Forces of Change With a partner, brainstorm a list forces that change the surface of our planet.

Earth is a Layered Planet… Core - center of planet, very hot Inner = solid Outer = liquid Mantle - layer of hot, dense rock (solid & liquid) Crust - outer layer, rocky shell

Plate Tectonics Continental Drift - theory that all continents were once joined but later drifted apart. Pangaea - super continent Plate Tectonics - plates move slowly to create many of Earth’s physical features.

RING OF FIRE!

Internal Forces Mountains – formed when continental plates collide Subduction - heavy sea plate dives under light continental plate. Volcanoes - sea plate becomes magma and bursts through crust to form mountains (Andes)

Internal Forces… Folds are caused when moving plates squeeze Earth’s surface until it buckles Faults occur when plates slide past each other, creating cracks San Andreas Fault Earthquakes are sudden, violent movements of tectonic plates along a fault line.

External Forces of Change Weathering (No movement) Physical – rock is broken into fragments by wind or water Chemical – changes the chemical makeup of rocks Acid Rain Erosion (Movement) Wind – involves the movement of dust/sand/soil Glacial – large bodies of ice that carve Earth’s surface Water – flow of water wears away rock/soil Source: http://www.nature.nps.gov/geology/usgsnps/misc/gweaero.html

Questions? Write a summary that explains the forces that change the earth (make sure to include examples in your summary).