LESSON 15
INVESTIGATING PLATE
MOVEMENT AND FAULTS
INTRODUCTION
What does the word “model” mean to
you?
Miniature version
Used for study
Something’s too large to view
OBJECTIVES
Describe what a model is and
distinguish models from real objects or
events.
A representation of an object or event
that is too large, too small or
complicated to be viewed or studied
Classify materials as either brittle or
ductile.
Investigate the effects of applying a
force to a model of a fault.
Let’s view the video to
answer the questions:
Record the following in your notebooks:
A. What occurs at a Transform fault?
B. How does plate movement cause
earthquakes at a transform fault?
MODELS
A. How are the map and computer images
used in this lesson like the real earth? How
are they different?
The map and computer images are models
of the earth.
B. What are some examples of models?
Globe, map, tornado in a bottle
C. Write a working definition for the word
“model”.
.
Let’s look at the models we’ll use for this
lesson.
Inquiry 15.1
Using a Simple Model of
Plate Movement
Look at the blue and green foam pads
used in this activity and record their
properties.
Density, appearance, thickness,
weight, and size.
Predict
How would each pad respond if we did
the following:
Pulled on the pad from opposite ends
Pushed on the pad at opposite ends
Slid two pads past one another
Collided two pads by pushing them
together
Test and Record
As each foam pad is demonstrated,
record in your notebook what happens.
Use a table to record your observations.
pull
push slide collide
Blue
Green
REFLECTIONS 15.1
A. How did the pads behave when pulled
from opposite ends?
The pads were stretched thin. The blue pad
was more “stretchy”.
B. How did the pads behave when
compressed?
The pads folded—resembling mountains
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?
The thin, blue, dense pads represented
oceanic plates. The thick green pads
represented continental plates.
D. How did the density of the pads affect the
way they behaved when you made them
collide?
The dense blue pads always moved beneath
the less dense green pads.
E. When do colliding plates on the earth
form mountains?
Mountains form when two continental plates
of a similar density collide.
F. When do colliding plates form trenches?
Trenches form when a dense oceanic plate
collides with a less dense continental plate.
G. Why would a more dense oceanic plate
slide under a less dense continental plate?
Something more dense usually moves
beneath something less dense.
H. Can plates ever move without
forming new land? If so, when?
No new land forms when plates slide
past one another.
I. How do you think colliding plates on
the earth cause earthquakes?
Colliding plates either bend or fracture
the land; earthquakes can form when
rock fractures.
Read pgs. 174, 175
Colliding, Sliding, and
Separating Plates
INQUIRY 15.2
Using the Moving Plates
Model
Turn to page 176 in your
Catastrophic Events book
and follow the procedure
listed as it’s demonstrated
for you.
REFLECTIONS 15.2
A. How do you think the Moving Plates
Model shows what happens on the earth
when two plates separate?
It shows the form they took as they
moved.
B. What causes the ocean floor to
separate and grow?
Newly melted rock rises and pushes
aside the old rock.
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?
A trench forms
D. What patterns did you observe in the
shapes of Africa and South America?
They fit together like puzzle pieces.
E. How did the shapes of these
continents compare with the shape of
the Mid-Atlantic Ridge?
The MAR has the same shape as the
coastlines of these continents, which
border the Atlantic. This is because the
continents broke apart as the ridge
formed.
F. What landform is created when plates
separate? Give an example.
A ridge forms. Ex: The Mid-Atlantic
Ridge.
G. What landform is created when two
continental plates collide? Give an
example.
A mountain forms. Ex: The
Appalachian Mountains (North Amer)
INQUIRY 15.3
Investigating Faults
With Models
Turn to page 179, 181 in your
Catastrophic Events book and
follow the procedure listed on
these pages.
REFLECTIONS 15.3
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.
The greater the friction, the more force is
needed to rupture the fault. The hooks and
loops of the Velcro act like protrusions that
connect the rock across the rock.
B. Under what conditions did the blocks
rupture more abruptly?
The greater the force applied to the
block, the more abrupt the rupture.
C. Under what conditions did the block
slip (more slowly) but not rupture?
When two strips of loop Velcro are side
by side, the friction along the fault was
at its lowest. When resistance along a
fault is low, blocks of rock can slip
without faulting.
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?
Wrinkles in a sidewalk or on a road are
signs that pressure is building up along
a fault. This is called “creep.”