Introduction to electrostatic ping pong: When visitors press the power button, high voltage will be applied to the positive and negative plates. Due to the effect of electrostatic induction, the suspended metal balls are also charged. At this time, due to the principle of mutual attraction and repulsion of charges of opposite sexes, the metal ball will interact with the two plates, making a "ping-ping-pong-pong" sound while swinging back and forth.