Transcript Chapter 4 Babbey

Chapter 4
Plate Tectonics
Section 1: Earth’s Interior
• Geologists use 2 types of evidence to see
what’s inside Earth:
– Rock Samples
– Seismic waves produced by earthquakes
3 Layers of the Earth
• 1. Crust: the outer layer of the Earth that
includes dry land and the ocean floor.
• 2. Mantle: a layer of hot, solid rock below the
surface of the Earth. It has 3 layers:
– Lithosphere: rigid, stony layer
– Asthenosphere: soft, weak, solid layer
– Lower Mantle: solid material
• 3. Core: the metallic center of the Earth
– The outer core is liquid metal
– The inner core is a dense ball of solid metal
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What’s Inside the Earth Lab?
1. Title: How do
Page 132
Scientists find out
what’s inside Earth?
2. Read through the
procedure.
3. Copy Data Table.
4. Perform Experiment.
5. Analyze data: Answer
the “Think it over:
inferring” questions in
the box on page 132
Canister Your Guess
Number
Actual Material
1
2
3
4
5
6
-When you are done, answer
questions 1 and 2 on page 139
-Write out the questions and the
answers.
Results
Canister Number
1
2
3
4
5
6
What’s inside?
Section 2: Convection and the Mantle
• Heat from the core of the Earth moves out
through the mantle to the crust.
3 Types of Heat Transfer
• 1. Radiation is the transfer of energy through
space (sunlight or fires).
• 2. Conduction is heat transfer within a
material or between 2 materials that are
touching.
• 3. Convection is heat transfer by movement of
currents within a fluid.
• Density is the measure of how much mass
there is in a volume of a substance.
Convection Currents
• A convection current is the flow that transfers
heat within a fluid.
• These change when temperature, density, or
gravity act on the fluid.
Art Project
• Create a 4 Square Art project for the following
words:
– Radiation
– Conduction
– Convection
– Crust
• Each square must include the WORD, the
DEFINITION, and a colored DRAWING.
• If you finish early, do questions 1-3 on page 143
Section 3: Drifting Continents
• Continental drift states that continents are
always slowly moving across Earth’s surface
Pangaea
• 300 million years ago, the continents drifted
together to form a super continent called
Pangaea
3 Evidences for Continental Drift
• 1. Land features: continents fit together like
puzzle pieces
• 2. Fossils: ancient organisms preserved in rock
• 3. Climate Change: places are sometimes
warm and sometimes cold
Pangaea Project
• 1. Label each continent and color each one a
different color.
• 2. Cut out the 7 continents. Ignore tiny
islands.
• 3. Glue them into your notebook as they were
in Pangaea. See page 146 to help guide you.
• When you are finished, answer questions 1-3
on page 148. Write the question & the answer.
Section 4: Sea Floor Spreading
• Sea floor spreading is when the sea floor
spreads apart along both sides of a mid-ocean
ridge as new crust is added.
• A mid-ocean ridge is an undersea mountain
chain beneath Earth’s surface
• They are mapped using sonar, a device that
bounces sound waves off undersea objects.
3 evidences for sea floor spreading
• 1. Molten material: lava and igneous rock have
been found underwater
• 2. Magnetic stripes: iron is found in the ocean
floor
• 3. Drilling samples:
samples of the
ocean floor find
both young and old
rocks
Subduction at trenches
• Deep-ocean trenches are underwater canyons
• Subduction occurs here, where parts of the
ocean floor sink into the trenches and back
into the mantle.
Modeling Sea Floor Spreading
p. 156
• We will follow the directions on page 156-7 to
create models showing sea floor spreading.
Section 5: The Theory of Plate
Tectonics
• The lithosphere is separated into sections
called plates.
• These plates are in constant, slow motion,
which is the theory of plate tectonics.
• Plate tectonics can cause earthquakes,
volcanoes, mountains, and deep ocean
trenches.
Plate Boundaries
• Faults, or plate boundaries, are breaks in
Earth’s crust where rocks have slipped past
each other
3 Plate Boundaries
• 1. Spreading Boundary: plates move apart
• 1. Colliding Boundary: plates come together
• 3. Sliding boundary: two plates slip past each
other, moving in opposite directions
Modeling Mantle Convection
Currents, page 163
• We will perform the experiment on page 163
to model convection currents