How did Edison invent the incandescent light bulb?

1. The eve of the electric light era

In ancient Greek mythology, human beings were created by the god Prometheus. He also acts as a teacher for mankind. He teaches mankind any knowledge that is useful to mankind and can make mankind satisfied and happy. Likewise, humans thank and repay him with love and loyalty. But Zeus, the supreme god, requires humans to worship him and to dedicate the best things to him. Prometheus' various actions offended Zeus.

As punishment for him, Zeus refused to give humanity the final item needed to complete their civilization - fire. But Prometheus thought of a way. He used a long fennel branch to steal fire when the blazing sun chariot passed by and brought it to mankind. Fire changed human history, steam drove the industrial revolution, and electricity ushered in a new era.

The electric light is the most famous invention of the late 19th century.

Among Edison's 2,000 large and small inventions, the most important and brilliant inventions are the electric light and the power distribution system. It was Edison who brought light to mankind. When Edison began researching electric lights, natural gas lights were commonly used in homes. The invention of natural gas had a history of 70 years at that time. It replaced the previous oil lamps and candles and developed rapidly.

However, to use natural gas lamps, every household must install a natural gas pipeline to supply natural gas, so it can only be used in cities, and most people in the United States cannot use it. On the other hand, research into using electricity for lighting is also ongoing. Before the advent of electric lights, people had initially mastered knowledge about electricity. The first person to start this research was British scientist David. In 1808, David connected 2,000 batteries for an experiment and tied carbon rods to the wires extending from the two poles of the batteries. The moment the carbon rods touched the iron wire, a strange phenomenon occurred: an intense light was produced between the two carbon rods, which was incomparable to kerosene lamps and natural gas lamps. So David immediately thought of electric lights. He wanted to use electricity for lighting. After long-term and unremitting research, such a lighting lamp was invented, which is called an arc lamp.

But the arc lamp is very rough, and the carbon strips are very easy to wear and need to be replaced frequently. It will go out in an hour. At that time, most households still used kerosene lamps or gas lamps. It cannot be spread to every household, but it is precisely because of this that the research on inventing more convenient electric lights has been put on the historical agenda.

2. The boyhood of the "King of Inventions"

Edison was born in Mylan, Ohio, USA in 1847. His father ran a lumber processing plant, and Edison was the youngest of four children. Edison, the inventor king, was a child who was curious about everything since he was a child. In order to hatch goslings, he hatched goose eggs like a mother goose; in order to make people fly into the sky, he made his friends drink acid, which almost caused a disaster. When Edison was a child, he was regarded as a "mentally retarded child" by his school teachers because he liked to seek his roots and was taken back by his mother. Therefore, Edison's entire school life lasted only three months.

Edison learned a lot from his mother, more than the average elementary school curriculum. Under his mother's enthusiastic education, little Edison's knowledge improved rapidly. Once, my mother bought little Edison a book called "The School of Science". There are a lot of scientific experiments recorded in that book. After little Edison read it carefully, he completed every experiment. From then on, Edison gradually became an experimental maniac. His childhood room was littered with scientific books and experimental equipment.

When Edison was 12 years old, a steam locomotive appeared in his hometown. Due to family financial difficulties, little Edison heard the news about the recruitment of newspaper sellers on the train and immediately applied for the job. From then on, he became the newspaper courier on the train. After selling newspapers, Edison would spend the rest of his time reading. Little Edison thought of another brilliant idea. He asked the familiar captain to turn a small part of the coach into his own room. He moved all the experimental equipment from his home up there and opened a laboratory there.

Because the Civil War was breaking out in the United States at that time, people were particularly concerned about current affairs. Little Edison also had a very good business selling newspapers on the train. Two or three years later, he edited a "Pioneer Weekly" on the train, and even the British "Times" reprinted its news. In his spare time, he studied hard and conducted various scientific experiments fascinatedly. One day, because the train was shaking too much, a bottle of yellow phosphorus fell to the ground, causing a fire. Fortunately, people put out the fire in time and put out the fire. The captain became angry, threw all his instruments and medicines out of the car, and slapped little Edison three times, making him deaf in his left ear.

At the age of 15, Edison saved the son of stationmaster and telegraph operator McKenzie from a car accident on the railway. In order to repay Edison, McKenzie promised to teach him telegraph technology. Soon, he was made a telegraph operator at the station. At the age of 16, Edison invented the automatic telegraph machine. It was because of this automatic telegraph machine that he was dismissed as "lazy". In the following years, Edison changed careers many times, and was often fired many times because his inventions and reforms were considered "not doing his job properly."

When Edison was 21 years old, he went to Boston.

Among the more than 1,000 invention patents he obtained throughout his life, the first one was born in Boston. He patented an "automatic electronic voting recording machine" in Boston.

In 1870, Edison purchased a workshop in Newark, New Jersey, and began producing the stock ticker he invented. This time Edison was successful and made a lot of money. In 1876, 29-year-old Edison founded a new research center, the "Monroe Institute" in Menlo Park, 40 kilometers away from New York. This initiative not only had immeasurable significance in Edison's career, but it was also the first industrial scientific research institution in the United States and the world. It marked the beginning of collective research and set the stage for the establishment of large-scale industrial research institutions in the United States and other countries around the world. Set an example.

3. Edison’s family life

Mary Stilwell was Edison’s first wife. She met Edison while working in a Newark factory and she knew the young man she would marry well. In 1884, Mary unfortunately died of typhoid fever.

Mina Miller was Edison's second wife. She married Edison when she was 20 years old. At first, her parents did not support the marriage because of Edison's age difference with her. Edison taught Miner Miller how to use electrical codes so that the two could communicate in secret languages.

Mary let her husband work, dress, and eat as he pleased. Meena, however, worked hard to correct her husband's careless demeanor, pointing out that smoking and spitting were behaviors not allowed in civilized society.

4. Launch an attack on electric lighting

Edison thought: "It would be great if every household could use electric lights!"

September 1878, Edison really launched an attack on the fortress of electric lighting. As soon as the news spread, it immediately caused a sensation throughout the United States and also spread to the United Kingdom, causing London Gas stocks to plummet.

Edison began to engage in intense scientific experiments. He started by experimenting with incandescent lamps. The principle of this kind of lamp is to put a small piece of heat-resistant material in a glass bulb and connect it to a power source. When it burns to a white-hot level, the glass bulb will glow due to heat. Based on this principle, Edison believed that in order to conduct a good experiment, he must first find a suitable heat-resistant material.

One night, Edison sat at his desk, turned on the gas lamp, took out a pen and paper, and wrote down all the heat-resistant materials he could think of. Finally, he counted more than 1,600 kinds. The next day, he arranged manpower to prepare these materials. Then, he conducted experiments in different categories; at the same time, he used his brains on the structure of the electric lamp, constantly improved the extraction method, and strived to achieve an absolute vacuum inside the glass bulb. During this period, Edison racked his brains, spent all his energy, forgot to eat and sleep, and worked day and night, but he always failed to achieve the desired effect after trying again and again.

It was not until October 1, 1879, that I saw a report in the "Scientific American" magazine that Swann used carbon filaments to make filaments that he re-developed the carbon filament light bulb. He also wanted to build a system of generators, wires and cables that would bring electricity to everyone, like a network of gas pipes. Edison's work on electric lights received research fees provided by many capitalists, allowing Edison to devote himself to research.

5. Experiments with various materials

In 1978, Edison had already conducted research on electric lights. At that time, charcoal was burned with paper, cut into thin strips, and then energized to emit light. But that was done in the air, and the carbon wire burned out immediately because there was no vacuum valve at the time and it was impossible to create a vacuum environment. In addition, Edison tried platinum wire, chromium, boron and other materials, but they were all unsatisfactory. It wasn't until the vacuum valve was invented that a vacuum environment could be created. Edison tried the carbon wire and platinum wire again, and found that the platinum wire was resistant to high temperatures in a vacuum. After continuous research, Edison successfully developed a 25-watt vacuum light bulb using platinum wire in 1879. This achievement was patented in April 1879. However, due to the high price of platinum, the production cost of this kind of light bulb is high, which is not conducive to popularization. So Edison returned to the study of carbon wire.

Making a conducting core with huge resistance is the first condition to weaken the current, but making a conducting core from carbon is not a simple matter. Edison racked his brains for this but had no good solution. But one day, he saw a thread dropped on the ground and suddenly had an epiphany. Edison cut nylon wire to a certain length, coated it with coal tar and charcoal powder, and then baked it in a nickel horseshoe-shaped mold. As expected, thin charcoal threads were produced. Edison then spent two days bending the carbon wire, putting it into the glass bulb, and carefully removing the air inside.

October 21, 1879, was an extremely solemn and tense day. Everyone held their breath and watched Edison connect the wires with trembling hands and turn on the switch. The electric lights flickered on, and cheers rang out in the institute. It was this day - the long-awaited electric lights began to illuminate people's lives. The electric light lasted 45 hours before going out, waking them up as if from a dream.

Edison proudly walked into the patent office holding his early invention of the light bulb. The invention of a continuous light source changed the way people lived and worked. The key to Edison's success was finding a filament that could glow inside the bulb without burning out completely.

The news of Edison's invention of the electric light shocked the world and brought joy to the world.

Anyone who has spent a blackout night will understand this joy intimately. But Edison did not stop and continued to work on improving electric lights. In order to develop a more durable wick, Edison tried thousands of plant fibers and changed various processing methods such as roasting, burning, and compressing, but still had no effect.

The God of inspiration always comes by chance. One day in the summer of this year, Edison was immersed in working in the laboratory. He was sweating profusely from the heat, so he picked up a bamboo fan to cool off. He was fanning, and suddenly, he stared at the fan intently. After a while, he tore the fan into pieces and put them under a microscope to observe carefully. Looking at it, he couldn't help but jump up with joy and said: "Hey! Why didn't I think of using carbonized bamboo silk?"

So he immediately jumped up and extracted fibers from the bamboo strips. Once baked, it becomes a strong wick. Edison sealed a wick made of bamboo filaments into a light bulb, extracted air, and applied electricity. The luminosity is brighter than the first bulb and the lifespan is extended by several days.

In this another success, Edison gained strength. In order to find a more durable wick, he tried almost all kinds of bamboo. By 1880, the life of an incandescent light bulb with a carbonized bamboo filament exceeded 600 hours for the first time.

"You should be satisfied now!" the assistants also said happily.

After that, Edison continued to research and continuously improved the quality of electric lights. Later, he changed the bamboo filament light bulb into a tungsten filament light bulb, which is the light bulb we use now. For this little light bulb, Edison spent 12 years, conducted thousands of experiments, and devoted a lot of effort.

Edison's invention of the electric light went through a tortuous process. The first light bulbs had a very short service life, mainly because the filament was easily burned out. The temperature of the electric light filament was as high as 2300°C to 3000°C. Generally, metal would melt at this temperature. After many experiments, tungsten, the metal with the highest melting point, was finally selected to make the filament. The melting point of tungsten is 3410°C. Although tungsten has a higher melting point, it still cannot make the bulb durable. The reason is that tungsten metal easily reacts with oxygen at high temperatures. After tungsten is oxidized, it becomes tungsten trioxide.

Later, people took out the air from the light bulb, so that the inside of the light bulb was in a vacuum state, so that the tungsten filament would not be oxidized, and the life of the light bulb was extended.

After the news of Edison's invention of the electric light spread around the world, countries all over the world requested to use this achievement. But there was no power plant at that time, so it could only be powered by voltaic batteries. Each voltaic cell is as big as a pillow, and 100 of these cells are needed to light a lamp. Therefore, the electricity used to power the lamp cannot come from such a huge power source, and it cannot be used in ordinary households.

Edison saw the need to invent a generator and thought he needed to develop a method of transmitting electricity. So the research institute that developed light bulbs became the Electric Power Research Institute. Edison ordered steam equipment with excellent performance, improved the generator, and established the world's first central power station in New York in 1882. This power station contains power generation equipment and transmission equipment further improved by Edison. The electricity generated by this generator can be used to power 800 nearby electric lights through wires. A year later, the number available had increased to 1,700. Human life has changed greatly since then.

In the history of electricity, Edison’s contribution was by no means just the electric light. Within one year of 1880, Edison obtained 32 patents related to electric lights, 7 patents for power distribution, 5 patents for electric light parts such as lamp sockets, and 3 patents for generators, which shows the extent of his contribution.

6. Edison Era

After inventing the electric light, Edison continued his invention career. He has 1,300 invention patents for trams, cameras, batteries, and telecommunications machines. Among so many inventions not one was weapons or gunpowder. This is the best proof of Edison's love for human happiness and peace. "Invented for the happy life of mankind", this was Edison's lifelong belief. Edison's notes show that although he was untrained, he understood many scientific principles. He has very scientific research methods that we can learn from. Edison was both an "old-fashioned" inventor who liked to spend a lot of time working in the laboratory, and a modern businessman who was able to organize professional work groups and invest profits in research. When he was born, the world was still in the "Dark Ages"; when he died, the world had entered the age of mechanical technology and electronics. When Edison was 80 years old, on May 30, 1929, U.S. President Hoover hosted a celebration of the 50th anniversary of Edison's invention of the electric light. Two years later, on October 21, 1931, this great inventor ended his glorious life. On this day, the entire United States paid tribute to the "Menlo Park Magician". People turned off all lights and electrical equipment for one minute, and the entire United States was darkened. History will always remember the great Edison era.