# Why we need the metric system **URL:** \ **Category:** In My Humble Opinion\ **Created:** [September 17, 2010, 10:28pm UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140 "2010-09-17T22:28:19Z")\ **Posts on this page:** 20\ **Page:** 3
**Author:** ![CutterJohn](https://avatars.discourse-cdn.com/v4/letter/c/91b2a8/32.png) [@CutterJohn](https://boards.straightdope.com/u/CutterJohn)\ **Post date:** [September 19, 2010, 8:25am UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140/41 "2010-09-19T08:25:40Z")
I could care less which is used. I’m used to US standard, so its easy to figure things in my head with it, but I could get used to metric. I don’t care which one everyone uses though, just pick _one_. Metric, or standard, because I am sick and tired of having to buy two sets of all of my tools. ---
**Author:** ![Mogle](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mogle/32/12021_2.png) [@Mogle](https://boards.straightdope.com/u/Mogle)\ **Post date:** [September 19, 2010, 10:01am UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140/42 "2010-09-19T10:01:34Z")
> [@tracer](#): > > Personally, I think some of the metrification the world has undergone hasn’t gone far enough. The Metric System as used in most places isn’t the same thing as S.I. units. Most metric-speaking countries use liters (instead of cubic meters), kilograms of weight (instead of kilograms of mass), degrees Celsius (instead of Kelvins), speeds in kilometers per hour (instead of meters per second), et cetera. Lets see, the litre(which was a part of the original French system) and the hour are both on the [list](http://www.bipm.org/en/si/si_brochure/chapter4/table6.html) of non-SI units accepted for use with the SI, m[sup]3[/sup] is simply a very large unit and we do use it when dealing with large volumes. While the degrees Celsius may be a legacy unit it is still a [part of SI](http://www.bipm.org/en/si/si_brochure/chapter2/2-2/table3.html). The whole “kilograms of weight”(and “pounds of weight” too for that matter, the avoirdupois pound is a unit of mass, not force) is a matter of sloppy language, originating I suspect, from the fact that in a constant gravitational field(ie what people experience in everyday life) weight and mass are intrinsically tied. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [September 19, 2010, 10:41am UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140/43 "2010-09-19T10:41:25Z")
The key advantage with the metric system is that any quantity measurement is only ever expressed as a single unit, which makes calculations handling those quantities simple, usually single operations. Three times 140 centimetres is 420cm. One quarter of 140 cm is 35cm The same calculations on a measurement of 4 foot 7 will require an intermediate step of conversion into a single unit and perhaps another step converting the single-unit answer back into feet and inches. There’s no reason, of course, why non-metric measurements can’t also be handled in pure, single units, but that doesn’t seem to have happened for most of pre-metric history. ---
**Author:** ![tracer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tracer/32/20578_2.png) [@tracer](https://boards.straightdope.com/u/tracer)\ **Post date:** [September 19, 2010, 9:00pm UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140/44 "2010-09-19T21:00:05Z")
> [@Mogle](#): > > the avoirdupois pound is a unit of mass, not force Says who? Last I checked, pounds were units of force, and special “pound mass” units had to be derived from them to refer to mass. ---
**Author:** ![tracer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tracer/32/20578_2.png) [@tracer](https://boards.straightdope.com/u/tracer)\ **Post date:** [September 19, 2010, 9:01pm UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140/45 "2010-09-19T21:01:52Z")
> [@Mangetout](#): > > The same calculations on a measurement of 4 foot 7 will require an intermediate step of conversion into a single unit and perhaps another step converting the single-unit answer back into feet and inches. … which the British had to put up with with their currency system for a long time, too. (1000 pence was “4 pounds, 3 shillings, 4 pence” or “4 pounds 3 and 4” until the decimalification of British currency in, what was it, the 1970s?) ---
**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\ **Post date:** [September 19, 2010, 9:04pm UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140/46 "2010-09-19T21:04:26Z")
> [@Sage\_Rat](#): > > On the other hand, if I’m traveling in meters per second, I’ll have fuck-all idea how far I’ve gone in an hour. Humans walk at a meter per second. It’s about as natural a speed unit as you could dream up. ---
**Author:** ![Balthisar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/balthisar/32/2825_2.png) [@Balthisar](https://boards.straightdope.com/u/Balthisar)\ **Post date:** [September 19, 2010, 9:23pm UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140/47 "2010-09-19T21:23:38Z")
The US is already metric. All of these metric proposals are aimed at getting everyday folk to use the metric system, for which there \*are[i/] advantages, but not any advantages to people that cause them to switch of their own free will. As in economics, it’s all about incentives, and there just no incentive for normal, everyday people to switch. Business is obviously influenced by incentives, and everywhere that it matters (i.e., economically), we’re already metric. ---
**Author:** ![Mogle](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mogle/32/12021_2.png) [@Mogle](https://boards.straightdope.com/u/Mogle)\ **Post date:** [September 19, 2010, 9:34pm UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140/48 "2010-09-19T21:34:55Z")
> [@tracer](#): > > > [@Mogle](#): > > > > the avoirdupois pound is a unit of mass, not force > > Says who? Last I checked, pounds were units of force, and special “pound mass” units had to be derived from them to refer to mass. Says the definition, the avoirdupois pound is [defined](http://en.wikipedia.org/wiki/Pound_(mass)#International_pound) as 0.45359237 kg, I don’t know how they came up with it to begin with but that is the current definition. ---
**Author:** ![Raguleader](https://avatars.discourse-cdn.com/v4/letter/r/258eb7/32.png) [@Raguleader](https://boards.straightdope.com/u/Raguleader)\ **Post date:** [September 19, 2010, 9:50pm UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140/49 "2010-09-19T21:50:48Z")
> [@Balthisar](#): > > The US is already metric. All of these metric proposals are aimed at getting everyday folk to use the metric system, for which there \*are[i/] advantages, but not any advantages to people that cause them to switch of their own free will. As in economics, it’s all about incentives, and there just no incentive for normal, everyday people to switch. > > Business is obviously influenced by incentives, and everywhere that it matters (i.e., economically), we’re already metric. Yeah, as has been pointed out before, we’ve been using Metric since at least the 80’s. I’ve almost always seen rulers with centimeters marked on the opposite edge, which actually makes the ruler pretty handy for making at least one set of conversions. ---
**Author:** ![Tangent](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tangent/32/3098_2.png) [@Tangent](https://boards.straightdope.com/u/Tangent)\ **Post date:** [September 19, 2010, 9:52pm UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140/50 "2010-09-19T21:52:04Z")
Who needs pounds-mass when we’ve got [slugs](http://en.wikipedia.org/wiki/Slug_(mass))? ---
**Author:** ![tracer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tracer/32/20578_2.png) [@tracer](https://boards.straightdope.com/u/tracer)\ **Post date:** [September 19, 2010, 10:38pm UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140/51 "2010-09-19T22:38:00Z")
> [@Mogle](#): > > Says the definition, the avoirdupois pound is [defined](http://en.wikipedia.org/wiki/Pound_(mass)#International_pound) as 0.45359237 kg, I don’t know how they came up with it to begin with but that is the current definition. Huh. I’ll be darned. The pound-force article on Wikipedia confirms it: The pound of force is defined as the weight of one pound of mass at the surface of the Earth, and not the other way around. ---
**Author:** ![Apollyon](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/apollyon/32/4238_2.png) [@Apollyon](https://boards.straightdope.com/u/Apollyon)\ **Post date:** [September 20, 2010, 1:48am UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140/52 "2010-09-20T01:48:19Z")
> [@tracer](#): > > Most metric-speaking countries use liters (instead of cubic meters)… Well, I don’t _mind_ the idea of buying my fruit juice in cubic meters.. but the supermarket is going to have to provide much more sturdy trolleys, 'cos that’s going to weigh like 158 stone or something… 🙂 ---
**Author:** ![gonzomax](https://avatars.discourse-cdn.com/v4/letter/g/e8c25b/32.png) [@gonzomax](https://boards.straightdope.com/u/gonzomax)\ **Post date:** [September 20, 2010, 1:57am UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140/53 "2010-09-20T01:57:54Z")
The reason is interchangeability throughout the world. If you sell a replacement product to an European company, it has to fit into their system. You can’t remove something with MMs and plug in something built in inches. Our corps are international and have to sell things in all countries. Since almost all are in MMs, we have to accommodate them. ---
**Author:** ![sisu](https://avatars.discourse-cdn.com/v4/letter/s/df705f/32.png) [@sisu](https://boards.straightdope.com/u/sisu)\ **Post date:** [September 20, 2010, 2:14am UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140/54 "2010-09-20T02:14:42Z")
In Australia metric came in the year I was born. I am one of those people who love metric for calculations, I can do it in my head but still use it say someone is 6’2" etc. Funny but I know how tall a 6’ person is in my head but struggle with 180cms. ---
**Author:** ![tracer](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tracer/32/20578_2.png) [@tracer](https://boards.straightdope.com/u/tracer)\ **Post date:** [September 20, 2010, 2:17am UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140/55 "2010-09-20T02:17:31Z")
> [@Apollyon](#): > > Well, I don’t _mind_ the idea of buying my fruit juice in cubic meters.. but the supermarket is going to have to provide much more sturdy trolleys, 'cos that’s going to weigh like 158 stone or something… 🙂 Or 643,015 pennyweights. 😛 ---
**Author:** ![Sunspace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/sunspace/32/1250_2.png) [@Sunspace](https://boards.straightdope.com/u/Sunspace)\ **Post date:** [September 20, 2010, 2:36am UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140/56 "2010-09-20T02:36:27Z")
> [@Apollyon](#): > > > [@tracer](#): > > > > Most metric-speaking countries use liters (instead of cubic meters)… > > Well, I don’t _mind_ the idea of buying my fruit juice in cubic meters.. but the supermarket is going to have to provide much more sturdy trolleys, 'cos that’s going to weigh like 158 stone or something… 🙂 1 cubic metre of water (or fruit juice, which is mostly water) = 1000 kg (1 tonne)! Easy-peasy! Thanks to the OP for pointing out the origin of the cooling “ton” (the rate of heat removal of one US short ton (2000 pounds) of ice melting in one day). That one had confused me for meny years. And the ship’s “ton” can be a unit of _volume_. [Gah](http://en.wikipedia.org/wiki/Ton). ---
**Author:** ![jasonh300](https://avatars.discourse-cdn.com/v4/letter/j/46a35a/32.png) [@jasonh300](https://boards.straightdope.com/u/jasonh300)\ **Post date:** [September 20, 2010, 3:04am UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140/57 "2010-09-20T03:04:40Z")
> [@Sunspace](#): > > There is a way things could be worse though: you could be living in a country that stopped metric conversion halfway through, and as a result live your life in a half-assed stew of three different systems of measurement: the US, the Imperial, and the metric. We did a design recently that had three different values for the volume of a cistern: US (liquid) gallons, Imperial (liquid) gallons, and litres. > > Yeah, building in Canada is such a pain. I didn’t see a whole lot of anything that wasn’t metric in Canada, but did you begin your education before the mid 1970s? I have a friend in Canada who’s kids were educated well after the conversion, but they measure weight in pounds and if you ask them for directions–how far is it to whatever–they give you a dumb look and tell you it’s about 20 minutes away. They have absolutely no concept of distance other than a person’s height which they express in feet and inches. They understand speed in km/h and I think they understand the Celcius scale. These are bright kids, honors students and 2 of the 4 are in college now. ---
**Author:** ![Martini\_Enfield](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/martini_enfield/32/11123_2.png) [@Martini\_Enfield](https://boards.straightdope.com/u/Martini_Enfield)\ **Post date:** [September 20, 2010, 3:13am UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140/58 "2010-09-20T03:13:47Z")
> [@sisu](#): > > In Australia metric came in the year I was born. I am one of those people who love metric for calculations, I can do it in my head but still use it say someone is 6’2" etc. > > Funny but I know how tall a 6’ person is in my head but struggle with 180cms. Also interestingly, despite the fact distances (and speeds thereof) are done in metric (MM, C, Km, Km/h etc) TV screens and computers are still sold with inches and most people I know- even younger people- still use feet and inches for a person’s height. ---
**Author:** ![Spoons](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/spoons/32/3141_2.png) [@Spoons](https://boards.straightdope.com/u/Spoons)\ **Post date:** [September 20, 2010, 4:41am UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140/59 "2010-09-20T04:41:40Z")
Wrong thread, sorry. ---
**Author:** ![Jragon](https://avatars.discourse-cdn.com/v4/letter/j/e19b73/32.png) [@Jragon](https://boards.straightdope.com/u/Jragon)\ **Post date:** [September 20, 2010, 5:40am UTC](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140/60 "2010-09-20T05:40:59Z")
But guys, what number of horns on a unicorn acre are in US teaspoons per lightyear? [Previous page](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140.md?page=2) [Next page](https://boards.straightdope.com/t/why-we-need-the-metric-system/554140.md?page=4)