4-9 The Whole Earth

The Whole Earth

  As you read this article about the earth, think of a peach with its skin, fruit, and seed.  The layers of the earth are called the crust, the mantle, and the core.

  The earth's thin crust, or outer layer, is mostly rock and varies in thickness from 3 to 34 miles.  Beneath the crust is the mantle, a layer of mostly solid rock.  The mantle is about 1,800 miles thick.  It is very, very hot-about 5,400 degrees Fahrenheit in some places.  The center of the earth is called the core.  It is about 2,200 miles thick, and is extremely hot-about 7,200 degrees Fahrenheit.   Scientists believe the core is made up of two parts, an inner and an outer core.  They believe the outer core is a liquid layer made of melted iron and nickel.  They inner core is made up of solid iron and nickel.  

  Scientists who study the earth are called geologists.  Geologists study and learn things about the earth by studying clues from geological activities.  Geological activities are earthquakes and volcanoes.