# Metric vs \_\_\_\_\_\_\_\_ ? **URL:** \ **Category:** Factual Questions\ **Created:** [July 18, 2001, 6:06pm UTC](https://boards.straightdope.com/t/metric-vs-________/72954 "2001-07-18T18:06:08Z")\ **Posts on this page:** 4\ **Page:** 2
**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:** [July 19, 2001, 6:38pm UTC](https://boards.straightdope.com/t/metric-vs-________/72954/21 "2001-07-19T18:38:59Z")
> [@](#): > > the mole for amount of substance, and > the candela for intensity of light. You can scratch these two off the list, if you’d like. Moles aren’t really a unit of anything; you can eliminate them entirely if you’re not afraid of scientific notation. Don’t say that you have 3.2 moles of hydrogen molecules; say instead that you have 1.972\*10[sup]24[/sup] hydrogen molecules. For intensity of light, watts (defined in terms of meters, kilograms, and seconds) work just fine. Of course, _real_ physicists don’t bother with any units at all, and measure everything in Plancks. CGS and MKS (SI) are both metric systems, but there’s still other metric units which don’t belong to either system. The parsec and the calorie, for instance, are both commonly used with the metric prefixes, and the calorie is based (originally) on metric units, albeit in a different manner than the Joule. ---
**Author:** ![Rayne\_Man](https://avatars.discourse-cdn.com/v4/letter/r/df705f/32.png) [@Rayne\_Man](https://boards.straightdope.com/u/Rayne_Man)\ **Post date:** [July 19, 2001, 6:40pm UTC](https://boards.straightdope.com/t/metric-vs-________/72954/22 "2001-07-19T18:40:31Z")
I work in the natural gas industry and here in the UK the standard measure of pressure is the BAR ( 1 BAR= 1 Atmosphere = approx 15psi . Another pressure unit in use in Europe is the Pascal . So even here there are two rival metric pressure unit in use. ---
**Author:** ![Bartman](https://avatars.discourse-cdn.com/v4/letter/b/779978/32.png) [@Bartman](https://boards.straightdope.com/u/Bartman)\ **Post date:** [July 19, 2001, 7:19pm UTC](https://boards.straightdope.com/t/metric-vs-________/72954/23 "2001-07-19T19:19:08Z")
Of course I would be remiss not to link to [http://www.unc.edu/~rowlett/units/index.html](http://www.unc.edu/~rowlett/units/index.html). It demonstrates the mind boggling number of units available. Any thing that has references like the following can’t be all bad. > [@](#): > > langdo > a traditional unit of land area in Bhutan. Like many European land units, the langdo is the area that a team of oxen can plow in a day. If the land is dry, a langdo is about 1/7 hectare or 1/3 acre; for a wet paddy field the langdo is about 1/10 hectare or 1/4 acre. or how about > [@](#): > > degree Twaddle (°Tw) > a unit measuring the specific gravity of liquids denser than water. 1 °Twaddle represents a difference in specific gravity of 0.005 or 1/200, so a liquid of specific gravity S is measured at 200(S - 1) °Tw. or even the > [@](#): > > olf > an empirical unit of indoor odor intensity introduced by the Danish environmental scientist P.O. Fanger in 1988. One olf is defined as the air pollution produced by one ‘standard’ person (a standard person is also defined). Ventilation reduces pollution, and the resulting pollution in ventilated, enclosed spaces is measured in decipols. ---
**Author:** ![sailor](https://avatars.discourse-cdn.com/v4/letter/s/a587f6/32.png) [@sailor](https://boards.straightdope.com/u/sailor)\ **Post date:** [July 19, 2001, 8:16pm UTC](https://boards.straightdope.com/t/metric-vs-________/72954/24 "2001-07-19T20:16:18Z")
When it comes to pressure, while the scientific community uses “correct” units, engineers and plnbers tend to use practical units like Kg/cm2 and meters of water column. A bar and an atmosphere are [not equivalent](http://www.unc.edu/~rowlett/units/dictB.html) > [@](#): > > bar: a metric unit of atmospheric pressure, equal to one million dynes per square centimeter, 100 kilopascals, 750.062 torr, 1.019 72 kilograms of force per square centimeter (kgf/cm2), or about 14.503 78 pounds per square inch (lbf/in2). The word comes from the Greek baros, “weighty.” We see the same root in our word, barometer, for an instrument measuring atmospheric pressure. One bar is just a bit less than the average pressure of the Earth’s atmosphere, which is 1.013 25 bar. China has retained the old names for the new metric units. They had a unit of weight which was about a pound so they made it 1/2 kilo. It is a bit strange to go about China and buy stuff by the half kilo. (of course, just when I need it the name escapes me… I was not even 20 when my girlfriend told me I was a forgetful dirty old man… and since then I’ve gotten worse on both counts) [Previous page](https://boards.straightdope.com/t/metric-vs-________/72954.md?page=1)