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About "Ask A Scientist!"

On September 17th, 1998 the Ithaca Journal ran its first "Ask A Scientist!" article in which Professor Neil Ashcroft , who was then the director of CCMR, answered the question "What is Jupiter made of?" Since then, we have received over 1,000 questions from students and adults from all over the world. Select questions are answered weekly and published in the Ithaca Journal and on our web site. "Ask A Scientist!" reaches more than 21,000 Central New York residents through the Ithaca Journal and countless others around the world throught the "Ask a Scientist!" web site.

Across disciplines and across the state, from Nobel Prize winning scientist David Lee to notable science education advocate Bill Nye, researchers and scientists have been called on to respond to these questions. For more than seven years, kids - and a few adults - have been submitting their queries to find out the answer to life's everyday questions.

Previous Week's Question Published: 11 July, 2001 Next Week's Question
Misconceptions surround desert terrain, vegetation
Question
How come deserts have sand instead of dirt and soil?

Question
Many people think of deserts as blowing sand dunes because of how they are often depicted on TV and in movies. In actuality, many desert regions are rocky and gravelly and have beautiful, but sparse, desert vegetation. Think of the beautiful saguaro cactus (with the waving arms) in Arizona and Northern Mexico!

For a soil scientist, a desert still has "soil," although it is different from the ones around here. You don't see the dark and fine soil material in deserts due to a difference in climate. Soils in New York were formed from material that was deposited by glaciers. After they disappeared, the land was covered with lush forests. Dead leaves, branches and roots were mixed in by soil animals like moles, worms, and insects, and broken down by microbes. So, our soils became dark and rich and good for growing crops.

In the deserts, soils were primarily formed from the physical weathering (breaking apart) of rocks due to large temperature fluctuations between day and night, freezing and thawing, and the processes of erosion and sedimentation. The dry desert climate supports little vegetation and soil life. Therefore, organic matter levels in desert soils are very low and chemical weathering that dissolves rock and creates fine clay minerals does not occur. Also, the barren soil allows the fine minerals to be blown away easily. So what is left is sandy, gravelly, or rocky material (but it is still "soil"). For the same reason, our Moon and the planet Mars have those types of land surfaces. It is the fact that our soils are so alive that makes them special. Oh yes, one more thing: We don't really use the term "dirt", unless we are referring to the stuff on our sleeves or boots.