Important Questions for CBSE Class 7 Science Our Environment Chapter 2 - Inside Our Earth

Very Short Answer Questions: (1 Marks)

1. Fill in the blanks:

(i) The earth is a ___________planet.

Ans: The earth is a dynamic planet.

(ii) Earth is made up of several ___________layers.

Ans: Earth is made up of several concentric layers.

(iii) __________is the uppermost layer of the earth.
Ans: Crust is the uppermost layer of the earth.

(iv) The Oceanic crust is called as __________.

Ans: The Oceanic Crust is called Sima.

2. State true and false:

(i) Igneous rocks are made when the molten lava reaches the earth’s crust and solidifies.

Ans: True

(ii) The core is the innermost layer of the earth.

Ans: True

(iii) Gold, Petroleum, and Coal are examples of minerals.

Ans: True

(iv) The Crust is the thickest layer of the earth.

Ans: False

3. Match the following:

Ans:

3. Choose the correct option:

(i) Sial stands for__________.

(a) Silicon and Aluminium minerals

(b) Salon International

(c) Both a and b

(d) None of the above

Ans:(a) Silicon and Aluminium minerals

(ii) The center of the earth is__________.

(a) Core

(b) Mantle

(c) Stratosphere

(d) None of the above

Ans: (a) Core

5. Define the following:

(i) Rock

Ans: The mass of the mineral matter which is responsible for making the earth crust is known as rock.

(ii) Metamorphic Rocks

Ans: When igneous and sedimentary rocks are exposed to pressure and heat, they get transformed into a new type of rock known as metamorphic rock.

Short Answer Questions: (2 Marks)

6. Name the three layers of earth.

Ans: Crust, Mantle, and Core are the three layers of the earth.

7. What do you mean by the rock?

Ans: The mass of the mineral matter which is responsible for making the earth’s crust is known as rock.

8. What do you mean by metamorphic rocks?

Ans: With the action of heat and pressure, igneous and sedimentary rocks get transformed into metamorphic rocks.

9. What are the uses of the rocks?

Ans: Rocks are used for multiple purposes like in jewelry making, construction of roads, etc.

10. What is a rock cycle?

Ans: When one rock gets transformed into another rock, it is known as the rock cycle.

Short Answer Questions: (3 Marks)

11. Going to the center of the earth is not possible, why?

Ans: Following are the reasons which make it impossible to reach the center of the earth:

• High temperature and pressure

• Lack of oxygen

• $6000$km below the ocean floor.

12. How sedimentary rocks are formed?

Ans: Loose sediments get turned into layered rocks because of the application of intense pressure, these are known as sedimentary rocks. Small fragments of rocks etc. are transported by the air, water, etc. are called sediments.

13. How are marbles formed?

Ans: When limestone is subjected to intense heat and pressure, it gets converted into marble. Limestone is a sedimentary rock that gets transformed into a metamorphic rock known as marble.

14. What are rocks? Explain metamorphic rocks.

Ans: The mass of the mineral matter which is responsible for making the earth’s crust is known as rock. With the action of heat and pressure, igneous and sedimentary rocks get transformed into metamorphic rocks.

15. What are Mineral and Sial?

Ans: Minerals are naturally occurring substances and possess definite chemical composition. Sial stands for silicon and aluminum minerals. They comprise the formation of the earth’s crust. Si is the initials of silicon and likewise, al is the initials of aluminum.

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Long Answer Questions: (5 Marks)

16. Activity: Find the minerals used to make the daily pots of your home. Identify some other objects which are made from other minerals.

Ans: Minerals have specific physical properties, chemical composition, as well as they are naturally occurring substances. In doing this activity, students are supposed to collect items like ornaments, hammers, pans, nails, etc. including kitchen items too. Now they should make a list of minerals that are used in their formation. For example— iron and aluminum are used to make utensils, gold is used in the making of ornaments.

17. Explain rocks and their usefulness.

Ans: The mass of the mineral matter which is responsible for making the earth’s crust is known as rock. With the action of heat and pressure, igneous and sedimentary rocks get transformed into metamorphic rocks. 

Rocks are used for multiple purposes like in jewelry making, construction of roads, buildings, bridges, etc.

18. Explain the interior of the earth.

Ans: Interior of the earth has a different number of layers that are quite indifferent to each other. Moreover, the presented facts are based on volcanic eruptions and excavations as no one can go inside the earth due to high temperature and pressure. Scientists got to know about the interior of the earth by studying the material of volcanoes. 

Following are the different layers of the earth:

• Crust

• Lithosphere

• Mantle

• Core mantle boundary

• Outer Core

• Inner Core

19. Define different types of rocks.

Ans: There are three types of rocks:

• Igneous Rocks: The rocks that are formed after the cooling of the magma are known as igneous rocks. They are also known as the primary rocks.

• Sedimentary Rocks: Loose sediments get turned into layered rocks because of the application of intense pressure, these are known as sedimentary rocks. Small fragments of rocks etc. are transported by the air, water, etc. are called sediments.

• Metamorphic Rocks: The mass of the mineral matter which is responsible for making the earth’s crust is known as rock. With the action of heat and pressure, igneous and sedimentary rocks get transformed into metamorphic rocks. 

20. What are the different types of primary rocks?

Ans: Primary rocks are of two types:

• Extrusive Igneous Rocks: Rocks that are formed from the cooling of molten lava on the surface of the earth are known as extrusive igneous rocks. The cooled lava gets deposited on the earth’s crust and results in the formation of rocks.

• Intrusive Igneous Rocks: When the lava cools down inside the earth’s surface, it results in the formation of intrusive igneous rocks. For example, Granite.