Wind is the sound produced by airflow caused by wind. The sound of water flow is the sound produced by water hitting the air. All kinds of sounds in the air, no matter what form they take, are caused by the vibration of objects: when you beat the drum, you can hear the drum sound and feel the vibration of the drum surface; People can speak because of the vibration of vocal cords in the throat; The whistle and roar of a jet plane are caused by the vibration of gas when it exhausts. In a word, the vibration of an object is the source of sound, and the object that makes sound is called the sound source.

In physics, sound is produced by the vibration of an object, and the object that emits sound is called a sound source. The number of times an object vibrates in one second is called frequency, and the unit is hertz. People's ears can hear the sound of 20 Hz-20hz-20000Hz. The most sensitive sound is 1000Hz-3000Hz.