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:
“Esteem must be founded on preference: to hold everyone in high esteem is to esteem nothing.”
—Molière [Jean Baptiste Poquelin] (1622–1673)
“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)
“Converse with a mind that is grandly simple, and literature looks like word-catching. The simplest utterances are worthiest to be written, yet are they so cheap, and so things of course, that, in the infinite riches of the soul, it is like gathering a few pebbles off the ground, or bottling a little air in a phial, when the whole earth and the whole atmosphere are ours.”
—Ralph Waldo Emerson (1803–1882)
“Much of the pressure contemporary parents feel with respect to dressing children in designer clothes, teaching young children academics, and giving them instruction in sports derives directly from our need to use our children to impress others with our economic surplus. We find “good” rather than real reasons for letting our children go along with the crowd.”
—David Elkind (20th century)