Franklin's most famous discovery was the unification of sky and earth electricity, which broke people's superstition about lightning. In the process of discharge experiment with Leiden bottle, Franklin could not help but think of lightning in the sky in the face of the flash and crack of electric spark. He realized that the spark in the Leiden bottle might be a small lightning. In order to test this idea, lightning in the sky must be brought to the ground. On a thunderstorm day in July, Franklin made a big kite out of silk. At the top of the kite, a thin iron wire is installed, which is connected to the ground with silk thread. At the end of the silk thread is tied a copper key, which is inserted in a Leyden bottle. Franklin put the kite in the sky, and a flash of lightning struck, only to see the hairs on the silk thread stand up and put his hand close to the copper key, which is an electric spark. The Temple of Heaven was finally caught. Franklin discovered all the phenomena that the Leiden bottle that stored the sky electricity could produce the earth electricity, which proved that the sky electricity and the earth electricity were the same. 1747, Franklin discovered the phenomenon that the tip is easier to discharge from the Leyden bottle experiment. After he discovered the unification of sky electricity and ground electricity, he immediately thought of using the principle of tip discharge to introduce powerful lightning in the sky into the ground to avoid buildings being struck by lightning. 1760, Franklin erected a lightning rod on a building in Philadelphia, and the effect was very remarkable.
Newton was killed by an apple and discovered the law of gravity.
Russian chemist Mendeleev (1834~ 1907) was born in Siberia. He loved labor, nature and hard work since he was a child.
1860, Mendeleev was deeply troubled by the lack of systematicness in inorganic chemistry when considering the writing plan of the book Principles of Chemistry. Therefore, he began to collect information about the nature of various known elements and related data, and collected all the achievements made by predecessors in practice. The long-term practice and cognitive activities of human beings on the issue of elements have provided him with rich materials. On the basis of studying predecessors' achievements, he found that some elements have * * * in addition to their characteristics. For example, fluorine, chlorine, bromine and iodine of halogen elements are known to have similar properties; Alkali metal elements such as lithium, sodium and potassium are oxidized quickly in the air, so they can only exist in the form of compounds in nature. Some metals, such as copper, silver and gold, can be kept in the air for a long time without corrosion, which is why they are called precious metals.
So Mendeleev began to try to arrange these elements. He made a rectangular cardboard for each element. Element symbols, atomic weights, element properties and their compounds are written on each rectangular cardboard. Then nail them to the wall of the laboratory and arrange them repeatedly. After a series of queues, he discovered the regularity of chemical properties of elements.
Therefore, when someone regarded Mendeleev's discovery of the periodic law of elements as simple and easily said that he got this great discovery by playing poker, Mendeleev seriously replied that it took him about 20 years to publish the periodic law of elements in 1869. He picked out the chemical elements from the chaotic maze. In addition, because of his great courage and confidence, he was not afraid of famous critics, laughed at, practiced and publicized his own views, and finally he was widely recognized.
periodic law of elements
The periodic law of elements reveals a very important and interesting law: the properties of elements change periodically with the increase of atomic weight, but they are not simply repeated. According to this truth, Mendeleev not only corrected some wrong atomic weights, but also predicted the existence of more than 15 unknown elements. As a result, Mendeleev discovered three elements when he was still alive. 1875, French chemist Bois Baudrin discovered the first filled element, named gallium. All the properties of this element are the same as Mendeleev predicted, but the proportion is inconsistent. Mendeleev wrote a letter to the Paris Academy of Sciences, pointing out that the proportion of gallium should be around 5.9, not 4.7. At that time, the gallium was still in the hands of Boyce Baldwin, and Mendeleev had never seen it. This incident surprised Boise Baudrin, so he tried to purify and re-measure the proportion of gallium, and the result confirmed Mendeleev's prediction that the proportion was indeed 5.94. This result greatly improves people's understanding of the periodic law of elements, and also shows that many scientific theories are called truth, not when scientists create these theories, but when they are constantly confirmed by practice. When Mendeleev predicted new elements through the periodic table, some scientists said that he arrogantly invented some nonexistent elements. Through practice, Mendeleev's theory has been paid more and more attention.
Later, according to the theory of periodic law, people sorted out and classified more than 100 elements that had been discovered, and listed today's periodic table of chemical elements, which was posted on the laboratory wall and arranged at the back of the dictionary. It is a lesson that every student must learn and master when studying chemistry.
Now we know that in the vast universe of human life, all substances are composed of this 100 element, including ourselves.
However, what are chemical elements? Chemical elements are the general name of the same kind of atoms. So people often say that atoms are the "basic bricks" that make up the material world, which is still possible in a certain sense. But the periodic law of chemical elements shows that chemical elements do not exist in isolation and are not related to each other. These facts mean that elements and atoms must have their own internal laws. There has been a revolution in the theory of material structure.
At last, at the end of 19, there was a new development in practice and radioactive elements and electrons were discovered, which was originally an excellent opportunity to uncover the inside story of atoms. However, Mendeleev was puzzled in practice. On the one hand, he is afraid that these findings "will complicate things" and shake "the foundation of the whole world outlook"; On the other hand, I think this "will be a very interesting thing ... the reason for the periodic law may be revealed". But Mendeleev himself died in 1907 with this contradictory thought on the eve of uncovering the essence of periodic law.
Mendeleev didn't see it. It is precisely because of a series of great discoveries and practices at the end of 19 and the beginning of the 20th century that the essence of the periodic law of elements was revealed and the old idea that atoms were inseparable in Mendeleev's era was abandoned. While sublating its inaccurate part, it fully affirms its reasonable connotation and historical position. On this basis, the new theory of periodic law of elements is more practical than Mendeleev's theory.
Mendeleev's life
190765438+1October 27th, the cold wind in Petersburg, the capital of Russia, was bleak, the mercury column on the thermometer dropped to more than 20 degrees below zero, and lanterns covered with black gauze were lit everywhere in the street, showing a sad atmosphere. Tens of thousands of people marched slowly in the street. Walking at the front of the line is neither a wreath nor a portrait, but a big wooden sign held by more than a dozen young students, with many squares written on it, such as "C", "O", "Fe" and "Zn".
It turned out that the deceased was a famous Russian chemist Mendeleev, and the table with many squares on it was the periodic table of chemical elements-Mendeleev's main contribution to chemistry.
Mendeleev was born in a family of middle school principals with 17 children, and he ranked 14. Just a few months after his birth, his father suddenly went blind, and then he lost his position as principal. It is difficult to make a living on a small pension, so the whole family moved to a nearby village because my uncle runs a small glass factory there. The scene of workers melting and processing glass has a great influence on his future chemical research on beakers and flasks. 184 1 In the autumn of, Mendeleev, who was under seven years old, was admitted to the city middle school with his teenage brother, which caused a sensation in the local area. Misfortune is always accompanied by poor families. Mendeleev's father died at the age of 13, and the factory was burned to ashes at the age of 14. The mother had to move again, marry off her adult daughters and let her two sons work. /kloc-in the spring of 0/849, Mendeleev graduated from middle school, and the mother sold her property and was bent on letting her youngest son go to college. With the help of a friend of his father, Mendeleev entered the Physics Department of Petersburg Teachers College. After only one year, he became a top student. In addition to intense study, I also wrote a brief scientific review to get a small amount of manuscript fees. By this time, he had lost any financial support: his uncle and mother died one after another. 1854 graduated from university and won the college gold medal. He became an associate professor at the age of 23 and a professor at the age of 3 1.
It was "organic chemistry" that made him gain his initial fame. In order to write this book, he never left his desk for almost two months. After the age of 70, I broke down from overwork and my eyes were half blind. Work from early morning to 5: 30 pm every day, and continue to work late into the night after lunch. He died at his desk with a pen in his hand. 1869 The discovery of the periodic law of elements made him famous, and many foreign academies hired him as an honorary academician. Once, a reporter asked him how he came up with the periodic law. Mendeleev said with a smile, "I've been thinking about this question for 20 years. Do you think I'm just waiting for death, and suddenly I succeed?"
It is true that we should always remember Mendeleev's motto: "What is a genius? If you work hard for your life, you will become a genius! "
Edison (1847- 193 1)
19th century is called the century of science, and it is also a century characterized by the technicalization and socialization of science. In this century, science has become an important part of social life. The surging great innovation has become a great driving force for technical science. Some technology giants in this century continued to be active in the 20th century. Thomas Alva Edison is one of them. Among the 65,438+000 most influential people in the past 65,438+0,000 years recently selected by American Life Weekly, Edison ranked first.
Edison came from humble origins and lived in poverty. His life's "education" is only three months of primary school. Because his teacher was always tongue-tied by his strange questions, he even told his mother that he was a fool and would have no future. Mother let him drop out of school in a fit of pique, and she personally educated him. At this time, Edison's talent was fully displayed. Under the guidance of his mother, he read a lot of books and built a small laboratory at home. In order to raise the necessary expenses of the laboratory, he had to go out as a newsboy and run a newspaper. Finally, a small laboratory was built in the luggage compartment of the train with the accumulated money to continue the chemical experimental research. Later, the chemicals caught fire and almost burned the carriage. The furious porter threw all Edison's experimental equipment out of the car and slapped him several times. It is said that Edison was deaf for life.
Edison is a legend admired by the American nation-although he did not receive a good school education, he achieved great success through personal struggle and extraordinary wisdom. Self-taught, he stood up from thousands of failures with perseverance, rare enthusiasm and energy, overcame countless difficulties and became an American inventor and entrepreneur. In his early years, he developed duplex and quadruple telegraph systems and invented the automatic telegraph. 1877 ~ 1879 invented the phonograph; Experiment and improve electric lights (incandescent lamps) and telephones. Later, a lighting system was established and a lot of work was done to realize centralized power supply. He proposed and adopted the DC three-wire system. The generator with the largest capacity at that time was made, and the first large-scale power plant was built with this generator in 1882. At the same time, the railway electrification test was carried out. 1883 discovered "Edison effect", that is, thermionic emission phenomenon. There are also many famous inventions in film technology, mining, architecture and chemical industry. Only from 1869 to 190 1 year, we obtained 1328 invention patents. In his life, there was a new invention every 15 days on average, so he was called "the king of inventions".
Edison devoted himself to science and ignored fame and fortune. When developing electric light, the reporter said to him, "If you can really make electric light instead of gas light, you will definitely make a lot of money." Edison replied: "If a person works only to save money, it is difficult for him to get anything else-even money!" " "He has always been called the father of modern movies, but at the grand banquet held by people in the film industry for his 77th birthday, he said," I just made some technical contributions to the development of movies, and the rest were contributed by others. "
Edison was broad-minded and good at facing adversity. Pointing to the inconvenience caused by his deafness, he said, "Walking in the crowd on Broadway, I can be as calm as a person living in the depths of the forest." Deafness has always been my blessing, saving me a lot of interference and mental pain. "19 14 one night, Edison's film lab suddenly caught fire, which caused great losses. Edison comforted his heartbroken wife and said, "Never mind, although I am 67 years old, I am not old.
From tomorrow morning, everything will start all over again. I believe that no one will be too old to start working. "The next day, Edison not only began to build a new workshop, but also began to invent a new lamp-a portable searchlight to help firefighters move forward in the dark. The fire was like an episode for Edison.
Edison benefited the public and was not afraid of hardship. In order to find the filament, he tested thousands of materials; He failed to try the new battery 8000 times. So Edison often said, "Genius is one percent inspiration and ninety-nine percent diligence." At the age of 80, he still maintained the spirit of an inventor and persevered in his invention and creation activities. 1927, he founded Edison plant research company, devoted himself to a brand-new research field and looked for new chemical materials. Edison, 8 1 year-old, successfully extracted rubber from weeds and was highly praised by people.
1931018 At 3: 24 in the morning, Edison closed his eyes with a relieved smile at the age of 84. On his deathbed, he said frankly: "I did my best for the happiness of mankind;" There is nothing to regret. "
On the day of the funeral, the lights in the United States were turned off for one minute to show their condolences. This is the most solemn way for people to express their infinite memory of Edison, and it is also a silent hymn dedicated to this great inventor.
Albert Einstein was born in Germany on 1879. He has made outstanding achievements in scientific research all his life, the most outstanding of which is that he proved the existence of atoms by experiments, founded the theory of relativity and developed the quantum hypothesis put forward by Planck. Einstein, a famous German physicist, made outstanding contributions to the development of modern physics all his life. His most outstanding achievement is to break through the framework of Newton's classical physics and create the theory of relativity suitable for the field of microscopic high-speed motion.
Before Einstein, since ancient times, people thought that although matter existed in time and space and their movement was restricted by time and space, time and space were not affected by the distribution and movement of matter. In this way, time, space, matter and movement are completely separated and isolated. Newton, a gifted physicist, also believed this view and put forward the concepts of absolute time, absolute space and absolute motion. Einstein disagreed with Newton's view of absolute time and space and absolute motion. Starting from the limited speed of light, he proposed that the time simultaneity of the universe is relative to a certain reference system, for example, the time of events on the moon is relative to the earth reference system. Based on the relativity of simultaneity, he denied Newton's concepts of absolute time, absolute space and absolute motion. Because the simultaneity of time is relative to a certain frame of reference, it is relative; And movement is closely related to time, so movement is also relative. Looking at the earth in isolation, its movement does not exist; Space and time are closely linked, so absolute space does not exist. Thus, Einstein linked seemingly unrelated time and space, making them a closely linked unity of opposites, and founded the special theory of relativity in 1905.
19 16 years, Einstein further completed the establishment of general relativity after 10 years of exploration. General relativity is a new theory of gravity without gravity and a physical law applicable to all reference systems. It is different from special relativity, which only applies to physical processes without gravity. The reference frame of relative motion of a straight line with uniform speed is studied. General relativity studies the frame of reference of any motion, which is not only applicable to the frame of reference of straight line and uniform motion, but also to the frame of reference of accelerated motion and rotary motion, so it is the second floor of the building of relativity. General relativity further shows that time and space are not isolated, and the distribution and motion of matter in turn determine the structure of time and space. They also influence each other and are the unity of opposites. Einstein's theory of relativity is the most important achievement of modern science and technology in the magical century, which led to a complete revolution in ancient physics, completed the third theoretical synthesis of physics, and further laid the cornerstone for the development of modern physics.