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:
“I had a thought for no one’s but your ears:
That you were beautiful, and that I strove
To love you in the old high way of love;
That it had all seemed happy, and yet we’d grown
As weary-hearted as that hollow moon.”
—William Butler Yeats (1865–1939)
“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)
“I date the end of the old republic and the birth of the empire to the invention, in the late thirties, of air conditioning. Before air conditioning, Washington was deserted from mid-June to September.... But after air conditioning and the Second World War arrived, more or less at the same time, Congress sits and sits while the presidents—or at least their staffs—never stop making mischief.”
—Gore Vidal (b. 1925)
“By school age, many boys experience pressure to reveal inner feelings as humiliating. They think their mothers are saying to them, “You must be hiding something shameful.” And shucking clams is a snap compared to prying secrets out of a boy who’s decided to “clam up.””
—Ron Taffel (20th century)