Atmospheric pressure
Query URLs
https://term.museum-digital.de/md-de/tag/33665
- Note
- Atmospheric pressure, also known as air pressure or barometric pressure (after the barometer), is the pressure within the atmosphere of Earth. The standard atmosphere (symbol: atm) is a unit of pressure defined as 101,325 Pa (1,013.25 hPa), which is equivalent to 1,013.25 millibars, 760 mm Hg, 29.9212 inches Hg, or 14.696 psi. The atm unit is roughly equivalent to the mean sea-level atmospheric pressure on Earth; that is, the Earth´s atmospheric pressure at sea level is approximately 1 atm.
In most circumstances, atmospheric pressure is closely approximated by the hydrostatic pressure caused by the weight of air above the measurement point. As elevation increases, there is less overlying atmospheric mass, so atmospheric pressure decreases with increasing elevation. Because the atmosphere is thin relative to the Earth´s radius—especially the dense atmospheric layer at low altitudes—the Earth´s gravitational acceleration as a function of altitude can be approximated as constant and contributes little to this fall-off. Pressure measures force per unit area, with SI units of pascals (1 pascal = 1 newton per square metre, 1 N/m2). On average, a column of air with a cross-sectional area of 1 square centimetre (cm2), measured from the mean (average) sea level to the top of Earth´s atmosphere, has a mass of about 1.03 kilogram and exerts a force or "weight" of about 10.1 newtons, resulting in a pressure of 10.1 N/cm2 or 101 kN/m2 (101 kilopascals, kPa). A column of air with a cross-sectional area of 1 in2 would have a weight of about 14.7 lbf, resulting in a pressure of 14.7 lbf/in2.
-
Barometer
Es handelt sich um ein...
Object information
Image: Städt. Hellweg-Museum Geseke - CC BY-NC-SA -
Aneroid-Barometer
Das Barometer wurde um 1900...
Object information
Image: Spengler-Museum - CC BY-NC-SA -
Wetterglas
Das dickwandige Wetterglas...
Object information
Image: Kulturstiftung Sachsen-Anhalt - CC BY-NC-SA -
Schiffsbarometer
Ein Barometer ist ein...
Object information
Image: Binnenschifffahrts-Museum Oderberg - CC BY-NC-SA -
Hypsometer
Das Messgerät ist Teil der...
Object information
Image: Museum Baruther Glashütte - CC BY-NC-SA
References
[]