Atmospheric pressure - Revision history

Joceil.infante at 03:24, 21 March 2017

2017-03-21T03:24:54Z

Joceil.infante at 03:16, 21 March 2017

2017-03-21T03:16:19Z

Joceil.infante at 02:58, 21 March 2017

2017-03-21T02:58:38Z

Joceil.infante at 02:52, 21 March 2017

2017-03-21T02:52:59Z

Joceil.infante at 08:57, 9 February 2017

2017-02-09T08:57:34Z

Joceil.infante: /* References */

2017-02-09T01:11:39Z

‎References

Joceil.infante: /* References */

2017-02-09T01:10:03Z

‎References

Joceil.infante: /* References */

2017-02-09T01:09:54Z

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Joceil.infante: Created page with "'''Atmospheric pressure''' is also called the '''barometric pressure''' and varies with elevation above sea level. Also, at a given place it varies slightly from time to time..."

2017-02-09T01:09:28Z

Created page with "'''Atmospheric pressure''' is also called the '''barometric pressure''' and varies with elevation above sea level. Also, at a given place it varies slightly from time to time..."

New page

'''Atmospheric pressure''' is also called the '''barometric pressure''' and varies with elevation above sea level. Also, at a given place it varies slightly from time to time because of changes in meteorological conditions.

It is the force exerted on a surface by the air above it as gravity pulls it to earth. Atmospheric pressure is commonly measured with a barometer. In a barometer, a column of mercury in a glass tube rises or falls as the weight of the atmospheric changes. Meteorologists describe the atmospheric pressure by how high the mercury rises.

Atmosphere (atm) is a unit of measurement equal to the average air pressure at sea level at a temperature of 15 degrees Celsius (59 degrees Fahrenheit). One atmosphere is 1.013 milibars, or 760 millimeters (29.92 inches) of mercury.

Atmospheric pressure drops as altitude increases. The atmospheric pressure on Denali, Alaska, is about half that of Honolulu, Hawai'i. Honolulu is a city at sea level. Denali, also known as Mount McKinley, is the highest peak in North America.
As the pressure decreases, the amount of oxygen available to breathe also decreases. At very high altitudes, atmospheric pressure and available oxygen get so low that people can become sick and even die.

Mountain climbers use bottled oxygen when they ascend very high peaks. They also take time to get used to the altitude because quickly moving from higher pressure to lower pressure can cause decompression sickness. Decompression sickness, also called "the bends", is also a problem for scuba divers who come to the surface too quickly.

Aircraft create artificial pressure in the cabin so passengers remain comfortable while flying.

Atmospheric pressure is an indicator of weather. When a low-pressure system moves into an area, it usually leads to cloudiness, wind, and precipitation. High-pressure systems usually lead to fair, calm weather.

== References ==

@@ Line 1: / Line 1: @@
 [[File:Atmospheric pressure mb heights.jpg|thumb|200px]]
+[[File:Atmospheric Pressure.jpeg|thumb|200px]]
 It is the force exerted on a surface by the air above it as gravity pulls it to earth. Atmospheric pressure is commonly measured with a barometer. In a barometer, a column of mercury in a glass tube rises or falls as the weight of the atmospheric changes. Meteorologists describe the atmospheric pressure by how high the mercury rises.
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 In siphonic system, local atmospheric pressure (which depends on elevation above sea level and meteorological conditions) is used to determine the allowable negative pressure. Standard atmospheric pressure at sea level and 15°C is equivalent to a value of H_"o"  of about 10.3 m water head.
 The negative pressure below which cavitation can occur in the pipework of a siphonic system depends on the velocity of the flow, the degree of turbulence in the flow, the value of atmospheric pressure, and the vapour pressure at the relevant temperature of the rainwater.

@@ Line 1: / Line 1: @@
 [[File:Atmospheric pressure mb heights.jpg|thumb|200px]]
 It is the force exerted on a surface by the air above it as gravity pulls it to earth. Atmospheric pressure is commonly measured with a barometer. In a barometer, a column of mercury in a glass tube rises or falls as the weight of the atmospheric changes. Meteorologists describe the atmospheric pressure by how high the mercury rises.
@@ Line 9: / Line 10: @@
 In siphonic system, local atmospheric pressure (which depends on elevation above sea level and meteorological conditions) is used to determine the allowable negative pressure. Standard atmospheric pressure at sea level and 15°C is equivalent to a value of H_"o"  of about 10.3 m water head.
-  - local atmospheric pressure measured above vacuum, expressed as equivalent head of water, in metres (m)
+ - local atmospheric pressure measured above vacuum, expressed as equivalent head of water, in metres (m).
 The negative pressure below which cavitation can occur in the pipework of a siphonic system depends on the velocity of the flow, the degree of turbulence in the flow, the value of atmospheric pressure, and the vapour pressure at the relevant temperature of the rainwater.
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 # Fluid Mechanics with Engineering Applications by Robert L. Daugherty, Joseph B. Franzini, E. John Finnemore (p.29)
 # http://www.srh.noaa.gov/jetstream/atmos/pressure.html
-# http://www.as.wvu.edu/~rbrundage/chapter13a/sld011.htm
+# http://www.as.wvu.edu/~rbrundage/chapter13a/sld011.html

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 '''Atmospheric pressure''' is also called the '''barometric pressure''' and varies with elevation above sea level. Also, at a given place it varies slightly from time to time because of changes in meteorological conditions.
 == References ==
 # http://www.nationalgeographic.org/encyclopedia/atmospheric-pressure/
 # Fluid Mechanics with Engineering Applications by Robert L. Daugherty, Joseph B. Franzini, E. John Finnemore (p.29)

← Older revision		Revision as of 02:52, 21 March 2017
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		+	[[File:Atmospheric pressure mb heights.jpg\|thumb\|200px]]
		+
	It is the force exerted on a surface by the air above it as gravity pulls it to earth. Atmospheric pressure is commonly measured with a barometer. In a barometer, a column of mercury in a glass tube rises or falls as the weight of the atmospheric changes. Meteorologists describe the atmospheric pressure by how high the mercury rises.		It is the force exerted on a surface by the air above it as gravity pulls it to earth. Atmospheric pressure is commonly measured with a barometer. In a barometer, a column of mercury in a glass tube rises or falls as the weight of the atmospheric changes. Meteorologists describe the atmospheric pressure by how high the mercury rises.

← Older revision		Revision as of 01:11, 9 February 2017
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	1. http://www.nationalgeographic.org/encyclopedia/atmospheric-pressure/		1. http://www.nationalgeographic.org/encyclopedia/atmospheric-pressure/

−	2. Fluid Mechanics with Engineering Applications (p.29)	+	2. Fluid Mechanics with Engineering Applications by Robert L. Daugherty, Joseph B. Franzini, E. John Finnemore (p.29)

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 == References ==
 . http://www.nationalgeographic.org/encyclopedia/atmospheric-pressure/
 . Fluid Mechanics with Engineering Applications (p.29)

← Older revision		Revision as of 01:09, 9 February 2017
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	== References ==		== References ==
		+	1. http://www.nationalgeographic.org/encyclopedia/atmospheric-pressure/
		+	2. Fluid Mechanics with Engineering Applications (p.29)