It’s a mildly annoying occurrence that usually happens when the weather’s dry and you’ve done something like walking across a carpet. While we know how static electricity builds up, the question of why it happens is a surprisingly complicated one, with a weirdly elusive answer.The problem in finding an explanation happens when one of the materials involved is, theoretically, an electrical insulator. There’s no confirmed reason for why an electrical charge should be transferred from or to an insulating material; an insulator, by nature, shouldn’t allow this. The problem is further complicated by the fact that different materials and conductors have different mechanisms for the cause, buildup, and transfer of static electricity.
A static electric shock can also occur between two objects made of identical materials, which makes the phenomenon even stranger. In theory, the difference in properties should be what makes the electrical charge jump from one material to the other, but experiments performed by rubbing two identical materials together have shown that static electricity still passed between the two objects. Currently, there are no satisfactory answers from the fields of physics or chemistry, suggesting that it’s actually a way more complicated phenomenon than either can account for on their own.