# 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

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
   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,

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)

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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