P3+-+Plate+Tectonics

=Plate Tectonics= Plate Tectonics is the theory that the Earth's crust is seperated into plates that drift on top of the manle very slowly (about 2 inches per year), and about 300million years ago they were one single continent called Pangea.

History
Plate tectonics had their beginning in 1915 when Alfred Wegener he proposed the theory of "Continental Drift". He noticed that all of the contine n ts seemed to fit together like a puzzle, b ut he wasn ' t the only one who noticed this puzzle like feature. He was the first one to realize that the crust of the earth has changed over time. Wegeners theory was controversial because there was no evidence of why the continets were moving. He believed that the continents were were once one big continent called Pangaea meaning "All lands". Over time the continents drifted to their current spot. Pangaea started to break apart about 300 million years ago during the Carboniferous Era.

Plate Tectonics and Earth's Layers
T he rigid outer layer of the Earth, called the lithosphere, is made of plates which fit together like a jigsaw puzzle. The plates are made of rock, but the rock is lightweight compared with the denser, fluid layer underneath. This allows the plates to "float" on top of the denser material. Alfred Wegener came up with a crazy idea. He said "Maybe they were once all joined together in a single, giant landmass that broke up and drifted apart over time?" He decided to give this supercontinent a name and called it //Pangea//, meaning, "all lands". He presented his idea to the scientific community it came to be known as **//continental drift theory//**.