People can dance on the stage under the light. Can small pieces of paper dance on the plastic board with the accompaniment of music? Let's do a little experiment. First, we prepare some scraps of paper and a plastic stick, put the scraps of paper on the table, rub the plastic stick back and forth many times, and then immediately suck the scraps of paper away with the rubbed plastic stick. At this time, a miracle appeared. Small pieces of paper began to dance in beautiful clothes Why is this? In fact, this is the role of static electricity. How did static electricity come from? It turns out that all substances are composed of molecules, and molecules are atoms composed of negatively charged electrons and positively charged protons. Under normal circumstances, an atom has the same number of protons and electrons, so it is not charged. However, once the electrons surround the nucleus, they will leave the original A atom and invade other atoms. The phenomenon that BA atom is positively charged due to insufficient number of electrons is called the phenomenon that cation B atom is negatively charged due to increased number of electrons is called anion. The reason for the uneven distribution of electrons is that electrons are derailed by external forces, which contain all kinds of energy, such as kinetic energy, thermal energy and chemical energy. Any two objects of different materials can contact and then separate to generate static electricity, which is called triboelectrification. In the dry and windy autumn of our daily life, we often encounter this phenomenon: when we undress and sleep at night, we often hear a crackling sound in the dark, and when we meet and shake hands under blue light, our fingers will suddenly feel the sting of our fingertips when they touch each other, which is shocking. When I get up in the morning to comb my hair, my hair tends to float and get more and more messy. When we pull the door handle to turn on the tap, we will get an electric shock and often make a crackling sound. This is static electricity that happens to the human body, and some of it will cause harm to the human body. Knowing the principle of static electricity, we can try our best to avoid its harm to people, and we can also use this principle to manufacture machinery and equipment to serve people.