|
|
Convection
Convection, from the Latin /con/ meaning against or away, and /vect/
meaning "move," is when heat is transferred away from a mass (liquid or
gas). For instance, the sunlight heats the Earth's surface, some of the
heat is transferred to the air by conduction, and the heated air becomes
less dense and therefore rises, carrying heat away with it. Rising heated
pockets of air are called "thermals." As a thermal rises, denser cooler
air sinks down and moves into the heater region. this leads to the formation
of a "cell," or a region of convective circulation. The horizontally moving
part of the circulation, called "wind," carries air properties with it,
and the transfer of these properties is called advection. For instance,
if the wind blows over a body of water it may pick up water vapor and transport
it. If the air then cools the vapor may condense and advective fog may
occur.
|
|
