The word for “machine” comes from the Greek word meaning “to help make things easier.” A machine is an object or mechanical device that receives an input amount of work and transfers the energy to an output amount of work. For an ideal machine, the input work and output work are always the same. A simple machine is a mechanical device that changes the magnitude or direction of the force. A machine is a thing that is created by people to make work easier. It is a tool or invention which multiplies the effect of human effort. The machine produces a mechanical advantage. Often a machine will change one form of energy to another form of energy. Simple machines increase or change the direction of a force. Levers, gears, pulleys, wedges, and screws are some examples of machines. Energy is still conserved for these devices because a machine cannot do more work than the energy put into it.