Inside the Earth
Things to Know
What do the layers of the Earth
look like?
Check the following terms and
definitions to see if they are in
your journal.
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Inner core – the solid inner core of the Earth.
Pressure makes the iron found there a solid
mass.
Outer (metallic) core – the liquid core area of
the Earth. It is mostly made of iron.
Upper mantle – thin layer of the mantle made
of rigid rock.
Lower (convecting) mantle – the largest part
of the Earth’s interior. Rock found at this layer
will flow very slowly.
Asthenosphere –the lower part of the upper
mantle. Lithospheric plates slide on this layer.
Layers of the Earth
Now check for these terms and
definitions
Crust – the outermost surface of the
Earth
 Lithosphere – a layer of Earth that
includes the crust and a thin part of the
upper mantle
 Core – the center of the Earth; it is
divided into the inner core and the outer
core
 Mantle – the warm, flowing, solid layer of
Earth between the crust and the core
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More on the layers of the Earth
Now check your journal for these
terms and definitions
Lithospheric Plates – Large pieces of Earth’s
lithosphere that move over the
asthenosphere
Oceanic Plates – Thin lithospheric plates that
are made of basalt and form the ocean floor;
denser than continental plates.
Continental Plates – Thick lithospheric plates
that made of andesite and granite and form
the continents; less dense than oceanic
plates.
Check your journal for these terms
and definitions
 Convection
is the process of hot
material from deep within the
Earth rises while cooler material
near the surface sinks. When the
warmer material cools, it becomes
denser and begins to sink back
down. The motion of the
convecting mantle drags tectonics
plates sideways.
Convection Cells
STOP
Read page 99 in
“Inside the
Restless Earth”
Now check for these terms and
definitions in your journal
Plate tectonics – A theory explaining
how the pieces of Earth’s surface (the
plates) move.
 Pangea - An ancient, huge landmass
composed of earlier forms of today’s
continents; an ancient supercontinent.
 Continental drift – The idea that
continents move around on Earth’ surface.
 Alfred Wegener – The scientist who first
looked at the idea of continental drift.
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STOP
Read pages 95
and 96 in “Inside
the Restless
Earth.”
Check your journal for these terms
and definitions
Mid-ocean Ridge – A long chain of
undersea mountains
Sea-floor Spreading – A hypothesis that
new sea floor is created at mid-ocean
ridges and that, in the process, the
continents are pushed apart from each
other.
Mantle Plume – Heated lower mantle rock
that rises toward the lithosphere because
it is less dense than surrounding mantle
rock.
More terms and definitions to
check for
Harry Hess – A scientist who,
during World War II,
discovered the proof that
Wegener’s theory was right.
Magnetic Reversals –
Evidence of sea-floor
spreading coming from
magnetic reversals recorded
in the rock of the ocean floor.
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Divergent Boundary
– A lithospheric plate
boundary where two
plates are moving
apart.
Now check for this term and
definition
Convergent Boundary
– A lithospheric plate
boundary where two
plates come together.
Last check for terms and
definitions in your journal
Transform Fault Boundary – A
lithospheric plate boundary
where two plates slide by each
other.
Subduction – A process that
involves a lithospheric plate
sinking into the mantle.
Deep-ocean Trench – A valley
in the ocean created when one
lithospheric plate subducts
under another.