TITLE:  LAYERS OF THE EARTH  

AUTHOR:  Laura Wilson, Hammon, OK  
 
GRADE LEVEL/SUBJECT:  2-6, earth science

OVERVIEW:  This is an introductory lesson that can be expanded
into the following areas: Geology, volcanos, earthquakes, and
archaeology.  It introduces the layers of the earth and the basic
composition and distance of each.

PURPOSE:  The purpose of the lesson is to introduce geology in
its simplest form and how a rock is formed.  It can also be used
the sciences listed above with a few miner changes.

OBJECTIVES:  As a result of these activities the student will:
  1.  Identify the layers of the earth and the approximate
distances of each. 
      A. Crust  6-40 miles.
      B. Mantle 1,800 miles.
      C. Outer core 1,375 miles.
      D. Inner core 1,750 miles.
  2.  Identify and list the sciences that study the earth's
layers and the importance of the information gathered and how it is used.
  3.  Identify the basic composition of each layer.
  4.  Be able to web any subject in groups or individually. 

RESOURCES/MATERIALS:
Teacher materials:  Blue, brown, yellow, black, and white
construction paper marked with the appropriate diameter circle. An
apple, knife, and "The Magic School Bus inside the earth".
Student materials:  Scissors, glue, a black and white crayon to
label with and a box of crayons to color the project.

ACTIVITIES AND PROCEDURES:
  1.  Introduce the layers of the earth using an apple.  Cut the
apple in half across the core.  Explain that the skin represents
the crust, the heart represents the mantle, the seed coat represents
the outer core, and the seed represents the inner core.
  2.  Read "The Magic School Bus inside the earth" by Joanna
Cole.  This explains the layers of the earth and the composition of each.
  3.  As a group web or brainstorm one or all of the sciences that
study the layers of the earth and the importance of each. This can
be general information or very specific.
  4.  Using construction paper have each student model the
layers of the earth.  Blue 8 1/2 " circle labeled 6-40 miles. 
The crust is made of many plates which "float" above
mantle.  The crust is thicker and lighter at the continents and
thinner and denser at the ocean floor.  Brown 7 " circle labeled
1,800 miles.  The mantle lies below the crust.  It is a thick layer
of solid rock.  Many scientists believe that the mantle transfers
heat from the core to the surface.
Yellow 6" circle labeled 1,375 miles.  The outer core is made of
melted iron and nickel.  It is much denser than the rock layers above
it.  The temperature of the outer core can range form 4000 to 9000 F.
Black 3" diameter circle labeled 1,750 miles.  The inner core is made
of solid iron and nickel.  These materials sank to the center of the
earth while it was still in a molten form.     
  Use white construction paper for the background and label each
circle at the top as it is glued to the background.  Have each
student decorate their projects as they now understand the earth. 
Layer information gathered form "Mailbox Magazine" June/July, 1991. 

  1.  Review the importance of studying layers and begin in depth
units on any of the following areas: Geology, Volcanos, Earthquakes,
and archaeology.
  2.  Have the students share their projects and explain the
differences.
  3.  Have the students web as a group or individually one area of
science that uses the layers of the earth that interested them most.