Static Electricity CHAPTER 16: SECTIONS 1-4

Static Electricity  Charge that remains in one area.  Ben Franklin ( )  “Elektron” =amber in Greek carries a negative charge  Glass carries a positive charge *negative and positive are arbitrary  Rules of charge  Likes repel  Unlikes attract  No net charge can be created or destroyed

Charge on an Atomic Level  Negative net charge is an excess of outer electrons  Positive net charge is a deficiency of outer electrons  Static charge is a result of a transfer of outer electrons between materials.

Dry days are best for sustaining a static charge.  Water molecules are polar and can attract loose electrons.  On a wet day charge will “LEAK” away because of this attraction to the water molecules in the air.  On a dry day there is less moisture in the air and there are much fewer water molecules to “steal” electrons away.  BEST DAYS to build up a charge is a dry winter day. WHY?

Two Basic Types of Materials  Conductors  Lots of loosely bound electrons that are free to move about within the material  Metals (silver, copper, and gold are the top 3)  Aqueous salts and acids/bases (ionic or polar covalent)  Humans (why?)  Insulators  Tightly held electrons that are not free to move.  Wood, glass, plastic  Nonpolar covalent (sugar)  Semiconductors  Few loose electrons  Silicon or Germanium doped with arsenic, boron, antimony

How to charge an object  Rubbing 2 objects together to transfer electrons from one to the other.  Bringing an neutral object 1. In contact with a charged object (CONDUCTION) 2. In close proximity to a charged object (INDUCTION) * No charge is created or destroyed during these processes!

Conduction  Physical contact with a charge object allowing a transfer of electrons to or away from a neutral object.  Net charge acquired by the neutral object is the same as the charging object.  How is it done? How is it done?

Induction  Close proximity to a charged object that causes separation of charges in the neutral object.  Net charge acquired by the neutral object is the opposite of the charging object.  Can create a net charge the same as the charging object if GROUNDING is used.  How it works? How it works?