Pascal's Law

Pascal's law states that "Pressure exerted by liquid in an enclose vessel is transmitted equally". This law was formulated by Blaise Pascal who was born in 1623 in France. This law is applicable for the gases also. The verification of Pascal's law can be done with this simple experiment:

Take a plastic (or a balloon) and poke small holes (carefully) in the plastic. Fill the plastic with water and seal the top big opening. Slowly press the plastic from the top and watch how water flows through each hole. Water should flow equally from all the pores because the pressure applied from the top is distributed equally to all the holes.

Hydraulic press

This is an equipment based on Pascal's law. To create hydraulic press we need two or more pistons, of different cross section area, along with water or oil. A structure is made as shown in the picture and liquid is added into it. Then the pistons of matching size are inserted in the opening and the openings are sealed. The openings are sealed in such a way that the pistons are allowed to move freely pressing the liquid. When small piston is pressed the pressure is distributed equally in the liquid. So the larger piston will move upward. According to the Pascal's law, pressure in the small piston is equal to the pressure on the larger piston.

i.e. P1 = P2

or, =

or, F₂ =

or, F₂ = F₁ x ratio of larger piston to smaller piston.

This shows more the area of the ratio of larger piston to smaller piston the force will be bigger. The same law is applied in hydraulic brakes and hydraulic lifts.