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The Changing Earth A Science Lesson for 5th Grade http://www.dc.peachnet.edu/~pgore/students/w97/lehrer/ http://www.geo.utexas.edu/outreach/Barker%20lecture/barker.htm Earth’s Layers • The three layers of Earth are the crust, the mantle, and the core. (see diagram to the right) See the cutaway view and learn more about the Earth's layers. • Crust: the thin, outer layer of Earth • Mantle: A thick layer of rock between the crust and the core of Earth • Core: the innermost layer of Earth, which consists of a molten outer part and a solid inner part. • Want to learn more? Click here! http://www.geog.ouc.bc.ca/physgeog/contents/i mages/earthcut.jpg Text B19 THE THEORY OF PLATE TECTONICS • Plate Tectonics is the theory of continents drifting from place to place breaking apart, colliding, and grinding against each other • See Pangaea split into the seven continents • Alfred Wegener discovered fossil remains on separate continents that proved the continents were once one giant landmass called PANGAEA • Click on the map for a closer view of the Earth's plates. http://www.exploratorium.edu/faultline/earthquakescience/images/pangea_lrg.gif THE THEORY OF PLATE TECTONICS (CONTINUED) • Now you try it...see the plates move. http://www.lr.k12.nj.us/ETTC/archives/platetectonics2.jpg TECTONIC PLATE MOVEMENT • Plate boundaries are places where plates interact and many earthquakes and volcanoes occur. The three main boundaries are: 1. Convergent boundaries where plates move together 2. Divergent boundaries where plates move away from one another 3. Transform-fault boundaries where plates move past one another http://www.mrd.gov.fj/gfiji/geology/educate/platect.html Mountains • Mountains form as the result of four basic processes: 1. Folding – when masses of rock are squeezed from opposite sides (two plates collide). 2. Faulting – when blocks of rock move up or down along a fault. 3. Doming – when the surface is lifted up by magma. 4. Volcanic Activity http://www.anamericandream.net/testimonials.html Earthquakes • View a globe showing where earthquakes have occurred over a five year period. • Do you have questions about earthquakes? Find the answers here! • See these animated faults in motion! http://pubs.usgs.gov/gip/earthq1/san_andreas.gif EARTHQUAKES (CONT.) http://www.ga.gov.au/news/images/GA1117.gif • The instrument used to record the intensity, duration, and nature of earthquake wakes is a seismograph. • The Richter scale is a scale of numbers by which the magnitude of earthquakes is measured. Volcanoes • A volcano is any opening in Earth’s crust through which hot gases, rocks, and melted material erupt. • The melted material that erupts is called magma. • Want to learn more about volcanoes? Click here! http://rwor.org/i/volcano.gif VOLCANOES (CONT.) • A volcano erupts in certain steps: 1. High temperatures and pressures deep within Earth cause rock to melt. 2. Magma makes its way toward the Earth’s surface melting surrounding material to form a central pipe. 3. Hot melted material moves through the volcanic vent. 4. Magma turns to lava. • Watch this animation of a volcanic eruption! http://www.geo.mtu.edu/volcanoes/hazards/primer/image s/volc-images/puuoo.jpg