Hydrostatic pressure and air pressure

hydrostatic pressure is the pressure that is created within a resting fluid under the influence of weight. Hydrostatic pressure within a fluid grows with the depth of immersion.

air pressure is the hydrostatic pressure of air. It is generated by the weight of the air column that is located above a body or the earth surface.

hydrostatic pressure can be calculated by:

p = ρ ⋅ g ⋅ h

Hierbei ist
p - hydrostatic pressure
ρ - Density of a fluid or gas
g - gravitational force (9,81 m/s²)
h - height of the air column

It is evident:
density of water: 1 kg/dm³ bzw. 1 kg/Liter
density of air: 1,2 g/dm³ bzw. 1,2 g/Liter

pressure takes effect in every direction and the forces act both upwards and downwards as well as to the sides.