2.  Pangea  A land mass created by Alfred Wegner  Alfred Wegner  was a German scientist who claimed the continents were once joined.  Fossils  Fossils of animals supported his theory. Scientists found the bones of a Mesosauras in South America and Africa, but both of them are far apart.

3.  The fossil of a plant called the glossopteris was found on 5 different continents.

4.  They once had a similar climate and this is shown through plant fossils  Glaciers sediments were found in hot places, but glaciers are usually found in cold places.  The same rocks found on the Appalachian mountains, located in Eastern US, were found in Greenland and Western Europe.

5.  Seafloor mapping is when people drop ropes over boats until they reach the seafloor.  The rope method was used until they figured out how to use sound waves to locate submarines.  Mid ocean ridges are what forms when the seafloor spreading occurs Harry Hessis is an American Scientist that purposed the idea of seafloor spreading.  Magnetic fields also helped the theory of seafloor spreading because rocks with iron record magnetic reversal.

6.  The definition of seafloor spreading is when magma or melted rock under the earth’s crust is forced up toward the surface at mid ocean ridges, forming new seafloor.  Evidence of this theory was scientists found rocks that were near the ridges to be younger than those farther away.

7.  Plate tectonics are large sections of the earth’s crust and mantle  The lithosphere is the rigid upper mantle the layer below is the asthenosphere. The asthenosphere is a plastic or jelly like layer on which the plates move on.  There are 3 different boundaries: divergent, convergent, and the transform boundary. The divergent boundary is when 2 plates separate, convergent boundaries are when 2 plates collide, and transform boundaries are when 2 plates slide and rub against each other.

8.  Convergent: volcanoes or mountains  Convergent oceanic: volcanoes  Convergent continental: Mountains  Divergent: Seafloor spreading and ridges  Transform: earthquakes, faults, and rift valleys

9.  Convection currents are when heat rises, then cools and sinks, then repeats again.  Rift valleys and faults get formed when the plates slide over or past each other. An example is the Great rift valley.  Large cracks that forms when crust gets pulled apart.  Mountains form when 2 continental plates collide  Volcanoes form when 2 oceanic plates collide  Strike slip faults form at transform boundaries. An example of this is the san Andreas fault.