Comment: 19:19 - 20:19 (01:00)
Source: Annenberg/CPB Resources - Earth Revealed 26. Living With Earth, Part II
Keywords: "fossil fuel", hydropower, dam, power, "wind power", "solar power", energy, "photo-voltaic cell", "external heat engine"
Our transcription: One alternative to fossil fuels, which has been in use for some time, is hydropower.
Water rushing through passageways in dams spins enormous turbines, which generate electricity.
A more recent development is the "wind farm," vast numbers of air turbines stretched across hillsides convert the force of the wind into electric power.
Light from the Sun is yet another alternative source of energy.
With the use of photo-voltaic cells, sunlight generates electricity.
It is also used to heat water and buildings.
Each of these alternatives to fossil fuels is driven by Earth's external heat engine -- the energy of the Sun transformed into wind, light, or running water.
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