Lesson:Lesson: Earths InteriorCan we explore Can we explore inside earth?inside earth?

The extreme temperature and pressure conditions inside of Earth’s interior prevent direct exploration by geologist.

What is a What is a geologist?geologist?

Scientist who study the origin, history and structure of the Earth.

How do How do geologist study geologist study earth’s interior?earth’s interior?

Geologist have used two main types of evidence to learn about earths interior: direct evidence from rock samples and indirect evidence from seismic waves.

What are seismic What are seismic waves?waves?

Vibrations that travel through earth. Using the data from seismic waves – the speed that they travel and the paths that they take, geologists have learned that the earth is made up of several layers.

What are the What are the layers?layers?

From outermost to innermost the layers are the crust, mantle and the core. Each layer varies greatly in size, composition, temperature and pressure.

What is the What is the crust?crust?

This is the layer of solid rock that forms the earth’s outer skin. It includes both dry land and ocean floor. The crust is the thickest under mountains and thinnest at the ocean floor. Oceanic crust consists of rocks such as basalt. Continental crust consists of rock such as granite.

The Crust

Earth’s hard outer Earth’s hard outer shellshell

Light and brittleLight and brittle It is cooler and It is cooler and

more rigid than the more rigid than the core and mantlecore and mantle

What is the mantle?

The layer of hot, solid rock beneath the crust. This is also where magma resides. This portion of earth’s interior is divided into layers based on physical characteristics.

What are the layers of the mantle?

The lithosphere, asthenosphere and lower mantle.

Lithosphere This is the uppermost part of the mantle and is similar (rigid/solid) to the crust.

Asthenosphere

This part of the mantle is somewhat soft and can bend. Although it is softer than the lithosphere, it is still solid.

Lower Mantle Located below the asthenosphere this portion of the mantle is solid all of the way to the core.

The MantleThe Mantle Thick shell of rock Thick shell of rock

surrounding the surrounding the outer coreouter core

Part of the mantle Part of the mantle is flexible, allowing is flexible, allowing it to bendit to bend

Makes up most of Makes up most of the Earth’s massthe Earth’s mass

Layers of the MantleLayers of the Mantle

What is the core?

This is the inner most layer of the earth. Composed of the metals iron and nickel. Contains an outer portion and an inner portion.

Outer core This is a layer of liquid (molten) metal that surrounds the inner core.

Inner core Made up of a dense ball of solid metal. Extreme pressure squeezes the atoms of iron and nickel so much that they cannot spread out and become liquid.

The Earth’s CoreThe Earth’s Core

The core is at The core is at the center of the center of the Earththe Earth

The center is The center is solid solid

The outer layer The outer layer is so hot it is is so hot it is moltenmolten

Why is the inside of the earth hot?

It is hot as a result of the heat left over from the formation of the planet. Also, the interior is further heated from the release of energy from radioactive substances inside the earth.

Summary Questions1.1. Label the picture to the right.Label the picture to the right.

2.2. What is the main type of rock in the oceanic What is the main type of rock in the oceanic crust?crust?

3.3. What are the layers of the mantle from top to What are the layers of the mantle from top to bottom?bottom?

4.4. What is the main difference between the outer What is the main difference between the outer core and inner core?core and inner core?

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Summary Answers1.1. SEE BELOW.SEE BELOW.

2.2. The main type of rock in the oceanic crust is The main type of rock in the oceanic crust is basalt.basalt.

3.3. The layers from outside to inside are the The layers from outside to inside are the lithosphere, asthenosphere and lower mantle.lithosphere, asthenosphere and lower mantle.

4.4. The outer core has the characteristics of a The outer core has the characteristics of a liquid and the inner core is solid.liquid and the inner core is solid.

INNER COREINNER CORE

MANTLEMANTLE

OUTER COREOUTER CORE

CRUSTCRUST