Download ESU-LT1-4

Chapter 2
Earth as a System
LT 1: I can describe the size and
shape of Earth
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Earth Basics
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Only known planet that has liquid water
Only known planet to support life
Third planet from the sun in our solar system
Formed 4.6 billion years ago
Made mostly of rock
71% of Earth’s surface is covered by a thin layer of
water called the global ocean
More Basics
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Earth is an oblate spheroid (flattened sphere)
Pole-to-Pole Circumference is 40,007 km
Equatorial Circumference is 40,074 km
Average diameter is 12,756 km
LT 2: I can describe the
compositional and structural layers
of Earth’s Interior
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Compositional Zones
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Crust: outmost zone; 1% of Earth’s mass
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Mantle: layer under the crust; denser than the crust
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Oceanic Crust: crust beneath the ocean; 5-10 km thick
Continental Crust: crust beneath land; 15-80 km thick; thickest
beneath mountain ranges
2900 km thick
Makes up 2/3 of Earth’s mass
Core: center of Earth; sphere with a radius of 3500 km; made
up of mostly iron and nickel; almost 1/3 of Earth’s mass
Structural Zones
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3 compositional zones are broken down into 5
structural zones
Lithosphere: solid outer layer of Earth that consists of
the crust and the rigid upper mantle
Asthenosphere: the solid, plastic layer of the mantle
beneath the lithosphere
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Made of mantle rock that flows very slowly, which allows the
tectonic plates to move on top of it
Mesosphere: the strong, lower part of the mantle
Outer Core: dense liquid, begins at a depth of 2900 km
Inner Core: dense rigid solid, begins at a depth of 5150
km
LT 3: I can identify the possible
source of Earth’s magnetic field.
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Two magnetic poles (North geomagnetic pole
and South geomagnetic pole)
Region of space affected by Earth’s magnetic
field is the magnetosphere
Source of magnetic field is believed to be the
liquid iron in Earth’s core
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Motions within the core create electric currents
which in turn create the magnetic field
LT 4: I can summarize Newton’s law
of gravitation
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Gravity: the force of attraction that exists
between all matter in the universe
Isaac Newton was first to explain
Law of Gravitation: the force of attraction
between any two objects depends on the
masses of the objects and distance between
the objects.
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The larger the masses, the closer together they are,
the greater the attraction.