Please give me a brief introduction of David.

David and Dalton are contemporary chemists. David, younger than Dalton 12 years old, is enthusiastic, good at speaking and skilled in experiments. When he was young, he made many amazing moves and became a world-famous chemist. He showed the significance of science in the period of capitalist development with practical actions, and made outstanding achievements in improving the social status of science. From Apprentice to Scientist 1778 65438+February17 Humphrey David was born in the countryside near Penzance, England. Father is a woodcarver. He entered school at the age of five and was a naughty student. The two pockets of his clothes, one containing fishing gear and the other containing various minerals, were found in a mining area not far from home. He has an amazing memory. He not only remembers stories, but also vividly tells stories told by others or books read. Every holiday party, adults like to let him recite poems, while friends beg him to tell stories, which invisibly cultivates his eloquence. When he finished primary school, his father sent him to Penzance to study and put him in foster care with his grandfather. There is something novel in the city that attracts him, that is, the strange change of substances when doctors prepare drugs. Since then, he often secretly hid in the top floor, using bowls, cups and plates as utensils and learning to do experiments. Occasionally, he got into trouble in the experiment and was laughed at by his grandfather, but this didn't weaken his interest in chemical experiments at all. 1794 father died, and the family was even more difficult. In order to make a living, the eldest son David was sent to a local doctor named Praz as an apprentice. This job suits David's interests very much. On the one hand, he acts as a doctor's assistant, nursing patients and learning the skills of practicing medicine. On the other hand, he must prepare all kinds of drugs every day, prepare pills and potions by dissolving and distilling, and really operate chemical experimental instruments. At this time, he realized that he had little knowledge, so he began to study hard and read lavoisier's Introduction to Chemistry and other chemical works. Through learning, the content and purpose of his experiments are clear, and he tries every experiment mentioned in his works as much as possible. He tried to borrow all the good books and read them hungrily. When he meets a knowledgeable person, he will take the initiative to ask for advice. Just then, there was a man named Gregory. Watt (the second son of the inventor james watt) came to Penzance for investigation. When David heard the news, he went to the door for advice. Watt likes this smart and studious young man very much and enthusiastically helps him answer questions. In this way, during his four-year apprenticeship, his knowledge grew rapidly. From 65438 to 0798, introduced by Watt, David came to Bristol and worked as an administrator in the laboratory of the Institute of Gas Therapy opened by Dr. Pados. At that time, many gases were discovered one after another. The human body absorbs oxygen and feels fresh and comfortable; Ammonia gas is strongly irritating. How do various gases affect people's physiological functions? What gas can be used to treat diseases? These are the concerns of many doctors. The research institute founded by Pados is dedicated to exploring this problem. Pados knows chemistry and is good at medicine. David is satisfied with the better study and experiment opportunities here. After a period of time, Pados found that David's experimental skills were excellent and he was a promising talent, so he offered to fund David to study medicine at the university. However, at this time, David became more and more interested in chemistry and made up his mind to engage in chemical research all his life, so he declined Pardo's kindness. 1799 In April, something happened in gas therapy, which made David famous: David made nitrous oxide (also known as nitrous oxide). Some people think it's poison gas, and Pados thinks it can treat paralysis. How determined David is to try it himself. Many friends advised him that it was too dangerous. The adventurous character made David throw himself into the experiment at once. Afterwards, he wrote on the record: "I know this experiment is very dangerous, but from its nature, it may not be life-threatening. ..... After inhaling a small amount of this gas, I feel dizzy and infatuated. I feel very comfortable after inhaling my limbs again. Slowly, the muscles are weak, the image of the outside world in the brain is disappearing, and all kinds of novel things appear. After a while, people screamed and jumped wildly ... "After waking up, he felt very uncomfortable. Through personal experience, he knows that this gas obviously cannot be absorbed into the human body in excess, but a small amount can be used as an anesthetic in surgery. Then he wrote a pamphlet about the process of the experiment, his personal feelings and the nature of laughter. After reading this booklet, many people were attracted by David's introduction and curiously took inhaling laughing gas as fashion. David's fame spread in laughter, and many people rushed to know David. He was only 22 years old at this time. Thomas Thompson, a physicist who is famous for his thermodynamic research, came to England on 1799. In order to popularize scientific knowledge, he established the Royal Society for Popular Science in London through private fund-raising. This scientific group does not carry out teaching activities, but regularly holds various lectures to teach new scientific discoveries and their applications. The association has a professorship and provides a well-equipped laboratory for professors. Almost all the professors hired were famous scientists at that time. 180 1 At the beginning, David was recommended by many people and was hired by the Royal Society of Science. Count Lunford had long heard of David's talent, but when they first met, David was dressed in rags and looked very formal, and Lunford was disappointed. Considering that he is very young, he was appointed as an assistant in chemistry and in charge of the laboratory. Soon David's rich knowledge and superb experimental skills made Lunford realize that his initial impression was an illusion, so David was promoted to associate professor in the sixth week after taking office, and then to professor in the second year, becoming the second chemistry professor. In the lecture on science, David achieved unexpected success with his extraordinary intelligence and eloquence. People swarmed in, sometimes as many as 1000 people, and the venue was packed. He soon gained a reputation as an outstanding speaker and became a celebrity in London. As someone commented at that time: "His speech gave people a feeling and was warmly praised, which was completely beyond imagination. Many scientists, writers, college students and those solemn gentlemen and fashionable ladies are eagerly crowded into the venue, watching the simple operation of this weak young man and listening to the expressive narrative. His profound knowledge, vivid metaphors and ingenious experiments surprised people and won great appreciation. Many people complimented him, invited him to dinner and gave him gifts, which almost kept David busy. The enthusiasm of the audience was a great encouragement to David, who studied chemistry more diligently. Get up early every day, read and write for 2 hours before breakfast, work in the laboratory in the morning 10 until 4 pm, and have lectures or various social activities in the evening. Keep going day after day. Achievements and honors have not disappointed diligent people. 12 years, David made a contribution to electrochemistry, established the hydrogen theory of acid, discovered iodine, invented mine safety lamp and made arc lamp. 1303 was elected member of the royal society, 1807 was elected secretary of the royal society, and 1820 was elected president of the royal society. 1826 broke down from overwork, 1827 died in Geneva at the age of 5 1. The fruitful achievements of electrochemistry 1799 Italian physicist Volta invented the battery that converts chemical energy into electric energy, which made human beings obtain practical continuous current for the first time. 1800, Nicholson and karis in Britain successfully electrolyzed water with a voltaic cell, which made people realize that electricity can be used in chemical research. Many scientists have done various experiments with electricity. David is thinking, since electricity can decompose water, what effect will it have on salt solutions and solid compounds? In the busy work of the Royal Society of Science, he began to study the electrolysis of various substances. First of all, he quickly became familiar with the structure and performance of voltaic cells, and assembled a particularly large battery for experiments. Then he chose wood ash (i.e. caustic potash) as the first research object because lavoisier thought that the main components of soda ash and wood ash were unclear. At first, he made caustic potash into saturated aqueous solution for electrolysis. As a result, oxygen and hydrogen are obtained at the two poles of the battery, but there is still no other gain by increasing the current intensity. After careful analysis of the reasons, he thinks that water is the reason. Then he switched to molten caustic potash. Under the action of current, the molten caustic potash has changed obviously, and purple flames appear constantly where the conductor contacts caustic potash. The unknown substance that produces purple flame is too hot to collect. After summing up the experience again, David finally succeeded. At the academic report meeting of 1807 royal society, David introduced this way: expose a piece of pure caustic potash to the air for a few minutes, and then put it on a special platinum plate, which is connected to the negative electrode of the battery. The anode of the battery is in contact with caustic potash through platinum wire. After electrifying, I saw caustic potash slowly melting, and then I saw the part connected with the positive electrode boiling, producing a lot of bubbles. At the contact of the negative electrode, I only see a substance that looks like a ball, has a metallic luster and looks like silver. As soon as the ball was produced, some of it burned. With the sound of explosion and purple flame, the rest of the surface gradually became dull, and then it was wrapped in a white film. This small spherical substance has been tested and I know it is what I am looking for. Through the experiment, David further realized that this substance could not sink when put into water, but jumped quickly on the water, hissed and then appeared purple sparks. These strange phenomena led him to conclude that this is a newly discovered element, which is lighter than water and decomposes water to release hydrogen. Purple flame is hydrogen combustion. Because it is extracted from wood ash, it is named potassium. The success of wood ash electrolysis made David more confident in this method, and then he electrolyzed soda in the same way to obtain another new metal element. This element comes from soda, so it is named sodium. After six weeks of intense experiments, David was so tired that his eyes were sunken and his face was pale, but he persisted with strong perseverance. 1807165438+1October 19 He supported the introduction of the discovery of potassium and sodium in academic reports. The stormy applause and warm congratulations made David feel very happy. When he got home, the disease finally knocked him down. The fever caused by overwork kept him on the brink of death for nine weeks. Thanks to the public's concern and the doctor's day and night care, the condition has finally improved. The illness didn't dampen his spirit and enthusiasm at all. When he was a little better, he came to the laboratory again and started a new study. From March 1808, he went on to electrolyze lime and bitter soil (magnesium oxide). At first he still used the same method as electrolytic soda, but it didn't work. Several other methods have been adopted, but they are all unsuccessful. At this time, the Swedish chemist Betzerius wrote to tell David that he and Ding Peng had electrolyzed the mixture of lime and mercury and successfully decomposed lime. According to this suggestion, David successfully mixed lime and mercury oxide in a certain proportion to make calcium amalgam, and then heated to evaporate mercury, thus obtaining silvery white metallic calcium. Then magnesium, strontium and barium are prepared. The flower of electrochemical true colors bears rich fruits in David's hands. Lavoisier once thought that all acids contained oxygen. This view was once very popular. Accordingly, hydrochloric acid should contain oxygen, and chlorine is not an element but an oxide. However, chemists try their best not to find oxygen from hydrochloric acid or chlorine, but to make alkali metals by electrolysis. David, who succeeded in the experiment of alkaline earth metals, began to study this difficult problem. Through a series of carefully designed experiments, David confirmed that chlorine is an element, hydrochloric acid contains no oxygen, and hydrogen is an indispensable element in all acids. After a period of testing, people accepted David's wrong view that the hydrogen element of acid replaced the oxygen element of acid. Since then, people have a correct understanding of the nature of acid. David lived in an era when the British industrial revolution was booming. Coal is widely used as fuel instead of wood, which greatly stimulates the mining of coal mines. But gas explosions often happen, which makes miners shudder like the devil. Mine owners and miners formed the "Association for Preventing Coal Mine Disasters". They heard David's name and asked him for help. David immediately went to the mine to analyze this explosive gas, proving that combustible gas has a certain ignition point, and the ignition point of gas is very high, so it is only possible to ignite the explosion at high temperature, usually because of the ignition lighting in the mine. In view of this, David made a mine safety lamp and personally carried it to the most dangerous mining area for demonstration. David's invention was quickly popularized, which effectively reduced the gas explosion and was welcomed by miners. At this time, it was suggested that David keep the patent of this invention, but he refused. He solemnly declared: "I believe what I have done is in line with humanitarianism. "This shows the purpose of his scientific research. David made outstanding achievements in studying boric acid, saltpeter, diamond, discovering iodine and inventing arc lamp. In addition to these achievements, there are two other works that are often praised by later generations. The Royal Society for Popularization of Science founded by Renford is maintained by private donations, but it is not easy to raise such donations. Although the quality of professors' lectures has an impact on donations, it determines the direction of the college. According to Lunford's original idea, he mainly engaged in the display of new achievements in popular science and applied science. David and others asked the association to do some scientific experiments for some influential groups and actively undertake some influential research projects, thus expanding the work content of the association. For example, during the period of 1802- 18 12, British food imports decreased due to the French Revolution. In order to help the development of agriculture, David opened a course of agricultural chemistry in the association. From 180 1 to 1806, David also studied tanning technology. 18 15 years, he invented the mine safety lamp. In this way, the association will no longer simply provide lectures, but also serve as a scientific research institution. It not only carried out popular science propaganda, but also strengthened the connection between science and production, demonstrated the significance of science and improved the social status of science. The great scientist Faraday was discovered by David. Thanks to David's help, Faraday came to the laboratory of the Royal Society of Science, from a poor bookbinder to David's assistant. Although David suppressed Faraday in his later years because he was jealous of his achievements, he had to admit that David trained him and created the necessary conditions for Faraday to complete his scientific achievements in the future. So David discovered and trained such an outstanding talent as Faraday, which in itself is a great contribution to the cause of science.