Natural Resources Class 9 Notes CBSE Science Chapter 14
CBSE NCERT based Class 9th Revision Notes Science contains Chapter 14 Natural Resources topics given in textbook are part of Revision Notes for Class
The Science Notes provide a comprehensive summary of the key concepts and topics presented in the NCERT TextBooks Class 9th Science. This chapter notes comprise detailed explanations of each topic and concept covered in the book, including natural resources such as oil, coal, natural gas, metals, stone, and sand. Additionally, the notes highlight the significance of water, air, and soil as three essential natural resources.
Well prepared Class 9th Science all Chapters Notes will guidance students understand the topics ,concepts and themes covered in all the chapters of Ncert Text book of 9th
Natural Resources Chapter 14 Science Notes
Biosphere
Biosphere means regions of Earth’s crust and atmosphere occupied by the living organism.
• Lithosphere is the outer solid crust of Earth which we call land. Its upper weathered part
forms the soil.
• Hydrosphere is the water component of Earth. 75% of the Earth’s surface covered with
water in the form of seas, rivers, lakes, ponds, dams, etc. Underground water is another
component of the hydrosphere.
• Atmosphere is the blanket of air that covers the whole Earth.
Types of Natural Resources
Biosphere
Lithosphere Hydrosphere Atmosphere
Natural Resources
Inexhaustible Exhaustible
Renewable Non - Renewal
Inexhaustible Natural Resources
They are natural resources, which occur in such abundance that they are not likely to get
exhausted despite continuous use, e.g., air, water, solar energy.
Exhaustible Natural Resources
They are natural resources which are available in limited quantity. They may to get depleted by
continuous and indiscriminate human consumption.
Exhaustible resources are of two kinds,
renewable and non-renewable.
Differences between renewable and non-renewable resources
Renewable Resources
Non-Renewable resources
1. These resources are replenished within
reasonable time.
1.Replenishment is not possible.
2. These resources can be used forever
provided they are used in limited
amounts.
2.These resources will ultimately lessen
and get exhausted.
3. They are both abiotic and biotic.
3.they are abiotic.
4. Their availability can be increased only
by enhancing replenishment.
4.Their increased exploitation will result
in quick exhaustion.
Examples. Forest, wildlife, underground
water* and soil.
Examples. Fossil fuels, minerals.
Q.Why is an equitable distribution of resources essential in a society? List two forces which
are against such distribution.
(AI 2017)
Ans. Equitable distribution of natural resources is necessary so that all and not just a handful of
rich and powerful people use them. Two forces against equitable distribution of resources
are :
• Industrialisation
• Profit makers who want to make profit from these resources
Air
Atmosphere
• The multilayered gaseous envelope surrounding the planet Earth is called atmosphere.
• It is divided into five distinct layer or zones : Troposphere, Stratosphere, Mesosphere,
Thermosphere (ionosphere) and Exosphere.
Composition of Gases in Air
Component
Percentage of volume
1.
Nitrogen (N2)
78.09
2.
Oxygen (O2)
20.93
3.
Argon (A) & Carbon dioxide (CO2)
0.98
Importance of Atmosphere
Role of Atmosphere in Climate Control
• The atmosphere covers the Earth, like a blanket.
• The atmosphere keeps the average temperature of the Earth fairly steady during the day.
• The atmosphere prevents the sudden increase in temperature.
• When UV radiations from sun strike the O2 molecules, it causes splitting of O2.
• Oxygen molecules react with energy atoms in the upper atmosphere to form Ozone (O3).
The Movement of Air : Wind
• Air movement in coastal area : In coastal area, during daytime, there is a regular flow of cool
air from the sea towards the land.
• At night, there is a reverse flow of air from land to sea. This happens because during the
daytime, land gets heated faster than water.
Air Pollution
• Air pollution is the addition of air pollutants such as particulate matter, gases and vapours
into the atmosphere, has an adverse effect on humans, animals, vegetation and human
assets.
• Natural (e.g., forest fire, dust storm, pollen).
• Human made (e.g., burning of fossil fuels in industries, mining, processing, stone crushing).
• Particulate air pollutants are also called suspended particulate matter or SPM because they
remain suspended in air for a good period of time.
Effects of Air Pollution of Human Beings
1. SPM casuses asthma, bronchitis and allergic cold.
2. Pollutant gases cause irritation in eyes, throat and lungs. They injure lings, liver, kidneys,
spleen and nervous system. Heart related diseases tend to increase. Many people develop
terminal ailments such as cancer.
3. Hydrocarbon vapours not only damage the internal organs, but also cause cancer.
4. SO2 reacts with water in the atmosphere to form sulphuric acid. This sulphuric acid is
washed down into the soil by rain (acid rainfall) where it may make the soil highly acidic,
thus, affecting the growth of plants and ultimately the forest growth.
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