metric usage

The meteorology used to use millibars, so the standard air pressure is 1013.25 mbar, but the current meteorological and aviation practice has converted over to hectopascals (hPa) which are numerically equal to millibars.

As a curiosity, Amercan aviation measures air pressure in inches of mercury (inHg), so the stnadard pressure is 29.92 inHg.

--
Here, in the German-influenced back corner of Europe, the car
thirst is usually measured as litres per 100 km.

Thanks! Rich

Part of it is because "standard" atmospheric pressure (101325 N/m^2) is: a) close to a power of 10 in SI units, and b) that power of 10 /isn't/ a power of 1000, and c) the value in SI units is numerically large.

So you have the SI unit of Newtons per square metre, which is useful enough to be given a name (Pascal).

But one atmosphere is roughly 10^5 Pa, or 100 kPa or 0.1 MPa, so one kPa is 100 times too small while one MPa is 10 times too large, hence the "bar" (100 kPa).

None of those are exactly standard atmospheric pressure, so you still have "atmospheres".

Then you have the historical legacy of measuring pressure using a mercury column, leading to Torr (millimetres of mercury).

Add in the confusion between weight (force) and mass and you get kilograms per square metre, analogous to the imperial PSI.

And all of that is before you consider any imperial measurements.

US pint beers aren't at all unusual in bars. I don't consider a pint a large beer at all. Some have 23oz. glasses, or even larger. Pizzeria Uno even had (haven't been to one in a couple of years) 23oz. glasses.

I prefer working in inches for PCB, we tend to be dual units over here.

I've met an OT (Occupational Therapist) who thinks mmol is same as mmHg, very sad, confusing blood glucose levels with blood pressure levels.

Thanks a freakin' lot ;) Where I fill up and check tyres the dual mode pressure gauge is usually sitting on 32psi. All tyre pressure gauges I've seen in .au are dual calibrated psi + kPa (I think?) about 200 of them match 32psi.

10oz 'pot' in Victoria, half a pint. Pint container was resized to 600ml for milk.

I'm happy with litres per 100km, which is upside down to miles per gallon but works okay in my head once I got used to it (20l jerry can adds X km range, back when I drove 4WD, and cared).

My car computer does the l/100km, so that must be the standard for .au, as l/100km used everywhere here.

Grant.

Or weight, mass and force?

Or linear dimension units? Metric, feet, inches, thous? Who here knows what a "thou" is? What a "tenth" is, among those dealing with "thou"?

Fraction -vs.- decimal?

Meanwhile, there are multiple measures of how many pints or quarts of BEvERages that I questionably drank, as well as 2 different gallons. I gas-up my car by the US gallon, while I hear that "US Gallon" is not the only gallon that I have to deal with.

However, there are "SI" (metric) units of mass, volume and force, also of weight and density.

At this rate, it strongly appears to me that there is only one liter/litre of volume measure that this world needs to deal with, especially for liquid fuel purchases at $ per unit-volume rates.

--
 - Don Klipstein (don@misty.com)

In meteorology, the millibar is a common pressure unit.

For that matter, pressure patterns aloft are normally shown as heights of achieving some specific pressure, such as 850, 700, 500, 300 or 200 millibars.

An "850 millibar" item usually has its pressure pattern having fair resemblance to surface pressure levels, with minor influence by temperature between surface and wherever aloft the "850 pressure level" is, along with correction for difference between land and sea level.

A "500 millibar analysis" map is fairly good at showing jet-stream winds and similar ones that result aloft from temperature gradient horizontally "existing" from surface to the 500-millibar height.

--
 - Don Kliopstein (don@misty.com)

Historical, application, locale? In my experience the US uses Torr, the Japanese Pascal and Euro mBar. But then I deal with low pressures for ion pumps and the like.

And really weird $hit like kilopond/sq. cm., wtf?

e knows

So don't get me going on this, can't we just have one friggin' standard? On a positive note, it does keep me up on doing math in my head ;-}. Case in point; traveling in Kiwi Land and I see the price of X in $NZ/kg and want to know $US/lb. Turns out chicken was more spendy than lamb. (And the green lip mussels were freakin' awesome @ $US 0.52/ lb.!)

Lee

...Who thinks the appropriate unit of measure for beer is a 'keg'! ;-}

[snip remaining bit of Don's diatribe]

If only it made sense to sell vehicle fuel by volume rather than mass ...

As fuel gets warmer, the volume (and thus cost) increases for a given amount of energy.

I don't like you.

The volumetric increase for liquid petrol is very little. It has a pretty good Reid vapor pressure in a sealed vessel (with head space, of course). The liquid itself doesn't vary a lot though, until actual media evaporates and gets carried away. In the vessel, it would just 'hang around', once the head space came up to the RVP number. The pressure in a can that got hotter is not because the liquid expanded, it is because the head space got charged to a higher RVP from the elevated temperature.

As far as the volumetric numbers go, it is like 6 cubic inches per gallon over a 50 degree F span.

Buy your gas cold.

Howard Hughes proved that liquids are compressible. He made jaws drop, that guy.

Not mine.

He designed a bra, too. That's why dimboob knows who he was.

--
You can't fix stupid. You can't even put a Band-Aid? on it, because it's
Teflon coated.

I'm sure he made yours drop... at least enough to fit the incoming.

1Cm is about the width of an adult thumbnail

--
Dirk

http://www.neopax.com/technomage/ - My new book - Magick and Technology

Projection noted.

Immature fantasy projection noted.

Which refers to your inability to keep sewage out of your mouth.

That's exactly what bras are designed to support.

Best regards, Spehro Pefhany

--
"it's the network..."                          "The Journey is the reward"
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