Static Electricity Physical Science 8 th Grade

Electric Charge All solids, liquids, and gases are made of tiny particles called atoms. Protons, and electrons posses electric charge, while neutrons have no electric charge.

Positive and Negative Charge Two types of electric charges Protons = Positive Charge Electrons= Negative Charge Atoms are electrically, neutral, which means they behave as if they have no charge at all. Atoms normally have equal numbers of protons and electrons. Sometimes an atom will gain an electron and become negatively charged. Sometimes an atom will lose an electron and the atom will then become positively charged.

Electrons move between objects Ex. Balloon on your hair The buildup of electric charges on an object is called static electricity. Protons cannot be moved from one object to another because they are held tightly with the neutrons in the nuclei of atoms. It is always electrons that are gained or lost when an object becomes charged, and never protons.

Electric Forces Electric Force is the law that: Like charges repel Opposite charges attract The strong nuclear force is even stronger than electric force. This strong nuclear force is the glue that holds protons and neutrons together in the nucleus.

Electric Fields The electric force acts on charged objects even though they may be some distance apart. Ex. Magnets Electric charges exert a force on each other at a distance through an electric field, which exists around every electric charge.

Insulators A material in which electrons cannot move easily from place to place is called an insulator. Ex. Plastic, wood, glass, and rubber

Conductors Materials that are conductors allow electrons to move through them more easily. Electrons placed on the surface of a conductor spread out over the entire surface. Best conductors: copper, silver, iron The human body is a conductor.

Induced Charge The separation of positive and negative charges due to an electric field is called an induced charge. Ex. Doorknob and hand This rapid movement of excess electrons from one place to another is an electric charge Ex.–spark or flash

Grounding Earth is a conductor, and because it is so large, it can absorb an enormous quantity of excess charge. The process of providing a pathway to drain excess charge into the Earth is called Grounding. Electrons move from Earth to the object to make it electrically neutral.