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Goswick
EES 3.1
Names: ____________________
Date: ____________________
Period: ____________________
Pizza Earth Lab:
Develop understanding of the structure of the Earth’s interior (and ultimately,
relationships to plate tectonics, occurrence of earthquakes and volcanoes, and the origin of the Earth’s
magnetic field, etc.) by constructing a scale model of a “slice” of the interior of the Earth and studying
the material properties of Earth’s interior. The activity also provides useful practice with the concept of
scale.
Objective:
Materials: ruler, 2 sheets of paper, tape, colored pencils (or markers)
Table 1. Measurements for Earth’s Interior Structure (“Pie-Slice”) Activity.
Actual
Value
Scale Value
(1:10 million Scale)
6371 km
63.7 cm
Depth* to base of the crust (average)
35 km
0.35 cm
Depth* to base of lithosphere (average)
100 km
1.0 cm
Depth* to base of upper mantle
670 km
6.7 cm
Depth* to core-mantle boundary
2885 km
28.9 cm
Depth* to outer core-inner core boundary
5155 km
51.6 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.
Procedure:
1. 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.
2. Draw the surface arc line and next draw the straight (angle) lines to complete your slice.
Goswick
EES 3.1
Figure 1. Dashed lines are light pencil lines (draw first) that can be erased after the solid lines of the "slice" are
drawn.
3. The light pencil lines can now be erased.
4. Complete the scale model slice of the Earth by drawing arcs at the appropriate radii
corresponding to the Moho, 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 LithosphereAsthenosphere), 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).
5. Label the boundaries and layers of the Earth and (optionally) color the various layers
representing spherical shells.
 Suggested coloring of slices to enhance visibility and imply relative temperature in
the Earth’s interior is: inner core - white, outer core - yellow, mantle (below the
lithosphere) - orange, upper mantle - red, lithosphere - brown.
6. Cut out each of the scale model slices and mount them on wall. (where designated by the
teacher!)
7. Twenty-four of the slices (using the 15 slice produced by the measurements shown on the
attached “construction detail” drawing, Figure 1) can be arranged into a complete circle
representing a 1:10 million scale cross section through the entire Earth. Label the main regions:
lithosphere, mantle, outer core, inner core.
Extensions:
1.One of the confusing concepts of Earth structure is the distinction between chemical layering (crust,
mantle and core) and mechanical layering (lithosphere, asthenosphere and mesosphere). The scale
model illustrates all of these layers on a single diagram.
Nicholson
EES 8.4
Figure 2. Earth's interior
structure. See Table 2 for
information about layers
(spherical shells) and
boundaries.
Figure 3. Perspective view of
Earth cross section. (Modified
from figure on page 57 of
Seismic Sleuths, FEMA/AGU.)