A Millibar

[Khandro]

Just looking up what a millibar was on my barometer and found;

'A millibar is 1/1000th of a bar and is approximately equal to 1000 dynes (one dyne is the amount of force it takes to accelerate an object with a mass of one gram at the rate of one centimeter per second squared). Millibar values used in meteorology range from about 100 to 1050.'

Not alot of people know that! Did you? 🙄

[Old_Geezer]

I knew the first bit. Never bothered to look up the rest though.

[Peter Pedant]

well if the deleters didnt know...it will be deleted !

I thought it was one atmosphere ( it almost is) - well OK for pedants a thouthandth of an atmosphere.

CGS has gone thank god  - ya know that there is a word in Thpanith for - pertaining to the CGS metric system

cegesimal.....not much used now

The real prob with CGS is that electromagnetism was chaotic - the equations had correctors of 10, 10^7 and ten to eighth

SI uses - one (1).

oh and the arabic for cm is - -  "sum"

[Old_Geezer]

Always seemed strange that milli represented 1/1000

After all a milli-on ain't 1×1000, it's 1×1000000.

[sandyRoe]

No.  I didn't know that.

[Peter Pedant]

Oh, incomporated in the orignal metric system

mm -  a thousand make up a metre

cm - 100 to a metric

When the uni library had books, Manch had a Phil Society. Fits and starts. Three foundations and so there are three Vol 1 's of he Manch. Philosophical Society. And there was actually a paper explaining the new parisian metric system ( 1796) I think.

I was looking to see if John Dalton had presented any paper provincially on his atomic theory. ( he hadnt) - or as others say, "he googles very quickly". So theonly thing is to sit down at 1795 and go thro until 1805

[Etch]

You don't give the source of your quote Khandro, but the dyne is a unit of force whereas millibars/bars are units of pressure (force per unit area). So a millibar is approximately 1000 dynes per square centimeter. The International Standard Atmosphere ISA) uses a value of 1013.25 millibars for atmospheric pressure at sea level.

https://en.wikipedia.org/wiki/International_Standard_Atmosphere

 

[Khandro]

I'm afraid I can't get my brain around it, I'm more into visuals such as ref. PP,s: //the new parisian metric system ( 1796) I think.//

I know the world's standard metre, from which all things are measured, is a gold rod in the Paris Science Museum. That I can relate to.

But I read recently it has been pointed out that it looses atoms somehow, so it will eventually be no longer a metre in length.

panta rhei  (all things are in flux) Heraclitus. 🙂

[Old_Geezer]

Since 1983, the metre has been internationally defined as the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second.

 

Take that Paris bar ;-)

[ToraToraTora]

a milli bar is 1000th of a bar! well who'd have thunk it? Next you'll be telling me a millimetre is 1000th of a metre!

[Khandro]

^^ Yes, but that calculation was done with reference to the Paris bar. 

Another different Paris bar, one I used to frequent in my days there, was called Le Cinq Billiards in Place de la Contrescarpe.

[Khandro]

Barometer readings are given in an array of formats, if you want to know the difference between, HG, PSI, ATM, mbar, mmHg and kPa, this is a good site. Just click on the format you want under the dial;

https://barometricpressure.app/content/understanding-high-low-pressure-readings