ELECTRICITY

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ELECTRICITY
 
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Notes vs Discussion

• In this chapter we will write out our class notes
• Your are to write any information that is in RED
• Anything in black does not need to be copied by
  you.
• Your outline will only consist of practice
  worksheets and lab activities for this chapter.

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• Atom ATOMIC
• BOMB
• Nucleus NUCLEAR
• POWER
• Electron Electricity

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The ATOM
The atom is made of 3 basic parts 1.
Protons 2. Neutrons 3. Electrons The nucleus
contains both protons and neutrons together.
Electrons
(Negatively charged)
Nucleus
Neutrons
(Neutral charge)
Protons
(Positively charged)
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HYDROGEN
(Proton)
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Nucleus
Protons Neutrons
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NUCLEUS ELECTRONS ATOM
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PROTONS ELECTRONS
Neutral
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PROTONS gt ELECTRONS
Missing Electron
Positive
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PROTONS lt ELECTRONS
Negative
Extra Electron
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Electric charge

• 3 Types of electrical charge
• Positive - more protons than electrons
• Negative - more electrons than protons
• Neutral - same amount of protons and electrons

More about atoms!!!!!!
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Atoms become charged when they gain or lose
electrons

• Gain electrons - become negatively charged
• Lose electrons become positively charged
• Protons do not move from atom to atom.
• The natural state of any atom is to be neutral.
• Charged atoms in a liquid are called IONS

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Same charges repel
Law of Electrical Charges
Different charges attract
Demo
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Another way to show attract and repel
The act of repelling or attracting occurs because
of
Electric Forces
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Why does a balloon stick to the wall?

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Why does your hair do this??

Each hair becomes negatively charge and therefore
REPELS each other.
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Electric Discharge-The rapid movement of excess
charge from one place to another.

• 2 Forms of Discharge
• Sparks (Small discharge)
• Lightning bolts (Large discharge million volts)

Flash Gallery Lightning form
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Lightning- a large electrical discharge between
the atmosphere and ground.

• 3 ways lightning can strike
• Cloud to ground
• Ground to cloud
• Cloud to cloud

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Formation of Lightning

• Collection of negative charges in cloud.
• Ground becomes positive.
• Stepped leader forms in between and makes
  connection with ground
• Invisible discharge takes place
• Return stroke that we see.
• 4 6 return strokes can take place during one
  strike.

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Positively
charged at the top
___ ___Negatively charged towards bottom ___ ___
___ ___ ___ ___ ___ __ __ __ __ __ __ __
Stepped Leader forms first
The lightning we see return stroke
Positively charged
ground
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Invisible Channel is very jagged and
unpredictable.
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Types of Lightning

• Ribbon lightning

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Ball Lightning
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Sheet Lightning
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Bead Lightning
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Red Sprites
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Blue jets
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Lightning and Thunder5 miles for every second
counted
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Electric Circuits

• Circuit A closed conducting pathway for
  electrons to flow through.

The flow of electrons is called
Electric current
Electric current is a lot like the flow of water
through pipes
Simulation
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Simple Circuits

• 3 parts to a simple Circuit
• 1. Source of Electricity
• battery
• 2. Conductor
• wire
• 3. Load
• Light bulb or motor
• What electrons do work on

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Draw in your notes!!!!!
Source

_
Conductor
Load
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Batteries and BulbsStudent Challenge!!!!!!
Can you and your partner work together to make
the light bulb light up!!!! Use only the battery,
bulb (with no socket, and a piece of wire. There
are ten different combinations. Try to figure out
all ten. You must make a drawing of how you
arrange the items to make the bulb light using
the symbols below. Good Luck!!!
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Clue 1
Touch here
Touch here
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Clue 2
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Clue 3
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Conductors Materials that allow electrons to
flow easily. We use these materials in
electrical circuits.
silver copper gold aluminum iron steel
brass bronze mercury graphite dirty water
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Insulators Insulators don't allow electrons to
flow easily. We use these materials to protect
ourselves.
glass rubber asphalt fiberglass cotton paper
wood plastic air
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Argon gas
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Tungsten Filament is double coiled to allow for
up to 30 feet of wire give off the glow.
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Source of Electricity (Battery)

• Supplies electrical potential energy to a
  circuit.
• Sets the voltage of the circuit.

2 types of batteries
Dry Cell
Wet Cell
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Wet Cell versus Dry Cell

• Used in automobiles
• High voltage (12v)
• Short life
• Needs recharged often
• Liquid electrolyte (salt or acid)

• Used in small electronic equip.
• Low voltage ( 1.5v)
• Long life
• No recharging
• Manganese paste electrolyte

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Electrical Symbols

• Source
• Light bulb
• Motor
• Switch on
• Switch off

• Voltmeter
• Ammeter
• Resistance
• Fuse

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Series Circuits a circuit that has only a
single path (one loop) for current to flow
through all of its parts.
Bulbs in Series
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Batteries in Series
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Parallel Circuits - requires more than one path
for current flow in order to reach all of the
circuit parts.
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Batteries in Parallel
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Fuses and Circuit Breakers
Devices that open a circuit due to overload.
(drawing to much current) prevents damage
or potential fire
Fuses open a circuit when a narrow filament
melts. Not reusable.
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New Fuse
Blown Fuse
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Breakers a switch that automatically opens a
circuit when overload occurs. Reusable
Switch can be opened 3 different ways. 1. heat
from circuit causes bimetallic strip to separate
2 metals. 2. electromagnet breaks circuit 3.
small explosion
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Calculating Electrical Cost
Step 1 Calculate wattage (volts X amps)
220 volts X 3 amps 660 watts
Step 2 Convert watts to Kilowatts (X .001) or
divide by 1000
660 X .001 .66 kilowatts
Step 3 Multiply kilowatts by the amount of time
used. All numbers must be in hours.
.66 kilowatts X 3 hours 1.98 Kilowatt - hours
Step 4 Multiply Kilowatt hours by the rate or
price (around 0.10)
1.98 X .10 0.19