The Laws of Physics Behind Hydraulics


Countless common objects that we use in our daily lives are powered by hydraulics, from toys such as water pistols to transportation like the brakes of a car. But for such an essential component of our routines, few people are familiar with this physics phenomenon and what the term actually means.

Simply put, hydraulics is the movement of liquids.

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Liquids are materials that can be compressed, although to do so involves a large amount of pressure. The reverse of this pressure can be harnessed for many useful functions, and the technology that uses this force is known as hydraulics.

Hydraulics systems are made of two pistons. The master piston is where pressure is applied. The location where the pressure is transmitted to is known as the slave piston. With this system in place, a small force applied over a large distance to the master piston can result in a large force over a small distance experienced on the other end by the slave piston. This principle is the force behind hydraulic lifts when applied on a large scale.

This phenomenon can be explained by Pascal’s Principle, which states that pressure applied to a liquid within a closed container will be expressed without loss to all components of the liquid.