What causes static electricity and why do I get shocked?

Static electricity builds up when two materials rub together and electrons transfer from one surface to the other. One object gains extra electrons and becomes negatively charged, while the other loses electrons and becomes positively charged. This commonly happens when you walk across carpet, where friction pulls electrons onto your body. You get shocked when you touch a conductor like a metal doorknob. The excess electrons on your body suddenly rush to the object or vice versa, equalizing the charge difference. That rapid flow of electrons is a small electric current, and you feel it as a brief shock. Dry air makes it worse because moisture normally helps charges dissipate gradually, so static buildup is more common in winter or low-humidity environments.