Why can ancient people use paper and bamboo tubes to transmit information?

Homemade telephone can be said to be the embryonic form of modern telephone. The ancestors of China people learned to make earthen telephones very early, which can be said to be the inventors of the rudiments of telephones. Homemade telephones are easy to make. Use two bamboo tubes or paper cups, kraft paper and a thread. One end of a bamboo tube or paper cup sealed with kraft paper is open, and cotton threads are connected through holes. The wire end is fixed at the center of the bottom of kraft paper or paper cup of microphone.

Two people each take a microphone and straighten the cotton thread, so they can talk, and it can be effective within 100 meters. One person speaks at the microphone, and the other person listens with his ears at the microphone. Sound can travel far through the vibration of cotton thread. Some experts have suggested that China declare local telephones as world intangible cultural heritage.

The habit of making local calls

Making "local calls" is a unique "love game" for boys and girls of the Dai family in Lujiangba, Baoshan City, Yunnan Province.

During the Spring Festival, Naive Tiny Mao and Tiny always make up themselves and come to some established "old places" for parties. Singing and dancing, talking and laughing, carrying out entertainment and social activities. Making "local calls" is one of the interesting "reserved programs"

"Earth phone" is a necessary prop for playing games. It is made by sawing a pair of bamboo tubes with thick cups, both ends covered with pig urine bubbles, and gradually tapering a small hole in the middle, and then connecting the two bamboo tubes with a cotton thread several feet long.

Refer to the above? Baidu Encyclopedia-Local Telephone