Tectonic Plates

Tectonic plates are huge rocks that we live on.Tectonic plates form Earth's mountains, volcanos, and earthquakes.

Types of Plate Boundaries

      There are divergent boundaries where the plates move apart and push lava up creating volcanos and mountains. Convergent boundaries are where the plates push aganist each other and one goes under the other (also called a subduction zone). Transform boundaries grind against each other creating friction and stress. When too much stress is built up, the plates suddenly move and create earthquakes. The bigger the stress the bigger the earthquake.

Number of Plates

There are 18 major plates that make up the earth, but there are many more smaller plates. These plates are always changing shape and form when they more.

Location of Plates

The plates are floating on the top of the liquid mantle in which they are constantly moving and changing shape. They move about one inch each year. The places where the plates come together are where the most volcanoes happen.

Sea Floor Spreading

Sea floor spreading is the same thing as a divegent boundery. This is where two plates move apart from each other. Magma leaks out and forms new rock. This is also where mountains and volcanos are formed.

Mid-Ocean Ridge

The mid ocaean ridge is were magma comes up from the mantle. The rock starts spreading apart from each other causing the continents to push away from each other. They push away because the lava that is there has to go some place or just spread apart from each other. They also great new rock to push the continents away because of all that old lava.

Plate tectonics

Scientists belived that about two million years ago all of the continents were once one super continent. This idea was called the continential drift theory. The super contient called Pangea, was belived to of been a C-shaped landmass covering the equator . Reasearchers think that Pangea broke up about 180 million years ago into two pieces. Then afterwards forming our seven continents. Alfred Wenger was the first to catch on to this theory, thinking somehow that the continents drifted apart. However, no one belived him and wanted more proof.

Alfred Wegener

   Alfred Wegener was the first person to start thinking that our continents was one big piece of land a long time ago. He thought this because there were spieces of animals from other countries. He also looked at Earth's maps and saw that some of our continents fit together like a jigsaw puzzle. Scientists named that ultra country Pangea. Alfred also thought this because he found fossles of the same kind in the same region that could not live where he found them. Alfred also found that the two fossils were almost identical.  

Interesting Websites:Seafloor Spreading