Pascal’s Principle
Developed by French mathematician Blaise Pascal, Pascal’s Principle states that: “any change in pressure applied to a completely enclosed fluid is transmitted undiminished to all parts of the fluid and the enclosing walls”. This means that the pressure is the same throughout the entire system. This is what allows a small force on a small piston can move a much larger piston, as used in a hydraulic car lift. Since the pressure is the same throughout the system, the pressure (force over area) at both ends will also be the same. As the area at the car end is larger, the force must also be larger. The ratio between areas will be the same as the ratio between the forces. This ratio is also the extra distance that the small piston needs to travel to be able to move the second.