High Altitude and Low Air Pressure
Regions on the Earth's surface (or in its atmosphere) that are high above mean sea level are referred to as high altitude. High altitude is sometimes defined to begin at 2,400 metres (8,000 ft) above sea level.
At high altitude, atmospheric pressure is lower than that at sea level. This is due to two competing physical effects: gravity, which causes the air to be as close as possible to the ground; and the heat content of the air, which causes the molecules to bounce off each other and expand.
Because of the lower pressure, the air expands as it rises, which causes it to cool. Thus, high altitude air is cold, which causes a characteristic alpine climate. This climate dramatically affects the ecology at high altitude.
Read more about this topic: Altitude
Famous quotes containing the words high, altitude, air and/or pressure:
“It is not their bones or hide or tallow that I love most. It is the living spirit of the tree, not its spirit of turpentine, with which I sympathize, and which heals my cuts. It is as immortal as I am, and perchance will go to as high a heaven, there to tower above me still.”
—Henry David Thoreau (1817–1862)
“On a level plain, simple mounds look like hills; and the insipid flatness of our present bourgeoisie is to be measured by the altitude of its “great intellects.””
—Karl Marx (1818–1883)
“There is something about poverty that smells like death. Dead dreams dropping off the heart like leaves in a dry season and rotting around the feet; impulses smothered too long in the fetid air of underground caves. The soul lives in a sickly air. People can be slave-ships in shoes.”
—Zora Neale Hurston (1891–1960)
“Adolescence is when girls experience social pressure to put aside their authentic selves and to display only a small portion of their gifts.”
—Mary Pipher (20th century)