NSSS1.5

toc =1.5 The Theory of Plate Tectonics=

Vocabulary

 * Plates**: the separate sections of the lithosphere
 * Scientific Theory**: a well tested concept that explains a wide range of observations
 * Plate Tectonics**: the geological theory that states that the Earth's plates are constantly in motion
 * Faults**: breaks in the Earth's crust where rocks have slipped past each other
 * Transform Boundary**: a place where two plates slip past each other, moving in opposite directions
 * Divergent Boundary**: the place where two plates move apart
 * Rift Valley**: a deep valley which forms along divergent boundaries
 * Convergent Boundary**: the place where two plates come together

A Theory of Plate Motion

 * ===Plate tectonics===
 * Driven by convection currents in the mantle
 * Convection currents rise in the asthenosphere and spread out in the lithosphere

Plate Boundaries

 * ===Transform Boundaries===
 * Earthquakes occur frequently along these boundaries
 * ===Divergent Boundaries===
 * Occur along the mid-ocean ridge
 * Also occur on land
 * Rift valleys occur near divergent boundaries
 * ===Convergent Boundaries===
 * When 2 plates converge, they cause collisions, subduction occurs and mountain ranges form.
 * Oceanic crust and oceanic crust( subduction occurs)
 * Continental crust and oceanic crust( collisions happen)
 * Continental crust and continental crust( mountain ranges form)
 * Density determines which plate comes on top
 * Can create mountain ranges