forces that change the earth. forces that change earth!

Forces that Change the Earth

Forces that Change Earth!

Forces that Change Earth!

YOU LOSE

REPLAY???

REPLAY???

Oh. Fred’s daydreaming again after going brain-dead playing FINAL WARDEATH UNIVERSE DUEL OF CHAOSLORDS VII for 14 hours straight. Get a job, Fred.

#1 What Fred fails to realize is……that the Earth does change, but just not in the way he’s imagining. Some changesare very obvious and happen suddenly and with great force:

However, most of Earth’s changes are VERY slow. They’re so gradual that they’re reallyhard to notice unless it’s your job to watch for such things.

Let’s see some ways in which Earth changes constantly, both slow and fast.

#2 A look inside…Why do these bananas look like this?

It’s because of chemical changes in the sugars andproteins inside the banana. Much like your body,your outward appearance very much depends on your inner workings.

The Earth is no different. To study the surface of theplanet requires an understanding of the insides of theplanet.

Earth’s LayersThe Earth's rocky outer crust solidified billions of years ago, soon after the Earth formed.

This crust is not a solid shell; it is broken up into huge, thick plates that drift atop the soft, underlying mantle.

The Crust

Outermost layer 5 – 100 km thick Made of Oxygen, Silicon, Aluminum

The Lithosphere & Asthenosphere

Lithosphere is in the Crust & Mantle

Asthenosphere is in the Mantle

Lithosphere & Crust are rigid and solid

Asthenosphere is plastic like and moves (where the convection currents flow)

The Mantle Layer of Earth

between the crust and the core

Contains most of the Earth’s mass

Is the largest layer Has more

magnesium and less aluminum and silicon than the crust

Is denser than the crust

The Core

Below the mantle and to the center of the Earth

Believed to be mostly Iron, smaller amounts of Nickel, almost no Oxygen, Silicon, Aluminum, or Magnesium

Tectonic Plates8 Major Plates out of 3000 Plates

Plate Tectonics

Greek – “tektonikos” of a builder Pieces of the lithosphere that move around Each plate has a name Fit together like jigsaw puzzles Float on top of mantle similar to ice cubes

in a bowl of water

Continental Drift

http://members.enchantedlearning.com/subjects/astronomy/planets/earth/Continents.shtml

Alfred Wegener 1900’sContinents were once a single land mass that drifted apart.

Fossils of the same plants and animals are found on different continents

Called this supercontinent Pangea, Greek for “all Earth”

245 Million years ago

Split again – Laurasia & Gondwana 180 million years ago

Evidence of Pangea

Sea Floor Spreading

Sea Floor Spreading

Mid Ocean Ridges – underwater mountain chains that run through the Earth’s Basins

Magma rises to the surface and solidifies and new crust forms

Older Crust is pushedfarther away from the ridge

How Plates Move

http://pubs.usgs.gov/gip/dynamic/unanswered.html

Different Types of Boundaries

http://pubs.usgs.gov/gip/dynamic/understanding.html

Plate MovementsPlates can move in three ways.

Apart

Together

Past each other

Fred can you demonstrate for us?

Not that kind of plate Fred!

Plates Moving ApartWhat does that cause?

Write It!

Divergent boundary – when plates move apart forming a rift valley or a ridge.

Good question Fred!

It forms the ridges in the ocean like this one the Mid-Atlantic Ridge. The plates pull apart and new land is created as it bubbles up from the mantle creating a ridge.

Divergent Boundary – Arabian and African Plates

The Great Rift Valley

As plates move apart they can also cause a valley like the Great Rift Valley in Africa.

Ok Fred how about plates moving together?

Not quite Fred!

Plates pushing together what do they cause?

When plates of the same density collide the buckle and form mountains.

If one plate is less dense than another subduction occurs. One plate slides under the other and volcanoes or mountains are formed.

Write It!

Divergent boundary – when plates move apart forming a rift valley or a ridge.

Convergent boundary – when plates move together forming mountains or volcanoes.

Convergent Boundary – Indian and Eurasian Plates

One more chance Fred plates moving past each other.

Fred that is just wrong!

Plates that Move past each other and what they cause.

Where plates slide past each other transform boundaries occur. They create faults and when they move they cause a great deal of damage in the form of earthquakes.

FaultsThe fault you are most familiar with is the San Andreas Fault in California. There have been several earthquakes in California that have caused major damage.

Earthquake damage.

Write It!

1.Divergent boundary – when plates move apart forming a rift valley or a ridge.

2.Convergent boundary – when plates move together forming mountains or volcanoes.

3.Transform boundary – when plates move past each other causing earthquakes.

Well that is the end of this lesson time to check for understanding!

When one plate pushes against another it causes uplift. This uplift will likely result in a

A. Rift

B. Mountain

C. Ridge

D. Valley


What causes the earthquake activity in California?

A. High Tides

B. Low Tides

C. Plate Movement

D. Volcanic Activity


What caused the damage seen in the picture?

A. Soil Erosion

B. Heavy Rains

C. Horizontal Movement of the Earth’s crust

D. Volcanic eruption


Plates pushing together cause

A. Earthquakes.

B. Rift Valleys.

C. Mountains.

D. Rivers.

forces that change the earth. forces that change earth!

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