Chapter 7 Section 1 Inside the Earth

Compositional Layers of the Earth (Brown) (Gray/green)

Composition of the Earth: The Earth is divided into 3 compositional layers: Core: iron, nickel Mantle: magnesium, iron, aluminum, silicon, oxygen Crust: oxygen, silicon, aluminum, iron, calcium, & magnesium Crust and mantle are not very dense. Core is denser than the crust & mantle.

Compositional layers of Earth

CRUST The outermost layer 2 types of crust 5-100 km thick Thinnest layer 2 types of crust Continental- thick Oceanic-thin

MANTLE 2900 km thick Layer between the crust and core Thicker than crust Contains most of Earth’s mass Scientists study the mantle by looking at the composition of magma. Magma from volcanoes gives scientists clues about the composition of the mantle.

How scientists see the mantle Volcanic eruption of Mt. Etna in Sicily

CORE Innermost layer, below mantle to center of Earth Made mostly of iron and nickel Divided into two parts Inner core—solid Outer core—liquid

Physical Properties of Earth: How the layers respond to heat and pressure Earth divided into 5 physical (mechanical) layers: Lithosphere Asthenosphere Mesosphere Outer Core Inner Core

Lithosphere Outer layer of Earth Made of crust & rigid, upper mantle (asthenosphere) Divided into pieces called tectonic, or continental plates Continental plates drift slowly—a few centimeters a year—on top of the mantle

Asthenosphere Layer below lithosphere Pieces of lithosphere (tectonic plates) move along this layer Made of solid rock, soft, plastic-like layer of the mantle

Mesosphere Below the asthenosphere Strong lower part of mantle Extends to the Earth’s core

Outer Core Liquid layer of Earth’s core Surrounds inner core

Inner Core Solid dense center

Quiz 1. What are the three compositional layers of the Earth? 2. What are the physical layers of the Earth? 3. Is the mantle solid or liquid? 4. What physical and compositional layers of the Earth do you live on?

Quiz Answers 1. What are the three compositional layers of the Earth? Crust, Mantle, and Core (CMC) 2. What are the physical layers of the Earth? Lithosphere, Asthenosphere, Mesosphere, Outer Core, and Inner Core 3. Is the mantle solid or liquid? Liquid that can be forced to act as a solid 4. What physical and compositional layers of the Earth do you live on? Physical: lithosphere Compositional: Crust