Comment: 01:54 - 03:06 (01:12)
Source: Annenberg/CPB Resources - Earth Revealed - 22. Wind, Dust and Deserts
Keywords: "Art Montana", "Tropic of Cancer", "Tropic of Capricorn", desert, "Earth's surface", vegetation, Antarctica, precipitation, polar, "South Pole", "Point Barrow", Alaska, rainfall, soil, water, pond, lake, "Mojave Desert", California, "giant yucca", "Joshua tree"
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Our transcription: Located primarily along the Tropics of Cancer and Capricorn, deserts cover almost one quarter of the Earth's surface.
Most of us have a very limited, somewhat stereotypical picture in mind when we think of what a desert looks like, but the fact is that deserts can take many, sometimes unexpected shapes and forms.
If you asked most people, they would probably say that the desert is a dry area with no vegetation.
But this isn't a very good definition for several reasons.
One, there are many dry areas with no vegetation on the surface of the Earth that you wouldn't think of as deserts; Antarctica, as an example.
There's almost zero precipitation at the South Pole.
We can look at Point Barrow, Alaska, which receives only four or five inches of rain a year and has very little vegetation; yet the soil there is water sodden, and there are little ponds and lakes, and it's hardly what you would think of as a desert.
On the other hand, some deserts have a great deal of vegetation.
The Mojave Desert of eastern California has vast stands of the giant yuccas, the Joshua trees.
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Geology School Keywords
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