A big, hairy Spider skitters across the floor of your room; its eight, long, rangy legs moving almost robotically. It stops. Horrified, you picture its fangs clicking together, and its many eyes jerkily twitching to and fro. Suddenly, the spider scuttles under your bed. Though you wait five minutes for it to reappear, it does not. Will you be able to sleep tonight, knowing that a monster lurks below?
So why do spiders move in this unnatural, mechanical fashion? Well, it’s because they fundamentally move differently than we do. Arachnid locomotion actually makes use of the same force that powers a variety of mechanical instruments: hydraulics.
Hydraulics is the process whereby power is generated, controlled, and transmitted through the use of pressurized liquids. A basic way to understand it is to picture two liquid-filled cylinders, each topped with a piston and connected by a pipe. If you apply pressure to one piston by pushing it down, the force transferred through the liquid to the other piston, and this piston rises with the liquid. Dump trucks, skid loaders, and pumps are all man-made machines that operate on hydraulics.
