Chapter 12 Section 3Earth’s Interior

Chapter 12 Section 3 – What You’ll Learn - page 370Before you read - write the reading’s objectives in this space:1 – _____________________________________________________________________________________________________________________________________________

2 – _____________________________________________________________________________________________________________________________________________________________________________________________

Chapter 12 Section 3 – What You’ll Learn - page 363Before you read - write the reading’s objectives in this space:1 – Explain how geologists infer the structure of Earth’s deep interior.

2 – Describe Earth’s internal structure and composition.

How do scientists learn about Earth’s interior?Use seismic waves to gather data about Earth’s interior – kind of like a sonogram on humans!

Label the diagramto the right with the general name and thickness:

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Earth’s Interior Video 1.5 min1

How do scientists learn about Earth’s interior?Use seismic waves to gather data about Earth’s interior – kind of like a sonogram on humans!

Label the diagramto the right with the general name and thickness:

Inner core 1220 km

Outer core 2250 km

Mantle 2900 km

Asthenoshphere200 km

5 Lithosphere 100 km

Earth’s Interior Video 1.5 min

Recall what is refraction?___________________________________________________________________________________________________What is a discontinuity?_________________________________________________________________________________________________________________________________

Andrija Mohorovičić was the first in the world to establish, on the basis of seismic waves, a surface of velocity discontinuity that separates the crust of the Earth from the mantle and which was named the Mohorovičić Discontinuity, also known as the Moho, in his honor. 2

Recall what is refraction?The bending of waves due to a change in density.

What is a discontinuity?A boundary that marks a density change between Earth’s layers. The Mohorovičić discontinuity separates Earth’s crust from the mantel.Andrija Mohorovičić was the first in the

world to establish, on the basis of seismic waves, a surface of velocity discontinuity that separates the crust of the Earth from the mantle and which was named the Mohorovičić Discontinuity, also known as the Moho, in his honor.

What is the shadow zone?____________________________________________________________________________________________________________________________________________________________________________________________________________________________________ 3

What is the shadow zone?

A dead zone between 105 and 140 degrees from the focus of an earthquake, little or no seismic waves can be detected.

This is because primary waves (P-waves) are refracted by the Earth's core and secondary waves (S-waves) are stopped by the core.

Shadow Zones

Earth’s InteriorEarth’s Interior

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Composition of Earth’s Layers describe the following:The crust and uppermost mantle (The lithosphere) _______ ____________________________________________________________________________________The asthenosphere _____________________________ ____________________________________________________________________________________Mantle below the asthenosphere __________________ __________________________________________The cores ___________________________________ ____________________________________________________________________________________

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Composition of Earth’s Layers describe the following:The crust and uppermost mantle (The lithosphere) are made of rocky material—mostly silicates.

The asthenosphere is a weaker, plastic like layer upon which Earth’s lithospheric plates move.

Mantle below the asthenosphere also is composed of silicates.

The cores are made mostly of metallic material iron and nickel.

How do astronomers think the Earth formed? ______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ 5

How do astronomers think the Earth formed? From meteor-like material forced together by gravity and melted. The densest of this material settled toward the core and the lower density materials settled outward.

Section CheckSection Check

Question 1

What is Earth’s core made of?___________________________________________________________________________________________________________________

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Section CheckSection Check

Question 1

What is Earth’s core made of?

Answer

Earth’s core is primarily made of metallic material such as iron and nickel.

Section CheckSection CheckQuestion 2

Earth’s internal layers become _______ with depth.

A. coolerB. darkerC. denserD. lighter

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Section CheckSection CheckQuestion 2

Earth’s internal layers become _______ with depth.

A. coolerB. darkerC. denserD. lighter

The answer is C.

Answer

Section CheckSection Check

Question 3

What can’t S-waves penetrate the liquid outer core?________________________________________________________________________________________________________________________________________________________________

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Section CheckSection Check

Question 3

What can’t S-waves penetrate the liquid outer core?

Answer

S-waves only travel through solids. This suggests that the outer core is in a liquid state.