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Catastrophic Events
Part II
Lesson 15: Investigating Plate Movement and Faults
FQ: How does plate movement affect landforms?
Learning Targets:
 I understand scientists and engineers construct models to help them
understand how complex systems behave.
 I understand lithospheric plates on the surface of the earth slide past one
another, collide, and separate at a rate of 2 to 20 cm per year.
 I understand landforms-mid-ocean ridges, trenches, and mountains-form
as a result of plate movement.
 I understand rock responds to the forces caused by plate movement by
either folding (bending) or fracturing (breaking).
 I understand faults are fractures in the earth’s crust and upper mantle
along which measurable movement of rock has occurred.
 I understand earthquakes occur along faults and are common along plate
boundaries.
Student Objectives:
 Describe what a model is and distinguish models from real objects or
events.
 Use models to simulate the movement of Lithospheric plates as they
collide, separate, and slide past one another.
 Use a globe and a map to find evidence of plate movement and to identify
landforms- such as mid-ocean ridges, mountains, and trenches- that result
from plate movement.
 Classify materials as either brittle or ductile.
 Investigate the effects of applying a force to a model of a fault.
Getting Started:
1. Look at the wall map called “Earth’s Fractured Surface” with your class.
How is this map different from others you have seen? How is it the
same?
2. Review your homework (Student Sheet 14.1) from Lesson 14 with your
teacher. You may be asked to plot a volcano data point on the wall map.
Describe any patterns you notice in the location of volcanoes and
earthquakes.
3. Look at the plates shown on the map. Describe any relationship you see
between the locations of earthquakes and volcanoes on the earth and the
boundaries, or outer edges, of plates. What ideas do you have to explain
this relationship?
4. View the CD-ROM, The Theory of Plate Tectonics. How do plates move?
How does plate movement cause earthquakes, volcanoes, mountains, and
trenches? Discuss your observations with your class.
5. Discuss what you know about models with your class.
6. Look at the models you will use in this lesson. Which kind of plate
boundary do you think you will model with each one? Discuss with your
class why and how models are used in the science classroom.
7. Pick up one copy of Student Sheet 15.1: Plotting Earthquakes by Depth.
You will complete the first section of it for homework. You will finish the
questions after you complete Inquiries 15.1 and 15.2.
Inquiry 15.1: Using a Simple Model of Plate Movement
1. In your group, examine the foam pads. Describe their properties.
Consider density, appearance, thickness, weight, and size. Record your
group’s ideas in your science notebook.
2. Predict how you think each pad would respond if you did the following:
a. Pulled on the pad from opposite ends.
b. Pushed on the pad at opposite ends toward the center.
c. Slid two pads past one another.
d. Collided two pads by pushing them together.
Discuss your predictions with your group.
3. Test your predictions. Pull on one pad. What happens to its appearance?
What happens to its volume and size? In your notebook, draw a picture
of what happens to the pad.
4. Hold one foam pad by its opposite ends, as shown in Figure 15.1.
Compress the pad by pushing your hands toward each other. In your
notebook, draw a picture of what happens to the pad. Repeat this
process with the other type of pad. Now try stacking the pads on top of
each other. Compress them. What do you observe? Record your results.
5. Place two pads of the same thickness side by side on the desk or table.
Slide them past one another, as shown in Figure 15.2. Record your
observations in your notebook. Now try this with one thick and one thin
pad. Did your results change?
6. Now work over a 10-cm opening between two desks or thick books. Place
two thick pads side by side. Make the pads collide (push them together),
as shown in Figure 15.3(A). What happens?
7. Place one thick and one thin pad side by side and make them collide.
Again, work over a 10-cm opening between two desks or books if
possible, as shown in Figure 15.3(B). With your group, discuss what
happens. How does the behavior of the pads differ from their behavior in
procedure Step 6? Why do you think this happens? Record your ideas
and drawings in your notebook.
8. If possible, examine a relief globe. Look for evidence of trenches and
mountains. Then discuss with your group how you think they formed.
(Think about the behavior of your pads and what you learned about plate
movement from the CD-ROM.)
9. Clean up. Prepare your station for the next group.
Reflecting on What You’ve Done:
1. Answer these questions in your notebook.
a. How did the pads behave when pulled from opposite ends?
b. How did the pads behave when compressed?
c. If oceanic plates are colder, denser, and thinner than continental
plates are, which pad do you think represented oceanic plates?
Which pad represented continental plates?
d. How did the density of the pads affect the way they behaved when
you made them collide?
e. When do colliding plates on the earth form mountains?
f. When do colliding plates on the earth form mountains?
g. Why would a more dense oceanic plate slide under a less dense
continental plate?
h. Can plates ever move without forming new land? If so, when?
i. How do you think colliding plates on the earth cause earthquakes?
2. Read “Colliding, Sliding, and Separating Plates.”
Inquiry 15.2: Using the Moving Plates Model
1. Set up your Moving Plates Model as shown in Figure 15.4. Make certain
the belts on top of the lid are black, with red just about to emerge from
the slit in the center.
2. Have one member of your group hold both knobs. Try to move the knobs
in opposite directions at the same time. What happens?
3. Reset your Moving Plates Model by turning the knobs so that only black
belts show on top and red belts are directly below the slit. Very slowly,
turn the knobs so that both belts move away from the slit in the center.
How are the belts changing on either side of the center slit? What
happens to the black belts as they get near the edges of the lid? Discuss
your answer with your group.
4. Flatten out the dough. Make it as think as possible. Place the continent
stencil on the top of the flattened dough. Outline each continent-North
America, Africa, and South America-in the dough using a sharp toothpick.
Remove the dough continents. What observations can you make about
their shapes? Look on a map and discuss with your group what landforms
exist on these continents and why you think they are there.
5. Reset the belts again. Place two of the three continents over the center
slit. Try different combinations. Which continents seem to fit well
together? Why do you think this is so? Discuss these questions with your
group.
6. Place South America and Africa together like puzzle pieces on the black
belts and over the center slit, as shown in Figure 15.5. Slowly turn the
knobs so that the continents move away from one another. Move the clay
models slightly, about 8 cm. This represents movement of the continents
over millions of years.
7. Look at your Catastrophic Events World Map. What patterns do you
observe in the shapes of the continents and the shape of the ridge in the
center of the Atlantic Ocean? What do you think is responsible for these
patterns? How do you think the Atlantic Ocean formed? Discuss your
observations with your group.
8. Place North America and Africa on the outer ends of the belts, as shown in
Figure 15.6. Pinch the outer edges of the continents onto the belt to
secure them. Now you will go back in geological history. Turn the knobs
so that the continents move inward, toward the center slit. What happens
as the continents collide?
9. On your Catastrophic Events World Map, look at North America’s eastern
states. What landforms do you notice there? What process do you think
might have been responsible for forming the mountain range there (called
the Appalachian Mountains)?
10. Look at the relief globe. Do the following with your group, and discuss
the answers to the questions as you work:
a. Feel the globe. What do you observe? How is it different from
other globes you have used?
b. Where on the earth do you see evidence that plates collided in the
past? What evidence do you have that plates may have collided
there? (Answer the next question only if you have already
completed Inquiry 15.1.) Do you think those plates were
continental, oceanic, or both? Why?
c. Where on the globe do you think plates are separating? Find
evidence of this both within continents and under the ocean.
d. Find Japan and the Japan Trench. Feel these areas on the relief
globe. What do you observe about these areas? What do you
think is happening to the two plates that meet at this trench?
e. Find the middle of the Atlantic Ocean, called the Mid-Atlantic Ridge.
Feel this ride on the relief globe. What do you observe about this
landform? What do you think is happening to the two plates
located along the Mid-Atlantic Ridge? Why do you think this ridge
is higher than the rest of the ocean floor?
f. Are there other places on the globe similar to the Japan Trench and
the Mid-Atlantic ridge?
11. Clean up. Remove any dough that may be stuck to the belts of the
Moving Plates Model. Roll the dough back into a ball.
Reflecting on What You’ve Done:
1. Apply what you observed in this inquiry to the earth’s plate boundaries.
Answer these questions in your notebook:
a. How do you think the Moving Plates Model shows what happens on
the earth when two plates separate?
b. What causes the ocean floor to separate and “grow”?
c. Think about what happened to the black belt as it reached the
edges of the model’s lid. What landform is created when the ocean
floor sinks back into the earth?
d. What patterns did you observe in the shapes of Africa and South
America? How did the shapes of these continents compare with
the shape of the Mid-Atlantic Ridge?
e. What landform is created when two continental plates collide? Give
an example.
2. Share your observations with the class.
3. With your class, look at the “Earth’s Fractured Surface” plate boundaries
map. Why do you think there are mountains north of India?
Inquiry 15.3: Investigating Faults with Models
Getting Started:
1. With your class, discuss what happens to rock when plates move.
2. Predict what would happen if you applied a force to a stick at both ends.
Watch as your teacher tests your predictions.
3. Collect a set of brittle and ductile materials for your group. Observe their
properties. Then classify each item as brittle, (breaks when a force is
applied to it), ductile (bends, stretches, or flows when a force is applied),
or both. Record your group’s classifications in your notebook using either
a list or Venn diagram. What other items could you put in these
categories? List them.
4. Discuss your group’s classifications and reasons for choosing each with
the class. Answer the following:
a. Which materials were brittle? Which were ductile? Why did you
classify them this way?
b. How did you apply force to each object? How did each object
respond to that force?
c. Did temperature and pressure affect the behavior of your objects?
If so, how?
d. On the basis of these observations, what do you think are the
conditions that affect how an object responds to a force?
5. The objects that you investigated respond to force; similarly, rocks that
make up plates respond to force-the force caused by plate movement.
Examine the picture of the rock shown in Figure 15.7. How do you think
it became folded? Share your observations with the class.
6. Apply what you learned about brittle and ductile objects to rock on the
earth. Discuss these questions with your class.
a. In what part of the earth might rocks be more brittle and fracture
more easily?
b. How do you think the ability of the rocks to fracture relates to
earthquakes?
Procedure:
1. Discuss with your group what you already know about faults. What
questions do you have about faults? Record your group’s ideas in two
lists in your notebook. Title the lists. Share your ideas with the class.
2. Look at the Fault Laboratory. You will use this model to investigate
movement along a fault where blocks of rock slide past one another.
What do you think will happen when a force is applied to the blocks?
Discuss your hypothesis with the class.
3. Read “Earthquake and Faults, on pages 182-183.
4. Review Steps 8 through 15 of the Procedure with your teacher.
5. Collect one copy of Student Sheet 15.3a for your group. Work with your
group to design an experiment that demonstrates how frictional resistance
along a fault affects how rock moves during an earthquake. Record the
materials and procedure you will use, how you will control all variables
except the one you are testing, what you will look for, and what you will
measure.
6. Share your experimental design with the class.
7. Discuss with the class how you will record your data. If you graph your
data, how will you graph it? Use Student Sheet 15.3b as one way of
recording and analyzing the data you will collect as you experiment with
the blocks. Note that you will conduct trials with no Velcro strips and with
one, two, and three strips.
8. Collect your materials. Use Figure 15.8 to set up your Fault Laboratory.
Make sure that your fault Laboratory is assembled correctly by checking
each of the following steps:
a. Carefully place the block with the hole so that the long strip of soft,
looped Velcro is facing the “fault.” Use the bolt, washers, and wing
nut to fix, or secure, the block with the hole to the plastic box.
b. Notice how each side of the block has a different number of strips
of “hooked” Velcro. For each test, you will rotate the block so
there is more booked Velcro (or frictional resistance) between the
two blocks.
c. Slide the solid block (with no hole) in place next to the fixed block.
Make certain the soft loop Velcro on both blocks is touching and
secure. Use one to two tongue depressors as spacers between the
plastic box and the solid, unfixed block only if the blocks are loose.
This will push the blocks together.
d. Make a loop or tightly knot the cord to the hood on the solid,
unfixed block.
e. Thread the cord through the hole opposite the hook.
f. Use a loop or tightly knot the cord to the spring scale.
9. Experiment freely with the unfixed block. How does the block move when
you pull it? Try putting masking tape across the boundary, or “fault,”
where the two blocks meet. Pull on the block again. What happens to
the tape that indicates stress is building along the fault? Reset the blocks.
Place houses (plastic centimeter cubes) on the blocks along the fault. Pull
on the block again.
10. Remove the tape and houses. Put them aside for now. Collect and
analyze data to find out how the amount of frictional resistance along a
fault affects the way it ruptures. Follow your plan on Student Sheet 15.3a
and Procedure Steps 11 through 15 as you work.
11. Pull on the spring scale, which will apply a sliding force to the unfixed
block. How much force do you have to apply to the block before the fault
ruptures (that is, before the block move abruptly)? Record the maximum
force in your data table under “0,” since you are not using any hooked
Velcro on the blocks, and there is very little frictional resistance along your
fault. Conduct three trials.
12. Now rotate the unfixed block so there is one strip of hooked Velcro along
the fault. Repeat Procedure Step 11. Conduct three trials. Record your
force data each time under “1” on Table 1 on Student Sheet 15.3b.
13. Now repeat these procedures with two strips of hooked Velcro, recording
data under “2” in Table 1 as you do.
14. Finally, rotate the block again and test the force using three strips of
hooked Velcro. Record your data under “3” in Table 1. Place houses
(plastic centimeter cubes) on the blocks. What happens to the houses
during an “earthquake”?
15. Finish Student Sheet 15.3b and the last box on Student Sheet 15.3a.
16. Clean up.
Reflecting on What You’ve Done:
1. Draw conclusions about faults and earthquakes on the basis of your
results. Answer these questions:
a. How did the amount of friction along the fault affect the amount of
force needed to rupture the fault? Use data to support your
answer.
b. Under what conditions did the blocks rupture more abruptly?
c. Under what conditions did the block slip (move slowly) but not
rupture?
d. Think about what happened with the masking tape. Is there any
sign on the earth’s surface that the earth is moving slowly beneath
the crust? (Look at Figure 15.9 and use the caption to answer this
question.)
2. How would you define the work “fault”? Write your definition in your
science notebook.
3. With your class, find one place on the earth where a fault is located.
4. Watch the video Earthquakes.