This lesson is divided into three activities. The first activity focuses on learning how air temperature affects air pressure. Heating of the earth, which in turn heats the atmosphere, is responsible for the motions and movements of the air in the atmosphere. Air like most other substances, expands when heated and contracts when cooled.
Heat travels by convection, meaning warm air rises .
The faster molecules move, the hotter the air. As the molecules heat and move faster, they are moving apart. Because there is more space between the molecules, the air is less dense than the surrounding matter and the hot air floats upward. This is the concept used in the hot air balloons. The air is heated by the burner and the expanding air causes the balloon to rise through the denser, cooled air.