You must have heard about the water scarcity in Bangalore, Chennai, Rajasthan, and Qatar. You must have thought of many solutions also regarding the problem. But you can’t arrive at a correct and practical solution without a proper understanding of all the natural resources.
So, this chapter will give you a better understanding of all-natural resources. In this chapter, you will learn about the role of the atmosphere in climate control, different natural resources, carbon cycle, nitrogen cycle, etc.
NCERT Solution Class 9 Science of Chapter 14 includes all Intext exercises and an NCERT exercise for you. The NCERT exercise includes solutions to all 6 questions given in your NCERT Textbook. You can practice these questions to test and enhance your analysis skills & cognizance
NCERT Solution for Class 9 Science Chapter 14: Natural Resources Ex 14.1
How is atmosphere different from the atmosphere on Venus and Mars?
The atmosphere of Earth contains a mixture of many gases like nitrogen (78%), oxygen (20.950 0). carbon dioxide (0.031%) and water vapour (in varying proportion), whereas, the atmosphere on Venus and Mars mainly contains carbon dioxide, that makes about 95-97% of atmosphere. This may also be the reason for no life on Venus and Mars.
How does the atmosphere act as a blanket?
The atmosphere mainly consists of air and covers the Earth like a protective blanket. The air is a bad conductor of heat. So, it keeps the average temperature of Earth fairly steady during the day and even during the course of whole year.
In addition, the ozone shield of the atmosphere protects life from harm] ultraviolet radiations of the sun.
What causes winds?
The uneven heating of the atmosphere in different regions of the Earth causes winds. The rotation of Earth and the presence of mountain ranges, also help in the formation of wind.
How are clouds formed?
Water bodies are heated by solar radiations during the day and large amount of water vapour goes into the air. Air also gets heated due to sunlight and starts rising up along with water vapours. As the air rises, it expands and cools. This cooling causes water vapours in the air to condense in the form of tiny droplets. Condensation of water is facilitated by dust and other suspended particles which act as nuclei. The collection of these tiny droplets of water appears in the form of clouds.
List any three human activities that you think would lead to air pollution.
The following human activities would lead to air pollution
(i) Excessive burning of fossil fuels, i.e. coal and petroleum. It produces large amount of oxides of Nitrogen and Sulphur (i.e. NOPSOZ). These oxides mix with air and cause acid rain leading to many harmful effects.
(ii) Many industries release high amount of poisonous gases like carbon monoxide (CO) into the atmosphere causing air pollution.
(iii) Forest fires, excessive use of chlorofluorocarbons (CFCs) refrigerators, excessive mining and ore refining release harmful gases into the air leading to its pollution.
‘Why do organisms need water?
Organisms need water because
(i) It provides a medium for all the cellular processes to take place.
(ii) It is necessary for the transpiration of substances from one part of the body to the other in dissolved form.
(iii) It helps to maintain body temperature.
(iv) It is required to maintain balance of salts within the body.
What is the major source of freshwater in the city/town/village where you live?
In city/town/village, the major source of water is underground water. It is drawn with the help of hand pumps and tube wells. The other nearby sources are rivers, lakes and ponds.
Do you know of any activity which may be polluting the water source?
The activities, which may be polluting the water bodies, are
(i) Sewage and 0the wastes being dumped into water bodies, which deplete water quality.
(ii) Industries use water for cooling in various machines and later release this hot water into water bodies. This causes sudden change in temperature of water that affects the aquatic organisms.
How is soil formed?
The formation of soil occurs by the process of weathering. Weathering is the breakdown of hu ge rocks into smaller mineral particles.
It can occur by following three means
(i) Physical Weathering- This is the pulverisation of rocks by mechanical forces, exerted by either flowing water, winds or humidity or by wetting drying, freezing of water leading to cracks in rocks.
(ii) Chemical Weathering – It involves chemical , action such as oxidation, reduction, carbonation and solublisation of rocks causing their weathering.
(iii) Biological Weathering Living organisms also cause weathering, e.g. big trees expand their roots in rocks creating crevices which further widen up the growing of roots.
What is soil erosion?
The removal and transpiration of the top layer of soil from its original position due to factors such as strong winds or fast running water is called soil erosion. It normally occurs in barren areas (areas without plant) and get accelerated in hilly or mountains regions. Soil erosion results in desertification and reduction in soil fertility.
What are the methods of preventing or reducing soil erosion?
Preventive methods of soil erosion are as follows:
2) Contour Ploughing
3) Step (terrace) Farming
4) Soil Cover
5) Over grazing
What are the different states in which water is found during the water cycle?
During the water cycle, water is found in solid state (snow, ice. etc.), liquid state (ground water, river water, etc.) and gaseous state (water vapours).
Name two biologically important compounds that contain both oxygen and
The biologically important compounds that contain both oxygen and nitrogen are nitrates (N02) and nitrates (N03).
List any three human activities which would lead to an increase in the carbon dioxide content of air.
The human activities which would lead to an increase in CO2 content of air are;
Deforestation increases the level of C02 in the environment.
Respiration is the natural way to release of C02 by plants. It is balanced by the release of oxygen by plants. 50, it is not harmful for the environment.
Combustion of Fuels leads to increase in C02 level in the atmosphere. Fuels are burnt to carryout activities like cooking, transportation and in industrial processes.
What is the greenhouse effect?
Some gases like carbon dioxide, methane, nitrous oxide prevent the escape of heat from the Earth’s surface by trapping it. This increases the average temperature of the Earth. This is called the green house effect. An increase in the content of such gases would lead to a situation of global warming.
What are the two forms of oxygen found in the atmosphere?
The two forms of oxygen found in the atmosphere are; Elemental oxygen is normally found in the form of diatomic molecule (02) in the lower part of atmosphere. It is about 21% in the air and nonpoisonous. Ozone is found in the stratosphere part of atmosphere. It contains three atoms of oxygen (O3).
Why is the atmosphere essential for life?
Atmosphere is essential for life due to following reasons: It maintains the appropriate climate for the sustain of life.
It keeps the average temperature of the Earth steady during the day and even throughout the year. It prevents the sudden increases in temperature during the daylight hours. The gases it contains are required for sustaining life on Earth. These gases are:
Oxygen, Carbon dioxide and Nitrogen
A thick layer of ozone (in stratosphere) of atmosphere hlters the harmful UV radiations reaching the Earth. The UV rays produce harmful effects on all living organisms.
Why is water essential for life?
Water is essential for life because of these reasons: It provides medium to carry out all the cellular processes.
All the reactions that occur in our body and within cells occur between substances that are dissolved in water. It is required for the transportation of materials from one part of the body to the other.
It helps to maintain body temperature. Water makes up about 70% of body weight of all the living organisms.
How are living organisms dependent on soil? Are organisms that live in water totally independent of soil as a resource?
Living organisms depend on soil in the following ways:
Soil helps to bind the roots of plants to provide them anchorage. The nutrients in soil are absorbed by the plants for their growth and development.
It provides natural habitat for various living organisms, e.g., bacteria, fungi, algae, earthworms, etc. These help to maintain the fertility of soil. Many animals like rats, rabbits, etc., make their home in the soil. Earthworm performs all its activities in the soil. It maintains the fertility of soil by releasing nitrogen rich excreta.
Organisms that live in water are not totally independent of soil as a resource. These organisms depend on aquatic plants for food and other substances These aquatic plants in turn require minerals for their sustenance These minerals are carried to water bodies from SOII by rivers, rain water, etc. without the supply of minerals from the soil to the water bodies, it is impossible to imagine aquatic life.
You have seen weather reports on television and in newspapers. How, do you think we are able to predict the weather?
Meteorologists collect information regarding the pattern of temperature, speed of wind, air presser and all other features which influence weather. All these information are collected by remote sensing and weather forecast satellites. This information is then compiled in meteorological departments which prepare a weather report that is displayed on the maps. This information is
further transmitted through radio, television and newspaper.
We know that many human activities lead to increasing levels of pollution of the air, water-bodies and soil. Do you think that isolating these activities to specific and limited areas would help in reducing pollution?
Yes. Isolating human activities to specific areas would help in reducing levels of pollution. For example, setting up of industries in isolated regions will control pollution to some extent. The pollution caused by these industries will not contaminate water resources, agriculture land, fertile land, etc.
Write a note on how forests influence the quality of our air, soil and water
Forests influence the quality of air, soil and water resources in the ways as below:
A. Influence of forests on air : Forests help to maintain oxygen and carbon dioxide balance in the air, they reduce the level of C02 In the air and to prevent greenhouse effect. These maintain temperature of the environment; Forests increase the rate of photosynthesis in surrounding region.
B. Influence of forests in quality of soil: Trees spread their roots deep inside the Earth and bind the SOII particles firmly. This reduces soil erosion. Forests help to maintain nutrient cycles (biogeochemical cycles) in the atmosphere.
C. Influence of forests in quality of water: Water cycle will be maintained by the help of trees Forests conserve water and make them available on the surface of Earth as water sources.