As we begin our unit on the Changing Earth, we start the school year with Plate Tectonics. The Theory of Plate Tectonics began with Alfred Wegner's hypothesis of continental drift.
What evidence was used for continental drift?
What evidence do we use today for the Theory of Plate Tectonics?
What are the layers of the earth? Why do they form as layers? What are the porperties of each layer?
Contract Week 1 has you modeling the inside of the earth or predicting where plates will move to in 100 million years.
3 comments:
1. Some evidence of continental drift is that fossil species in continents that would only be possible if the two continents were together.
2. Evidence of the Theory of Plate Tectonics could be that the continents move about 0-100mm every year (as measured by laser positioning systems).
3. The layers of earth are Crust, Mantle, Outer core, and Inner core. There are two more layers, they are the Lithosphere and Asthenosphere. The Lithosphere is in the Crust and is the outermost shell of the planet and is where the tectonic plates are. The Asthenosphere is is in the upper
part of the mantle right beneath the lithosphere is involved in plate tectonic movements.
Shortly after Earth's formation and early crustal formation, an occurence called 'The Iron Catastrophe' occured, where iron sank to the center of the planet. The heat released from this occurence literally melted the entire planet, and as the iron sank to the center, lighter materials rose, the lightest forming the crust. The density of materials increases with depth. Although uranium and other heavy elements are found in the crust, it is due to their chemical preference to appear as a trace element in the silicate crust than to appear in the core.
The properties of the crust are
The layers of Earth include The crust,lithosphere,asthenosphere,mantle,outer core,and inner core. They form as layers because the compostion of each layer can have different densities.
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