Page 76 - Science Course 2 (Book 2)

Mo10-L1b: What is the Structure of the Geosphere?

What is the Structure of the Let’s Begin
Mo10-L1b Geosphere?

KEY CONCEPTS: Structure of the Geosphere
1. Why does the geosphere have a layered structure?
The geosphere has three main layers: the crust, the
mantle, and the core.
Vocabulary A-Z The densest layer of the geosphere is the center, or
Let us learn some vocabulary core, and the least dense layer is the outer crust.

Crust

Mantle

Outer Core

Inner Core

crust Upper Mantle
the brittle, rocky outer layer of Earth. • Solid 670 km
• Magnesium and iron silicates below surface
• Density - 3.9g/cm³
mantle Lower Mantle
the thick middle layer in the solid part of Earth. • Solid 2,900 km
• Magnesium and iron silicates below surface
• Density - 5.0g/cm³
core
Outer Core
the dense, metallic center of Earth.
• Liquid 5,150 km
• Iron below surface
lithosphere • Density - 11.1g/cm³
the rigid outermost layer of Earth that includes the Inner Core 6,370 km
uppermost mantle and crust. • Liquid from surface to
• Iron center
asthenosphere • Density - 13.0g/cm³
the partially melted portion on the mantle below the Scientists hypothesize Earth’s layers formed early in
lithosphere. the planet’s history.

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