Download Conserving Resources

Conserving Resources
8th Grade Science Book
Chapter 14
Resources
• Natural
resources –
parts of the
environment
that are useful
or necessary for
living organisms
to survive.
Natural Resources
• A natural
resource that
is constantly
recycled or
replaced is a
renewable
resource.
Natural Resources
• Natural resources
are used up more
quickly than can be
replaced are called
nonrenewable
resources; for
example petroleum
takes hundreds of
millions of years to
form.
Fossil Fuels
• Fossil fuels such as coal, oil,
and natural gas are
nonrenewable energy resources
that form in Earth’s crust over
very long periods of time.
Alternative Energy
• Alternative energy sources can
be used to help conserve fossil
fuels.
• Hydroelectric power – energy from
falling water used to generate
electricity.
Alternative Energy
• Wind – wind turns the blades of a
turbine, which powers an electric
generator.
Alternative Energy
Nuclear Power – the fission of
uranium atoms generates
nuclear energy that is used to
produce electricity.
Alternative Energy
• Geothermal power plants use
geothermal energy from the
heat in Earth’s crust to generate
electricity.
Alternative Energy
• Solar energy can be captured in
photovoltaic cells, which turn
sunlight into electric current, or
in materials that retain heat.
Section Two
Pollution
Pollution
• A pollutant is a
substance that
contaminates
the air, land, or
water.
Air Pollution
• Air pollution
sources include
soot, smoke,
ash, and gases
such as carbon
dioxide, carbon
monoxide,
nitrogen oxides,
and sulfur
oxides.
Pollution
• Smog is
created
when
sunlight
reacts with
pollutants.
Pollution
• Acid precipitation
results from air
pollutants reacting
with water in the
atmosphere.
• Acid rain can kill
plants and animals.
• Reducing the use of
high sulfur coal and
lowering pollutants
from vehicle
exhaust can help
prevent acid rain.
Pollution
• The atmosphere traps heat through
the greenhouse effect; increased
carbon dioxide trapped in the
atmosphere may cause global
warming.
• Ozone depletion, the thinning of the
ozone caused by
chlorofluorocarbons (CFCs) and can
result in increased UV radiation
reaching Earth’s surface.
Pollution
• Insulation can
trap indoor air
pollutants such
as carbon
monoxide or
radon.
Water Pollution
• Water is
polluted when
air or land
pollutants
enter the
rivers, lakes,
or oceans.
Water Pollution
• Surface water
pollutants include
chemical pesticides,
raw sewage, and
fertilizer.
• Rivers and streams
dump pollutants into
the ocean; oil spills are
also a source of
seawater pollution.
• Groundwater can
become polluted as it
seeps through particles
of rock and soil or
collects in underground
pools called aquifers.
Erosion
• Erosion is the
movement of soil
from one place to
another; it causes
the loss of fertile
topsoil.
• Soil can be polluted
by solid wastes in
landfills or by
hazardous waste
such as dangerous
chemicals or
radioactive
materials.