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, totaling 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 ..."
Charcoal bars have been tried. What should I do? Edison felt hot all over, so he pulled down the scarf around his neck. Seeing this scarf made of cotton yarn, Edison 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.
(1) Information: The United State