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| Thread ID: 67493 | 2006-03-29 12:39:00 | sea level pressure | Fergie (6508) | PC World Chat |
| Post ID | Timestamp | Content | User | ||
| 441806 | 2006-03-30 02:37:00 | QUOTE...."Universally, the sea level pressure anywhere in the world is 14.7 lb/square inch." (Surfer Joe) Fortunately, the Americans have not yet taken total control of the atmosphere, no matter how much they would like to be the worlds policemen :) The 'standard' atmospheric pressure (and temperature) is just an average value, convenient to define for design purposes, actual values obviously vary considerably as already mentioned. In the same way, standard pressures and temperatures are defined for different altitudes, so when for example designing airplanes, aero engines and fuel systems, or meteorological studies, everyone is working from the same data. Years ago, that is, when I was designing jet engine fuel systems, we used standard ICAN tables for altitude, pressure, and temperature. ICAN= International Commission for air Navigation, replaced by ICAO in 1947, but the data references were still refered to as ICAN in the trade. Nowadays there is a US standard (1976)for altitude, pressure and temperature, these tables go way beyond the 60,000 feet of the old ICAN tables, but up to that altitude the values are nominally the same. www.engineeringtoolbox.com It is left as an exercise for the reader to work out the implications of a 6 metre rise in sea level due to global warming, melting of the ice caps, and what happens to the heights of all the worlds mountains. |
Terry Porritt (14) | ||
| 441807 | 2006-03-30 02:43:00 | >It is left as an exercise for the reader to work out the implications of a 6 metre >rise in sea level due to global warming, melting of the ice caps, and what >happens to the heights of all the worlds mountains. Please also don't forget what may happen if a butterfly happens to flap its wings especially when not in a forest where a tree may fall and you did not hear it. pressf1.pcworld.co.nz :-) |
Sweep (90) | ||
| 441808 | 2006-03-30 02:51:00 | Universally, the sea level pressure anywhere in the world is 14 . 7 lb/square inch . Oh no it's not . The air pressure at sea level is the weight of a column of air of "unit area" . So it depends on the gravity at the place, and the "average" density of the air, which will depend on the temperatures throughout the column . Any contents (such as smog, and water, "humidity" -- which will be affected by the temperature too) will make a difference . Gravity varies with latitude and (to a lesser degree) the geology of the place . Joe is probably thinking of Standard Temperature and Pressure (en . wikipedia . org/wiki/Standard_temperature_and_pressure) . The conditions at any place are universally not STP . :D Rarely, at a particular place, the conditions might coincidentally equal STP . |
Graham L (2) | ||
| 441809 | 2006-03-30 02:52:00 | "Fortunately, the Americans have not yet taken total control of the atmosphere, no matter how much they would like to be the worlds policemen .........." HUH?...We control atmospherics now? Gads..that's paranoid. |
SurferJoe46 (51) | ||
| 441810 | 2006-03-30 02:59:00 | "Fortunately, the Americans have not yet taken total control of the atmosphere, no matter how much they would like to be the worlds policemen .........." HUH?...We control atmospherics now? Gads..that's paranoid. Almost Joe, almost,...."U.S Standard Atmosphere Properties of US standard atmosphere, -5.000 to 250.000 ft altitude" See that link I gave :) Edit:And they are laying claim to an as yet non-existent 5000 feet below sea level, that is, for when the seas have evaporated. |
Terry Porritt (14) | ||
| 441811 | 2006-03-30 03:19:00 | The best thing about standards is that you can have so many of them. My link lists 13 STP standards in use. US organisations have perpetrated some of them. | Graham L (2) | ||
| 441812 | 2006-03-30 03:46:00 | Hey. can any one tell me (or tell me where to find - yes i've spent ages on google) the sea level pressure in NZ and the altitude of hamilton city? Thanks The Altitude in Hamilton city at the Founders Theatre is 100 feet above sea level. Move over a bit and I found 152 feet above sea level still within Hamilton City though. This seems to be the only question not answered. |
Sweep (90) | ||
| 441813 | 2006-03-30 03:53:00 | "Fortunately, the Americans have not yet taken total control of the atmosphere, no matter how much they would like to be the worlds policemen .........." HUH?...We control atmospherics now? Gads..that's paranoid. Don't forget Joe,T is a pinky and paranoia goes with that. :lol: |
Cicero (40) | ||
| 441814 | 2006-03-30 18:01:00 | Don't forget Joe,T is a pinky and paranoia goes with that. :lol: Oooooooh! PINKY here in the US is the smallest finger on your hand...and thinking that way, Yes! I can see the reason for the paranoid thoughts! After all, the other fingers are all larger/stronger and more useful than it is........er...present company EXCEPTED! of course! |
SurferJoe46 (51) | ||
| 441815 | 2006-03-30 18:38:00 | Atmospheric pressure varies all the time. It is not a constant. Standard pressure is 1013 (whatevers). It can get as low as 990 or up into the 1020's. Aircraft altimiters work by air pressure. That is why air traffic control always tells the pilot local QNH (air pressure at sea level) before take off and again when he calls control. Incorrect settings can alter the indicated altitude by up to 1000 feet.Altitude is measured in feet not meters. Above 10,000 feet standard pressure is used by all aircraft. So heights of buildings ,hills etc. can not be measured precisely by air pressure. |
JJJJJ (528) | ||
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