----- Original Message -----
From: "Carter, Baron" <[EMAIL PROTECTED]>
To: "U.S. Metric Association" <[EMAIL PROTECTED]>
Sent: Wednesday, 2004-04-21 18:37
Subject: [USMA:29605] Re: Air pressure
history
Do these help?
No, half of what you printed below is
gibberish. Only the temperatures are understandable.
Euric
http://nssdc.gsfc.nasa.gov/space/model/atmos/us_standard.html
The ICAO standard atmosphere for the continent of North America, based on
summer and winter averages at latitude 40� assumes the following conditions:
1. The air is a perfectly dry gas.
2. A mean sea level pressure of 29.92 inches of mercury.
3. A mean sea level temperature of 15�C.
4. The rate of decrease of temperature with height is 1.98�C per 1000 feet.
http://history.nasa.gov/SP-367/chapt2.htm
-----Original Message-----
From: Pat Naughtin [mailto:[EMAIL PROTECTED]
Sent: Wednesday, April 21, 2004 15:45
To: U.S. Metric Association
Subject: [USMA:29598] Re: Air pressure history
Dear Mike,
No, I had no response.
As you can see, I have reposted this to the USMA list. Maybe someone there
can help this time.
Cheers,
Pat Naughtin LCAMS
Geelong, Australia
--
on 2004-04-21 23.11, Michael Payne wrote:
> Did you ever get an answer to this Pat?
>
> Mike Payne
>
>
>> [Original Message]
>> From: Pat Naughtin <[EMAIL PROTECTED]>
>> To: U.S. Metric Association <[EMAIL PROTECTED]>
>> Date: 18/7/03 10:33:26
>> Subject: [USMA:26410] Air pressure history
>>
>> Dear All,
>>
>> Does anyone know the history of 'standard' air pressure of 29.92 inches
of
>> mercury (inHg) or 760 millimeters of mercury (mmHg).
>>
>> When I looked at the values that have been used previously I found:
>> One atmosphere of pressure is equivalent to:
>> 760 millimeters of mercury
>> 29.92 inches of mercury
>> 14.7 pounds per square inch (psi)
>> 1013.25 millibar (mb)
>> 34 feet of water (approximately 10 meters of water)
>>
>> Thinking that the 'standard' air pressure might be a mid-point between
>> high
>> and low pressures, I investigated to find that:
>> The lowest air pressure recorded at sea level was 87 kilopascals, and
>> the highest air pressure recorded at sea level was 108.4 kilopascal, but
>> the mid-point between these values is 97.7 kilopascals, and this doesn't
>> seem to fit with any of the previously used 'standard' values.
>>
>> I then thought that 10 metres of water might be a clue. Taking the
>> standard
>> value of acceleration due to gravity (g) as 9.806 65 metres per second
>> squared, I found that the pressure below 10 metres of water is about
>> 98 kilopascals, so I had no luck there either.
>>
>> Can anyone help with the history of 'standard' air pressure?
>>
>> Thanks,
>>
>> Pat Naughtin LCAMS
>> Geelong, Australia
