|1.||Compare conduction a process of heat transfer through a gas or liquid by bulk motion of hotter material into a cooler region|
|2.||meteorol the process by which masses of relatively warm air are raised into the atmosphere, often cooling and forming clouds, with compensatory downward movements of cooler air|
|3.||geology the slow circulation of subcrustal material, thought to be the mechanism by which tectonic plates are moved|
|[C19: from Late Latin convectiō a bringing together, from Latin convehere to bring together, gather, from vehere to bear, carry]|
|convection (kən-věk'shən) Pronunciation Key
Current in a fluid caused by uneven distribution of heat. For example, air on a part of the Earth's surface warmed by strong sunlight will be heated by contact with the ground and will expand and flow upward, creating a region of low pressure below it; cooler surrounding air will then flow in to this low pressure region. The air thus circulates by convection, creating winds. See Note at conduction.
The motion of warm material that rises, cools off, and sinks again, producing a continuous circulation of material and transfer of heat. Some examples of processes involving convection are boiling water, in which heat is transferred from the stove to the air; the circulation of the atmosphere of the Earth, transferring heat from the equator to the North Pole and South Pole; and plate tectonics, in which heat is transferred from the interior of the Earth to its surface.