Science Fair Project Encyclopedia Electrical conductivity is a
measure of how well a material accommodates the transport of
electric charge. Its SI derived unit is the siemens per metre,
(A2s3m-3kg-1) (named after Werner von Siemens). It is the ratio
of the current density to the electric field strength. This
applies also to the electrolytic conductivity of a fluid.
Conductance is an electrical phenomenon where a material
contains movable particles with electric charge, which can carry
electricity. When a difference of electrical potential is placed
across a conductor, its movable charges flow, and an electric
current appears. A conductor such as a metal has high
conductivity, and an insulator like glass or a vacuum has low
conductivity. A semiconductor has a conductivity that varies
widely under different conditions, such as exposure of the
material to electric fields or certain frequencies of light. SI
electricity units - electrical conduction for a discussion of
the physical origin of electrical conductivi