Madame Curie
Madame Curie made a comprehensive investigation of known chemical elements and all compounds, and made an important discovery: an element called thorium can automatically emit invisible rays, which shows that the phenomenon that an element can emit rays is not only the characteristics of uranium, but also the same characteristics of some elements. She called this phenomenon radioactivity, and called elements with this property radioactive elements. The radiation they emit is called "radiation". According to the experimental results, she also predicted that minerals containing uranium and thorium must be radioactive; Minerals that do not contain uranium and thorium must not be radioactive. The instrument inspection completely verified her prediction. She excluded those minerals that did not contain radioactive elements, concentrated on those that were radioactive, and accurately measured the radioactive intensity of elements. In the experiment, she found that the radioactive intensity of a pitchblende is much higher than expected, which shows that the mineral in the experiment contains a new unknown radioactive element, and the content of this element must be very small, because this mineral has already been accurately analyzed by many chemists. She resolutely published her findings in the experimental report and tried to prove it through experiments. At this critical moment, her husband, pierre curie, also realized the importance of his wife's discovery, and stopped studying crystals to study this new element with her. After several months' efforts, they separated a substance mixed with bismuth from the ore, which was far more radioactive than uranium, and was later listed as polonium No.84 in the periodic table of elements. A few months later, they discovered another new element and named it radium. However, the Curies did not immediately get the joy of success. When they got a little compound of new elements, they found that the initial estimate was too optimistic. In fact, the content of radium in ore is less than one millionth. Because this mixture is extremely radioactive, substances containing trace radium salts are hundreds of times more radioactive than uranium.
The road to science has never been smooth. For centuries, the discovery of polonium and radium and the characteristics of these new radioactive elements have shaken some basic theories and concepts. Scientists have always believed that atoms of various elements are the smallest unit of matter, and atoms are inseparable and unchangeable. According to the traditional view, the radiation emitted by radioactive elements such as polonium and radium cannot be explained. Therefore, both physicists and chemists are interested in Madame Curie's research work, but they all have doubts in their hearts. Chemists in particular are more rigorous. In order to finally confirm this scientific discovery and further study the properties of radium, the Curies must separate more and purer radium salts from asphalt ore.
All the unknown worlds are mysterious. At the beginning of the study of separating new elements, they didn't know any chemical properties of the new elements. The only clue to find a new element is that it is highly radioactive. Based on this, they created a new chemical analysis method. But they have no money, no real laboratory, only some simple instruments they bought or designed themselves. In order to work efficiently, they conducted research separately. The characteristics of radium are determined by Mr. Curie's experiments; Madame Curie continued to refine pure radium salt.
Where there is a will, there is a way! Any mystery of nature will be revealed by those who stubbornly solve it. At the end of 1902, Madame Curie extracted one tenth of extremely pure radium chloride and accurately determined its atomic weight. Since then, the existence of radium has been confirmed. Radium is a natural radioactive substance, which is extremely difficult to obtain. Its shape is white crystal shining like fine salt. In spectral analysis, it is different from the spectral line of any known element. Radium is not the first radioactive element discovered by human beings, but it is the most radioactive element. Using its powerful radioactivity, we can further discover many new properties of radiation. Therefore, many elements can be further applied to practice. Medical research has found that laser rays have different effects on different cells and tissues, and those rapidly multiplying cells are quickly destroyed once they are irradiated by radium. This discovery makes radium a powerful means to treat cancer. Cancer is made up of cells that reproduce very quickly, and the damage caused by laser rays is far greater than that caused by surrounding healthy tissues. This new treatment method was quickly developed all over the world. In France and France, radium therapy is called Curie therapy. The discovery of radium has fundamentally changed the basic principles of physics, which is of great significance for promoting the development of scientific theory and its application in practice.
Edison
Edison began the experiment of transforming arc lamp in 1877, and put forward the idea of dividing current to turn arc lamp into white light. The experiment should reach a satisfactory level. It is necessary to find a substance that can burn to white heat as a filament, and can withstand high-temperature combustion of more than 2000 degrees 1000 hours. At the same time, the usage should be simple, can withstand the impact of daily use, and the price should be low. It is also necessary to turn on and off one lamp without affecting the turn-off of any other lamp and maintain the relative independence of each lamp. This was a very bold idea at that time, which required great efforts to explore and experiment. As for the materials used for silk, Edison first experimented with carbonized materials, and then experimented with platinum-iridium alloy with high melting point. He also made 1600 different experiments on fine ores and seedlings, and the results failed. But at this time, he and his assistants have made great progress, knowing that incandescent filament must be sealed in a glass ball with high vacuum and not easy to melt. In this way, his experiment returned to carbon wire. He used it day and night in the first half of 1880, but Edison's incandescent lamp experiment still had no result. One day, he tore a bamboo filament tied to the edge of a banana fan in the laboratory into filaments and devoted all his energy to carbonization. Only the carbonation experiments of plants have reached more than 6000 kinds. It's been three years since his experiment notebook has more than 200 books and more than 40,000 pages. He works eighteen or nine hours a day. At three or four o'clock every morning, he only sleeps under the experimental table with two or three books on his head. Sometimes he sleeps on the stool three or four times a day for only half an hour at a time.
By the first half of 1880, Edison's incandescent lamp experiment was still inconclusive, and even his assistants were discouraged. One day, he tore a bamboo filament tied to the edge of a banana fan in the laboratory into filaments and carbonized it into filaments. The result is better than all previous experiments. This is Edison's first incandescent electric lamp-bamboo filament electric lamp. This kind of bamboo filament lamp lasted for many years. It was not until 1908 that tungsten was invented as a filament to replace it. Edison began to develop alkaline batteries after this, which was very difficult, and his research spirit was even more amazing. This kind of battery is used to provide power. He and a selected assistant have studied hard for nearly ten years and experienced many hardships and failures. One moment he thought he had reached his destination, but the next he knew he was wrong. But Edison never wavered and started again. It took about 50,000 tests and 150 test notes to achieve the goal.