The ball on the right is farther away from the axis than the ball on the left, so the ball on the right produces more rotating torque than the ball on the left. In this way, the wheel will rotate endlessly in the direction indicated by the arrow, driving the machine to rotate. This wheel is called "Hennicke's magic wheel", which makes scientists dream of "perpetual motion machine" and scientists have illusions.
Once the perpetual motion machine is born, human beings will produce endless energy. Therefore, many scientists have been trying to recreate the "Hennekov Magic Wheel", but they all failed miserably. However, countless failures have not discouraged scientists, and the exploration of perpetual motion machine has become more and more enthusiastic. Later, leonardo da vinci made a similar device in Renaissance Italy.
When he designed it, he thought that the heavy ball on the right was farther away from the center of the wheel than the heavy ball on the left, and the wheel would rotate endlessly in the direction of the arrow under the action of imbalance on both sides, but the experimental results were negative. Leonardo da Vinci keenly concluded that perpetual motion was impossible. In fact, according to the principle of lever balance, in the above two designs.
Although each weight on the right has a great rotating effect on the wheel, the number of weights is small. Accurate calculation can prove that there will always be a suitable position, so that the opposite rotating action (torque) exerted by the weights on the left and right sides on the wheel is just equal, which cancels each other and makes the wheel balance and come to a standstill.
Nevertheless, scientists have never given up this dream, and people have also put forward various perpetual motion machine designs that use the inertia of wheels, capillary action of thin tubes, electromagnetic force and so on to obtain effective power, but all failed without exception. 1847, German scientist Helmholtz published his book "Conservation of Force".
He proposed that all natural phenomena should be explained by the motion of particles interacting with the central force. At this time, the first law of thermodynamics, that is, the law of conservation of energy, has a vague prototype. 1850, clausius published a paper, which discussed the power of heat and the law of heat itself which can be deduced from it.
He believes that the only principle is that "in all cases where work is generated by heat, heat is consumed in direct proportion to the work generated, and conversely, the same amount of work can be consumed to generate this amount of heat." Add a principle that "any amount of heat is transferred from a cold object to a hot object without any force consumption or other changes, which is contrary to the behavior of thermite" to demonstrate. Think of heat as a state quantity.
Thus, Clausius finally got the analytical formula of the first law of thermodynamics: dQ=dU-dW. Since 1854, Clausius has done a lot of work, trying to find an acceptable proof method to explain this principle. After many efforts, the principle of conservation of energy, that is, the first law of thermodynamics, began to be generally recognized at 1860.
The principle of conservation of energy is expressed as follows: the change of total energy of a system can only be equal to the amount of energy transmitted into or out of the system. Total energy is the sum of mechanical energy, thermal energy and any form of internal energy except thermal energy. The first law of thermodynamics declares perpetual motion machine bankrupt, because perpetual motion machine violates the law of conservation of energy and mass.
We can always find an equilibrium position, where the forces just cancel each other out and there is no longer any driving force to make it move. All perpetual motion machines will inevitably stop at this equilibrium position and become unpowered. The first law of thermodynamics also contributed to the birth of the steam engine and directly led to the birth of the first industrial revolution.
Thus, mankind entered age of steam, and the era of mechanized production began to come. However, the law of conservation of energy has not dispelled the dream of scientists, who dream of building another perpetual motion machine, hoping that it will not violate the first law of thermodynamics and be economical and convenient. For example, this kind of heat engine can directly absorb heat from the ocean or atmosphere and convert it into mechanical work.
Because the energy of the ocean and atmosphere is inexhaustible, this kind of heat engine can work endlessly and is also a perpetual motion machine. To put it simply, people realize that energy can't be generated out of thin air, so they try to absorb heat energy from the ocean, atmosphere and even the universe as the source of power to drive the perpetual motion machine to rotate.
A heat engine that absorbs heat from a single heat source and converts it into useful work without other functions is also called the second kind of perpetual motion machine. Scientists believe that as long as there is only one single heat source, all the heat it absorbs from this single heat source can be used to do work without causing other changes, and the second perpetual motion machine can succeed.
At this time, with the development of science, some limitations of Newton's classical mechanics have also been exposed. For example, Newton's classical mechanics thinks that the mechanical process is reversible, and reversibility refers to the reversal of time, that is, the process is carried out in the opposite order. In the equation of motion of classical mechanics, changing the time parameter t to -t means that the process goes through all the initial states in reverse order and finally returns to the initial state.
1850, Clausius put forward a basic law in his paper: "Without some kind of power consumption or other changes, it is impossible to transfer heat from low temperature to high temperature." This law is called the second law of thermodynamics. The second law of thermodynamics contradicts the reversibility of mechanical processes.
Therefore, in 1854, Clausius put forward a new physical quantity to explain this phenomenon. In 1865, this physical quantity was officially named entropy, which was represented by symbol S. From the point of view of heat engine efficiency, Clausius realized that positive transformation (from work to heat) could be carried out spontaneously.
However, negative transformation (successful thermal transformation), as the reverse process of positive transformation, cannot be carried out spontaneously. The occurrence of negative transformation needs to be accompanied by a positive transformation, and the energy of positive transformation is greater than that of negative transformation, which actually means that the positive transformation of nature cannot be restored. Therefore, Clausius put forward another expression of the second law of thermodynamics, also known as the principle of entropy increase.
That is, the small increment of entropy in irreversible thermodynamic process is always greater than zero. In the natural process, the total degree of chaos (that is, "entropy") of an isolated system will not decrease. In short, the entropy of an isolated system never decreases automatically, remains unchanged in the reversible process and increases in the irreversible process, which can be said to point out the direction of the irreversible process very clearly.
The principle of entropy increase is another expression of the second law of thermodynamics, but it has a deeper meaning. It created the concept of "entropy". This concept was later widely used. Shannon extended the concept of entropy to the process of channel propagation, thus establishing the discipline of "information theory", thus announcing the arrival of the information age.
The principle of entropy increase shows that under adiabatic conditions, only the process of dS≥0 can occur, where dS = 0 represents a reversible process. DS>0 stands for irreversible process, ds
Adiabatic process is a changing process of adiabatic system, that is, there is no heat exchange between the system and the environment. In the adiabatic process, Q = 0, there are δ S (adiabatic) ≥ 0 (greater than irreversible, it is equal to reversible) or dS (adiabatic) ≥ 0 (> 0 is irreversible; The greatest significance of the principle of entropy increase is to specify the direction, conditions and limits in the process of energy conversion from the perspective of energy quality.
The appearance of entropy increase principle shows that the reversibility of classical mechanics is not applicable to all cases, and it is accurate only when it is guaranteed by universal mechanical principles, and thermal motion is an irreversible process. At the same time, it completely declared the demise of permanent power. Because it is impossible to absorb heat from seawater to do work, that is, to absorb heat from a single heat source, making it completely useful without other effects.
Schrodinger pointed out that the process of entropy increase must also be reflected in the life system. In other words, the entropy in the life system should also be increasing, and it can only develop from order to disorder. But from a certain point of view, the meaning of life lies in the ability to resist the increase of self-entropy, that is, the ability to reduce self-entropy, and the most typical performance is eating behavior.
We draw "negative entropy" from food to maintain the order of life, that is, "the essence of metabolism is to eliminate the negative entropy produced by all organisms all the time." Order and disorder here describe the macro state. So the body successfully absorbs negative entropy from the surrounding environment in the process of metabolism.
Release all the positive entropy necessary for its life activities to the surrounding environment to maintain its survival and evolution. In a word, life is an open and irreversible non-thermodynamic equilibrium system. The equilibrium state is disordered, while the non-equilibrium state is the root of order, which accords with the second law of thermodynamics and the principle of entropy increase. Schrodinger vividly summed it up with the famous saying "Life depends on negative entropy".
Even so, the entropy reduction behavior of life has no effect. After all, in the vast universe, human beings and other life are simply insignificant. The inevitability and irreversibility of entropy increase doomed that life can only develop from order to disorder, and finally to aging and death. So the principle of entropy increase is also called by many people: the most desperate physical law.
The principle of entropy increase is applicable to many fields, including whether it contradicts Darwin's theory of evolution. The biggest debate among scientists on the principle of entropy increase is whether the universe is a closed system, because the condition of entropy increase must be in an isolated system, and then the equilibrium entropy is maximized. Isolated system in thermodynamics.
A system that has neither material exchange nor energy exchange with other objects is called an isolated system. No energy or mass can enter or leave an isolated system, but can only move within the system. The earth is an open system, and the principle of entropy increase can be applied to life and naturally to the earth.
Therefore, the living things on the earth keep themselves in a low-entropy ordered state by absorbing low-entropy substances (ordered polymers) from the environment and releasing high-entropy substances (disordered small molecules) to the environment. The negative entropy flow of the whole earth comes from plants absorbing the light flow of the sun (negative entropy flow) and producing low entropy substances. This orderly life structure will appear on the earth.
It won't keep entropy increasing, so scientists wonder whether the universe is an isolated system, because there is no "outside" in the universe, and we are constantly consuming energy, which is irreversible. Entropy is increasing and moving to the maximum, so once the universe reaches thermodynamic equilibrium, it will die out completely.
This scene is called "thermal silence", and there is no energy in this universe that can sustain movement or life. This has attracted opposition from some scientists, who claim that the principle of entropy increase can only be applied to systems composed of a large number of molecules and macro-processes in a limited range. It is not suitable for a few microscopic systems, nor can it be extended to the infinite universe.
Because it involves the future of the universe, the fate of mankind and other major issues, its influence has gone far beyond the scientific and philosophical circles, becoming the most annoying mystery in modern history. As one of the four laws of thermodynamics, the principle of entropy increase guides the study of thermodynamics and plays an important role in physics.