Plate Tectonics Activity
Grant Lockridge
A. Educational Standard/s Addressed
Standard 8-3: The student will demonstrate an understanding of materials that
determine the structure of Earth and the processes that have altered this structure.
B. Performance Objectives: The following South Carolina Scientific inquiry
Indicators are the focus of the lesson.
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Indicator 8-3.6: Explain how the theory of plate tectonics
accounts for the motion of the lithospheric plates, the geologic
activities at the plate boundaries, and the changes in landform
areas over geologic time.
Indicator 8-3.7: Illustrate the creation and changing of landforms
that have occurred through geologic processes (including volcanic
eruptions and mountain-building forces).
Indicator 8-3.8: Explain how earthquakes result from forces
inside Earth.
C. Materials:
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Foam blocks cut to a variety of shapes (done before students
arrive)
Felt pens
Manila folders or thin poster board
Rubber cement
Styrofoam core poster board
Razor blade knife
Metric ruler
D. Procedures: (Note** Activity designed to be completed in station format)
(Braile, 2000).
Station 1 (extensional/normal faulting)
1. Lift the 3 block system off of the table.
2. Slowly move the outer blocks apart and record the motion
of the block in the middle.
3. Draw a picture of the process you just witnessed.
Station 2 (Convergent/Compressional/Reverse faulting)
1. Lift the 3 block system off the table.
2. Slowly move the outer blocks together and record the
motion of the block in the middle.
3. Draw a picture of the process you just witnessed.
Station 3 (Strike-slip/Transform faulting)
1. The two block system should remain on the table
2. Slide the blocks in the direction of the large arrows
3. Draw a picture of the process you just witnessed.
Station 4 (earthquake/elastic rebound theory example)
Top View
20cm
1/2 cm
wide
slits
30cm
10cm
1 cm
wide
tabs
1. Leave the foam blocks on the table.
2. Slowly and continuously slide the blocks in the direction of
the large arrows.
3. Record relevant observations pertaining to the movement
of the “fingers”.
4. Draw a picture of the processes you are seeing.
Note** As the plates move slowly with respect to each other (just as Earth’s lithospheric plates move at
speeds of centimeters per year), the area of the plates adjacent to the fault (the tabs) becomes progressively
bent (deformed), storing elastic energy. As the process continues, some parts of the fault zone will “slip”
releasing some of the stored elastic energy. This slip occurs when the stored elastic energy (bending of the
tabs) results in a force along the fault which exceeds the frictional strength of the tabs that are in contact.
Sometimes, only small segments of the fault zone (one or two tabs) will slip, representing a small
earthquake. At other times, a larger segment of the fault will slip, representing a larger earthquake.
Station 5 (Convergent Plate Boundary and Subduction)
1. Arrange 2 tables of identical height next to each other and
about 30 cm apart as shown in the figure above.
2. Place 2 pieces of foam on the tables and begin to move one
piece (the one without the cardboard edge toward the
other).
3. Describe the processes that you see.
4. Draw a picture of the process.
Note** Earthquakes commonly occur along the length of the subducted slab and compressional structures
(folds and faults) are often associated with the compressional zone near the colliding plates. The
subducted lithosphere consists of relatively low-melting-point rocks (sediments and oceanic crust
form the upper layers of the oceanic lithosphere) which can melt at depths of 100-150 km as the slab
is subducted into the mantle. These molten materials can then ascend through the overlying mantle
and crust and form volcanoes which are often situated in a linear chain or arc about 100-200 km
away from the collision zone. A deep ocean trench also forms above the point of convergence of the
two plates as the oceanic lithosphere is bent downwards by the collision.
Station 6 (Divergent Plate Boundary and Mid-ocean Ridge Spreading)
1. Slide the two foam squares away from each other about 2
cm (this process represents the passage of time and the
extension of the lithosphere in the region of the ridge crest
by tectonic motions)
2. Place the two strips labeled “4” (million years) in the space
that is created
3. Attach one strip to the large square on it’s side with pins.
4. Continue this process until the two strips labeled “0” are in
place.
5. Describe the processes you have seen.
6. Draw a picture of the process.
Note** In the real mid-ocean ridge, a void space or opening between the plates created by the spreading
process, would not actually develop. Instead, as extension occurs, volcanic and igneous intrusion processes
will relatively continuously fill in the extended lithosphere, in the process creating new lithosphere.
Because the oceanic crustal layer in this new lithosphere is formed from igneous (volcanic and intrusive)
processes, it cools from a liquid and the rocks acquire a remanent magnetic direction that is consistent with
the Earth’s magnetic field direction at that time. Because the Earth’s magnetic field occasionally reverses
its polarity (north and south magnetic poles switch), the lithosphere created at mid-ocean ridges displays
“stripes” of normal and reversed magnetic polarity crust approximately parallel to the ridge crest.
Works Cited
Braile, L. W., 2000. Teaching About Plate Tectonics and Faulting Using Foam Models.
Accessed Oct. 2010. Purdue University.
http://web.ics.purdue.edu/~braile/edumod/foammod/foammod.htm#_ftn1