Unit 8
Electricity and Magnetism
Page 9: Essential Question 1
What causes charged
objects to push and pull
on each other?
Page 8 - How do objects get an
electrical charge?
O Review: Parts of the Atom
O Electron: negative charge;
outside of the nucleus
O Proton:positive charge, in the
nucleus
O Neutron: no charge , in the
nucleus.
Page 8 - How do objects get an
electrical charge?
O Charged: An unequal number of protons and
electrons
O Neutral: An equal number of protons and
electrons
Page 10 - How do objects get an
electrical charge?
O Three Ways for objects to
become charged.
1. Friction
2. Conduction
3. Induction
Page 10 - How do objects get an
electrical charge?
O Charging by Friction
O When electrons are
rubbed off of one
object onto another.
Page 124 - How do objects get
an electrical charge?
O Start with 2 Neutral objects and end with 2
opposite charged objects.
Page 10 - How do objects get an
electrical charge?
O Charging by Conduction
O Electrons are transferred
from one object to
another by contact.
Page 10 - How do objects get an
electrical charge?
O Start with 1 Neutral and 1 Charged
and end with 2 like charges.
Page 10 - How do objects get an
electrical charge?
O Charging by Induction
O When the charges in
an uncharged object
are rearranged without
direct contact.
Page 10 - How do objects get an
electrical charge?
O When the charged object leaves,
the induced charge goes away.
Page 10 - How do objects get an
electrical charge
O The Law of Conservation of Charge
O Electrons cannot be created or
destroyed, they simply move from
one object to another.
Page 10- How do objects get an
electrical charge?
O Electroscope: Tool used to detect electrical
charge.
Page 10 - How do objects get an
electrical charge?
Page 10- How do objects get an
electrical charge?
O Electrical Force: When
Electrons and Protons push
or pull on each other.
Page 127- How do objects get
an electrical charge?
O The Law of Electrical Charges
O Opposites charges attract and
like charges repel.
Page 10- How do objects get an
electrical charge?
Page 12- How do objects get an
electrical charge?
O Static Electricity: When
charges build up on an
object.
Page 12- How do objects get an
electrical charge?
O Electrical Discharge: loss of static electricity
as charges move off the object.
Page 12- How do objects get an electrical charge?
Page 14 – Electrical Materials
How do we try to control
electrical energy?
Page 14– How do we try to
control Electrical Energy?
O We try to control the movement
of electrons by using conductors,
insulators and semiconductors.
Page 14– How do we try to
control Electrical Energy?
O Electrical Conductor: Materials
that electrons move through
easily.
O Examples: ALL METALS.
Page 14– How do we try to
control Electrical Energy??
O Electrical Insulators: Materials
that electrons have a difficult
time moving through.
O Examples: ALL NONMETALS
Page 14– How do we try to
control Electrical Energy?
O Electrical Semiconductors: Allows
electrons to flow only one direction
through the material.
O Examples: METALLOIDS ( Silicon)
Page 14– How do we try to
control Electrical Energy?
Page 16 – Parts of Electrical
Circuits
O Current: the rate at which charge
passes through a conductor.
O More current means more charge.
Page 16: Parts of Electrical
circuits
O Alternating Current (AC)
O Current that travels back and
forth through a wire.
O Current in our Homes.
Page 16
O Direct Current
O Current that only flows one way through a
wire
O Current that comes from a battery or
solar panel.
Page 16
O Voltage: The amount of energy
released as a charge moves from
one place to another.
O How hard the electrons are pushed
through a conductor.
Page 16
O Resistance: the opposition to the
flow of electrical charge.
O Insulators have a high resistance and
conductors have a low resistance.
Page 14
O The size of the conductor affects
the resistance.
1. A wider wire (bigger diameter)
has less resistance.
2. A shorter wire has less resistance.
Page 14
O Temperature affects resistance
O Higher temperatures make
more resistance.
Page 16 – OHM’S LAW
Ohm’s Law
V  IR
Symbol
Name
Unit
V
Voltage
Volts (V)
I
Current
Amperes (A)
R
Resistance
Ohms (  )
Page 16 – Ohm’s Law Example
Problems
O How much current flows from an electrical
eel if it can generate a voltage of 600 V
through water with a resistance of 100 Ω?
Page 14 – Ohm’s Law Example
Problems
O What is the resistance of the human skin if
a 9.0 V battery causes 0.02 amps of current
to flow through the skin?
Page 20
Electric Circuit Basics
OHow do electrical
circuits work?
Page 20 – How do electrical
circuits work?
O Water Analogy
Page 20 – How do electrical
circuits work?
O Parts of a circuit
O Power Supply
O Wire/Conductor
O Load/Resistance
Page 20 – How do electrical
circuits work?
O Open and Closed
Circuit
O A circuit must have a
complete path (closed
circuit) for electrons to
flow.
Page 20 – How do electrical
circuits work?
O Other Electrical Devices
O Switch: Opens and Closes a circuit
O Solar Cells: Creates DC current
when light hits it.
Page 20 – How do electrical
circuits work?
O Series Circuit: All parts are
connect in a single loop.
Page 20 – How do electrical
circuits work?
O Parallel Circuit: Parts are connected
in separate branches of the circuit.
Page 22 – How do electrical
circuits work?
O Diode: A semiconductor that only allows
current to flow one way through the circuit.
O LED (light emitting diode): Gives off visible or
Infrared light when electricity flows through
it.
Page 24- What is a Magnet?
What are properties of
magnets?
Page 24– What are properties
of Magnets?
O What to find in the reading
O What is a magnetic field?
O What are the ends of a magnet called and
O
O
O
O
O
how do they interact with each other?
Where is a magnetic field the strongest?
How does a piece of iron become a magnet?
What happens when a magnet breaks?
How is an electromagnet made?
How do we use magnets to make electricity?
Page 24 – What are properties of
magnets?
O Magnet: any material that
attracts iron or materials
containing iron.
Page 24 – What are properties of
magnets?
O Magnets have poles.
O North Pole and South Pole
Page 24 – What are properties
of magnets?
O Opposite poles attract and
like poles repel.
Page 24– What are properties of
magnets?
O Magnets create a Magnetic
Fields that are strongest at the
poles.
Page 24 – What are properties of
magnets?
O Breaking a Magnet in half creates two
new magnet.
Page 26 - Essential Question 5
How to make temproray
magnets?
Page 26 – How do we make
magnets?
O A wire carrying a
current makes a
magnetic field
around the wire.
Page 26 – How do we make
magnets?
O Solenoid: A coil of wire
that produces a
concentrated magnetic
field.
Page 26 – How do we make
magnets?
O An iron core becomes
an electromagnet
when it is placed
inside a solenoid.
Page 26 – How do we make
magnets?
O Electromagnet: a magnet made by
wrapping a wire around an iron core
and hooking the wire up to a power
source.
Page 26 – How do we make
magnets?
O Electromagnets are temporary
magnet that stops when the
current stops.
Page 26 – How do we make
magnets?
O How to make a stronger Electromagnet
More turns (loops) of wire
2. More current
3. More Iron Core
1.
Page 28?
O Electrical Generator: Converts
mechanical energy to electrical
energy.
Page 24
O Wire spins inside a magnetic field!
Page 24
O What is the energy conversion for a coal
burning power plant?
Page 30
O Electrical Motor: Converts
electrical energy to mechanical
energy.
O Opposite of a generator, it is a
generator that is reversed.
Page 30
Current in the wire causes the
wire to spin in the magnetic
field.
Page 30
O Where can you find examples of electric
motors?