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Quarter 2 Earth's Interior
Concepts Cards fore Earth's Interior Sci 8th Quarter 2
10
Science
8th Grade
11/01/2017

Additional Science Flashcards

 


 

Cards

Term

 

 

Earth's Layers by Composition

Definition

Outward to Inward Order:

 

- Crust - Mostly Oxygen (Least Dense)

- Mantle - Mostly Magnesium

- Core - Mostly Iron (Most Dense)

Term

 

 

Earth's Crust

Definition

 

Outer Layer - 2 Types

 

Continental - Thicker, less dense

Oceanic - Thinner, more dense

Term

 

 

 

Earth's Layers by Physical Properties

Definition

 

 

Lithosphere - Outermost shell, Rigid, will break under pressure

 

Asthenosphere - Below the lithosphere, able to flow

 

Core - Center of Earth, hot temperatures

Term

 

Theory of Continental Drift

Definition

 

 

Proposed by Alfred Wegener

 

The continents were once joined in a super land mass called Pangaea that broke apart in to separate pieces and drifted over time to their present day locations.

Term

 

 

Evidence for Continental Drift

Definition
  1. Shape of Continents - Edges of continents look as if they could fit together like puzzle pieces. Ex. South America and Africa.
  2. Fossil Evidence - Mesosaurus - reptile that swam in fresh water, found on separate continents.  Could not have swam across the ocean.
  3. Mountain Chains - Identical mountains on separate continents that make a continuous mountain chain when put back together as part of Pangaea.
  4. Climate - Coal in Pennsylvania is shows PA was once tropical.  Must have been closer to the equator when it was part of Pangaea.
Term

 

 

Missing Evidence for Theory of Continental Drift

Definition

 

 

The Theory of Continental Drift was not accepted because Wegener could not explain HOW the continents moved.

Term

 

 

New discovery to help prove the Theory of Continental Drift

Definition

 

 

Mid Atlantic Ridge

 

A mountain chain on the sea floor in the middle of the Atlantic Ocean

 

 

Term

 

 

Sea-Floor Spreading

Definition

 

Sea Floor Spreading occurs Mid Atlantic Ridge

 

Heat from the CORE causes the ASTHENOSPHERE to expand, become less dense and rise.  As it moves away from the core it cools, becomes more dense and sinks.

 

This circulation (called convection) causes the LITHOSPHERE to pull apart at the surface.

 

The lithosphere (sea floor) is young and hot in temperature at the ridge and gets older and colder moving away from the ridge on both sides.

 

 

Term

 

 

Convection

Definition

 

Circulation that occurs in liquids or gases when a change in temperature and density causes circulation.

 

Happening in asthenosphere as a result of heat from the core.  Causes the lithosphere to pull apart - Sea Floor Spreading.

Term

 

 

Density

Definition

 

A measure of how tightly packed atoms and molecules are in a substance.

 

Substances will arrange themselves according to density.

 

Ex: More dense elements became the core, less dense elements became the crust.

 

 

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