Pascal's law: the pressure is equal to the applied pressure divided by the stressed area, which is expressed as F 1/S 1=F2/S2.

Due to the fluidity of liquid, the pressure change of a certain part of static fluid in a closed container will be transmitted in all directions without change. In the closed container shown in the above figure, if a certain pressure is applied to the small piston, it will be transmitted to the other piston along the pipeline, resulting in the same pressure increase. If the area of the second piston is 10 times that of the first piston, the force acting on the second piston will increase to 10 times that of the first piston.