What causes a static electricity discharge?

Answer 1

What is Static Electricity?

At it's simplest, static electricity is an electrical charge
that cannot move. It is created when two objects or
materials that have been in contact with each other are
separated. When in contact, the surface electrical
charges of the objects try to balance each other. This
happens by the free flow of electrons (negatively
charged particles) from one object to the other. When
the objects separate, they are left with either an excess
or a shortage of electrons. This causes both objects to
become electrically charged.

If these charges don't have a path to the ground, they
are unable to move and become "static". If static
electricity is not rapidly eliminated, the charge will
build up. It will eventually develop enough energy to
jump as a spark to some nearby grounded or less
highly charged object in an attempt to balance the
charge. A good example of this in everyday life is
lightning. Lightning is produced by a discharge of
electricity from one cloud across an air gap to another
cloud or between a cloud and the earth.