Transcript UNIT FIVE: Electricity and Magnetism  Chapter 16 Electricity  Chapter 17 Magnetism.

UNIT FIVE: Electricity and Magnetism
 Chapter 16 Electricity
 Chapter 17 Magnetism
Chapter Seventeen: Magnetism
 17.1 Properties of Magnets
 17.2 Electromagnets
 17.3 Electric Motors and Generators
 17.4 Generating Electricity
Chapter 17.4 Learning Goals
 Review the meaning of mechanical power
and liken it to electrical power.
 Compare and contrast renewable and
nonrenewable sources of electrical
energy.
 Discuss methods of electrical energy
conservation.
17.4 Generating Electricity
 Electricity is made in a power plant.
 Most power plants burn fossil fuels
(natural resources like coal, oil, or
natural gas) to produce heat.
17.4 Generating Electricity
 Next, this heat is used to boil water.
 The steam from the boiling water turns a
turbine.
 The turbine turns a generator which produces
electricity.
17.4 Electricity from fossil fuels
 A nonrenewable resource is not replaced
as it is used.
 Because it takes so long for these
resources to form, someday we will not
have enough fossil fuels to produce the
electricity we need.
 The three major fossil fuels are coal, oil,
and natural gas.
The United States gets about 19% of its electricity
production from nuclear power plants.
17.4 Electricity from nuclear energy
 The main advantage of
using nuclear energy to
produce electricity is
that it doesn’t pollute
the air like fossil fuel
power plants do.
17.4 Electricity from nuclear energy
 Storage of nuclear waste has
always been a major
disadvantage of nuclear power
plants.
 Uranium fuel from the reactor
stays dangerously radioactive
for a long time.
17.4 Electricity from renewable
resources
 A renewable resource can be replaced
naturally in a relatively short period of
time.
 The Sun and wind are
renewable resources
that can be used as
energy sources.
17.4 Electricity from renewable
resources
 It is also possible to use:



moving water (hydroelectric)
hot spots near Earth’s surface (geothermal)
fuels made from once-living things like
wood or corn (called biomass) or
 tides to produce electricity.
17.4 Hydroelectric power
 A hydroelectric (or
hydropower) plant
uses energy from
falling water to
generate electricity.
17.4 Geothermal and biomass
 Geothermal power plants use Earth’s
internal heat energy, in the form of water
or steam, to produce electricity.
 A geothermal heat pump system takes
advantage of the relatively constant
temperature of Earth’s shallow ground.
17.4 Geothermal and biomass
 Biomass is organic material from plants
or animals.
 In waste-to-energy plants, renewable
solid waste is burned to produce
electricity, which also creates some air
pollution.
17.4 Wind and solar energy
 California was the
first U.S. state to
build large wind
farms.
 Wind farms can
disturb natural
habitats, and can
perhaps scar a large
area of scenery.
17.4 Wind and solar energy
 The Sun’s energy
is often called
solar energy.
 A solar cell (also
known as a
photovoltaic cell)
can convert solar
energy to
electricity.
17.4 Electrical power
 Electrical power is
measured in watts, just
like mechanical power.
 Electrical power is the
rate at which electrical
energy is changed into
other forms of energy
such as heat, sound, or
light.
17.4 Electrical power
 Utility companies charge customers for the
number of kilowatt-hours (kWh) used each
month.
 A kilowatt-hour is a unit of energy.
 The number of kilowatt-hours used equals the
number of kilowatts multiplied by the number of
hours the appliance was turned on.
17.4 Electrical power
 There are many
simple things you
can do to use less
electricity.
 When added up,
these simple things
can mean many
dollars of savings
each month.
Under the Sea
 Have you ever wondered what
it would be like to take a “walk”
on the seafloor? Engineer Jim
Varnum gets to go “down
under” regularly, because he is
a pilot of an extremely complex
robot called Jason II. This
robot dives deep into the ocean
and is used to take pictures
and collect data from the
seafloor.