NCERT Class 7 Geography Chapter 2: Inside our Earth Completes Notes Part 4

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Inside Our Earth

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Rock Cycle – Transformation

Image Understanding for Rock Cycle – Transformation

Image Understanding for Rock Cycle – Transformation

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Rock Cycle and 3 Types of Rocks

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Now let’s understand this in brief. So you have volcano that erupt off here and you have solidification of magma. This solidification leads to formation of igneous rocks. Now when this igneous rock is formed overtime there is breaking of all from the agents of weathering and nitrogen you have breakup of the rocks that occurs and you have formation of sediments. Now these sediments keep on depositing forms the sedimentary rock. Now either this sedimentary rock or igneous rock under high temperature and pressure would leave to formation of metamorphic rock. Now what would happen? How was the metamorphic rock formed? When the metamorphic rock is formed it would compress and be compressed to point that it becomes to translate into kind of melted state and that melted state would again form the core for the magma for irruption of volcano and this cycle keeps on continuing and there for I can say rock cycle merely a transformation from one rock structure to another rocks structure. Now when we are clear about rock structure and rock cycle, what we must and must know are the mineral.

Minerals

  • Naturally occurring substances

  • Have certain physical properties

  • Definite chemical composition

  • Fuels – Coal, Petroleum & Natural Gas

  • Industries – Iron, Aluminum

  • Medicines – Calcium, Phosphorus, Magnesium

In simple terms I can say rocks contain minerals and this are naturally occurring substances that are present in a rocks. There are two major properties that you must and must know for minerals. They have certain physical property that’s the first important thing and they have a kind of definite chemical composition that can be seen. Now there are various minerals which can be used for various purposes. For example if I say minerals which are used as fuels a common example is coal, Petroleum and Natural gas. When I say mineral which are used in industries it is Iron, Aluminum so on and so forth. When I say mineral which are used for medicines of fertilizers can be phosphorus, magnesium and then you have calcium which is used mainly in the medicines. So these are the some common minerals that are used and we have talked about the minerals and their applications and the two important properties of the minerals. First of all they have certain physical characteristics of physical properties and definite chemical composition that can be seen for the minerals. So with this we cover the chapter 2 Inside Our Earth.