Download Modeling Plate Movements

Modeling Plate Movements
Purpose:
To create a model of tectonic plates and study the interactions of these plates as they slowly move on the asthenosphere.
Background:
The theory of Plate Tectonics states that the Earth’s crust is composed of major pieces or plates. These plates “ride” on the hot plasticlike upper mantle known as the asthenosphere. This theory also states that these plates are in motion, creating a variety of interactions
at plate boundaries. At active plate boundaries, plates may do the following: converge, diverge, or slip (lateral movement) past each
other. In addition, some plates appear to be inactive. In this activity you will investigate interactions that take place along the plate
boundaries.
Procedures:
There are four parts to this activity. You MUST follow the directions in the order they are given!
PART I: DIVERGENT PLATE BOUNDARIES (Oceanic – Oceanic Plates)
1.
Break a whole graham cracker in half following the perforations on the cracker. You should have 2 graham cracker squares.
2. Using a plastic knife, spread a thin layer of frosting on the center of the wax paper (about the thickness of a playing card).
3. Lay the two pieces of graham cracker on the frosting and gently pressing down, push them together. Now you are ready to
begin modeling a divergent plate boundary.
4. To imitate the result of diverging oceanic plates, press down lightly on the crackers as you slowly push them apart. Do not
push the crackers more than one centimeter.
5. Describe your observations below & answer the questions below.
Observations:
Questions
1.
What happens to the frosting between the graham crackers (how does it look)?
2. What does each of the graham crackers represent?
3. What does the frosting represent?
4. Where does this type of plate boundary activity take place on Earth?
5. What type of feature is produced by this type of plate movement?
PART II: CONVERGENT PLATE BOUNDARIES (Continental-Oceanic Plates)
1.
Remove one of the graham crackers from the frosting.
2. Obtain a piece of Styrofoam.
3. Lay a graham cracker and the Styrofoam piece end to end against each other on top of the frosting. The graham cracker
represents the thin, dense oceanic plate. The Styrofoam represents the thick, less dense continental plate.
4. Now you are ready to model a convergent plate boundary!
5. Slowly push the graham cracker and Styrofoam towards each other. Gently push the graham cracker under the Styrofoam.
This models what occurs on Earth’s surface as an oceanic plate is subducted under a continental plate.
6. Make observations & answer the questions below.
Observations:
Questions
1.
What type of plate does the Styrofoam represent?
2. What type of plate does the graham cracker represent?
3. What happens when a piece of crust is subducted?
4. Where does this type of boundary activity take place on Earth?
5. What 2 features are formed along the subduction zone?
PART III: CONVERGENT PLATE BOUNDARIES (Continental-Continental Plates)
1.
Reuse the two graham cracker squares used in Part I & Part 2.
2. Break the graham cracker into 4 rectangles following the perforations. Set aside two graham cracker pieces for Part IV.
3. Using two graham cracker rectangles, dip one end of both graham crackers about 2 cm into a beaker of water. Immediately
remove the crackers and lay them end to end on the frosting with the wet ends nearly touching. Now you are ready to model a
convergent plate boundary!
4. Slowly push the two graham crackers together.
5. Make observations & answer the questions below.
Observations:
Questions
1.
What does the graham cracker represent?
2. In what way are the wet graham crackers more like the real crustal plates than are the dry graham crackers?
3. What feature is represented where curling and folding occurred at the ends of the wet graham cracker?
4. Where does this boundary activity take place on Earth?
PART IV: TRANSFORM FAULT PLATE BOUNDARIES
1.
Use the last two graham cracker pieces for this part of the lab.
2. Fit the two pieces together end to end on top of the frosting on the wax paper.
3. Now you are ready to model a transform plate boundary!
4. Place one hand on each of the graham crackers and push them together by applying steady, moderate pressure. At the same
time, also push one of the pieces away from you while pulling the other toward you. If you do this part correctly, the graham
cracker should hold while you increase the push-pull pressure, but will finally break from the force you apply laterally.
5. Make observations & answer the questions below.
Observations:
Questions
1.
Where does this type of boundary activity take place on Earth?
2. What famous fault is associated with this type of movement?
3. As you modeled this type of fault, nothing happened at the beginning, but as the pressure increased, the graham crackers
finally broke. How is this similar to the situation in California?