Slide Rules Part 1: Multiplication.

Today I show you an outdated piece of technology! It's still pretty cool though. So let's take a leap back in time and learn about: The Slide Rule! Enjoy!

[Inaflap]

The A and B scales can be used like this, but the C and D scales allow for greater precision in multiplication and division. As you pointed out, the 1 on the A (and B) scale marked just half-way along the rule is 10x the value of the 1 at the leftmost edge. On the C and D scales, 1 to 10 is spread across the full length of the rule. Also the subdivisions on C between 1 and 2 are usually numbered. The A and B scales are intended for solving squares (and roots) of the C and D values. The K scale will show the cube (and cube root on D).

[realtoast]

As a kid in the '70s, every smart kid had one of these. I could only look on in wonder.

[jadenephrite]

Although the A and B scales can be used for multiplication and division, as a better alternative, the C and the D scales are usually used for multiplication and division, because they have twice the precision as compared to using the A and B scales. On the other hand, the A and B scales are usually used for finding square roots or squares, because the A and B scales each contain double the decade of the C and D scales. The K scale is used for finding cube roots or cubes, because the K scale contains triple the decade of the C and D scales. The CI scale is the Inverse of the C scale and is used for finding the reciprocals of numbers.

[balluumm]

Great work Max, I still have my slide rule from fifty years ago. My daughter took it to school to show her maths teacher and she had never seen one before.

[Boltkiller]

i am from the past, i came here for the tutorial

[greatwallofcrew]

Thanks so much for the tutorial! We recently saw a slide rule for the first time and had no idea what to do with it. But after watching your tutorial, my son was able show his Nana how to use it, and she gave it to him! Thanks for teaching it so clearly. You may enjoy the book "Number Stories from Long Ago" by Smith

[mnpd]

I'm in my 70's and almost all I have to say is...thank God for calculators. Even though the first pocket calculator hit the shelves in 72-73 (My memory is that it was 73 and the HP 36) the items were unavailable to the average person due to their costs. Even in 74 I remember a calculator that could perform only MDAS functions was $800.... that is thousands in today's currency. Schools and universities did not allow calculators until c. 1980 because the things gave a terrific advantage to rich students on timed examinations. I took my Frederick Post slide ruler out a couple years back and realized that I had no idea how to use it.

[michaelryan-oejq]

Interesting. But please try and keep the camera steadier otherwise difficult to follow.

[earthgirl]

Watching Apollo 13 brought me to this video. Thank you. 🙌

[PatMarron]

Hi Max- Just heard about your post today from Uncle Mike. I'm his dad. Yesterday I was unpacking some boxes i had packed in 1993. Inside was my slide rule. I decided to pack it in my luggage for a visit to Uncle Mike next week-end. It's a weird coincidence! I graduated in 1969 with EE degree pre- calculator days.

[MarvinClarence]

Using the C and D scales are more effective and accurate

[douglasstrother]

My Dad showed me how to use his Keuffel & Esser slide rule when I was a kid.
After he passed, I found the manual.
Still have both, so I can still Engineer when California shuts-off the electricity.

[briandenley]

Once I bought a calculator, I never wanted to see my slide-rule again!

[stephenlief]

Thank you Max! I just got my first slide rule from eBay, and this was very helpful. Will this do trig functions also?

[pskrtv]

is this obi wan kenobi? "hello there"

[prof.dr.abronsius]

I have a 'pi' on the logscale itself, and an 'e'; but what does 'c' mean??

[riadriddick]

AVENDRE: J'ai 140 règles de calcul tout neuf N°57/88-Reitz-N-Etudiant & N°57/89-ETUDIANT LOG LOG.Fabrication allemagne en 1965.

[robinj.]

Strange.
Was there something wrong with your C and D

[TnseWlms]

Who are the kids that will make me smarter?

[nativetexan]

You lost me after the first sentence. I never have, nor will I ever, be able to comprehend one of these. All I see when I look at one of these is a bunch of numbers on a sliding ruler.