Hydraulics use the power of water pressure to move large lodes. Hydraulics are metal tubes, inside the metal tube is a cylinder with a flat circular end that creates a water tight seal. The tube has three opening, two of the opening are for hydraulic fluid to flow in and out to make the cylinder move, the third hole is for what ever the cylinder is connected to.
This is important to engineering because it allows us to move items that weigh more than a normal human lift. It also allows us to lift materials a greater height than we could with primitive technology.
for more information go to http://www.explainthatstuff.com/hydraulics.html
