Why do we experience static shocks?
Static electricity refers to the buildup of electric charge on the surface of objects. The static charges remains on an object until they either bleed off to ground or are quickly neutralized by a discharge. Although charge exchange can happen whenever any two surfaces come into contact and separate, a static charge will only remain when at least one of the surfaces has a high resistance to electrical flow (an electrical insulator). The effects of static electricity are familiar to most people because we can see, feel and even hear the spark as the excess charge is neutralized when brought close to a large electrical conductor (for example a path to ground), or a region with an excess charge of the opposite polarity (positive or negative). The familiar phenomenon of a static 'shock' is caused by the neutralization of charge.
Many people ask about shocks experienced when they touch the door, filing cabinet, lift, or other metal object.
Static electricity is generated whenever two materials are in contact with each other. All materials are made of electrical charges in the material atoms. In the universe there are equal amounts of negative electrical charge (electrons) and positive charge (protons). These generally try to stay in balance of equal amounts at every location.
However, when two materials are in contact, some of the charges redistribute by moving from one material to the other. This leaves an excess of positive charge on one material, and an equal negative charge on the other. When the materials move apart, each takes it's charge with it. One material becomes charged positively, and the other negatively.
If the materials are able to conduct electricity away the charges will dissipate and eventually recombine. In this case, static electricity effects may be too small to be noticed. However, if the charges are separated faster than the material can dissipate them, the amount of electrostatic charge builds up....