Humphrey. H.Davy (1778 ~ 1829) is an American chemist. He taught 180 1 year chemistry at the Royal College of England, and 1803 was elected as a member of the Royal Society of England. 1807, as the secretary of the institute; 18 12 was knighted and published Principles of Chemical Philosophy. 18 13 years, he appointed Faraday as his assistant. Since then, Faraday has gradually become a famous scientist, which is another important contribution of David to science.
Humphry davy-safety miner's lamp
David got the title of Lord and married a rich widow. A few months later, they went on their honeymoon. David brought a mobile lab and an assistant-Michael? Faraday traveled to Europe 18 months. When they returned to the motherland, it coincided with the announcement of national mourning by Britain.
At that time, several terrible explosions occurred in the mines of Newcastle and Caldi, killing thousands of miners. In order to ensure the safety of operation in the mine, the coal mine company awarded a special prize to the inventor who could invent the safety lamp for the mine. The general manager of the company specially asked David to help them solve this problem. The mine sent him "explosive gas" for experiment, which is a dangerous gas. In fact, its composition is an explosive mixture of two volumes of hydrogen and one volume of oxygen. David and his assistant Faraday have repeatedly studied the properties and characteristics of this gas and the conditions under which it causes destructive explosion when burning.
Their research work lasted almost a whole year. They thought of introducing the air needed to keep the miner's lamp burning into the lamp with some thin tubes, and then exhausting the gas out of the lamp through these thin tubes. When the pipeline is thin enough, even if there is such explosive gas in the mine, it will not cause explosion because of its existence and contact with the lamp flame. They repeatedly observed the change of flame size when using different pipes, and conducted a series of systematic experiments. At the beginning of 18 16, a safety miner's lamp was finally designed successfully.
This miner's lamp is very effective. David replaced the glass cover of the miner's lamp with a metal net with a small mesh, so that the flame would not be exposed and burn the gas, but the gas could freely pass through the hole. Soon, this lamp was widely used in coal mines, and miners got rid of a deadly threat underground.
David won the langford Medal for inventing and designing the safety miner's lamp.
1820, David was elected President of the Royal Society. On February 20th, 1826 1826, David was elected honorary academician of Petersburg Academy of Sciences.
Although David's research involves all aspects, he has never relaxed his research on electricity, because some phenomena about electricity have not been satisfactorily explained at that time, and the nature of electricity has not been clearly studied, which requires repeated experiments. Although he and Faraday, the famous Danish physicist Oster and other scientists have made some achievements, this is only the beginning, so David has been exploring the secret of electricity almost all his life. David has a laboratory specializing in electrical phenomena, which contains all kinds of measuring instruments, special instruments and other instruments for measuring the conductivity of objects.
The resistance of conductors to current varies with different conductors, and resistance can be used as an additional characteristic of conductor substances. David summed up the results of the long-term experiment. However, Faraday raised another objection. He said, "There is no doubt that the resistance is different, but at present I can't see its regularity." David thinks: "Indeed, it is very complicated to generalize different substances. However, for a single substance, the solution to the problem is much simpler. We have obtained some information in this regard. " So Faraday went to the table and wrote a few numbers, which fully proved that the resistance of the substance they studied depends on the length and cross section of the conductor. When the temperature rises, the resistance will increase.
Humphry davy gas research company
British physicist humphry davy, a Bedouin, established a gas research institute in Clifton to study the physiological effects of various gases on human body, hoping to find some gases with medical effects and which gases are harmful to human body. The institute needed an excellent chemist, so Bedo hired David. The first gas that David studied was nitrous oxide. American chemist SamuelMitchill believes that nitric oxide is harmful to human body, and anyone who inhales this gas will be fatally hit. David disagrees with Mitchell. After repeated experiments, he found that nitrous oxide was harmless to human body. After inhaling this gas, people will feel intoxicating, so David suggested that nitrous oxide can be used for surgery. David's paper on the effect of nitrous oxide on human body was published in 1800, which made a comprehensive evaluation of the anesthetic effect of nitrous oxide and was considered as the best anesthetic ever. In addition, he also studied the physiological effects of various gases including nitrogen dioxide and carbon monoxide on human body. Obviously, it is very dangerous to study these two gases, but David insisted on doing it and encouraged his brother John David to do this risky experiment.
David showed strong quantitative experimental research ability when doing gas research, and his volume analysis experimental technology was very clever. His research work is characterized by high labor intensity, but he can get experimental results at an amazing speed, and he shows special creativity in adapting existing instruments to new research topics. He is not interested in repeating and proving other people's discoveries, but he shows great perseverance in innovation.
Humphry davy electrolysis method
Humphry davy David's works on the respiratory function of nitrous oxide made him famous, which made his chemical career have a good start. After the news that AlessandroVolta invented the electric reactor was announced, Nicholson and karis reported that they used Volta reactor to decompose water into hydrogen and oxygen. After learning about these new discoveries, David immediately devoted himself to this research field and published a paper. For example, in the research, David not only used the Volta reactor, an advanced experimental tool at that time, but also kept the clearest head all the time to explore whether there were still shortcomings in the previous practice and theory. Volta always thought that the current in the stack was produced after two different metals came into contact, but David was the first chemist to realize that this "contact theory" was insufficient. He believes that current is not only produced by contact, but actually by chemical reactions in the stack. He also pointed out that in electrolytic cells, compounds are decomposed into their components due to the action of current, and David's view has been widely valued and supported in France and Germany.
David also found that if there was no oxygen in the water between the metal sheets, the stack could not work well, and concluded that the redox effect of zinc and copper (or silver) was the reason for the current generated by zinc-silver or zinc-copper stack. It is further inferred that the stacking effect will be better if nitric acid is used instead of water or salt solution in the stacking. David also used an electric pile, in which electrodes were placed in two containers, so that the solutions in these containers were connected by wet asbestos ropes.
The above research results were published in 180 1, from which people can see David's innovative spirit again. This year, David was selected as a lecturer at the Royal College. He was happy to write to his mother: "You have probably heard of the Royal Academy established by Count Langford and other nobles, haven't you? This is a very gorgeous building, but talented people are not organized to play a prominent role. Count Langford suggested that I work there. " In fact, as David said, the Royal Academy of Sciences has become one of the most famous scientific institutions in the world since it absorbed fresh blood like David (David later discovered his assistant Faraday and elected him to the Royal Academy of Sciences). The purpose of the Royal College is to spread knowledge, provide technical training for most people, encourage the invention and improvement of new and useful machines, and hold lectures regularly to publicize the above results. During David's tenure, such speeches were more frequent. He is an excellent speaker himself, and he has successfully attracted a large number of college students, scientists and science lovers. So, in a very short time, David became a celebrity in London. In London, science suddenly became fashionable, and at the same time, the Royal College became a British scientific research center and an important place to teach science.
When David first arrived at the Royal College, his lectures were all about technical topics. 1805, he won the copley Prize for publishing a paper on tanning. From 1802 to 18 12. This is the first attempt to apply chemistry to agriculture. Before JustusVonLiebig's work on agricultural chemistry was published, David's lecture was always regarded as a pioneering work in the field of agricultural chemistry.
1806, David gave a lecture in Bakelin with the research results of electrochemistry, the content of which was the study of electrolytic water. He pointed out that when electrolyzing pure water, the products of throat 1 are hydrogen and oxygen produced according to the theoretical ratio, which is consistent with the experimental results and conclusions obtained by Bezerius. However, other chemists who study electrolyzed water point out that acid and alkali will appear around the electrode when electrolyzed water, and hydrogen and oxygen cannot be produced according to the theoretical ratio when electrolyzed. David answered the above questions with his precise experiments. He pointed out that pure water redistilled in a silver instrument is put into a gold or agate container and electrolyzed in a hydrogen atmosphere (this can avoid the reaction between hydrogen and oxygen in the new ecology and nitrogen in the air), and only hydrogen and oxygen are produced. When water is electrolyzed, the reason why acid and alkali are produced around the electrode is that the purity of water is not enough (including salt). In the six years after Nicholson and karis's experiment of electrolyzed water was published, no chemist noticed the above problem, but David explained it. He also proposed electrolysis as a chemical analysis method and discussed the transfer of substances in solution during electrolysis. He found that when two cups were filled with electrode and conductive solution respectively, then the third cup was filled with neutral salt solution, and each cup was filled with turmeric or litmus indicator, and then the solutions in the three cups were connected with asbestos rope, the color of the indicator near the electrode would change during electrolysis. If barium chloride solution is added to two cups with electrodes, the cup with sulfuric acid is placed between the two cups, and the solutions in the three cups are connected by asbestos rope, barium sulfate precipitation will occur in the middle cup during electrolysis, which proves that there is material transfer during electrolysis. David is also a supporter of Bezayrie's dualism. They divided chemical elements into positive and negative ones. When they combine, they form a neutral substance, which can be decomposed by current polarization.
1807, David described the process of separating metal potassium and sodium in Backelin lecture. The year before last, he began to study chemical elements with a new method (that is, electrolysis). Lavoisier once thought that chemists are not concerned with the ultimate substances that can never be decomposed as elements, but with those objects that cannot be decomposed by any means at present. At that time, some people regarded alkali, soda and potassium oxalate (potassium carbonate extracted from plant ash) as objects that could not be decomposed, but lavoisier refused to include them in the list of objects that could not be decomposed. Inspired by lavoisier, David wanted to separate these chemical elements from potassium carbonate, sodium carbonate and alkali by electrolysis. He made a bold prediction: "If chemical combination has the characteristics I once boldly imagined, then no matter how strong the natural electricity (binding force) of the elements in the object is, it can't be infinite, and the power of human artificial instruments seems to be infinitely increasing. I hope that the new method (referring to electrolysis) will enable people to discover the real elements in objects. "
David used 250 pairs of metal plates to make the largest voltaic pile at that time, thus generating powerful current. At first, he electrolyzed with a saturated solution of potassium carbonate, but he didn't separate metal potassium, only hydrolyzed water. 1807, 10 On June 6th, David decided to change this practice and electrolyze molten potassium carbonate. However, dry potassium carbonate is not conductive, and it must be exposed to the air for a period of time to make its surface absorb a small amount of water before it can have conductive ability. Then, put the potassium carbonate with wet surface on a small platinum plate, and the platinum plate is connected with the negative electrode of the battery through wires. The platinum wire connected to the anode of the battery was inserted into potassium carbonate, and the whole device was exposed to air. After electrifying, potassium carbonate began to melt and the surface boiled. David found that there was strong light on the cathode, which produced metallic particles similar to mercury near the cathode. Some particles burn immediately after formation, producing bright flames and even explosions. Some particles are oxidized to form a white film on the surface. David reversed the current in the electrolytic cell and still found silvery white particles on the cathode, which may also burn and explode. David was ecstatic when he saw this amazing discovery. He jumped up in the room and wrote in his notebook: "Important experiments prove that potash is decomposed."
David threw this metal particle into the water. At first, it whirled quickly on the water, making a hissing sound, and then it burned to give off a lavender flame. He confirmed that he had discovered a new alkali metal element. Because this metal is made of potassium oxalate, it is named potassium. Then he made metallic sodium, magnesium, calcium, strontium, barium and nonmetallic elements such as boron and silicon by electrolysis.
In the process of studying alkali metals and alkaline earth metals, David encountered another problem. He found that alkali is an oxide, but if alkali contains oxygen, it makes him puzzled, because he has long known lavoisier's theory of acid and oxygen, and lavoisier thinks that oxygen is the origin of acidity, and all acids contain oxygen. Is the great chemist lavoisier wrong, or is David's understanding of alkali incorrect?
Humphry davy-Breaking the Argument
When studying the chemical properties of tellurium, humphry davy David found that hydrogen telluride is an acid, but it contains no oxygen, which makes him wonder whether oxygen exists in all acids. In order to find more evidence, David began to study hydrochloric acid. According to lavoisier's point of view, in 1774, a new gas produced by CarlWilhelmScheele through the reaction of hydrochloric acid with manganese dioxide is hydrochloric acid oxide, which consists of oxygen and another unknown free radical, and hydrochloric acid oxide is a combination of this free radical and more oxidation. However, David tried his best to get oxygen from hydrochloric acid oxide. He said, "Even if the charcoal is burned into a white-hot state by the electric pile, it can't make any changes in the hydrochloric acid oxide gas and hydrochloric acid gas. I have repeated this experiment many times and the results are the same, so I suspect that there is oxygen in these substances. " Gay-Lussac and Lauiz Jacques Steiner also conducted the same experiment, thinking that there is no oxygen in hydrochloric acid oxide, on the contrary, hydrochloric acid oxide may have the nature of elements. But they firmly believe that the great chemist lavoisier's point of view is not wrong, so although they have opened the channel to discover that chlorine is a chemical element, the result is still nothing. Only David claimed that as long as there was no water, all the reactions of hydrochloric acid oxidation would not produce oxygen, and he thought it was best to regard hydrochloric acid oxidation as an insoluble substance. In his view, facts show that the views held by lavoisier and the French school of chemistry are beautiful and satisfactory on the surface, but from the knowledge we have now, it is only a theory based on assumptions. So David confirmed with irrefutable facts that the so-called "hydrochloric acid oxide" is by no means a compound, but a chemical element. He named this element chlorine. He believes that chlorine can help combustion like oxygen, and oxygen does not have to exist in the oxidation reaction. He also pointed out that all exothermic reactions are oxidation reactions. David's views well developed lavoisier's combustion theory.
Humphry Davy- Summary of Contributions
Lavoisier opened agricultural universities in 1 and 1802.
2, the invention of coal mine safety lights during the industrial revolution, the main energy was coal. At that time, the coal mine was poorly equipped and gas explosions often occurred. 18 15 (UK) Establish the Coal Mine Disaster Prevention Association. That year, David spent three months to solve the problem of gas explosion-covering the miner's lamp with metal wire, and the metal wire conducted away the heat energy, so that the combustible gas in the mine could not reach the ignition point and would not explode.
Coal mine safety lights were used until 1930s (and then gradually replaced by battery lights).
3. Obtaining alkali metals and the like by electrolysis. 1807 David electrolyzed 250 pairs of zinc-copper primary batteries in series as power supply to obtain sodium and potassium, and 1808 electrolyzed to obtain magnesium, calcium, strontium, barium, silicon and boron.
4, determine the chlorine as a simple substance David found that hydrogen telluric acid is oxygen-free, thus doubting lavoisier's argument that acid contains oxygen. In 1774, Schiller of Sweden prepared Cl2 by the reaction of MnO2 _ 2 and HCl. Under the influence of lavoisier's viewpoint, because the product is acidic when dissolved in water, he thinks that chlorine is "hydroxyl hydrogen chloride gas". Gay-Lussac found that the gas reaction without oxygen in "oxidized hydrochloric acid gas" conformed to Jane's law, but he firmly believed lavoisier's view. In 18 10, David reacts with coke, sulfur, phosphorus, metal and "oxidized hydrochloric acid gas" respectively, and no oxygen-containing products are produced. So he declared that as long as there is no water, all the reactions of "oxidizing hydrochloric acid gas" will not produce oxygen, thus defining it as simple substance-chlorine.
Humphry Davy- Personal Achievement
Electrolytic caustic soda Humphrey? David's life achievements are very rich. He began to study chemistry as an apprentice at the age of 17, and read a lot of chemistry books, which made him quick-thinking, creative and practical, and made brilliant achievements. In chemistry, his greatest contribution in his life is to open up a new way to prepare metal elements by electrolysis: that is, to study the chemical effect of electricity with voltaic cells, to electrolyze caustic soda that could not be decomposed before to prepare potassium and sodium, and later to prepare alkaline earth metals such as barium, magnesium, calcium and strontium. Later, he made boron by strongly reducing potassium; Gases have also been deeply studied; Anesthetics and irritating nitrous oxide have been discovered, which is very useful for the development of surgery. He proved that chlorine is a chemical element through experiments. It is pointed out that the indispensable element in acid is hydrogen, not oxygen, which corrects lavoisier's viewpoint that "acid must contain oxygen". He invented the coal mine safety lamp to benefit the underground workers.
All these achievements are the result of his lifelong efforts. David is very ill. Prior to this, he went to Geneva and Switzerland for recuperation many times, but his condition has never improved. This time he lives in the suburbs of Geneva. In May this year, his wife and brother John? David is here. But David is so weak that he can only wait for the power of life to fade away. 1May 29, 829, great scientist Humphrey? David passed away.