 Two types of electric charges  Proton: positive charge  Electron: negative charge  Positive charge of proton = negative charge of electron

 Electrons bond more tightly than protons.  Static electricity: the accumulation of excess electric charge on an object

 When an object becomes charged, charge is neither created nor destroyed  Law of Conservation of Charge: charge can be transferred from object to object, but it cannot be created or destroyed  Usually electrons move from one object to another

 Unlike charges attract each other while like charges repel each other.  The force decreases as the charges get farther apart.  As the amount of charge on either object increases, the electrical force also increases

 Electric field surrounds every electric charge and exerts the force that causes other electric charges to be repelled or attracted.  Represented by arrows that show how the electric field would make a positive charge move  The force of gravity is weaker than electric forces.

 Insulators: a material in which electrons are not able to move easily  Plastics, wood, rubber, glass  Conductors: a material in which electrons are able to move easily  Best electrical conductors: metals

 Rubbing two materials together can result in a transfer of electrons  Charging by Contact: the process of transferring charge by touching or rubbing  Charging by Induction: the rearrangement of electrons on a neutral object caused by a nearby object

 Large static discharge  Static discharge: a transfer of charge between two objects because of a buildup of static electricity

 Detects the presence of electric charges