# The Naked Scientists Forum

### Author Topic: Bars and Atmospheres  (Read 2647 times)

#### Les the Scientist

• Jr. Member
• Posts: 39
##### Bars and Atmospheres
« on: 07/08/2005 03:54:45 »
How does the very slight difference in numerical value come about ?

#### David Sparkman

• Sr. Member
• Posts: 234
##### Re: Bars and Atmospheres
« Reply #1 on: 07/08/2005 04:07:24 »
I suppose you are refering to a measure of Barometric pressure called millibars or bars for short. The atmosphere is one big heat exchanger moving hot air to cooler locations and cool are to warmer locations. The mechinism is the fact that cooler air is more condensed then warmer air, and thus weights more. (hot air rises concept)

The barometric pressure falls when the air above us gets lighter (warmer), and rises when it gets colder. Warm air generally has more water in it, and cold air has less. When the bars rise or fall rapidly, you are on a battlefield of two air masses and may get wet.

David

#### Les the Scientist

• Jr. Member
• Posts: 39
##### Re: Bars and Atmospheres
« Reply #2 on: 07/08/2005 16:21:22 »
Well I kinda meant why is there 14.5 psi in 1 bar and 14.7 psi in 1 atmosphere ?  I didn't really mean 'atmosphere' as in wind and air :o/

#### Tronix

• Full Member
• Posts: 59
##### Re: Bars and Atmospheres
« Reply #3 on: 08/08/2005 15:09:54 »
but hey, that answered my question on how a barometer works (or at least what it measures). thanks Dave

--------------------------------------------
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The BPRD rejected my application becuase their brain-controled by Cthulhu Rip-offs. And im sure "Sparky" is sleeping with them too, kinky little firecracker she is...

#### Simmer

• Sr. Member
• Posts: 229
##### Re: Bars and Atmospheres
« Reply #4 on: 08/08/2005 22:40:40 »
A bar is 100,000 Pascals (Newtons per square meter).  Chosen as a nice round number which is conveniently close to average air pressure at sea level, I should think :-)

#### The Naked Scientists Forum

##### Re: Bars and Atmospheres
« Reply #4 on: 08/08/2005 22:40:40 »