Day 1. Earth’s Structure Earth is composed of four layers: 1.Crust (outer layer): Thin and nearly...

Day 1

Earth’s Structure

• Earth is composed of four layers:

1. Crust (outer layer): Thin and nearly all solid rock. Thickness of about 5-50 miles.

2. Mantle: Thickest layer, about 2,000 miles thick.3. Outer Core: about 1,400 miles thick- it is all liquid.4. Inner Core: Solid (due to high pressure). 750 miles

thick.

Think of a Peach…

A peach can be used as a model of the

earth.

The skin= the crust.The flesh= the mantle.

The pit= core.

Proposed the Theory of “continental drift” in 1912

Alfred Wegener was curious. He looked at the shapes of continents and the locations

of fossils to understand how continents were once connected.

When they are connected, they form a supercontinent. Alfred Wegener named this

large continent “Pangaea.” .

Alfred Wegener

Alfred Wegener

Over time, Pangaea split apart. Continents moved away from each other as the oceans between them grew wider. He called

his theory, or idea, “Continental Drift.”

What is the theory of continental drift?

• The idea that the continents were once all joined together in one super-continent called Pangaea and

slowly moved to their current positions

Animated Plate Tectonic Reconstruction

Evidence of Pangaea

• Continents look like they could be part of a giant jigsaw puzzle.• Plant and animal fossils found on the coastlines of different continents.• Measurements of movement• Rock layer sequences

Pangaea Demo

Brainpop

Day 2

What is Plate Tectonics?• The Earth's thin outer shell is broken into big

pieces called tectonic plates. • Plates Plates are slabs are slabs of Earth’s crust and upper

mantle. These plates fit together like a puzzle, but they're not stuck in one place. They are floating on the Earth's mantle (a really thick layer of hot flowing rock).

The Theory of Plate Tectonics• The surface of the Earth is composed of about a

dozen major rigid, moving crustal plates

What Causes the Plates to Move?

• Convection- hot magma rises, cool magma sinks (like a lava lamp)

• The flow of the mantle causes the plates to move in different directions.

• Plates move around on top of the mantle like

rafts.

• When the edges of plates meet, three things can happen:

• Divergent Boundaries: Group 1• Convergent Boundaries: Group 2• Sliding Boundaries: Group 3

In Your Group…Turn to page 209 in your textbook.

Find…1. Characteristics of your boundary.2. How it moves.3. What kind of land formation occurs due to your

boundary.• You will teach the class about your boundary.• You will also teach your classmates how your

boundary moves, so come up with a movement to show how it moves!

• Plates move away from each other.• Melted rock rises up between the plates and forms new crust• Usually happens in the middle of the ocean floor.• Forms volcanoes and new crust

Divergent Boundary:

Examples:

Mid-Atlantic Ridge

Iceland Ridge

Divergent (2nd flap)

• Forms…• Volcanoes and New Crust

Example: Mid-Atlantic Ridge

Convergent boundary occurs when two plates converge, or move toward each other.

They eventually collide.

One plate may ride up over the other, while the other plate is pushed under the surface.

Convergent Boundary

There are three types of

convergent boundaries.

Continental-Continental BoundaryForms Mountains

Examples

The Himalayas

The Appalachians

Oceanic-Oceanic Boundary

• Creates trenches (deep valleys)• Forms volcanoes • Ex) Aleutian Islands (Alaska)

Examples

Mt. Augustine, Alaska

Aleutian Islands, Alaska

Oceanic-Continental Boundary

• Oceanic plate pushes down because it is more dense

• Creates

mountain ranges

Examples…

• Andes mountains

Plates slide past each other in opposite directions.

Forms EARTHQUAKES

Sliding Boundaries

Examples

San Andreas Fault, CA

Fault line in Tennessee

Animations