How Soil Was Formed
About the How Soil Was Formed Lesson
This is an introductory lesson about the formation of the earth and the development of soil and plant life through the process of weathering.
• to explain and discuss the process of terrestrial cooling and hardening;
• to explain and discuss the process of soil creation and plant life on earth;
• to define and explain the meaning of a symbiotic relationship.
Scientists believe that many millions of years ago the earth was a mass of molten rock. Over a few more million years, the earth slowly began to cool and harden. The jagged surface, with peaks and valleys, hardened into a rock crust several miles thick. Then the earth?s surface went through many more changes.
Earthquakes shook and toppled high peaks. Volcanoes pierced the surface. They spewed out lava and filled the sky with ash. The changing temperature caused rocks to crack and split apart. The wind battered the surface blowing smaller rock particles and dust against the rocks. All of this activity was a form of ?weathering.?
The atmosphere above the surface was not only very hot, but it was filled with smoke, ash, and dust from all the activity going on below. The sun could not shine through this thick cloud. Any rain that fell quickly evaporated before it could reach the rock.