Difference Between

Gay-Lussac Law vs Pascal Principle
 

Gay-Lussac law and Pascal principal are two important concepts discussed in physics. Gay-Lussac law is widely used to describe the properties of gases. Pascal principle describes some properties of fluids. Pascal principle is applied in fields such as fluid mechanics, hydraulic engineering, fluid statics etc. It is also applied in many real world applications such as hydraulic jack, hydraulic press, and force amplifiers in the breaking system of most motor vehicles, artesian well, water towers and dams. It is vital to have a proper understanding in Gay-Lussac law and Pascal principle in order to excel in such fields. In this article, we are going to discuss what Gay-Lussac law and Pascal principle are, their definitions, similarities, applications, and finally the difference between Gay-Lussac law and Pascal law.

Gay-Lussac Law

Gay-Lussac law was proposed by the French chemist Joseph Louis Gay-Lussac. There are two relationships of Gay-Lussac law. One is called law of combining volumes and the other one is called pressure-temperature law. The law of combining volumes states that when gases react together to form other gases, the ratio between the volumes of the reactant gases and products can be expressed in simple whole numbers. For this, all volumes must be measured at the same pressure and temperature. The Gay-Lussac law shows that 1 volume of chlorine and 1 volume of hydrogen would react to form 2 volumes of gaseous hydrochloric acid. In pressure-temperature law, it states that the pressure of a gas of fixed mass and a fixed volume is directly proportional to the absolute temperature of the gas. The law can then be expressed mathematically as P α T, or P/T = k, where the pressure of the gas (measured in atm) is denoted by P, temperature of the gas (measured in Kelvin) is denoted by T, and k is a constant. When the same substance is considered under two different sets of conditions, this law is given by the equation P₁/T₁ = P₂/T₂.

Pascal Principle

Pascal principle was put forward by the French mathematician Blaise Pascal. Pascal principle states that when pressure is increased at any point in a confined incompressible fluid, there is an equal increment of the pressure at every other point in the container. This law can be expressed mathematically as ΔP = ρg(Δh); where hydrostatic pressure(given by pascals) is denoted by ΔP, fluid density is denoted by ρ, acceleration due to the gravity is denoted by g, and height of the fluid above the point of measurement is denoted by (Δh). A common application of the Pascal principle is the hydraulic jack, which is used to raise a car off the ground. Here, a small force is applied to a small-area piston. That small force is then transformed to a large force at a large area piston. When the car sits on the top of the large piston, it can be lifted by applying a relatively small force to the smaller piston.