Important Questions Class 7 Social Science Our Environment Chapter 2
Important Questions Class 7 Social Science Our Environment Chapter 2
Geography is a field which studies the planet’s ecosystems, regions, populations, and landscapes. Since it is logical to assume that humans have always been curious about the rest of the world, many people think that geography is the oldest of all disciplines. The second chapter of Class 7 Social Science, Our Environment is Inside Our Earth. Our planet, Earth, is dynamic. Both the interior and the outer parts are always changing. The crust, mantle, and core make up the interior of the Earth. Rocks of many sorts make up the crust of the world. Rocks are divided into three categories: igneous rocks, sedimentary rocks, and metamorphic rocks. Chapter 2 Class 7 Social Science Our Environment Important Questions help connect with the concepts of Inside the Earth. Students can easily access all this and more on the Extramarks website.
At Extramarks, we acknowledge the role of answering the important questions for each chapter in a subject such as Geography. The NCERT textbook, other reference books, past exam papers, and other sources have all been used by Extramarks professionals to compile Social Science Our Environment Class 7 Chapter 2 Important Questions. Our Geography specialists have created a list of step-by-step answers to help students comprehend each chapter. Students may readily get these solutions by registering with Extramarks right away.
Not just limited to Class 7 Social Science Our Environment Chapter 2 Important Questions, students can easily access materials like NCERT Solutions, CBSE revision notes, past years’ question papers, NCERT books, and more on the Extramarks website.
Important Questions Class 7 Social Science Our Environment Chapter 2- with Solutions
Social Science experts of Extramarks have developed an entire list of Important Questions Class 7 Social Science Our Environment Chapter 2 with the help of different resources. The Earth is a dynamic planet. Both the inside and the outside are always evolving. The interior of the Earth is made up of the crust, mantle, and core. The world’s crust is made up of a variety of rocks. Igneous rocks, sedimentary rocks, and metamorphic rocks are the three types of rocks that are found on Earth. Minerals are naturally occurring substances with certain physical traits and well-known chemical compositions. These questions and solutions help students better comprehend the chapter Inside Our Earth.
Mentioned below are a few Important Questions Class 7 Social Science Our Environment Chapter 2:
Question 1. What are metamorphic rocks?
Answer 1. The rocks that are created under intense pressure and heat are known as metamorphic rocks.
When exposed to heat and pressure, igneous and sedimentary rocks change into metamorphic rocks. For instance, limestone transforms into marble and clay into slate.
Question 2. Describe the Earth’s interior.
Answer 2. There are several layers in the Earth’s interior, all of which are interrelated to one another. What we know today about the Earth’s interior is completely based on volcanic eruptions and excavations since it is dangerous to penetrate inside the ground owing to the intense pressure and temperature. Scientists learned more about the planet’s innards by examining volcanic debris.
The various layers of earth are listed below:
- Crust
- Lithosphere
- Mantle
- Core mantle boundary
- Outer core
- Inner core
Question 3. What are the three layers of the Earth?
Answer 3. The core, mantle, and crust are the three layers of the Earth.
Question 4. Mineral and Sial: what are they?
Answer 4. Minerals are substances that are created naturally and have a certain chemical makeup. Sial stands for the minerals silicon and aluminium. They are a part of how the crust of the planet is formed. Al and Si are the initials for aluminium and silicon, respectively.
Question 5. What are the uses of rocks?
Answer 5. The uses of rock include the following:
- For building homes, buildings, and other constructions
- For drilling and cutting purposes
- The preserved remains of plants and animals found in rocks are helpful to science.
- Diverse rocks contain minerals used to make fuel, medications, fertilisers, and other products.
Question 6. What causes the formation of marble?
Answer 6. Limestone transforms into marble when it is exposed to high heat and pressure. Marble is a metamorphic rock developed from limestone, a sedimentary rock.
Question 7. What is a rock?
Answer 7. A rock is any naturally occurring mass of mineral materials in the planet’s crust. Rocks of diverse forms, sizes, colours, and textures make up the world’s crust.
Question 8. How are sedimentary rocks formed?
Answer 8. Sedimentary rocks are created when loose sediments are subjected to extreme pressure and transform into layered rocks. Sediments are the little pieces of rocks, etc., that are carried by air, water, etc.
Question 9. What does a rock cycle mean?
Answer 9. The change of one type of rock into another under specific cyclical conditions is known as the rock cycle. For instance, igneous rocks, which form when molten lava hardens, can disintegrate into tiny particles that can then be transported and deposited to form sedimentary rocks. When heat and pressure are applied, sedimentary and igneous rocks change into metamorphic rocks. These metamorphic rocks may disintegrate to produce sedimentary rocks or melt in the presence of intense heat and pressure to produce molten magma, which would then solidify to produce igneous rocks.
Question 10. Name three types of rocks.
Answer 10. The three types of rocks are known as:
- Metamorphic rocks
- Igneous rocks
- Sedimentary rocks
Question 11. How are extrusive and intrusive rocks formed?
Answer 11. Both extrusive and intrusive forms of rocks are igneous. When molten lava from the Earth’s interior comes to the surface, cools, and solidifies on the crust, extrusive rocks are produced. These rocks have exceptionally fine-grained structures. Take basalt as an illustration. When molten lava cools and hardens deep below the Earth’s crust, intrusive rocks are created. Due to their gradual cooling, they produce large grains. An excellent example of this rock is granite.
Question 12. What is lava?
Answer 12. Lava is known as the heated, crimson magma that rises to the surface from the Earth’s core. It solidifies as it cools.
Question 13. Which two categories of rocks are igneous?
Answer 13. Lava cools as it solidifies into igneous rocks. Extrusive igneous rock like basalt is created when the lava cools on the crust. They are finely textured.
Intrusive igneous rocks occasionally occur when the material cools down rapidly deep inside the crust. For instance, granite has big granules. Granite is used for making grinding stones.
Question 14. Give reasons for the following statement.
- We cannot go to the centre of the Earth.
- Sedimentary rocks are formed from sediments.
- Limestone changes into marble.
Answer 14. The following are the reasons for the points mentioned above:
- We cannot go to the Earth’s centre: The Earth’s core, around 6000 kilometres below the ocean’s surface, is characterised by extremely high pressure and temperature. There is just molten magma at the centre of the Earth. Oxygen is absent. Any living thing/creature would not be able to endure such circumstances. We are unable to reach the Earth’s core as a result.
- Sedimentary rocks are formed from sediments: Sediments are the little pieces of rock that collide and shatter as they travel to the ground. These sediments are carried and deposited using wind, water, etc., and after being crushed and solidified, they create a layer of sedimentary rocks. This demonstrates how sediments give rise to sedimentary rocks.
- Limestone changes into marble: Under heat and pressure, igneous and sedimentary rocks transform into metamorphic rocks. This occurs in the case of limestone. Marble, a metamorphic rock, is created when pressure and heat are applied to limestone.
In the above section of Important Questions Class 7 Social Science Our Environment Chapter 2, all the essential topics of the chapter are covered.
Benefits of Solving Important Questions Class 7 Social Science Our Environment Chapter 2
As was already established, geography has long and storied roots spanning the world. The Important Questions section of Extramarks is recommended reading for students. This collection of important questions helps the students grasp this subject. Students gather confidence by answering the important questions and going over their solutions.
Mentioning below are some benefits of solving Important Questions Class 7 Social Science Our Environment Chapter 2:
- Important Questions Class 7 Social Science Our Environment Chapter 2 covers the concepts of the entire chapter- Inside Our Earth.
- Students can entirely rely upon these important questions as they are made following all the guidelines laid by CBSE.
- Geography comprises challenging chapters—all the intricacies of the chapters are in these important questions by Extramarks.
Q.1 What is the difference between lava and magma?
Ans
(1) Hot molten rock is called magma when it is inside the Earth, and when the hot molten rock reaches the surface of the Earth, it mixes with steam and gas and turns into lava.
(2) When magma cools inside the Earth, it has large minerals, because it cools slowly. Lava has very small minerals because it cools quickly.
(3) Lava is slightly cooler than magma, glows a different color, and it is made up of different substances (because of the steam and gas added to it). When gas and steam was mixed in with magma it changed some chemicals.
Q.2 What rocks have been used to make the following buildings?
(a) Red fort
(b) Taj Mahal
Ans
a) Red sand stone
b) White Marble
Q.3 What is the radius of the earth?
Ans
The radius of the earth is 6,378 km.
Q.4 What are fossils?
Ans
The remains of the dead plants and animals trapped in the layers of rocks are called fossils.
Q.5 Write any four fields where minerals are used.
Ans
Minerals are used in:
(1) In industries, e.g., iron
(2) In jewellery, e.g., gold
(3) In medicines, e.g., sodium
(4) In fertilizers, e.g., potassium.
Q.6 What are minerals?
Ans
Minerals are naturally occurring substances, which have certain physical properties and definite chemical composition, e.g., Cadmium, diamond, lead, etc.
Q.7 Define Rock cycle.
Ans
When one type of rock changes into another type, under certain conditions in a cyclic manner. This process of transformation of the rock from one to another is known as rock cycle. When the molten magma cools; it solidifies to become igneous rock. These igneous rocks are broken down into small particles, that are transported and deposited to form sedimentary rocks. When the igneous and sedimentary rocks are subjected to heat and pressure they change into metamorphic rocks. The metamorphic rocks which are still under great heat and pressure melt down to form moltan magma. This moltan magma again can cool down and solidify into igneous rocks.
Q.8 How are rocks useful to us?
Ans
Rocks are very useful to us. The hard rocks are used for making roads, houses and buildings. Stones are used for making jewellery. Rocks contain minerals which are very useful to us.
Q.9 How are metamorphic rocks formed? Give two example.
Ans
Igneous and sedimentary rocks can change into metamorphic rocks under great heat and pressure. The chemical composition of these rocks change and new rocks get formed. Example: Clay changes into slate and limestone into marble.
Q.10 How are sedimentary rocks formed? Give two example.
Ans
Sediments are transported and deposited by wind and water. These loose sediments are compressed and hardened to form layers of rocks. These rocks are called sedimentary rocks e.g. sandstone and limestone.
Q.11 Define sediments.
Ans
Rocks roll down, crack, and hit each other and are broken down into small fragments. These smaller particles are called sediments.
Q.12 How are intrusive igneous rocks formed?
Ans
Sometimes the molten magma cools down deep inside the earth’s crust. So solid rocks are formed these are called intrusive igneous rocks, e.g., granite.
Q.13 How are extrusive igneous rocks formed?
Ans
Lava is a molten magma that erupts from the interior of the earth on its surface. When this molten lava reaches 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. e.g. basalt.
Q.14 What are igneous rocks? Give two example.
Ans
When molten magma cools, it becomes solid rocks are called igneous rocks. Igneous rocks are of two types intrusive and extrusive. E.g. basalt and granite.
Q.15 What are primary rocks?
Ans
Igneous rocks are called primary rocks because from these rocks all other rocks are made. They are the first primary rocks to be formed from new lava, E.g., basalt, granite.
Q.16 What are the three different types of rocks?
Ans
Igneous, Sedimentary and metamorphic rocks are the three types of rocks.
Q.17 What is a rock?
Ans
Any natural mass of mineral matter that makes up the earth’s crust is called a rock. Rocks can be of different colours, sizes and textures.
Q.18 Describe the ‘core’.
Ans
The innermost layer is the core with a radius of about 3,500 km. It is mainly made up of nickel and iron and is called ‘nife’ (ni-nickel, fe-iron). The central core has very high temperature and pressure.
Q.19 Describe the ‘mantle’.
Ans
Just beneath the crust is the mantle, which extends up to a depth of 2900km below the crust. It is the middle layer of the earth.
Q.20 Describe the Lithosphere or the crust.
Ans
The uppermost layer over the earth’s surface is called the crust. It is the thinnest of all the layers. It is about 35 km on the continental masses and only 5 km on the ocean floor.
Q.21 What is “sima”?
Ans
The oceanic crust mainly consist of silica and magnesium. It is called sima (si-silica; ma – magnesium).
Q.22 What is “sial”?
Ans
The main mineral constituents of the continental mass are made of silica and alumina. It is thus called sial. (si from silica, al from alumina.)
Q.23 How was the Earth formed?
Ans
The earth was formed 5 billion years ago. It was extremely hot and in molten state, but it slowly cooled and acquired the present shape. The heavier elements like iron and nickel gathered in the interior of the earth and the lighter elements like silicon formed the exterior of the earth.
Q.24 Write a note on crust?
Ans
The earth is made of concentric layers.
1. The uppermost layer of the earth is known as crust.
2. It is very thin; the average thickness is about 35 km under the continents and 5 km under the oceans.
3. The crust under the continents is made of silica + aluminium and is called sial.
4. The crust under the oceans is made of silica + magnesium and is called sima.
Q.25 Define plates. How do they move?
Ans
The earth’s lithosphere is broken up into several pieces. These pieces are known as plates.
These plates float on asthenosphere. The flow of partially molten material within the asthenosphere causes the plates to move relative to each other. As the plates move, they push, pull, slide, rise, sink, bend and break.
Q.26 In the diagram given below, label the various layers of the earth.
Ans
Q.27 How did the rocks derive their names?
Ans
The earth is composed of three main rocks, i.e., the igneous, the sedimentary and the metamorphic. Each name has a meaning:
Igneous is derived from the Latin word ‘Ignis’ meaning fire.
Sedimentary is derived from the Latin word ‘Sedimentum’ meaning settle down.
Metamorphic is derived from the Greek word ‘Metamorphose’ meaning change of form.
Q.28 How is the upper mantle different from the lower mantle?
Ans
| Upper mantle | Lower mantle |
| 1. It is about 670 km thick. | 1. It is about 2,200 km thick. |
| 2. It has very high temperature. | 2. The temperature is moderate. |
| 3. It begins at the depth of 50 km and extends upto the depth of 300 km. | 3. It begins at the depth of 700km and extends upto the depth of 2900km. |
| 4. The top layer is solid and lower layer is soft layer. | 4. It is composed of uniform hard rocks. |
Q.29 What are the various criteria to differentiate various rocks?
Ans
The rocks can be differentiated on the basis of:
colour, texture and size.
On the basis of texture, there are two types of rocks: Fine grained like basalt and large grains like granite.
On the basis of colour, there two types of rocks: Light like granite and dark like gabbro.
On the basis of size, there are many types of rocks: boulders, pebbles, gravels and sand.
Q.30 Name some of the main minerals which form the layers of the earth.
Ans
The earth’s interior is made of three layers. These layers are made of various minerals in different proportion. Some of the common minerals are:
- iron
- silica
- nickel
- aluminium
- magnesium
- sulphur.
Q.31 Name some of the games which use stones.
Ans
Some of the games that use stones are:
1. Stapu or hopscotch
2. Pitthoo or seven stones
3. Gitti or five stones
4. Marbles
5. Knuckle bone game.
Q.32 Name some rocks used as building material.
Ans
Rocks like marble, granite, basalt and sand stone are good building materials.
Q.33 Why sedimentary rocks are also called stratified rocks?
Ans
Sedimentary rocks are formed due to deposition of sediments in layers. They harden over the years because of weight of layers one above the other. So, it has various layers of sediments; therefore, it is called stratified rocks.
Q.34 Define asthenosphere.
Ans
The asthenosphere is the layer of the earth that lies at a depth 60–150 miles (100–250 km) beneath the earth’s surface. The asthenosphere gets its name from the Greek word for weak, i.e., ‘asthenis’ because of the relatively fragile nature of the materials of which it is made up of. It lies within the upper mantle and the lithosphere floats on it.
Q.35 Why are coal and petroleum called fossil fuels?
Ans
Petroleum and coal are formed by the decay of the remains of dead plants and animals that were buried with sediments million of years ago. The high pressure and temperature under the earth surface converted these into carbon and hydrocarbons, i.e., the main constituents of coal and petroleum. The remains of plants and animals trapped within the rock layer are called fossils. Therefore, they are called fossil fuels.
Q.36 Why it is difficult to go deep inside the earth?
Ans
It is difficult to go to the centre of earth because to reach there we have to dig a hole of 6000m deep on ocean floor.
Q.37 Name some of the minerals found in sedimentary rocks.
Ans
Some of the minerals found in sedimentary rocks are: Halite, Gypsum, Quartz, Mica, clay minerals etc.
Q.38 Give two examples of metamorphic rocks.
Ans
The examples of metamorphic rocks are: clay changes into slate and limestone into marble.
Q.39 Where is the world’s deepest mine situated?
Ans
Mponeng Gold Mine is the world’s deepest mine, situated south-west of Johannesburg in South Africa. The operating depth of Mponeng mine ranges between 2.4km to more than 3.9km below the surface by the end of 2012 is a gold mine in South Africa. It is 3.9 kilometers deep (2012) and is in operation.
Q.40 In which rock will you find fossils?
Ans
Fossils are commonly found in sedimentary rocks.
Q.41 Which layer of the earth has highest temperature and pressure?
Ans
The central core has both high temperature and pressure.
Q.42 Name an edible mineral.
Ans
The rock salt used in our food everyday is a mineral.
Q.43 Why is inner core solid whereas the outer core is molten?
Ans
At the centre of the earth, the pressure due to the upper layers is very high. Under that pressure, the iron density increases drastically, also increasing the temperature that makes it turns to a liquid. So, the inner core can be considered to be substantially rigid, i.e., solid.
Q.44 What do you understand by nife?
Ans
Nife is made from two words ni + fe. Ni means nickel and fe means iron. They form the core.
FAQs (Frequently Asked Questions)
1. What does Chapter 2 of the class 7th textbook of Social Science say about the globe?
A globe is nothing more than a miniature version of our planet. The Earth is shaped more like an orange than the globe, which is spherical. The geoid is the name given to this form. Globes come in a variety of shapes. They may be generally classified into two types: celestial globes and terrestrial globes. The maps of the planet are on the terrestrial globe, while the celestial globe is used to chart the stars. To know more about it, students can refer to Extramarks Important Questions Class 7 Social Science Our Environment Chapter 2.
2. According to Chapter 2 of the class 7 textbook of Social Science Our Environment, what is meant by rocks and minerals?
Some rocks include crushed plant material or the shells of extinct animals. Minerals are naturally occurring inorganic compounds or elements with a well-ordered internal structure, chemical makeup, crystal structure, and physical features. All of these are similar to the building blocks of our planet. Thus, it is important to study their qualities to understand their origin, processes, etc. thoroughly. If students have further questions about this topic, they can refer to Extramarks Important Questions Class 7 Social Science Our Environment Chapter 2.
