An unachievable engine that violates the basic laws of thermodynamics. A machine that does not consume energy and can work forever, it violates the first law of thermodynamics, so it is called "the first type of perpetual motion machine." In the absence of temperature difference, the machine that continuously absorbs heat from seawater or air in nature and continuously converts it into mechanical energy violates the second law of thermodynamics, so it is called "the second type of perpetual motion machine".
The idea of perpetual motion originated in India. Around 1200 AD, this idea was passed from India to the Islamic world and passed from here to the West.
In Europe, one of the most famous early-war designs in the early days was proposed by a Frenchman named Hennessel in the thirteenth century. As shown in the figure: there is a rotating shaft in the center of the wheel, and 12 movable short rods are mounted on the edge of the wheel, and one end of each short rod is equipped with an iron ball. The designer of the scheme believes that the ball on the right is farther from the axis than the ball on the left, so the ball on the right produces a larger rotational moment than the ball on the left. This way the wheel will never stop rotating in the direction indicated by the arrow and drive the machine to rotate. This design has been copied by many people in different forms, but it has never achieved a non-stop rotation.
A careful analysis will happen. Although the torque generated by each ball on the right is large, the number of balls is small. The torque generated by each ball on the left is small, but the number of balls is large. Therefore, the wheel does not continue to rotate and does work externally. It only swings a few times and stops at the position drawn in the picture on the right.
Since the Gothic era, there have been more and more such designs. In the 17th and 18th centuries, various perpetual motion design schemes were proposed, including the use of "spiral water purifiers", which utilized the inertia of the wheels, the buoyancy or capillary action of water, and the use of repulsion between the same magnetic poles. of. The court gathered a variety of graphic designers who attempted to make money with this illusory invention. Both educated and unskilled people believe that perpetual motion is possible. This task appealed to researchers like a mirage, but all of these programs ended in failure without exception. They have been spinning around in place for many years, and they have not produced any results. Through continuous practice and experimentation, people gradually realize that any machine that consumes work on the outside world consumes energy. Without energy consumption, the machine can't do work. At this time, some well-known scientists, Stavin and Huygens, began to realize that it is impossible to make a perpetual motion machine by mechanical methods.
In the middle of the 19th century, a series of scientists made great contributions to the correct understanding of the transformation of thermal function and other forms of material movement. Soon after, great energy conservation and transformation laws were discovered. It is recognized that all matter in nature has energy. There are different forms of energy that can be transformed from one form to another, from one object to another, in the process of transformation and transmission. The sum remains the same. The law of conservation of energy conservation provides a more accurate and richer scientific foundation for dialectical materialism. It has effectively attacked the idealist views that believe that material movements can be created and destroyed at will, which completely broke the perpetual dreams.
After all attempts to make the first type of perpetual motion failed, some people dreamed of making another perpetual motion machine, hoping that it would not violate the first law of thermodynamics, and that it would be economical and convenient. For example, such a heat engine can draw heat directly from the ocean or the atmosphere to completely transform it into mechanical work. Because the energy of the ocean and the atmosphere is inexhaustible, this kind of heat engine can never stop working, and it is also a perpetual motion machine. As shown on the left:
However, based on a large amount of practical experience, the British physicist Kelvin proposed a new universal principle in 1851: it is impossible for matter to extract heat from a single heat source, making it completely useful and without other effects. In this way, the idea of the second type of perpetual motion is also bankrupt.
The idea of perpetual motion has lasted for hundreds of years in human history. The refutation of this myth is not only conducive to people's correct understanding of science, but also to people's correct understanding of the world.
Energy can neither be produced out of thin air nor disappeared from the air. It can only be transformed from one form to another or from one object to another. The sum of energy in the process of transformation and transfer is constant. This is the law of conservation of energy. Class perpetual motion machine can't be made
The transformation and transfer of energy is directional, just as heat can spontaneously transfer from a hot object to a cold object but cannot spontaneously transfer from a cold object to a hot object without causing other changes. It is also the annihilation of the dream of making a perpetual motion that cannot be made.
The term perpetual motion machine is not very appropriate. Such as a flywheel, once the movement begins, if there is no friction resistance, it can continue to exercise for a long time, which is difficult to achieve in practice, but it makes sense in the truth, can be regarded as a practical limit situation. The so-called perpetual motion machine does not refer to this situation. It is not trying to maintain an eternal movement. Instead, it expects to continue to get useful work without external energy supply, that is, without consuming any fuel and power. If this kind of perpetual motion machine can really be made, then you can get unlimited power without any natural energy. When people have not mastered the basic laws of nature, this idea has tempted many people with outstanding creative talents. They have devoted a great deal of wisdom and labor to the realization of this dream. However, no perpetual motion machine has been actually manufactured, and no design of a perpetual motion machine can be subject to scientific review.
An early famous design of a perpetual motion machine was proposed by the Frenchman Hennessel in the 13th century. The device designed by Henneke was not called a perpetual motion machine at the time, but it was called "the magic wheel" according to its particularly attractive nature. He mounted 12 active short rods equidistantly on the edge of a wheel with a heavy ball on each end. Regardless of where the wheel is turned, the individual heavy balls on the right are always farther away from the axis than the heavy balls on the left. Henneke envisions that the larger effect on the right side, especially if the heavy ball in the past acts at a distance from the axis, it will force the wheel to rotate in the direction indicated by the arrow, at least to the axle. When it is worn out. However, in fact, the wheel stopped after one or two turns.
Later, the Leonardo da Vinci (1452-1519) of the Renaissance Italy also made a similar device. He designed that the heavy ball on the right side is farther away from the center of the wheel than the heavy ball on the left side. Under the unbalanced effect on both sides, the wheel will rotate in the direction of the arrow, but the experimental result is negative. Da Vinci is keenly concluded that perpetual motion is impossible.
In fact, from the principle of leverage balance, in the above two designs, although the weight of each weight applied to the wheel on the right side is large, the number of weights is small. Accurate calculations can prove that there will always be a proper position, so that the rotations (torques) in the opposite direction of the weights applied to the wheels on the left and right sides are exactly equal, cancel each other out, and the wheels reach equilibrium and stand still.
The difference in running water can drive the turbine to provide external power. Can we design the perpetual motion machine with running water? In the 1670s, an Italian mechanic, Ster, proposed a design for a perpetual motion machine. He designed that the water flowing from the upper tank would impact the water wheel to rotate, and the water wheel would drive the water mill to rotate, and then drive the spiral decanter through a set of gears to lift the water in the reservoir to the upper tank. in. He thought that the whole device could be kept running like this and effectively doing work externally. In fact, the water flowing back to the sink is getting less and less, and soon the water in the sink flows into the reservoir below, and the turbine stops rotating.
Buoyancy is also a good helper for designing perpetual motion. It is a famous buoyancy perpetual motion design. A series of balls, wound around the upper and lower wheels, can be rotated like a chain. Some of the balls on the right are placed in a container filled with water. The designer believes that if there is no container of water on the right side, the number of balls on the left and right sides is equal, and the chain will be balanced. However, now the balls on the right are immersed in the water, and when they are subjected to the buoyancy of the water, they will be pushed up by the water, which will drive the whole ball around the upper and lower wheels. There is a ball above the water surface. Below, there is a ball that passes through the bottom of the container and is added.
Such a perpetual motion machine has not been made. Is it because the ball below can pass through the bottom of the container without letting the water leak out? Is it technically difficult to manufacture? Technical difficulties are not the main problem, the main problem is still in the design principle. When the lower ball passes through the bottom of the container, it is subjected to the same pressure as the bottom of the container, and because it is at the lowermost part of the water, it is subjected to a large pressure. This downward pressure will offset the buoyancy of the above balls, and the water motive will not move forever.
In addition, various types of perpetual motion design schemes that utilize the inertia of the wheel, the capillary action of the thin tube, and the electromagnetic force to obtain effective power have been proposed, but all fail without exception. In fact, in all perpetual motion design, we can always find a balance position, in which each force just offsets each other and no longer has any driving force to make it move. All perpetual motion machines will inevitably rest in this equilibrium position and become non-motivated.
The endless stream of perpetual motion design schemes failed in the rigorous examination of science and the ruthless test of practice. In 1775, the French Academy of Sciences announced that "the Academy of Sciences will not review all designs of perpetual motion machines in the future." This shows that in the scientific community at the time, it has been recognized from the long-term experience that the attempt to create a perpetual motion machine has no hope of success.
The failure of various perpetual motion design schemes and the bursting of the dream of creating a perpetual motion machine is a big blow to everyone who is looking for perpetual motion. However, reflecting on the failure of this exploratory process, it inspires mankind from the opposite side. Some scientists have begun to think from this negative conclusion and raise the question of whether a perpetual motion machine cannot be made, or whether there is a law in nature. It makes it impossible for us to gain energy out of nothing! That is to say, there is a certain transformation relationship between various energies in nature. Thinking in this area is one of the clues to the establishment of energy transformation and conservation principles. The famous German physicist and physiologist H. Helmholtz (1821-1894) began to study the principle of energy conversion and conservation from the fact that the perpetual motion could not be realized. He wrote in his paper: "In view of the failure of previous experiments, people... no longer ask 'how can I use the known and unknown relationship between various natural forces to create an eternal movement', but ask 'If eternal movement is impossible, what kind of relationship should there be between various natural forces?'"
In the middle of the 19th century, the principles of energy conversion and conservation were widely recognized by the scientific community. This principle points out that all matter in nature has energy, corresponding to different forms of motion, and energy has different forms, such as kinetic energy and potential energy of mechanical motion, internal energy of thermal motion, electromagnetic energy of electromagnetic motion, and chemical motion. Can wait, they are represented by specific state parameters of various sports forms. When the form of motion changes or the amount of movement shifts, energy is also transformed from one form to another, from one system to another; the total energy is constant throughout the transformation and transmission.
There is another very wonderful fantasy that does not violate the principles of energy conversion and conservation. If the heat energy in the air or sea water can be transformed into the mechanical work we need through a clever machine, it can be an inexhaustible source of energy. The idea of inventing such a machine is much more intelligent than the idea of generating energy out of thin air. If this kind of machine can be invented, there is another advantage. On the one hand, we can take out the heat energy in one thing and do it, and at the same time reduce the temperature of such things. In this way, we can set up some huge factories on the ocean, using the heat energy in the sea water to carry out various kinds of work, such as using it to generate electricity. One ship can use the heat in the sea water without burning coal or burning oil. It’s not a good thing to be able to sail around the world! This can be called a second kind of perpetual motion machine, and it is impossible to achieve because it is contrary to the second law of thermodynamics.
The second law of thermodynamics is an objective law that has been proved by countless times of practice. It can be expressed as: "It is impossible to extract heat from a single heat source and turn it into useful work without any other influence." That is to say, the heat engine cannot have 100% efficiency, it has to be taken from high temperature. While part of the heat absorbed by the heat source becomes useful, another part of the heat is placed in the low temperature heat source.
Pursuing the failure experience of perpetual motion can give us two inspirations: First, the experience of failure also has positive scientific research value. The failure of various design schemes of perpetual motion has aroused people's reflection and inspired the idea of energy transformation and conservation. It is one of the clues to establish the principle of energy transformation and conservation; secondly, it must be based on scientific laws. People who pursue perpetual motion in history are not because they do not have a good desire, nor because they lack the spirit of diligent study, but because they are doing work that violates objective laws. Before people can understand the laws of energy transmission and transformation, we can only regret the failure of those seeking for perpetual motion. However, if someone else designs a perpetual motion today, he is stupid. Those who violate the laws of science will never succeed.
No form of perpetual motion machine exists. The principle of permanent magnet power generation is wire cutting magnetic line. The cutting of the magnetic line in the magnetic field is subject to the reaction of the magnetic field, so it is necessary to continue to power the cutting action of the wire. To put it simply, in the generator, it is the process of converting kinetic energy into electrical energy. The only difference is who provides the kinetic energy. For hydropower stations, it is said that gravitational potential energy is converted into kinetic energy; in thermal power plants, the chemical energy of coal is converted into thermal energy, and then transformed into kinetic energy through the phase transformation of water.