Changing Nature of Earth

Mr. Lin

Image Courtesy of http://www.spacetoday.org/images/SolSys/Earth/EarthBlueMarbleWestTerra.jpg

Look at the World Map. It looks like a puzzle. Can anyone tell me why?

Image Courtesy of http://www.tlrp.org/international/images/world.gif

Theory of Continental Drift

Image Courtesy of http://www3.bc.sympatico.ca/Moon/earths.gif

Image Courtesy of http://geology.com/pangea-continental-drift.gif

Theory of Continental Drift

Image Courtesy of http://www.noc.soton.ac.uk/gg/classroom@sea/carlsberg/images/plate_history_lge.jpg

Theory of Continental Drift

• A Theory that all the continents on Earth were originally a part of one large super-continent called Pangaea.

• Plates on the Earth’s Crust have since moved parts of Pangaea away from each other.

Image Courtesy of http://upload.wikimedia.org/wikipedia/commons/6/65/Pangaea.png

PANGAEA

How Do the Continents Move?

Plate Tectonics

• The Earth’s surface (called the Crust) is cracked into large “plates”

• These plates float on the molten rock under the crust.

Image Courtesy of http://www.gsi.ie/NR/rdonlyres/A3B07F5E-D9BB-4026-908D-DEB9B0217EA6/0/earth_cut.jpg

Plates

Image Courtesy of http://www.dkimages.com/discover/previews/1244/597340.JPG

Plates

Image Courtesy of http://www.windows.ucar.edu/earth/images/earth_plates_usgs_L.jpg

Plate Tectonics

Show Video on Plate Tectonics

Plate Tectonics

• When Plates are next to each other, they can move in three main ways:

– Away from each other• Divergent

– Into each other• Convergent

– By sliding• Transformational

Image Courtesy of http://geothai.net/2008/images/stories/article_image/convergent-boundary-oceanic-continental-still.gif

Convergent Plates

Convergent PlatesMountains like Mt. Everest are built by Convergent Plates

Divergent Plates

Transformational

MwwwaaahahahahAHAHA

H!!!So What Moves the Plates?

(Let’s first investigate the layers of the

EARTH)

Layers of the Earth

• Crust: Solid rock

• Mantle: Melted rock

• Outer Core: Melted metal

• Inner Core: Solid Metal

Image Courtesy of http://www.mgm.monschau.de/seismic/images/artikel/abb10_gross.jpg

Inner Core: 800 miles thick. Made of solid nickel and iron

Outer Core: 1,400 miles thick. Made of liquid nickel and iron

Mantle: 1,800 miles thick. Made of magma

Crust: 3-5 miles thick. Made of rocks

Layers of the Earth

Image Courtesy of http://volcano.und.edu/vwdocs/vwlessons/lessons/Earths_layers/Earths_layers3.html