Structure & Composition of the Earth

4.a. Compare & contrast the lithosphere & the asthenosphere. (DOK 1)• Composition, density, & location

of continental crust & oceanic crust

• Physical nature of the lithosphere with the asthenosphere

• How the lithosphere responds to tectonic forces

BELLWORK 1/26Sean is studying the advantages of selective breeding in plants. He made the following list of possible advantages:1) Can produce corn that attracts grasshoppers2) Can develop grass that can grow with less water3) Can develop wheat that can grow in different types of soil 4) Can produce oranges that are not affected by freezing temperaturesWhich items on the list provide logical arguments in favor of selective breeding?A. 1, 2, 3B. 2, 3, 4C. 2, 4D. 3, 4

THE LAYERS OF THE EARTH• Order of the Earth’s interior from the surface to

the center:1. Crust2. Mantle3. Outer core4. Inner core

THE CRUST

• This is the layer you live on• The crust is the most widely studied &

understood layer of the Earth• Like the skin of an apple

THE CRUST

• Very thin in comparison to the other 3 layers of the Earth• 3-5 miles thick under the ocean• Oceanic crust• Thinnest part of the crust is under the ocean

• About 25 miles thick under the continents• Continental crust• Thickest part of the crust is under mountain ranges

THE CRUST

• Broken into many pieces called plates• The plates “float” on the soft, plastic mantle

that is very hot!• Temperatures range from atmospheric

temperature near the surface to 1600 degrees Fahrenheit near the mantle• Thinnest layer of the Earth

THE CRUST

• Composed to 2 basic rock types:1. Basalt• Volcanic lava rock• Oceanic crust

2. Granite • Continental crust• Basalt rock is much denser & heavier than granite

THE LITHOSPHERE

• Located in the crust & the upper layer of the mantle• Rigid & brittle rock

THE ASTHENOSPHERE

• Just below the lithosphere• Located in the upper part of the mantle• Plastic & flowing• Moves the plates of the Earth

THE MANTLE

• Located under the crust• Largest layer• 1800 miles thick• Very hot & dense rock• Contains the asthenosphere & part of the

lithosphere

THE MANTLE• Layers of rock flow like asphalt under a heavy weight• Due to the great temperature differences from the bottom to the

top of the mantle• Movement of the mantle is the reason the plates of the

Earth move• The Asthenosphere

• Temperature near the top of the mantle: 1600°F• Temperature near the bottom of the mantle: 4000°F

THE OUTER CORE

• Temperatures starting at 4000°F• So hot that the metals in it are all in the liquid

state• Located 1800 miles beneath the crust• 1400 miles thick• Composed of 2 metals:

1. Nickel 2. Iron

THE INNER CORE

• Temperatures & pressures are so great that the metals are squeezed together and are not able to move about like a liquid• Forced to vibrate in place as a solid• Begins about 4000 miles beneath the crust• 800 miles thick• Temperatures reach 9000°F• Pressures are 45 million pounds per square inch• This is 3 million times the air pressure at sea level

FACTS ABOUT THE INNER & OUTER CORE

• The inner core -- combined with the outer core -- provide the magnetic field that surrounds the earth.• The spin of the earth causes a rotation of the

inner core. • The spin of the liquid outer core around the

mostly-iron inner core creates the magnetic field.

EARTH’S FORMATION & COMPOSITION

• Many geologist believe that as the Earth cooled, the heavier, denser materials sank to the center and the lighter materials rose to the top• Scientists are concerned that the increasing

levels of CO2 in the atmosphere could cause overall heating of the Earth’s interior• Geologists drill through the oceanic crust in their

attempt to reach the mantle because it is thinner than the continental crust

EARTH’S FORMATION & COMPOSITION

• As Earth’s depth increases, the density, temperature & pressure also increases

DEFORMATION OF EARTH’S CRUST

• Earth’s crust can be deformed through:• Faulting – a break or crack along which rocks move• Folding – a bend in a rock

Faulting Folding

WRITE DOWN THESE QUESTIONS….1. What are the 4 layers of

the Earth?2. What 2 types of rock is

the crust composed of?3. Which type of rock is

found in the continental crust?

4. Which type of rock is found in the oceanic crust?

5. What part of the Earth is classified as rigid and brittle?

6. How thick is the mantle?7. What are the 2 parts of

the core?8. What temperature does

the inner core reach?9. What factors increase as

the Earth’s depth increases?

10. What are the two ways the Earth’s crust can become deformed?

11. Describe the outer core.

12. What layer of the Earth is the thickest?

13. What layer of the Earth is the thinnest?

14. What part of the crust is the thickest?

15. What part of the crust is the thinnest?

16. What part of the Earth is classified as plastic and flowing?

17. What is faulting?18. What is folding?19. What state is the inner

core in?20. What layer of the Earth

is like the skin of an apple?

BELLWORK 1/27

Tinea pedis is a disease caused by a fungus. It affects mainly external body parts and not internal systems.Which of these could be a symptom of tinea pedis?F. Difficulty breathingG. Pain in the intestinesH. Headaches and dizzinessJ. Swollen and itching skin

CLASSWORK

• Complete Layers of the Earth worksheet packet.• If you finish before the bell rings, you may read a

book or work on something from another class.

BELLWORK 1/28

• List the layers of the Earth in order from the surface to the interior. • Study your notes!