unit 5 – structure of the earth

1. What is the crust? 1. The crust is the outmost layer of the earth.

Is made of hard rocks contains silicon and

oxygen (silicates) and aluminum

5 km to 50 km thick

http://videos.howstuffworks.com/hsw/6222-mountain-building-earths-inner-crust-video.htm

2. What is the mantle?

2. The mantle is the middle layer of the earth contains lots of iron and magnesium silicates makes up 82% of earth’s volume and 68% of earth’s mass

3. What is the core? 3. The core is the innermost layer of the earth contains iron and nickel metalsvery dense makes up 16% ofearth’s volume and 32% of earth’s mass

http://videos.howstuffworks.com/science-channel/29142-100-greatest-discoveries-the-core-of-the-earth-video.htm

Core

Mantle

Crust

Core

Mantle

Crust

Chemical

Inner Core

Outer Core

Mesosphere

LithosphereAsthenosphere

Physical

4. What is the lithosphere?

4. The lithosphere is a cool, solid outer layer of the earth includes the crust and outer mantle 100 km thick floats on the plastic asthenosphere

5. What is the asthenosphere?

5. The asthensoshpere is a hot semi-liquid layer of the mantle just below the lithosphere. Is soft and flows.

6.What is the mesosphere?

6. The mesosphere is a solid layer of the inner mantle.

Pressure keeps rocks from melting.

7.What is the outer core?

7. The outer core is a liquid inner layer

Mostly liquid iron Thought to be the

source of the earth’s magnetic field.

8.What is the inner core?

8. The inner core is the innermost part of the earth.

4000oC – 4500oC

9. Who was Alfred Wegener

9. Around 1912, Wegener, a German geologist and astronomer, proposed that continents move

• Pangaea – supercontinent formed when all of earth’s landmasses were joined

• Scientists didn’t believe him for almost 50 years

10. What evidence supports Pangaea?

10. Fossils of same species on all continents Same rock formations across continents Ancient glaciers were in the tropics

11. When and how was the ocean floor mapped?

11. The ocean floor was mapped in the 1950s using sonar.

http://videos.howstuffworks.com/hsw/9068-discovering-math-measuring-distance-and-depth-video.htm

12. How does sea floor spreading occur?

12. Mid-ocean ridge is a huge crack where the hot mantle pushes upward.Crust is older as you move outward from the ridgeMagnetic field reverses

http://videos.howstuffworks.com/hsw/26560-earth-science-the-spreading-seafloor-video.htm

13. Describe plate tectonics

13. Lithosphere is divided into plates that constantly moveContinental Plates – lighter Oceanic Plates – heavier

http://videos.howstuffworks.com/hsw/8638-inside-the-earth-continental-drift-video.htm

14. What are divergent boundaries?

14. Divergent boundaries are plates that move apart.Examples:Mid-oceanic ridgeGreat Rift Valley in Africa

14. What are convergent boundaries?

14. Convergent plates occur when plates run into each other ( subduction zone)Examples:Oceanic to oceanic – JapanOceanic to continental – Andes Mountains in South AmericaContinental to continental – Himalayan Mountains in Asia

Oceanic to continental – Andes Mountains in South America

Continental to continental – Himalayan Mountains in Asia

15. What is a transform boundary?

15. In a transform boundary, plates slide in opposite directions. Example: San Andreas Fault, California