Michael faraday (1791-1867) is the greatest experimental physicist in the field of electromagnetism in the 9th century. He was born on September 22nd, 179 1, Newton near London. His father is a blacksmith. Because of his poor family, he only attended primary school for two years from the age of seven to nine. /kloc-became a newsboy at the age of 0/2, and/kloc-became an apprentice in a bookstore at the age of 0/3. He likes reading books, taking advantage of the conditions in the bookstore, reading a lot of scientific books and doing some simple chemical experiments.

18 12 In the autumn, Faraday had the opportunity to listen to four speeches by the famous chemist David, which aroused his great interest in scientific research. He carefully arranged David's speech and sent it to David with illustrations, hoping that David would help him realize his scientific research wish. 1865438+In March 2003, David recommended Faraday as his assistant experimenter in the laboratory of the Royal Institute. 18 13 10, Faraday followed David to the European continent 18 months. During this period, he had the opportunity to visit the laboratories of scientists from various countries, make friends with famous scientists such as Ampere and Gay-Lussac, and learn about their scientific research methods. After returning to England, Faraday began his independent research work, and published his first chemical paper in 18 16, and later published several articles in succession.

1820, Oster discovered the magnetic effect of current, which attracted the attention of the scientific community and promoted the development of science. 182 1 year, the editor-in-chief of British Philosophical Yearbook invited David to write an article to comment on the theoretical development of electromagnetic experiments since Oster's discovery. David gave Faraday the job. In the process of collecting data, Faraday became very enthusiastic about the study of electromagnetic phenomena and began to turn to the study of electromagnetism. He carefully analyzed the magnetic effect of current and other phenomena, and thought that since current can produce magnetism, can magnetism produce electricity? 1822, he wrote down his idea in his diary: "Magnetic energy is converted into electricity". He made a systematic study in this field. At first, he tried to approach a closed conductor with a strong magnet, or to generate a current in another closed conductor with a strong current. He did many experiments and failed. Ten years of failure, re-examination, until August 29th 183 1 success. He has done dozens of such experiments in succession. In the paper 183 1 year165438+1October 24th, he classified the induced current into five categories: variable current; A changing magnetic field; Constant current of motion; Moving magnetic field; A conductor moving in a magnetic field. He pointed out that the induced current is related to the change of the original current, but not to the original current itself. He compared this phenomenon with electrostatic induction on a conductor and named it "electromagnetic induction". In order to explain the electromagnetic induction phenomenon, Faraday once put forward the concept of "electric tension". Later, after considering various situations of electromagnetic induction, it is considered that the induced current can be attributed to the "cutting magnetic field lines" of the conductor. Twenty years after the discovery of electromagnetic induction, it was not until 185 1 that the law of electromagnetic induction was obtained.

From 1833 to 1834, Faraday got the law of electrolysis from experiments, which is the earliest strong evidence of charge discontinuity.

Another contribution of Faraday is to put forward the concept of field. He opposed the viewpoint of distance, and assumed that there was a substance in the space around charged bodies and magnets, which played the role of conducting electricity and magnetism. He called this substance an electric field and a magnetic field. In 1852, he introduced the concepts of electric field line and magnetic field line, and showed the shape of magnetic field line around the magnetic bar with iron powder. The concept of field and the model of force line are a great breakthrough to the traditional concept at that time.

Faraday also foresaw the fluctuation and non-instantaneous propagation of electric and magnetic effects from the physical picture of close interaction. In a sealed letter he wrote to the Royal Society on March 2, 1832, the envelope read "Some new ideas that should be collected in the archives of the Royal Society now". This letter was not unsealed until 1938, in which Faraday explained his new idea. It shows Faraday's profound physical insight and profound physical thought.

Faraday compiled his experiments into a book, Experimental Research on Electricity, which collected more than 3,000 articles and described his experiments and conclusions in detail. This is a precious scientific document.

Faraday is a self-taught scientist, who has worked hard on the scientific journey for more than half a century without seeking fame and fortune. 1825, he participated in the work of smelting stainless steel and double crown glass with good refractive performance, and many companies and manufacturers paid a lot of money to hire Faraday as their technical consultant. Facing the wealth of 6.5438+0.5 million pounds and free study, Faraday chose the latter. 185 1 year, Faraday was unanimously elected as the president of the royal society, and he resolutely declined this position. I devoted myself to scientific research and lived a poor life.

He retired from the Royal College on 1855. 1867 died in London on August 25th. According to his wish to be an ordinary michael faraday all his life, his body was buried in Highgate Cemetery. In memory of him, the unit of capacitance-Farah was named after him.

Selected from: Physics Teacher's Manual