Download 8.9AB: Plate Tectonics

8.9AB: Plate Tectonics
Earth and Space
Activity Description:
Students will use a small size chocolate nugget candy bar to model the three types
of plate boundaries.
Materials:
1 small size chocolate nugget candy bar (per student)
1 roll of paper towels (per teacher)
1 Student Attachment: Milky Way Plate Boundaries (per student)
Teacher Procedure:
Before the start of the lesson, make sure you have the listed materials and
necessary student attachments prepared.
 
Have a paper towel and candy bar set at each student work station
Use the following questions to begin student discussion on the topic:
1.
2.
3.
What are some consequences of plate tectonics?
  A convergent boundary occurs when two plates collide. Depending upon
the type of crustal material at the boundary of the colliding plates,
volcanoes, mountains and ocean trenches can form. A divergent boundary
occurs when two plates move away from one another creating rift valleys in
continental material and ridges in ocean basins. A transform boundary
occurs as two plates move past each other causing faulting and earthquake
activity.
What does the theory of plate tectonics say about the plates?
  According to the theory of plate tectonics, Earth’s lithosphere is made of
plates that move and cause changes to crustal features at plate
boundaries.
What are some scientific discoveries that support the theory of plate
tectonics?
  In the early 20th century, Alfred Wegener developed early theories of
continental drift, indicating that the continents of Earth move and historically
were in different positions than they are currently.
  In the 1960s, scientific discoveries about seafloor spreading, combined with
earlier theories of continental drift, led to a theory of plate tectonics.
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8.9AB: Plate Tectonics
Earth and Space
Procedure:
1. Distribute attachment and candy bar to each student.
 Caution students to not open the candy bar until told to do so by the
teacher.
2. Direct students to unwrap the Milky Way and set it on the wrapper.
3. Direct students to push their finger into the surface of the candy bar to crack
the chocolate layer in several places. Have students draw their candy bar
while looking down on it.
 Explain that these cracks are like the cracks in the Earth’s surface and the
pieces of chocolate on the top are the tectonic plates. The plates are sitting
on the mantle, which is represented by the caramel later.
4. Direct students to gently push the right side of the candy bar away from them
and pull the left side toward them. Remind them to watch the plates as they
the slide on the plates. Have students draw their candy bar and how the
positions of the plates have changed.
 Explain that this is an example of a transform boundary like the San
Andreas fault in California. The plates are sliding past each other causing
earthquakes.
5. Direct students to pull the candy bar apart about 2 inches and watch what
happens to the plates and mantle. Have students draw their candy bar and
what happened at the plate boundary.
 Explain that this is an example of a divergent boundary like the one found
at the mid -ocean ridge.
6. Direct students to push the two pieces together and try to build a mountain.
Have students draw their candy bar and the mountain they built.
 This step is pretty messy so you may want to give the students a damp
paper towel at this point. You may also tell students they should destroy
the evidence by eating the candy bar, if they wish. Explain that this is an
example of a convergent boundary like the one found where India and
China meet. Mount Everest is along this boundary.
7. Direct students to clean up their area with the damp paper towels.
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8.9AB: Plate Tectonics
Earth and Space
Student Attachment: Candy Bar Plate Boundaries
1.  Push your finger into the surface of the candy bar until it cracks. Draw the top
of your cracked candy bar below. Label the plates and the mantle.
2.  Gently push the right side of the candy bar away as you slide the left side
toward you. Draw the top of the candy bar showing how the plates have
moved. Label this a Transform Boundary.
3.  Pull the candy bar apart about 2 inches and watch how the plates and mantle
shift. Draw the top of the Milky Way showing the changes that took place.
Label this a Divergent Boundary.
4.  Push the two pieces together until a mountain is formed. Draw the top of the
Milky Way showing what changes have taken place. Label this a Convergent
Boundary.
5.  Please clean up, disposing of the candy as you see fit.
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