Download 8th Grade Earth Science

8th Grade Earth Science
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The Earth is Made of 5 Physical
Parts
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Lithosphere
Asthenosphere
Mesosphere
Outer Core
Inner Core
Lithosphere
• The cool, outermost layer of the earth.
• The Lithosphere consists of:
– Crust
– Rigid, uppermost part of the mantle.
• The Lithosphere is divided into 2 huge
pieces called Tectonic Plates.
Asthenosphere
• The solid, soft layer of the mantle below
the lithosphere.
• The Asthenosphere is made up of mantle
rock that flows very slowly, allowing the
tectonic plates to move on top of it.
Mesosphere
• Middle Sphere
• The Mesosphere is the solid lower part of
the mantle below the asthenoshpere.
Outer & Inner Core
• Outer Core
– The outer shell of the Earth’s core
– It is made of liquid iron and nickel.
• Inner Core
– A sphere of solid iron and nickel.
Plate Tectonics
• Plate Tectonics is the theory that the
lithosphere is divided into tectonic plates
that move around on top of the
Asthenosphere.
• There are 3 types of Tectonic Plate
Boundaries:
– Convergent
– Divergent
– Transform
Convergent Boundary
• The boundary that is created when two
tectonic plates collide.
• There are 3 types of Convergent
Boundaries:
– Continental/Continental
– Continental/Oceanic
– Oceanic/Oceanic
Continental/Continental
• When two tectonic plates with continental
crust collide, they buckle and thicken,
pushing the continental crust upward.
Continental/Oceanic
• When a tectonic plate with continental
crust crashes into a tectonic plate with
oceanic crust, the oceanic plate slides
under the continental plate.
• The region where oceanic lithosphere
sinks into Asthenosphere is called a
subduction zone.
Oceanic/Oceanic
• When two oceanic plates collide, one of
the oceanic plates is subducted, or sinks,
under the other.
Divergent Boundary
• The boundary that is created when two
tectonic plates separate.
– Also called rift zones.
• As the two tectonic plates move apart,
magma rises to fill the gap.
– At a mid-ocean ridge, the rising magma cools
to form new oceanic lithosphere.
Transform Boundary
• The boundary that is created when two
tectonic plates slide past each other
horizontally.
– As the two tectonic plates slide past one
another, they are not smooth, they grind and
jerk as they slide, producing earthquakes.