Layers of the Earth

• Describe Earth's layers: the crust, mantle, and core based on their composition.

• Differentiate between the lithosphere and asthenosphere based on their physical properties.

• Identify and define Earth's major spheres: the atmosphere, hydrosphere, and biosphere.

• Explain how the different layers and spheres of the Earth interact with one another.

Key Vocabulary

Crust

The outermost solid layer of the Earth, which makes up less than 1% of the planet's mass.

Mantle

The hot rock layer between the crust and core, representing about 68% of the Earth's total mass.

Lithosphere

The rigid outer part of Earth, consisting of the crust and the solid upper portion of the mantle.

Asthenosphere

The partially molten upper mantle that behaves plastically and can flow over geological time.

Atmosphere

The thin layer of gases, mostly nitrogen and oxygen, that completely surrounds our entire planet.

Hydrosphere

The combined mass of all the water that is found on, under, and over the surface of Earth.

Earth's Layers by Composition

• The crust is the outermost layer, making up less than 1% of Earth's mass.

• It has two types: oceanic crust under the oceans and continental crust for continents.

• The mantle is a hot layer of rock, making up 68% of Earth's mass.

• The core is the dense, iron metal center, making up 31% of Earth's mass.

Earth's Layers by Mechanical Properties

• The lithosphere is made of the crust and rigid upper mantle.

• ​It is a brittle, rigid solid that includes Earth’s continents.

• The asthenosphere is a partially molten layer below the lithosphere.

• It behaves plastically, meaning it can slowly flow and move.

Earth's Major Spheres

• Earth's surface has several spheres with all its gases, water, and life.

• The atmosphere is the layer of air surrounding the entire planet.

• The hydrosphere has all the water, and the biosphere has all living things.

• All of Earth's spheres are interconnected and constantly interact with one another.

• Earth has layers based on composition and mechanical properties.

• The crust is the thin outer layer; the core is the dense iron center.

• The lithosphere is a rigid layer, while the asthenosphere is a flowing layer.

• Earth's spheres interact, causing continuous changes to the Earth's surface.