Download Formation of Mountains: Geology Lesson for Teachers and more Study notes Geology in PDF only on Docsity! Lesson 3: The formation of mountains Factsheet for teachers Vocabulary This lesson uses the following geographical terms. These should be used and explained to pupils as the lesson is taught. Core, mantle, crust These are the main layers of the Earth. These are described in more detail below. Molten rock Rocks that are in a liquid form. Viscous Viscosity is a measure of how thick or thin a liquid is. The higher the viscosity, the thicker the liquid; the lower the viscosity, the thinner the liquid. If a liquid is described as viscous it is thick. The mantle is viscous. Magma Magma is molten rock from the mantle. Magma is within the surface of the Earth. Magma becomes lava only once it flows out over the surface land, for example with a volcanic eruption. Plates The Earth’s crust is not one solid piece of land, but is formed of many different pieces or plates. There are eight major plates and many more minor plates. These plates move across the mantle. Plate boundary Where tectonic plates meet. Plate tectonics This is the theory of the movement of the plates that make up the Earth’s crust. Convection currents Heat from the Earth is released in currents within the mantle. This is analogous to bubbling porridge in a saucepan. The convention currents within the mantle cause the Earth’s plates to move. Faults/fault lines These are cracks in the rocks that make up the Earth’s crust. When these are evident blocks of the crust can be forced in different directions- up, down or stacked on top of one another- along the faults. Faults can occur at scales of a few centimetres or, as in the case of fault block mountains, at scales of tens of kilometres. Converge When two plates move towards each other Anticlines These are the upward folds of a fold mountain. Synclines These are the downward folds of a fold mountain. Erosion/weathering This is the process whereby rocks are worn away through the action of wind and rain. Water can also penetrate rock, and when it freezes in winter, can expand, weaken the rock and lead the rock to crumble. Rock strata Layers of rock, one above the other, that form the crust rather like the layers in a cake. The Structure of the Earth Inner core The inner core is the centre. It is primarily a solid ball of iron. It has a temperature of 5500 O C- almost as hot as the outer layer of the sun, which has a temperature of 6000 O C. The inner core has a thickness of 1220km. (A distance of 1220km is equivalent to London to Ben Nevis- the UK’s highest peak- and back again). The inner core is solid due to the pressure exerted on it from the other layers. Outer core The outer core is composed of iron and nickel. Unlike the inner core, the outer core is liquid. It has a similar temperature to the inner core. Mantle This is the thickest part of the Earth, at 2900km. The mantle is viscous and composed of semi-molten rock or magma. A useful analogy is to think of the mantle having the consistency of Blu-tack, not quite a liquid and not quite a solid. It is composed of many different rocks and minerals including iron, magnesium, nickel, silicon and oxygen. Crust This is the outer layer of the Earth’s surface. It is the thinnest layer, between 0-60km. It is composed of solid rock and rests on the top layer of the mantle. It is in the crust (and the very upper layer of the mantle) that mountains are formed. When it comes to depth, think of the crust as the skin of a tomato, rather than the peel of an orange. In order to help pupils appreciate, and visualise, the thickness of each of the layers use Google Earth. The ruler function on Google Earth can allow you to measure the distance from your school to any other location. Crust Mantle Outer core Inner core
