Name
Date
Class
Effects of Stress
When Earth’s plates move, they produce stress that can change Earth’s surface.
Different types of stress cause different kinds of changes. Here you will
investigate three types of stress: tension, compression, and shearing.
INQUIRY FOCUS Make Models, Classify
Procedure
1. Mold the clay into a solid tube shape, approximately
16 cm long and 4.5 cm in diameter. In the following
steps, you will apply three different kinds of stress to
the clay tube.
Materials
modeling clay
ruler
2. Place the tube on a flat surface. Place your hands at the
ends of the tube. Apply force equally to both ends of tube by pushing your hands
toward each other. In the first box below, draw a diagram showing what your clay
looks like now. Include measurements in your diagram.
3. Reshape the clay into the original tube. This time, grab both ends of the tube and
slowly pull each end in opposite directions. In the second box, draw a diagram
showing what your clay looks like now. Include measurements in your diagram.
4. Reshape the clay into a tube one more time. Wrap your hands around the tube as if
it were the handlebar of a bicycle. Holding onto the tube, push one hand away from
you while pulling the other hand toward you. In the third box, draw a diagram showing what your clay looks like now. Include measurements in your diagram.
Think It Over
In the boxes, classify each type of stress as tension, compression, or shearing.
Think about the original tube of clay. What is the relationship between the types of
stresses and the resulting shapes illustrated in your diagrams?
Name
Date
Class
Modeling Faults
A fault is a break in Earth’s crust along which rock surfaces can slide past
each other. Faults create landforms such as mountains and valleys. There
are three types of faults: normal, reverse, and strike-slip.
INQUIRY FOCUS Observe
Procedure
1. Use the three colors of modeling clay to make a
model of Earth’s layered crust. Use the knife to
cut this model into three equal-sized blocks.
2.
Materials
3 different colors of
modeling clay
plastic knife
Using the knife, cut through the clay of one block,
starting at the top layer and moving down at an angle
to the bottom. Move the clay layers to show what a normal fault would look like.
Draw a diagram in the first box below, labeling the hanging wall and footwall.
3. In your second block, use the knife to create a reverse fault. Cut from the top
layer to the bottom, moving the knife at an angle. Draw a diagram of your model
in the second box, and label the hanging wall and footwall.
4. Use the knife to mark a road on the top layer of your third block. Then use
your knife to create a strike-slip fault that cuts through the road. In the third box,
draw and label a diagram of your model.
Think It Over
Explain the similarities and differences you observed between the normal and
reverse faults.
What happened to the road you marked in the strike-slip fault model? How might
scientists use this observation in nature?
Name
Date
Class
Modeling Stress
Plate movement creates different types of stress in Earth’s crust: tension,
compression, and shearing. Landforms such as anticlines, synclines,
fault-block mountains, and plateaus all form as a result of plate movement.
INQUIRY FOCUS Make Models
Procedure
1. Use the three colors of modeling clay to create a
model of Earth’s crust. Flatten each color of clay into
a thin rectangle and then stack the layers on top of
one another to form a rectangular block.
2.
Use the clay and knife to model the following
landforms: anticline, syncline, fault-block mountain,
and plateau. Use your student edition as a reference, if
necessary.
Materials
3 different colors of
modeling clay
plastic knife
colored pencils
3. Draw a picture of each model you make.
Think It Over
Find another pair of classmates. Take turns explaining your diagrams to each
other. List two facts that you learned by listening to someone else’s explanation.
What type of stress (compression, tension, or shearing) produces each of the
landforms you modeled? How do you think one type of stress can produce
more than one type of landform?