Section 4.1 Vocabulary to knowCrust Mantle Core Lithosphere Continental crust Oceanic crust Asthenosphere Mesosphere Outer core Inner core Radioactivity

Earth’s interior… Made up of: –Crust, mantle, and core

Crust Crust- –Outermost and thinnest layer of Earth. –Relatively cool. Two types: –Oceanic crust Crust beneath ocean ( mi thick) More dense –Continental crust Crust beneath continents (12-25 mi thick) Less dense

In between the crust and mantle… sort of… Lithosphere- –The thin outer shell of the Earth. Consists of the crust and the rigid upper mantle. Asthenosphere- –Beneath lithosphere (in the mantle). Consists of slowly flowing solid rock.

This Sucks!

Mantle Mantle- –Layer of rock between Earth’s crust and core. –More dense than the crust (which is why it’s beneath it). –Makes up about 80% of Earth’s volume. –Outer mantle- Rocks mostly solid. –Inner mantle- Rocks easily deformed

Core Core- –Center of a planetary body. –Composed of iron (Fe) and Nickel (Ni). Two layers: –Outer core Liquid metal –Inner core Solid metal

Where is it the hottest? The Earth gets hotter as you go deeper! –Crust ( ~347 o F) –Mantle (~2280 o F) –Outer core (~7000 o F) So hot that the rocks actually melt! –Inner core (~10,800 o F) So hot that the rocks melt BUT so much pressure that they remain a solid!

Why is the Interior so hot? It contains radioactive isotopes. –Uranium, Thorium, and Potassium Their nuclei break up (decay) releasing energy as they become smaller nuclei. Earth is huge…so there is a lot of energy being released.

How to remember the 5 physical Structures of the Earth…in order Using the hand method

1 st Layer LITHOSPHERE

2 nd Layer ASTHENOSPHERE

3 rd Layer What would three scared foreigners say if they don’t speak english and are trapped under two of Earth’s physical structures? MESOSPHERE (ME SO FEAR)

4 TH Layer What was Lincoln know for saying? Four S CORE and 7 years ago. (Outer)

5 th Layer These guys are??? INNER

Section 4.2 and 4.3 Vocabulary to knowPlate tectonics Continental drift Alfred Weggener Pangaea Convection currents Subduction Sea-floor spreading Mid ocean ridge Rift valleys Trench Magnetic striping

PLATE TECTONICS Plate Tectonics- –theory that explains the formation and movement of earth’s plates Continental Drift- –Alfred Weggener’s theory that continents were once joined in a single supercontinent, which then broke into pieces that moved apart. –Move 0.4 to 6.3 in. per year

Continental Drift How could a fresh- water animal (Mesosaurus) be found on two continents that are separated by an ocean? Could it be…

Evidence of Continental Drift …Continental drift! –Many fossils matched up perfectly once the continents were put together. –The continents also fit together like puzzle pieces. –But how could continents move?

Scientists aren’t quite sure… …but they think it might be due to convection currents.  Water rises because it’s less dense… then cools and sinks as it becomes more dense.

Sea-floor Spreading Would you expect the middle of the ocean to be its deepest point? –Why or why not?

Ridges

At its peak, the mid-ocean ridge has a valley, also known as a rift…

What happens when plates run into plates? Mariana Trench  –Lowest point on Earth. 35,798 ft below sea level.  Mount Everest from space.  Highest point on Earth  29,028 ft above sea level.

Subduction

Trench- –as a plate sinks through a subduction zone, it bends forming a depression in the ocean floor. What is the deepest point in the ocean?

Subduction Sea-floor spreading- creates new oceanic crust at mid-ocean ridges. Subduction- destroys old oceanic crust at subduction zones.

Evidence

Magnetic striping –Tiny grains of magnetite in the rock of the ocean floor behave like little magnets. –Align with orientation of the Earth’s magnetic field. –Points north presently… Not always the case…