Which term refers to a rising column of air that can generate lift for gliders and light aircraft?

Which term refers to a rising column of air that can generate lift for gliders and light aircraft?

• A. Vortex
• B. Wind
• C. Upwash
• D. Thermal

Answer: (D)

Rising columns of warm air that can lift a glider are called thermals. They form when the sun heats the ground, warming the air near the surface so it becomes buoyant and rises through cooler air above. A pilot seeking altitude will move into a thermal and fly in tight circles to stay within the updraft, trading airspeed for altitude as the warm air continues to rise. This mechanism is distinct from a vortex (a swirling air pattern around a wing or rotor), wind (any moving air), or upwash (the upward component of air over a wing, not a standalone rising column). Thermals are the practical source of lift that gliders rely on to stay aloft for extended flight.

Rising columns of warm air that can lift a glider are called thermals. They form when the sun heats the ground, warming the air near the surface so it becomes buoyant and rises through cooler air above. A pilot seeking altitude will move into a thermal and fly in tight circles to stay within the updraft, trading airspeed for altitude as the warm air continues to rise. This mechanism is distinct from a vortex (a swirling air pattern around a wing or rotor), wind (any moving air), or upwash (the upward component of air over a wing, not a standalone rising column). Thermals are the practical source of lift that gliders rely on to stay aloft for extended flight.