Unit 4 Lesson 1 Earth’s Layers
Peeling the Layers
What is inside Earth?
• Earth is made of several layers.
• Each layer has its own characteristic properties.
• Scientists think about Earth’s layers in two ways—
in terms of chemical composition and in terms of
physical properties.
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Brain pop on earth’s layers
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Unit 4 Lesson 1 Earth’s Layers
What are Earth’s compositional layers?
• Earth can be divided into four layers based on
chemical composition: the crust, the mantle, and
the outer core and the inner core.
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Unit 4 Lesson 1 Earth’s Layers
What are Earth’s compositional layers?
• The outermost solid layer of Earth is the crust.
• There are two types of crust:
• A)continental and
• B) oceanic.
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Unit 4 Lesson 1 Earth’s Layers
What are Earth’s compositional layers?
• Both types of crust are made mostly of oxygen,
silicon, and aluminum. Crustal plates are made
up of crust and upper mantle.
• Oceanic crust is denser than continental crust
because it contains almost twice as much iron,
calcium, and magnesium.
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Unit 4 Lesson 1 Earth’s Layers
What are Earth’s compositional layers?
• The mantle is located between the crust and the
core. 30 km-2900 km thick; temp. over 1,000
degrees C.
• The mantle is a region of hot, slow-flowing solid
rock.
• The mantle contains more magnesium and less
aluminum and silicon than the crust.
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Unit 4 Lesson 1 Earth’s Layers
What are Earth’s compositional layers?
• Convection is the movement of matter that
results from differences in density caused by
variations in temperature.
• Convection in the mantle causes cooler rock to
sink and warmer rock to rise.
• This aids in moving the plates ( plate tectonics)
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11.6 km = 1 mile !
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The core extends from
The
The
Below mantle to center
of the earth.
The core is densest
layer and makes up
about 1/3 of the
earth’s mass.
Unit 4 Lesson 1 Earth’s Layers
What are Earth’s physical layers?
• Earth is also divided into layers based on physical
properties, such as whether the layer is solid or
liquid.
• The five physical layers are the lithosphere,
asthenosphere, mesosphere, outer core, and inner
core.
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Unit 4 Lesson 1 Earth’s Layers
What are Earth’s physical layers?
• The outermost, rigid layer of Earth is the
lithosphere.
• The lithosphere is made of the crust and the rigid,
upper part of the mantle. It is about 100 km
thick. ( about 63 miles )
• The lithosphere is divided into pieces called
tectonic plates.
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Unit 4 Lesson 1 Earth’s Layers
What are Earth’s physical layers?
• The asthenosphere is the layer of weak or soft
mantle made of solid rock that moves very slowly.
• The asthenosphere is located below the
lithosphere and is often described as “plastic like”
• Tectonic plates move on top of the asthenosphere.
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Unit 4 Lesson 1 Earth’s Layers
What are Earth’s physical layers?
• The strong, lower part of the mantle is called the
mesosphere.
• Rock in the mesosphere flows more slowly
than rock in the asthenosphere.
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Unit 4 Lesson 1 Earth’s Layers
What are Earth’s physical layers?
• The outer core is the liquid layer of Earth’s core.
• The outer core lies beneath the mantle and
surrounds the inner core. About 3700 degrees C
• Mostly nickel and Iron– this liquid layer
contributes to the Earth’s magnetic field.
• The magnetic field of the Earth protects the Earth
from the Sun’s dangerous radiation
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https://www.khanacademy.org/science/cosmol
ogy-and-astronomy/earth-history-topic/platetechtonics/v/compositional-and-mechanicallayers-of-the-earth
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cience/cosmology-andastronomy/earth-historytopic/platetechtonics/v/compositional-and
Unit 4 Lesson 1 Earth’s Layers
What are Earth’s physical layers?
• The inner core is the solid, dense center of our
planet. Thickness: 5100 km to 6400 km ; temp.
is about 4, 300 – 5000 degrees C
• The inner core extends from the bottom of the
outer core to the center of Earth. Almost all
IRON!
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