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Plate Tectonics Activity
Background
Plate tectonics theory states that Earth’s crust in composed of 7 major plates and many smaller plates.
These plates move across the hot upper mantle known as the asthenosphere due to convection currents.
With all this motion, the plates are bound to crash into each other or move away from each other. Places
where the plates touch are called plate boundaries. At these boundaries, plates may converge (collide),
diverge (separate), or slide past each other in a lateral motion (transform). In addition, some plates may be
inactive.
Objectives
- Learn how the plates interact with one another
- Learn why some plates sink and others float
- Learn what types of land formations are typical of each type of boundary
Materials
- Graham Crackers
- Whipped cream
- wax paper
Read and follow all instructions for each part, then answer the questions that follow.
Part 1 – Divergent Plate Boundaries
Procedure:
1. Spread a thin layer of whipped cream on your wax paper (about 1 cm thick; the shaving cream
should be wide enough to set your plywood pieces on top)
2. Lay the two double graham crackers side by side on top of the whipped cream so that they touch
3. To imitate the result of diverging oceanic plates, press down on the crackers as you slowly pull
them apart in opposite directions.
4. Remove the crackers and clean off as much whipped cream as you can.
Questions:
1. What were your observations when you pulled the crackers away from each other?
2. What do the double crackers represent?
3. What does the whipped represent?
4. Name a specific location on earth where this kind of boundary takes place.
5. What type of feature does this movement produce?
6. What is the process called that creates new ocean floor from diverging plates?
Part 2 – Convergent Plate Boundaries (Oceanic + Continental)
Procedure:
1. Place one single layer graham cracker on the whipped cream.
2. Lay a double layer graham cracker next to the single layer graham cracker so they are almost
touching, end to end.
3. Push the two plates slowly toward each other and observe which plate rides up over the other. On
the actual surface of the earth, the lower plate is subducted.
Questions:
1. What kind of plate does the single graham cracker represent?
2. What kind of plate does the double graham cracker represent?
3. What happens when a tectonic plate gets subducted?
4. Name a specific location on the Earth where this kind of boundary activity takes place.
5. What features are formed along this boundary?
6. What feature is formed in the ocean along the subduction zone?
Part 3 – Convergent Plate Boundaries (Continental)
Procedure:
1. Take two single graham crackers and place them apart from one another on top of the whipped.
2. Using your fingers only, slowly push the crackers together. Allow the crackers to push up against
each other by pushing down slightly on the back ends of the crackers as you push them forward.
3. Increase your pressure on the crackers if necessary to make them move against each other and
begin to crack.
4. Keep the materials for Part 4.
Questions:
1. What happens to ends of the crackers as they move together?
2. How would the real crust plates differ from the rigid crackers when pushing against each other?
3. What feature do the resulting ends of the crackers represent?
4. Name a specific location on the Earth where this type of boundary activity takes place.
Part 4 – Lateral (Transform) Plate Boundaries (Continental)
1. Fit two single crackers together side to side on top of the whipped cream.
2. Place one and on each of the crackers and push them together by applying steady, moderate
pressure. At the same time, push the cracker on the left away from you and pull the cracker on the
right toward you. The crackers should hold while you increase this push-pull pressure, but will then
finally slip from the opposite forces.
3. Clean up/eat all supplies—use your discretion
Questions:
1. Describe the movement of the plates in this scenario.
2. Name a specific location on the Earth where this type of boundary activity takes place.
3. Nothing happens at the beginning, but as the pressure is increased the wood pieces finally slip past
one another. What is this scenario analogous to with continental plates?
Conclusion:
1. Sketch each boundary
type, labeling the types of plates
and direction of the plate’s motion
for each lab part.
2. Give an example of how
plate movement directly affects
the construction of the Earth’s
surface.
3. Give an example of how
plate movement directly affects
the breakdown of the Earth’s
surface.
4. Based on this lesson and
previous knowledge, put C along
convergent boundaries, D along
divergent boundaries, and T along
transform boundaries on the map
below.
5. Complete the following table.
Type of Margin
Divergent
Motion
Effect
Convergent
Transform
Spreading
Destructive (oceanic
lithosphere destroyed)
Topography
No major effect
Volcanic Activity?
Yes/No
6. Japan, Indonesia, and the Philippines are examples of volcanic island chains that have formed along
subduction zones between plates in the western Pacific.
a. Describe what happens when two tectonic plates collide along a subduction zone.
b. Explain how subduction leads to volcanic activity.
7. Southern California experiences periodic devastating earthquakes along the San Andreas Fault,
which is a transform boundary located along the eastern edge of the Pacific Plate.
a. Describe what happens to the tectonics plates along a transform boundary at the moment
when an earthquake occurs.
b. Describe what happens to the tectonic plates along a transform boundary during the time
between earthquakes.