Convection Currents Essay

There are many different reasons why the earth’s crust is moving. Some for example are the friction between two plates causing major earthquakes. Sometimes when this plates are pushed together they form fold mountains or ridges. Today we know that the continents are gradually moving apart. Therefore the there is new rocks created in between those areas. New volcanoes are created and new rocks are formed. Plate tectonics allow scientists to know about the earth’s centre. The oceanic plate slides under the continental plate because it is heavier. Once it goes under the continental plate it melts into the asthenosphere. The Richter scale is a scale that scientists use to measure the magnitude of an earthquake. It can tell us how much the earth’s crust has moved (how hard; effecting the surface). A shift along a fault on the continental crust could also cause earthquakes. Teacher copy The earth’s crust I s made up of sections called plates. These sections ‘float’ on the liquid mantle and slowly move around. The movement of the plates is caused by convection currents. A convection current is how a liquid moves when it is heated. Hot liquid rises up and pushes the cooler liquid out of the way. In the mantle, this is happening all the time. As the liquid rock moves, it can push the continents on the plates In this diagram you can see the convection currents in the mantle and the direction In the middle of the ocean, new rock is formed when hot rock from the mantle rises up. At the edges of ocean, old crust is destroyed when it stinks down under the continent an melts again. In this diagram, you can see new crust forming at the mid-ocean ridge and pushing the old crust towards the continent.