Substances on Earth’s surface absorb light energy from the sun. This energy causes particles to move, which leads to increases in their thermal energy, then increases in their temperature. Warmed substances on Earth’s surface transfer thermal energy to air molecules that collide with the surface by conduction. These rising warm air molecules then create a convection current in the air. This explains
why hot air rises. As substances on Earth's surface absorb light energy from the sun, their particles become energized and start to move more vigorously. This increase in movement leads to an increase in their thermal energy, which in turn raises their temperature.
When substances on Earth's surface are warmed, they transfer their thermal energy to the surrounding air molecules through a process called conduction. The hot substances transfer some of their thermal energy to the air molecules that come into direct contact with them. This transfer of energy causes the air molecules to gain kinetic energy and also start moving more rapidly.
As the warmed air molecules gain energy and move faster, they become less dense than the surrounding cool air. This decrease in density causes the warm air to rise and the cool air to sink. This movement of warm air upwards and cool air downwards creates a convection current in the air.
The convection current continues as long as there is a temperature difference between the warmed surface and the surrounding air. This process is the reason why hot air rises. It is also the mechanism behind many atmospheric phenomena, such as the formation of clouds and the circulation of air masses in the atmosphere.