A perpetual motion machine can gain unlimited power without consuming any natural resources.
Rumors:
The application of science and technology in production and life has liberated mankind from heavy physical labor, but it also consumes a lot of energy and motivation. So people dream of inventing a machine that can continuously output energy or power without consuming any external energy. People once imagined that if we could make it a perpetual motion machine, we could get unlimited power without consuming any natural resources. This is indeed an extremely tempting fantasy! For a long time, many people have devoted themselves to the research and development of perpetual motion machines. But so far, no perpetual motion machine has been tested successfully. What is the reason?
With the progress of natural science, we know that the idea of perpetual motion machine is against the basic laws of thermodynamics, so it is impossible to realize it. The four basic laws of thermodynamics are the most solid laws in natural science and the crystallization of science, technology and experience for hundreds of years. So far, we haven't found any cases that violate the basic laws of thermodynamics.
People's imaginary perpetual motion machines can be divided into two categories: the first category is perpetual motion machines that violate the first law of thermodynamics, and the second category is perpetual motion machines that violate the second law of thermodynamics. So, why can't these two kinds of perpetual motion machines be realized?
The perpetual motion diagram designed by Leonardo da Vinci
Perpetual machine violating the first law of thermodynamics
The first law of thermodynamics (that is, the law of conservation and transformation of energy) reveals: "The energy of substances in nature can be transformed from one form to another, and can also be transferred from one object to another, but the total energy remains unchanged during the transformation or transfer." The working principle of "perpetual motion machine of the first kind" is that it can do work without consuming energy, which is contrary to the first law. The masterpiece of this perpetual motion machine is Da? The perpetual motion machine designed by Finch hopes to use moment of force to make the wheels rotate around the central axis, which can continuously output power. However, at a certain position, because the moments generated by all spheres can just cancel each other out, the device can't realize the imaginary "perpetual motion machine" at all. In the following time, a large number of experiments to make the first kind of perpetual motion machine, which should have used buoyancy, electromagnetic force, inertia force or capillary action, failed one after another. As early as 1586, Steven, a Dutch scientist, clearly pointed out in his book Fundamentals of Statics that a perpetual motion machine could not be made by mechanical means.
1775, based on the fact that theory and practice proved that the perpetual motion machine of the first kind could not be realized, the French Academy of Sciences passed a resolution and refused to try "any machine showing perpetual motion machine".
Perpetual machine violating the second law of thermodynamics
The second kind of perpetual motion machine is a device that gets a certain power from only one kind of energy and runs forever. The masterpiece of this perpetual motion machine is the "zero-degree engine" designed by American inventor Gammel, which uses liquid ammonia as working medium. The working principle of the device is that liquid ammonia absorbs heat from the surrounding environment, expands after vaporization, pushes the piston, outputs driving force, and then automatically condenses to release heat to the surrounding environment. During the whole cycle, energy is conserved and does not violate the first law. Moreover, due to energy conversion, the output work is finally released into the environment in the form of heat, so that the energy of the environment can be inexhaustible. If you repeat the above process, you can continue to work. This design seems to be feasible, but it violates the second law of thermodynamics. So, of course, the experiment didn't succeed, which is also an unrealistic fantasy.
The second law of thermodynamics reveals that it is impossible to obtain heat from a single heat source and completely convert it into work without affecting the environment. The second law of thermodynamics emphasizes the directionality of heat transfer process. Although heat can be spontaneously transferred from a high-temperature object to a low-temperature object, this transfer process must consume some work. Gammy's "zero-degree engine" is a machine that obtains heat from a single heat source and converts it into work. The process of absorbing heat from high temperature environment and vaporizing liquid ammonia can be spontaneous, but the condensation and exothermic process of gaseous ammonia cannot be realized spontaneously. It must have a cold source lower than the ambient temperature, and it needs to consume a certain amount of energy to maintain this cold source, so the "perpetual motion machine" of the device is also impossible.
Resolution of French Academy of Sciences on perpetual motion machine
1775, the French academy of sciences passed a resolution very solemnly, that is, it would never accept the application of perpetual motion machines. The book History of the French Academy of Sciences has the following record: "This year, the Academy of Sciences passed a resolution and decided to refuse to listen to the answers to the following questions: cubes, angles, squares with the same area as circles, and any machines that show eternal motion." And make the following explanations: it is absolutely impossible to build a perpetual motion machine, even if the friction and resistance in the middle will not destroy the original power eventually, this power will not produce the same effect as the original; For another example, assuming that power can work continuously, its role will be infinitely small in a certain period of time. If the friction and resistance decrease, the initial motion may often continue, but it cannot act on other objects. Under this assumption (nature can't exist), the only possible eternal motion is useless for realizing the purpose of the perpetual motion builder.
After the establishment of the thermodynamic system, it is proved by careful logical reasoning and research that the perpetual motion machine violates the basic principles of thermodynamics. At present, the United States Patent and Trademark Office also prohibits granting patent certificates to applications such as perpetual motion machines.
Judging expert: Zhang Chuang, former deputy director of Institute of High Energy Physics, Chinese Academy of Sciences, and director of Science Popularization Committee of Chinese Physics Society.