2. Warm up  Which landform is most likely to form where two oceanic plates push together?  A. folded mountains  B. mid-ocean ridge  C. river valley  D. volcanic island

3. Quiz  1. _______ is melted rock under earths surface.  2. __________ is melted rock that reaches earth’s surface.  3. What forms when continental crust collides with continental crust?  4. What happens when oceanic collides with oceanic crust?  5. What happens when oceanic collides with continental crust ?

4. Divergent boundaries  When two plates move apart- divergent boundary

5. Sea-floor spreading  Sea-floor spreading is: When two oceanic plates move apart magma fills in the space between them When the magma cools it forms new crust The oceans are widened and long continuous mountain chains form along the boundary called mid-ocean ridges

7. Earthquakes  Earthquake is the shaking of ground that occurs when rock in Earth’s crust breaks, or slips and releases pressure  A break or crack in Earth’s surface where this movement occurs is called a fault Can slide upward, downward or side by side

8. What causes tectonic plates to move?  The differences in temperature in the asthenosphere causes convection currents that cause the plates to move

9. Convection Currents