what features of the earth do you see in this picture??

What features of the earth do you see in this

picture??

What is the burning rock called? Where does it come

from?

What causes such an eruption of lava from the earth??

From this image showing lava flowing from dry land into the ocean, what do you think

this chapter might be about??

Plate TectonicsChapter 5

Section 1 Drifting Continents

Objectives:› Describe how the continents moved

over the past 250 million years› Explain the evidence supporting

continental drift› Make a model of the supercontinent

Pangaea

Skills Warm-up

A puzzling World› Look at the map on the next slide and

study the shapes of the continents closely.

› What do you notice about the shapes of the continents on the opposite sides of the Atlantic Ocean?

Drifting Continents

Hundreds of years ago, the 1st _________ ________ were made

People noticed that some of the continents could ___________ like ________ _________

But if the continents were once joined, how could they have moved??

Theory of Continental Drift

During the 1800’s, scientists studying ______ ____ ______ found evidence that seemed to support the idea of ________ ____________

What evidence do you think this was?

Alfred Wegener (1880-1930)

German _____________ Gathered evidence

and proposed the ___ ______ ___ _________ __________

Claimed that all landmasses were once joined as a supercontinent – _____________

Theory not accepted until the 1950’s

Activity

Pangaea Worksheet Page 20 of Integrated Resource Book

The Breakup of Pangaea

Scientists have collected large amounts of _______ on how the continents _______

They have pieced together a ________ of the continents

The Breakup of Pangaea

______ ________ ____ ___________________

All of the continents were part of one ___________________ called Pangaea

The Breakup of Pangaea

Step 1 ______ ________years

ago (Mesozoic Era) Pangaea began to

_______ ___________ across its __________

2 major continents formed› __________________

(south)› __________________

(north)

The Breakup of Pangaea

Step 2 _____ _________

years ago _________________

began to break up into _________ pieces that would become› _______________› _______________› _______________› _______________› _______________

The Breakup of Pangaea

Step 3 ____ _________ years ago _________ breaks apart

forming landmasses that would become› ________________› ________________› ________________

_________, which has been drifting north for 100 million years, collides with ________

The Breakup of Pangaea

Step 4

Continents as they _________ _______

Do you think the continents will keep moving around??

Activity

Watch movie “Plate Tectonics – Our Restless Planet” from Discovery Education

Write down 10 things you learned from movie and hand in at end of class

Activity

Continental Drift Lab Page 29 of Laboratory Manual

Evidence for Continental Drift

Scientists have collected a lot of evidence supporting 2 related conclusions› 1.____________________

_______________________________________________________________

› 2. ____________________________________________________________________________________

Fossil Evidence

A _________ kind of organism or species appears on earth only in ______ _______and then _________ _____

Animals that swim and plants with windblown seeds can spread _________ ___ _________

But, _______ _________ can only spread out across land

Fossil Evidence ___________________

found fossils of an ancient fernlike plant called _____________ in› _________________› _________________› _________________› _________________› _________________

What can they infer from this??

Fossil Evidence

That all of these continents were ________________ at one time!!

Fossil Evidence

Fossils of several other species have a similar pattern

None of these organisms could have __________ ___ _____________

How could they end up on different continents??

Fossil Evidence Fossils of _____________,

a Triassic land reptile, were found in Africa, Antarctica, and India

Fossils of _____________, a freshwater reptile, were found in Africa and South America

Fossils of _____________, a Triassic land reptile, were found in South America and Africa

Fossil Evidence

Fossil evidence also shows that the continents have ___________ over the earth’s surface

Fossils found in _____________ show it once was home to vast ______ _________ and _________ full of plant and animal life

How could this be??

Rock Evidence There are many

___________ between the rocks and landforms of _______ and ______ _________

If the 2 continents are fitted together, their __________ _______ ______ ____

Also, the mountain’s rocks are similar in _____ _____ _______

Were the 2 mountain ranges once one??

Activity

Watch movie “Fossils – Windows into the Past” from Discovery education”

Write down 10 fossil facts from movie and hand in at the end of class.

Skills Warm-up

Is it True??› Recall a time when someone told

you that something you believed to be true, really wasn’t.

› How did you react?› Was your reaction similar to the way

scientists reacted to Wegener’s ideas?

Evidence from Ancient Glaciers

______ are huge masses of ______ that move ________ over land

During the ice ages, glaciers spread _________ _____ _____ _________

Glaciers always move __________ _____________

Evidence from Ancient Glaciers Rocks that show

evidence of glaciers at the end of the _________ ______ were found in› _________________› _________________› _________________› _________________

How could this be if it is usually hot in these places??

Evidence from Ancient Glaciers

Rocks can also show the ________________ in which glaciers ________________

Ice age glaciers seemed to travel __________ from present day ________

This doesn’t make sense!!

Evidence from Ancient Glaciers

Can only be explained if the following continents were once part of the _______ _________› _________________› _________________› _________________› _________________› _________________

Activity - Answer the following questions on a sheet of paper and turn in by the end of class

1. Which present day continents were once part of Gondwanaland?

2. List 2 types of evidence that support the idea of continental drift.

3. What will happen to the size of the Atlantic Ocean in the next 50 million years?

4. If you found evidence of glaciers in areas with warm climates, what would you conclude?

5. How does evidence of glacier movement support the idea of a single landmass?

Section 2 Theory of PlateTectonics

Objectives:› Describe the process of sea-floor

spreading› Identify different types of plate boundaries› Explain what happens when plates come

together› Infer from observation of a large surface

feature what kind of plate boundary produced it

Skills Warm-up

Moving Plates› The word plate means “a smooth,

flat, thin piece of material”› The word tectonic means “having a

strong and widespread impact”› Does this give you enough

information to get a good idea of what plate tectonics is all about?

Ocean-Floor Discoveries

1950’s – Scientists finally got the tool they needed to study the ocean floor

_______ __________ – could bounce ________ waves off the ocean bottom › if a sound wave bounced

back _________, the ocean floor was ___________

› if a sound wave took longer to bounce back, the ocean floor was __________

This allowed them to make a map of the ______________ of the ocean floor

Ocean-Floor Discoveries Scientists discovered

long, underwater ____________________

The ranges formed one long __________ snaking through all of the oceans (baseball seams)

This ________________ had a deep valley running the length of its crest

Ocean-Floor Discoveries

Scientists found rocks from the ocean bottom were _________ than the rocks in the ____________

Also the rocks _________ to the mid-ocean ridge were the ______________

Why do you think this is??

Sea-Floor Spreading 1960 – American

geologist ______________ proposed the __________ ________________________

› 1. Mid-ocean ridge is a huge ___________ in the earth’s crust where the hot _________ pushes up

› 2. The pieces of crust on either side of the crack are slowly moving _______ from each other

› 3. As they move, _______ _______ from the mantle wells up between them, forming ______ _________ ___________

Sea-Floor Spreading

New ocean crust is constantly being _______ during sea-floor spreading.

So why doesn’t the earth keep growing bigger??

Because at the same time, ________ ocean crust is being _________ ____ in deep _______ ___________!

The ______ _________ of oceanic crust stays the _______ and it is totally remade every ______ __________years or so.

Sea-Floor Spreading

Other scientists sampled rocks on ______ _______of the mid-ocean ridge

They found a pattern of _________ ________ _________ that was _________ on each side

Sea-Floor Spreading The stripes were

formed when the earth’s magnetic field caused ___________ to line up in the rocks

The stripes were different because earth’s magnetic field ___________ itself many times in the past

Shows that new ocean crust is added to ______ ________ of the mid-ocean ridge at the _________ _________

Activity

Watch movie “The Endless Voyage – Making the Pieces Fit” from Discovery Education

Write down 10 new facts that you learned and hand in at end of class

Lab Activity

Magnetic Patterns on the Ocean Floor

Page 98 in Textbook

Plate Tectonics Earth’s lithosphere

is divided into pieces called __________

The plates are _______ ___________, each at a different rate and direction

A lithospheric plate moves as a _______, floating on top of the ______________ (like a flat rock on wet cement)

Structure of Earth’s Plates Each lithospheric

plate is made up of both ______ _______________

________ ________ is dense and made up of ______ _____ ___________

_________ _______ is less dense and made up of _______ _____ ___________

Continental Plates

6 of the earth’s 7 major plates are ______________ plates

They carry mostly continental crust material

They consist of _____ continent and a large section of __________ ________

Oceanic Plates

One major plate and several smaller plates are oceanic plates

They are made up entirely of ___________ __________

Plate Boundaries

If plates are moving, what kinds of interactions are possible??

Demonstration with 2 students

Divergent Boundaries

Plates moving ________ from each other

Places where ________ _______ __ ____ _______

______ _____ ______are divergent boundaries

Can also occur in continents and signal the beginning of the continent’s ___________

Convergent Boundaries

Two plates _______ ________ ___ ________

Usually one plate moves _________ another and crust material is _________

Produce many different kinds of features on earth’s surface

Transform Boundaries

Two plates ______ ____ ________ ___________ beside each other

Crust material is ______ created or destroyed

The break or crack along which movement occurs is called a _____________ ____________

Activity

Watch first part of movie “Endless Voyage – World in Motion” from Discovery Education

Define the following and hand in at end of class:

Divergent BoundaryConvergent BoundaryTransform Boundary

Convergent Boundaries

__________ of 2 plates release huge amounts of _________

Energy causes important _________ __________ – volcanic activity or mountain building

What happens depends on the ______ ___ _______that meet or converge

Oceanic Plate –Oceanic Plate

The more dense plate is pushed down under the other – ______________

Lower plate goes into _____________, melts, and is absorbed into ___________

Causes ______ ________to rise up through other plate› Volcanoes form on ocean

bottom and build a chain or _______ ___ ____________

› It also creates a ________ _________ ______ – deepest parts of the ocean

Oceanic Plate – Continental Plate

____________ plate is always _________ so it will be pushed down under the ____________

Oceanic plate melts into ________________, causing molten rock to rise up through ______________ plate

___________ __________ forms, usually containing ___________

Continental Plate – Continental Plate

Both plates are the same __________ and _____________

Neither can move ___________ the other

They __________ and _________ each other, forming _____ ________

Plates become joined as a _______ _________

Plate Geography

Certain instruments measure the slow movements of earth’s plates, so the _______ and ______________ of most have been determined – can _______ future movement

The movement and location of plates explains many of earth’s features:› _______________________› _______________________› _______________________› _______________________› _______________________› _______________________

Well-Known Features of Earth

___________________

One of the few transform boundaries on land

Its movement causes severe _______________ (California)

Well-Known Features of Earth

________ ___________

Nazca plate ____________ under the South American plate caused this mountain range

Well-Known Features of Earth

______ _____ _____

New ____________ boundary beginning to split Africa in two

Well-Known Features of Earth

_________________ __________

mountains on earth Resulted from

____________ of two continental plates

Well-Known Features of Earth

_________________ Ocean trench

more than _______ _________________

Created by _____________ of Pacific plate under the Philippine plate

Measuring Plate Movement

_____ ______ ________ _____________(VLBI) Uses ________ signals from distant _______

(stars) to measure plate movement Two stations far apart on earth receive

signals from the same quasar Get a precise measurement of _________

between the 2 stations Make same measurement at a later date

– find out how fast the earth’s plates are ______________

Hawaii and Japan are moving closer to each other at a rate of __________________________

The North American and Eurasian plates are moving apart at a rate of ______________________

Activity - Answer the following questions on a sheet of paper and turn in by the end of class

1. What happens during sea-floor spreading? 2. Describe 3 types of plate boundaries, and

give an example of each. 3. Explain how mid-ocean ridges and

subduction zones are similar. How are they different?

4. Japan is made up of a long chain of islands formed from volcanoes. What kind of plate boundary do you think is nearby?

5. What happens at a continental-continental plate boundary?

Section 3 Physics of PlateMovement

Objectives:› Describe two models of how convection

occurs in the earth’s mantle.› Explain how a tectonic plate may move as

part of a convection cell.› Evaluate models explaining plate

movement by convection.› Compare and contrast two models for how

convection results in the movement of plates

Skills Warm-up

Convey the Concept› Describe how a conveyor belt works.› Make a list of where conveyor belts

are used.› What happens to objects on a

conveyor belt?

What Moves the Plates??

Scientists know:› ___________________

___________________› ___________________

___________________› ___________________

___________________ Still don’t know for

sure what the driving force of plate movement is!

Convection in the Mantle

Driving force for plate movement has something to do with ____________________________________

_____________ cells occur in the mantle, which are circular units of movement

But how exactly does convection occur??

Two Models for Convection

How Does Convection Move the Plates?

First Model - Passive Plates are _______________

_________ with the movement of convection

Plates are like ___________ on a giant conveyor belt

________ _____________ form where convection pushes material up

_______ ______________ form where convection goes back down into the mantle

How Does Convection Move the Plates?

Second Model - Active Plates themselves have

an _______ ______ in convection

A plate is ________ and ______ _______ than the asthenosphere

It will sink into a _________ ________and pull the rest of the plate down

This helps _________ the circular movement of convection

Activity - Answer the following questions on a sheet of paper and turn in by the end of class

1. What are two models for convection in the mantle?

2. If convection cells in the mantle are like conveyor belts, what are plates like?

3. Which model do you think best explains how convection moves the plates? Explain the reason for your choice.

4. What are the similarities and differences between the two major models explaining how convection causes plate movement?