ELECTRICITY by shuifanglj

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									WHAT IS ELECTRICITY?
   •The movement of electrons




            AN ATOM
        ATOMIC PARTS
 Electron= negative, easily lost
 Proton = positive
 Neutron = no charge, neutral




                         .
                         eia.doe.gov
     Law of Charges
Opposite charges attract
       -        +
      O         O
   Like charges repel
        -        -
       O        O
            Types of Materials
   Conductors – materials that allow electrons to
    flow through (metals, copper wire, water)

   Insulators – materials that do not allow electrons
    to pass through (wood, glass, plastic, rubber)

   Grounding- it is the process of removing the
    excess charge of an object by transferring (by
    way of a conductor) the electrons to another
    object. A 'ground' is an infinite source or sink
    for charge.
      STATIC ELECTRICITY
 The build up of electrons on the surface of
  an object
 Separated charge
 Net charge


 Electrons jump
 Less orderly
 Cannot harness
            STATIC ENERGY




   Rubbing a balloon on a wool sweater
    creates charges on the surfaces
   The balloon attracts electrons from sweater
GAINING OF ELECTRONS

         - - -
               -
       O-
          - - -
    STATIC ELECTRICITY




Which law of charges is displayed?
Why does his hair stand on end?
            Why hair stands up
   Hair is full of electrons.

   Like charges repel causing the hair to
    stand on end

   The hair stands push away from each
    other
STATIC ELECTRICITY




        Alaska.net



  Why do we see a spark?
            Opposites attract
 The door knob is positively charged
 A person is negatively charged


   The electrons jump through the air in the
    path of least resistance creating a spark

   What is the crackling sound you hear
    when you take clothes out of a dryer?
                   Static cling
   In dry conditions materials cling to each other or
    are attracted to each other due to the law of
    opposites.
   Clothes attach to your body
   Clothes from the dryer have static cling due to
    the rubbing together. The materials in dryer
    sheets remove the cling.

Why isn’t static cling present in humid conditions?
            Water Conductor
   Water is a conductor, and so all the
    electrons are attracted to it.

   Water pulls away the extra electrons and
    removes the static force that is causing
    your clothes to cling together
          Static in Radio & TV’s
   Dust and water vapor
    in the atmosphere
    create static

   Sensitive tuners
           VAN DE GRAAFF
            GENERATOR




                        mos.org
Moving belt accumulates what?
•The electrons jump from the surface creating a spark
 BIG SPARKS - LIGHTNING
     The bolt heats the air to 15,000 - 60,000 degrees F




How do charges behave during a storm?
              Opposites attract

   Electrons travel from earth to positive
    atmosphere where the clouds pick up and store
    lost electrons

   Clouds become negatively charged as ice
    crystals inside the cloud rub against each other

   The earth or ground is more positively charged
    and the electrons jump from the clouds to the
    ground or from one cloud to another
         Thunder
   Thunder is hot air colliding
    with cool air

   A lightning strike can heat
    the air in a fraction of a
    second. When air is heated
    that quickly, it expands
    violently and then contracts,
    like an explosion that
    happens in the blink of an
    eye. It's that explosion of air
    that creates sound waves,
    which we hear and call
    thunder.
                 Lightning Rods
   The rod connects to a
    huge piece of copper or
    aluminum wire. The wire
    is connected to a
    conductive grid buried in
    the ground nearby.
   If lightning strikes, the
    system attempts to carry
    the harmful electrical
    current away from the
    structure and safely to
    ground without causing
    any heat damage.
      CURRENT ELECTRICITY
 The flow of electrons through a conductor
 Charge flow
 Electric current


 Electrons flow not jump
 More orderly
 Can harness


   Two kinds – AC or DC
                Alternating or Direct Current
             Electricity
      STATIC             CURRENT
                         DC or AC
Net charge          Charge flow
Separated charge    Electric current
Electrons jump      Electrons flow thru
Surface of object   conductor

Less orderly Cannot More orderly
harness             Can harness
           BATTERIES
      DC or Direct Current

   Electrons flow in one direction
         Stored Electricity
         Chemical energy




               All-Battery.com
ELECTRON SHELLS




      web.jjay.cuny.edu
              A Battery has…

   A CATHODE which tends to accept
    electrons to be more stable
   An ANODE which tends to give up
    electrons to be more stable
   An ELECTROLYTE PASTE which
    transfers most of the electrons back to
    the anode when a circuit is complete.
                 CIRCUIT
   A conductor which connects a pathway
    between the (+) and the anode (-)




    CATHODE          wikipedia.org
                                     ANODE
      Battery is a charge pump
   Charges in battery want to get together to
    balance out

   A potential difference makes them move

   The paste moves the charges it does not
    make them

   The electrons will flow from negative end
    to the positive end
WET CELL BATTERY




      /lemcellguard.com/battery
    DRY CELL BATTERY




                             wikipedia.org




What happens in a battery over time?
Transfer of chemical energy to
   electrical & heat energy




    Entropy – the system becomes
     disorderly and needs energy
                MERCURY BATTERY
                    wikipedia.org




wikipedia.org
POTATO BATTERY




     www.miniscience.com
               Car Battery


   are known as "constant voltage" devices




                         www.dodge.com
   CURRENT ELECTRICITY
 The flow of electrons or current through
  a circuit is constantly switching back
  and forth (ie. 60 times each second)
 When current flow is controlled it can
  be used to do useful work.
 Can be transformed into
 Mechanical, Heat,
 Radiant or Light Energy

                                  orkneypics.com
                     Volts
Voltage = Force of electrons
Voltage is potential difference of electrons in 2
  places
 Garden Hose
 Homes use 110v and dryer and stove uses 220v


Potential Difference – needed in order for an
  electrical field to flow thru a material
 changing magnetic field creates current
 current = charges are moving
                 Amps
Amperes - are used to measure this flow of
  electrons
 Amps = number of electrons to flow thru
  wire in a second
 6.25 x 1018 or 6,250,000,000,000,000,000
  electrons/second
DIFFERENT TYPES OF
      WIRING
         cosmology.berkeley.edu




SERIES
            PARALLEL


         •Christmas Tree Lights
PARALLEL AND SERIES

            PARALLEL:
           SAME POWER
           LONGER TIME


               SERIES:
             MORE POWER
              SAME TIME
Watts- measurement of electrical power
 Power =work/time or volts x current (amps)
  Clock 3 watts
  Hair Dryer 1000 watts
  Clothes Dryer 4000 watts


    Kilowatt = 1 thousand watts (homes)
    Megawatt = 1 million watts (power plant)
    Gigawatt = 1 billion watts (large power plant)
    Quad = 1 Quadrillion BTU’s
             USA 74 quads/yr
             San Francisco 1 quad/yr

 BTU= Measure of energy, Amount of heat that will raise
   the temperature of one pound of water one degree
   Fahrenheit
            Cost of electricity
   Energy = power x time

   1kWh = 10 100 watt light bulbs burning for
    1 hour

 Average family uses 1000kWh in 1 month
 Utility company charge .10/kWh =
            1000 x .10 = $100.00
 GALVANOMETER

A   device that detects the flow of
              electricity
                  Efficiency
   Due to 2nd law of thermodynamics
    Efficiency is not 100%

   For example if efficiency is 33% that
    means for every 3 parts of fuel 2 parts are
    waste or unusable, only 1 part is usable
             ELECTRICITY
    Static                       Current


   Sparks
 Door knob          DC                           AC
  Balloons        (Battery)                   (Generator)
  Lightning
Van de Graaff
                                     Water                     Wind


                                                     Steam

                     Burn Material
                    Biomass
                    Coal
                    Nat Gas
                    Petroleum
                                     Boil Water
                    Plasma Arc     Solar                     Ground
                                   Nuclear Fission
                                                        Geothermal

								
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