Conduction
Topic: Solar Radiation, Heat Balance and Temperature · NCERT: Class 11, Ch 8 "Solar Radiation, Heat Balance and Temperature"
Meaning
Conduction is the passing of heat between two bodies that touch, from the warmer one to the cooler one. It goes on until both have the same temperature or they stop touching. In the atmosphere, the ground heats or cools only the thin layer of air resting on it. Air is a poor conductor, so conduction matters only very close to the surface.
Example
On a summer afternoon in the Thar Desert of Rajasthan, the hot sand heats the air touching it, so the air just above the ground becomes very hot. On clear winter nights in the north Indian plains, the cold ground cools the air touching it. This can form dew, frost or fog.
Don't confuse with
- Convection: convection carries heat upward through the air in rising currents. Conduction works only where things touch, so it affects only the thin layer of air on the ground.