As shown in the figure: there is a rotating shaft in the center of the wheel, and 12 movable short rods are installed at the edge of the wheel, and one end of each short rod is equipped with an iron ball. Subsequently, people who studied and invented perpetual motion machines constantly emerged. Although many scholars have pointed out that perpetual motion machine is impossible, people who study perpetual motion machine are still moving forward wave after wave. Leonardo da Vinci (1452- 15 19), a great Italian scholar in the Renaissance, once studied perpetual motion. What is commendable is that he finally came to the conclusion that perpetual motion machine is impossible. At the same time as Leonardo da Vinci, there was an Italian named Cardin (Jerome Cardin,1501-kloc-0/576). He was first famous for giving the roots for solving cubic equations, and he also thought perpetual motion machine was impossible. Regarding the impossibility of perpetual motion machine, we should also mention the Dutch physicist simon stevin (1548 1620). /kloc-before the 6th century, in statics, people only dealt with the problem of finding the resultant force of parallel force systems and its balance, and the problem of decomposing a force into parallel force systems, but not the balance of intersecting force systems. In order to solve this problem, people boil it down to solving the balance problem of three intersecting forces. The problem was solved by clever debate. Suppose you put a uniform chain ABC on an asymmetric upright (frictionless) wedge, as shown in the figure. At this time, the chain is affected by the reaction force on the two contact surfaces and its own gravity. It happens to be three converging forces. Will the chain slide here or there? If so, which way? Stephen imagined stopping the wedge in the air and connecting the chain at the bottom with CDA, as shown in the figure, and finally solved the problem. The chain hanging at the bottom is self-balancing. Connect the suspension parts with the upper chain. Stephen said, "If you think the chain on the wedge is unbalanced, I can be a perpetual motion machine." In fact, if the chain will slide, then you will inevitably introduce that the closed chain will slide forever; This is obviously absurd, and the answer must be that the chain does not move. He got three conditions of balance of power. He thought this proof was wonderful, so he put Figure 2 on the title page of his book The Essence of Mathematics, and his colleagues carved it on their tombstones to show their admiration. The solution of the balance problem of cross force system also marks the maturity of statics. With the impossibility of perpetual motion machine, some countries have imposed restrictions on perpetual motion machine. For example, as early as 1775, the French Academy of Sciences decided not to publish a newsletter about perpetual motion machines. 19 17, the us patent office decided not to accept the patent application of perpetual motion machine. According to F. Charlesworth, assistant evaluator of British Patent Office, the first patent of perpetual motion machine in Britain was 1635. Between 16 17 and 1903, the British Patent Office received about 600 patent applications for perpetual motion machines. This does not include the patent application for perpetual motion machine using the principle of gravity. However, in the United States, after 19 17, there are still many perpetual motion machine schemes that can't see the mystery at the moment and are accepted by the patent office. Julius Robert Meyer (18 14- 1878) is a German physicist. He studied medicine in university, but he didn't like being a doctor. He is a ship doctor, and his work is relatively leisure.
In the west, there has been a large-scale bloodletting therapy since about the 4th century. About 12 to 13 ounces (about 340-370 grams, as much as a cup) of blood will be discharged at a time, and the rest will be discharged until the patient feels dizzy. The basis of this therapy is a so-called "liquid pathology" theory in the ancient west, which holds that the human body contains many kinds of liquids, such as blood, phlegm and bile. Too much or not enough of these liquids will cause diseases. The function of bloodletting is to remove excess fluid. In the Middle Ages, the rich in the West, especially those noble elites and gentlemen, had to bleed regularly all year round, usually once in spring and autumn. Another function of bloodletting is to make women look better, which is related to the western aesthetic standards at that time, making them look white and not ashamed. So western ladies often bleed. As a doctor, it goes without saying that Meyer often uses bloodletting therapy to treat people. About 1840, during the voyage to Java, I became interested in physics because of the consideration of animal body temperature. In Surabaya, when he bled some sick sailors, he found that the blood in the veins was bright. At first, he mistakenly thought that he had cut the wrong artery. So, he thought, blood is redder in the tropics, and the body doesn't need to burn more oxygen to keep its body temperature as it does in temperate regions. This phenomenon prompted Meyer to think about the fact that food in the body is converted into heat and the body can do work. It is concluded that heat and work can be transformed into each other. He also noticed that many people's experiments with perpetual motion machines ended in failure at that time, which left a profound influence on him since he was a child. These made him guess that "mechanical work can't be created from scratch."
The mechanical equivalent of heat was first mentioned in his letter to a friend on September 184 1. He said: "For my theory that can be explained by mathematical reliability, it is still extremely important to solve the following problem: How high must a heavy object (for example, 100 pounds) be lifted to the ground, so that the amount of exercise corresponding to this height and the amount of exercise obtained by putting down the heavy object are exactly equal to the heat required to convert a pound of ice at 0℃ into water at 0℃." 1840 On February 22nd, he came to India with a fleet and worked as a doctor on board. One day, the fleet landed in Calcutta, and the crew got sick because of acclimatization, so Mayer bled the crew according to the old method. In Germany, you only need to insert a needle into the patient's vein to treat this disease, and you can release a stream of dark red blood, but here, it is still bright red blood flowing out of the vein. Therefore, Meyer began to think: human blood is red because it contains oxygen, which burns in the human body to generate heat and maintain the body temperature. It's very hot here, and people don't need to burn so much oxygen to maintain their body temperature, so the blood in the blood vessels is still bright red. So, where does the heat come from? A heart with a maximum of 500 grams can't generate so much heat by its movement, and it can't maintain a person's body temperature alone. That body temperature is maintained by the whole body's flesh and blood, which comes from the food people eat. Whether they eat meat or vegetables, they must come from plants, and plants grow by the light and heat of the sun. What about the heat of the sun? If the sun is a piece of coal, it can burn for 4600 years, which is of course impossible. It must be something else, energy we don't know. He boldly introduced that the center of the sun is about 20 million degrees (now we know it is150,000 degrees). The more Meyer thinks about it, the more it boils down to one point: how is energy transformed (transferred)? On his return to Hamburg, he wrote an article "On the Force of Inorganic Boundary" and measured the thermal mechanical equivalent of 365 kg m/kcal by his own method. He submitted a paper to the Yearbook of Physics, but it was not published, so he had to publish it in a little-known medical journal. He gave speeches everywhere: "Look, the sun gives off light and heat, and plants on the earth absorb them and produce chemicals ..." But even physicists couldn't believe his words and called him "crazy" disrespectfully. Meyer's family also suspected that he was crazy and asked a doctor to treat him. Not only was he not understood academically, but he also experienced a blow in his life. His youngest son died and his younger brother was involved in the revolutionary activities. In a series of blows, Meyer committed suicide by jumping off a building at 1849, but he failed, but his legs were disabled and he became a cripple. Then he was sent to Gogentin mental hospital and suffered inhuman torture for eight years. 1858, the world rediscovered Meyer. After he came out of the mental hospital, he was awarded an honorary doctor by the Basel Academy of Natural Sciences. Meyer in his later years can be said to have suffered a lot. In his later years, he was awarded the copley Medal of the Royal Society, an honorary doctor of philosophy from the University of Tiebingen, and an academician of the Bavarian and Italian Academy of Sciences. 1On March 20th, 878, Meyer passed away in Haier. 1842 In March, Meyer wrote a short article "Views on Force in Inorganic Field" and sent it to Justus von Liebig, editor-in-chief of Chronicle of Pharmacy and Chemistry (Justus von Liebig, 1803- 1873). Justus von Liebig immediately agreed to use this article. This paper explains the mechanical equivalence of heat for the first time. It is found that the work done by a heavy object falling from a height of about 365 meters is equivalent to the heat required to raise the same weight of water from 0℃ to 1℃. His article was published in May 1842. Meyer was the first scholar to carry out mechanical equivalent thermal experiments. 1842, he used a horse-drawn mechanical device to stir the pulp in the pot, compared the work done by the horse with the temperature rise of the pulp, and gave the mechanical equivalent of the calorific value. His experiment was rougher than Joule's later experiments, but he deeply realized the great significance of this problem and expressed the law of conservation of energy for the first time. In his letter to a friend at the end of 1842, he said: "I think subjectively, it is this opposite proof that shows the absolute truth of my law: that is, a universally recognized theorem in science: the design of perpetual motion machine is absolutely impossible in theory (that is, even if people do not consider mechanical difficulties, such as friction, etc., it is impossible for people to design it successfully ideologically). And all my assertions can be regarded as pure conclusions drawn from this impossible principle. If someone denies my theorem, then I can build a perpetual motion machine at once. " Meyer's paper did not attract social attention. In order to make up for the shortcomings of the first paper, he wrote a second paper, which was not adopted. He proved that the sun is the ultimate source of all living and abiotic energy on earth. Later, Helmholtz and Joule's papers were published one after another, and people attributed the inventor of the energy conservation theorem to Helmholtz and Joule. However, although his paper was early and systematic, it was not only not recognized, but also attracted some attack articles. Add 1848, it never rains but it pours. Two children died and his younger brother was involved in revolutionary activities. 1849, Meyer jumped from the third floor and became severely disabled. Later, he was diagnosed with schizophrenia and sent to a mental hospital. Doctors think that the new discovery he often talks about is the mental symptom of megalomania. 1858 Helmholtz read Meyer's 1852 paper and admitted that Meyer was earlier than his influential paper. Clausius also thinks that Meyer is the discoverer of conservation law. Clausius told this fact to the British vocalist john tyndall (1820- 1893). It was not until 1862 that Tindal systematically introduced his work at the Royal Society of London, and his achievements were recognized by the Society. 1860, Meyer's early papers were translated into English and published. 1870, Meyer was elected as a member of the Communication Academy of Paris Academy of Sciences and won the Pang Si Prize. After that, Meyer's fate improved greatly. With regard to the latest research on the law of conservation of energy, some researchers believe that the law of conservation of energy needs conditional restrictions, and it is not universal in any situation and any time and space, and the invariance of time translation is the condition of conservation of energy. Through the analysis of the law of conservation of energy, some researchers believe that the basic condition for the establishment of the law of conservation of energy is that the conversion of various forms of energy follows the principle of equivalent conversion, and point out that it is a lack of understanding of the law of conservation of energy to equate the ∑ E= constant with the law of conservation of energy in physics for a long time. People's understanding and research on the law of conservation of energy need to be further deepened.