another to keep in batteries. Then one of my lecturers who was a real wheeler dealer turned up with a huge case of scientific calculators (with power units). They were all gone that morning. That same year there was a flood of calc makes and models, watches and all the trimmings and suddenly they were no longer "special". I still took my sliderule into exams, just because they didn't need batteries. But nostalgia and the visibility of a sliderule soon gave way to the pocketability of a calculator.

My bachelors is in electrical engineering. That was in the 80s and, of the many classes, one that I remember well is a professor showing us how to use a slide rule just for fun.

I still have my Pickett N1010SL-ES Super Power Trig slide rule from my college days.

My dad has a Sun Hemmi bamboo slide rule he got for college that is a chemical engineer's model--one side has regular slide-rule scales similar to yours, but instead of more advanced mathematical functions, the scales on the back are all about things like molecular weights of various materials and density and pressure conversions. It has a sort of leather scabbard. Nice-looking except the glass of the cursor has a big crack in it. I was also *just* barely too young to ever really learn to use one. Around 1976 or '77, he bought an Omron scientific calculator (its model number was 86SR which I think actually stood for "slide rule"), one of the first affordable models with trig and hyperbolic functions and such, and it impressed him enough that he got me one. So I had that from an early age.

A few years ago I gave my son the Pickett 1010 I used when I was in the Marine Corps over half a century ago. Your video brought back memories from long ago. I can say that all of my favorite memories are of the past.😱😁

Excellent ..... !! I used slide rules here in the UK right through school 1969 to 75 but we still weren't allowed to use them in exams. My best friend's father spent a year teaching in California and brought back the first digital calculator we'd ever seen, probably in 1973/4. In a drawing office for a huge civil engineering project that I visited with my father the draughtmen were still using a lever operated calculating engine set on a desk at the front of the drawing office at about that time also. As an aside, at my Junior school I used to walk past Merchiston Tower in Edinburgh twice a day, where John Napier, the 8th Laird and the inventor of Logarithms was born .... we were shown "Napier's Bones" as a tool for learning learning multiplication.

Yes, I was using a slide rule at Uni in the 60's. Still have my old slide rule from back then. Also carry my old E6B when flying which is a circular slide rule for navigation and many other calcs (eg. conversions).

When I was taking ground school for my private pilot license (1979) we had to use a slide ruler also but the functions where different. The version I used was called E6B flight computer. They still make them and lots of private pilot carry one. Think ground schools still cover there use in a 1/2 day of extra training

I have a lovely collection of slide rules. Sadly, almost no one but me even knows what they are let alone appreciate them 🥴

I still have my K+E Deci-Lon from high school/college days! Plus the six-inch K+E "pocket" rule that has the same scales. I have a circular Pickett rule which I didn't use very much because the "folded" scales were hard to locate where the result was! I still use it occasionally just to stay "proficient" with it. Amazing devices. And, no batteries required. But, a little difficult to use when the lights go out!

I had a three sided one when I was a kid. Had other weird computery promo items my Pa gave me. Most he got at at computer/data possessing conferences in the late 1960's. He also brought home Lindy's cheesecake on occasion . Good Times

The cursor comes into it's own when you do a string of calculations one after the other.

It is just so hard to get a good sliderule these days. I still have an old half broken sliderule in my desk, because it has an amazing compound interest scale. For practical stuff I mostly switched to nomographs, because I can print those with a normal printer in case I need special conversion. While I never formally learned to use a sliderule (excluding a nonius like on the calipers) our university lab still gave out printed nomographs especially on the microwave side. Like converting from 50Ohm to 75Ohm base, or converting from resistances to reflections.

I remember using one in my 1970 elecrronics tech class. It worked well with scientific notation working with large and small numbers to calculate tuned RLC circuit etc

You ever get used to using one they can be fun. Back when I was teaching Firemen about fire pump operation, we had a slide rule to determine fire streams. Found it the other day and, still remember how to use it. Could have used that one you have from SHURE back when I was setting up sound systems for shows.

My Dad was a Technical Illustrator and I always wondered how slide rules worked... great topic.

Calculators were just coming in while I was a teenager (my dad had one, with a red display, and clicky buttons), but they weren't allowed at school, so our school work did cover slide rules and their uses. Mum and dad bought me a rotary one, which I thought was quite cool - and no-one else at in my class had one!

Still have my K&E log log, or whatever it was, from my high school and college days. My father was an engineer (MS MIT) for the phone company and by proper reduction and manipulation could calculate a ridiculous number of decimal places. Of course he carried a slide rule on him at all times, and the family joke was that he was such an engineer that if our mother asked him what 2x2 was, he would whip out his faithful "slipstick" and in a flurry of baby powder (talc enhances the slipperiness) would announce "2 x 2 is 3.9999, oh hell, call it four."

Thanks for the demo. And thanks for this little touch : checking SR results with a classic TI-30 ; precisely the first scientific calculator model cheap enough to kill the SR.

When I was in the Air Force in 1985, during my training as a imagery interpreter specialist (imagery intelligence stuff), we did our photogrammetry calculations using a slide rule. In fact, we had a separate class to teach us how to do the same calculations on a pocket calculator. Their logic was, "in the field, if your calculator battery dies, you'd be out of luck if you don't know 'slip stick'." I still have mine, along with the accompanying log tables. Good times!

Dad had a slide rule that was circular. It's around here somewhere I'll find it when I'm looking for something else. After he retired from Westinghouse in 1971 he really embraced the pocket calculator.

Fran I have been collecting slide rules since I graduated from University in 1976. But your video has taught me more about how to use them than ever before. Thanks!! I think I have about 25 of them of all sizes. And yes no batteries are required and sometimes they actually are faster than slide rules and you can also see a range much easier than a calculator. Very few people use slide rules today and they simply don't understand their advantages.

The true secret of the slide rule is scientific notation. Converting everything to a number between one and ten, with an exponent. Along with the simple number, exponents are added or subtracted. Very large or very small numbers are easily dealt with. Perfect for electronics.

Learned the slide rule in 10th grade Chem class....1974. Years later I'm a teacher at my old school and strolling through the hallways in the summer and happen to see the teacher's demonstrator slide rule sticking out of a garbage can... A 6ft yellow Pickett slide rule! I fish it out if the garbage and hide it in my classroom's darkroom. The rule now lives in my woodshop at home. flic.kr/p/QZtYMS No pocket for your TI-30? Mine came with a faux denim belt-mounted zipper bag.

I was taught how to use a slide rule in high school, electronics 1 & 2, years 1972 to 1974. The teacher was fantastic. Taught us scientific notation along with the slide rule. Best years of high school was in that class. Learned alot from that man. Thanks Fran.

I just discovered your channels, and I'm really happy to see this video. I went to college for electronics in 1974 and part of the curriculum was a slide rule course. Those students who were Vietnam Vets were the only students allowed to have calculators, because a basic 4 function calculator cost over $100, and the Vets - with the GI Bill - were the only ones who could afford it.

I was in the last cadre of high school students in Australia (circa 1975) who were taught the slide rule in Mathematics class...Faber Castell studio, I recall. Learning to fly, I used a Jeppersen Computer, circular slide rule for navigation and performance calculations. Now I have a collection of some 40 slide rules, which I use whenever opportunity arises. I joy in my "new-in-box" FC 2/83 N and its little brother 62/83 N Novo Duplex (doncha love the names of these beautiful instruments), as well as a selection of Pickets, KE, Fish, etc. Some years ago, my teacher-librarian wife arranged for me to teach classes to Primary School students in her school, for which I equipped a set of Aristo student slide rules and made up some teaching plans (on Powerpoint, forgive me!). Now I make it a point when traveling to keep in my pocket a tiny 5" Sun Hemmi which I can whip out when a calculation is needed; smart phone, nah! Paired with my favorite fountain pen, I am able to embarrass my adult children with Grandpa's mathematical sophistication. Wonderful video series, Fran.

I love this! I do remember a time when give-away scales like that were very common. I don't think I kept many of them; I think I regret that. It would be interesting to go over the mathematics of some of the scales of some of the give-away scales, like the electrical or the radio ones. Mostly just "X is proportional to the square of Y" kind of thing, but it's interesting to look at the analytical calculation as compared to the physical scale. Great video! Love it!

I went to school in the 90s and I always had calculators at my disposal. For fun I decided to use an old HP engineering calculator with reverse polish notation for school and I also found someone to teach me the slide rule. Much more fun than the dumb calculators where you don’t even need to now the order of operations.

They have slide rules for music to determine keys and things. Kind of similar.

It is truly a wonderful World with bright people like you

I bought a slide rule at a flea market because, as a kid, I thought slide rules were always a mysterious tool used by very smart people. I'm glad I bought it to study this mysterious tool and it was good to see your video and allay the fears I had about slide rules.

It's interesting to note that Slide Rule s are called Logarithmic Rules in some countries.

We were the last class to use slide rules at my electronics school. I still keep one around. My old bamboo Post disappeared so I've got a Pickett. Great for electronics.

Yea verily... sliderules do indeed still rock.

My uncle gave me a slide rule for a birthday present back in the 70’s. I think it was an eclipse. Sadly I didn’t treat it well as it was the beginning of the hand calculator era. Kids these days don’t know how to use slide rules or even log tables... I use to love using log tables.

My slide rule at college was a Casio FX82. That was back in 1982/3. I still have it and it still works. I've never used a slide rule but my dad was using them until his sight packed up. They will probably come to me one day, and I will have to learn how to use them just out of curiosity.

Yessss! Have my great-grandfather's slide rule.

Talking of verniers, they're often built into the ironsights of precision target rifles, measuring miniscule elevation and windage adjustments. This allows a shooter to be able to dial his/her rifle without having to take a lot of zeroing shots each time they shoot at a different distance. This reduces cost (of ammunition expended), time taken to shoot a particular detail, and wear on their barrels. Plus, with adequate testing and practice, allows the shooter to make educated adjustments for atmospheric changes.

We used cylindrical slide rules in my school in the UK - they have the scales wrapped around a sliding cylinder and effectively made for a 12 foot slide rule which increased accuracy ( also prevented the masters from whacking you over the head with it). Haven't seen one of those in years though.

I found a slide rule at a thrift store a couple of weeks ago. The moment I saw it my jaw dropped, eyes popped open, and inhaled audibly. I was looking for one since forever and now I have it and it only cost me $3.35 (Beaver bucks, as is the tradition here in Soviet Canuckistan).

I still have my Helix A103W slide rule I got in 1969, I have to admit I've become a little rusty in using it so thank you for the refresher.

Yes! This is great content! Been fascinated with these and their predecessor, the Sector, for years. Thanks.

I have my dad's slide rule and pull it out and use it occasionally. If one has to do repeat calculations or ratios, it's still much faster than a calculator. Pilots still learn to use a version of one for figuring out course vectors with wind taken into account. Yes, most use a computer or tablet, but those can fail and you'd still better be able to get where you're trying to go.

In the early ‘70s in secondary school I used logarithms to calculate things but I used slide rules to get an approximate value to see if my log calculations were in the ball park. I had to calculate chemical amounts to 4 decimal places which was a PITA and the simplest logs calculations would take up a whole page of working. Calculators were a boon in 1975 when the prices came down.

My dad showed me, how to use a slide rule in the 1970s before we had calculators. Ok, he also had an electronic calculator with nixie tubes, which was fascinating. I think, it could add, subtract, multiply, but it could not divide. In the 1980s, I have made myself a music slide rule for music theory. My teacher was completely fascinated about it, back then. When my son learned some music theory, I have built him a music slide rule, too. His teacher was fascinated, too :-) A year ago, I have made a circular music slide rule, which is even more handy :-) Oh... before the end of your video, I have bought a slide rule from ebay. I am such a hoarder :-))))

Holy cow! Thanks Fran! This was the one thing I wanted to digest for my side project this week! :)

You've reminded me of "Slipstick" Libby in Heinlein's books! Thanks Fran, I've known of these devices but never seen one used close up. Facinating!

I have a book on how to use a slide rule by Isaac Asimov. In the introduction he says, "we have all heard these days of the invention of electronic computers, but to use an electronic computer to do simple arithmetic would be like shooting a fly with naval artillery."

I graduated highschool in 1973 and went on to attend engineering classes at university. We were told to buy the new Texas Instruments graphing calculator. I never figured out how to use either the slide rule(which we were also told to acquire) or the Calculator. They continue to be a mystery to me, as are logs and derivatives.. obviously I dropped out of classes.

Thanks Fran, never had a clue about slide rules at school...now I understand

I was taught how to use a slide rule in Secondary School in the early 1950's. We could use them in class and at home, but not during examinations! I still have both of mine, a Sun-Hemmi 149A (6") and a Sun-Hemmi 190 (12"). I used them for many years until electronic calculators came along. I went through several of those, ending up with an HP 42S. My grandchildren think that the slide rule is magic - they never learned about logarithms and trig functions.

I have two Pickett slide rules. They're re pretty amazing when you think about the fact that the Apollo astronauts took them to the moon. Slide rules are great at multiplication and division, addition and subtraction (which you "can" do if you jump through some hoops), and, of course, trig log functions. Most slide rules are accurate to the 2nd or "maybe" the 3rd decimal place which is perfect for most real-world applications.