# Standard Units: why 'cgs' and 'mks' not 'mgs'? **URL:** \ **Category:** Factual Questions\ **Created:** [November 23, 2009, 3:43pm UTC](https://boards.straightdope.com/t/standard-units-why-cgs-and-mks-not-mgs/518646 "2009-11-23T15:43:56Z")\ **Posts on this page:** 8\ **Page:** 2
**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\ **Post date:** [November 24, 2009, 5:37pm UTC](https://boards.straightdope.com/t/standard-units-why-cgs-and-mks-not-mgs/518646/21 "2009-11-24T17:37:15Z")
I agree with all who think tangling a prefix into the foundation of the system is needlessly irritating and amounts to a defeat snatched from the jaws of victory. My vote is to replace the “kilogram” with the “Einstein”, a mass unit of equal size. I don’t especially like calling it the “grave” even if that’s where Einstein is now, but it would still be better than the present situation. Also, let’s let the kilo- prefix be abbreviated with “K” rather than “k” so that all larger multipliers are uppercase and all smaller ones lowercase. Also, let’s replace the Greek lowercase Mu with the similar looking lowercase “u” so that all English computer character sets include a prefix for one millionth. Finally, I propose that when talking about luminosity and lumens, the K and M and G multipliers suddenly become 1002, and 1,000,002, and 1,000,000,002, and so forth. This takes care of the issue that all unit systems apparently need some blindingly stupid nonsensical feature that threatens to mess up all hope of neat, tidy, predictable usage. However, it does so by spoiling an entire category of units that nobody cares about, which is actually sort of cheating. ---
**Author:** ![coffeecat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/coffeecat/32/3405_2.png) [@coffeecat](https://boards.straightdope.com/u/coffeecat)\ **Post date:** [November 24, 2009, 10:09pm UTC](https://boards.straightdope.com/t/standard-units-why-cgs-and-mks-not-mgs/518646/22 "2009-11-24T22:09:44Z")
> [@qazwart](#): > > The problem with the SI system is that you end up with some really screwy measurements. Take the unit of pressure, pascals, which are measured as newtons per square meter. A newton is the unit of weight which is mass times acceleration, so a 1 kilogram mass at sea level _weighs_ about 9.8 newtons. Spread a single newton (about 1/10 of a kilogram at sea level) over a square meter, and you have a single pascal. > > So, regular atmospheric pressure is about 100,000 pascals. Fill up a bike tire, and you’re talking about putting in 200 to 600 kilopascals. So, the Pascal is impractically small. On the scale of impartially big is the Farad which is the unit of capacitance. I don’t think power plants have capacitors as big as a single farad. Abfarads, statfarads, and dynes/cm[sup]2[/sup] aren’t any better. No matter what units you start with, something will be way too big or way too small. I say give up. > [@](#): > > I say to hell with it, and let’s go with the [Portzebie System of Weights and Measures](http://en.wikipedia.org/wiki/Potrzebie). It makes about as much sense. Ok, or go Mad™ :). ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [November 24, 2009, 10:19pm UTC](https://boards.straightdope.com/t/standard-units-why-cgs-and-mks-not-mgs/518646/23 "2009-11-24T22:19:17Z")
> [@](#): > > On the scale of impartially big is the Farad which is the unit of capacitance. I don’t think power plants have capacitors as big as a single farad. Any sane system of electrical units is inevitably going to have most of them be a really awkward size. We have a system where the volt is a practical size, and to a lesser extent the amp and the ohm, but the price we pay for that is that the coulomb, Tesla, and Farad are all too big for most purposes. We could instead have constructed a system where the coulomb is a practical size, but then all the rest would be inconvenient, and so on. > [@](#): > > My vote is to replace the “kilogram” with the “Einstein”, a mass unit of equal size. I don’t especially like calling it the “grave” even if that’s where Einstein is now, but it would still be better than the present situation. Can’t do that; there’s already a unit called an “Einstein”. It’s a really obscure temperature unit that hardly anyone ever uses, but you can’t (or rather, shouldn’t) use the same name for two different units. > [@](#): > > Finally, I propose that when talking about luminosity and lumens, the K and M and G multipliers suddenly become 1002, and 1,000,002, and 1,000,000,002, and so forth. This takes care of the issue that all unit systems apparently need some blindingly stupid nonsensical feature that threatens to mess up all hope of neat, tidy, predictable usage. However, it does so by spoiling an entire category of units that nobody cares about, which is actually sort of cheating. Eh, lumens are already silly. SI already has a perfectly good unit for luminosity: The watt. The only thing that makes lumens not really power units is that you’re passing the light through a frequency filter that roughly corresponds to the response of the human eye, but that’s way too arbitrary to consider it a fundamental unit. Likewise, we could scratch the mole off the list, too, and just give numbers (what’s the matter, chemists, afraid of scientific notation?). ---
**Author:** ![Fridgemagnet](https://avatars.discourse-cdn.com/v4/letter/f/22d042/32.png) [@Fridgemagnet](https://boards.straightdope.com/u/Fridgemagnet)\ **Post date:** [November 24, 2009, 10:21pm UTC](https://boards.straightdope.com/t/standard-units-why-cgs-and-mks-not-mgs/518646/24 "2009-11-24T22:21:45Z")
> [@Svejk](#): > > You can’t have two prefixes. A CAD simulation I ran last week returned an answer in mdB (millidecibels). But what else could it do when the base unit is dB? Personally I’d have made the Bel 10X smaller, and I never have been happy with the kg as a base unit, it just doesn’t sit right. Mind, no-one calls a ton a Mg… > [@Napier](#): > > Also, let’s let the kilo- prefix be abbreviated with “K” rather than “k” so that all larger multipliers are uppercase and all smaller ones lowercase. You’ll have the [Kibi-kilo](http://en.wikipedia.org/wiki/Binary_prefix#IEC_standard_prefixes) police down on you! ---
**Author:** ![The\_Hamster\_King](https://avatars.discourse-cdn.com/v4/letter/t/8edcca/32.png) [@The\_Hamster\_King](https://boards.straightdope.com/u/The_Hamster_King)\ **Post date:** [November 24, 2009, 10:27pm UTC](https://boards.straightdope.com/t/standard-units-why-cgs-and-mks-not-mgs/518646/25 "2009-11-24T22:27:02Z")
Now … how many bytes are there in a terabyte? 😃 ---
**Author:** ![Cazzle](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cazzle/32/75_2.png) [@Cazzle](https://boards.straightdope.com/u/Cazzle)\ **Post date:** [November 24, 2009, 10:37pm UTC](https://boards.straightdope.com/t/standard-units-why-cgs-and-mks-not-mgs/518646/26 "2009-11-24T22:37:30Z")
> [@DrFidelius](#): > > I’l go out on a limb here and point out that the system was invented by the French, therefore neither efficiency nor internal logic was ever a consideration. > > (If I ever used smilies, one would appear here.) Unlike those ever-so logical Americans who write their date in the order ‘MM-DD-YYYY’ 😛 ---
**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\ **Post date:** [November 25, 2009, 1:50pm UTC](https://boards.straightdope.com/t/standard-units-why-cgs-and-mks-not-mgs/518646/27 "2009-11-25T13:50:36Z")
> [@Fridgemagnet](#): > > A CAD simulation I ran last week returned an answer in mdB (millidecibels). But what else could it do when the base unit is dB? Personally I’d have made the Bel 10X smaller, and I never have been happy with the kg as a base unit, it just doesn’t sit right. Mind, no-one calls a ton a Mg… You should be using Nepers in the first place - a truly splendid idea, Nepers - unmatched, really - origin of the name is obscure, though. ---
**Author:** ![mbh](https://avatars.discourse-cdn.com/v4/letter/m/a6a055/32.png) [@mbh](https://boards.straightdope.com/u/mbh)\ **Post date:** [November 25, 2009, 5:03pm UTC](https://boards.straightdope.com/t/standard-units-why-cgs-and-mks-not-mgs/518646/28 "2009-11-25T17:03:00Z")
> [@qazwart](#): > > On the scale of impartially big is the Farad which is the unit of capacitance. I don’t think power plants have capacitors as big as a single farad. When I was a sophomore E.E. student, our lab equipment was all geared to five volts. The capacitors were mostly in the microfarad and millifarad range. They looked like coin-sized discs with two wires coming out of one edge. One day, we came into the lab and found a cylindrical object, slightly smaller than a beer can. On one end, in fine print was a number. I don’t remember the exact number. It was either “900 mF”, or “1100 mF”. For the first time in our lives, we saw a capacitor that was on the order of one farad! So, naturally, we put five volts across it, and then used a piece of steel plate to short the terminals. The spark melted a notch into the steel. We went home very happy, that day. Never did find out where it came from, or what happened to it afterward. [Previous page](https://boards.straightdope.com/t/standard-units-why-cgs-and-mks-not-mgs/518646.md?page=1)