WEBVTT

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Joan Cartan-Hansen, Host: More
than seven percent of America's

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electricity comes from
hydroelectric dams.

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Dams create electricity using
stored water.

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Dams store water from rivers and
spring melt into reservoirs.

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Dam managers then allow water to
flow through a long pipe called

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a penstock.
From the top of the dam to the

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bottom.
The falling water spins blades

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in turbines.
Those spinning blades are

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connected to a generator.
Those generators use magnets and

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copper coils to create
electricity which is sent out on

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power lines.
Some rivers also have specially

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designed turbines to capture the
power of moving water to create

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electricity.
But dams and turbines do change

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the course of rivers.
And that can be deadly for fish

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like salmon that need a free
flow to migrate downstream.

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Hydroelectric power is
considered a green source of

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energy because it doesn't
require the burning of fossil

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fuels.
Most dams in the United States

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don't generate electricity, but
scientists say they could be a

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potential new source of power.
For more information about dams,

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check out the science trek
website.

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You'll find it at science trek