Conductors

Local Charge  When an item is charged the charge transfer takes place at the point of contact.  Other areas are unaffected.       

Insulator  If the charges stay in place the material is an insulator.  A vacuum is a perfect insulator.  Materials are never perfect insulators. Some charge movesSome charge moves Example: human skinExample: human skin       

Conductor  If the charges redistribute the material is a conductor.  Good conductors allow charges to move freely. Metals: copper, iron, etc.Metals: copper, iron, etc.  Some materials change from conductors to insulators under different circumstances. TemperatureTemperature LightLight    

Ions  Atoms are made of protons and electrons bound together. Generally neutralGenerally neutral  When electrons are added removed the atom becomes an ion. Ions are charged atoms.Ions are charged atoms.  Impurities in an insulator can create ions and form a conductor. Salt in waterSalt in water        

Lightning Bolt  Air is a poor conductor.  If too much charge builds up between the air and the ground some air can ionize.  The ionized air can carry electricity in the form of lightning. Cornell University Extension photo

Induction  Charge can be induced in another object without touching the object.

Shape and Charge  Excess charge on a conductor will always move to the outer surface. Like charges repel Charges free to move  Charges will concentrate at pointed regions on the surface. next         