No concept of physics has been more theorized, debated, or ridiculed more readily than the idea of a perpetual motion machine – a device that physicists and inventors have hoped to build since the study of physics began. The history of perpetual motion machines is a long and colorful one, filled with scientists adamant that such a machine can never be made on one hand, and pioneering scientists who have attempted to build such machines. There are two definitions of a perpetual motion – the first contradicts the laws of conservation of mass/energy — though the second is theoretically possible. However, such a machine only derives it’s usefulness from the ability to manipulate the machines energy from an outside source. This paper will examine the history of perpetual motion machines, their feasibility, and their theoretical real world applications.
Perpetual motion and perpetual motion machines fall under several different definitions. The term is used interchangeably to describe a machine that exhibits several different phenomena. One definition describes a perpetual motion machine as a device that puts out more energy and mass that it takes it. This definition contradicts Newton’s first law of thermodynamics and the law of conservation of energy. A second definition of a perpetual motion machine describes a device that operates indefinitely without receiving added energy from an outside source. In essence, a perpetual motion machine that follows this definition would be its own infinitely recyclable power plant of energy. A type of machine that follows this description is much more feasible than the first type; however, the great majority mainstream scientists attest that even these types of machine are only possible in theory not practice.
Since the 13th century, scientists and inventor have tried to design machines that would run indefinitely or produce more work than allowed by the laws of physics. Leonardo da Vinci a painter, inventor, and thinker known for his designs of inventions years before their times, sketched a number of drawings detailing perpetual motion machines.
Mainstream scientists attest that the main reason that perpetual motion machines don’t exist is the law of conservation of mass which states energy cannot be created or destroyed. Similarly, they argue that because of resistance forces such as friction and air resistance, a machine that outputs 100% of the energy input is impossible at a practical standpoint. Friction is an inescapable variable of the universe, and any two bodies that collide in any space will be affected by friction. Several different machines have been designed trying to combat this perspective; however, they have had mixed results.
A simple perpetual motion machine was designed by renowned Professor Feynman to show the impossibility of perpetual motion. For his theorized machine, a ratchet mechanism means that the shaft can only turn in one direction. Random motions in the gas will cause atoms to bombard the fins. “Statistical fluctuations make it likely that at some point there will be more impacts on one side of the fins than on another. If this happens then the shaft will be turned. However, the ratchet means that the shaft can only turn in one direction. Thus, the wheel will turn in only one direction forever and can be used to generate power.” A design like this is sound in theory; however, in practice perpetual motion with this machine still could not be achieved.
The principle flaw with the machine is in the ratchet mechanism. A typical ratchet consists of a peg on a spring held against a gear made with a serrated tooth that is sharply inclined in one direction and shallowly inclined in another. As the ratchet of Feynman’s device operates, the gear’s teeth will heat up slightly as a response to the pegs bouncing off the gear’s teeth. Energy will be lost due to that heat.
Those who consider perpetual motion a possibility argue that planets orbiting in space are really large scale perpetual motion machines. Detractors respond in two ways. In space something in motion will stay in motion for an almost indefinite amount of time due to the nature of the vacuum. However, as a result of microscopic cosmic debris from asteroids, planets and other bodies, there are an insignificant amount of stray particles in space. If giving enough time, the effect of these particles bouncing off of the body in motion will slow that body, thus halting the body from achieving perpetual motion.
