Unit 7: Lesson 4: Earth's Layered Structure Q&A

Why is the inner core solid?

because it is under extreme pressure and is compressed into a solid as a result

Describe Earth's layers based on composition.

Based on composition, Earth is made up of the rocky crust, the mantle (made of rock-forming materials), and the metallic, iron-nickel core.

Why are meteorites considered important clues to the composition of Earth's interior?

Meteorites are thought to be made of the same material from which Earth was formed. Therefore, when they are found, they can give us an indication of the composition of the interior of Earth.

What evidence led scientists to conclude that Earth's outer core is liquid?

Scientists studied the different paths that P waves and S waves take inside Earth to determine the nature of Earth's core. P waves bent in a pattern indicating the existence of a boundary between the core and the mantle. The fact that S waves did not travel through the outer core indicated that the outer core is liquid.

What is the Moho?

The Moho is the boundary between the crust and the mantle.

Compare the physical properties of the asthenosphere and the lithosphere.

The lithosphere is a cool, rigid shell formed from the crust and upper mantle. On average it is 100 km thick. The asthenosphere is a soft, weak layer that experiences the conditions needed to produce a small amount of melting.

List Earth's layers based on physical properties, and their characteristics, in order from Earth's center to the surface.

inner core, outer core, lower mantle, asthenosphere, lithosphere (upper mantle and crust)