Earth’s Layers: Changing Earth homework #1 Student Name: ___________________Use this text and the work from class to answer the questions about the Earth’s layers.

Scientists know more about Earth’s crust than they do about the mantle or core. The crust is the thin, brittle outer shell of the planet. It is made of solid rock. The crust under the oceans is called oceanic crust. The crust of the continents is called continental crust. The two parts of the crust have several differences.

• Oceanic crust is made of basalt, an igneous rock. It formed when lava flowed onto the ocean floor and hardened into rock. The oceanic crust is denser than the continental crust but thinner, ranging from 5 to 12 kilometers in thickness. Thick layers of mud cover much of the ocean floor.

• Continental crust is made of all three types of rock: sedimentary, igneous, and metamorphic. It is less dense than oceanic crust, so it rises higher above the mantle than oceanic crust. Continental crust is much thicker than oceanic crust, averaging 35 kilometers in thickness.

1. Describe Earth’s crust.

2. Why do you think scientists know more about Earth’s crust than Earth’s other layers?

3. Compare and contrast oceanic crust and continental crust.

Match each definition with the correct term. Definitions_____ 1. rock from space that strikes Earth_____ 2. Earth’s middle layer_____ 3. bendable layer of Earth in the upper mantle that lies beneath the lithosphere_____ 4. Earth’s outer layer_____ 5. brittle layer of Earth consisting of the crust and uppermost mantle_____ 6. liquid part of Earth’s dense metallic center_____ 7. solid part of Earth’s dense metallic center

Terms

a. crustb. asthenospherec. outer cored. mantlee. meteoritef. lithosphereg. inner core

BothContinental Crust Oceanic Crust

Earth’s Layers: Changing Earth homework #1 Student Name: ___________________Use this text and the work from class to answer the questions about the Earth’s layers.

Lithosphere - The lithosphere is composed of both the crust and the portion of the upper mantle that behaves as a brittle, rigid solid. The lithosphere is the outermost mechanical layer, which behaves as a brittle, rigid solid. The lithosphere is about 100 kilometers thick. How are crust and lithosphere different from each other?The definition of the lithosphere is based on how Earth materials behave, so it includes the crust and the uppermost mantle, which are both brittle. Since it is rigid and brittle, when stresses act on the lithosphere, it breaks. This is what we experience as an earthquake.Although we sometimes refer to Earth's plates as being plates of crust, the plates are actually made of lithosphere.

Asthenosphere - The asthenosphere is solid upper mantle material that is so hot that it behaves plastically and can flow. The lithosphere rides on the asthenosphere.

1. Where is the lithosphere?

2. What layers does it include?

3. What is the asthenosphere?

4. How do the lithosphere and asthenosphere differ?

Draw arrows to show the location of each layer and match the composition to each layer.