Name: ________________________
Hour: __________
Hydroelectric Power
Hoover Dam, with its towering walls represents an idea even
bigger than itself. The dam symbolizes human ingenuity and our
ability to transform the environment and make even a harsh desert
habitable. By generating power, controlling downstream flooding,
and storing water for irrigation and city use, Hoover Dam fueled
the growth of the American Southwest.
Lake Mead, the reservoir Hoover Dam creates by holding back the
Colorado River, holds 35 billion cubic meters of water, which
generates tremendous force. The water pressure near the base of
the dam is close to 220,000 kilograms per square meter. The dam
resists this force -- otherwise it wouldn't remain standing. It also
harnesses this force and uses it to generate electricity.
Hoover Dam doesn't stand as an impenetrable barrier to the water
in the reservoir. It constantly releases water at a rate of about
15,000 cubic meters each second, which is more than half the
water in an Olympic-sized swimming pool. Inside the dam are 17
hydroelectric generators, each attached to a huge fan-like structure
called a turbine. As water is released from the reservoir, it flows
through pipes in the dam and past the turbine blades, causing the
turbines to spin and the generators to which they're attached to
turn.
Generators, including those in Hoover Dam, produce electricity
through a process called electromagnetic induction. When a loop
of wire moves through a magnetic field, or vice versa, an electrical
current is produced. As the turbines in Hoover Dam spin, they
cause electromagnets to turn inside stationary wire loops, inducing
current in those loops.
Hoover Dam generates more than 4 billion kilowatt-hours of
electricity each year, enough to serve 1.3 million people. Still, this
efficient and seemingly cheap source of power is not without its
costs. Dams create impenetrable barriers to spawning fish, and
large reservoirs destroy important and uncommon river and canyon
wildlife habitat. They can also disrupt human habitat and submerge
land that has been traditionally available for other uses. For these
reasons, environmental groups decry the existence of dams like
Hoover Dam and oppose the construction of additional ones.
1. What is hydroelectric power?
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2. What is the role of the turbine in generating electricity?
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3. What are the pros and cons of constructing large dams?
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4. How has the Colorado River been affected by the
construction of the Hoover Dam?
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5. Many types of technology require some form of electricity to
run. What things do you use each day that require electricity?
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