alone or in combination with others, form substances which resist
the flow of electricity. Materials with a high resistance to the
flow of electricity are called insulators. Common insulators include
air, glass, rubber, oil, ceramic, dry paper, and plastics such as
bakelite, Mylar, and polystyrene. A vacuum - the absence of any
material - also prevents the flow of electricity.
be used in electronics to prevent the unwanted flow of electricity,
or to store electrical charges in capacitors. When used to store
a charge, insulators are also known as dielectrics.