The story of inventing the telegraph and telephone.

Although people began to develop telegrams as early as the19th century, the invention of practical electromagnetic telegrams was mainly attributed to British scientists Cook, Wheatstone and American scientist Morse. 1836, cook made an electromagnetic telegraph, and applied for the first patent of telegraph the following year. Wheatstone is Cook's collaborator. Morse was originally a first-class American painter. Out of interest, he developed a prototype of the electromagnetic telegraph in 1835, and then in 1838, he invented the "Morse code" composed of dots and dashes according to the signals of current, spark and no spark when disconnected. 1858 July, Scientific American magazine reported: ... As we all know, the British always claimed that the electromagnetic telegraph was invented by their compatriot Professor Wheatstone. On the other side of the Atlantic, the establishment of the telegraph company made more Europeans begin to discuss who was the real inventor of the telegraph. According to The Monitor in Paris, France, Morse was the first person to put the telegraph principle into practice, although he was not the founder.

Before the invention of the telephone, the telegraph was invented, but it had great limitations. It can only convey simple information, which is not convenient for decoding. So, young Bell began to think about how to find a device that can transmit sound directly, so that people can talk directly. Once, while enjoying the music played by the phonograph, it suddenly occurred to him that the phonograph was just an electro-acoustic conversion device. Therefore, Bell began to study the structure and principle of the phonograph carefully, and finally found that the vibration force of sound waves could act on a reed, which converted sound waves into current and then combined with electrode devices, thus forming the initial structure of the telephone. Here, he used analogy for the first time.

However, after testing, it was found that this device could not transmit sound, because the Russian sound wave energy in the air was too weak to drive the reed to vibrate. What shall we do? At this moment, Bell thought of human ears. In order to find out how the human ear hears sound, he borrowed a complete human ear specimen from a friend to study it carefully, and learned that the reason why the human ear can hear sound is that sound waves vibrate the small and thin eardrum first, and then the eardrum drives the larger auditory ossicles to vibrate, thus producing hearing. By analogy, Bell thinks that since this small and thin eardrum can push the larger ossicles, the small and thin diaphragm should also push the reeds to vibrate. So, he and his assistant made two rough prototypes together and conducted a call test. As a result, although they shouted with all their strength, the reeds vibrated, but they could not hear the sound. What's the problem? "They think hard. One day, after intense work, Bell opened the window to breathe fresh air. At this time, melodious guitar sounds came from the distance, which made people relaxed and happy. He couldn't help jumping up. Because the guitar comes with the speaker. He knows that the sound of the guitar can travel far, and it is not enough to rely solely on the vibration of the strings, but also on the role of the speaker, which can also help the speaker improve the sensitivity of the mobile phone. So, Bell immediately began to design the sketch of the speaker, and together with his assistant, he made a phone to help the speaker overnight. Here, Bell opened his mind for the third time by analogy.

The next day, the two of them conducted a new experiment in two rooms separated by 100 meters. Everything is ready. At this time, while adding sulfuric acid to the battery, Bell accidentally spilled some sulfuric acid on his leg, causing him to shout, "Mr. Watson, come quickly!" " "Watson actually heard the voice through the telephone line. In this way, the world's first telephone was born, and the first sentence it conveyed was actually calling for help!

Bell opened his mind by analogy three times in the process of inventing the telephone. It can be seen that analogy is a common and important method in scientific research, which can provide clues, draw inferences and bypass the angle.