What causes static electricity?

I. Micro-causes (internal factors)

According to the theory of atomic physics, matter is in an electrical equilibrium state when it is electrically neutral. Due to the contact of atoms of different substances, the gain and loss of electrons cause the substance to lose balance and generate static electricity.

Matter is composed of molecules. Molecules are composed of atoms. Atoms are composed of negatively charged electrons and positively charged protons. Under normal circumstances, the number of protons and electrons of an atom is the same and the balance is positive and negative, so it appears uncharged to the outside.

When two different objects come into contact with each other, one object loses its charge and the electrons are transferred to the other object, making it positively charged; while the other object that gets some remaining electrons is negatively charged. If the charge is difficult to neutralize during the separation process, the charge will accumulate and the object will be electrostatically charged. That is, an object is electrostatically charged when it comes into contact with other objects.

Macro reasons (external causes)

① Friction between objects generates heat and excites electron transfer.

② Contact and separation between objects produce electron transfer.

③ Electromagnetic induction causes an imbalance in the surface charge of an object.

④ The combined effect of friction and electromagnetic induction.