Static buoyancy in gases

How is buoyancy generated?

As in liquid substances, a body is also affected by pressure from all sides in gases (i.e. air) (see picture below). The pressure of the air decreases with height, because the density of the air decreases. The forces which are acting from the opposite sides are equal because they are each acting in the same height. Therefore the lateral forces cancel each other out and we do not have to consider them in our further reflections.

The force which is directed vertically downwards F₁, is smaller than the counteracting force F₂. The difference of F₂ and F₁ is called the static buoyancy (F_A ).