What Are the Laws of Energy?

The law of energy conservation, the first law of thermodynamics, means that the total energy in a closed (isolated) system remains the same. Generally speaking, the total energy is no longer just the sum of kinetic energy and potential energy, but the total of static energy (inherent energy), kinetic energy, and potential energy ^[1] .

Energy is a measure of the movement of matter, referred to as "energy." Everything in the world is constantly moving.

Common expression: Energy is neither generated nor disappeared out of thin air, it can only be transferred from one object to another, or transformed from one form to another. In the process of transformation or transfer, energy is always The amount remains the same. ^[4]

The idea of the first law of thermodynamics was originally proposed by the German physicist J. Meyer in 1842 on the basis of experiments.

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Energy cannot be created or destroyed. Energy conservation is one of the universal laws of the movement of matter.

Vitality vs. Death

In 1644, R. Descartes cited the collision problem in Principles of Philosophy.

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The concept of momentum is used to measure motion. In 1687, Newton measured the change in momentum in "Mathematical Principles of Natural Philosophy". What is different is that G. Leibniz attacked Descartes in a 1686 paper, advocating the measure of mass by the square of velocity, which Leibniz called vitality. Newton's force measured by momentum is called dead force. Leibniz's claim is consistent with Huygens conclusions on collision research, which states that when two objects collide with each other, the sum of the product of their mass and the square of the velocity remains unchanged before and after the collision.

Since Leibniz provoked controversy, there has been an argument between the two major factions, Descartes and Leibniz. This controversy lasted for nearly half a century, and many scholars participated in the controversy, each with experimental evidence. In 1743, French scholar J. D'Alembert said in On Dynamics: "For measuring a force, use it to give the vitality of an object affected by it through a certain distance, or use it to give it a certain effect The momentum of an object of time is also reasonable. "D'Alembert revealed that vitality is a measure of force acting on distance, and momentum is a measure of force acting on time. The debate finally settled. Vitality is universally accepted as a formal mechanical term.

Although the concept of vitality is accepted, the relationship between vitality and force has not been clarified. In 1807, the British scholar T. Young introduced the concept of energy, and in 1831 the French scholar G. Coriolis introduced the concept of force and work, indicating that the work of force is transformed into the kinetic energy of objects, that is, the conservation of mechanical energy in nature.

Mayr's discovery

J. Meyer (1814-1878) was a German physicist.

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On the voyage to Java in 1840, he became interested in physics because of the temperature of animals. When he treated the sick sailor for bloodletting (a popular therapy at the time), he found that the veins were brighter. He thought that the bright red blood was in the tropics, and the body did not need more oxygen to burn to maintain body temperature than in the temperate zone. This phenomenon prompted Meyer to think about the fact that food in the body was converted into calories and the body was able to do work. It is concluded that heat and work can be converted into each other.

He noticed that many people's experiments on perpetual motion at the time ended in failure, leading him to speculate that "mechanical work cannot be produced at all".

In his letter to his friends on September 12, 1841, the earliest mention of thermal equivalent: "It is still very important to solve the following problem: how high must a heavy object (such as 100 pounds) be lifted on the ground to The amount of exercise corresponding to this height and the amount of exercise obtained by dropping the weight is exactly equal to converting one pound of 0 ° C ice into 0 ° C water

Mayr

The necessary heat. "

In 1840, Mayr began to think about where the heat comes from. The movement of the heart cannot generate so much heat and cannot maintain a person's body temperature. Body temperature is maintained by the whole body's flesh and blood. This comes from food and eventually comes from plants. Plants grow by absorbing the light and heat of the sun. In the end it comes down to how energy is transformed (transferred)?

Mayer wrote an article "On the Power of the Inorganic World" and measured the thermal work equivalent to 365 kgm / kcal. I submitted my thesis to the Physics Yearbook, but it was not published. Not only is it not understood academically, it has also experienced major blows in life. In 1858, the world rediscovered Meyer and was awarded an honorary doctorate by the Swiss Academy of Natural Sciences in Basel. Copley Medal of the Royal Society, Honorary Doctor of Philosophy from the University of Tübingen, Academician of the Academy of Sciences of Bavaria and Turin.

Meyer was the earliest scholar to perform thermal equivalent experiments, although his experiments were rougher than those of Joules. He first described the law of conservation of energy: "The proof of the absolute truth of my law is the opposite proof: a universally accepted theorem scientifically: the design of perpetual motion is absolutely theoretically impossible.

Meyer demonstrated that the sun is the ultimate source of all living and non-living energy on Earth.

Later, Helmholtz and Joule's papers were published one after another. People attributed the inventor of the law of conservation of energy to Helmholtz and Joule, and did not acknowledge Mayr.

Helmholtz read Meyer's 1852 paper in 1858, acknowledging that Mayer's ideas predate his widely influential thesis. Clausius also believed that Mayr was the discoverer of the law of conservation. In 1862 Tyndall systematically introduced Meyer's work at the Royal Society of London, and his achievements were finally recognized by society.

The discovery of Helmholtz

On July 23, 1847, H. Helmholtz (1821-1894) made a report to the Physics Association entitled "Conservation of Power" and handed the article to the editor of the Chronicle of Physics. In 1841, Mayr's manuscript suffered the same fate, and the editor refused to publish it without experimental facts. He published his thesis as a pamphlet in a well-known publishing house. The conclusion of the article is completely consistent with the Joule experiment in 1843, and it was soon called "the highest and most important principle in nature." Due to the publication of well-known publishers, Helmholtz's and Maier's fate was completely different. British scholar Kelvin adopted the concept of energy proposed by T. Young, adopted "potential energy" instead of "elastic force" and "kinetic energy" instead of "vitality". The ambiguity of the concept that has continued in mechanics for nearly 200 years has changed.

The law of conservation of energy is a basic law universal in nature and a powerful weapon for people to understand and use nature.