Geography Summary :: Papers

Geography Summary A very long time ago, in outer space. There was an atom, invisible to the naked eye. No one knows how the atom was created, it was just there. This atom was very concentrated and very dense. Approximately 30 billion years ago, that atom exploded and out came the material used to create the entire universe. Of course, back then. The universe was very different from today. This is the big bang theory, it wa sproposed by George Gamow a Russian American. According to the theory, the force of the explosion is still making us drift and then will pull us back bringing our existence to an end. When the earth was first created, there was only one continent. It was called Pangea. The Pangea then split up into two smaller continents named respectively Laurasia and Gondowanaland. Finally, both Laurasia and Gondowanaland split up into yet smaller continents, resulting in a final count of 7 continents. This theory is called Continental Drift and it was suggested by Alfred Wegener in 1912. Convection currents is how heat moves in liquids. We find convection currents inside the moho but we can also find convection currents in a pot of boilling water. Convection currents are circles of heat side by side moving in opposite directions. When these happen inside the moho, many things can happen. At some points on the earth parts of the crust can be sucked underground make cracks on the ground. At other places on earth, the currents can push up the crust, thus making a hill. Convection currents are what causes tectonic plates to move. With out convection currents, there probably wouldn`t be any continental drift. As you learnt in the previous paragraph, convection currents take place in the Moho. The Mohorovicic discontinuity is the boundary between the crust and the mantle. The material inside the moho are smi molten rocks.