Geol 301 (Spring 2007)
Modeling the Structure of the Earth
Part 1: Foldables – Layered Model
Foldables are interactive graphic organizers of content and concepts.
For more see the associated handout or go to: http://www.dinah.com/
Gain experience with foldables by creating a foldable of your own or the layers of the
Earth. Include in your foldable - continental crust, oceanic crust, lithosphere,
asthenosphere, mantle, outer core, inner core. AND the chemical and physical
characteristics of the layers. Chapter 8 is especially helpful in understanding the
properties of the different layers and how we know what those properties are.
Part 2: Scale Model
This activity integrates math, geometry, Earth science, individual effort and group
cooperation. Adapted after the exercise by Larry Braile at Purdue University.
See: http://web.ics.purdue.edu/~braile/edumod/earthint/earthint.htm
Your assignment is to create a scale model of a “slice” of the interior of the Earth’s
interior.
Materials:
two 11” x 17” sheets of paper taped together along the short side*
meter stick
pencil
~ 70 cm long string with loop at one end
transparent tape
colored pencils, crayons or felt pens
Draw a light center line and “width lines” (short dashed lines on
“construction detail”, Figure 1) on the 34” x 11” paper (two 11” x 17” sheets of paper
taped together) and construct a scale model of a slice (like a “pizza slice”) of the Earth’s
interior. The scale is 1:10 million or 1 cm = 100 km (1 cm on the model represents 100
km in the actual Earth), resulting in a slice with a radius of 63.7 cm corresponding to the
real Earth’s radius of 6371 km (10 million times the size of the scale model). Using the
dimensions shown on the “construction detail” drawing (Figure 1) will provide a 15
segment of the Earth’s interior.
Procedure:
Once the surface arc line (draw using the string with a loop and a pencil with the length
from the center point to the pencil in the loop being 63.7 cm) and the straight (angle)
lines have been drawn, the light pencil lines can be erased. Complete the scale model
slice of the Earth by drawing arcs at the appropriate radii corresponding to the Moho
(Crust-Mantle), Lithosphere-Asthenosphere, Transition Zone, Core-Mantle, and Outer
Core-Inner Core boundaries as given in Table 1 and illustrated on the Earth’s Interior
Structure diagram (Figure 2).
For the first two boundaries below the surface (Moho and Lithosphere-Asthenosphere), it
is easier to measure downward (0.35 cm and 1.0 cm) from the surface to adjust the length
of the string. Note that converting the depth and radius measurements, in kilometers on
the Table, to the 1:10 million scale, one can simply move the decimal two places to the
left and the number will be in cm. For example, 6371 km is 63.71 cm at the 1:10 million
scale (see Table 1).
Label the boundaries and layers of the Earth and color the various layers representing
spherical shells. Use these colors to enhance visibility and imply relative temperature in
the Earth’s interior: inner core - white, outer core - yellow, mantle (below the
lithosphere) - orange, upper mantle - red, lithosphere - brown. Label these regions as
well.
Cut out your scale model slice and bring into class so we can mount them on the wall.
Actual
Value
Scale Value
(1:10 million Scale)
6371 km
______cm
Depth* to base of the crust (average)
35 km
______cm
Depth* to base of lithosphere (average)
100 km
______cm
Depth* to base of upper mantle
670 km
______cm
Depth* to core-mantle boundary
2885 km
______cm
Depth* to outer core-inner core boundary
5155 km
______cm
Radius of Earth
*Measure downwards from the surface after drawing the arc representing the surface at a
distance of 63.7 cm from the Earth’s center and drawing the diagonal lines completing
the “pie-shaped slice” of the Earth.
Figure 1. Dashed lines are light pencil lines (draw first) that can be erased after the solid lines
of the "slice" are drawn.
s:
Figure 2. Earth's interior structure. See Table 2 for information about layers (spherical shells)
and boundaries.
If they can do this so can you!
Earth’s interior
structure – “pie
slice model”
http://web.ics.purdue.edu/~braile/new/Journey2004NSTASeattle.ppt#15
Earth’s interior
structure – 3-D
Earth model