A thermal is a column of rising warm air that is created by the sun heating the ground. The heat causes the air above the ground to become less dense and less stable, causing it to rise. As the air rises, it cools and eventually reaches a point where it is no longer buoyant and stops rising. The rising and cooling of the air creates a circular pattern of rising warm air, called a thermal. Thermals are most commonly found in the afternoon, when the sun is at its strongest and the ground is warmest. They can be found in many places but are most commonly found in open areas such as fields, deserts and plateaus.
Thermals are a key element in soaring, especially for gliders and paragliders, as they allow the aircraft to gain altitude without the use of an engine. Pilots look for thermals by scanning the sky for clouds, dust devils or other signs of rising air, and then fly in circles around the thermal to gain altitude.
Thermals are also important for other forms of flying, such as hang gliding and paragliding. These forms of flying can also use thermals to gain altitude and extend the flight time.
