Transcript File

Chapter 17.1
Solar Energy
Solar energy
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It is energy from the sun and used as fuel by
virtually every organism.
It drives both wind energy and the water cycle.
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The upside to solar energy is it is free, clean,
and non-polluting
The negatives are that the equipment may cost
more than the benefits and that light is in limited
supply.
Passive Solar Energy
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The sun's energy is collected, stored and
distributed naturally in an enclosed dwelling.
This can be seen in modern day greenhouses
and some homes.
Active Solar Energy
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There is many more parts to an active solar
energy system.
It uses devices to collect, store, and circulate
heat produced from solar energy.
Photovoltaic Cell
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The only solar energy device that produces
electricity directly.
It uses thin wafers of semiconductor material to
produce electricity directly from solar energy.
Ex.: satellites, calculators
No moving parts or pollutants.
Chapter 17.2
Hydroelectric Energy
Hydroelectric Power
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Electricity that is produced from the energy of
moving water.
It is a non-polluting and less expensive than
fossil fuels and nuclear power.
History of Hydroelectric Power
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For hundred of years water wheels were used
to grind grain.
Water turbines were used in the 1800's to make
electricity.
Modern Hydroelectric Power
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Today huge dams are used to produce up to
twenty percent of the world's energy.
Water is directed into at blades that turn coils of
wire through a magnetic field producing
electricity.
They also provide flood control, ship navigation,
and recreation.
Negatives
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By altering the depth
of bodies of water the
it effects the natural
plant life of streams.
It can also erode the
shoreline.
Fish especially
salmon are caught in
the turbines or their
migrating paths are
disrupted,
temperature changes
also effect the fish.
Tidal Energy
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The tides produce large amounts of energy.
The same concept of turbines can be used for
tidal energy.
This unfortunately also effects benthic and
wetland ecosystems.
17.3 Wind Energy
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Aerogenerators are
windmills used to
generate electricity.
Some still use
windmills to grind
grain and pump
water.
Wind power is free
clean and nonpolluting.
Today's Windmills
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The traditional looks
like the propeller of an
airplane and can
produce the most
amount of electricity.
The Darrieus rotor
looks like an upside
down eggbeater and
turns on a vertical
axis. It can produce
electricity at a much
lower speed.
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The Darrieus rotor looks like an upside down
eggbeater and turns on a vertical axis. It can
produce electricity at a much lower speed.
Wind Farms
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These sites contain many windmills and are
located in open areas where windy conditions
are favorable.
Problems
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Bird injuries
Equipment is expensive
Takes a lot of land
Disturbs cell phone and TV reception
17.4 Geothermal Energy
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The sun is the main
source of energy for
Earth, but the earth
creates a lot of energy
itself.
Deep in the Earth’s
core the decay from
radioactive elements
produces energy.
Geothermal Energy
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Geothermal energy is
heat energy generated at
the Earth’s core.
The temperature rises
between 30 to 45
degrees c with every
kilometer down. It has to
level off somewhere and
the center is probably
between 3 and 5
thousand.
Methods of Extracting
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In areas where bedrock is heated by magma
known as hot rock zones, explosives are used to
break the rock. Then water is poured onto the
hot rocks. This produces steam that turns
turbines.
Negatives
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Most places are not
suited to have a
geothermal plant. This
is due to heavy
pollution in some
areas that gives off
hydrogen sulfide gas
and toxins corrode the
pipes.
Nuclear Fusion
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This occurs when two
atomic nuclei fuse
together to become
one larger nucleus.
This is the source of
the sun’s energy.
Technology is not
advanced enough to
harness this energy.