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NCERT Class 7 Geography Chapter 2 Inside Our Earth talks about the Earth and its constant changes inside and outside. The chapter starts by providing a brief about rocks, the types of rocks and how such rocks are formed. Students also learn about the importance of the crust inside the earth and how it helps in the formation of our planet’s surface. In this blog, we will provide you with CBSE Class 7 Geography Chapter 2 notes including important definitions, important questions, solved answers, and a free PDF.
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Table of Contents
Inside Our Earth Class 7 Notes
Let us now look at the important definitions of Class 7 Geography Chapter 2.
Important Definitions in NCERT Class 7 Geography Chapter 2
- Fossils: The remains of the dead plants and animals trapped in the layers of rocks are called fossils.
- Crust: The uppermost layer over the earth’s surface is called the crust. Read more to learn about the most abundant metal in the Earth’s Crust.
- Nife: The innermost layer is the core with a radius of about 3500 km. It is mainly made up of nickel and iron and is called nife.
- Rock: The earth’s crust is made up of various types of rocks. Any natural mass of mineral matter that makes up the earth’s crust is called a rock.
- Primary Rocks: When the molten magma cools, it becomes solid. Rocks thus formed are called primary rocks.
- Extrusive igneous rocks: When this molten lava comes onto the earth’s surface, it rapidly cools down and becomes solid. Rocks formed in such a way on the crust are called extrusive igneous rocks.
- Intrusive igneous rocks: Sometimes the molten magma cools down deep inside the earth’s crust. Solid rocks so formed are called intrusive igneous rocks.
- Sediments: Rocks roll down, crack, and hit each other and are broken down into small fragments. These smaller particles are called sediments.
- Sedimentary rocks: These loose sediments are compressed and hardened to form layers of rocks. These types of rocks are called sedimentary rocks.
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Download Social Science Class 7 Geography Chapter 2 Important Questions and Answers PDF
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Important Questions in NCERT Class 7 Geography Chapter 2: Free PDF Download
1. Answer the following questions.
(i) What are the three layers of the earth?
The three layers of the earth are Crust, Mantle and Core.
(ii) What is a rock?
The earth’s crust is made up of various types of rocks. Any natural mass of mineral matter that makes up the earth’s crust is called a rock.
(iii) Name three types of rocks.
The three types of rocks are Igneous Rocks, Sedimentary Rocks and Metamorphic Rocks.
(iv) How are extrusive and intrusive rocks formed?
Lava is fiery red molten magma coming out from the interior of the earth on its surface. When this molten lava comes onto the earth’s surface, it rapidly cools down and becomes solid. Rocks formed in such a way on the crust are called extrusive igneous rocks. They have a very fine-grained structure. For example, basalt. The Deccan plateau is made up of basalt rocks. Sometimes the molten magma cools down deep inside the earth’s crust. Solid rocks so formed are called intrusive igneous rocks.
(v) What do you mean by a rock cycle?
The process of transformation of rocks from one type to another due to changes in certain conditions in a cyclic manner is called a rock cycle.
(vi) What are the uses of rocks?
Rocks are useful for various purposes as mentioned below:
- For making roads
- Construction of houses and buildings
- Used in fertilisers
(vii) What are metamorphic rocks?
The type of rocks formed when igneous and sedimentary rocks experience heat and pressure are called metamorphic rocks.
2. Tick the correct answer.
(i) The rock, which is made up of molten magma, is
(a) Igneous
(b) Sedimentary
(c) Metamorphic
Ans: a
(ii) The innermost layer of the earth is
(a) Crust
(b) Core
(c) Mantle
Ans: b
(iii) Gold, petroleum and coal are examples of
(a) Rocks
(b) Minerals
(c) Fossils
Ans: b
(iv) Rocks which contain fossils are
(a) Sedimentary rocks
(b) Metamorphic rocks
(c) Igneous rocks
Ans: a
(v) The thinnest layer of the earth is
(a) Crust
(b) Mantle
(c) Core
Ans: a
3. Match the following.
| (i) Core | (a) Earth’s surface |
| (ii) Minerals | (b) Used for roads and buildings |
| (iii) Rocks | (c) Made of silicon and alumina |
| (iv) Clay | (d) Has a definite chemical composition |
| (v) Sial | (e) Innermost layer |
| (f) Changes to slate | |
| (g) Process of transformation of the rock Rocks |
Ans:
| (i) Core | (e) Innermost layer |
| (ii) Minerals | (d) Has a definite chemical composition |
| (iii) Rocks | (b) Used for roads and buildings |
| (iv) Clay | (f) Changes to slate |
| (v) Sial | (c) Made of silicon and alumina |
4. Give reasons.
(i) We cannot go to the centre of the earth.
Ans. We cannot go to the centre of the earth because the temperature and pressure at the centre of the earth are very high, and not just human beings but even rocks melt at the centre of the Earth.
(ii) Sedimentary rocks are formed from sediments.
Ans. The small fragments of rock that hit each other and break to reach the ground are called sediments. These sediments are transported and deposited by wind, water, etc., and then compressed and hardened to form a layer of rocks called sedimentary rocks. This shows that sedimentary rocks are formed from sediments.
(iii) Limestone is changed into marble.
Ans. Igneous and sedimentary rocks change into metamorphic rocks under heat and pressure. This happens in the case of limestone. Limestone, under heat and pressure, changes into marble, which is a metamorphic rock.
Explore Notes of All subjects of CBSE Class 7:-
| CBSE NCERT Notes Class 7 English | CBSE NCERT Notes Class 7 History | CBSE NCERT Notes Class 7 Geography |
| CBSE NCERT Notes Class 7 Civics | CBSE NCERT Notes Class 7 Mathematics | CBSE NCERT Notes Class 7 Science |
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FAQs
The earth’s crust is made up of various types of rocks. Any natural mass of mineral matter that makes up the earth’s crust is called a rock.
When the molten magma cools, it becomes solid. Rocks thus formed are called primary rocks.
When this molten lava comes onto the earth’s surface, it rapidly cools down and becomes solid. Rocks formed in such a way on the crust are called extrusive igneous rocks.
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