What is the most useful invention in history?

Before the electric light appeared, kerosene lamps or gas lamps were widely used as lighting tools. Because this kind of lamp burns kerosene or gas, the black smoke is very thick, the smell is pungent, and it is inconvenient to add fuel, so the lampshade is often scrubbed. More importantly, this kind of lamp is easy to cause fire, which will lead to great disaster. For many years, many scientists have tried their best to invent a safe and convenient electric light.

The lamp is a great invention for human beings to conquer the night. 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, which was divided into two aspects: one was to classify and test 1600 different heat-resistant materials; 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.

/kloc-At the beginning of the 9th century, a British chemist made the world's first arc lamp with 2000 batteries and two carbon rods. But this kind of lamp is too strong and can only be installed in streets or squares, which is not used by ordinary families. Numerous scientists have racked their brains to make a cheap and durable household electric light.

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.

1847 In February, Edison was born in Milan, Ohio, USA. He has only studied in school for three months in his life, but he is studious and diligent in thinking. His invention has created many achievements 1000, such as electric light, phonograph and movie camera, and made great contributions to mankind.

When Edison 12 years old, he was addicted to scientific experiments. After his tireless self-study and experiments, at the age of 16, he invented an automatic telegraph that sends signals every hour. Later, the automatic counting machine, the first practical typewriter, double and quadruple telegrams, automatic telephones and phonographs were invented one after another. Edison was not satisfied with these inventions. 1in September, 878, Edison decided to attack the fortress of electric lighting. He read a lot of books about electric lighting and made up his mind to make cheap, durable, safe and convenient electric lights.

He started the experiment with an incandescent lamp. Put a small piece of heat-resistant thing in a glass bubble, and when the current burns it to a white-hot level, it will give off heat and glow. His first thought was charcoal, so he put a small piece of charcoal wire into a glass bubble, and the glass bubble broke as soon as it was electrified.

"What is the reason?" Edison picked up the carbon wire broken in two and looked at the glass bubble again. After a long time, he suddenly remembered: "Oh, maybe it's because there is air in it. The oxygen in the air helps the carbon wire burn and makes it break immediately!" " So he used his own hand-made air extractor to extract the air from the glass bubble as much as possible. Once it is electrified, it will not go out immediately. But eight minutes later, the light went out.

In any case, Edison finally found that the vacuum state is very important for incandescent lamps, and the key is carbon filament, which is the key to the problem.

So what kind of heat-resistant materials should we choose?

Edison thought about it. Platinum has the highest melting point and strong heat resistance! So Edison and his assistants tried platinum several times, but this kind of platinum with higher melting point prolonged the luminous time of the electric lamp a lot, but it was still not ideal to turn it off automatically and then glow from time to time.

Undaunted, Edison continued his experimental work. He tried various rare metals such as barium, titanium and indium, and the results were not very satisfactory.

After a while, Edison made a summary of the previous experimental work and wrote down all kinds of heat-resistant materials he could think of, a total of 1600.

Next, he and his assistants began to test 1600 kinds of heat-resistant materials in different categories. You can try it, and platinum is the most suitable one. Due to the improved air extraction method, the vacuum degree in the glass bulb is higher and the life of the lamp is extended to 2 hours. But this kind of platinum lamp is too expensive. Who wants to spend so much money on a light that can only last for two hours?

The experimental work fell into a trough, and Edison was very upset. In a cold winter, Edison sat by the fire and looked at the burning coals. He couldn't help saying to himself, "Charcoal ..."

Charcoal bars have been tried. What should I do? Edison felt hot and dry all over, so he pulled off the scarf around his neck. When Edison saw this scarf made of cotton yarn, he suddenly had an idea in his mind:

Yes! Cotton yarn has better fibers than wood. Can you use this material?

He quickly tore off a cotton yarn from his scarf and baked it on the fire for a long time. Cotton yarn turned into charred charcoal. He carefully put this carbon wire into the glass bubble, and after testing, the effect is really good.

Edison was very happy, and then he made a lot of carbon filaments from cotton yarn and did many experiments in succession. The life of the light bulb was extended by 13 hours, and then it reached 45 hours.

As soon as the news spread, it caused a sensation all over the world. The share price of London Gas plunged, and the gas industry was in chaos. People have a hunch that lighting gas lamps will soon become history, and the future will be the era of electro-optics.

Everyone congratulated Edison, but Edison didn't look happy at all. He shook his head and said, "No, we have to find other materials!" " "

"Why, it's been 45 hours?" The assistant asked in surprise. "no! I hope to open 1000 hours, preferably 16000 hours! " Edison replied.

As we all know, it is good to shine for more than 1000 hours, but what materials can we find?

Edison knew what he was doing. According to the nature of cotton yarn, he decided to look for new materials from plant fibers.

So, the marathon experiment began again. Edison experimented with all kinds of plant materials he could find, even horse mane, human hair and beard were used for filament experiments. Finally, Edison chose bamboo as a plant. Before the experiment, he took out a bamboo and observed it with a microscope. He jumped for joy. So, put the carbonized bamboo filament into the glass bulb, and after electrifying, the bamboo filament bulb lights continuously 1200 hours!

Edison finally breathed a sigh of relief, and his assistants congratulated him one after another, but he said seriously, "There are many bamboos in the world, and their structures are different. We should choose them carefully! "

Edison's scientific attitude of pursuing perfection deeply touched him, and his assistants volunteered to visit various places. After comparison, a kind of bamboo produced in Japan is the most suitable, so it is imported from Japan in large quantities. At the same time, Edison started a power plant and set up electric wires. Soon, the American people used this cheap and durable bamboo light bulb.

Bamboo filament lamp has been used for many years. Until 1906, Edison switched to tungsten wire, which improved the quality of the light bulb and has been used ever since.

When people turn on the electric light, they often think of this great inventor, who brought endless light to the darkness. From 65438 to 0979, the United States spent millions of dollars to hold a year-long commemorative event to commemorate the centenary of Edison's invention of the electric light.

Invention dispute

It is generally believed that the electric light was invented by Thomas Edison, an American. However, another American, Henry Goebbels, invented the reliable light bulb with the same principles and materials decades earlier than Edison, and many people made many contributions to the invention of the light bulb before Edison. 180 1 year, British chemist David electrified platinum wire to make it glow. 18 10, he also invented the electric candle, which was illuminated by an arc between two carbon rods. 1854, Henry Goebbels put a carbonized bamboo filament under a vacuum glass bottle to make it glow. Today, his invention seems to be the first incandescent lamp with practical value. The light bulb he tested at that time could last for 400 hours, but he didn't apply for the design patent in time.

1850, the Englishman Joseph Wilson Swan began to study electric lights. 1878, he obtained a British patent for a light bulb powered by carbon wire under vacuum, and started to set up a company in Britain to install electric lights in every household.

1874, two Canadian electrical technicians applied for a patent for electric lamps. They filled helium gas under the glass bubble, and the charged carbon rod would glow. But they didn't have enough financial resources to continue developing this invention, so they sold the patent to Edison at 1875.

Edison tried to improve the filament after buying the patent. 1879, he changed to carbon filament to make a light bulb, which successfully lasted 13 hours. By 1880, his carbonized bamboo filament bulb had been successfully maintained in the laboratory for 1200 hours. But in Britain, Swan sued Edison for patent infringement and won. Edison's electric light company in England was forced to make Swan a partner. But later Swan sold his rights and patents to Edison. In America, Edison's patent has also been challenged. The United States Patent Office once ruled that his invention had a criminal record and was invalid. Finally, after years of litigation, Edison obtained the patent right of carbon filament incandescent lamp.

China's first electric light.

1882 at 7: 00 p.m. on July 26th, a generator in Shanghai started to turn and lit the 15 electric light. This is an important moment in the history of Shanghai civilization and a new era in the history of China electric lights. Since then, electric lights have been lit on the land of China.