Why Does Warm Air Rise?
This is a common misconception ‘š warm air does not rise. Rather, cooler, more dense air is pulled towards the Earth more by gravity, and the warmer, less dense air is displaced and forced upwards, over the cooler air. This is a very scientifically heavy concept, but it can be explained in simpler terms.
The first thing to discuss is what is air? Air is a mixture of various gases in our atmosphere: oxygen, nitrogen, and carbon dioxide are the main and most commonly discussed. Gas molecules agitate and move around, dependant on the temperature. Heat is a type of energy, and where there is more energy, the molecules move faster and faster, which causes them to take up more space, to avoid colliding with one another. It takes up more space, but it still weighs the same as a less expanded air of the same amount of molecules. Think of unpopped popcorn being popped. The popped corn will weigh the same as the unpopped, but it will take up much more space ‘š as long as the same amount of kernels are used. If you fill a cup of unpopped corn and popped corn, and weigh them, the unpopped corn will definitely weigh more, because more kernels will fit into the cup unpopped than popped. You can say that the unpopped corn has more density than popped corn ‘š density is a function of both space and mass (weight).
This is the same as air ‘š because the warm air takes up more space, and is thus less dense, cooler air is pulled towards the ground through gravity much harder than the less dense air ‘š gravity pulls heavier objects more because there is more weight to hold onto ‘š think of a piece of iron, a piece of wood, and a feather, all of the same size ‘š the iron will fall fastest because it is heavier, and the feather will fall slowest because it is lightest. The dense air then simply displaced the less dense air, forcing it upwards.