Topic: Electric Charge and Static Electricity PSSA: C / S8.C.2.1

Objective:  TLW explain how charged objects interact according to the Law of Electric Charges.  TLW describe three ways objects become charged.  TLW compare conductors with insulators.

MI #1: Law of Electric Charges  The Law of Electric Charges states that like charges repel and opposite charges attract.  Protons are positively charged and electrons are negatively charged.  The force between charged objects is electric force, and the region around a charged object in which electric force is exerted is the electric field.

MI #2: How do objects become charged?  Friction – electrons are “wiped” from one object to another.  Conduction – electrons move from one object to another through direct contact.  Induction – charges in an uncharged metal object are rearranged without direct contact with a charged object.

MI #3: Conservation of Charge  When an object becomes charged, the charges are not created or destroyed.  The number of protons and electrons stays the same, electrons simply move from one atom to another.

MI #4: Conductors  Electrical conductors are materials through which electrical charges move easily.  Copper, aluminum, gold, silver, and mercury are all good conductors.

MI #5: Insulators  Insulators are materials through which charges do not move easily.  Plastic, rubber, glass, wood, and air are all good insulators.

MI #6: Static Electricity  Static electricity is an object’s electric charge at rest; it is usually caused by friction or induction.  Electric discharge is the loss of static electricity stored in an object.

So What…? Real Life Application  Understanding conductors and insulators is important in understanding proper electrical safety.