Understanding Continental Drift and Plate Tectonic.Describing the Internal Structure of the EarthExplaining the processes & forces creating Continental Drift and Plate TectonicsDescribing what happens at each typr of Plate Boundary (x6)

Understanding Continental Drift and Plate Tectonics: Continental drift is the theory that the Earth's continents have moved over geologic time relative to each other. This theory was proposed by Alfred Wegener in 1912. Plate tectonics is the theory that Earth's outer shell is divided into several plates that glide over the mantle, the rocky inner layer above the core. These plates move due to the convective forces in the underlying hot mantle.

Describing the Internal Structure of the Earth: The Earth is made up of three main layers: the crust, the mantle, and the core. The crust is the outermost layer where we live. The mantle lies beneath the crust and is about 2,900 kilometers thick. It's mostly composed of silicate rocks rich in magnesium and iron. The core, the innermost layer, is primarily composed of iron and nickel. It's divided into two parts: the outer core, which borders the mantle, and the inner core. The boundary separating these regions is called the Bullen discontinuity.

Explaining the processes & forces creating Continental Drift and Plate Tectonics: The main force that drives continental drift and plate tectonics is the movement of the semi-fluid mantle beneath the crust. This movement is caused by the heat generated from the radioactive decay of elements such as uranium and thorium in the mantle. This heat causes the material in the mantle to rise towards the crust, cool, and then sink back down. This convection current causes the movement of the tectonic plates in the Earth's lithosphere.

Describing what happens at each type of Plate Boundary: There are three types of plate boundaries: convergent, divergent, and transform.

• Convergent boundaries: These occur when two plates move towards each other. If two oceanic plates converge, the older, denser plate will sink into the mantle in a process called subduction. If an oceanic and a continental plate converge, the denser oceanic plate will subduct beneath the continental plate. If two continental plates converge, they will crumple and fold creating mountain ranges.

• Divergent boundaries: These occur when two plates move away from each other. This usually happens at the bottom of the oceans, where new crust is formed by magma that rises to the Earth's surface at the mid-ocean ridges and cools.

• Transform boundaries: These occur when two plates slide past each other horizontally. The friction caused by the sliding of the two plates can trigger earthquakes. The San Andreas Fault in California is an example of a transform boundary.