Assam SCERT Class 7 Social Science Chapter 2 Interior of the Earth Question Answer Solution
Assam Board Class 7 Social Science Chapter 2 Interior of the Earth all Question’s easy Solution by expert teachers. Assam SCERT Class 7 Social Science (SST) Chapter 2 Interior of the Earth Solution.
Board |
Assam SCERT |
Class |
7 |
Book |
Social Science (SST) |
Topic |
Question answer |
Exercises:
1.) Choose the correct answer:
(a) The earth from its surface to the centre is composed of 4/3/2 layers.
ANSWER: The earth from its surface to the centre is composed of 3 layers.
(b) The earth’s crust is about 20/30/25 km thick.
ANSWER: The earth’s crust is about 20 km thick.
(c) The centre of the earth means crust/mantle/core.
ANSWER: The centre of the earth means core.
(d) Fossils are generally found in Sedimentary/Igneous/Metamorphic rocks.
ANSWER: Fossils are generally found in Sedimentary rocks.
(e) The hardest mineral is gold/diamond/zinc.
ANSWER: The hardest mineral is diamond.
2) Fill in the blanks-
(a) ————— increases as we go deeper from the crust to the interior of the earth.
ANSWER: Temperature increases as we go deeper from the crust to the interior of the earth.
(b) The earth’s crust is also known as ————-
ANSWER: The earth’s crust is also known as sial.
(c) Soil is composed of ———— and ———– matters.
ANSWER: Soil is composed of organic and inorganic matters.
(d) Rocks formed due to cooling of magma are called ———–
ANSWER: Rocks formed due to cooling of magma are called Intrusive igneous rocks.
(e) Minerals are generally ————– materials.
ANSWER: Minerals are generally inorganic materials.
3.) Write short notes (in about 30 words)
(a) What do you understand by earth’s crust?
ANSWER: From this chapter we understand that earth’s crust is about 20 km thick. In earth’s crust different mountains, plateaus, plains, seas, oceans are there. Earth’s crust is made up of different rocks like granite, basalt. Earth’s crust is also called “Sial” which is combination of silicon and aluminium.
(c) What is soil?
ANSWER:
Soil is an outer layer of earth’s crust. On soil we build different houses, transport systems. Soil is formed by rocks, when different factors apply on rocks to break rocks such as wind, heat, rain and other natural resources.
(e) What is ‘humus’?
ANSWER:
Humus present on soil. Humus is organic material present in soil. The dead animals and plants form humus in soil. Due to humus nutrients is supply to plants.
(b) What are igneous rocks?
ANSWER:
The hot liquid materials called “magma” which is present in interior of earth, cools down and form rocks which is called as “Igneous Rocks”. There are 2 types of Igneous Rocks. Intrusive Igneous Rocks and Extrusive Igneous Rocks.
(d) What are minerals?
ANSWER:
Minerals are the inorganic material which is form in earth’s crust by different natural processes. These are solid substances.
4.) Write answer (within 100 words)
(a) What are the different layers of the earth from its surface to the centre? Explain with diagrams.
ANSWER:
There are 3 different layers of the earth from its surface to the centre namely crust, mantle and core.
1) Crust: It is outer layer of earth also called as “sial”. This layer is average 20 km thick.
2) Mantle: It is 2nd layer of the earth from its surface. This layer is 2900 km thick. The density of this layer is more than earth’ Crust layer.
3) Core: It is innermost layer of earth. This layer is 3486 km thick. This layer is also called “Nife” combination of nickel and ferrous.
(b) Write about the types of rocks with examples.
ANSWER:
There are 3 different types of rocks namely
i) Igneous rock: The rocks of Khasi, Jaintia and Nilachal Hills are examples of igneous rock.
ii) Sedimentary rock: The rocks of Himalayas are examples of Sedimentary rock.
iii) Metamorphic rock: Marble slate, schist, Quartzite are examples of metamorphic rock.
(c) Find out the differences between rock and soil.
ANSWER:
Rock |
Soil |
1. The earth’s crust is made up of different types of rocks. |
1. The soil is one of the element which found on earth’s crust. |
2. Different minerals and metals are found in rocks. |
2. Soil is made up of rocks, different organic and inorganic materials. organic materials is also called as “Humus” |
(d) “No plants and animals can survive without soil”- Explain.
ANSWER:
In soil Humus is present which is organic material made from dead animals and plants. This humus supply various nutrients to plants from soil. It also increases water retaining capacity of soil. The water play important role in growth of plants. Hence for this reason no plants and animals can survive without soil.
5.) Names of different types of rocks are given in the box. Classify and write them according to their type in the table below.
Marble, Slate, Sandstone, Granite, Coal, Limestone, Chalk, Gneiss, Conglomerate, Mudstone, Schist, Quartzite, Basalt and Gabbro.
Igneous rock
Sedimentary rock
Metamorphic rock
ANSWER:
We have to classify given different types of rocks as igneous rock, Sedimentary rock and metamorphic rock.
Igneous rock– Granite, Basalt and Gabbro.
Sedimentary rock – Sandstone, Coal, Limestone, Conglomerate, Mudstone, Chalk
Metamorphic rock – Marble, Slate, Gneiss, Schist, Quartzite,
Assam SCERT Interior of the Earth