Static electricity can be induced by rubbing 2 insulators together. One material loses electrons to the other. The one losing electrons becomes positively charged. The other gains electrons to become negatively charged.
When these 2 charged surfaces are brought close enough together, a spark may jump, as electrons leap the gap to cancel out the charge imbalance. This can be experienced as an electric shock.
This applies to any charged surfaces where the imbalance in charge is large enough to make the electrons leap the gap. The spark can be dangerous. Near fuel vapor, as at a service gas station, it can even cause an explosion.
Static electricity
Static electricity is a class of phenomena involving the imbalanced charge present on an object, typically referring to charge with voltages of sufficient magnitude to produce visible attraction, repulsion, and sparks.
Generation
The presence of surface charge imbalance means that the objects will exhibit attractive or repulsive forces. Static electricity can be generated by touching two differing surfaces together and then separating them because of contact electrification and the turboelectric effect. Rubbing two non-conductive objects generates a great amount of static electricity. This is NOT the result of friction. In fact two non-conductive surfaces can become charged by just being placed one on top of the other. Since most surfaces have a rough texture, this takes longer to achieve charging than rubbing. Rubbing objects together increases amount of adhesive contact between the two surfaces. Usually, substances that do not conduct electricity (insulators) are good both at generating, and holding, a surface charge. Some examples of these substances are rubber, plastic, glass, and pith. Conductive objects only rarely generate charge imbalance except, for example, when a metal surface is impacted by solid or liquid nonconductors. The charge that is transferred during contact electrification is stored on the surface of each object. Static electric generators, devices which produce very high voltage at very low current (such as the Van de Graaf generator or Wimshurst machine) and used for classroom physics demonstrations, rely on this effect.
Note that the presence of electric current does not detract from the electrostatic forces nor from the sparking, from the corona discharge, or other phenomena. Both phenomena can exist simultaneously in the same system.
Effects
Natural electrostatic phenomena are most familiar as an occasional annoyance in seasons of low humidity, but can be destructive and harmful in some situations (e.g. electronics manufacturing.) When working in direct contact with integrated circuit electronics (especially delicate MOSFET's), or in the presence of flammable gas, care must be taken to avoid accumulating and discharging a static charge.
Static is a serious nuisance in the processing of analog recording media, because it can attract dust to sensitive materials. In the case of photography, dust accumulating on lenses and photographic plates degrades the resulting picture. Dust also permanently damages vinyl records because it can be embedded into the grooves as the stylus passes over. In both cases, several approaches exist to combat such dust deposition. Some brushes, particularly those with carbon fiber bristles, are advertised as possessing anti-static properties. Also available are handheld static guns which shoot streams of ions to discharge static on records and lenses.
Source: CDX Global & Wikipedia - en.wikipedia.org
