Electrostatics

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					             Chapter 9
         Electrostatics
Sections 9.2, 9.3, 9.4, 9.5, 9.6,
                  9.7, 9.8, 9.10
9.2 Electrical Nature of Matter
   Static electricity is a natural
    phenomena

   The study of static electricity is
    elctrostatics.
Continue 9.2
   When two objects are rubbed together,
    they can become charged with
    electricity. This charge can remain
    “static,” which means the charge stays
    where the rubbing took place. This is
    static electricity.
9.2…
    Law of electric charges:
        like charges repel one another,
        unlike charges attract one another,
        Charged Objects attract neutral object.
    TEST for electric charges
1.    Observe what the object does near an
      object with a known charge.
How to test for charges
    We use electroscopes to test for charges.
1.   Observe what the object does near an
     object with a known charge. Ex. If you hold a
     balloon near a pith ball that you know is
     negatively charged and it repels from it
     …you would know that the balloon is neg.
2.   Charged objects will attract both opposite
     charges and neutral!!
3.   Charged objects will repel like charges!!
9.2 Electrical Nature of Matter
   Ensure you know table 1 p. 273,
    “A model for the electrical nature of
    matter”
   Complete questions 1, 2, & 3. p. 273
9.3 Charging by Friction
   Charging by friction: transferring an
    electric charge from one substance to
    another by a rubbing action.
       One objects shares electrons with another.
        One is +/ one is -. Think of rubbing a
        balloon on your head.
Electrostatic Series
   Be able to read the electrostatic series and
    know its purpose!
       The objects at the top will “give up” some of their
        electrons to the ones underneath them. The
        greater the distance, the greater the charge is.
       Example: locate hair and plastic on the series.
        When you comb your hair(friction) the hair will
        give up some of its electrons to the comb. Result:
        hair + comb -
Continue 9.3 friction
   HowStuffWorks Videos "Transferring
    Charge: Friction“
   Complete questions 1, 2, 3 & 4 p.275
9.5 Transferring Charge by
Contact
   Charging by contact occurs when electric
    charge is transferred from one substance to
    another because they touch.
       One object shares its charge with another – both
        will have the same charge.
   refueling incident
9.6 Insulators and Conductors
   An electrical insulator is a substance in
    which electrons cannot move freely from
    atom to atom.
   An electrical conductor is a substance in
    which electrons can move freely from one
    atom to another.
   Insulators & Conductors explained
   Answer 1,2,3, & 4 p.281
9.7 Discharging Electrically
Charged Objects
   Answer 1,2, & 3 p. 283
9.7 Discharging Electrically
Charged Objects
1.   If an object has all excess charges removed,
     it is said to be discharged.
2.   When a charged object is grounded to
     Earth, it shares its charge with the entire
     Earth.
3.   Discharge at a point is a method of
     discharging airplanes.
4.   Objects can discharge over time by simple
     exposure to air.
9.8 Induction
   Transferring electric charge from one
    substance to another without direct contact is
    charging by induction.
   The shifting of electrons within a particle due
    to a force from another object is induced
    charged separation.
   Charging by Induction Video
   Answer 1,2,3, & 4 p. 287
Induction checklist... know:
   object with a charge gets close to a neutral
    object - doesn’t touch
   charges it with OPPOSITE charge of charged
    object
   usually temporarily charged - when charged
    object leaves, electrons redistribute
   cam be permanently charged if connected to a
    grounding wire
   be able to illustrate
9.10 Lightning
   Car struck by lightning – BBC
   Answer 1-6 p.291
   Be able to draw a lighting diagram (as in
    class)

				
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posted:8/21/2011
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