STUDENT RESOURCE PAGE 3.1
conductor a material current can pass
insulator a material that current cannot
pass through easily
A good conductor has low resistance
Insulators block the ﬂ ow of current.
to the ﬂ ow of electric charges. Metals,
Plastic and rubber, like that used to
like aluminum, gold, and copper,
cover wires, are examples of insulators.
are good conductors. Solutions that
ion an atom with an electric charge
contain ions also are good conductors.
When dissolved in water, molecules
A material that resists, but does not
of table salt break apart, forming ions
stop, the ﬂ ow of electric charges is a
of sodium and chlorine. These ions have
poor conductor. The ﬁ lament of a light
electrical charges that allow them to
bulb is an example of a poor conductor.
carry electric current through the water.
Pure water is also a poor conductor of
ELECTRICITY • SECTION 3 CONDUCTORS AND INSULATORS