Formation of the Earth In the beginning

Just a lot of Gas Space contained a lot of gasses and dust That gas and dust began to condense and heat up Matter in the middle heated so much the gasses ignited BANG! http://en.wikipedia.org/wiki/Galaxy

After the Bang After the gasses exploded it threw material out As the material moved away from the sun it started to cool forming planets http://www.psc.edu/publicinfo/news/2002/images/planets-01-full.jpeg http://www.windows.ucar.edu/tour/link=/jupiter/atmosphere/J_evolution_4.html

Forming Earth Earth was formed from the dust and gasses that were left after the bang Earth started off as a rock. It was hit by meteors over billions of years, which added to the mass of the planet. As the planet cooled the heavier, more dense metals began to sink to the inner part of the earth http://www.ccsf.edu/Departments/History_of_Time_and_Life/content/EarthLayers.htm

Formation of the Earth

Layers of the Earth As the molten earth material cooled layers formed Crust Mantle Outer core Inner core http://www.ccsf.edu/Departments/History_of_Time_and_Life/content/EarthLayers.htm

How do we know? Can’t see into the earth Have only drilled into a small part of the earth Learned what we know by studying seismic waves and how they travel http://pubs.usgs.gov/gip/earthq1/corel.gif

Outer and Inner Core

The Crust The crust is the outermost layer of the earth It is made of two types of crust Continental (35-100 km) Oceanic (5-10 km) It is not very thick 5-100 km thick We have only drilled about 5 miles (8 km) into the crust It’s a solid Where we live http://www.sirinet.net/~project/MeersEarthsCrust.html http://www.dlt.ncssm.edu/TIGER/diagrams/basics/ElementsInEarthsCrust.gif

The Mantle Is found under the crust Is made mostly of iron (Fe) and magnesium (Mg) Where most of the earth’s heat is Has convection cells that cause the plates to move Volcanoes give us a clue to what is under the crust http://www.physics.sfasu.edu/astro/courses/ast105/Summary7_files/07-01.jpg

Convection – hot rises, cold sinks

The Outer Core Is about 2200 km thick Made mostly of iron (Fe) and nickel (Ni) Is a liquid The outer core is liquid, unlike the inner core. http://library.thinkquest.org/10136/media/layers2.jpg

The Inner Core Is a solid Is 1228 km thick Due to extreme pressure from all the other layers of the earth Is 1228 km thick Made of mostly iron (Fe) with some nickel (Ni) http://www.llnl.gov/str/JulAug04/Fried.html

Other Names Crust and upper mantle – lithosphere Where the tectonic plates are found Bottom of the upper mantle – asthenosphere Where the convection cells are Lower mantle - mesosphere http://www.visionlearning.com/library/modules/mid69/Image/VLObject-1630-030917010902.gif

Draw the layers of the Earth Pages 90 and 91 in “Inside the Restless Earth” Include the following words; Crust, mantle, Outer Core, Inner Core, Lithosphere, Asthenosphere, Mesosphere.