1898, French physicist AntoineHenriBecquerel discovered that uranium-containing substances can emit a mysterious ray, but failed to reveal the mystery of this ray. Mary and her husband Pierrecurie)*** * * both undertook the work of studying this kind of radiation. They separated and analyzed pitchblende under extremely difficult conditions, and finally found two new elements in July 1898 and February 12.
To commemorate her native Poland, she named one element polonium and the other element radium, which means "radioactive substance". In order to prepare pure radium compounds, it took Madame Curie another four years (MarieCuI7e, 1867- 1934) to extract1o0mg of radium chloride from several tons of pitchblende residue, and the relative atomic mass of radium was preliminarily determined to be 225. This simple figure embodies the hard work and sweat of the Curie couple.
1In June, 903, Madame Curie took "Research on Radioactive Substances" as her doctoral thesis and obtained a doctorate in physics from the University of Paris. In June165438+1October of the same year, the Curies were awarded the David Gold Medal by the Royal Society. In February 65438, together with Bekkerel, they won the 1903 Nobel Prize in Physics.
1906, pierre curie died in a car accident. This heavy blow did not make her give up her persistent pursuit. She fought back her grief and redoubled her efforts to complete their beloved scientific career. She continued her husband's lecture at the University of Paris and became the first female professor at the university. 19 10, her famous book on radioactivity was published. She cooperated with Mou and others to analyze pure metal radium and measure its properties. She also measured the half-lives of oxygen and other elements and published a series of important works on radioactivity. In view of the above great achievements, she won the Nobel Prize in chemistry at 19 1 1, becoming the first great scientist to win the Nobel Prize twice in history.
The founder of radiation science, who suffered from scientific hardships, died unfortunately on July 4, 1934 on/kloc-0 because of years of efforts. She devoted her glorious life to the scientific cause of mankind.
Bell is the man who invented the telephone. He was born in England on 1847. When he was young, he and his father taught the deaf together. He once wanted to make a machine to let deaf people see sound with their eyes.
1873, Bell, who became a professor at Boston University in the United States, began to study the device of transmitting multiple telegrams on the same line-multiplex telegrams, and he sprouted the idea of using electricity to transmit people's voices to far places and let people thousands of miles away talk face to face. So bell began to study the telephone.
That was June 2nd, 1875. Bell and his assistant Watson are experimenting with multiple telegrams in two rooms respectively. An accidental accident inspired Bell. In Watson's room, there is a spring stuck to the magnet of the telegraph. When Watson pulled it away, it shook. At the same time, Bell was surprised to find that the spring on the telegraph in his room vibrated and made a sound. It is the current that transmits vibration from one room to another. Bell's mind suddenly broadened. He thought: If a person speaks to a piece of iron, the sound will cause the iron to vibrate; If an electromagnet is placed behind the iron sheet, the vibration of the iron sheet will inevitably produce large and small currents in the electromagnet coil. This fluctuating current travels far away along the wire, so won't the same vibration and sound appear on similar equipment in the distance? In this way, the sound travels far away along the wire. Isn't this the dream phone!
Bell and Watson made the telephone according to this new idea. In an experiment, a drop of sulfuric acid splashed on Bell's leg, causing him to shout, "Mr. Watson, I need you, please come to me!" " "This sentence reached Watson's ear by telephone through wires, and the telephone succeeded! 1On March 7th, 876, Bell became the patentee of telephone invention.
Bell obtained 18 patents in his life and 12 patents in cooperation with others. He envisions burying telephone lines in the ground or hanging them in the air, and connecting them to houses, villages and factories ... so that you can make phone calls directly from anywhere. Today, Bell's vision has become a reality.
3. The invention of electric light
The lamp is a great invention for human beings to conquer the night. 19th century ago, people used oil lamps and candles for lighting, which broke through the night, but still failed to completely liberate mankind from the restriction of the night. Only with the birth of the generator can we light up the world with all kinds of electric lights, turn night into day, expand the scope of human activities, win more time and create wealth for society.
It was the American inventor Edison who really invented the electric light to make it shine. He is the child of a railway worker. He dropped out of school before finishing primary school and made a living by selling newspapers on the train. Edison is an extremely diligent man. He likes to do all kinds of experiments and make many exquisite machines. He is particularly interested in electrical appliances. Ever since Faraday invented the electric motor, Edison was determined to make electric lights and bring light to mankind.
Edison made a detailed test plan after carefully summarizing the previous failure experience in manufacturing electric lamps, and conducted experiments in two aspects: one was to classify and test more than 600 different heat-resistant materials of/kloc-0; The second is to improve the vacuum pumping equipment to make the bulb have a high vacuum degree. He also studied the new generator and circuit shunt system.
Edison tested 1600 kinds of heat-resistant luminescent materials one by one, but the linear energy of platinum wire is good, but the price of platinum is amazing, so we must find a more suitable material to replace it. 1879, Edison finally decided to use carbon filament after many experiments. He sprinkled carbon powder on a piece of cotton silk, bent it into a horseshoe shape, heated it in a crucible, made it into a filament, put it in a bulb, and then pumped the air out of the bulb with an air extractor. It can be used continuously for 45 hours when the light is on. In this way, the first batch of carbon filament incandescent lamps in the world came out. 1879 On New Year's Eve, Lopark Street where Edison Electric Company is located is brightly lit.
In order to develop electric light, Edison often worked in the laboratory for more than ten hours a day, and sometimes experimented for several days. After he invented carbon fiber, he experimented with more than 6000 kinds of plant fibers. Finally, he chose bamboo filaments, burned them in a high-temperature closed furnace, and then processed them to obtain carbonized bamboo filaments, which were put into the light bulb, thus improving the vacuum degree of the light bulb again, and the light bulb could be continuously lit for 1200 hours. The invention of electric light once caused natural gas stocks to plummet 12% in three days.
After Edison, 1909, American Ke Renqi invented tungsten wire instead of carbon wire, which greatly improved the efficiency of electric lamp. Since then, electric lamps have leapt to a new level, and fluorescent lamps, iodine tungsten lamp and other lamps have mushroomed on the lighting stage.
Lights turn darkness into light and make the world more dazzling and colorful.