New World Encyclopedia integrates facts with values.
Written by online collaboration with certified experts.
The world ocean, an integral part of global climate, is constantly changing, absorbing heat from the sun and cooling through evaporation, dissolving and releasing carbon dioxide, and moving in great conveyor belt currents transferring heat and moisture toward the poles from the tropics and deep below the surface returning cold water to the tropics. From ocean breezes to monsoons, hurricanes, summer rains, and winter fog, the oceans' heat and water vapor are constantly affecting life on land, even far from the ocean shore.
Acrobats were greatly admired in ancient China, Egypt, and the Minoan civilization. Tightrope walkers were honored in ancient Rome. At fairs during the Middle Ages, tumblers performed somersaults, back flips, and other tricks to entertain large groups of people.