Inside Our Earth Class 7 Worksheet Geography Chapter 2

Q.1. What is the radius of earth?

The radius of the earth is 6371 km.

Q.2. What are the three layers of the earth?

The three layers of the earth are crust, mantle and core.

Q.3. What are the main mineral constituents of the continental mass?

The main mineral constituents of the continental mass are silica and alumina.

Q.4. What are metamorphic rocks?

When the igneous and sedimentary rocks are subjected to heat and pressure they change into metamorphic rocks.

Q.5. Write about the deepest mine in the world.

The deepest mine in the world, is in South Africa. It is about 4 km. deep. In search for oil engineers have dug a hole about 6 km. deep.

Q.6. What happens to igneous and sedimentary rocks when they are subjected to great heat and pressure?

Igneous and sedimentary rocks change into metamorphic rocks under great heat and pressure.

Q.7. What are the uses of rocks?

Uses of rocks

• The hard rocks are used for making roads, houses and buildings.
• Stones are used in many games. For example, seven stones (pitthoo), hopscotch (stapu/kit kit), five stones (gitti).

Q.8. Sedimentary rocks are formed from sediments. Give reason.

Rocks roll down, crack, and hit each other and are broken down into small fragments. These smaller particles are called sediments. These sediments are transported and deposited by wind, water, etc. These loose sediments are compressed and hardened to form layers of rocks. These types of rocks are called sedimentary rocks.

Q.9. Write a note on various types of rocks?

There are three major types of rocks: igneous rocks, sedimentary rocks and metamorphic rocks.

1. Igneous rocks - When the molten magma cools, it becomes solid. Rocks thus formed are called igneous rocks. They are also called primary rocks. There are two types of igneous rocks: intrusive rocks and extrusive rocks.

• Extrusive igneous rocks - When molten lava comes on 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. For example, basalt.
• Intrusive igneous rocks - Sometimes the molten magma cools down deep inside the earth’s crust. Solid rocks so formed are called intrusive igneous rocks. Granite is an example of such a rock.

2. Sedimentary rocks - Rocks roll down, crack, and hit each other and are broken down into small fragments. These smaller particles are called sediments. These sediments are transported and deposited by wind, water, etc. These loose sediments are compressed and hardened to form layers of rocks. These types of rocks are called sedimentary rocks. For example, sandstone is made from grains of sand.

3. Metamorphic rocks - Igneous and sedimentary rocks can change into metamorphic rocks under great heat and pressure. For example, clay changes into slate and limestone into marble.

Q.10. What are igneous rocks?

When the molten magma cools, it becomes solid. Rocks thus formed are called igneous rocks.

Q.11. Limestone is changed into marble. Give reason?

Marble is a metamorphic rock that forms when limestone is subjected to great heat and pressure.

Q.12. What do you mean by a rock cycle?

One type of rock changes to another type under certain conditions in a cyclic manner. This process of transformation of the rock from one to another is known as the rock cycle.

Q.13. What is the core of the earth made up of?

It is mainly made up of nickel and iron.

Q.14. Name the monument which is made of red sandstone?

The Red Fort is made of red sandstone.

Q.15. What is the Latin word for igneous?

Latin word for igneous is Ignis meaning fire.