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Describe fossil fuels and explain why coal is a fossil
Summarize the processes of nuclear fission and
nuclear fusion.
Explain how nuclear fission generates electricity
Explain how geothermal energy may be used as a
substitute for fossil fuels
Compare passive and active methods of harnessing
energy from the sun
Explain how water and wind can be harnessed to
generate electiricty
Fossil Fuels
Fossil fuel: a
nonrenewable resource
formed from the remains
of organisms
• Oil
• Coal
• Natural gas
resources: resources
which form at a rate
much slower than the
rate at which they are
Much of the energy
humans use every day
comes from the burning
fossil fuels.
Problems with Fossil Fuels
Impurities in fossil
fuels are a major
source of pollution
Burning fossil fuels
produce large
amounts of CO2,
which contributes to
global warming
Coal Energy
Coal is the most
abundant fossil fuel in the
world. 2/3 of all coal
deposits are in the US,
Russia, and China.
Coal is formed during
carbonization, which
occurs when partially
decomposed plant
material is buried in
swamp mud and
becomes peat.
As bacteria consume
some of the peat,
methane and CO2 are
released, and the
contents gradually
change until mainly
carbon remains.
Alternative Energy: Nuclear
Nuclear fission: process
by which the nucleus of an
atom splits into two or
more fragments
• releases neutrons &
Newly released neutrons
strike and split nearby
nuclei, which causes the
release of more neutrons
and energy, initiating a
chain reaction
Uncontrolled fission
reactions escalate quickly
and result in a nuclear
Controlled reactions
produce heat which can be
used to generate electricity
How Fission Generates Electricity
Nuclear reactor:
specialized area where
controlled nuclear fission
is carried out
Chain reaction from
nuclear fission causes fuel
rods to become very hot.
Water is pumped around
the rods to absorb heat
The water is then pumped
into an area where it
becomes steam and turns
turbines which provide
power for electric
A third water area carries
away excess heat and
releases it into the
Advantages/Disadvantages of
Nuclear Fission
• Nuclear power plants
do not burn fossil fuels
or produce air
• However, they
produce radioactive
material which decay
slowly, so they must
be stored for
thousands of years
• The material emits
doses of radiation
which may be harmful
if not stored properly
Yucca Mountain
Geothermal Energy
• Renewable
resource: a natural
resource which can be
replaced at the same
rate at which it is
• Geothermal energy:
energy produced by
heat of the Earth
• The steam from hot
water passing near
magma produces a
large amount of energy
• Scientists drill wells to
reach the hot water
• The hot water drives
turbines, which
generate electricity.
Solar Energy
• Solar energy: energy
from the sun
• Solar energy can be
converted to heat
• In a passive system,
sunlight enters the
house and warms it
• An active system
includes solar
collectors, which
convert solar energy
into electricity.
Energy from Moving Water
Hydroelectric energy:
electrical energy produced
by the flow of water
Energy can be harnessed
from the running water of
rivers, streams, or ocean
11% of the electricity in the
US is derived from
hydroelectric power
At a hydroelectric plant,
massive dams hold back
running water and channel
the water through water
spins turbines, which turn
generators and produce
Energy from Biomass
Biomass: plant
material, manure, or any
other organic matter
used as an energy
• major source of
energy in many
developing countries
Bacteria which
decompose organic
matter produce gases or
liquids, which can be
More than half of all
trees that are cut down
are used as fuel for
heating or cooking.
Energy from Wind
Wind energy may be
used to produce
electricity in locations
with constant wind.
Wind farms: hundreds
of giant turbines which
produce enough energy
to meet the electric
needs of entire
Not practical
everywhere because the
wind does not always
Preserving the Environment
preservation of natural
Recycling: recovering
valuable or useful
materials from waste or
• requires energy, but uses less
than manufacturing new
Fossil fuels can be
conserved by reducing the
amount of energy used
every day
Reducing the amount of
driving, using insulation for
a house, energy-efficient
appliances, all help
conserve energy