convection con·vec·tion (kən-věk'shən)
n.
Heat transfer in a gas or liquid by the circulation of currents from one region to another.
Fluid motion caused by an external force such as gravity.
convection (kən-věk'shən) 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.