Edison invented the electric light. 1877, Edison began the experiment of transforming arc lamp, and proposed to divide the current and change the 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 highly vacuum glass ball and not easily dissolved. In this way, his experiment returned to carbon wire. He used it day and night, until the first half of 1880, Edison's incandescent lamp experiment was still inconclusive. 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 experiment with incandescent lamps 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 and was replaced. 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.
As we all know, Thomas Edison was a great inventor. He obtained 1093 invention patents in his life, which is the largest number of individual patents since the implementation of the patent system. His famous saying "Genius is 99% diligence and 1% inspiration" has become the motto to inspire people to work hard. It can be said that Edison's contribution has greatly changed human life. Among his many inventions, Edison thought the electric light was the most important, but his favorite was the phonograph. The following is the process of the invention of electric light: the light is a great invention of human beings to conquer the night. /kloc-Before the 0/9th century, oil lamps and candles were widely used for lighting. Before the electric light appeared, kerosene lamps or gas lamps were widely used as lighting tools. Although this broke through the night, it still failed to completely liberate mankind from the restrictions 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.
/kloc-At the beginning of the 9th century, an English chemist made the world's first arc lamp. But this kind of lamp is too strong and can only be installed in streets or squares, which is not used by ordinary families. Countless scientists have racked their brains to make a cheap and durable household lamp. 1879101October 2 1 day, an American inventor finally lit the world's first electric lamp with practical value after long-term repeated experiments. Since then, the inventor's name, like the electric light he invented, has entered thousands of households. He is Edison, who is praised as "the king of invention" by later generations.
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.
In the process of inventing the electric light, Edison carefully summarized the previous failure experience in making electric light. He experienced numerous failures before and after, but he was not discouraged, and finally turned cotton yarn into charred charcoal. He carefully put this carbon wire into the glass bubble, and after testing, the effect is really good. The life of the light bulb was extended by 13 hours, and then it reached 45 hours. 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. Finally, Edison put the carbonized bamboo filament into the glass bulb, and after being electrified, the bamboo filament bulb lit continuously 1200 hours!
Compared with the previous arc lamp, this kind of carbon filament lamp invented by Edison is undoubtedly more practical. Its appearance marks the official beginning of the history of human use of electric light. However, the brightness of this kind of carbon filament lamp is not ideal, the filament manufacturing method is complicated and the service life is not very long. Therefore, scientists all over the world are committed to the improvement of incandescent lamps.
1909, 30 years after the birth of the carbon filament light bulb, Coolidge of the American General Electric Company invented the tungsten filament light bulb. Compared with carbon filament lamp, this kind of electric lamp is a step forward, but its service life is also affected because the tungsten filament is brittle after being electrified.
Ohm and Ohm's Law georg simon ohm was born in Gencheng, He Run. His father was a locksmith. My father taught himself the knowledge of mathematics and physics, and taught Ohm in his teens, which aroused Ohm's interest in science. /kloc-At the age of 0/6, he entered He Run University to study mathematics, physics and philosophy. Dropped out of school due to financial difficulties, and did not finish his doctoral studies until 18 13. Ohm is a man with great talent and scientific ambition. He has been a middle school teacher for a long time. Due to the lack of information and instruments, his research work has brought many difficulties. But he has been persistently conducting scientific research and making his own instruments in a lonely and hard environment.
Ohm studied the current in the wire. He was inspired by the law of heat conduction discovered by Fourier, and the heat flow between two points in a heat conducting rod is directly proportional to the temperature difference between the two points. So Ohm thinks that the current phenomenon is similar to this, and guesses that the current between two points in the wire may be proportional to some driving force between them, which is now called electromotive force. Ohm spent a lot of energy on this research. At first, he used voltaic pile as power supply, but the effect was not good because of the unstable current. Later, he accepted the advice of others and used thermoelectric battery as power supply, thus ensuring the stability of current. But how to measure the current was still an unsolved problem at that time. At first, ohm used the thermal effect of current to measure the current by expanding with heat and contracting with cold, but it is difficult to get accurate results by this method. Later, he combined the current magnetic effect discovered by Oster with Coulomb torsion balance, and skillfully designed a current torsion balance, in which a twisted wire was used to hang a magnetic needle, so that the electrified wire and the magnetic needle were placed in parallel along the meridian direction. Then a bismuth-copper thermoelectric battery is used, one end of which is immersed in boiling water and the other end is immersed in crushed ice. Two mercury tanks are used as electrodes and connected by copper wires. When the current passes through the wire, the deflection angle of the magnetic needle is proportional to the current in the wire. He published the experimental results in 1826. 1827, Ohm summed up his experimental laws into the following formula in the book Mathematical Research of Circuits: S = γ E, where s stands for current; E stands for electrodynamic force, that is, the potential difference between the two ends of the wire, γ is the conductivity of the wire to the current, and its reciprocal is the resistance.
In the early days of the discovery of Ohm's Law, many physicists could not correctly understand and evaluate this discovery, and were doubted and sharply criticized. The research results were ignored and the economy was extremely difficult, which made Ohm depressed. It was not until 184 1 the Royal Society awarded him the honorary copley Gold Medal that the German scientific community began to pay attention.
Ohm also proved in many of his works that resistance is directly proportional to the length of the conductor and inversely proportional to the cross-sectional area and conductivity of the conductor; In the case of constant current, the charge moves not only on the surface of the conductor, but also on the whole cross section of the conductor.
In memory of him, people named ohm's surname as the physical unit for measuring resistance.
I was the first person who came to the earth from an alien and landed on the moon for the first time. Actually, there are two people, besides Armstrong, one is odlum. What Armstrong said at that time: "One small step for me is a big step for all mankind." This has become a famous saying all over the world.
At the press conference to celebrate the success of landing on the moon, a reporter suddenly asked odlum a very special question: "Do you feel a little sorry that Armstrong went down first and became the first man on the moon?"
Under the embarrassed gaze of the audience, odlum replied gracefully: "Ladies and gentlemen, don't forget that I was the first to leave the capsule when I returned to Earth." He looked around and said with a smile, "So I was the first person to come to earth from another planet."
Everyone gave him the warmest applause in laughter.